I am interested to know if anyone has put twin turbos on a 8.1? I have 2001 2500HD with an allison tranny and am primarily looking for towing power. I pull a 48ft gooseneck with around 13,000 pounds. I'm not nessesarily looking for max power at high RPM (but wouldn't mind smacking a muskrat every now and then either) and would like to know what size turbos I should look for? How much boost is possible with the stock setup? Any guidence would help.

 

I've heard of someone doing a twin rear mount on a 8.1l but never saw results. A single is more efficient then twins. STS has a kit that comes with a 67mm turbo. This kit has made 425wph, 600wtq @ 6 psi. I have STS kit with 76mm turbo I'm installing on my 03' right now. I plan on pushing this to the limits of the turbo or the engine.

 

Tie rod is really the guy that knows this 8.1L stuff.

Months ago something was floating around about a compound twin turbo set up that was going on a motor home. If i can find it ill post the link..

If you havent done it yet. Do all the bolt on's first. Headers, intake, exhaust, then get the computer tuned. I picked up a lot doing this on the suburban.. .

 

I had planned on mounting the turbos at the end of a set of shorty headers. What makes a single more efficient than twins?

 

It really depends on the size of the turbos and what your goals are.

Two real small turbos would spool like one big turbo, Unless you figured out how to run them in a compound set up. Then you could use a real small one that spool about 1800 rpms and fall off about 3K rpms. The boost from that turbo would feed the larger turbo and take over from 3-5K... but that would be a huge pain in the but.

You could do a turbo on each side like you suggested and it would work well. Only problem with two is your doubling your cost.. you will need two of most parts...

Raylar makes a nice head and cam package. they say it takes you 500-525 crank hp and 600lbt... That deal is about $4k...

Tie rods has run them all, nirtorus, head & cam. head & cam with nitrous, then the turbo..

STS is a good product, Brad a friend of mine, has a camaro in the low 11's on 6 psi, and his dad's 5.3L silverado put down 390 whp and 480lbtq on 6 psi. The only draw back to the STS is price, When i called last month they quoted me $11K for a STS kit. Im not sure if got ahold of a retard or what.

I dont know where your located becuase it's not in your aviator, but trick performace has been itching to do a 8.1L turbo truck. They are just to far away for me to make it out there...

http://www.trickperformanceproducts.com/

 

8.1 and a turbo should be pretty sweet.

 

STS quoted me a price of about 6,000 for a kit on my 08 sierra.

 

thats about right. The 8.1L they say needs a lot more crap. I cant find the info they sent but it was like dual waste gates, blow off valves, fuel syustem etc etc... they also only rate them at 120whp and 180wtq increase.

 

My dad built a custom twin rear mount setup on his 8.1l 2500HD with the allison trans. The turbos are 6*mm turbonetics, can't remember the a/r ratio though. He usually runs 5psi normally and 10 on the higher setting until recently he went up to a 8psi spring and runs up to 15psi for brief hits. The damn truck moves out thats for sure. Boost builds kind of slow but not too slow. He also pulls a fifth wheel travel trailer fairly often with it as well. It was tunned by Nelson Performance on here. If I remember correctly according to my aeroforce scan gauge the truck was making in excess of 530rwhp! and that was on the 10psi setting with a max of like 7* of timing. Conservative tune I know but for obviouse reasons.

Here are some old mock up pics.

 

damn!!!