jimlab

Back on jack stands, right where it belongs.

jimlab

L92 heads and L76 intake...



LS7 intake vs. L76 intake...

KaoticFdR1

So what are the pro's con's with the LS7 intake and heads vs the new parts?

BTW that's sexy as hell!!!

jimlab

Pro: The L92s flow about 335 cfm out of the box, as cast, and can be ported further. They were originally intended for use with the LS2 on the next generation Z06 before GM decided that 427 CID would be required to meet the horsepower and drivability goals and started development of the LS7. The port shape and size of the two are very similar.

Pro: A pair of L92s and an L76 intake cost less than a single assembled LS7 head (~$1,200 vs. ~$1,700). With a cam in the 23x range, the L92/L76 combo can make 550+ horsepower on a bone stock LS2 bottom end.

Con: The L92 heads will not work on an LS1 or LS6 because they require at least a 4.0" bore, and a larger bore would be ideal. However, rumor is that GM is creating an L92-derived head for the LS1/LS6 family of engines.

Con: Currently, the L76 intake (unless you want a carb intake) is the only one that will work with the L92 heads. There are no aftermarket options yet that I know of (but it's only a matter of time).

Con: An LS7 intake and heads will generally make more power than a set of L92 heads and L76 intake, all other factors being equal.

Con: It's claimed that the L76 intake will become a restriction at higher (6,500+) rpm before the LS7 intake because it has less plenum volume, but it has shorter runner lengths, which typically lend themselves more to higher rpm use. I haven't seen a definitive conclusion on this point yet, but it's something to consider.

dradon03

iTrader: (2)

Car is so clean.

KaoticFdR1

wow...i think i just found what i'd like to run...I've already decided to go the piston route but I'm just gonna save some more money and go the LS2 route and use said combo eventually. 550rwhp is my goal for a street car and some road racing. I may even take it to the drag strip every once in a while. Thanks for the info and good luck. Sooooo clean.

chingon

where's the monster thread? I can't seem to find it.

jimlab

Gone. At least half the information in it was obsolete and people were just junking it up with stupid comments.

jimlab

NickSimcheck

I came here for two reasons,

A: I'm lookng at LSx/FD's for sale.

B: To hopefully see Jimlabs LT1/FD run.


Now I see that the LT1 is gone, so I'm assuming you got a crate LS7? Or are you having a LSx made up to your specs?

I gotta give it to you though, nobody knows how to polish, clean, wax, seal, and repeat a turd like you do!

2MCHPWR

iTrader: (2)

looking good. what wheels are they?

jimlab

19" Volk TE-37s, stripped and polished.

Turbo 3

iTrader: (3)

are you planning on staying naturally aspirated? Just curious as you are progressing down the same path I was considering but instead of replacing the intake, going with a Magnuson SC instead.

paul_3rdgen

iTrader: (6)

Looking good Jim, good choice of wheels!

wptrx7

Is it me or does the L76 intake mani have a lower profile than the LS7? Is that the new cradle that you are developing?

Glad to see some progress? How is the new house going? that 47" must be for the garage and not the media room I hope, LOL.

wptrx7

Because you had your thread deleted, your post count went down?

kwman

Jim, good to see some of your progress. That color looks absolutely gorgeous on that car. Hopefully we'll see you over on the V8RX7forum, if those guys will stop slapping each other like girls...anywho. Take care.

-Kwman AKA sweatyK

gnx7

iTrader: (10)

Sounds like you have renewed interest the project again. Good.

The LS7 heads also have 2.20" titanium intake valves which should allow you to spin the motor higher. Out of the box they flow 360cfm...... they can benefit from have the exhaust side ported to balance out the flow.

Bang for the buck the L92/L76 setup is hard to beat.... I'll wager you go with the LS7 stuff.

jimlab

At this point, no, but that could change.

The L76 is very similar to the LS2 intake, except for the port shape and location, and (I believe, don't quote me) larger throttle body opening. It has a 90mm opening like the LS7.

Yep. Almost done.

It's going in the room with the pool table and MAME cabinet, to watch when the 119" screen is rolled up.

Correct. So did the post count of everyone else who posted in that thread.

I'm over there, but just not posting. We'll see how it goes.

I'll wager I don't. BTW, when are you going to posts pics of your engine?

kwman

OFF TOPIC: Oh, and congrats on the Vista stuff BTW , your name is plastered all over the website.

digitalsolo

iTrader: (2)

What do you think of the L92 castings? Mine were some of the best OEM casting I've seen, especially from GM.

Did you take the L76/LS7 pictures? I hadn't seen a direct comparison between them like that before. Thanks for posting those.

One more... (and I may be blind and missed this). Staying with the dry sump?

jimlab

Very nice castings. They look like an aftermarket head before CNC combustion chamber clean-up.

Yep, all my pictures. When I get a chance, I'll measure the intake runner length. I think that despite first appearances, the L76 might have longer runners.

Don't know. Since I won't be road racing, it's not really an issue I'm worried about at the moment. Still trying to decide how many cubes and how low my compression ratio should be.

digitalsolo

iTrader: (2)

How low, as in 10.5, or how low, as in 8.5?

jimlab

8.5ish.

digitalsolo

iTrader: (2)

Ahhh, that leads to the question, belt or exhaust gas driven?