Speed Shop making Exhuast?




I have an aftermarket set of chambered pipes, basically what is sold on MAD for C4 92-96. I didn't know MAD had them and found the manufacturer to buy direct. Point is, HERESY ALERT the guy advised me to go smaller than 2.5". I have the aluminized 2.25" inner diameter pipes and they flow very well. I can put my hand more than a foot behind the tips at idle and feel the power pulses strongly. This to me indicates that the velocity is kept up all the way through. Remember, 2.25" inner. If you don't have a big cube stroker you don't need something bigger in a true dual. The larger the pipe the less the velocity of the air.
It cost me $500.00. The same thing thing in T304 stainless is about $900.00. Dyno numbers are pending.
What I think is that for $1100 you should be getting titanium.
[Modified by 94lt1torchred, 11:01 PM 1/24/2003]
[Modified by 94lt1torchred, 11:02 PM 1/24/2003]
The thing is though if I were to go B&B that is 1,200 not including shipping nor installtion... Hmmm, this is very confusing not sure what to do, I mean I already got flowmasters I might just add longtubes, and thats the thing he said that longtubes wouldn't fit my vette since it was 2 low now is that true?..
The Speed shop is Called EIP tuning located in Westminster, MD


The Best of Corvette for Corvette Enthusiasts
The thing is though if I were to go B&B that is 1,200 not including shipping nor installtion... Hmmm, this is very confusing not sure what to do, I mean I already got flowmasters I might just add longtubes, and thats the thing he said that longtubes wouldn't fit my vette since it was 2 low now is that true?..
The Speed shop is Called EIP tuning located in Westminster, MD
I have true dual (separated) pipes with no x-pipe and I have no problems with resonance. I know the x-pipes on the C5 give it a unique sound, but I can't figure out why everyone is crazy about installing them on a C4. Maybe I'm just a nostalgia freak and want to duplicate the sound of muscle in the 60s. The pipes I have do that very well. Frankly I would rather have my car sound like a 66 than a Z06.
But I seem to be alone in what I want from the exhaust sound.
If you don't have a big cube stroker you don't need something bigger in a true dual. The larger the pipe the less the velocity of the air.
[quote]
Bigger exhaust may not help but it sure won't hurt.
Think of it this way:
Use a 1/2 inch exhaust pipe. What will THAT do for velocity?
What will it do for volume?
Is the velocity closer related to piston speed or pipe diameter?
What would you rather have, a 1/2 inch exhaust pipe or a 6 inch exhaust pipe?
Just a few points to ponder.......


