Factory gc8 making 188kw atw help!

[2nd5un]

Hi guys, have an issue with my 98 v4 sti type r. I have had the motor rebuilt for a second time in 2500km because it's detonating. The car is factory execpt for an air filter and turbo back exhaust which have been on the car for around 4 years. 

The car has just been dynoed and was detonating but surprisingly made 188kw which is quite high, around 30kw more than expected.

The ecu should be a 6s and has an orange afm and yellow 440cc injectors so all factory, also runs factory 1.1 bar boost on the vf24.

The tuner recommends de-tuning the factory ecu to stop the detonation but I'm sceptical this is the underlying issue.

 

can anyone please give me some insight into what might cause my car to run so much power or whether this is a normal power level or even why it's detonating now after the rebuild but seemed fine for the last 90.000km?

 

 

[Guest]

Who was the tuner? Was it rebuilt with higher compression pistons or thinner headgaskets?

[GC8E2DD]

Factory ECU should be a 75. Mine showed roughly 1.1 bar on the VF24 for years, although I never had it dyno'ed.

[2nd5un]

Yes sorry it probably is 75 I haven't actually pulled the kick plate off to check. As for the tuner I'd rather not say, I have nothing against the tuner, I just wish to seek others advise. As far as the pistons go they should be the same as the factory ones, and the head gaskets I'm unsure, I only have the part numbers, they were picked out of a book at the engine rebuilders. I'm assuming your implying higher compression then factory could be the cause of the power level and det 

Edited January 17, 2017 by 2nd5un

[Guest]

Not trying to discredit the tuner. Interesting that they would do a full power run tho if it had det. Normally they would lift off. 

 

Yes it is something to consider as its effectively stock in all other regards.

[94 Leone]

Run lower temp plugs. Det could be fuel related. Admittedly 188kw isn't entirely unexpected, especially for a fresh engine

[pedro]

As evowrx said..

Not a lot of things modified except rebuild..

Check compression ratio calculations with builder..

188wkw is about right for this engine..

[pl0x]

I wouldn't be hard driving or doing power runs with any signs of DET.

Lower boost, up fuel pressure or get a real computer and get it tuned. There was a g4 storm on facebook for $850 yesterday.

[2nd5un]

Thanks for the reply everyone. I have had a report from the tuner. In his analysis he claims the injectors may be maxed out @190 wkw, they are 440cc yellows and have been flow tested. Does anyone know whether this is likely?

 

afr under boost is lambda .7 (rich) up until 6100rpm where it runs lean .92 lambda by 7500 rpm. What do you guys make of this do you have any ideas? Once again the only mods are turbo back exhaust and pod filter.

The tuner doesn't actually know what's causing this, his "possibilities" are:

-injectors maxed

-rom file in ecu edited

-20 year old ecu failing

 

 

[DacerX]

im getting 197kw on a stock v4 engine running 1.3 bar on a vf24 but i do have a link but still on 440cc injectors

[Guest]

What fuel pump and reg are you running?

[2nd5un]

The fuel pump is a replacement one, I thinks it's universal but not a Walbro just a generic $60 one. the tuner said it's keeping up with demand just. And the reg is just the factory one.

In his report he says the lean situation is consistent with a substandard fuelling system but he's basically put it down to maxed injectors and says the lean top end is not down to the fuel pump.

[Guest]

Id be swapping the fuel pump for a walbro or aem genuine type regardless. 

[gotasuby]

What is the duty cycle? Tuner have a scanner that you can plug in and check data?

 

That is getting very lean up top

[2nd5un]

I'm not sure of the duty cycle etc. I have asked for these details. The ecu is factory so I'm not sure the tuner can get that information. I have talked to another local tuner who seem really helpful and I'm going to take the car in there and see if they can sort it. It could just be down to the pump not supplying enough pressure up top or fuel filter is clogged up, hopefully these other guys will be more helpful and sort it. Cheers for the replies I'll let ya know what the outcome is. 

[pl0x]

On 1/21/2017 at 7:48 AM, evowrx said:

Id be swapping the fuel pump for a walbro or aem genuine type regardless. 

This, and do the fuel pump relay mod.

 

I've run 220wkw+ on two separate cars with yellows

[Guest]

54 minutes ago, pl0x said:

This, and do the fuel pump relay mod.

 

I've run 220wkw+ on two separate cars with yellows

 

Yep 227wkw here on p2 yellows.

[GC8E2DD]

227 was decapped?

[Guest]

30 minutes ago, GC8E2DD said:

227 was decapped?

 

Nope stock p2 yellow side feeds in split factory rails with external fpr and walbro. Rolling road at pbms when gcp was in the building.

[94 Leone]

just a question- when was the last time the fuel filter was changed?

[2nd5un]

It was changed about 2 years ago. It should still be good

[2nd5un]

Thanks guys for the replies. It appears the reason for the engine failure was...... a dirty airflow meter!!! The voltage wasn't correct.