Olli Snellman

Last time i touched GM V8 was back in 1995, so i don't know nothing about those newer LS1,LS2 & LS7 engines. I have a background of Classic Chevys (1955-57), so original small block is all i know. Have those newer engines still "old fashioned" con rods, or are they OHC engines?

333pg333

I wish age was synonymous with intelligence lol,...alas, I pursue this 'purity' for a few more builds in the hope of pulling off something a bit special.
Olli, I think you're referring to 'push-rods'.

BC

Well, you'd think so, but we have thinner cylinder walls than you, and less support in the webbing. And cast pistons. But now that we have the 110mm sleeves workable, and a 7L engine config tested, I'm sure someone will do 800. But the trans is not so good at that level, the lore says.

BC

There was a stock block in Green Bay that was above 20psi, and probably close, but he used 951 pistons and some other stuff, but stock otherwise.

special tool

Referring to engines in "PSI" tells you ABSOLUTELY NOTHING about the engine power.
If the engine doesn't breathe well, you don't make **** at 20 psi, and so for the purpose of this conversation (bottom end) 20psi means nothing.
Conversly, if the engine breathes well, and you are using a large turbo or blower, well then you will make some power at the same 20psi.

I have noticed that a lot of the 928ers STILL haven't grasped this concept.

evil 944t

[QUOTE=DVC;4794699] After you've done a few builds (and you get older ha!) I think you become less concerned over the whole "purity" idea and more concerned with performance, reliability, and value.QUOTE]

I think the point that most miss is that reliability comes with a proper build and careful tuning. My stock/chipped 86' went 190k miles and it was driven/DE'ed. Thats pretty good! A Modded engine with better parts should run the same.

BC

I understand your point, but since i have no idea of the CFM that was actually going through the engine, I cannot quote that. You have to understand that people use PSI as a unit of measurement, and they even do it here on the 951 board. It was a large Vortech. I think a T trim or larger. I think that you can assume that our engines breath relatively well with the 4V heads. It has a larger Water to air intercooler that I think has a 1psi drop.

So alot of air was going through the engine. Knowing the configuration, you can clearly see that its not an arbitrary figure.

evil 944t

[QUOTE=BrendanC;4795594]I understand your point, but since i have no idea of the CFM that was actually going through the engine, I cannot quote that. You have to understand that people use PSI as a unit of measurement, and they even do it here on the 951 board. It was a large Vortech. I think a T trim or larger. I think that you can assume that our engines breath relatively well with the 4V heads. It has a larger Water to air intercooler that I think has a 1psi drop. QUOTE]

Well, I assume the worst 928 4v head has to flow 270+. I would guess closer to 300cfm. A 2.5ltr turbo(with a head/cam flowing 250-270cfm can do 400rwhp without any problem so a 5ltr+ should be in that ball park.

BC

I sure as hell hope so.

special tool

I understand it....I just don't like it!

333pg333

110 Sleeves, pretty big?

BC

Quite. But we have big bore spacing, so its very possible with $$$.

Rogue_Ant

20psi tells you that the engine should be ingesting over twice the air/fuel that it would be without forced induction... Of course there is a point of diminishing returns with PSI of boost in regards to head-flow. But so what? Unless the ports are already maxed out at atmospheric pressure, then you WILL make more more power with positive manifold pressure. Hell even old flat-head V-8s make good power increases with Boost.


Rogue

333pg333

I thought we had the same amount of meat on the block, you just have two banks?

TonyG

Does anybody know if a 928 engine will even fit into a 944? I know a 32V is much wider than a LS1, but what about an 8V (not that I'd want a 928 8V....)

TonyG