Bad06vette

If I went with a fairly aggresive cam, say close to the g5x3... maybe not that big. How much power would I be adding with the Cam and L92/L76 combo? Should I look into the head/manifold combo.... Or should I be looking at some better a/m heads, like AFR or something like that?

How much relative horspower would the L92/L76 combo add?

GETUSUMM

My does 435 rwhp thru an auto with L76/L92 combo. It has a 228 R cam, Kooks Lts. Drives like a stock car

Bad06vette

Thats not bad for an A4 with a medium size cam.

I wonder how much power difference it would be between the L76/L92 and say, AFR 225s and a Fast 90.

carlrx7

million dollar question. im torn between them also.

SpinMonster

There is so much more to the set-up when comparing. If you are using out of the box parts and mounting the L92's they wont hit the same numbers. I have hit 460rwhp with milling and thinner gaskets every time I tried with a 228XER cam. You have to fly-cut which isnt a big deal for a real tuner or a ballsy DIY'er. A ported L76 manifold from Cory Harris plus 11.5:1 on my car hit 471 through 4.10's. AFR's do that too with a ported FAST. The cost trade off is how much you pay for fly-cutting and porting.

If you already told yourself the ported L76, fly-cutting, and compression dont matter then also tell yourself that L92's arent for you.

DTE got 470 to the wheels with a 224 cam by cleaning up the manifold and heads.

LG got 490 with their modified version of the G5X3 cam for those heads and Louis did flycut.

I recall seeing north of 490rwhp with AFR's and the G5X3 too from LG.

Its never going to come down to which part is better. Its about the right parts working together and telling yourself not to cut corners with the use of the cheaper head.

Shrike6

LG's package got me to 455/416 with headers.
GM

GETUSUMM

Its an A6 car. I think it has a 228R. If not its a 224R. Heads/intake are ported. My car came from Texas Speed. I am happy with it. I cant wait to put the gas on it. Dual stage plate is on its way ! Good luck with your decision. Just remember that dyno numbers are just that "dyno numbers". Its the combo that gets you down the track faster, not the number.

Bad06vette

How much cutting would have to be done on a 228/236 cam?

I am not really sure about flycutting or notching piston heads.

What about having your own heads p/p? What are the advantages/disadvantages of using your stock heads and having work done on them?

I am not sure if that would be a good idea or not, or if I should look into a second a/m set and keep my stock heads.

andreas g.

Never been a big supporter of L92 heads on a 4 inch bore. You never can really take advantage of the large intake valve. It's shrouded going down the cylinder negating any benefit of the larger intake valve. With a somewhat small cam 224/228 and 215 ET heads, FAST 90 etc, my LS2 made 461rwhp/435rwtq. I am using CNC'ed L92 heads on my stroked forged LS3 427. 4.100 stroke. Because the bore is for the L92 set up. Since I using forged diamond pistons the bore was honed to 4.070. Even better for the larger intake valve. I still think the LS2 works better with the aftermarket 243 style heads. my opinion.

Bad06vette

Those are pretty good numbers for a smaller cam. I am looking into doing a slightly bigger cam, 230s duration, low .600 lift. My goal with H/C on my LS2 would be 475-480 on a good tune with daily drivability. I don't think I could get to that point with the L92/L67 set up or so it seems.

andreas g.

Believe me, mine is a daily driver. That motor got 28 mpg anytime. Drove it 62 miles a day. As for longevity, I took that LS2 motor out with 50,000 on the clock and put it in my son's 2002 C5 and 20,000 miles later it's still going strong. With the cam you looking at 475-480 is very easy to get. Even with my stroker motor my cam choice was on the small side for drivability. It still managed 525rwhp/500rwtq. Got it from the great head work and the extra cubes. I'm all over drivability, no way did I want a paint shaker at idle. Not my cup of tea. I'm sure you'll do just fine with what you choose. Good luck.

Fore58

Bad06vette,

I'm comtemplating on the same set up. I do not rely solely on dyno numbers....just something to analyze at as long as the numbers are not way off. I have watched a video of Evilways 1/4 runs with his L92/L76, 11.37@124.40. And I believe he's around 450rwhp if that. Hence, this is an A6. A M6 may do better is the traps. The trap speed is the real number to me....real horsepower. That's what most of the stock Z06's are running at the track. I don't know anything about head/cam set ups. However, those numbers made by Evilways are stealth and speaks for itself. The real question now is what cam ground I should use. As of now, it seems like the 224/228@114 fits my needs. Just my .02

