Getting the rex mapped soon, would like 350bhp+ if possible my spec is:
Large street port,
Stock Twins,
Decat,
Kakimoto Regu 92db Exhaust,
K&N style induction kit,
Power FC,
GReddy Style FMIC,
Koyo Style Rad
Rewired Fuel pump,
Stock Injectors
As I have the stock downpipe what is a good amount of boost?
You will find that stock twins don\'t like living with more than 1 bar boost so regardless of your down pipe, theres your boost limit to get it mapped at.
Hope this helps
Gonna struggle for 350 with stock fuelling: need bigger injectors and/ or signficantly higher fuel pressure. Stock downpipe is restrictive too.
Go to 1600 secondaries or 850 primaries, and an update pump and you might get close to 350 at a real push...
you can go to 350bhp on stock fueling, id just advise you up your fuel pressure as it fits 100% duty at 360bhp on stock fuel pressure.
Or like Aubec says put some 850cc secondarys in your primary rail, thats what i did and at the same power i hit 75% injector duty, nice and cheap, they only cost me £30
ive got a stock downpipe as well
You can run more than 1bar but its a sliding scale, the more boost you run the less time the turbos will stay together, there are people running theres up to 20psi but your expecting at any moment for them to pop
At 20PSI the stock tubs will jsut be blowing superheated air - it\'s pretty much pointless.
At a 0.9bar, my relatively new 99 spec twins lasted a whole 6 months.
I\'d really advise you to fit a downpipe - te stock one is a massive bottleneck. With your mods an a downpipe I made 340ish, totally stock fuelling. 94% duty.
With a rewired pump I\'d have thought you\'ll happily make 350 at similar duty.
For the £100 or so of a downpipe, it\'s well worth it. Just don\'t get an eBay one, as they\'re invariably LHD so won\'t clear the column.
not really SiH they will make power at 20psi but like i say, they will blow at anytime, im not advising he does it just that they can go that high.
Id say run around 15psi as thats nice and reliable, anymore than that and your going into unknown territory in terms of life.
i hit 320 at the fly with totally stock fuelling and stock twins at 0.8Bar, that\'s with 92% injector duty though so you\'ll need to do something to the fuel system. at the very least a stronger pump and a decent regulator.
With stock twins/fuelling you will max out the injectors before you get 350hp imo, even if by some tweaking you get 350hp then it will not be a safe and reliable tune.
Get a fpr and an 044 or some bigger injectors if you want 350bhp on twins and maybe buy a second spare set of twins.
Rewiring the fuel pump will help get more out of the system. The stock wiring has bad voltage drops, both on the ground and the power wire side. Here\'s a very useful fuel calculator too. Shows fuel pressure, pump, and injector requirements for estimated power levels. http://www.wannaspeed.com/index.php?main_page=page&id=19&chapter=1
Quote from: kompactor;704771Rewiring the fuel pump will help get more out of the system. The stock wiring has bad voltage drops, both on the ground and the power wire side. Here\'s a very useful fuel calculator too. Shows fuel pressure, pump, and injector requirements for estimated power levels. http://www.wannaspeed.com/index.php?main_page=page&id=19&chapter=1
That\'s based on USBHP though - the exchange rate on them is similar to the £/$ ratio.
It has both flywheel and rear wheel hp. Rwhp should be pretty universal. In any case it shouldn\'t be hard to convert.
unfortunately not, because looking at it assumes that you believe dynojet figures which we all know are false.
For you guys over the border, imagine our power figures are the stuff you see on mustang dynos which are around 15% lower than dynojet
So you take the numbers and reduce it by 15% or whatever. To make it easy just add it to the "drivetrain losses" area.
A stock 93 RX7 is rated in the US at 255 BHP. On the dyno here a healthy stock RX7 would make around 217 or so.
The calculator defaults to a stock 3rd gen RX7. So if anyone knows how much power a stock Rx7 makes on a dyno there, it can be easily adapted.
So say a stock 3rd gen RX7 makes 175 RWHP on the dyno there. Thats 30% from the rated BHP that the calculator defaults to. Under drivetrain loss enter 30% and it\'s now configured. Of course it won\'t be perfect, but it still allows you to quickly compare different setups and get an approximate limit for a given fuel system.
