View Full Version : Bolt ons exhaust setup


PowerTalk
11-08-2009, 03:49 PM
I'm after some feedback for a drag setup so if the mods could keep it in this section please :)

I want to chase the bolt ons record and I'm having trouble deciding on the exhaust.
I'll be running 1 7/8" longtubes.
Would I be better off running 3" pipe off the headers then into a custom twin 3" into 3.5" merge, and then single 3.5" pipe out the back with one 3.5" resonator?

Or would I be better running twin 3" true duals with twin mufflers and a resonator?

Or would I go fastest with 3" cutouts after the headers and not worry about the back end?

Any help would be appreciated.

JL ws-6
11-08-2009, 04:11 PM
Tune the car in open loop so the o2's don't do anything, and I wouldn't run a thing past the headers.

Save the weight you'll need every bit off the car you can get.

PowerTalk
11-08-2009, 04:23 PM
The car will be SD tuned open loop.

I was originally going to go that way, I have just been thinking that if it's going to reduce my torque in the low end (which I won't have much anyway!) then it will adversely affect my 60ft and undo any weight advantage I'd make?!

CamaroRacing12
11-08-2009, 05:32 PM
open headers.

Magnet
11-08-2009, 05:52 PM
Your not going to lose much low end, go open headers or a 18in pipe right off the collector if your actually going for the record.

PowerTalk
11-08-2009, 06:18 PM
Thanks magnet, that's exactly the kind of info im chasing!!!

JL ws-6
11-08-2009, 08:39 PM
Save the 18 inches of pipe and don't waste your time. I played this game already, started with 24 inches, cut it to 20, 18, 16, 12, 8, took it off, made absolutely no difference at all.

Open loop SD and leave the headers open, a turndown if you must. You're going to be at an rpm for what 5 feet of the track that might matter? Even then, I doubt it.

when I played this game I did it with a set of 1 3/4 headers with 3 inch collectors on a 402, and going from 24 inches to nothing was not even noticable. No gain at all having the pipe there. If you had the o2's in the headers doing something then yes it would be needed, but if not save your $.

PowerTalk
11-08-2009, 09:46 PM
Save the 18 inches of pipe and don't waste your time. I played this game already, started with 24 inches, cut it to 20, 18, 16, 12, 8, took it off, made absolutely no difference at all.

Open loop SD and leave the headers open, a turndown if you must. You're going to be at an rpm for what 5 feet of the track that might matter? Even then, I doubt it.

when I played this game I did it with a set of 1 3/4 headers with 3 inch collectors on a 402, and going from 24 inches to nothing was not even noticable. No gain at all having the pipe there. If you had the o2's in the headers doing something then yes it would be needed, but if not save your $.

Thanks very much!!!!
I appreciate it :hail:

Magnet
11-08-2009, 09:49 PM
Save the 18 inches of pipe and don't waste your time. I played this game already, started with 24 inches, cut it to 20, 18, 16, 12, 8, took it off, made absolutely no difference at all.

Open loop SD and leave the headers open, a turndown if you must. You're going to be at an rpm for what 5 feet of the track that might matter? Even then, I doubt it.

when I played this game I did it with a set of 1 3/4 headers with 3 inch collectors on a 402, and going from 24 inches to nothing was not even noticable. No gain at all having the pipe there. If you had the o2's in the headers doing something then yes it would be needed, but if not save your $.

I haven't played that game myself, but I will take your word for it, I was just offering an alternative, the overall point that we both agree on is that he should run as little as possible, and if he runs 02's he will need the extensions :cool:

studderin
11-08-2009, 10:25 PM
I ran tubes, with a slight turndown I made up when I took everything off for weight. 16" inside 18" outisde form the MCSA of the merg in my collectors. worked good, same maff tune Ive ran all summer with the fast92.


I asked about this same thing, and someone that did some dyno testing of lenghts, posted in good info about a gains he found.
http://www.hardcorels1.com/vbulletin/showthread.php?t=3943

Magnet
11-08-2009, 10:51 PM
I ran tubes, with a slight turndown I made up when I took everything off for weight. 16" inside 18" outisde form the MCSA of the merg in my collectors. worked good, same maff tune Ive ran all summer with the fast92.


I asked about this same thing, and someone that did some dyno testing of lenghts, posted in good info about a gains he found.
http://www.hardcorels1.com/vbulletin/showthread.php?t=3943

interesting info..

JL ws-6
11-09-2009, 04:16 AM
I don't know about any of that... I tried it where it matters ON THE TRACK. Ther results were.. no difference at all.

I'd save yourself the time. Like I said... the place where the car is all the time (over 5000 rpm) is all that matters, you're at an rpm less then 5000 for probably about 5 feet of the track, so tuning/adjusting for that isn't going to get you anywhere.

If you have the ability/access to play with collectors, primary lenth/diameter then yes I am sure you can build something that will work better then what is available to the regular guy, but I am not sure what kind of $, time and resources you have.

BlackScreaminMachine
11-09-2009, 06:30 AM
^ Listen to JL. He does know what he is talkin about. IMO like his for this record, extreme weight loss savings is a key ingredient.

GL

promod1955
11-09-2009, 09:14 PM
If you want an exhaust system, this is the best thing to run. 304 stainless x piped 3". Fabbed stainless muffler. The whole deal only weighs 10lbs. Chromoly light weight trans mount and driveshaft loop.

It's for sale too!:devil:

A bolt on car sounds like crap with open headers in my opinion. It makes it sound like a boat.

http://i51.photobucket.com/albums/f361/promod1955/pics078.jpg

promod1955
11-09-2009, 09:32 PM
what i didn't add was this was on the bolt on car in my sig with the mph record

JL ws-6
11-10-2009, 05:46 AM
I'm more interested in the rear shock mounting/position, any more pictures of that?

promod1955
11-10-2009, 09:03 AM
It's real basic. Just a typical cross bar up top and those adjustable bottom deals everyone sells. The car doesn't have the stock gas tank in it of course. I did the top nice so later down the road (right now as a matter of fact) when it got a 9" I wouldn't have to redo it. Well now its getting a 28" tire and im lowering the car another 2" so now I have to cut all that out and move the upper mount higher up to get my shock center to center the same. so much for that.

Don't use those bottom mounts on anything heavy with A LOT of HP. the cad plated plates rip where the shock bolt is. If you put a doubler plate at the shock bolt hole I'm sure it would help that.

http://i51.photobucket.com/albums/f361/promod1955/pics079.jpg

JL ws-6
11-10-2009, 03:23 PM
I was interested how you did the PHB with them, that's pretty neat. I don't know if that would fly for stock suspension, but I don't see why not.

If I do that, I'd get the solid alum machined shock mounts, the cad. ones are nice, light and cheap, but I've heard of them breaking like you said.

Nice setup, too bad you're not a fab guy for hire and were closer to CT, I'd have some work for ya :)

promod1955
11-10-2009, 04:04 PM
Thanks trigger on here bought that suspension and I'm making some pretty trick suspension for it now. That's legal for stock suspension. That's pretty tame compared to the new drag radial cars being built.

This is what I do for a living actualy. I do work for out of state people all the time.