my point is why would you build an engine to only handle 10psi. if you did a 427 with 9psi which would be amazing to pull that off with the intercooler still in it, isn't that kinda week? if you build an engine for boost and lower the compression to compensate, then 14psi or more should be the goal, not 10 at it's best possible. running the blower all out to just get 9 or 10 just isn't going to cut it. if 10psi is all you would have been looking for then a compression of around 9.5-10.0:1 should be the choice. i'd either raise the compression and just go n/a or get a bigger blower.

 

So blown, How much hp at the wheels did that LPE 427 ever get?

 

I will get the exact numbers next week. I had them in my head but I forgot

 

The thing is, though, high compression, modest boost setups are great on the street. Plenty of low-end throttle response when not under boost, and big area under the curve when you are. As has already been indicated, with the MP112 you may not be able to raise peak HP significantly on a 400 plus cubes stroker, but you can add power and torque everywhere, beyond what you could achieve N/A.

Now, if Eaton is coming out with a bigger blower soon, that could change things significantly...

 

The all wheel drive dyno we use is at W2W. It's brand new and can handle just about anything that you want to put on it. BTW, it's a Mustang dyno.

Thanks

 

i've pointed out the compression issue quite a few times in the LQ9/LQ4 issue. i'll take the higher compression if that's all the boost it can make. on the other hand if you're going to spend the bucks for a forged bottom end, you didn't do it just to throw a little bit of boost to it. you go with a full forged bottom end to work it hard with alot of boost.

 

I definitely see your point. I guess I just see that forged bottom end as allowing you to run a higher combination of boost and compression, i.e. more cylinder pressure.

You're probably right, though. With anything under 10 PSI and even 10-11:1 compression, you probably don't need to go forged, just be careful on the tuning (a/f and timing), watch intake temperatures and run 93-94 octane, which most of us do anyway. Then again if you're boring and stroking to 408 or over anyway, at least stronger rods and pistons may be good insurance, for not that much more money.

All the best - Jeff L.

 

Question about boost:

9psi on a stock cam 6.0, is nowhere near as hard as making 9psi on a 220/220 cammed 6.0.... correct?

I've read that boost is just a measurement of restriction in the intake manifold. The valves being the "gatekeepers"? If those 'gatekeeps' are open longer (stock cam vs 220/220), you're going to have less boost building up in the intake.

Is that good, or is that bad? Do you need boost in the intake to "squirt" the air into the cylinder at a higher pressure..... or would you rather run lower boost and have the air be "pushed" in at a lower psi, but have that air being pushed in during more degrees of crank rotation?

Which yields better cylinder filling?