my 4" downpipe install

ryanss22 · Feb 5, 2013

So on my 96 f-250 I installed an Irate T4 kit in 321ss and am going to be running a s475 for pulling. I decided since I had my cab off for body work I wanted to run a true 4" DP.. I mocked up the DP with 4" stove pipe and am glad I did!! lol It was a bit involved with cutting out the firewall bending and patching it back up to fit without rubbing. I put heat reflective tape on the engine side to help stop heat from getting into the cab, also going to wrap the DP. here are some pics and what it took to do..

ryanss22 · Feb 5, 2013

sorry cant figure out how to post more then 5 pics at a time

ryanss22 · Feb 5, 2013

and the fire wall all patched up and done. you can see how much I had to cut out and bend. Here's my turbo and the flange also.

1ofakind79 · Feb 5, 2013

Looks good. Makes me glad I have a SD though a 4" DP just bolts in.

ryanss22 · Feb 5, 2013

I can give this word of advise if some wantes to try it, eaither add a 2" body lift or like i did run a plank through the cab to a chain fall and unbolt the front body mount bolts. allows you to tilt that cab back enough to work on...

Cr500 · Feb 5, 2013

I used to make a outlet for the stock 3 bolt turbine housing that used a 99 up dp flange so you could bolt on a 99 up 4" dp. It was a nice part, radiused from 3"-3.5". It took massaging but it was never that crazy of a job to get the 4" tube in there. I always at least replaced cab mounts with polyurethane ones to get cab right. But if I mounted a turbo square on engine kinda like yours a 3.5 was usually all I built. There are just things on a 99 up that are taken for granted, room at rear of motor would be one of them!

KBMKVIII · Feb 5, 2013

no hijack but with your experience can it be done cab on cutting the floor from inside easily?

going to do my 4"dp next few weeks when the gt4202r goes on.

also how much massaging did you have to do for the turbo to firewall clearance?

have read some threads but your pics really help.

thanks

ryanss22 · Feb 5, 2013

yes it can be done with cab on from inside... you will have to pull back the carpet and slice the black insulation right by the firewall. it's a lil right of center of cab. best bet would try to get at it from engine side and drill a few tracer holes so ur not completly "blind" your basically cutting out the pinch weld.. make sure to leave at least 1/2 inch all the way around

for the turbo I just had to hit in the firewall right bellow the wiper motor where the race cover hit... other then that lots of room. feel free to ask any ?'s any time..

edit- after looking back at my pic's i dont belive it is possible from just inside the cab.

KBMKVIII · Feb 5, 2013

im thinking mock up the dp and turbo on my spare motor. then take a few bs measurments.
then pulling out the bfh and cut off wheel. also thanks for the good pics.

ryanss22 · Feb 5, 2013

sounds like a good plan man. for my s475 I used 2 90* elbows to get the bends. if youd like any other pics pm me and i can just e-mail or text them to you..

m j · Aug 18, 2013

subin'

what s the p# for the vbandreducer?

Bair · Aug 18, 2013

I put my 4 in" DP in with the cab on. Shoot, it's been 3 yrs ago now an I don't remember the details but I just hacked it out with a sawzall and then semi flattened a piece of 4" exhaust pipe to weld in to cover the hole and give a curve to it. I do have a 2" body lift as well. Makes doin anything engine wise on an obs a lot easier.

ryanss22 · Aug 20, 2013

sorry not sure on part #. I ordered one from James at barder turbo when he rebuilt my turbo. He's a dealer on here and will be more then willing to hook you up.

Old OutLaw · Aug 25, 2013

it was a PITAzz, but we did it from inside the cab, without tilting it...

you have to cut out the floor as high as you can go, and lose the dash brace, but it's possible....

would I do it again? nope.....

it does cool a bit better, and spools a bit better down low, othern that, no difference....