yeah i tottally agree with that

im just saying i dont think the motor will blow

then again im dumping fuel too

 

come on now how hard is it to make an exhaust system that has no pressure but has velocity

i mean thats alot of hours on the flow bench that i dont think anyone spends

there will be back pressure from teh turbo, nothing you can really do but keep heat in

 

Doesn't a turbo charged car act like a NA car until the turbo spools up? With 0 backpressure how good do you think a WRX would launch off the line? I'm not talking about post turbo backpressure.

 

I cut and pasted that from a post of mine in another thread.

Good point.

 

No, until it spools, the turbo is an obstruction in the exhaust system, which means it flows more poorly than a car without a turbo.

Its a theoretical impossibility, because an engine flows different volumes of (exhaust) gas at different RPMs. Basically, you have to tune for optimal performance through a certain rev range. Practically, you aren't going to have an exhaust system with zero backpressure at any rev range, because of emissions and noise regs. Obviously, the only exception would be a track-only car.

 

OK, I did a little research and you are correct about backpressure being bad. I was basing my opinion on misinformation that I’ve read on some of the subie forums. I now understand the difference between backpressure and exhaust gas velocity. In the past I’ve always thought the 2 went hand in hand but they don’t.

Thanks for setting me straight.
Joe

 

I can hear the angels singing now someone who actually went and did some reasearch for themselves, it's amazing! Seriously though, if I came off as being a bit . . . harsh, I apologize, I just get really frustrated about it, because there's so much misinformation out there and so many people who keep spreading it.

 

I understand and share you’re frustration and that is one of the reasons I don’t post on the forums much anymore. For the most part I just do a search and sift through the BS when I have a problem. Unfortunately I ended up being one of the guys that annoy me by spreading misinformation.


jahl7787, have you tested your WG yet and if so did boost hold steady?

 

stock everything on a 2004 2.0 Turbo Wagon i Rebilt the engine for bent valves and
I am getting the same thing flutering of the Presure above 3000rpm to 5000rpm no chek engine lite coming on nothing It Drove me crazy whent and tightend everything and thought that i do something wrong bulding the motor Considering it was my FIRST!!!! Cant belev i could Doubt my self like that, "LAST TIME"! And then i went on the web and found THIS Thread! any way will Try Everything you guys are talking about and let you no what happend THANKS Wouldent No What to do with out a place like this !!!!!!!!!!!!!

 

:? The previous owner had some gages and i cant figure what they were. the wiring is still there but no gages (one white hoes that always hissis and alot of wires i now one goes to the co2 senser in the mid range of the exhast pipe any help would be apreceatid other then that Bare bone Stock configuration 04 Suby Wagon 2.0turbo. Thanks in advance

 

Depending on where it runs the hissing hose might be your problem. Trace it out and find out what it’s tapped into.

 

I think this may be a universal problem with the 02/03 cars. My 02 has been doing this off and on ever since I got it. It did it in stock form as well but to a much lesser extent, almost undetectable. Now that I'm at a cobb stage 2 it's very noticable.

I have noticed that in hot weather it is usually non existant. However, in cool, early morning weather, it's very noticable, very anoying, and it really hinders the performance of the car. I've sent a couple of PM's to Group-s and they think it may be a tuning issue. Just in case though, I'm going to have them do a full diagnostics on the car and then have them dyno tune it. I'll be scheduling this sometime soon. Hopefully the problem gets fixed.

Another problem I think all our 02 cars suffer from is a phantom CEL. It's the misfire code. I got them all the time when totally stock. The techs at the dealer couldn't figure it out. They did say that the car wasn't misfiring. It always ran well even when the CEL came on.

 

The hissing and the blowing all went away and my bost Presure is back to normal! WELL Thanks for the ADVICE MO REX it WAS THE LOOSE White LOOS air pipe hissing. it was improperly installed in the first place, second who ever took the boost monitor out toor it off the thing and left it haning i try to seal it but it was leaking under hood and finaly i just clamped the hoes and WALLA it is Working fine!



Four Stroke SUBY love Suck,Squeeze,Bang,Blow!!!

 

So it was the lead for the boost gauge? Am I reading that correctly?

 

I have this same problem. I just installed a 3" TBE on my 02 wagon, and have been having the same results. I think I might know what the problem is though. I have heard that with a stock ECU, boost cut is at ~17psi. .1 MP is roughly 17 psi. I think that when the ECU sees this boost it cuts fuel which makes the boost fall, then rise like it does.

I went for a drive tonight, and did a 4th gear pull up a hill, and my boost needle was going nuts. .1 then .07 then back up to .1 and so on. The fuel cut idea is the only thing i can think of that would cause such erratic behaviour in the boost like this.


http://www.onlineconversion.com/pressure.htm

That is the website i went to to try and figure out what is going on.

(PS: does anyone know what the MP stands for? Meganewton/meter, Megapascal?)