Further Tuning advice

[Jay-pan]

Hi guys, just been to a rolling road to have the car checked out to see if its running okay.

When on the rollers it produced 180hp/160ftlb at 0.7bar of boost. Which to me seems very low but was told theres a 20-30% transmission loss also had a boost leak around the intake manifold. Also was told I'm running lean 12-13 which is the big issue. But they said its running spot on with no flat spots and produced a perfect curve graph starting at 2200 - 6500 where it dropped off.

So far my mods consist of

HKS GT RS TURBO
HKS Adjustable Actuator (No standard boost control unit)
Tubular Manifold
555cc Nismo Injectors
Uprated fuel pump (Don't no make yet)
HKS 3" down pipe
HKS RSK air filter
2.6" Nismo PRO-Spec exhaust with cat
Z32 MAF sensor
Oil cooler and relocation kit
Standard BOV
Standard FMIC
Standard boost (0.7)

To be fitted

HKS SSQV
Japspeed FMIC

Just wondered if anyone can help with what to do next to make it safe? and also what kind of management could i be running?

Checked the ECU which is standard but has two wires coming from the plug which have a connector on just lying in the footwell (white and Blue) so could it be chipped? or what other options are there?

 

[Jay-pan]

Just worked it out with the 30% added on for transmission loss the figures are 234hp/208ftlb.

 

[Jay]

30% transmission loss? that is a bit high! i would say nearer 15%. even 4wd should see only 25% or so. also i would say you have an ecu upgrade/chip such as NIStune, simply because with a z32afm the car would run poorly (but with 70bhp less than standard, i would want to know why as with the spec quoted i would expect to see nearer to 300bhp)

something is not right here. also the fmic is not standard as the s15 has a wing mounted i/c from the factory. who did you take it to for the rolling road? did they know what they were doing? if this was my car i would want a good mapper to look at it and see what was going on.

 

[Nickichi]

seems low, maybe its the boost leak doing it but i think u got some problems with that spec list, should be more powerful

just FYI when I had mine first time on a Dyno and was still stock it was producing 238bhp @ the fly and 199bhp @ the wheels, peak was @ 6857rpm

with a 3inch exhaust, decat & apexi filter it put it back to stock output @ 245 bhp on the flywheel (although i think it should have been higher, roller was slipping on the tyres)

 

[Jay-pan]

Sorry meant WMIC i currently have, yer i thought it was low as well. Well i am still running standard boost, very restricted exhaust goes from 3' down pipe to a 2.6" exhaust with cat and centre box.

The boost leak seems that it could of let a lot out, its the standard WMIC pipe that joins to the intake manifold you could squeeze it and it would open up (jubilee clip seems to have given up).

Also how big of an impact can lean fuel have part from blowing my engine up, i mean more in terms of power loss? I always run it on Tesco99.

I took it to Viezu good lads and they told me I am probably better going to Horsham Developments, only went to this place as it was 30quid for 3 runs on a rolling road day.

Jay as you say i could possibly have a NIStune chip, is it a simple case of going to say Horsham Developments and they can tweak it right, wanted to get it all sorted out with say the exhaust and FMIC before i started mapping.

Also even though i have got the above mods if the fuel injectors havnt been calibrated or the boost hasn't been adjusted could i just basically be running like stock, seems to me the mods have just been bolted on and a light tweak to get the MAF sensor running properly and thats it.

Oh and thanks for your help guys appreciate it

 

[Jay]

get it to a mapper who knows their stuff. horsham are good as are several others. sort the i/c and exhaust first, then soon as poss take it in. i wouldnt want to run the car much until i knew all was safe. if the 180bhp figure is infact a whp figure then it may not be so bad (if still a little low). i would suggest it not a simple case of tweaking, but more a case of a full mapping session to get everything right, so a phone call to h-dev to get a price first and any advice would be adviseable. before the mapping, fresh oil and new spark plugs would be beneficial too.

