Here you go Jason (and anyone else that cares to take a read)....
Thanks in advance for the sources of information - you know who you are!!!
Three cars that I know of have blown up whilst doing a sustained high speed pull in top gear. All three at around 6000 revs /160 mph.
Detonation from high combustion temperatures is the problem. Don\'t go beyond 14 psi on 98 octane. On really hot days you are still pushing it, even at this pressure.
You cannot \'tune\' this problem out by retarding the ignition. In fact, this raises combustion temps further!
My advice: Use either or both Water Injection (with methanol) and C16 or similar race fuel over 14 psi. Mixes fine with regular SUL.
Could explain more, but the thread would be a mile long!
Regards
Max
Max:
Care to elucidate us on how retarding timing increases the propensity for detonation to occur, as this is a new one on me. It will increase exhaust gas temperature sure, but unless you have heated the entire chamber to the point where self igntion will occur spark or not I\'m not seeing the mechanism.
Would also be interesting if anyone was logging coolant temperatures and AFRs when these bangs occured and if these were dyno deaths or track deaths.
But I do agree that WI is the way to go for serious HP. Just I\'d do it without the air/air intercooler getting in the way.
Bill
Max
2 questions
How much ignition at that point?
where is the wideband placed and what wideband?
At that point my car is at the moment is at 11-12 my egts are under 800.
Has the timing been checked to make sure that what is in the map is what they are getting?
Intake and water temps?
Sorry more than 2 questions
more this is the stuff I love:D
Also what spark plugs are they using?
Track/strip deaths - 2 of them at TOTB2 during the high speed runs...
Sounds like yer basic system problem, in that the system has not been designed to cope with that level of duty cycle.
towit: the heat is building up faster than it can be removed. Solvable anyway.
Wish I had the time or someone would pay be enough to play with this sort of gear full time...Sigh. Its horrid being an engineer but having to pay a big mortgage.
Sorry for the delay, caught me mid Prawn Cocktail Roll ;)
Most of this info has come via Australia, NZ and the US, and appears to solve the problems we are having now.
At the time mine went pop, my A/F ratio was 11:1.
Water temp was 95 degrees.
Timing was broadly similar to stock timing at that point, about 12-15 degrees leading?? off the top of my head - laptop is at home!
Lambda is in the midpipe. Motec Professional Lambda Meter.
Intake temps - who knows! At 160 mph I was looking at the runway, not my commander LOL!. Wasn\'t logging either, but did glance at my lambda meter (I do out of habit, along with water temp). It was a real hot day though.
No, have not checked timing, but allegedly the Apexi is fairly accurate in this department.
I was running 9 plugs leading and trailing, don\'t know about the other two. One of these cars was a single turbo as well.
Bill - I am not suggesting \'in general\' that reducing timing increase detonation risk, but that in this application in these conditions, with high boost and already high combustion temperatures, retarding the ignition will increase EGT.
Higher EGT means higher combustion temperature?, and internal components raising in temperature more also, no? I could be wrong though! Please correct me if this is the case.
I am not an expert by any means, just very inquisitive and like to research things like this. I don\'t fancy paying for another rebuild :(
Many engines IMO last as long as they do because the owners only give their engines short blasts of power. Drag racing is short and sweet. The sustained pulls are the problem, where the engine internals get sufficient time to get super duper hot.
Yep, yer right Bill :) your towit description is bang on. These engines are just not designed for the punishment we try to put then through.
Regards
Max
I know I am not a rx7 mechanic and don\'t have the technical know how of many but here\'s my take on this issue.
*Surely it\'s because the car has not been mapped properly*
Reason I say this is because a standrad rx7 will do 160mph anyway and many owners of rx7 have done this repeatedly with no problem. We\'re not dealing with a case of a car that has a top end of 145mph and it\'s been modified and blowing at 160mph, we\'re dealing with a car that does 160mph as stock. The standard twin turbo setup wth stock intercooler etc will surely produce far greater heat at 160mph than these modified cars that have blown at these speeds, so surely that would eliminate the heat issue?
Don\'t anyone take it personal or the wrong way just voicing my opinion on this topic.
:)
I\'ll try and pop out a full answer tonight...
It is impossible to offend me Brian :)
The one factor that differentiates a stock car doing 160 and a tuned car doing 160 is the pressure in the combustion chamber.
Running stock boost levels, does not appear to be problematic.
Regards
Max
(I\'m getting to like this thread!)
I dont understand why this is not a mapping problem, I have had both my cars over 160 more times than i can remember and not just for a short spurt as at totb.
Mine ran fine as well Gary, if it helps.
I had ran for months at one bar and done plenty of absolutely flat out runs.
I think the difference when mine went was that my car had sat in the heat with engine running and a fairly warm intercooler for a long time. This effectively moved the safety margin.
This safety margin you are going to be very close to Gary, you just need a real hot day, sit in traffic for a while etc and like the lottery used to say "it could be you"!!!