GETUSUMM

Mine went 11.59 @ 125 with a 1.91 shorttime. That was with a stock torque converter and it was 85 degrees outside. My car still has the stock 2.57 rear too. I think its a great setup

Joe_G

I'm working on setting the money aside to add these heads intake to my setup. Watching my pals Craigster and Spin to see how they do on Craig's setup, then hopefully I'll be next using their post as a guide.

chazc6

I have a 241/244 0.50, 610/614 peak lift. It has good street manners and idles fine, I do get some bucking below 1500 rpm. A little more tuning should eliminate the bucking.
ET 215 Heads
Cam
ported fast intake & more
512 whp 436 wtq
11.18 @ 131.00 milf launch 3100 rpm 1.78 60 ft.
11.04 @ 130.22 mild launch 3200 rpm 1.75 60 ft.
10.? 4200 rpm launch 1.57 60 ft. clutch pedal stuck to floor shifting to 3rd.

SpinMonster

I wasnt either until I saw the results consistent with the 228 cams I used. As I posted above DTE got 470rwhp and 435rwtq with a 224 cam and L92's. Not even hiding behind cost, its keeping up with other set-ups. The differences seem to be what happens when you want to go really big. Having gotten 471 through 4.10's without touching anythng on the heads except milling, I stayed with them seeing the results. I sold the stock parts and my FAST to pay for everything with the L92's and the L76.

I think people have misconceptions about the bore size/shrouding thing. To date the AFR G5X3 combo has done 494 rwhp and the L92's did about the same at LG. I didnt see much of a reason to raise the cost factor. It turned out the bottom end issues where simply using far too low a compression ratio to make a cam fit. My car has no TQ dip between 3k and 4k and thats all I was worried about since it seemed to be a characteristic. If you fly-cut, they will match other set-ups. A full set of L92 parts will set you back about 1000 staying with your existing injectors. Since the stock parts will sell for about 500, the cost of the L76 and L92 is then 500 and makes sense as long as it meets you performance goals. If a 2400 dollar head and a FAST is worth the cost of admission for the cam size you want to use, then its the way you go. For 470rwhp and less I see no reason to pay that money out.

In the event of a failure like a valve breaking, a ETP would need to be replaced at 1200 each and the L92 is 190 each now?

The entire list of parts needed to use them on a 4" bore is:
2 heads: 380
L76: 225
Patriot dual extreme springs: 275 complete
Intake valves: 150
exhaust manley valves:130
Cometic gaskgets (you need new gaskets with any head but here it is):160
Bolt (again you need them for any head): 130



Ported stock heads tend to get soft on the bottom end.

SpinMonster

Third time on this thread: LG got 490rwhp with their G6 cam and L92 heads.

I had 471rwhp 435rwtq through 4.10's (which is 48x's through 3.42's) and the cam was a XER 228/232 114+2. The current cam is a 230/236. I get 28+mpg. I have no porting done except a clean-up of the exhaust runner. The L76 was ported by Cory Harris.

I have no surging or bucking. I have no hot or cold start problems. I see lots of guys with bigger cams make less power. Thye cant run any compression. I have a .060" fly-cut and the heads are milled .030" and a thinner gasket for 11.5:1. The compression was rasied after the dyno and the low end is stronger.

I hated them too until I saw that the cheesy 3k-4k results were simply people not flycutting and bumping compression.

SpinMonster

If you arent fly-cutting, you cant use these heads to thier potential. The compression is the low end.

In fact, the math shows that cam only people using a 234+ XER cam do not have .080" clearance with the stock gasket on an LS3. LG is flycutting to gain the low end.

A note on the silly sized splits: Its a myth. Chevy high performance used a 232/234 cam. Texas speed got 450rwhp on an auto with a 228/228. I hit 470rwhp with a 228/232.

The exhaust runner doesnt have numbers that flow awesome on a bench but a few stats: The AFR's flow 300cfm and match the ETP and trick flow heads cam for cam. There is a velocity issue here and I dont know much about it other than to say one member ran a 10.8 with a LS3 and it was a 6 degree split. Just because a runner doesnt make big peak numbers doesnt mean the head needs a 14 degree split. Dyno Sim software shows 3HP by increasing the exhaust sied flow by 10%. In the end it isnt the big factor needed these grossly over compensated exhaust durations. If anything it simply makes the heads more picky about the exhaust system/headers. Its likely why I picked up so much when I went to the LG headers and the Z06 exhaust.

SpinMonster

131 trap speed is flying. Good job. That cam cant fit with these heads for sure.

The 11degree ETP's fit anything.

GETUSUMM

Are you talking about Jasons LMB coupe? If so, I own that car now. That was also before the ported intake and TB.