i was wondering what types of exhaust people are using on N/A motors running 118 mph or better in 1/4 mile

 

very vague... engine size? rpms turning? these things are necessary. Vipers are running stock exhaust and trap that speed...

 

I run 118 1/4`s and I run thru two three inch mandrel bent pipes over the axle w/flowmasters

 

I have a 383 that used to run 118-119 mph in 1/4 mile in my 1980 z28(dual mandrel bent with x pipe). I put it in my 1984 firebird,same gears same coverter ,ect. but with a single 3 in flowmaster cat back with a mufflex y pipe i can only go 113.5. greezemonkey, i like the set up you have, how is ground clearance?

 

ground clearence Is good!( bout 4 inches guessing) I rarely ever touch anything including speed bumps or driveways..It gets tight over the axle by the fuel tank though...from the side, Granted these pipes are on the outboard side of the frame rails but only because that`s where the hooker super comps dump at

 

..

 

Thanks for the pics and info greezemonkey. I have LT Supercomps too. I think i am going to try and duplicate your system.

 

Ever try, just as an experiment, to run the car with open headers for a few passes? Posts like this always turn into single 3" vs duals and maybe we could get some clear evidence as to how bad single 3" holds back your average high-HP car.

 

I have not run it at the track open, but i have driven it open headers, and there is a huge differance in power. I did just install one of my dynomax bullets in place of the flowmaster.It revs more freely and feels better by the seat of the pants comparsion. I will race it on friday and see how much, if any differance the bullet makes.

 

On my 383, I ran 118 using Hooker Super Comps, dual High Flow 3" cats into a 4" Mufflex.

www.geocities.com/dzperf

 

how loud is that 4" system? the 3" bullet i have on now is way to loud. I'm not goin got keep it on even if it gets me back to 118.

 

It is not too bad with the cats on. I have 2 set ups for my exhaust. One is dual 3" from the collector into dual cats into a
y-pipe right before the rear axle. The other is dual 3" from the collector merging into a y-pipe near the trans tailshaft.

The system without the cats is somewhat loud and does not have a good exhaust not at low rpms. But, at full throttle, it has a sound similar to a Nascar.

www.geocities.com/dzperf

 

I finally made it back to the track. changing only the flowmaster for a straight thru dynomax bullet, I ran a best of 116 tonight. taction was much worse also. Its starting to feel like it did in my z28. I dont think i will be able to get the same power i did with the dual 3 inch ,but its definetly close

 

84firebird383 - Have you tried pulling your front sway bar when running at the track?

 

No. i have done that on other cars, but right now with the 26 spline stock rear end I don't want to hook that hard.I do need to get some frame connectors tho. I also run on street radials as i did on my old z28.

 

My exhaust is similar to greezemonkey's, but it runs under the axle. Works beautifully, only pain in the *** is jacking up the rear of the car is tricky since you need to jack it up by the rearend and not the frame as it will make the rearend rest on the exhaust pipes

 

That looks like a really nice set up Chris. I hadn't thought about going underneath the axel. I still have my dual x set up off of my 80 z28. I might start hacking it up to see if i can get to fit underneath my 84.

 

greezemonkey, do you have a part # for those flowmasters or happen to know how long they are? Im abonding my hooker lts, true dual x pipe setup in favor of slp 1 3/4 and something like ******* exhaust. it sounds ****ing sick on the little 305 with a cam, but ground clearance is killing me with the car lowered on a 25.7 tall tire

 

I trap over 120 with a single 3 inch exhaust, which is only temporary as I will soon have a 3.5 inch catback to match my 3.5 inch y pipe.

 

Scary A 3" doesn't really become restrictive until you are making over 400 at the wheels.

 

they are 40 series, the least expensive ones around 50 each..they are 13 inches long and 9 1/2 wide. I used a offset/center outlet on the passenger side and a center/center on the driver side..diff use a H or X pipe to tone em` down. I had a similar setup with the small blocks but it used a 2 1/2 pipe and muffler and the pipes ran in the trans tunnel never had any issues with ground clearence. Lowered cars and big pipes can be a real pain, the only spot close on mine is where the pipes go over the axle...thinking about getting that BMR relocal kit for the panhard brace.

 

I put true duals on last night using parts I had laying around. Unfortunatley the only mufflers I had are 3" bullets that i had from a previous experiment, man they are just to loud.I just used the S pipes from my mufflex y pipe to go underneath my crossmember and the ran straight back and did a turn out before the axel.I am going to try and run it wednesday the 21st if I get back to 118-119 mph.

 

Cars without tail pipes are louder on the inside than they are on the outside, if you could route it to the side or over the axle it would be more friendly on the inside of the car

 

With the bullets the whole set up is about 2db maybe 3db quiter than open headers. If I keep true duals I will go with quiter mufflers and get some tail pipes, not to metion reroute the pipes into the drive shaft tunnel.Right now I just want to see if it will make it back to at least 118 mph.

 

Run an X pipe to quiet it down. My vortec 350 with bullets and an x pipe almost traps 112 mph and is the quietest amongst my friend's cars.

 

Just 3" duals no H/X pipe into Flowmaster 40 series. Ground clearance better than my old dual exhaust but now loud as helll!!

Should easily be in the 10's uncorked, just wanting to tune for max effort street trim right now.

 

well if your looking for options why not call spintech and order some of thier flat nascar pipe and 3.5 inch thick mufflers.They'd be much quieter than the bullets and offer great ground clearence and still benefit from 3" diameter pipe. Only drawback is this set up can get expensive.

 

Lets see. 406 SBC NA: edelbrock headers, non mandrel bent y connection, edelbrock single 3 inch cat back, 11.84 @ 117.8 mph. Full weight, air cond, roll bar, stock saladshooters, moser 9, it is heavy, etc Opened it up and ran 118.1 mph. I can't make sense of it, but that is what it did. (of course, I check the a/f with a wb sensor and it was the same open/closed) Hooker long tubes are on, waiting for y pipe.....

 

Alright, it's in the 10's with dual 3" and flowmasters at 122mph-nuff said

 

4600 stall and, 3 speed, race gas, etc. and are pushing it on street trim.....do you have a modifications to et list of how you worked the time down?

 

Full interior with stereo system, 4600 TCI 9" stall, 50/50 mix of 92 octane from BP station down the road and 110 octane VP from gas station by the track. What kind of mods to et list are you looking for? The entire drivetrain is new and bugs were worked out, some of the members from the board can vouge first hand at the kind of street car this is, oops I did take out he back seat casue the back of it was was hitting my cage and it looked gaay with just the seat cushions in there, other than that look at my weight and ask yourself, does that really add up to a stripped down race car? Plenty of pics/posts, etc...do some searching under the user name.

 

I havent been able to get back to the track yet. Last Wednesday was cancelled because there was a chance of rain. Right now I still have the duals that turn out in front of the axel. The car feels faster but is much to loud. Assuming i can get back to 118-119 mph I will most likely go with oval exhaust for the permenant set up. I am also considering putting the 3" single bullet set up back on and seeing how fast I can get it to go. The one other differance is on the old camaro I had dash 10 fuel line from the tank to the pump. On this car I still have stock fuel line.

 

if i did the spintech exhaust with nascar mufflers and dual cats would my car pass cali emissions???