Counter pressure

Bakke · Post by **Bakke** » Mon Aug 11, 2003 9:32 am

Owkay guys, I'm planning to make a monster from the engine, and the first stap is to get rid of this little problem: When I accelerate, the pedal pushed halfway : everything works fine. revs go up to 6000 and pressure goes to .4bar When I accelerate, the pedal pushed to the metal : everything works fine an d full turbo boost until I reach the 4000rpm. At this point you can feel that the engine has to deal with a counter preessure, and losses its power. It has to work to get over the 5000 and then the engine runs smooth again. Anyone who has an idea where this comes from. I've been thinking about bad injectors who cannot deliver enough fuel or a bad exhaust who creates a counter pressure... Any comments, suggestions or experiences would be appreciated since it's hard to race with a engine that's struggling with itself. Greetz Bakke

Jamo · Post by **Jamo** » Mon Aug 11, 2003 10:31 am

Bakke mate, this is classic limit of the T2 turbo, But first thing first, have you got a cat on the car? If so de-cat it, a bad cat can cause backpressure in the turbine, to the point that the turbine housing cracks. Also check the actuator, you could have boost creep (actuator opening before correct psi level). If possible check for any foreign bodies in the exhaust system that could cause pressure. Other than that i can't think of anything

Bakke · Post by **Bakke** » Mon Aug 11, 2003 10:45 am

The cat isn't the problem. Me and Vince (who I haven't heard lately; is he dead?) checked the cat 2 months ago to find out it was allready empty. Maybe some pieces gat into the exhaust ?? Actuator is working fine since I'm getting full boost ... please take the quiz again <img src=http://www.ezboard.com/intl/aenglish/im ... s/roll.gif ALT=":rollin"> Greetz Bakke

dragon · Post by **dragon** » Mon Aug 11, 2003 10:56 am

Does your car have the lambda sensor in the deceased cat? could it give spurious readings at full throttle? Is it a standard exhaust, routed through the normal path under the car - it's possible you're generating excess backpressure if someone's fitted the exhaust with more bends in for example? - Perhaps it's something just as simple as it needs a professional injector clean/engine clean and tune?   1995 480 Turbo, Flame Red Metallic, Jacquard/Leather

Jamo · Post by **Jamo** » Mon Aug 11, 2003 11:51 am

I know what you mean about Vin Bakke, he's dropped of the face of the earth!!! Erm this is one quiz i dont think i'll get top marks on!

Bakke · Post by **Bakke** » Mon Aug 11, 2003 12:35 pm

Tried the injector cleaner, but it had no effect on it. The exhaust is still the original one. I even too kit to my dealer. The car rested there for 2 days, and the answer I got when I went to pick it up was : search it for yourself, we can't find it fast and you're a handy man. It will save you money if you search it yourself. They checked the compression, fuel pressure, ignition. All was ok. Maybe I'm really pushing the T2turbo over it's limits, but that's because I'm not satisfied over it's power. My mum drives a 160hp 16 valve mazda MX 5, her friend drives a mercedes slk compressor, 2 good friends drive Golfs with engine swaps to a 1.8 16 valve from the corrado, anotherone drives a clio williams, ... that's the neighbourhood where I live in. Fast and Furious is my daily life

Bakke · Post by **Bakke** » Mon Aug 11, 2003 12:40 pm

Ow yeah, I forgot the golf R32, Bora 4 motion 150hp, corsa sport and the bmw M3 of my other neighbours ... and today I heard another friend is planning to buy a focus ... Rs <img src=http://www.ezboard.com/intl/aenglish/im ... ns/eek.gif ALT=":eek">

dbsvolvos · Post by **dbsvolvos** » Mon Aug 11, 2003 3:06 pm

if the boost isnt dropping off , whats the prob ? , perhaps you have a flat spot caused by faulty sensors etc , try having the injectors professionally cleaned . WHat boost are you running? perhaps you have an air leak , what about the fuel pressure regulator , lots of things could be accounted for . i think its just a figment of your imagination , there is a slight flat spot at that point , but there isnt if youve got a preformance cam <img src=http://www.ezboard.com/intl/aenglish/im ... /happy.gif ALT=":D"> <a href="http://www.dbsmotorsport.co.uk" target="_blank"> <img src="http://homepage.ntlworld.com/mj.slater/DBSsig1.gif" border="0"> </a>

Jamo · Post by **Jamo** » Mon Aug 11, 2003 5:13 pm

Heheheh, i hope to second the motion about the cam. Almost there just some "other" performance bits and pieces to go on the motor. Can't wait till megasquirt arrives and then the circle of power will be complete (well till i can get a chipped ecu that is!)

ravennexus · Post by **ravennexus** » Wed Aug 13, 2003 7:24 pm

i was having this problem on my 740. till i pulled out the stock airbox and shove in a nice big K&N cone. <a href="http://www.pbase.com/image/20320285.">w ...  and yes i need to make a bracket to hold the air mass meter. now it pulls like crazy till it hit the limiter at 90MPH in 3rd. snaps you back into the seat in 2nd. and the intake roar is soo cool

Bakke · Post by **Bakke** » Thu Aug 14, 2003 8:27 am

Well, I've tried to put in an air cone, and the engine was totally confused. Bad idling, no torque, nothing. Everything was just worse , so I quickly putted in the old airfilter. Greetz Bakke

Volvo 480 Club Europe

Counter pressure

Counter pressure

You've found the Turbo Limit

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cone filter

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