I\'m off to pips tomorrow to finalise my LPG tuning and im wondering what i should expect :mmmm
The car has a stock nikki carb with a impco 300a bolted on top. I have pips stainless exhaust system without any of the emissions stuff.
I\'ve just renewed my dizzy cap, rotor arm and coils for new and pip will be removing the emissions stuff off the engine tomorrow.
The engine is a stock port 12a n/a with 110k miles on the clock.
The LPG is 107-110 ron so makes this interesting :D
Shaun
whats the prize for guessing correctly?
I am going to say 70hp at the hubs :)
Satisfaction :D
Thought the stock setup was more thn that with the emissions on ???
Shaun
I think Mazda were a little optimistic in their figures and it\'s only a guess :)
I will say 100atw :yes
Quote from: BrettI will say 100atw :yes
How can you quote ATW with a hub dyno??????
Because I have no technical basis for my prediction and thought 100 was a nice round number :D
lol, atw is 10% less. Im hoping for about 100bhp at the hubs.
Probably overly optimistic.
Shaun
hummm i reckon about 105 at the hubs :D
ok i will split it 95:chat
Mark
82.........
im still hoping the higher figures :D
Shaun
my 1st gen with a racing beat exhaust and all the emmissions removed made 115 atw\'s on the re worx dyno but that only had 44k miles on it.
I\'m not sure how much you will lose on the gas, my BMW doesnt seem to lose much but its a multipoint seqntial system.
I reckon you should see 110 at the hubs on petrol, maybe 90 - 95 on gas.
good luck tomorrow
PS: I took a stock first gen round the track on the north weald activity day and managed to drift quite well with no power and an open diff , so you will have a great little car when its done.
Yep, the handling is so much fun. Get the same feeling with that as with the FD, just at much lower speeds :D
Can\'t wait to swap all my bushes over and have it running like new !
Hopefully with the gas running higher octain i should see good results :D
Shaun
I will predict 92.453509213bhp ATH\'s :Laugh
Like to be accurate you see :Laugh
The bad news is that my engine is goosed. Pips been tuning today and the best we got was 63.8bhp at the hubs, which is really bad. Plus pip said my diff is knackered ! He got the compression tester out and the car is showing 6.4-6.6 on the front rotor and 4.4-4.6 on the rear rotor.
Not good news ! To be expected from an engine thats done 110k miles !
The next big question is how soon can i get my hands on a 13b :Giggle in the form of a 2nd gen EGI ! It will get rebuilt and ported too before fitted into the car.
Oh and a new diff because pip said thats knackered too !
Shaun
damn it I was nearest :( ... pity about the engine BUT does it drive better now it\'s been sorted that\'s the main thing of tuning ... not the number :)
now can you run a bridgey on LPG ;) (that\'ll get those fuel cost back up again!)
do you run different heat range plugs with gas ? does it burn clean or is there excess carbon if it is overfueled as per petrol ?
Bad news Shaun but i\'m sure you\'ll get it sorted before long. As Mike said do you not fancy a 12a or 13b bridge?
Kevin
Bugger soory to hear that your engine is knackered. I was turning my 12a over the other day and noticed that it was feeling a little \'looser\' than mormal. Might also be looking for a 13b soon enough. :(
top project, good luck with the lpg.
It was run on the same plugs. Pip thought the gas carb was restricting the flow so we did another run minus filter (because there is a bigger filter for the carb which is rated at 450cfm) but it didn\'t help.
Engine could have another 10k life in it, but at least i know that i need to get an engine ready for it !
When the new engine goes in it will be a 13b out of a 2nd gen EGI. Not sure on the porting yet, at least a medium street port thats for sure ! Should be able to use quite a bit of kit off the 12a to make the 13b a easier fit. Its not going to be a 12a because they seem to sustain higher damage and aren\'t usually rebuildable. Plus I\'ll still run it on carbs and minimise the setup as possible.
Kev, the rear axle isn\'t the right one. I need one with vented discs. The PCD changed between yours at 110x4 to mine 114.3x4 and lots of other stuff too !
Mike you where the closest. To be honest it doesn\'t feel greatly different from the petrol setup so the engine hasn\'t changed much. Plus pip got the engine to idle properly, which for a daily driver is worth the session alone.
I have to say the gas is a very good mod, done 85miles in the 1st gen and stopped on the way to pips to fill up at a motorway services. Stuck about 20l in the tank and still had change from a £10 note :D
Shaun
I\'ll check the one thats on the rolling shell Shaun and get back to you if thats the same might be a few days though as works mental.
Kevin
Cheers kev :D
Shaun
as i said on the phone - i have a spare non running 13b in the garage - so we can strip that for any parts you need :D
i see a good project on the horizon :D :D
sorry to hear the engine is tired. Sounds like an opportunity to me!
Mike, Gas is much cleaner burning than petrol, its also somthing like 20 times cleaner than a diesel aswell.
