Kylel

iTrader: (2)

I am building a fox mustang with an sbe L33/S475/powerglide combo. Turbo is cast wheel, 1.10 92mm turbine. Car will be a track car that I can drive to work on nice days too. I am doing a 5" downpipe that will exit in front of the front driver's side tire. I am planning on welding a V-band on the outlet with a cap that I can close off for street driving, and open up at the track.

For the street, I want to run the exhaust out the back of the car. I am wondering if I were to do just a single 3" exhaust, would I be hurting anything? It would be a 3" pipe off the 5" downpipe, back to a 3" magnaflow muffler, and a 3" tailpipe. I know it isn't best for power, but when i'm ready for that at the track i'll pull the cap off the 5" pipe. Is there any reason I shouldn't use a single 3"?

SchuttsR1

iTrader: (1)

3" would be fine to run depending on your power level. 5" exhaust on a gasser is very large. 4" would be plenty good if you can fit it with a straight threw muffler should be good for the street.

69-chvl

iTrader: (11)

I'm running a s475 with a 3.5" DP which then splits into a dual 2.5" exhaust out the rear bumper. Going to be tough to get a 3" system in there. It was for me but my rear axle has triangulation braces welded on which takes up precious space. 2.5" was even tough to fit. But we got it in there and its quiet. Someday I'll run the open DP to see what effect the dual exh has on power.

Forcefed86

iTrader: (4)

I'd run an electric cutout and some tiny 2.5" crush bent stuff to the back with a Cadillac muffler.

Bad Apache

I have dual 3" on my Fox chassis (Zephyr). TIGHT fit, made by hand with mandrel bends, but it can be done. Single 3" should be half the work, hahaha!

SPRAYED 01

iTrader: (22)

I run a boost activated cutout for the best of both worlds. I have a 3inch pipe coming out of the side of the 4inch dp thats dumped open to the ground with the cutout at the end.

When Im cruising around the cutout is closed so the exhaust goes out the side of the dp into the 3 inch pipe. When I get into boost the cutout automatically opens and the exhaust takes the path of least resistance which is right out the 4 inch dp.

Sound performance makes the boost activated cutouts. They are expensive thought, around $500. Maybe someone has made somthing cheaper since I bought it.

RoidedSS

any thoughts on dumping the 3" after the muffler, but before the rear axle? Sorry if i missed your plans, i read/skimmed as quickly as I could while at work

JJMclure

Sprayed01 do you have any pics of your setup? Sounds a blast!

ScreamingL

You can fit 4" under the chassis as long not lowered

I personally would not go 3" id go dual 3" from the 5" downpipe

SPRAYED 01

iTrader: (22)

SPRAYED 01

iTrader: (22)

You need to hook it up to boost pressure or exhaust pressure. I ended up hooking it up to exhaust pressure before the turbo. Since back pressure is higher than boost pressure it opens up very quickly when I need it.

You could totally just hook it up to boost pressure just make sure its a dedicated boost reference. When I first bought it I chased my tail because I had it hooked up to a line that also went to the my boost controller solenoid. That solenoid would bleed air off so it wouldn't allow it to open.

Busa_rob

iTrader: (1)

I have a similar set up. 4in straight out the passenger side fender. Also have a 4in fuel exhaust that dumps before the axle. The car is so quiet with the dump open that I'm considering taking the whole exhaust off and setting it on the shelf, and building another 4" dumped exhaust in aluminum just to save weight.

To be honest I think it's louder inside the car with the dump closed.

Here's some videos:

Dump open, both windows down.

Dump open, ps window up, driver partially down.

Dump closed, both windows open.

408GT

iTrader: (2)

I have a full 4" exhaust on my LTD that exits in factory location, with a Magnaflow muffler. It's nice and quiet driving and Stock48 has been bottom 8's with similar exhaust setup. I do wish I could do aluminum once it gets under the car so I could cut out some weight.

Clean94Z

iTrader: (5)

I have a 5.3 th400 s475 in my fox. My first exhaust setup was 5" off the turbo split into dual 3" that went back to the rear end and dumped. Had 18" long bullets. Sounded like your typical dumped mustang.

I run a Boost leash C02 boost controller. On 10psi c02 I would see 11psi,on 15psi of c02 I would see 14psi and 20psi of c02 I would see 18psi.

I changed to a single 5" that exits infront of the passenger tire (turbo mounted on driver side). Sounds like a pickup truck now. Was it restrictive???

Now 10psi of c02 is 14.5psi,14psi of c02 is 17psi and 15psi of c02 got me 19psi

I have some friends that run in different classes. When they run in the street class they run full exhaust. They said typically they would have to turn it up 3psi to run the same thing they did without.

Just my experience!