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Author Topic:   Exhuast
19J
Dirt Freak

Total posts: 370
posted May 08, 2005 01:48 PM  
What is everyones opinion on exhaust. Our track said you must run 1 1/2" then they thought wow the cars got faster not slower. So they changed the rule back to open. Knowing this what would you run and why? I just mean as pipe size and muffler with or without no cat. Stock manifold. No o2 sensor. Thanks. I dont know if i should keep it or change it.

Dunnracing98
Dirt Full Roller

Total posts: 63
posted May 08, 2005 02:00 PM  
me and few others here in colorado run headers out of esslinger pricy but worth it a few run muff but i dont and exhaust stops right past fire wall might be something to check in too

racerman707
Dirt Freak

Total posts: 374
posted May 08, 2005 02:21 PM  
If it made you faster keep it.

rnoswal53
Dirt Maniac

Total posts: 120
posted May 08, 2005 02:34 PM  
I ran a Toyota for several years and the header was always better than the stock manifold. Most of the Ford guys ran a stepped header but I think many of them ran too large of diameter tubes. All that I was able to get was a 1 5/8 in primary with a normal collector. Then the same system was offered with a merge collector. I could hear and feel the difference. The collector narrowed to 2 1/2 in. but was a smooth transition and then expanded slightly.

If you could ever see under a NASCAR engine and look at their pipes, they have the same setup. Mainly you want the pipes to come out straight off the head for a short distance then start curving. There is also a science about the length of the primary tubes that a stock manifold just can't match. There is a reason behind a cast iron manifold on a stock car, but it doesn't work well on the track.

Bigger is not always better. Just rambling, but go with what is making you faster, but don't always copy your competitors.

Russ

Festy46
Dirt Full Roller

Total posts: 59
posted May 08, 2005 02:39 PM  
For myself, I run a pipe that is equal to the hole size in the end of the exhaust manifold. I have heard some guys say that a little smaller pipe creates more velocity and thus better flow. Another guy told me that the length was important. He said you should spray paint the exhaust pipe and then run the car hard. Wherever the paint stopped burning off the pipe was where you wanted to cut it off. I thought about trying this, just never got around to doing it.

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Gas right. Brake left. No bumping.

19J
Dirt Freak

Total posts: 370
posted May 08, 2005 05:15 PM  
I cant run a header must be stock manifold. I cant say it made me faster. I mean ive been going at this a couple of years and im getting faster learning the car better. At the end of 2 yrs ago i was top 10 about 7th usually but ive had a lil miss it was rust in my tank so we switched that. Rebuilt the carb never got to run it. Then last year went to 1 1/2" exhuast and first 2 nights out had top 5's the car has been fast so i really cant say either way. I guess i dont know if it is for the better or worse. I mean the car setup is getting better and better now its about perfect for me. Exhuast must run past drivers seat. Not supposed to exit side of vehicle due to someone getting burnt from a car that threw flames while they was by it. Thats why i was curious to see what everyone did. Im thinking about going back to the "stock" pipe. Its like 2 1/4" that way the motor can breathe but yet still has back pressure.

Zypher
Dirt Roller

Total posts: 22
posted May 08, 2005 07:10 PM  
First you said your rules allowed for 1 1/2 pipe... then you said you had to run a manifold.. the 1 1/2 is a header and if your rules say open like you also said above one time then go get a tri y header.

19J
Dirt Freak

Total posts: 370
posted May 09, 2005 10:21 AM  
Ive ALWAYS had to run a manifold. When it comes out of the manifold it has to go down to 1 1/2" size pipe. When i say open. I mean any size pipe. But you must use stock manifold. Sorry for the confusion.

bigphillb
Dirt Roller

Total posts: 19
posted May 09, 2005 11:55 AM  
What motor? There is a long write-up on 4m about this subject. Also ask the people that are winning what they did.

19J
Dirt Freak

Total posts: 370
posted May 09, 2005 12:08 PM  
They build big motors. In our class if you wanna win you cheat. Its very sad to say but it is true. I have not seen completely stock car win with everyone there. Ive seen them win with 2 features and not the fastest car in their feature. Our rules say stock. Its a 2.6 mits. Im just trying to figure out what would help me the most since i dont have a "cheater" motor.

Dunnracing98
Dirt Full Roller

Total posts: 63
posted May 09, 2005 05:06 PM  
well we have that problem too and i run a souped up motor but like us we get to racing hard and tear each other up eventually and then you will come thru for a win. just enjoy the racing and if they want to cheat they will pay when they get caught. Until then just sit back watch others lines and just tell your self your going to stay right on that guys tail no matter what i had to do that for two years befor i started to figure out what i could do to keep up i now am sitting out to a blown engine because i tried a trick to cheat that a lot of people are afraid to try and snapped the crank

bigcityracer
Dirt Freak

Total posts: 431
posted May 09, 2005 06:51 PM  
I have very good power from mine. 2.4 toyota.
Run stock pipe from manifold about foot passed your feet under can, then bump up 1/4 inch to muffler then another 1/4 to pipe after muffler about 2 foot peice after that.

quote:
Originally posted by 19J:
Ive ALWAYS had to run a manifold. When it comes out of the manifold it has to go down to 1 1/2" size pipe. When i say open. I mean any size pipe. But you must use stock manifold. Sorry for the confusion.


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