Best cure is to raise that safety margin. Many cars may run for ages close to the limit, and you\'d never know how close to popping a seal you were.
Regards
Max
A quote from the JapUKMeets Forum regarding water injection
QuoteCorrect mapping does not require water to be injected. Water does not burn. Water causes corrossion. Even Water with 50% methanol alters the burn characterestics detrementally.
There does seem to be lack of rotary mapping experience/info oin the UK simply due to the investment in blown engines required to find the limits with various setups.
IMO ;)
AND you have those fancy ceramic seals don\'t you Gary???
They must help?
Regards
Max
If correct mapping includes operating at lower boost, and assuming that decent fuel is used, then I kind of partly agree Tim.
The rest of the post you quoted from JapUKMeets is pants ;)
"Water does not burn" state the obvious! - but it is very good at absorbing heat!!!
Please take this in the spirit intended :)
Regards
Max
Why did Phil Goriahs car blow up 6 times? Was that due to tuning?:confused:
I have had both my cars over 160 more times than i can remember and not just for a short spurt as at totb.
Yes I witnessed this:D
Max,
Do you connect the motec to the datalogit, have you checked logged readings against readings if you ran the motec separately?
In the pfc if the Air temp sensor is heat soaked it takes alot fuel out, but once you are moving the air going into the engine is cool, therefore you get a leaner condition.
claaizy rx7
are you sure its blown 6 times
:eek:
The motec is connected to my datalogit and has been set up correctly so that the display matches with the logged values.
Yes, I had considered the matter of the air temp sensor in the equation, affecting both fuel correction and ignition timing.
From recollection, does fuel not go up and ignition get retarded with high intake temps? My FCEdit sofware is at home :(
I\'ll have a look tonight.
Regards
Max
The fuel decreases the hotter the intake and yes the ignition is retarded at whatever temp you set it to.
Jason
There should be 2 things happening with a good ECU. Up to a point the speed density equation will reduce fuel to cope with reduced air density. However there should also be maps to richen up in case of excessive intake temperature. This latter is missing in some cases.
Haven\'t looked at the FD but there does appear to be a design flaw with the air temp sensor if it does heat soak badly.
The PFC has 6 points from -30 to +80C, so yes you can richen the high temp.
The sensor is the problem, you have to stop it from heat soaking and to react faster.
Json
I have sort of been following this, in my OWN personal opinion a lot of this is down to the mapping of the cars.
Trolling though the US forums, I came across this new forum on water injection. http://www.turboice.net/forum/
Hopefully this forum will take off, and lots of useful information will be posted on there. Sadly I don’t think much of it will be about rotary engines.
Once the ECU gets replaced on my FD, I will be speaking with Carl (the nice gent who built my engine) to make sure that he is happy with each of the steps on the mapping project.
I have said for a long time that I don’t trust the Apexi as an ECU! I just don’t think it’s as good as people keep rating it. I am using it just to make sure that the engine can be run in properly, even the base map if so rich that it shouldn’t blow up. And then keep the engine running until funds allow for a proper ECU to be installed and mapped. Even might be going for the bench dyno mapping way, but then when re-fitted back in the engine bay it will require further mapping.
Max, although heat is generated by having to much fuel in. My understanding is that it can also work for having to little fuel in! One easy way of checking is to have EGT probes fitted, how many cars do have them? Not many. :(
I know the reason for one of the engine failures, and it didn’t appear to be a mapping problem.
Dan
Reading with interest.
PS. Claaizy, be careful about comments like that unless you can back it up.
Hi Fish :)
Yes, I must get a pair of EGT sensors - one for each rotor....
The beauty of topics like this is that there are so many opinions! You just need to look around on the US forums for that. It would be so easy if everything we read was always correct!
It could be my mapping that caused my pop, but my timing map is a little less aggressive than a stock map to (hopefully) allow for 98 ron fuel as opposed to the 100 it is supposedly mapped for in stock form.
My fuelling according to my O2 sensor was bang on (although I accept that a pair of EGT sensors would have told me if I was lean in one rotor).
Some kind of temperature correction to timing or fuelling may have assisted the failure, hot weather, hot sensors, hot everything! I could throw in another spanner and mention plugs?..........
But I go back to the safety margin issue, which higher octane fuel and WI assist with.
Just moves that danger area further away!
Why don\'t you trust Apexi ECU\'s Fish? Plenty of cars run with it. Who\'ve you been talking to ;)
Regards
Max
Max you know me, I talk to almost everyone. ;) They say its good to talk.
I have never really liked the Apexi, and those that know me know that. I have never kept it secret. They are ok at the fuel and ignition adjustment, but they cannot control boost properly even with an uprated map sensor. Thats why everyone runs a boost controller along side it. Some are using the Apexi unit, some the Blitz, HKS, etc. but it appears that once you change to single turbo setup, it cannot handle it.
I agree with the two EGT sensors, but you could get away with running just one on the rear. As we all know that is the one that runs lean and thus hotter.
