Hit Man X

For a moment disregard fuel economy, oil consumption, and cost okay?

Here is what I was thinking about today: Could a fully built 8.1 make more power than a Duramax?

Okay lets take a Duramax fully done:
Programming - not just a box, full custom tune
Exhaust - 4" turbo back
Intake - Open filter
Converter - Lower stall ~1200-1500rpms
Valve Body - Shift kit for Allison
Injectors - As large as attainable
Propane - 100hp worth
Nitrous - 150-200hp shot depending on fuel input
Manifolds - Ported and JetHot 2000
Down and Up pipes - JetHot 2000
Heads - Ported and valve job
Turbo - JetHot 2000 on exhaust housing, ported, balanced

Now 8.1:
Heads - Ported, valve job, roller rockers
Merlin block - 4.5" x 4.5" = 572cubes OR 4.6" x 4.75" = 632cubes! I don't think stock block can go to a .350" overbore...this block will work as long as it is true that GM's 8.1 block is a derivative of the Vortec 454.
Cam - 242/250 maybe. 600cubes will eat some cam
Internals - Billet crank, billet rods, forged pistons
Full length headers - 2 or 2.25 primaries w/ 3.5-4" duals
Converter - Higher stall ~2400-2800
Valve Body - Shift kit
Boost - Intercooled Whipple. Could it blow 7psi into 9.4 to 10.4 liters?

Now...all else being equal what is a better setup? What do you think would make more power? Obviously the 8.1 would need a trick fuel system, the diffs would have to get Eaton's, and the Allison would need a full prep @ $5700 alone!

gator's 99TA

iTrader: (2)

um, i think you should add more variables!

XLR8NSS

iTrader: (4)

Duramax is gonna make more power. The whipple WILL be the limiting factor on a BIG motor that can handle boost.

Hasn't a duramax already made over 800hp and UNGODLY ft-lbs of torque <---What the dyno really printed out.

The 2.2 Whipple in the 8.1 kit won't flow that much air and on a forced induction motor the blower(turbo or otherwise) is the limiting factor for total airflow into the motor.

XLR8NSS

iTrader: (4)

What size turbo is on the Duramax anyway?

Slowverado

Quadzilla here in Lake Worth has several dmaxs running around w/over 500rwhp...Quad's is over 600 w/o nitrous or propane.

XLR8NSS

iTrader: (4)

Matt - Find out what size turbo they have for us. It'll be your good deed of the day tomorrow.

Slowverado

Quad's is twin garrets....do you want to know the stock size?

gator's 99TA

iTrader: (2)

yea tell us the stock turbo size, or anything you can find out about that motor. i know it is 32 valve aluminum head, 18.5/1 compression (low for a diesel), and a pretty big turbo. we spin our 03 to around 26 psi on level for hot juice box.

10.5 Dave

iTrader: (5)

One thing you forgot is the 8.1 is a poor choice for a hot rod engine.It's tiny ports are great for torque but bad for high rpm hp.A Dmax would be a much cheaper way to go.I know you said screw fuel economy but a 8.1 with what you described would get probably 5-6 mpg,premium fuel no less,while the Dmax will stomp it and get 18-20 mpg on cheap #2.If you could get big power out of a 8.1 the Allison would need the same upgrades as the diesels.If someone wanted to spend 30k to build what you described it could be done,it's just not practical.

1BADHD

The MAX will put the torque through the roof. The Rat would be put under the table.