Bigger exhaust may not help but it sure won't hurt.
Think of it this way:
Use a 1/2 inch exhaust pipe. What will THAT do for velocity?
What will it do for volume?
Is the velocity closer related to piston speed or pipe diameter?
What would you rather have, a 1/2 inch exhaust pipe or a 6 inch exhaust pipe?
Just a few points to ponder.......
Local shop is going to do mine for $800 installed.
3" Full Mandrel bent tubing, flanged at my headers. Another set of flanges for Cats or bypass pipes (system includes the bypass pipes), then back to the end of the car, with flanges and straight pipes out the back, as well as a set of flowmasters that will bolt to the flange.
So essentially two exhuast systems for $800 installed... $1100 seems steep...
BTW this is from a really good shop, does alot of custom turbo systems in town.
Oh yeah, he said it'd be only a couple more dollars (20-30) to do an X or H pipe
Matt
[Modified by VetteRacer282, 3:24 PM 1/25/2003]
Bigger exhaust may not help but it sure won't hurt.
Think of it this way:
Use a 1/2 inch exhaust pipe. What will THAT do for velocity?
What will it do for volume?
Is the velocity closer related to piston speed or pipe diameter?
What would you rather have, a 1/2 inch exhaust pipe or a 6 inch exhaust pipe?
Just a few points to ponder.......
Total exhaust pipe area . . . . . pipe diameter
18.85" cross section area . . . . 3 in
15.71 . . . " . . . . . . . . . . . . . 2.5 in
14.137 . . . " . . . . . . . . . . . . . 2.25 in
37.699 . . . " . . . . . . . . . . . . . 6 in
Just plain old Pi*D * 2 for the area of two pipes
So you see that a very small increase in pipe diameter is a very large increase in cross section.
Just to throw out a comparison of some (ir)relevance. Back in 92 or 93 (not sure) Dodge went from a single 2.5 in pipe to a 3 in pipe on the Cumins Turbo diesel P'up. They gained 50 HP from 250 to 300 in standard form. They have not increased the pipe diameter since, so the champion torque monster from Detroit even today is running a single 3 inch.
Be a little careful of going too large on a Vette with duals. Please remember, I said I picked up the phone to order 2.5 in pipes, and the manufacturer talked me into down-sizing to 2.25 instead. I'm very happy with what I got.
[Modified by 94lt1torchred, 11:29 PM 1/25/2003]
[Modified by 94lt1torchred, 11:33 PM 1/25/2003]
Congrats on your pi d squared calculations.
That backs up my point 110%.
The comparison between a 1/2 inch and a 6 inch exhuast was for illustration purposes and was meant to get those folks that think ANY back pressure in an exhaust system is a "good" thing to possibly reconsider the thinking.
Well, I take that back. The back pressure caused by a turbocharger may be a good thing. :)
On a NA engine if one could enable a vacumn in the exhaust to scavenge the exhaust gasses out, the AF mixture could be adjusted in a positive way to create more power.
Exhaust augmenters do this very thing.
If an engine NEEDS back pressure then the AF ratio is not set correctly or the
IE Overlap is too large.
For the same money the larger exhaust pipe diameter offers greater performance POTENTIAL than smaller.
As your calcualtions show, the cross sectional area increased substantially when the pipe diameter is increased. Of course there is a point of diminishing returns that is reached when the flow potential reaches the maximum flow the engine may generate at it's designed upper RPM.
18.85" cross section area . . . . 3 in
15.71 . . . " . . . . . . . . . . . . . 2.5 in
14.137 . . . " . . . . . . . . . . . . . 2.25 in
37.699 . . . " . . . . . . . . . . . . . 6 in
Just plain old Pi*D * 2 for the area of two pipes
If you use.....
Pi*D for circumference
...and...
Pi R squared for area
...it works better
;)
18.85" cross section area . . . . 3 in
15.71 . . . " . . . . . . . . . . . . . 2.5 in
14.137 . . . " . . . . . . . . . . . . . 2.25 in
37.699 . . . " . . . . . . . . . . . . . 6 in
Just plain old Pi*D * 2 for the area of two pipes
If you use.....
Pi*D for circumference
...and...
Pi R squared for area
...it works better
;)
OK the areas of 2.25, 2.5, and 3.0 inch pipes. (who cares)
3.0........28.274 for one, 56 for duals
2.5........19.635 for one, 39.270 for duals
2.25.......15.904 for one, 31.8 for duals
It is not linear, and a small increase in diameter is a very large increase in cross-section area (and likely flow characteristics).
It's hell to get old and can't remember high school math. I hope I remember where my car is. And if I find it, I hope I can remember how to drive it.
[/edit]
* 2 was <times 2> for two (2) pipes. We're talking true duals here, not a y-pipe deal that actually restricts to one (1) 2.5 or 3 in pipe somewhere under the car. I was trying to compare total area provided to the engine. And only 4 cylinders are dumping into a pipe, but the x-pipe changes things later downstream.
Just for the record, I have been told that 2.5 " is enough for a 350-355. I was thinking 396 or 406 for a big stroker that can use 3 in. Any BBC is another discussion entirely.
[Modified by 94lt1torchred, 8:53 PM 1/27/2003]
[Modified by 94lt1torchred, 11:24 PM 1/27/2003]








