exhaust backpressure
- Thread starter GSR
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I measured mine today before cat and it showed 7psi while running 18psi boost, on 10psi boost it showed 5psi. I have a 3in system.
Then i did my bros GT4 celica before cat also and it only had 3psi, running 10psi boost and has 2.5in exhaust.
So dont know if its normal to have this much or not. I'll check again tomorrow after the cat before i end up making up a pipe to replace the cat
to see on a dyno if it will effect performance.
Then i did my bros GT4 celica before cat also and it only had 3psi, running 10psi boost and has 2.5in exhaust.
So dont know if its normal to have this much or not. I'll check again tomorrow after the cat before i end up making up a pipe to replace the cat
to see on a dyno if it will effect performance.
I know and i already do have a hi flow cat. But for testing purposes to determine weather i need to look into a diff cat
with bigger body or not this is the only way to do so rather then just buying and fitting another one to find out that its the same.
with bigger body or not this is the only way to do so rather then just buying and fitting another one to find out that its the same.
After reading this thread i had a read through the book "maximum boost" (my awesome xmas present) to see if he mentions it.
He said to have at least 10 inches of metal tube before the silicone line to disperse the heat.
He doesnt make and claims to what is or isnt acceptable but less i always best. Thats it.
So basicly get some bungs welded in the exhaust at the various points. Get fitting with a nipple to suit. and bung onto a boost gauge you dont car about. Correct?
He said to have at least 10 inches of metal tube before the silicone line to disperse the heat.
He doesnt make and claims to what is or isnt acceptable but less i always best. Thats it.
So basicly get some bungs welded in the exhaust at the various points. Get fitting with a nipple to suit. and bung onto a boost gauge you dont car about. Correct?
thats pretty much it!
Or just weld some steel tube of the appropriate length and take your readings from there.
To seal it, you could tap and place a bolt in it.
I've seen as much as 50kw's gain from on own vr4 by reducing backpressure in the exhaust system.
The hi flow metal cat gave me 30 kw's. The muffler gave me 20 kw's.
Or just weld some steel tube of the appropriate length and take your readings from there.
To seal it, you could tap and place a bolt in it.
I've seen as much as 50kw's gain from on own vr4 by reducing backpressure in the exhaust system.
The hi flow metal cat gave me 30 kw's. The muffler gave me 20 kw's.
bazeng, do you remember how much approx. backpressure did you have at any point of your exhaust?
I measured mine after the cat too and its only 1psi less then what is before the cat and since there is not
much to change after the cat as its just a 3in pipe with a cannon at the back i just decided to leave it alone.
I measured mine after the cat too and its only 1psi less then what is before the cat and since there is not
much to change after the cat as its just a 3in pipe with a cannon at the back i just decided to leave it alone.
I though id have a search on autospeed, they like to mreasure and test everything.
I wanted to see some other readings and was was acceptable.
Also measure it in the same gear for comparisons sake. They say in first the reading will be higher because of the rapid climb of revs pushing more gas through suddenly.
Some measurements of other cars are measured here. The stock 180sx is around 8psi, seems low for a stock car. The vl turbo was 13psi!
But if you upped the boost the 180 sx would change so you have to take it all with a pinch of salt, when comparing to your aftermarket setup.
http://autospeed.com.au/cms/A_108185/article.html
Scroll half way down.
http://autospeed.com.au/cms/A_110210/article.html
Designing exhaust systems. Part 1, 2, and 3 .
http://autospeed.com.au/cms/A_1466/article.html
http://autospeed.com.au/cms/A_1474/article.html
http://autospeed.com.au/cms/A_1484/article.html
I wanted to see some other readings and was was acceptable.
Also measure it in the same gear for comparisons sake. They say in first the reading will be higher because of the rapid climb of revs pushing more gas through suddenly.
Some measurements of other cars are measured here. The stock 180sx is around 8psi, seems low for a stock car. The vl turbo was 13psi!
But if you upped the boost the 180 sx would change so you have to take it all with a pinch of salt, when comparing to your aftermarket setup.
http://autospeed.com.au/cms/A_108185/article.html
Scroll half way down.
http://autospeed.com.au/cms/A_110210/article.html
Designing exhaust systems. Part 1, 2, and 3 .
http://autospeed.com.au/cms/A_1466/article.html
http://autospeed.com.au/cms/A_1474/article.html
http://autospeed.com.au/cms/A_1484/article.html
