Rb25det Ser2 In 32 Gts4 Issue?!?!?!?!

[WhatBrake]

Hey guys, I have a 32 gts4 that I recently put a RB25DET from a Stagea in and shes trying to be difficult.

Trying to have it boosted up, all supporting mods, straight dump, no cat, cooler etc.

Pretty much its missing hard on any boost above 0.5 bar, but above it also feels like the ecu is taking away bulk power and timing after about 3500rpm, like its trying to pull but literally going no where, no torque, kills it pretty much, then if i persist itl surge a few times (bludgeoning its way through the revs) power comes back on after popping n missing like crazy probably around 5000-5500rpm and it peels hard. so wtf?

I read a previous post from a few years ago on this forum and they talked of afm and afr getting silly after 10psi factory, where the ecu will then retard timing and bust in the fuel safe rich (which i think it could perhaps be, i'm going to wind the boost down to 0.5 bar again and see) even though i want to run at least 0.7-0.9bar cos she peels =P Im pretty sure it's the air flow rate and not the boost directly, however winding the boost down will reduce the volume going past the afm.

Thinking i need an AECU and this should rectify it in a couple months when ive got another $1000 to $14000 free, woo..

I thought originally it could be the afm, so i have a new afm n thats gravy. even have a new fuel pump. pretty sure its rich and retarding and thus i'm running low boost for a little bit, bah. Any more ideas or confirmation would be aces.

Cheers guys!

Edited April 8, 2010 by WhatBrake

[MercuryMotorsport]

It is simply the ECU trying to protect the engine due to all the mods. It pulls the timing out due to the higher airflow volume but can only do so until ~5500rpm mark, which is why it then starts making big power.

You can try retarding the timing on the CAS to see if you can smooth it out, turn the boost down (run wastegate, although with no cat it will run higher boost on wastegate, so putting a cat back into it will actually help until you get the ECU sorted) other than that you will need a tune to solve the problem.

ECU's that you could use are (based on what we use, there are plenty of brands):-

VIPEC

Nistune

Power FC

Autronic

Obviously the above ECU's vary with features, prices, tuning costs and ultimately benefits to the end user so it is important to choose one that will suit you long term. If you want to, I would be more than happy to help make sense of it all via PM or email.

[WhatBrake]

Hi mate that was very helpful. Thank you very much you confirmed my suspicions =) I have a boost controller so i'm going to turn the boost down to 0.5bar for now so it's manageable for the ecu. I will be looking into aftermarket ecu's in the near future, as i have a very free flowing intake and exhaust.

If you could send me an email with some info and pricing on vipec and autronic ecu's that would be great, i'l pm you my email.

Thanks again.

Rhys

[Dose Pipe Sutututu]

I hope you're using a manual ECU as well.