Boost dropping off so in turn Power and torque dropping off in a major way after 5k, i have persistantly had this problem with above 5k boost for nearly a year now but as this has been the first dyno run which i understandably wasnt too thrilled about.

229 bhp im gutted, my old 1.8 itr had 200bhp on the rollers

I have changed the intake pipes to solid type and pressure chamber check valves, car is bone standard except hks filters and cooling plate and a nur spec backbox.

Boost on first turbo is excellent, second is **** as per graph below

Someone must have had this problem before please help me out, otherwise its a long 600 mile round trip drive to jimmys who rebuilt the engine and turbos 6k ago.

rotary experts HELP !!!!!!

 

looks to me maybe waste gate actuators, or a major boost leak somewhere. Probably on the rats nest, obviously. was there any knock or anything where the power started to fall? it could be foul plugs as well.

 

Plugs were only changed 2k ago and there wasnt any knock or anything, Boost is strong and constant on first turbo so if it was a leak i would expect to see problems on the primary too?.

the car is stock, stock ecu etc.

 

Looking at the dyno I see a big push in HP above 4500. That means your secondary is probably pumping out power fine, at least for part of the RPM range.

What's your boost pattern?

Dave

 

What kind of dyno was this pull conducted on?

I have noticed a marked difference in the majority of dyno's used in the UK (Australian made - Dyno Dynamics Dyno) compared to what is used in the states (Dynojet and Dynopack Dyno's).

The Dyno Dynamics unit will show power readings anywhere from 15%-18% lower than its American counterparts.

If this is the case than you would be making about 270bhp (when you say bhp, are you referencing "Brake" or "Base"?) which is not bad for a nearly stock application.

 

Boost pattern is 0.8 - 0.6 - 0.8 - 0.5 sorry but my gauge is in bar.

i can see the boost definately dropping off after 5k rpm and it feels flat to redline, all other fd's i have been in hold solid boost to redline.

I also have faith in the dyno as the other cars on the day laid down good figures i.e the NA honda vtecs and starlet turbos all getting very accurate figures.

 

Do you know that you cat is not partially clogged?

 

Cat looks near new. I bought a spare when going down this route but when i came to fit, the one already on the car looked in far better condition than the used one i had bought.

So believe the cat to be fine, no rattles nothing.

 

You are experiencing fuel cut. Get rid of your stock ECU and you should be able to hold .8bar through redline (the stock ECU will cut fuel at 11.3psi of boost @ 5500rpms).

My question to the type of dyno was not to say it wasn't functioning properly. Simply saying that different brands will return with different numbers. Knowing the type of dyno your numbers are coming from makes a big difference. Especially if you are trying to compare your power output with cars measured to a different scale.

Aka, I have no problem putting down 325rwhp at 1.1bar (16psi) on the dyno. I know that I'm making 370-383rwhp when compared to the average American number... Do you see the point I was trying to make? 229 could very well be a good number, all things considered..

 

So the only power mods to the car are - intake pipes and hks filters, cooling plate = intercooler?, and a catback from Blitz.

They didn't have pre-cats on the european cars did they? Any block off plates installed for anything?

Tim

 

If you said it was "gutted" didn't that mean there were no cats?

Dave

 

The cooling plate is from R magic and is just a sheet of metal to flow air and not an intercooler the car is stock except

hks mushroom filters
blitz nur spec back box

The cat is still in place but it doesnt have a cat in the downpipe (pre-cat)
It is on the stock ecu.

if its fuel cut how do i turn the boost down to stop this then?

 

I don't think there is anything wrong with your car. Maybe just a slightly stingy dyno. I don't think you are hitting fuel cut either.

As suggested by others, get a boost controller, and keep it under 11 psi to keep your engine safe.

 

English people say they are 'gutted' when they are upset over something. As in, I missed the latest episode of Eastenders last night - I'm gutted.