66deuce

iTrader: (1)

what makes an L92 cam different?valve events,the lobes themselves,or a combo of both?not that i want to grind my own cam,just curious..

Blindmelon

The only person that seems to have it nailed for the L92/cam combo for LS2 is Rick at Synergy. Look in the dyno section for his post. He is getting 480's to the wheels & 470's ft. lbs. big power from the bottom with his grind he worked out. Most the guy's are trying to use LS1 tech & it doesn't work losing low end & mids. The big intake needs the exhaust to have a lot of velocity to prevent reversion at lower rpm's. It likes to suck a lot of fuel & air into a clean cylinder at low & mids for bottom end power not just high peak numbers on a dyno. He is getting more with less (mild lift & duration) his cam is about $425 cheaper then trying others that won't work well with L92 heads.
Unless you have a trailer car & over 4,000 stall. That is my next purchase for my stage 2 L92 heads. LOL

Louis

iTrader: (7)

Rick has it down, as do we. He is much more conservative with his grinds because he is a big fan of area under the curve.

The problem with the L92s is getting the low end to work right. Its a big port, and depending on the application, its tough to get them to drive right. Too much cam, and it lacks a LOT of low end, not enough, and you dont make power. The ports are very lazy, and with people trying to put them on small cube stuff, the cam can be touchy.

03 BUSA

iTrader: (25)

Louis, I sent you an e-mail regarding you L92 cam info. Thanks

Blindmelon

For sure LGM (Louis) knows LS3/L92 cam's. I have been watching the big numbers you guys are getting on the LS3 Vettes. You guys at the top of your game on L92/LS3 stuff for sure. I have a 4400 lb SS Trailblazer that run's 112 to 114 mph @ 12.12 stock bolt-on's plus nitrous so I need a lot of low/mids torque to get this brick moving. Reason for Ricks Synergy cam (baby cam) big numbers. It is a DD so I want good street manors. If I get my dream Vette next year it will go to LGM for the package you guy's are doing. You guys have a LS2 SS Trailblazer cam you like?

WizeAss

iTrader: (5)

now take all that the Rick and Louis know..... and put it in my equation and common theory goes bye bye.

4.030 bore/4.000 stroke, A3, 4k+stall, Nitrous, Carb Style Single Plane Intake, Ported LS3/L92 heads.


what do you get? (besides a slow car NA ) Totally different cam specs and ideas. I must make the perfect guinnea pig for cammin a 08 Vette headed F-body!

JDP

iTrader: (21)

i had Patrick G spec out my nitrous cam for my L92 headed car, and i feel like its a succesfull grind, because im at 505 at the wheels, and i still have 1 3/4" headers, and its on a stock L76 intake. the heads flow 360cfm but with the intake on they are only at 310, so its still getting choked, so there is still a good amount left on the table with my setup

8ByGoat

iTrader: (2)

Actually there is someone else but they are not a sponsor on this board. While those are good numbers Synergy is getting those are on Vets-there is a shop here in GA that is getting those numbers from GTO's.

66deuce

iTrader: (1)

there are several shops that have it figured out..i know that..but is anybody willing to share the reasons why an L92 cam is different?

94 guy

iTrader: (125)

i thought futral done a tbss for a guy out of miss. that guy said he went 12 teens on motor with the l92's and a 22x cam.

Asmodeus

Because of the L92 heads and the massive size of the intake runner, and the poor flow of the exhaust ports.

Blindmelon

The large intakes & small exhaust are by GM design to get velocity up to clean cylinders contamination out (reversion) to take a full A/F charge VIA large intake.
This was found to give them 30 hp over a larger exhaust. Everyone is thinking old school & bumping the exhaust duration & lift. This makes it pull in the upper rpm's & dead in the low mids. Big *** LS1 style cams kill them more or trucks & heavy auto's.
Also makes it not street friendly. Everyone wants the biggest??? The guy's with SS Trailblazer LS2 are kicking it better with something more like GT2-3. Synergy has a sweet take on the good street cam for sure. Dyno numbers above 6,500 style cams are being ripped by smaller correct cams. Unless you want a trailer car or a bad mannered street unfriendly car/truck. GM could have given you 30 hp less with the old thinking.

66deuce

iTrader: (1)

i'm trying to get my thinking straight on this..how do you get the velocity up with big ports and intake valves?

Asmodeus

You don't really. You can compensate by having an earlier ICL. Velocity will also increase with higher RPM's or more stroke (moving the piston faster).

66deuce

iTrader: (1)

i know that,lol..tell me about the cam..different VEs,lobe profile,etc..as compared to an LS1 cam..

Blindmelon

The smaller exhaust valves & port design increase the velocity into the exhaust helping to clear all the spent gasses out preventing reversion at lower rpm. So the large intake valve lets more A/F fill a cleaner cylinder making more power in the low or mids. This is not a issue at higher rpm's but a lot of the mid rpm's are seen on heavy trucks or SUV's. That makes it a great street cam from the dig & up. It along with a 3,000 stall makes it a great street ride that run's fast at the track also. I will be running mid to low 11's with this combo in a 4600 lb SUV & drive it home from the track.

White_Hawk

iTrader: (3)

I asked an old school cam guy about "Lazy Ports" in general. He said that the best way to get the velocity up was to open the intake later. That would explain why lower durations are working well - they open the intake later than a bigger lobe on the same centerline.

-Geoff

66deuce

iTrader: (1)

i read that on here in another thread..i'm assuming that,to a point,there is more of a vacum when the piston is farther down the bore on the intake stroke..and maybe i'm wrong,but by having a lobe that opens the intake a little slower could help the velocity as well..
anybody else want to chime in?

66deuce

iTrader: (1)

ok,i see what your saying now..
earlier you mentioned GM gaining 30 hp with the smaller exhaust valve..
was this in an article you read somewhere?or somebody from GM that you talked to?

Blindmelon

It was a article in a Corvette mag about the LS3 motor which has the same heads as the L92. They said GM was trying different combo's with the cam's & new heads to make it cleaner burning low/mids on up. They found a extra 30 hp because of velocity
port design & cam design. Getting a better cleaner cylinder & using the large intake for a clean full A/F charge. That is why the 3 crate motors for the LS3 coming out soon go up to 515 hp N/A with cam & compression changes. Bigger is not better the spec's on the 515 hp motor are mild lifts more in lobe design & ramps with mild duration. Take what they are doing to get a good combo that has street manners VIA what Rick at Synergy is doing with his cam design. Again guy's this is a better head then given credit if you pick the correct cam which most don't that I have seen. I will be running the Synergy cam from my research it is dead on. After Jan I will be posting feed-back.