I'm getting ready to order the mandrel bends for the downpipe I'm going to make. I first thought the 4 bolts flange on my garrett was a 3" but the inner diameter of the Exhuast discharge is less that 2.5".

So my concern is what size downpipe I should go with and what size flange? I wanted to do 3" piping and a 3" 4 bolt flange but it seems as if the flange size for this turbo needs to be the 2.5"??

 

start at the same size as the turbo, then just step it up to 3" as quick as you can.

 

will the 3" flange fit (bolt to bolt)? If so I will just start with a 3" flange and 3" piping

 

No. the 3" 4 bolt weld flange actually is 3.5" (bolt to bolt). You will need to take a 2.5" flange (same as the turbo) and use a conical opening to 3" in diameter. Only if the outer portions of a 3" pipe were dimpled to allow the bolts, could you use a straight 3" pipe from the start.

 

this

to this

to your 3" bends

 

Or you could put the 3" straight up to the 2.5" falnge, and tack around the bolt holes. Then take a flat head screw driver and place inbetween the tacks. and smack it with a hammer. this will indent the tube enough to clearance for bolts.

It is the easiest way to do it. trust me.

 

easiest and most cost effective! I think thats the way I'm going to do it... I didnt realize the discharge was that small!!!

 

Done.. and Done...

 

Thanks guys for the innovative thoughts...