3" vs 2.5" header & exhaust

[RTTTTed]

#1 - I wouldn't use a 1 7/8" header except on a Forced Induction or a race engine. For FI I'd use 1 3/4" and for normally aspirated engines (stock) I'd go with 1 5/8" headers. Anitreversion or stepped headers up to about 550rwhp (unless usign GG or Stryker heads). Large tube headers without massive exhaust flows (like Forced Induction) lose velocity if the tubing is too large. The stepped headers enhance exhaust flows because as the exhaust gases cool the tubes work better with larger tubing the farther away form the engine (heat source), similar idea to the antireversion.

2. The Corsa is Stainless Steel and that means that it's brittle and misalignment or too much movement will crack the pipe, normally at the welds (stress points).

3. The Corsa in the pics has an H or equalizer pipe before the rear canisters. Changing the H pipe to an X would require removal of the rear muffler segments and increase the noise while changing to an X pipe would work the same as the Equalizer pipe. I would expect the exhaust to get much louder.

I'm guessing (from my exhaust experience) and have not done what you are thinking of. I did have Random Tech exhaust with Hiflows and it used an X pipe at the rear. Idled louder than my ACR's Hiflows with Corsa Street exhaust. WOT the Corsa sounds nice and not too loud (stock headers). Random tech was quiet at WOT compared to the Corsa. My No cats, 1 3/4" TNT headers and Corsa track exhaust GTS is extremely loud, but always gets me compliments.

[media]http://www.youtube.com/watch?v=XbOnT9Qj3ew[/media]

has my 3 Vipers and their exhaust systems that can be heard. Search rtttted on youtube.com and the individual vids can be seen.

Ted

 

[EFI-1]

Your 01 Sapphire rocks Ted.....SICK!

 

[Chuck 98 RT/10]

All 4 stroke engines work better (at all speeds and rpms) with headers and no exhaust, even a lawnmower. Mileage, torque and hp are all increased with headers and no exhaust.

Dunno if I can agree with you about the mileage comment Ted. I know we all used to try to convince our parents of that when we were kids but in reality more performance = more fuel flow = worse mileage, in my experience. Dunno. Someday maybe I'll put headers on the RT/10 and do some documentation. Could be fun.

 

[RTTTTed]

Dunno if I can agree with you about the mileage comment Ted. I know we all used to try to convince our parents of that when we were kids but in reality more performance = more fuel flow = worse mileage, in my experience. Dunno. Someday maybe I'll put headers on the RT/10 and do some documentation. Could be fun.

The reason that modern cars have tube headers from the factory is because of the emmissions and better fuel mileage, not just the hp.

We usually got 4 mpg better mileage going from stock manifolds and quiet mufflers to free flowing (non restrictive) exhaust. Kind of like using a 1" pipe for exhaust on anything engine bigger than 750cc. 340s came with 2.5" exhaust and free flow mufflers, 440s came with the same. 318s came with 2" single quiet exhuast. Bigger engines have more exhaust and require larger pipe to maintain efficiency. Free flowing mufflers merely have less chocking effect on the engine allowing it to work more efficiently. Similar to the intake side of the engine, less restriction means less few for the same distance and more hp produced for same amount of gasoline burned.

Higher compression increases hp and mileage also. Camshaft aggressive profiles and higher lifts do create more horsepower by keeping the valves opening farther and longer to allow MORE Gas into the engine which obviously will use more gas.

Performance means better stopping, less emissions, better areodynamics, more hp and better mileage.

 

[RTTTTed]

Your 01 Sapphire rocks Ted.....SICK!

It's the exhaust that gets you excited?

Thanks

 

[Makara]

I know this thread is old but the info was never supplied so ...

All 4 stroke engines work better (at all speeds and rpms) with headers and no exhaust, even a lawnmower. Mileage, torque and hp are all increased with headers and no exhaust.

I've noticed a decrease in performance in a few cars with the exhaust disconnected at the headers.

 

[RTTTTed]

I've noticed a decrease in performance in a few cars with the exhaust disconnected at the headers.

Yes, you're correct. Especially with cheap headers. The collector size and most improtant the collector length does make a difference. Usually you need a dyno or drag strip to notice the small difference though. ****** Headers did massive amounts of research. If you instal an equalizer tube between the collectors (even open headers there was also a performance gain of about 5hp). Since Vipers aren't convenient for H pipes and the ones that were used didn't make enough difference to justify the trouble and expense the equalizer pipes seem to only be popular in the rear of Gen 2 cars.

I think that the ideal collector length for most cars was 18" with 12" being suggested for quality headers. Collector length is not as important when an exhaust system is used as the exhaust itself extends the collector.

Although I "heard" of a couple cars that were supposed to be equal with nor without exhaust, all the cars I saw at the track went .2 to .8 seconds faster with the exhaust removed. Corsa and several other 'engineered' exhaust systems are much better than any of the older style mufflers including cherry bombs and glasspacks.

Ted

Ted

 

[Dietz]

Them are some good points, but in the end I want to do up my car so i figured start with the exhaust and go from there. Id love to install a twin turbo on the car, but know the expense is really high and my car is a daily driver. I drive my car every day that I can when I get back from a job. Hell when I did my exhaust Im only a welder at the end of the day, not a mechanic! So there is only so much I can do without paying someone else to do it for me

 

[Black Moon]

Not meaning to hijack but does anyone know of any used Corsa, B&B, Borla or Mopar race. My budget is small due to lack of work and hoping someone got bored and changed systems. I don't like my pipes sound and don't know the brand. They are unfinished with unfinished tips and no markings on them. Are these stock maybe? Any input would be appreciated.
Sal

 

[RTTTTed]

Have you called JonB yet? Checked the classifieds here on the forum?

If those don't work out then you could start phoning all the tuners and ask them. They are often too busy to post here.

Ted