LS2 - L92 or std Heads?

[MARS]

Looking at updating Heads on my LS2. Not sure which way to go. Either upgraded to L92 heads and manifold or modify std LS2 heads with manifold.
At the same time I will be ugrading to OTR, as it is using std intake.
Current mods;
Cam not sure exactly spec, but in 240's duration
3.9's
1 7/8 primaries and dual 3"" exhaust.(Diffilipo)
Tex clutch.
What I am after is utilising the cam, with a broad torque range, a good street performance car, not just a high dyno reading at upper rev range.
Just not 100% sure what the L92 heads will be like, as port volume is larger and therefore air velocities will not be as good down low.
Thanks for any relevant feed back.

[SVNLTR]

the ls2 243 is a very good head when done in the right area's

[255-LS1]

What would the cost of STD L92s and manifold be

VS

your existing 243 heads ported with a fast 90 and N/W 90mm TB

and what would yeild more gains ($/KW, drivability) on this combo

[rosey]

I would guess since you're going a big cam you may be better off porting your 243 castings, from what I've heard the big valves on L92's don't leave much room for a big duration stick. Just a guess anyway :)

[MARS]

There must be somebody whos upgrade their LS2 with L92 with a decent size cam. What was driveablity like ?

[hRTHSV]

It that situation I would stick with the Ls2 243 heads simply because with that size cam I don't think you will be able to shave L92 heads to get higher compression like the Ls2 heads which aids torque. I would port the Ls2 heads, fast 92mm - 96mm manifold and port the stock 90mm electronic thorttle body and I would say that cam definitely needs an OTR or at least a better intake than the stock box on the Ls2.

Unless you go a smaller cam I think you would have to fly cut the pistons with the L92 heads.

The Ls2 heads from the US tests I have seen flow about the same as stock L92's up to 3,000rpm but they do miss out a little up top.

[MARS]

Thats what I thinking, a FAST manfold and OTR.

[macca_779]

There must be somebody whos upgrade their LS2 with L92 with a decent size cam. What was driveablity like ?

Ask anyone with an L98 and a half decent size cam. Because that is what your wanting to create.

[rosey]

240's duration
a broad torque range
a good street performance car
not just a high dyno reading at upper rev range

Just reread your original post and I'm not sure if some of these key things can co-exist. May have to go a bit smaller on your cam size to have a nicer street car, as a 240's size cam is leaning a lot more towards top end power, there's always a compromise to be made.

[BLACKVE]

Visit ls1tech the guys in the US love the l92 head swap on a ls2, works well as the ls2 has better comp ratio to begin with. Even speed shops over there supply packages for a complete swap manifold etc. The L92 will kill the old style 243 when done right.

[Car Lo]

Why not talk to a head specislist like Higgins Heads http://www.higginsracedevelopments.com/index.php
If he cannot give you the correct info, none can

[hRTHSV]

Higgins will tell you that the l92 produces more HP than Ls2 with a Fast, I asked him that a good few months back. But the OP talks about not necessarily chasing dyno numbers so really cost wise porting the Ls2 heads is probably the way to go. If you want a bigger dyno number get the L92's and have them ported that's a given, you'll also need a manifold to suit.

[HYMEY]

I like the L92s but given your situation I would call Nathan higgins, you maybe able to get like 320cfm from a small 243 port combined with a 11.5:1 comp and decent cam it will make hp esp with a fast, bottom end will be great. Higgins do a ported 243 ex for around 1500. Again nothing wrong with L92s but you have 243s already and ported right they flow the same with a much smaller runner which is the key to making good power.

[hRTHSV]

Here is the head testing I was talking about, in stock form they are about even till 3200rpm see last page.

http://www.gmhightechperformance.com/tech/0702gm_ls2_engine_l92_heads/specs.html

[MARS]

Thanks for feedback. May need to speak to Nathan re flowing my heads.

