NT Exhaust help

[badabing33a]

Ok so i cut off my exhaust planning on hollowing out the cat. I couldnt unbolt it since it was so rusted so i had to bring out the saw is all. i cut it and got it off. i grinded the bolts off on the one end and took a pipe and stabbed the inside of the cat. But its hard to get everything out. is there a special way to do it? Or would it be easier to make a test pipe? But oh my goodness, the car sounds so fricken nice with everything off. Its as loud as my IMCA Modified . Its weird because when i shift or let off the gas, the car sounds like a turbo. The little part of the exhaust left after the downpipe makes a loud whistling noise.

 

[BoostedCreation]

honestly it isnt a real good idea running like that! first off the fumes getting to the car is a bad deal but aside front that. a N/T car need some sort of back presure, otherwise you will loose power. dont make a test pipe. sadly enough you can get a bolt on test pipe on ebay for really cheap same as getting a catback and downpie as well. I just got a full setup for my 99 eclipse including a header for 200.00

 

[badabing33a]

Where did you get your setup and headers? And i dont plan on running around with a loud, obnoxious car for long. Dont need a ticket right now.

 

[badabing33a]

I just hollowed out the cat. So tomarrow ill put the exhaust back on. Is it still gunna be loud?

 

[Locke]

honestly it isnt a real good idea running like that! first off the fumes getting to the car is a bad deal but aside front that. a N/T car need some sort of back presure, otherwise you will loose power. dont make a test pipe. sadly enough you can get a bolt on test pipe on ebay for really cheap same as getting a catback and downpie as well. I just got a full setup for my 99 eclipse including a header for 200.00

http://www.dsmtuners.com/forums/fre...8578-exhaust-straight-scoop-backpressure.html

 

[SnprSlick]

http://www.dsmtuners.com/forums/fre...8578-exhaust-straight-scoop-backpressure.html

Beat me to it.

 

[Lofty]

Not sure I believe this.

I remember dumping after the DP on my NT, then getting a full system and the car wouldn't stall out anymore.
So..
I still prefer backpressure, but that's my opinion.
Until I see two dyno slips from an NT, one without exhaust, and one with exhaust, I am not buying it.

 

[RSdriver98]

I took my CAT off and put on a full Megan Racing exhaust with a test pipe and I seem to have more hp. It may just be in my head but it's the way it seems.

 

[Lofty]

That's a bit different then dumping at the DP.

Turbo'd cars can do this because the turbo creates backpressure.

I don't have a cat either, and it runs great, but try taking everything off but the DP.

That article said the less the better right?

 

[Locke]

The less backpressure, the greater the potential for flow, and thus power. With larger exhaust (or no exhaust) you will shift (or lose completely) the scavenging effect. This will be felt as a loss of low end torque.

Top-fuel drag cars use zoomies - minimal back-pressure.

 

[Lofty]

The less backpressure, the greater the potential for flow, and thus power. With larger exhaust (or no exhaust) you will shift (or lose completely) the scavenging effect. This will be felt as a loss of low end torque.

Top-fuel drag cars use zoomies - minimal back-pressure.

Yeah but theres no cut off point in telling where that fine line between minimal, and none lies.

I'll stick with my restricted airflow, less to mess with.

 

[BoostedCreation]

ok my question is this... how can you compare dragsters pushing over 6500 hp to a n/a car that if even bult to the gills, can maybe iflucky achieve 650hp give or take???? and also he referred to drafting from exhaust??/ thats funny cause tecniclly the exhaust has nothing to do with drafting what so ever! its wind resistance. the wind smacking the fornt of the car is double the preasure of the speed the car is moving. thus in turns drafting behind another car as they do helps to eliminate the wind resistance thus putting less strain on the motor allowing the motor to use the power elsewhere. another way to prove my theory is true , when your ride behind a semi on the highwayif you are far enough behind him, you will feel the draft from his trailer. You will also feel the car having to work harder due to the wind restriction. now get in close ad you will see that now the trailer is taking most of the resitance thus taking the strain off the vehicle, and you will also see that you dont burn as much fuel. Now back on the subject of the n/a cars. it has been proven that you can and will loose low end torque if you dont have some sort of backpreasure due to no restriction. Again eliminating the point of doing it. n/a car doesnt have anything to help it off the line like a boosted app, that is why a boosted app can run bigger piping without any issues. The best idea I would recomend for a n/a is no more then 2.5 piping. not too big that you loose the back preasure but does open the exhaust and provides less restriction thus adding more power.

Another thing I have seen alot is runing test pipes or high flow cats. This is fine due to the fact that there is still some kind of restriction at the end of the system. Getting rid of the factory crap and upgrading to new is better. You will see more hp gains and better fuel milage. It has been proven over and over again. No you wont see massive gains but a full exhaust from the header back you might see 10-20 hp give or take dependiing on the quality of the exhaust, and the motor.

 

[Locke]

I can compare 6500+hp dragsters to 650hp street cars because they both use 4 stroke engines, and both employ exhaust systems. Physics doesn't change because one engine is more powerful than the other; and yes, you stated about the same thing the poster of the back-pressure article did concerning drafting.

You also fail to see the point of the article - back-pressure does not equal scavenging. Back-pressure is an unwanted but unavoidable side-effect of an exhaust system designed to provide low rpm cylinder scavenging. The size, length, and size of bends in the exhaust system are the primary factors that contribute to cylinder scavenging. Restriction also is not the same thing as back-pressure. Restriction (such as a muffler or catalytic converter) will actually hurt the scavenging effect, as it reduces exhaust gas velocity.



The back-pressure myth was shot down dozens of years ago. I don't understand why some people want to cling to it so forcefully. With some educated thought, it is pretty clear how it is a myth.

 

[Trav83]

Get yourself a high flow cat. converter off ebay, they're cheap and they work great, just make sure the diameter matches your exhaust.