I was told to use a "2.8/3.1 TBI throttle body (requires an S-10 computer)"
First off the 3.1 only came with a TBI unit on the first generation of those slant nose minivans I think. And why would I choke the engine like that when I already have port injection plans in motion? AND the 2.8 and 3.1 engines are both v-6 engines, my 2.5 is a 4cyl engine, am I supposed to use a the 4cyl s-10 computer? Because a v-6 s-10 computer wouldn't be happy trying to run a 4 cylinder engine with a dis unit when it was built for a v-6 with a distributor. And all of the research I have done so far shows that the s-10 4 cyl only came with a distributor, I have a dis unit and I want to keep it. Could I probably reprogram a ecm? I don't know. But why add even more work to the project"
Then I get jewels like these....
1)"Use an S-10 crank"
---- I've seen pictures of both cranks and the differences are minimal. Both use the same bearings, so the journal sizes are the same. Later years did have counter weights where mine does not, this probably was done to try and smooth out the engine since they do not have balance shafts. But since I know someone that rebuilds and balances cranks and rotating assemblies for a living I asked him, and he said that on a four cylinder engine the crankthrows offset each other so adding crankthrow counter weights to a four cylinder does not add strength just weight. The extra weight would be good if I wanted to balance the engine to spin over 6000, but i don't plan to go over 5500. So the best way to balance my engine would be to weight match the pistons and weight match the rods, then balance the crank with the flywheel and balancer installed. Yes some s-10 blocks are stronger (vin "a") I believe, but that's because that engine was designed to carry more of a load (it's a truck) and the timing curve is too aggressive. So the block had to be able to handle the detonation and stress. And I can't find proof that I can swap blocks, again my vir "r" is a dis type block and the vin "a" uses a distributor, and I don't know if the crank sensor hole is in the side of the vin "a" block or not.
2)"build a long tube equal length header"
---- Duh, I'm building a turbo motor, where should I put the turbo? under the engine?
3)"You would be better off (and gain as much power) by strengthening the engines weak points and remaining normally aspirated"
----Really, "gain as much power"???? best setup I can put together and stay under 5500 rpm puts me at 120hp at the crank, now if I wanted to spin it to say 7000 then yeah I could build a 180hp motor. But I will agree that at 7000 rpm I'm looking at a very very very short lived motor. And the fact the the timing curve in the ECM is so aggressive that it always runs on the edge of detonation is o.k. if I did it their way?
4)"Go for the Murcury Marine version of the 2.5 which is a 3.0. Port the heads and stay at 7psi or below"
----Port the heads? I only have one. Why stay below 7psi, I thought these cranks are the answer to all of our prayers. But as you will read a little farther down the rest of this idea will be laid to rest.
5)"The stock crank will fly apart at 150hp, its trash. A marine 3.0 crank(with some machining, although I dont think it will work in a FWD) will hold up to 200+hp pretty well and be reliable and cheap. Dont bother with the stock rotating assembly on the duke, the turbo will destroy it pretty quick."
----My engine is basically a front wheel drive setup but also listed as rwd so will it work?, and I am not going to use the "stock rotating assembly" I am going to use forged rods and low compression forged pistons to give me a base compression of 7.5 to 8:1
Then I found this on a S-10 forum.......
""""THIS IS THE KEY TO THE 181 CRANKSHAFT CONVERSION IN THE IRON DUKE, you must use at least a 6.200" rod or the engine will self destruct! The reason you need at least 6.200" (6.25" preferably) rod is this: When GM cast the Iron Duke block it shaved weight everywhere it could. One of the places was in the height of the cylinder walls. The 151 only has a 3.00" stroke therefore it only needed a cylinder wall tall enough to accommodate the 3" stroke. When you install the marine 3.6" stroke crank (and rods) in the Iron Duke block you will literally pull the wrist pin to the very bottom of the cylinder wall at the bottom of its stroke. The piston will then "cock" itself in the bore breaking the piston and then probably send the rod through the side of the block. The stock marine 181 rod is only 5.7" (same length as a Small Block Chevy). ...... The cost of having custom rods also played a part in my S10 decision. The later (one piece seal) marine crank will also work but requires extensive machining of the seal and flywheel area (not to mention the filling if the original flywheel bolt holes). I do have another 2.5 that at some time I will do the 181 conversion for a Street Rod or something. I also have a Super Duty engine and parts so I am very familiar with both engines. None of this info is second hand as I have actually "done this myself", along with the hand machining of the custom flywheel.""""So I don't want to go through that.
And Thank you! to people like David Allen who not only took the time to actually read what I posted, but offered constructive ideas, and not being one of those people that ends a non fact filled post with
"Being able to say "I told you so" makes my day!""
