stock pipe off turbo was told better than 3inch round?

[Cntyview]

Hey Guys new to forum and always ran my 95 powerstroke stock...I'm just able to do a few upgrades. My mechanic I've used since its been new has always told me that the stock pipe off the turbo is the Equivalent to a 4 inch round pipe and has no restrickion for mild chips/reprogram. We get into it every time this comes up as everyone is replaceing it, He's A GREAT Ford trained powerstroke MECHANIC owns and operates a powerstroke only shop & LOVES THE 7.3. He's has talked me into leaving it (Squish pipe) doing a cat delete & 4' stainless all the way back with a no restrick muffler & a tymar type air system & reprograming the computer & steping up fuel psi......I've lurked forms and never seen this arguement...any input greatly appreciated
thanks Dave

 

[h2odrx]

I'd go with the 4" down pipe what will it hurt?

 

[Cntyview]

It takes a porta power to sueeze a 3 inch round in & if you dont get it right it will rub & rattle. a 4inch round would mangule the firewall possibly break the seal on the tranny tunnel....thats his agrument...the stock squish pipe is the same as a 4in in voluume, but everyone is selling 3inch & installing them?

 

[janos1]

Well first off, Welcome to Oilburners. I was under my truck today and was thinking "Boy I gotta change this thing." IMHO, I would remove the "Squish" pipe. Because the air coming out of the turbo is quite turbulent as it is. Then to try to force it down the only makes the flow that much more turbulent and raises EGT's. Besides if you have already did the 4" stainless out the back then you leave the "squished pipe", to me that would be a waste of the stainless. Just my 2 cents.

Maybe the mechanic is not too thrilled at the prospect of getting the old plumbing out and the new one in, There isn't a lot of room in there in the first place.

 

[94f450sd]

for a 3" pipe all you need to do is slice te pinch weld lip in a few spots and bend it flat.the pipe wont rub or rattle.4" can be done but requires adding a hump to the floor.being a stroke lover this guy should know that a 3" pipe will flow more thAN A PIPE THAT IS SQUISHED down to 1".and if hes gonna argue over it,id find a new mechanic.

 

[Double-S-Diesel]

Volume wise the stock pipe is the same
but the problem is the shape and the severe bend right off of the turbo

 

[Double-S-Diesel]

Volume wise the stock pipe is the same
but the problem is the shape and the severe bend right off of the turbo

 

[rthomas]

The 3" Dp was the only non chip/fuel mod that made any difference, I use a local steep hill for power testing and I gained 4mph from just the DP, as for the rest of the exhaust going to 4" made no difference, the airbox just made it louder. I think its the only mandatory upgrade before adding a chip or tuner.

 

[wils2527]

I agree with rthomas. The Downpipe is by far the first upgrade that these trucks need. It will seriously lower your EGT's due to a smooth flow leaving the truck. The DPF after the downpipe is a whole different can of worms. But I would suggest doing the downpipe and the chip to improve your fuel/power wants. Let the truck breathe!

 

[94f450sd]

downpipe,kill the kitty and 4" it.open air intake and itll be a whole new truck

if your state requires the cat to be on it,gut it and ram a 3" pipe through it and weld it up.

 

[rthomas]

I gutted my cat and now its a mini muffler, tones it down just bit.

 

[Diesel_brad]

for a 3" pipe all you need to do is slice te pinch weld lip in a few spots and bend it flat.the pipe wont rub or rattle.4" can be done but requires adding a hump to the floor.being a stroke lover this guy should know that a 3" pipe will flow more thAN A PIPE THAT IS SQUISHED down to 1".and if hes gonna argue over it,id find a new mechanic.

What he said. FIND A NEW MECHANIC. Yours is obviously

 

[EMD_DRIVER]

Another thing to consider, is that the exhaust coming out of the turbo is spinning from the turbine wheel. If the EBPV is still there, it's abruptly stopped from spinning. If the EBPV is gutted and a 3" DP installed, the exhaust can stop it's spinning on it's own.