So according to http://www.corvettemuseum.com/specs/2006/LS7.shtml
This 500+hp 427ci engine is using cast pistons and 39.7lb/hr injectors. With 90%DC that's like a .56 BSFC. I wouldn't figure at peak HP that the LS7 was that poor at converting fuel into power so with a BSFC of .50 the DC works out to about 80%.
I thought that was interesting.
Maybe the injectors are that large for AE . I wonder why Ford was using 42lb/hr injectors on it's blower motor when it was only putting out 390hp .
When it comes to fuel injectors, bigger IS better. The only time small injectors seem to help is when the owner of a vehicle feels it worth while to under drive the accessories causing the voltage to drop below 12v. THEN I'd still use large injectors and just tune the inj bias vs batt v.
I also doubt GM is using cast aluminum pistons. I bet they're cast but with a strong alloy, or maybe spun cast.

 

The 7,000 RPM redline eats into the available injector time. The titanium con rods has to be one of the better features.

Pistons are probably hypers.

RBob.

 

The way I'd look at this:
~40pph injectors
probably .42 to .43 BSFC (this thing probably makes power VERY efficiently - lightweight everything, dry sump, etc...)
Sequential Injection ~66% max DC desired (valve closed DC).
At 7000 RPM, there's ~17 ms available (*.66dc = 11.2ms).

 

imagine that.. And I stil have some idiot argueing with me on a weekly basis that 24#'s are more than enoguh injector for whatever anyone ever wants to do.

 

according to what ive read, the LS7 is seeing a 95% duty cycle stock...

my personal belief on why they dont have a larger injector, is GM still has to meet all emissions requirements, including idle...

as far as the pistons go, they're just like the rest of the gen III/IV pistons... they're cast, but the alloy is similar to hyper pistons...
however, the LS7 does have redesigned ring lands.. LS1 stock pistons tend to bust around the upper ring land once you go over 550ish RWHP...

 

Not to mention it has to breathe thur cats, and they probably are taking on a whole new life of their own tune wise for those HP levels, and meeting the 100K mile mandate.

 

I don't think the size of the injector and the tuning are the problem anymore.


I've used a few sets of Motron 60+ high impedance injectors and I must say that they have excellent idle and driveabilty qualities. I would dare to say better than 42 SVO's. And I'm talking about 355's with a stock replacement cam and lots of boost.. So you know that they are actually being able to cut down to a low PW.

 

oh i agree.. ive helped setup a set of 60s on someone elses LS1... and they're on my list for when the turbo goes on..


but the engine idling good, and the engine meeting ultra low emissions regulations while idling good are two totally diffrent things.
the racetronix/motron 60s can go to a low enough pulsewidth that it can idle a small displacement motor... but its still rich emissions wise....

 

I didn't have any problems passing a sniffer with mine..

 

you also dont have to meet federal ultra-low-emissions standards.