Has anyone here personaly dynoed a L92 with a cam and intake upgrade. I was not impressed by these numbers! I keep hearing nothing but the greatest about them but the dyno showed me otherwise! The motor couldn't make more then 470HP@6,000RPM. Made 5 pulls all the EGT's were good the only thing that impressed me were the BSFC numbers they were very low for a motor not running lean and around 1,250 EGT's. But it was weak on power and torque!

 

Go to the dyno section, there are several threads there about L92 heads.

 

i dont think these heads were designed to be the be all end all of heads. they're a great substitute for someone wanting more power but not looking to break any power records, or is on a tight budget. they do provide a great torque curve and will probably put down good ET's at the track. From what ive seen these heads like a high lift cam and will make power right to 7000 rpms, but i dont think these were meant to compete with 225cc heads, but they're still good for 40whp, which isnt just a peak number.

 

Was this a L92 engine or a set of heads on another engine. I think that the L92 is DOD and has a cam phaser.
If it is a 6.2 L92 engine I am interested in the cam that you chose for your testing. I have a L92 Crate engine and will be testing it and some parts on the dyno when things settle down a bit.

Interested in why your numbers were low.

Thanks

Robin

 

you are not the only one that dyno'd in that ballpark. Hopefully someone will get to the low down on this... If my car does not make over 500...... I am going to be pissed!!

 

i was going to ask if this was a stock cube (6.2 liter) L92 motor as well.from the dyno nos. i've seen,these heads like bigger cubes,as well as a cam with more exh. dur. on a wider LSA.(from the few cam specs i've seen)

 

I did a search and now see that you are indeed testing L92 Engines.

https://ls1tech.com/forums/showthrea...71#post6341371

I am interested in the cam you chose to replace the L92 DOD style cam.

Did you run the L92 Intake or the L76 Intake?

I would think that the 6.2 isn't that much bigger in displacement to make a lot more than the LS2

If you didn't mill the heads a bit, and have a fairly mild cam, a L76 intake I would think that the numbers you got are in the ballpark.

Robin

 

was this an engine dyno or a chassis dyno?

 

Same story here guys. You can't just plop "race" heads on a street engine and expect it to make huge power. Most of us don't have the time or cash to dial in the cam(buy multiple cams) and tweak every last hp out of an engine combo....GM spends a lot of time getting the combo dialed in now a days. Powertrain is king and they make the decisions.

The fast way(average joe way) to making more street power with the L92 heads is to put them on more cubes or spin the damn thing higher. They flow 330cfm for gods sakes...unlimited engine oval track stuff is a little over that on average(360ish)....and they are turning 410cu" engines 7500-8800 rpm to make 650-800hp. The guys making 800hp have nascar sb2.2 heads flowing 400cfm+, going 8000rpm and 14:1 compression.

To make the 500-550 hp mark and stay under 7000rpm, it's going to take either bumping up the compression on the 6.2L or building up a 408+. You can try higher lift on the 6.2 but that’s more than likely just going to bump up the power peak higher in the rpm range to where you lose torque down low.

Given a certain size engine(6.2L) and rpm range, an engine is only going to use so much air(or suck so much air). If you are close to that point(which i think we are here), the only way to get more power is to get better efficiency overall....(IE. Higher compression, synthetic oil, etc.).... this is why everyone was saying that they make more with heads that flow less. The flow was just about right for the engines they had. All else being the same...Big engines can pull air through lower flowing heads(more negative pressure) but smaller engines can't(less negative pressure) and only pull so much negative pressure, hence low air flow requirements.

 

Pretty sure it's an engine dyno. Not too many guys have their cars rigged to data log and get brake specific fuel consumption figures. (nothing is impossible)

Because of the huge difference in head design we are going to spend a bunch of time with cams on the dyno. What works well on the earlier heads probably isn't optimum for the L92 setup.

My goal is to see how much we can squeeze from a mildly modified crate engine.

Robin

 

GM threw out a curve when thy designed the L-92 head their impressive intake flow numbers are negated buy their overly large intake runner volume [260+ cc's] and small exh. flow, [intake to exh. percentage aronnd 70%] using this head needs a rethink and we at T.P.I.S have been through it, we have triied several cam profiles,different cam timing and programming also the chamber is not quite as efficient as a ls-6 [we found a 4 degree increase in timing added 15 hp.] In my opinion this head is a good fit on a 427 ci. engine of larger na. or smaller ci. with a turbo or supercharger.