turbo exhaust questions

[Mikey von]

What is the ideal size for exhaust on a built 6.2l turbo. It will have a banks turbo for now. I plan on having the exhaust done at a local shop.I am thinking of going straight pipe.


I need;

crossover size?

down-pipe size?

and down-pipe back size (I was thinking 3.5")?

[93GMCSierra]

3.5 is factory on a 6.5 and I believe its too small, for a turboed, built 6.2 4" might be better.

the crossover I think is 2.5 and the down pipe, either 3 or 3.5 I dont remember.

[Mikey von]

3.5 is factory on a 6.5 and I believe its too small, for a turboed, built 6.2 4" might be better.

the crossover I think is 2.5 and the down pipe, either 3 or 3.5 I dont remember.

good to know. Is there a big jump in price going to a 4" over a 3.5"?

[DmaxMaverick]

There's a huge difference between 3.5" and 4". About a 30% increase in cross sectional areal. The Duramax trucks are OEM with 3.5". The OEM 6.5L is about 2-7/8", IIRC (less than 3"). For a built 6.2 or 6.5, a 3.5" system is an upgrade, and probably sufficient for most applications. If you want to go crazy with the airflow, 4" would be better.

[Mikey von]

My wife tells me I am crazy all the time, but in this case I am just after a solid running truck. It sounds like 3.5" will do me just fine.

[Robyn]

With the Banks turbo I would stick with the Banks XOver pipe.

The 3-1/2 Banks system is what is on my DaHooooley and it flows fine.

A low restriction Banks muffler is great, the sound is nice but not anoying.

The 4" is overkill on a 6.2/6.5 as these engine simply can't take advantage of the flow that the 4 inch can support.

A good clean full 3-1/2" will allow all the air that your gonna push

The stock late model 6.5td's as Maverick mentioned have a 2-7/8 or close plus the Cat/soot trap (Ugly cork) and a restrictive muffler.

The urge to go 4" and look way cool is tempting I know but the return on the $$$$ is probably not even worth a passing glance.

Personally I would at least use a low restriction muffler like the Banks one.

Straight pipes on these things sound Nasty and get anoying on a trip.

Stacks with an echo chamber box in the bed that has a couple baffles in it are not too bad but overall the best choice me thinks is a Muffler.


Have fun and keep us posted


Robyn

[93GMCSierra]

I thought these came factory with 3.5, Oh well learn something new every day.

[thirdstreettito]

I would do 3.5" downpipe/crossover meeting at a 4" back to a 5" tip.

[suburbanK-2500HD]

With the Banks turbo I would stick with the Banks XOver pipe.

The 3-1/2 Banks system is what is on my DaHooooley and it flows fine.

A low restriction Banks muffler is great, the sound is nice but not anoying.

The 4" is overkill on a 6.2/6.5 as these engine simply can't take advantage of the flow that the 4 inch can support.

A good clean full 3-1/2" will allow all the air that your gonna push

The stock late model 6.5td's as Maverick mentioned have a 2-7/8 or close plus the Cat/soot trap (Ugly cork) and a restrictive muffler.

The urge to go 4" and look way cool is tempting I know but the return on the $$$$ is probably not even worth a passing glance.

Personally I would at least use a low restriction muffler like the Banks one.

Straight pipes on these things sound Nasty and get anoying on a trip.

Stacks with an echo chamber box in the bed that has a couple baffles in it are not too bad but overall the best choice me thinks is a Muffler.


Have fun and keep us posted


Robyn


i totally agree, 4" straight will give you headake, and too much rumbling.
specially when doing trips like Robyn says.

3,5 flows good, and sounds great. Turbo whisling and all. :)

[Mikey von]

I plan on doing 3.5" straight with a 3" down pipe. I had forgotten that my used banks set-up came with the banks x-over. I will run that.

I am going to start off straight pipe and run from there. If I need to add a muffler I will do it.