You need a good ignition system with the gas as its so cold, but even gen 1\'s had a superior ignition system compared to most cars. I have to change my plugs every 12k miles on the BMW, i reckong they would last longer withough the gas.
Oh yes, a good project.
Its the intake side that is bugging me at the moment. I\'d like to scrap the nikki as well, but that may mean an efi ida throttle boddy minus the petrol injectors (plumb oil metering into them) and some interesting adapters !
Shaun
Although the nikki may be the beginning of the process !!!!
Shaun
Hows about a decent sized holley???? something with a larger cfm?
Im not after the petrol side of the system at all because of the gas and looking at the holley the impco carb is too tall to sit on top !
Plus the efi throttle body without the fuel rail is about £300 for a twin 50mm !
Shaun
if you just want a throttle why not build plenum to sit on an IDA lower manifold or even the stock 13b lower manifold and use a big single throttle body
Cut out a manifold plate from stainless or alli plate, 2 or 4 runners into a suitably sized plenum (3" or 4" tube? there are calcs to work out ideal volume) then fit another flange onto that for a standard single throttle body off somthing else (scrappy job or Ebay or even an FD one?)
or make and adapter plate and use the whole FD manifold or a TII one
Looking at the holley site there is some interesting throttle bodies as well as carbs. The only real problem is that they don\'t mention what cfm any of them are ! What size should i look for if im thinking of a streetported 13b egi n/a. The gas carb rating is supposed to be 450 with a 14in diameter filter.
The other question is if I go with the ida i may have to run it on 2 smaller gas carbs, one for each barrel.
Blimey all this is going to be crazy. The first thing to do is get the car running on a reasonable 13b with the current intake setup then take it from there with a rebuild, porting and bigger intake.
Shaun
Good point, the FD throttle is only about 50quid 2nd hand but the layout is 3 intakes in a triangle setup. Not sure if its the best option. The single holleys look cool and a custom pickup would be fun.
The current gas carb is a down draft carb, so the FC/FD setup would mean a different carb would be needed. Not sure if a different vapouriser too.
I love to do the ida setup with 2 smaller carbs and run them off one vapouriser and keep the layout as neat as possible. Talk about a cool project !
Shaun
Would something like this be suitable ?
http://cgi.ebay.co.uk/NEW-80mm-Throttle-body-Super-Hi-flow-Nissan-R32-Skyline_W0QQitemZ230118466753QQihZ013QQcategoryZ10386QQrdZ1QQcmdZViewItem
Shaun
You\'re very bad men !!!! got me reading stuff like this :
http://www.rx7club.com/showthread.php?t=199788&highlight=intake+runner+length
Shaun
LoL, that\'s what I was thinking of when I posted about the volume :)
if in doubt look what works for everyone else and adapt it to suit what you want and whats bits you can find :D
I\'ve read the whole 8 pages and to be brutally honest im still confused. The biggest question isn\'t about runner length, its more a case of runner diameter (the thread seems to say that doesn\'t matter as much ???) and plenum diameter and length.
If I went that route i would have something like a custom intake with a 65-70mm throttle body with the gas carb on top.
If i went the ida route, then id buy the stock ida manifold, dual 45mm ida intake and dual gas carbs with one on each throttle barrel with a single vapouriser.
Arrrrrrrgggggghhhhhhhh, questions, too many answers !!!!!!
Shaun
lol, the other big issue is the ausies run turbos with gas and gas conversions here are few and far between !!! Talk about re-writting the book on whats possible !
Shaun
I am pretty sure that mazrech in melbourne , oz, do good quality conversions. Just depends if you want to chase stuff up from overseas? Any reason why you dont want a nice little turbo sitting on the 13b with the lpg?
cheers, michael.
The turbo setup would need alot more work, with an intercooler and supporting mods. Plus I should be able to modify my exhaust to fit the 13b easily too on n/a.
The gas carb i have can be plumbed to work on a turbo without big concerns so may be a future option.
This car is a daily runner so i don\'t want it to be too mental. I\'d be really happy with 200bhp at the fly because it\'ll be used during winter months !
Cheers for the aussie link, will do a search on google :D
Shaun
Would you need a intercooler with just gas shaun as the temps are going to be lower anyway?
Kevin
Thats a good question. The gas is warmed up by the vapouriser so it can aid cooling but it is still cold when its fed into the engine !
Shaun
If not can you utilize the gas to cool the intake charge anyway similar to a nitrous cooler.
Kevin
It should do that anyway :D
Its the intake that will be the most fun (if thats the right word).
The other bits like having a gsl-se sump fitted and swapping the 12a front plate over and installing the 12a dizzy that are the first main jobs. Plus slotting the engine mount to take the longer engine.
Shaun
I\'ve started a new thread to the quandry of a new engine :
http://www.mazdarotaryclub.com/forums/showthread.php?p=377883#post377883
Shaun