[gavlotic]

if ur selling ur current heads for a good price i may be interested.

cheers,

Gav

[bortous]

Hi mate. I have an ls2 myself and have done an l92 head swap on my vz r8 clubbie.
Don't listen to all the bs on here. The l92 heads work a lot better when done right. Gm don't go backwards. Comparing a ported set of ls2 and l92 with the same compression the l92 beats it throughout the whole rev range but from 3000rpm+ leaves it for dead. My heads have 12:1 compression and a 229/242 .631 .631 114lsa *camshaft, and a 102mm fast intake with port matched runners and a ported stock throttle body and port matched extractors. And a 3200rpm stall
converter. I made 348rwkw and 710nm torque at the rear wheels which is huge.
Even with a cam that size I had no piston to valve clearance issues. The key to making big power and great driveability is having the right combination. My car drives very well with very strong torque low down but from 3500+ it goes mental.
Firstly mate, your extractors in the 17/8 size are too big. With only a head and cam package you will lose a lot of low end torque and some mid range power as not enough exhaust velocity will be created at that power level to sustain a low end torque curve. You may get about 3rwkw up top but it's not worth it.
The 1 3/4 size are rated to 650hp flow so that change alone will greatly improve drivability.
I know someone who has a vx ss with heads and cam making 295rwkw. He changed his extractors to the 1 7/8 size after having the 1 3/4 size and he lost so much low end torque and gained 2rwkw up top. At the strip his 60ft time was slower and he gained 1 mph up top. wasted his money as the 1 7/8 size in difilippo are about 1600.
*Difilippo is a great choice in exhaust systems as I had one too and they work well.
If you want your car to drive nicely on the street keep the intake duration at very low 230 with about a 6-8 degree split with the exhaust. Make sure the lsa is about 114 in that size or else it will make the car harder to drive and cam will buck on the highway.
The fast intake is Better and will flow a lot more than a standard one with heads and cam. Plus it will keep the air cooler. They have the 102mm for cathedral port heads too if you decide to keep them. If you do, the headwork is a must as they are very restricted in stock form. They flow about 230cfm but with the porting they go to about *320cfm. If you use that cam you mentioned on stock heads with those large extractors the car will run like crap.
Let me know what you plan to do and if you have any more questions feel free to message me.

[Sonnymad]

Looking at updating Heads on my LS2. Not sure which way to go. Either upgraded to L92 heads and manifold or modify std LS2 heads with manifold.
At the same time I will be ugrading to OTR, as it is using std intake.
Current mods;
Cam not sure exactly spec, but in 240's duration
3.9's
1 7/8 primaries and dual 3"" exhaust.(Diffilipo)
Tex clutch.
What I am after is utilising the cam, with a broad torque range, a good street performance car, not just a high dyno reading at upper rev range.
Just not 100% sure what the L92 heads will be like, as port volume is larger and therefore air velocities will not be as good down low.
Thanks for any relevant feed back.

Hi there,

We have done this swap on many ls2's along with raising the compression and having nathan cnc them for us,you will never get the ls2 head to flow as good as the L92,the perfomance and torque once the L92's are fitted are awsome,as somebody suggested here you can even down size your cam and still make alot of power.If your in sydney i have plenty of samples you can have a listen and go for a ride in.

regards sonny

[Sonnymad]

if ur selling ur current heads for a good price i may be interested.

cheers,

Gav


Gav if your thinking of bolting the 243castings on your 5.7,bad move,they will never feel as sharp on the throttle as a set of good ported 241castings


regards sonny

[flatlinerz]

the ls2 243 is a very good head when done in the right area's

+1

ls2 243 go for it!

[STATIE]

Here is the head testing I was talking about, in stock form they are about even till 3200rpm see last page.

http://www.gmhightechperformance.com/tech/0702gm_ls2_engine_l92_heads/specs.html

If you look hard enough there is also a very interesting comparison between the L98's & some big dollar aftermarket castings too.

The results are very surprising to say the least.
L98's are the best bang for buck head out there at the moment.