Another way to do it.... is to enter your current fuel setup and manipulate it until it matches your current power. (if known) Then if you\'re planning for more power you can see the ideal fuel system adjustments that may be required.
If you\'re trying to dial the calculator in using stock figures then I would use the default BFSP (0.64), as soon as you are comparing tuned RX7\'s I would change to the 0.62. This is because a stock RX7 is generally much richer then a properly tuned RX7.
actually looking at them figures on that calculator they dont seem that bad, for example i used this
43.5psi fuel pressure
85% inj duty on stock injectors
0.62 BFSP as alot tune a little richer than the stock map on boost
that gets me 365bhp or 310whp which is pretty comparable to what a couple of fds got on reworxs dyno
the only issue i can see is that it says you can get 399bhp on 100% inj duty on stock injectors and stock fuel pressure which you cant do as far as i was aware
Well you wouldn\'t want to run 100% duty. This would mean the injector is held open and would certainly cause injector failure if continued to run like this.
When I did my first single turbo setup is was a t64 on a ported engine and stock fuel system. At 10 psi I saw some peaks of 100% duty on the pfc. (quickly changed to a larger fuel system) But the setup at 10 psi made right around 350 RWHP which is pretty close to 400 flywheel.
Also if you tune richer then the stock map (not sure why you would) you would want to use a higher value BFSP. I\'m referring to the map in the stock ecu, not the base map that comes with the PFC. If I recall correctly the target AFR\'s for the factory map was in the 10\'s in many boost areas. Most of us tuners go for mid 11\'s.
Sounds like you found some values that work pretty close for you though, and .62 is what I usually use for a rotary that\'s been tuned.
well the issue about the 399 was at 11.5afr i already hit 98% injector duty at 15psi of boost on stock twins with a big streetport and made 360bhp flywheel, saying that i was getting high intake temps so i know that will kill a bit of power
but we shall see as ill stick it back on the rollers with my big cooler and 850c primary to see what effects its made
Thanks for all the feedback. I\'ve decided to fit an HKS downpipe. Also I\'m going to put in some 1680cc injectors with a new fuel pump, regulator etc. After this has would 400bhp be out of the question, sticking to a maximum 1 bar boost?
i think you will struggle to hit it with 1bar of boost, probably looking at 1.1bar assuming everything is flowing correct and your streetport flows well
I got the engine ported by Steve Rivetts, He did someones rex with the same porting as mine, he got it dyno\'d at 360bhp on .75 bar boost with a similar setup to mine i\'m hoping that I get good results like that. :wiggle
yeh steve built mine aswell, you have the large port, basically the one slightly smaller than mine.
i know the car he is on about aswell, you may need to get an ignition upgrade around 360bhp, ive got that power graph if you want to have a look at it.
if your staying on the twins or keeping power below 550bhp on a single in the future then just get a hks twin power.
Im not sure if your gonna need one yet, depends on what your stock coils are like.
Also it depends where your having it mapped aswell, you going reworx?
Yeah the graphs would be good, my email is wiggman@hotmail.co.uk I don\'t know whether or not I need the Ignition upgrade. what power is the stock ignition good up to? Also whereabouts can you purchase it? I found one in the Mazda rotary store and that\'s it. If I can get away with it I will but if I need it I need it. Also do you need to map the car again if you decide to do it at a later date after it has already been mapped?
Thanks
Some iridium race plugs (greddy, ngk, HKS) will help with the stock ignition, and upgraded for that matter. The electrode is smaller and allows for a hotter spark with the same amount of voltage. They also last a very long time. Unfortunately they are expensive, ranging between $125-$200 USD per set. (worth it in the long run due to how long they last)
People have made over 500 rwhp with the stock ignition, although not ideal. The biggest issue is when running large amounts of boost, or adding water injection. Of course is also depends on the condition of the stock system too. You would most certainly pick up a bit of power and response by adding an ignition amp.
//www.wannapeed.com has a good price on the twin power systems, they are an awesome company to work with, shipping might be high on international orders though. If you shoot them an email, they can get pretty much anything you need.