 

[Auss15]

The mod list is a bit all over the shop, you have a GTRS/stronger actuator/ high flow manifold on and are running stock sidemount intercooler and 2.5" exhaust.

No wonder its leaning out even at .7 bar

It's just not a case of detuning the injectors and running low boost to run it like stock, the bigger injectors run a different flow signal then the stock

That turbo is good for 380-400HP, but you will need a full 3"exhaust, 740cc injectors for good flow in the top end and a Nistune to get your AFR's right and good power which that turbo will yield. At the moment your'e only using about 40% of that turbo's capability.

 

[Jay-pan]

Its getting there sorting it out now i have a feeling a few mods were removed as there looks like a FMIC was once fitted, but i got a FMIC which i will be fitting this weekend followed by a 3" exhaust. Im looking for around 340bhp mark but don't want to go over 1.2bar. So you saying that the 555cc injectors won't be able to cope if i was aiming for 340bhp? i only thought 740cc were for big high end power say 600bhp+ my friend is running 465bhp on 550cc injectors in his GTO.

Also would the leaning out be down to being very restrictive?

I want to get the mod list spot on so then i can take it to the mappers and have it set up.

 

[DeanS15]

740's give you a big margin to play with, and will happily run 350hp without pulling any real duty, on a gtrs at 1.2 bar I think you'd be lucky to see 340 at 1.2 bar, best way is to fit an updated head gasket and studs and then you can run more boost safely to make the power

 

[Auss15]

Im running a 2871R, 1.31Bar of boost, and 335hp at the rears. At present I have Nismo 555's fitted and have been noticing particularly at Track Days injector duty of 100%.

I took it off to the tuners and he diagnosed it as not enough fuel from 6000rpm to rev limiter. He said to be on the safe side and to stop it leaning out I would be better served by 740's. The 555's were ok while I had the stock T28 but with the 2871R and higher boost they were at their limit.

 

[mattyb]

your friend will be able to run more power with the same size injectors because he has six of them obviously you only have 4. you could do 340 on 550s but the injectors will be high in there duty cycle so 740s are much better.

 

[Jay-pan]

Ah i see, guess injectors as well then. How much do second hand 555cc sell for? What power can u safely run on 555cc injectors?

 

[S15_SAM]

555 are 250-400 quid really, the same pricd as 740's. So go with them.

 

[jib136]

james with mittos old s15 is now running 355bhp and 360ft torque on 555's with 85 duty

greg is the man!

 

[jib136]

Im running a 2871R, 1.31Bar of boost, and 335hp at the rears. At present I have Nismo 555's fitted and have been noticing particularly at Track Days injector duty of 100%.

I took it off to the tuners and he diagnosed it as not enough fuel from 6000rpm to rev limiter. He said to be on the safe side and to stop it leaning out I would be better served by 740's. The 555's were ok while I had the stock T28 but with the 2871R and higher boost they were at their limit.

have a you got a fuel pressure regulater fitted?

 

[Auss15]

have a you got a fuel pressure regulater fitted?

Yes, adjustable.

 

[jib136]

strange that there on there limit? as james's s15 is pushing 355bhp with injector of only 85% and thats on 555s?

 

[Jay-pan]

strange that there on there limit? as james's s15 is pushing 355bhp with injector of only 85% and thats on 555s?

What else has been done? I'm not looking for anything above 350bhp atm so if there running fine at 355 i may just give them a go.

 

[jib136]

555's should be plenty just make sure its taken to a good mapper and its got a fuel pressure regulater.

im running td05-18g turbo, nismo 555's and a z32 (plus basic mods) and mines been mapped to 320bhp.
its going back to greg at proper tuner in a month or so with a fuel pressure regulater, hardwired pump and a new fuel filter and he said it should around the same as james's (355bhp)

i can let you know when ive got the car back

 

[Jay-pan]

Ah okay, so going to need a fuel pressure regulator? what company is this Greg working for? Local to Midlands?