625fwhp for only $22,000 , now thats a deal!

 

paying for the name, plus the engine come all pimp out, shiny stuff.

Anyway's I am sorry for recent thread whoring. I stop for now.

I thought I might see if some people on here to use their trucks(4x4) as trucks not cars.

Oh somebody better tell Tierod, that the bottom end on his beast is going to fall out.

 

If you guys need more info on the weaknesses of the 8.1 go to www.hotboat.com/forums and you will find a wealth of knowledge on what the 8.1 will and won't take. BTW indexing a block is NOT cheap and stroking the 8.1 any further will create undesireable rod angles and prematurely wear out the block. In other words it would be okay for race applications but not for street. the 8.1 has a very HEAVY rotating assembly and it will not like high rpm. If you plan to spin that thing up you really need a FORGED crank a good set of I-beam rods and FORGED pistons, not to mention a studded bottom end. I still would not put it under pressure because of the weak pistons I mentioned earlier. the forged pistons will take a little more abuse. I think it would be totally doable to build a N/A 8.1 that would make some nice hp/tq maybe even 500 fwhp.

I think you should maybe even start with a marine version of the engine and ditch the truck version. the 496HO comes from mercruiser with 375hp I believe and the 496MAG is 425hp I think. Of course you would need to swap the cam out for a street cam as marine cams have a completely different profile and are designed to operate in a different range.

As mentioned the 572 is NOT derived from the same block/head combination as the 8.1. Although in all reality the 572 would be a better bang for the buck in the end when compared to the a heavily modified 8.1. And they will bolt up the same. 620+ hp for 12k+ is pretty cheap.

 

there are more 2 bolt mains running down the dragstrip than 4 bolt mains. FACT. however, I bet that 2 bolt bottom end was studded to help prevent cap walking. people don't break main caps. I have never heard of this happening. they do however walk caps and spin bearing because of it. I would say the weakness is not in the block but yet in the rotating assembly and more specifically the pistons. this is strictly based on what I have seen and not anything published. I think the 8.1 is a great engine just from my experience it does not like boost. Some engines will take it some won't.

 

Marine version and Truck verison are one in the same. Just different cams and marine version is speed denstiy ecm, plus no throttle by wire. the Hp3 version had different internal parts.

 

I would think the ecm would be easier to tune on the marine version with less sensors to deal with. and no emmisions CRAP on the marine version.

 

yep no maf. and no egr

 

Hmmmm...... I remember mtomac on the diesel boards telling me the exact same thing last year!!!


Anyways, who cares - back to the original topic...

 

8100Hammer, against my better judgement to engage you at all, but I did some more reading. I found a guy on the MEgasquirt website who installed a ZZ502 cam, ARP rocker studs and aluminum roller rockers, on a stock internals 8.1 Vortec engine. He's a megasquirt guru and knows what he is doing with the tuning. He spit two rods out the bottom end, and his plans now call for putting a 6.0 motor in the truck. FYI. He doesn't think too much of stock 8.1s.

The link you posted is a totally built marine engine. Making less power than a turbo'd 6.0 will make (their numbers are at the crankshaft). For $22,000. If the firing order changes in the motor you discuss, then it has a differnt crankshaft, right? You are talking about two motors with BIG DOLLAR internals. Huge difference to a stock internal LS1...

Sure, you can spend a TON of money and have a nice 8100 setup, but I think you need to compare apples to apples - go ahead and put an 8100 in a half ton if you like, but make sure you let us know your total cost. Because ANYONE with a ton of money can do anything they like. Anyone with no money and a big mouth can talk about doing what they want to do, but few people actually COMPLETE a high dollar, medium-reward project like this - so we'd love to hear about it when you are done. I actually like projects with a little weirdness to them, so I say go for it!!

Also, it's "Cummins." Not "Cummings." FYI.

-scott

 

actually the 8.1 is a GEN III motor