Crazy idea for DIY exhaust on the cheap

[sandawgk5]

Ira, I'm not trying to start any crap with you, but back it up if you disagree with me

I cant that is why I disagree. I dont have a lot of knowledge on exhaust theory. I have just always learned that if you change nothing but the size of the exhaust then at low RPMs your torque numbers will suffer. I am not taking it personal, I am a little out of it as I am still on Percocet after my surgery.

Ira

 

[Hogback Fabrication]

Well I did my best to try and explain why that is a misconception.

I have also heard the same thing, but my engineering background tells me otherwise. I have heard others argue the same point as me (dyeager535 for instance) but the general population still believes that smaller exhaust makes better low end power. It doesn't.

Given all of that, there is practically no one on this site that should really be worried about exhaust size. I run Flowtech (the cheapest ) headers into dual 2.5" exhaust. That's the stock size and I don't feel that it really costs me any power.

Leave all the worrying about tuning exhaust to the drag racers. Don't purposely run small pipes to make better low end torque but don't go crazy buying big stuff either.

 

[sandawgk5]

Well I did my best to try and explain why that is a misconception.

I have also heard the same thing, but my engineering background tells me otherwise. I have heard others argue the same point as me (dyeager535 for instance) but the general population still believes that smaller exhaust makes better low end power. It doesn't.

Given all of that, there is practically no one on this site that should really be worried about exhaust size. I run Flowtech (the cheapest ) headers into dual 2.5" exhaust. That's the stock size and I don't feel that it really costs me any power.

Leave all the worrying about tuning exhaust to the drag racers. Don't purposely run small pipes to make better low end torque but don't go crazy buying big stuff either.

Ya basically what I was trying to say I guess. I plan on a single 3" when I get the funds I will go with a set of TES headers and a 2.5" Ypipe. I just need the tax man to give me my money then its awn.

What was the original topic of this thread.

Ira

 

[Hogback Fabrication]

What was the original topic of this thread.

Ira

No joke, sorry fellas

 

[ntsqd]

The spring idea is a good one, not crazy. Essentially you are using it to form a mandrel. Bending thin walled tube w/o kinking it is difficult.

snip.....
I've also heard that if you fill the inside of the tubing with sand you'll get a mandrel bend, (one that doesn't decrease in diameter in the bend area), but you have to figure out how to keep the sand inside of the tube whilst bending it & you have to have a pretty nice bender at the same time.

First rule is to use dry sand. This so that if you need to heat the tubing it won't explode from the steam.
Keeping the sand in isn't all that difficult. Weld a cap on one end of the tube. Fill nearly full of sand. Whittle a tapered wooden block and drive it in, deliberately compressing the sand. Bend at will, but occasionally check that the wooden plug doesn't work loose.

The answer taken from the above link, according to David Vizard (a man of considerable knowledge & experience in tuning engines), to the bigger tube debate:
Without knowledge to the contrary, the biggest fear is that the selected tube diameters could be too small, thereby constricting flow and dropping power. Sure, if they are way under what is needed, lack of flow will cause power to suffer. In practice though it is better, especially for a street-driven machine, to have pipes a little too small rather than a little too big. If the pipes are too large a fair chunk of torque can be lost without actually gaining much in the way of top-end power.

BTW, y'all are in, what my old boss would say, "Violent Agreement!"

 

[SkysTheLimit]

Originally it was about being a cheap a$$ and trying to invent a backyard engineering way to fab up custom exhaust.

I did enjoy the turn it took as I believe all can learn from a "discussion" however lively it may be.

I'll be reading the link posted for further information.

I'm going to just go with the universal kit Ira linked as I do not intend on doing much more exhaust work after this. By the time I figure out a cheap way to bend pipe, I'll have spent more $$ in my time than I would have if I had just ordered pre-bent tube.