Dan
It has blown up 6 times due to crank sensor issues I think, there was some kind of problem with the motech sensor. I just cant believe people would just keep rebuilding a engine and blowing it again, its just claaizy!!
And Mr Fish, why dont you trust the Apexi? :)
Some like McDonalds, some like Burger King. I just dont like Apexi, its a personal choice. ;)
Thanks for the bit about Phil\'s car.
Dan
Couple of notes to think about ( bit short of time as usual)
1. Most turbo\'d road cars do not have a cooling system that can cope with WOT operation for more than about 30 seconds. Mainly because you are unlikely to need more than that on the open road.
2. When you are running twice stock this will become worse.
3. An air-air intercooler is not a good idea for TOTB type applications. An air-water is better with a nice tank of iced brine in the boot. See the Ruf porsche that they used for the ring record or any bonneville racer for examples.
4. with racing you really should drain the water and refill with just water and water wetter. Antifreeze lowers specific heat capacity.
5. The vehicle cooling system becomes critical. Personally I prefer an EWP to the stock water pump as you can run it full chat when idling. Seperate water circuit for the turbo is worth considering. The FMIC WILL reduce the cooling ability of the rad. ( plus all the housing mods to help heat removal). If it were me I might even get the housings tapped to measure local water temp in between the plugs.
6. If the air temp sensor heat soaks then that needs fixing. Easy enough to do.
7. Heat shielding between exhaust and inlet needs addressing. As does airflow past the turbo. Extra fan worth thinking about or some ducting.
8. Twin widebands are very useful. EGT is useful additional info, but really too slow to save you. Problem is the only person who build a WB that you could put pre-turbo is dead.
9. A workable knock detector would be a god send. I am working on it, promise.
10. Higher octane fuel, but looking at the failure mode, its definately heat build up related, as the engine will have passed through 6000RPM at WOT at least 3 times before the big bang.
Once you have looked at all these holistically then the tuning and water injection follow. As you know I am a great believer in WI, even on NA motors. Tuning is not a black art, its being methodical and thinking it through.
Oh and log anything and everything you can.
Hope this helps
Bill
QuoteOriginally posted by claaizy rx7
It has blown up 6 times due to crank sensor issues I think, there was some kind of problem with the motech sensor.
Hmmm...who told you that then? \'I think\' you are rather misinformed...chinese whispers, hey...
QuoteOriginally posted by claaizy rx7
I just cant believe people would just keep rebuilding a engine and blowing it again, its just claaizy!!
Claaizy indeed :bandit
Hi all,
Good thread Max.
I personally think that tuning is the key - hell these engines ran and won the 12hours at Bathurst 4 years running. You can\'t tell me that they are not WOT for long periods of time! :)
What we really need, and I haven\'t been able to find out there on the internet in all these years - is a good reliable source on the following, (I have picked 350 Flywheel Horsepower as it is probably most common - but anything up to 700hp for a 13B should have similar principles applied I would have thought):
So for the 350FWHP turbo rotary...
1. Timing for the Leading plugs (across the rev range)?
2. Timing for the Trailing plugs (across the rev range)?
3. Timing Split between the two (across the rev range)?
4. Primary Fuel injector pulse timing (based on different injector sizes - i.e. flowrates)?
5. Secondary Fuel injector pulse timing?
6. Auxiliary Fuel injector pulse timing?
7. Fuel supply system required? based on horsepower required?
8. Optimum Intake temps? (from reading books like Corky Bells he thinks that things like water injection is doing a job that the intercooler should be doing i.e. the intercooler isn\'t efficient enough).
9. Perfect AFR to aim for across rev range?
10. Perfect EGTs to aim for across rev range?
11. Spark plugs to run based on combustion temps?
12. I\'m sure there are other things - but this should be a start??? We can also look at things like the Timing and AFR on a standard rotary, as we know that it has to be like that for reliability.
The above would really be about getting all the secrets from a good rotary tuner - but there is some good info. out there on the Net. I think we should try and compile what we can here?
The hotter weather would increase the intake charge temps. the knock sensor may not pick this up to retard timing. When you have a good ECU you can do things like retard the ignition based on air intake temps. or have the boost level lowered based on intake temps. etc. - can Apexi do this?
What size wastegate are you running? and what boost? Rotaries need LARGE wastgates to get rid of excess boost efficiently.
One of the main reasons that your engines are popping on high speed runs is because the critical detonation point is at peak torque (around the 6000rpm mark).
More fuel will certainly help cool down the combustion temps. but if you aren\'t adjusting timing along with it then problems can occur.
Afterall, if your EGT\'s are really high then the Apex seal won\'t be far from melting point along with all the forces of it going around at 6000rpm also.
