pred

My exhaust is in fine condition, and i am looking at the bigexhaust.com 4" system, My question is??? Can i buy the parts to keep my stock 3" down pipe, and mate the 4" system to it without fabbing anything? The BE system has a 3" down pipe, and when i called, noone knew if their exhaust would mate to my stock 3" down pipe, I see no reason to buy a new down pipe is it is the same as what i would be taking off! Also, they are saying that the system is for an IC ttruck and it is the same as my non IC truck, Is the only differance the heat shield?
Mine 1989 D350 rwd 5 sp srw
Thanks,,
Peter.

gman07

I'm sure bgilbert will chime in as soon as he sees "bigexhaust.com" in the title. I don't see any reason for you to buy their downpipe. If they have a 3" downpipe with the kit I would think they would adapt it up to 4" at the extension pipe, so I think you wouldn't have any trouble mating it to your stock downpipe. I don't have experience with it though (yet).

JD730

I have a truck with a PO installed 4" system, probably "bigexhaust.com" but I'm not sure. It has a new 3" down pipe with a machined flange instead of the orginal formed one that cracks, which is what this one did. The extension pipe is necked down to 3" right where the down pipe stops. And yes I think the only difference in the downpipe is the heat shield from IC to non-IC trucks.

flashgordon

The diff between the non and intercooled ex is that the intercooled ex has a heat sheild on the elbo of the down pipe!

if your not going with a 4 down pipe the i would us you old down pipe allso!

DLittle

I put a big exhaust on a couple of months ago but I use a 4in downpipe. I saved the piece I cut off the big exhaust system where it goes from 3in to 4in and I checked it on my Factory downpipe and it looks like it should go inside there system. It just depends on where you cut your old DP. I think that if it didn't fit a flat exhaust band clamp whould hold them together.

pred

So from what i read here, i will need to cut a bit off of the stock down pipe?!!, then just slip the new piece on? The kit from big exhaust comes with a 3" down pipe, and the first piece after is a 3/4 adapter, I just dont know if they will only butt up, and not slip in.
Peter.

clinton81

Hey, I just bought a 1st gen and found a place in Wa. that sells a 4" turbo back for the same price i could find any other kits it is called stans headers in enumclaw, wa

PapeCAT

well my '89 3" dp factory tailpipe was not welded together, it hda the slot and tab setup and I just pulled it apart by hand, I'm sure you could just slide the big exaust piece in there, the one that goes from 3"-4" no cutting needed and yes you can use your original dp. mine cracked though so I actually ended up buying the dp long before the rest of the setup

Alec

I just put a bigexhaust .com system on my truck, using the stock 3" downpipe. It all matched up just fine: you do not need to buy the downpipe from them.