Has anyone compared L92 heads (ported or non-ported) to ported LS2
(243) heads? Wondering what would be better on a street car only going to a 228/228 or 228/232 cam keeping the lift to a max of 600 and the LSA at 113/114. This is on a 364 Cube motor.

 

ported ls2 is what i would use

 

GMHighTechPerformance.com published an article about six months back comparing LS1 heads from about six vendors on a LS2 engine. Another article about the same time compared L92 and LS1 heads. These articles may help you with your decision.
Personally, I would go with the ported LS2 heads.

 

In your sig I see you have L92s. Not saying you are wrong but why would you prefer the L92s?

 

Just a guess, but he's running a large displacement engine. Ported LS2's would be maxed out, where stock L92's would have room to grow and be ported later (if they're not already) etc.. ?

Mike

 

Check Slp's website. As cast l92's burned fully ported Afr Ls2 heads.

 

l92 have way to big of valves and id go with 1s2 ported

 

That worries me as I would have to be giving up some velocity. This equates to power lost under 3000 RPM which is 95% of DD duties.

 

i know car craft did a comparo on a LQ4 i think. i tried to get the page up but this damn hadji net sucks. the results where fairly good. i think it did loose a little on the bottom but screamed on top.

brody

 

u are correct that why he should go with the L92. I hvae 3 guys running them and all of them are happy with the performance of the heads.

 

I wouldnt worry too much about loss of low end.Gm is using this heads on quite a few vehical lines now, as D/D.

Here is a dyno of the L92/L76 ported combo on a stock LS2 I talked with the cam designer and he said with out the porting mentioned in this thread you would give up about 20-30 on both hp and tq using bone stock units. Look at the tq at 2700rpms this thing isnt losing or giving anything up on the low end. Cam is around 230 intake and 240 exhaust and 113 lobe sep. Thats a pretty mild/mid size LS2 cam IMO.

I'm actually going with this combo for my Z06 but with stock untouched parts .

http://forums.corvetteforum.com/show...ght=ported+L76

 

haha i found it. here you go!

http://www.carcraft.com/techarticles...ads/index.html

brody

 

I have L92's with an XER 228/232 114lsa cam. I had ported (LS2)243's before that and have direct comparisons. First thing is for me to say, no I dont have dyno numbers. I am getting rid of the L92's after the summer but I will play around with the set up first while I contemplate a stroker with which these heads have repeatedly shown that they shine.

They are box stock L92's sourced from Scoggins which was a great place to deal with. The compression is 11:1 and the heads had some very specific and dramatic results that may actually be exactly what you want. My application uses 4.10's on a Z51 C6 geared corvette. That said, I lost a very noticable amount of TQ in the 3k-4k range. I had 461rwhp before the swap and can tell you the top end is far better than before. Drag racers will like these heads since after the launch, you will never be under the 4k mark and therefore have awesome power. For the street driver, the 3k-4k range is passable but doesnt light the tires up the way the higher TQ did from the 243's.

The initial install was very depressing until I noticed the midband took 6 degrees timing over stock in the 3k-4k range. At 4 degrees over stock it still didnt want to break 2nd loose at all when my stock LS2's were getting a spin out of 3rd. Those last 2 degrees woke things up. There isnt a hint of knock retard and I can still push the timing up but wanted to just enjoy the summer where it was. I will try bumping the compression up to 11.5:1 in place of trying more timing in hopes of more 3500rpm TQ.

 

He didnt specify the cam specs in this thread but I beleive he stated 238 intake in another thread. Perhaps he will clarify here.

 

I was told the exact specs but not sure if he wants them posted on here or not.

I will say intake is some where between 230-238 though.

 

my L-92 heads are ported with upgraded valves and they seem to be performing great, especially if you look at the cash savings over heads like afr's.....you will probably lose some torque down low, but you will pick it up on the top end, also one day you may go with a big stroker and can reuse the heads....just my 2 cents...

 

i think with the L92 heads your cam selection will be somewhat different than what you would use for an LS2/LS6 head..not saying you still wouldn't lose a little low end TQ,but paired with a cam ground specifically for the L92s the results would be better..in a few months i think we'll see better results from the L92s,there's still a lot of learning to do to see what works best with them..

 

In defense of the L92's, low end TQ isnt really where you loose TQ. At 2700 is it very good actually on most graphs I've seen on a 6 liter. I will call it a mid band dip but a lot goes on in that 3k-4k rpm range.

The prior reference to cost savings by the ported set owner above is common. The basic L92/L76 set-up is around 1250 and the springs are 400-600 unless you want to cheap out with some sad springs. With them being ported 425 for the CNC port job and a valve job at 175 brings the total to 1250+400+425+175= 2250 to 2450 depending on springs. Keep in mind this is with a 530 dollar manifold set-up that you may not need (injectors, fuel rail, TB) and you can also get a ported set directly from WCC for 1700-2000 depending on options. That said if you go with a FAST manifold and AFR's (just randomly picking an option) its at 1000 more for the midband restoration. PatrickG used this combo for 508 rwhp with a 238(?) cam.

The box stock L92 set-up, especially if you have springs already up to the task, makes it more like an 1600 dollar savings. Application specific buyers may opt to simply bolt on the heads stock and get west coast cyliner heads to do an exchange set at a later date for more gains.

Be aware they take a lot of timing and require notching pistons for any real world cam if you want 470+ to the wheels. Renting the notching tool and using it (or paying for its use) will cost 150-200 for the rental (LG's current price is 200 plus shipping) and the labor isnt free. Once at 228 intake duration you will need to fly-cut if you use a decenet static compression from milling the heads and/or thinner gaskets. Stroker TQ isnt going to be there when you fire it up on a 6 liter. Dont expect anything good down low with low compression. Until 4k most people will question if there was any power gain at all at 10.4:1.

If its a street car, nothing will compare to the 205cc runners in the AFR's. Keep in mind, you get what you pay for. The low end driveability with a 260-268cc head isnt anything like a 205-220cc runner.

None of these comments apply to use on strokers and if there is an upgrade path in your future, factor that in. These heads shine on a 4" stroke. Peak power doenst seem to be as good as FAST/cathedral head power but the intake manifold may be the blame. I'm sure a FAST for the L76 application will be here one day with the number of cars now using the L92/LS3 platform.

 

seems like it depends alot on your power goals and budget...i'd think that if you were looking for around 450whp out of a heads/cam package ported 243's would be perfect, and cost much less than a full L92/L76 setup. like these guys said if you plan on stroking the motor out to big cubes and making 500+ than the L92's are a great budget head that make good power up top.

 

I beleive for the 6 liter owners, LG has a cam only set-up with stock unported heads that hit 450rwhp with the FAST manifold.