Is this guy full of it?

[Ecstacyraver]

Well, I was going to take everyones advice about getting a testpipe on my car.

I run a stock 2.5 exhaust on my laser, with no muffler, and when i told my local mechanic i wanted a test pipe, he said: "If you run a testpipe, no cat, and a free flowing muffler, you'r gonna blow your valves over time and your car will knock."
He said there WON'T BE ENOUGH PREASSURE

Then he tried to sell me a cat-back.

Should i punch him the face or is he right?

 

[GRNDSM]

Total BS... Turbo cars do not need any "back pressure"

But there is one valid concern, if your wastegate does not have enough capacity, you might end up with boost creep. I have seen it as high as 26 psi (did not take it any farther for fear of destroying the motor). So free flowing exhaust can be a problem.


It is also going to be VERY NOISY

 

[BatmanGSX]

He is wrong. The turbo provides all the backpressure you need. After that the less exhaust you have the better. People used to tell stories about sucking cold air back into the engine right when you shut it down, the rapid change in temperature was supposed to warp the exhaust valves or something. Sounds plausable but not very practical. On a turbo car this would not apply.

 

[Ecstacyraver]

my car is a nonturbo though. and he knew that. So should i hit him REALLY hard?

 

[BatmanGSX]

If it's a non turbo then he is partially right. In theory what he is talking about is possible. Did you not read what I said before or what?

 

[gst_spyder]

Do you have a stock exhaust or a 2.5" exhaust?

Mario

 

[TurboSpoolinIns]

the only concern would be if u totally took off the downpipe and catback which could lead to your turbo blowing up..

 

[Ecstacyraver]

Originally posted by gst_spyder
Do you have a stock exhaust or a 2.5" exhaust?

Mario

stock, sorry

 

[gstspyder1998]

Originally posted by GRNDSM
Total BS... Turbo cars do not need any "back pressure"

But there is one valid concern, if your wastegate does not have enough capacity, you might end up with boost creep. I have seen it as high as 26 psi (did not take it any farther for fear of destroying the motor). So free flowing exhaust can be a problem.


It is also going to be VERY NOISY

I'm not sure how loud it is for the 1G's but I have my cat taken out and I'm still using the stock exhaust system and it's not that loud at all.

 

[BatmanGSX]

Originally posted by TurboSpoolinIns
the only concern would be if u totally took off the downpipe and catback which could lead to your turbo blowing up..

Can you explain the physics behind this or are you talking out of your ass?

 

[psyjoniz]

took my cat out and added a cat-back n1 - its... loud

my car is also non-turbo - is there anything i should know about the seals screwin up? i've never heard of this happening. the piping is 2.5" (outer dia) all the way back.

 

[Ecstacyraver]

hmm...
So in theory this could happen to me..
Is there any way to prevent it besides not doing it?

there is a big drag this saturday and i need the extra horses....

 

[Formz]

Originally posted by BatmanGSX


Can you explain the physics behind this or are you talking out of your ass?

That's what I'd like to know haha

 

[Dj Eclipse]

Originally posted by BatmanGSX


Can you explain the physics behind this or are you talking out of your ass?

I would have to say it is his ass talking.

I gained 3 mph from going from the stock exhaust to removing the exhaust after the o2 housing. This is about 30hp...

 

[venom2097]

Originally posted by Dj Eclipse


I gained 3 mph from going from the stock exhaust to removing the exhaust after the o2 housing. This is about 30hp...

30hp or 15% on a 210hp turbo
I think that is a bit much unless you have a 300lb exhust system.
I'm not sayin it's impossible, but 30hp?
What you did most likly made the turbo to spool faster, by removing the restrictive exhust.

 

[Formz]

Originally posted by venom2097


30hp or 15% on a 210hp turbo
I think that is a bit much unless you have a 300lb exhust system.
I'm not sayin it's impossible, but 30hp?
What you did most likly made the turbo to spool faster, by removing the restrictive exhust.

Import tuner grabbed 26whp on a 2g GST by replaced the stock cat with a test pipe. (had a 2.5" DP and 3" TP back on already)

So 30hp is a conservative figure.

 

[Dj Eclipse]

Originally posted by venom2097


30hp or 15% on a 210hp turbo
I think that is a bit much unless you have a 300lb exhust system.
I'm not sayin it's impossible, but 30hp?
What you did most likly made the turbo to spool faster, by removing the restrictive exhust.

Why is everyone on this board so IGNORANT?

First, the exhaust stayed on the car, I just disconnected it from the o2 housing so weight loss had nothing to do with it..

I ran a [email protected] with the stock exhaust, and the NEXT run I disconnected it and ran a [email protected] (and the next run I ran a best mph of 106.66...bogged the launch and bad 1-2 shift). The car weighted in at 3230lbs with me in it....you do the math there Sammy Science

Here's a scan of the slips since half of you fools won't believe me.

http://home.cogeco.ca/~djeclipse/VinceSlips.html

As you can see I could use some work on my launch...

 

[SPEEDY]

If your car is a non turbo then you will need back pressure. Turbo cars don't need back pressure. Also, that Import Tuner issue is stupid, what they meant to say is a dp, testpipe and exhaust combined made about 30hp. The testipe alone will not make 30hp by itself, more like 10 to 15hp.

 

[Formz]

ok so like 45hp for exhaust, still over 30