Here is a very good thread on timing etc. from some of the best rotary tuners in the world - well worth the read: http://www.rx7club.com/showthread.php?s=&threadid=101226
.ps I\'ll keep searching around - I know that Ezio from //www.cityperformancecentre.com) would have all these secrets, I\'ll see if he can part with some :)
Hi Glenn,
small point,the cars that raced in the 12 hours at Bathurst had stock power levels.
So what with higher than stock outputs being the ones that are blowing up the engine can and does reach higher stress levels than the Bathurst cars.Generally it could be said stock cars do not keep blowing up.
I am in complete agreement with you that tuning is critical on the modified engines, but so are many other things like fuel,how the car is driven,maintenance,boost control,temperature control of coolent,temperature control of intake charge,injector sizes,fuel pressure both from the pump and regulator,sparkplug quality ................and the list goes on.
On top of this is how well or badly the engine has been built and modified can have a direct effect on how reliable an engine is.
Turbo sizing is also important.
So it is a combination of factors that can cause a problem with engine failure.
It must be said though that there are many high power engines that are still running ok here that have spent days on open pit lane track days so some of us must be doing something right too.
Kind regards
Carl:guinness
Hi Carl!!!
How are you? (I\'ll reply to your email later).
The Bathurst RX-7\'s weren\'t quite standard ;) they had larger exhaust systems, larger intercoolers, and the engines had been rebuilt before each race.
Either way - I know they were running them very rich for reliability.
I know that the RX-7 that Ezio/Alec prepared for one of the races had around 350FWHP - pic. here: (http://www.cityperformancecentre.com/achievements/gtp/gtp02a.jpg).
Yep - the list is endless, further to my previous post - port timing of course will effect ignition/fuel etc. so you could only use the stock ports as a guide.
QuoteOriginally posted by maximtaylor
AND you have those fancy ceramic seals don\'t you Gary???
They must help?
Regards
Max
Thats exactly my point if you want big power you must be spending the money to make it reliable, it would be no good building an engine from second hand parts and slapping on a huge turbo, then complaining when it goes pop.
If the engine is built correctly ported, ceramics, even dowled, how many dowled cars out there? and mapped used the best ecu\'s and maps then the cars will last that much longer.
Also poeple dont ever mention that it a engine has popped after 20-30k that I cocider good if you think what pressures these high perf cars are running, you cant expect a 400-500 bhp car to run as long as your old stock motor.
In Aug we spent 2 days at n/burg and 2 days at spa, at Spa I roughly calculate that I drove a min 200 miles around the track just in 2 days. 200 bloody hard miles, mostly in the 4-6000 rev range. We saw off some bloody fast cars and pushed these cars to there limits most of the time, dont also forget there only 2 rotors with the capacity of 1300cc, seeing off much bigger cars, think of the stress they were under.
I can only put that success down to the engine work of Carl and brilliant map supplied by Ant
So what Boost levels will the Apexi ECU safely handle with standard injectors,twin turbo setup, Performance Exhaust and Intake?
Cheers Gary - my thoughts are that perhaps the ceramic seals are far less likely to warp under severe heat and pressure than the metal type seals.
We already know they can take a lot more knock abuse (although they will explode eventually).
Would it be reasonable to assume that ceramic seals keep there shape and tolerances better under these stresses? Carl????
One more thing Gary, you\'re car is damned quick (I know because I went around Spa on a couple of Banzai laps with you - good fun!), BUT and it is a big but - were you not running 0.9 bar boost at the time? What are you running up to now out of interest?
I started the thread on the assumption that going over 14 psi appears to be the problem area. You were at about 13psi. Within what I would think would be \'safe\' for 97/98 octane.
I Like your hit list Glenn :) each of those topics need\'s it\'s own thread....hope everyone has time on their hands ;)
Regards
Max
Great thread:D - My 1st question is where is this air temp sensor situated, if this is so critical at WOT should this not be addressed when the engine is being tuned?
Like G11ARY and Max I did the Ring and Spa [not quite as quick as Gary - but faster than Max {only cause you were runnin in!}] and had no probs - my rebuilt engine has now done close to 12k and has been brilliant, Im just concerned about the top end mapping and heat issues - Never thought about a heat sheild between inlet manifold and turbo. I have been addressing the cold air charge and I think looking into some form of ducting to the turbo area might improove matters.
My 2 rotors worth:wave
Cool so up to 14psi on a upgraded ECU is quite reasonably safe if everything thing else is working correctly, obviously passing 14 psi you needed bigger injectors, Fuel pump, INtercooler, even Radiator, I can see how a front mount intercooler would interupt air flow to the rad, thats why the VMount Rad and Cooler fitted to Miguel\'s car looks ideal.
Hell since I fixed my car 10 psi seems well quick with the decat much faster then when I bought it , I cant imagine what 14 will feel like let alone passed that.
Max I heard the GT35/40 is at its most efficiant when it runs 18 psi, any plans to map it for that Boost level?, Tim Possingham (Horsepowerinabox) reckons at that boost level you should at least get 450 at the wheels
QuoteOriginally posted by maximtaylor
Would it be reasonable to assume that ceramic seals keep there shape and tolerances better under these stresses? Carl????
