Hi folks, had a 3inch turbo back exhaust fitted today on my 2006 impreza sti hawkeye with a high flow 200 cell sports cat. But i think i am having a bit of a problem. Rather than gaining power, i fell like i have lost power. The car doesnt feel as torquey or as powerful as it did like before when i still had the the standard 2.5inch exhaust fitted. Any of you folks able to point out where i've gone wrong here or is it that i am in need of a ecu remap? The car is totally standard beside the exhaust system that i fitted today by the way. Also got a hks ssqv bov im thinking of fitting, should i scrap that idea and just keep the original

 

you have changed quite a significant part. your exhaust gas back pressure will have decreased quite a bit going from 2.5" to 3", and the sports cat will have had the same effect. the ECU is expecting certain values, and now it is receiving values quite different to what it is expecting. very possible you will need a remap. take her to a specialist to get it checked out...

 

If you like the sound of the ssqv then put it on, it won't benefit your car in anyway and the original would be better for your car, but if you like it then, as said, put it on. won't harm your car if you get it remapped after fitting.

You need a remap to sort your car out. here goes nothing:

your turbo has a propellor that is spun by air entering the turbo and also air leaving the engine,(headers/up pipe), because you have upgraded to a 3 inch from a 2.5, pressure in the exhaust system drops and your turbo boosts less/is affected

An example would be blowing through two straws, one is 2.5 cm in diameter and the other 3 cm. which will have more pressure coming out of the end. The answer is the 2.5 by the way.

Anyhow a remap will sort this, and i may be wrong before someone goes crazy at me and sorry for waffling.

 

A turbo back exhaust should not affect spool up and should still net a tiny improvement in power without a remap. Do you have a boost gauge so that you can tell if there is any difference in boost?

 

My main question is have you had a Remap for the change of exhausts, if not youve prob confused the ecu and its taking out timing etc

steve

 

the turbo and oil pressure values look the same as before. i think around about 0.6 or 0.8 kpa and pressure about 1.8 or 2.0kpa while idling with the car hot using defis

 

hi steve, so a remap is definately needed then? which company would you advise on using to remap?

 

remap is needed. duncan@racedynamix or JGM are two reputable mappers that travel to you.

 

As tazz days mate Duncan or JGM ive used Duncan numerous times

Top bloke

Steve

 

Thanks for your replies. Just contacted Simon and Duncan for some rough prices. Can you guys give me a rough guideline as to what i should be expecting to pay for a remap without changing the ecu ?

 

I did the samething, changed from 2.5 to 3, and lost torque low end but made some more top end. To be honest would rather have the 2.5 back on. Just my 2 pence worth

 

Wow, I'm seeing lots of surprising information in this thread.

How does reducing backpressure after the turbo (the purpose of getting a bigger turbo back exhaust) lose you torque anywhere? Someone please explain.

A small change like putting a turbo back exhaust is not out of the bounds of the ECU to compensate for. While there will be gains with a remap, it is not absolutely needed.

ScoobyYau, turbo pressure at full boost should be more like 100kpa, are you reading the correct gauge?

What I think happened is that something was messed with or knocked loose while fitting the exhaust. For example an issue with the oxygen sensor could make the car feel unresponsive and slow off-boost.

I think it would be better to first see a specialist to sort out the issue you are experiencing, then you can have the remap done if you still want more power.

 

Going from a normal cat to a sports cat

Plus removing the 2nd cat should surely require a remap

Prices wise for an open source map

I believe Duncan charges round the 300 Mark

Well worth it in my opinion

But would recommend updated walbro and possibly
3 port boost solenoid

Steve

 

You could give Graham at EngineMapper a call, he is based in Wrexham. His prices are on the website but usually £225 for an opensource map.

http://www.enginemapper.co.uk/

He recently did a good job on my 2006 Hawkeye so I've go no probs passing on the recommendation.


Cheers,

AJS

 

Hi Saiklon, yes the boost reading is normal. As you stated it is reading 1.0-1.5kpa full boost on the defi gauge. The previous readings i mentioned above were for when my car is idling hot.

 

Hi Steve, been in contact with Duncan. He qouted me £350 for the custom remap. Good price compared to Ecutek Now you got me all curious about the whole walbro pump and boost solenoid thing lol. Should i get them done before the remap ?

 

If the car isn't a ppp then it won't come with an uprated fuel pump

So yes would highly recommend it for safeguarding future upgrades

Also Subaru came with standard 2 port solenoid again 3 ports are ideal for future and present mods

Steve

 

Got my car mapped for £285 today by Graham of enginemapper.co.uk in Wrexham. Must say, i am very impressed with his work and thought i would recommend him to you guys. He came all the way down from Wrexham to Caerphilly too ! Top man, sorted out my boosting issues too. Apparently loose boost solenoid hoses. DOH ! >.<