Decat pipe gains

[Paul C]

Has anyone done a dyno run since fitting de-cat pipe and recorded any noticable gains. On n/a Bmw's low down torque was sacrifced for a bit more mid range power. I have heard that it is more benefical for turbos to de-cat the system and was wondering if anyone had recorded there bhp gain from doing it.Thanks Paul

[Kenneth]

Has anyone done a dyno run since fitting de-cat pipe and recorded any noticable gains. On n/a Bmw's low down torque was sacrifced for a bit more mid range power. I have heard that it is more benefical for turbos to de-cat the system and was wondering if anyone had recorded there bhp gain from doing it.Thanks Paul

NZ dyno day results basically showed that they do squat. if you want power gains, just put boost up a couple of psi and you will get much more than a decat.

However a full exaust system will do wonders.

[Wodjno]

Decat to a Standard car will make a miniscule difference.. :thinking:

Once you start running higher boost levels it makes a difference:happy:

Seems to give you a bit more grunt of the mark in the lower gears, but loses you some tourque further up the speed scale :inquisiti

[Kieran]

Decat to a Standard car will make a miniscule difference.. :thinking:

Seems to give you a bit more grunt of the mark in the lower gears, but loses you some tourque further up the speed scale :inquisiti

That's weird - I noticed the opposite - re-fitting the cat has given me more part-throttle and low/mid grunt, but once you get past 4000 rpm, you can certainly feel that the turbos are being pegged back.:inquisiti

I do agree that on a standard car, there's not much difference - it is best combined with other breathing modifications.

[ritch_w]

what difference would a decat make on a standard engine, but with a HKZ cat back system and HKS induction filter?

[bradc]

ritch, probably a little more than on a normal car, due to having less restriction in the exhaust system.

Increasing the boost is still the best mod though :)

[Wodjno]

That's weird - I noticed the opposite - re-fitting the cat has given me more part-throttle and low/mid grunt, but once you get past 4000 rpm, you can certainly feel that the turbos are being pegged back.:inquisiti

I do agree that on a standard car, there's not much difference - it is best combined with other breathing modifications.

Can you remember that far back Kieran :speechles

You mean you've been driving your car. :inquisiti

[WildCards]

low down torque was sacrifced for a bit more mid range power

That's exactly what i've noticed since fitting mine.

[Twpsin]

ritch, probably a little more than on a normal car, due to having less restriction in the exhaust system.

Increasing the boost is still the best mod though :)

What boost pressure can the cars safely take?

[Paul C]

My project over next few months:-

Atf Fluid change- hopefully friday

Decat pipe-Im a tight wad trying to maintane cat just for MOT

Air Filter-Probably just replace panel filter for more breathable type

Exhaust Upgrade-Good airflow/not too loud

Greddy Ultimate ecu-If possibble to fit to vr4,i will use its 2 states of map.

1 economy setting (if one exists)
2 Tuned settings for bit more fun

As i understand it is possible tohave 2 maps that are switchable, still researching this.
I think this lot will do for a start and i am very impatient so might happen sooner than i think.

[Wodjno]

Greddy Ultimate ecu-If possibble to fit to vr4,i will use its 2 states of map.

1 economy setting (if one exists)
2 Tuned settings for bit more fun

As i understand it is possible tohave 2 maps that are switchable, still researching this.
I think this lot will do for a start and i am very impatient so might happen sooner than i think.

The amount of Maps you can have is Infinite.

[bradc]

Twpsin, with the stock turbos you will be unable to hold more than about 12psi the whole way through the rev range, some people run theirs peaking at about 15psi, and dropping down to 12psi a little later on.

Paul C, you can have two maps, but I'm not sure if you can switch between them on the fly, you might want to check with Valmes, he would know best.

[Twpsin]

Twpsin, with the stock turbos you will be unable to hold more than about 12psi the whole way through the rev range, some people run theirs peaking at about 15psi, and dropping down to 12psi a little later on.

Thanks for that Bradc I take it then that you can not frig the standard turbos to give a high boost all the time. You just have to live with a peak and 12psi constant.

well I suppose I will just have to live with that

[bradc]

You can increase the boost a lot in the mid range which will give you a large increase in mid range torque.