Hi Max,
the ceramic can handle detonation much much more than steel seals but they also do not wear and so the seal gaps do not open up as much.They are also lighter than stock seals and stay on the rotor housings at revs and do not skip.
They are better at handling high boost too with it\'s subsequent higher combustion pressures.
Kind regards
Carl
No plans for 18 psi on this engine, 17 tops soon perhaps. I\'ll get a fresh one made up to spec for it next year, hopefully :)
Scared to go beyond 14.5 psi at the moment, hence the thread and why I have had Electric water pump and Water Injection just fitted.
Problem is, experimenting can get damned expensive if engine failures are going to occur along the way.
Go for 1.5 bar Gary, log everything and post your progress ;) don\'t take any notice of Carl screaming \'NO!\'
Regards
Max
QuoteOriginally posted by maximtaylor
Go for 1.5 bar Gary, log everything and post your progress ;) don\'t take any notice of Carl screaming \'NO!\'
Not on this engine but yes on the other in the black one as it is dowelled.
Kind regards
Carl
the car has two boost settings, 1 bar which is what it runs most days, and 1.2 bar.
The only times i have run her at 1.2 bar is once killing a poker turbo (honest he asked for it) and santa pod for the 3 runs and the last half day at SPA. At half a day that must have been equiv to 100 miles.
Only stating what I experiance, as my knowledge is zilch and sould prob shut up.
I might be tempted at 1.5 bar have to see about the map, and what is optimum for t04e ;)
So how much would a rebuilt engine with Ceramic seals and dowelled cost approx Carl?
So where is this air temp sesor situated?
Blitzboy: hope you have an aftermarket ecu:D
14psi is plenty on the twin setup!!
Na no ECU thats why I will only run 10psi for now, hmm Carl\'s Dowelled up and ceramic seals engine sounds tempting!
What are Ianetti\'s going for these days? About £1K-1.5K a set?
A rebuilt, ported, dowelled motor running Ianetti\'s is gonna cost you a good few quid mate - then you need all the hardware to run it safely; start saving!
How are you controlling the 10psi, with de-cat, down pipe and induction you are in danger of boost creep and running lean - re-buildsville:mad:
Hee Hee I thought of that John before fitting the stuff, I fitted a boost gauge first then a dawes device on the wastgate actuator signal pipe, soon as fixed the boost leak it lept to 14psi yikes!
I immediatly stopped the car adjusted the dawes device, it now holds 10 psi after a bit of fiddling, it spikes sometimes at 10.5 in the cold mornings.
20B_BOY are "Ianetti\'s" the make of ceramic seals?
QuoteOriginally posted by BlitzBoy
So how much would a rebuilt engine with Ceramic seals and dowelled cost approx Carl?
Of course it depends on the total spec but around 5 to 6 K which would include porting and new rotor housings and side housings,ceramic apex seals and the like.
This would be a very strong engine.
Kind regards
carl
Oh and I forgot the dowelling would be in this price too.
kind regards
carl
Thats a very good price, you compare that to the skline boys they spend twice that on an engine.
Right must start saving and selling my mother must have that Motor!!
QuoteOriginally posted by 20B_boy
What are Ianetti\'s going for these days? About £1K-1.5K a set?
Hi Rich,
The Iannetti ceramic apex seals are around 1.3k per set at the moment.
Kind regards
carl
dont mean to be dumb but what is porting an engine and what does it do.
cheers
The Guru racing 2-piece eccentric is tempting at this level as well.
I\'m saving up for one at the moment, but to put it in perspective I have less than 7K in the whole westfield and it has a power/weight ratio of a 400HP FD. Top speed wont be much over 140, but with no roof, no doors and bum 4" off the ground, that\'s fast enough. Might take the windscreen off as well :-)
Bill
A lot of the Guru stuff is tempting! eccentric shaft, bullet proof stationary gears etc.
There was good article by them in Zoom or FF\'s a few months back - they are doing some seriously \'cool\' stuff atm :eek:
That eccentric is only about 850quid give or take VAT and stuff.
All depends if I can talk myself out a 12000 RPM engine.
Sob:rolleyes: no one going to tell me where this AIR TEMP SENSOR IS:D
Sorry I do not know where to look for it - would be nice to know though, would assume it is somewhere on the induction side? :confused:
On RX-7 club at the moment where people are claiming well over 100k miles (some over 130k) from an engine, so there must be something dramatically different in the UK.
Personally I think a lot of it is down to the sort of use the car gets, you just have to read the number of posts between here and FDUK about people flooding their cars recently to see how many are used. Even if I\'m just moving my car on the drive it never runs for less than 10-15 minutes (when I got stopped for my Jap plates it was because I had taken the car for a short run to let the car behind mine on the driveway out). Also I think it\'s safe to say cars in the UK spend a much larger percentage of time on boost. In the US the driving environment is long straight roads, where generally people don\'t drive quickly so their cars spend lots of time off-boost.
