Car is an MY04 WRX with full decat. Just fitted boost gauge and noticed the folowing:-

Peak boost about 1.1 bar
levels out to 0.9 bar
after 6000rpm boost slowly drops off to 0.7

Is this normal, is the cars standard ECU mapped to do this??

Note to self, fit all gauges whilst car is standard to compare results

 

Didnt think std cars ran full boost upto the redline.

Dipster

 

Hi Austen, I'm suprised it doesn't start dropping off before that. Standard cars always drop off at the top end. You would need a remap to get the best out of the car. On our 03 WRX we are getting 312bhp and that is at 6750

Marc

 

Sounds about right. The standard turbo can't flow enough air to keep boost up at that level.

Solution? Fit bigger turbo, bigger injectors, remap ecu, fiddle with intercooler (either fit STI8/9 or go FMIC or aftermarket), look at bank balance/credit card bill and go "oooh ****".

 

It maybe a bit lower, but at that speed, trying to look at the boost gauge, rev counter and road, things get a bit blurry!!

Ok, i'm not worried now. Its going for a remap in a few weeks so looking forward to that!!! What specs are you running to achieve that?

 

Yup, limits of the small turbo. My car is running a TD04 too, with a manual boost controller, so it's trying to hold the set boost all the way to the redline. It holds the set boost - 1.2 bar - up to around 6k and then tails off to about 0.9 at the redline, so that I guess is the absolute limit of the air it can flow.

 

the boost on my 'out of the box' 05 WRX drops VERY noticably after 6k revs (feels like someone nicked the turbo for a fraction of a second!). If I am pushing her hard only bother to go to late 5s before changing gear.

paul

 

Isn't it also something to do with wastegates etc opening at certain rev/pressure points?