EDIT: delete this post, wrong thread
Thanks for the advice, I think I will take it as it comes lol. I\'m getting the car mapped by someone who steve knows, he does it in the passengers seat while i\'m driving. I would prefer to get it on the dyno but I live in Norwich and it\'s a long way to go to get to anywhere decent. I will look for the plugs you mentioned if I need them.
(http://img200.imageshack.us/img200/7849/dyno22509.jpg)
that was the one he will be on about, peaks at 0.9bar and holds 0.8bar
the issue he had for not turning the boost up was the w/i was blowing the spark out, so he will be upgrading to a fmic intercooler instead of trying to get away with the w/i.
since your running a fmic you should be fine, you may need to change your plugs after 360bhp but every car is different, a set of B10egvs are only £20 for a set of 4 so they are a faily cheap change.
Whats the lad whos gonna do your mapping for you?
Thanks for the graph, sorry but what is w/i? Also I can\'t remember the guys name it\'s mark something I believe.
w/i is water injection.
when a turbo compresses air to push into the engine it heats up, this hot air entering the engine makes it easier for the engine to knock(detonation) which blows your engine up.
W/i has to advantages, spraying water into hot air causes the water to evaporate, in doing so it takes alot of the heat out of the air, so colder air equals less chance of knock.
Also if you use enough water it will also mix with the fuel and slow the burn process down inside the combustion chamber.........the slower the burn the less chance of knock, kind of like what higher octane fuel does.
the issue you have is water is very hard to ignite in a combustion chamber which means it can weaken or even blow out your spark causing a loss of power.
this can be overcome by increasing the spark output by adding a ignition booster(like a hks twinpower) and also changing plugs to a colder set(standard plugs cant cope with the extra heat from a tuned engine)
Oh. thanks for the little lesson in water injection lol So I guess a bigger intercooler is better or should I say less troublesome than water injection then? I had a look at those plugs you mentioned. They need gapping I believe. Would it be better to get the iridium ones as someone mentioned that they don\'t last very long.
yeh, getting a bigger intercooler is better, but you have a fmic anyway so you will be fine.
running 1bar of boost is fine without w/i as i run it all day on a crap cooler, when i change to my front mount ill be upping the boost to 1.1bar, the only thing i think will hold me back is ignition which is being sorted promptly.
On the thoughts with spark plugs, its all depending how much you want to spend, you can pay £100 for a set of plugs that last you maybe a year or £20 that might last you 6 months, ive seen them both do massive power.
Yes the £100 are better, im not denying that, but for the extra cost i dont believe they are worth it unless your pushing the envelope or your feeling very flush.
The extra cost is worth it. (And I\'m cheap) Especially worth it if running an ignition amp. I was running egv\'s and after less then 2 months they were toast. Electrode all worn down and rounded. Ignition breakup under boost. Switched to greddy iridiums, have been running the same set for almost 2 years now, electrode hasn\'t worn at all. Maybe some setups can get by with cheap plugs, but definitely not mine.
I bet in a setup like yours the iridiums would last near forever. Saves money in the long run.
I should also mention running 10\'s without an amp can cause the plugs to foul out. Running 7\'s or even 9\'s on a high boost setup can cause a lot of heat buildup that can lead to premature plug wear, or worse a hotspot that could preignite the mixture. Best bet is 10\'s with an amp.
As far as WI and intercoolers, they serve different purposes. While water can reduce iat\'s a bit, especially in preturbo high boost apps, the main reason to run water is to slow and control the burning process. It absolutely kills knock like no other aux injectant.
I run 24 psi (1.65 bar) a cheap china core intercooler, mechanical preturbo water injection, and push over 550 rwhp. My iat\'s never get above 45*c , and my knock is always low 20\'s. The water keeps my engine alive, the cheap intercooler does it\'s job well enough along with the water to keep the ait\'s decent. Nothing fancy but it gets the job done.
Ha ha, thread revival!!!!
Nice read in that stuff. Here comes the hijack
A standard NS system at about .9 bar and a good sized FMIC woundnt need an ignition amp, or is it something that will do no harm and possibly help?