I\'m actually caught in 2 minds as to what to do with my car, I want it to be a lot quicker than it is, but do wonder if it might be sensible to keep boost down at 0.6 bar and see if I can get the first 100k engine in the UK.
10k so far on street port with Ianettis and 0.6bar on stock twins, stupidly rich Apexi map, Carl midpipe (will email tomorrow night Sir :) ) to go on tomorrow (then a bit of remapping), WI to follow early next year.
When they talk about 100k on the engine, I think they are talking about 100KM, not miles. :(
Also in the US they are just getting into the realms of being caught for speeding at 100mph. We have been doing that for a lot longer. I am not saying they haven’t been doing these speeds, just that they are becoming more common out there.
Dan
What ECUs are people using for the high boost cars ?
Been following this for the last few days (o.k. so only got my car last Saturday) as my mid term plans are to carry on my power addiction (might convert my 208 BHP MX-5 into a pure track day beast for the summer).
I know the Apexi PFC is popular (and cheap), but I don\'t like the idea that it can only monitor knock, not retard the timing in those mapping zones, plus does not retard due to engine temperature (?).
Anyone run an Apexi with a separate knock sensor/retarder (like a J&S) ?
John,
Yes the sensor is underneath the upper intake manifold, in the runners.
Jason
You can make the apexi retard timimg or add fuel if the intake and water temps are too hot, sometimes just retarding the timimg can make the heat issue worse.
You can also control the amount of oil injected into the engine if it gets hot aswell.
It is better to have all these issues sorted on the car so you dont have to compensate in the pfc. ie I have my air temp to start retarding at 40 degrees which is still low, but my car never goes above 28-30 when driven very hard in any weather.
The j&s only does the leading coils!
Jason
Danny,
most Americans wouldn\'t know what a kilometre is let alone how to use one!
Seriously though, they don\'t use the metric system over there so 100k engines have done 100,000 miles
Most of the engines that have done that sort of mileage will not be 3rd gens,even here in the UK it is not unusual for 1st and 2nd gens including turbo\'s to do 100,000 miles and beyond.
Kind regards
Carl
The sceptics can find the thread here (http://www.rx7club.com/showthread.php?s=&threadid=27269) it is in the 3rd gen forum and most are 3rd gen owners.
Once they start modding them they do seem to go through engines like us :o but if run stock quite a few are making big miles.
Still alot on much lower mileage though.
I think that the type of fuel can have an effect too as our fuel up until recently had a higher sulpher content.Also as was said earlier in the States people do much longer jouneys with steady driving than in UK,here it is often alot of stop starting and shorter trips.
Kind regards
Carl
Jason, most of the aftermarket ECU\'s will retard ignition/add fuel as temps change. You can normally adjust what temps it starts adjusting things.
Dan
As we are talking now about stock engines, I feel that most failures are down to lack of propper maintenance. Picture this: Joe public has seen F&F, 2F&F wants an RX - best buyes are from the land of the rising sun - loads of cheap auctions [can buy it cheap]- buyes the car unseen [ not from a recognised dealer] chances are it\'s a dog - arrives in the UK [for very little money] gets the SVA/MOT drives of into the sunset only to find it ends in tears - no or very little servicing car goes pop - people start moaning - asking advice AFTER the event instead of prehaps spending a few more £££\'s and doing it through a dealer. I think you will find most cars go pop shortly after landing rather than the long term cars that have been sorced correctly and looked after.
If we are talking about modded cars - if the work is carried out within the \'comunity\' chances are you will get reliability PROVIDED you stay within the peramiters if you are pushing these limits [going for the big numbers] then I feel we have not got the experience yet to go for them - as captain Kirk said \'To boldly go where no man has been before\' maybe the way forward is to share the knowledge - after all are we not all seeking the same goal?
have to agree with what John says.
When Carl built the engine for the black car, his first words were, its unchartered territory I cant put my hand on my heart on say it will last more than totb but would like to see it last longer. Totally acceptable if your doing sometime totally radical and a first time attempt.
Im comfident that the same engine placed in the yellow car would run for miles. Its all realtive to the amount of stress you put your car through, somewhere in the middle there must be power and reliablity IF its mapped correctly and built to a high standard.
Spend ya money and make your choice.
You will never know the secrets of the top power builders as it is years of time and money that has taught them, and to most its there living. But its nice to see the rotary scene moving forward on mid power cars which I have seen in the last 3 yrs.
When I first went to Rotechniks and had a single turbo conversion it was a rareity now its norm, when I said I wanted 400 bhp most poeple were amazed now its ok.
We have come a long way thanks to forums like this and the peeps that contribute.
Just keep it coming, one day I might even learn something :rollin
I think I have some pretty good feedback on this Thread - can you guys who have lost engines confirm what spark plugs in the Leading and Trailing that you are running?
9\'s for me
Hi Max,
OK I think I have some pretty conclusive information on this for you.
I\'m not saying it will stop engines from popping - but it has gotta help in a big way.
The 9\'s all round are no good for high speed running, they are too warm. You really need to get yourself a set of 11\'s (I think Ant use to run these).
Please check out this Thread on Ausrotary - guys out there have been a great help:
http://ausrotary.dntinternet.com/forums/viewtopic.php?p=182483
Thinking about it - (as RICE RACING has mentioned), I use to actually run 10\'s in the leading and 11\'s in the trailing for my non-turbo RX-2, and 11P\'s all round in my RX-4 racecar.
Problems you may have with the colder plugs is fouling up for running around town etc. - i.e. that is why Mazda puts 7\'s and 9\'s in as standard.
But for racing and high speed runs cold plugs are essential.
Let me know what you think.
Already ahead of you on that one Glenn.
My experience in racing has taught me that.
kind regards
Carl
G\'Day Carl!!!
Where\'s your post then :)
QuoteOriginally posted by Carl
Hi Glenn,
I am in complete agreement with you that tuning is critical on the modified engines, but so are many other things like fuel,how the car is driven,maintenance,boost control,temperature control of coolent,temperature control of intake charge,injector sizes,fuel pressure both from the pump and regulator,sparkplug quality ................and the list goes on.
Here Glenn,
Here is my thoughts that I posted earlier which talk of plugs.
I do not wish to give away all my secrets now do I?
It is not just plugs that are the answer,the whole package is.
Kind regards
Carl
:) no worries, but I think the plugs would be a pretty major thing - given the circumstances of high speed running?
Especially if the engine is fairly new and has a decent map in it etc.
I just can\'t believe that they are that weak (which I have never believed of course).
Max, did this happen to you recently - and how many miles were on the engine?
To be fair the engine had 45k miles on it. Thanks for the plug info, I\'ll look into this a little more.
BTW John, asking where the air temp sensor is - look under the plenum (tricky unless you take it off) and you will see a blue plug which goes into the third chamber back.
I can see mine, but then I don\'t have the rats nest anymore.
Regards
Max
Lo,
Indeed, I have now experimented with 9\'s,11\'s and 11.5\'s all round. 9\'s in my engine were OK to a certain point of boost and mods, 11\'s and 11.5\'s made a nice and required difference.
As Carl says though, cant go giving everything away but in my personal experience and opinion the ignition side (obviously) makes major changes to running/perf. If you modifying you sure need to spend some bucks on plugs, we all know the rotary heat thing so why shouldnt these principles apply to a critical coponent like the plugs? Leads, believe it or not OEM Mazda FD leads when they new are not so bad on resistance, although there are better to be had - again in my experience had some junk from the US claiming to be low resistance, had some amazing leads from Japan that sure were low on resistance! If you cant justify or dont need a walloping ignition modules(s) then just make sure you check all 3 OEM ignition paks as often as is convienient.
Following the main point - tuning, tuning, tuning - and think about the systems and the demands you asking of them, how they effect localised components and the overall package. Yes putting on upgrade x will give you y, *but* how and why does it do what it does, understand this then, then understand the continued affects.
Rgds
Ant
Ant - nice to see you on the forum again! [allthough just as cagey as ever!]
Interested on the spark plug thing, is there such a thing as a compromise - ie: fitting say 9\'s in the trailing and 11 / 11.5 in the leading - my thinking being, having the colder plugs for heavy duty and not so cold plugs for easy starting - a bit like having 7 & 9\'s as standard.
John,
Im still in this game, people know how to find me :) Cagey? Me? Oh pahlease! Ask Carl, Im not cagey :)
I personally noticed no difference when I experimented with say 11.5/11 and 11/10.5 combos. Either in smoothness, seat of the pants power, idle, EGT, etc
I have also never had any starting problems due to running colder plugs, yes idle and warm up are rougher but none of these myth start up issues.
Want to mod to big power, u need colder ranges of plugs.
Rgds
Ant
QuoteOriginally posted by db2boy
I have also never had any starting problems due to running colder plugs, yes idle and warm up are rougher but none of these myth start up issues.
"myth start up issues"??
Dude, how much daily driving did you do, and how many cold mornings did you try and start your FD with 11\'s? Not many \'cause you used the Honda for work...?
My experience of using an FD with 11\'s as a daily driver for 12 months was that it failed to start and required in a couple of instances quite major deflooding during the cold months. Changed to 7s and 9s - never failed to start after a second of cranking....
I totally agree about big power = colder plugs though of course. My car was not the same at WOT with warmer plugs, used to misfire, splutter and cough some times at peak torque which was very unnerving. The sound was as I imagined detonation would sound but as the motor lived to tell the tale and on more than one occassion I guess it wasnt!
As always, in my expierence! No the FD never was a daily driver, but yes I would sometimes take it to customers or to work and yes it did have early morning/late night cold starts. Being a daily driver instead of a stop/start car would surely help it with starts anyway?!?!
Heck that was even with the stupid matchbox battery before I swamped it out to a large Bosch one! In 2 years of running 11 and 11.5\'s I never once had a starting problem or flood problem.
Again though tuning tuning tuning, think about the whole system and process of starting, ignition, fuel, air density, air temp and not just the plug ratings............
Rgds
Ant
QuoteOriginally posted by John Yorke
Ant - nice to see you on the forum again! [allthough just as cagey as ever!]
Interested on the spark plug thing, is there such a thing as a compromise - ie: fitting say 9\'s in the trailing and 11 / 11.5 in the leading - my thinking being, having the colder plugs for heavy duty and not so cold plugs for easy starting - a bit like having 7 & 9\'s as standard.
Hi John,
I could not help noticing that you were considering putting 9s in the trailing and 11\'s in the leading.
DO NOT PUT THEM THIS WAY ROUND!!It could blow your engine up!
The colder plug MUST go in the trailing,ie the 11\'s should be in the trailing plug holes.
If anyone is fitting 7\'s and 9\'s then fit 7\'s in leading and 9\'s in trailing.
Kind regards
Carl
I have several daily drivers, theres a contrdiction, but I do drive a RX daily and never have I had a starting problem unless the engine was on its way out and once I stupidly was in a rush and moved a car turned her straight off. All cars are in diff states of mod and all run dif plugs. Cant see plugs being much of an issue unless serious power for drag or circuit racing if just for daily or weekend driving.
QuoteOriginally posted by db2boy
As always, in my expierence!
"myth start up issues" sounded more like a sweeping statement to me which is why I bothered answering!
No the FD never was a daily driver, but yes I would sometimes take it to customers or to work and yes it did have early morning/late night cold starts.
Yes, "some times" started it in the cold - which I was comparing to EVERY DAY, starting first thing, again after sitting for 9 hours in the cold, then again after sitting for a couple of hours and once more at midnight-1am...
Being a daily driver instead of a stop/start car would surely help it with starts anyway?!?!
You reckon?? I thought it would be the opposite; switch on, sit in traffic, stop, repeat cycle? would this not foul the plugs if any thing?
Heck that was even with the stupid matchbox battery before I swamped it out to a large Bosch one!
I think mine was slightly larger than yours, but not much? :)
In 2 years of running 11 and 11.5\'s I never once had a starting problem or flood problem.
In about 18 months (inc 2 winters) and 25,000 miles I only ever had cold start and/or flooding probs when running 11s...
Again though tuning tuning tuning, think about the whole system and process of starting, ignition, fuel, air density, air temp and not just the plug ratings.............
Dont get me wrong Ant, I hold your rotary tuning skills in the greatest regard (and I love you man!); this is all just MY opinion based upon MY own personal experience!
R.
thing is. If you have a \'serious\' engine, you won\'t worry about keeping several sets of plugs for it and driving to the track on \'street\' plugs then changing to \'race\' plugs is no great problem.
WI should remove the need for such cold plugs, should it not?
Appreciate what you are saying about looking at the whole process and the the importance of good tuning Ant.
Debate rages about what is good tuning as well, just look at the datalogit discussions about split timing for one classic!
Regards
Max
Rich - you are such a twat - love you too man ;-) So how about the ECU start up fuelling being too rich/lean and the start up timing being too adv/rtd for a given plug range - reckon that would affect different plug ranges??
As for the split discussion, a subject in my mind, thoughts and ECU for about a year now - personally I favour split.
Carl, I found T1 = 9, T2 = 11, L1 = 11, L2 = 9 stopped rotor tip chatter.
Rgds
Weeman
mmmmm.... same as Carl then Ant, thats 2-0 so far on split....
I tried 8 for a while, my bottom and ears said engine felt more perky than Mazda\'s 14 or 15, but then again I like to experiment a bit.
How much at boost? 12,10,8 ???. Someone please sacrifice an engine on a dyno to try different split........anyone??? hello?????
Regards
Max
Max,
WI will reduce heat, but in terms of the plug I would not say that it will allow you to run much cooler, as once you have a safety margin you\'ll only end up increasing boost/timing.
I must pull my finger out on the ion sensing, then we can solve the split issue for once and for all.
Bill
Thanks for the advice Carl - trust me to get it back to front! if mixing the plugs has no real effect I will have to learn how to swap out hot plugs:D
What benifits could you expect from fitting an ignition amplifier?
Hi John,
There is a lot of views on this but I think it is only really needed on really high output engines.
Kind regards
Carl
I have been looking about at the Apexi, and it appears that it only decreases power when COOLENT temps are high!!!
It does not appear to measure intake temps and adjust fuelling and ignition maps.
Am I wrong in this? Someone please let me know.
Dan
Pretty sure Ant used to use Datalogit to combat retardation due to air temp \'correction\' at the Pod...?
There are settings to allow for Ignition adjustment against air temp, and (air temp and load).