walhan_qtr

I just bought a TT C6 and will be putting new pistons to lower the compression.

info of the car:

- 2006 LS2 M6 C6
- 402ci LS2
- Eagle Crank 4.0"
- Eagle Rods
- Weisco Pistons -4 valve relief
- PRC LS3/L92 Heads 69cc chambers.
- LS3 .051" Head Gaskets.
- 10.8 to 1
- UPP Twin Turbo kit (dont know what turbos yet!)
- custom cam (close to factory Z06 cam, I will get the specs soon)
- Aeromotive eliminator fuel pump (-8 feed, -6 return) with 80# injectors
- running E85 currently
- 820whp on 14psi
- Spec 3+ Clutch w/ Spec Flywheel
- stock tranny/stock rear end

Now my question is since I am changing the pistons, should I stick with the LS2 block or go with an LQ9? I understand the LQ9 weight more ( about 100lbs more?) but I have been told too that its a much stronger block that will handle more boost and more power than the LS2.

I have searched here and came across this great thread
http://forums.corvetteforum.com/c6-f...urability.html

I didnt want to bump an old thread and thought it will be better to start a new one. (and because of the rules)

I am looking to run pump gas (93oct) with methanol (which will only be added for safety, the car will not be tuned on it) and would really like to be in the 800-900whp on 93oct (not sure if possible or how much boost) and maybe 1000+ on race gas? the turbos should be capable and the fuel system should too, but I dont know.

this car is mainly a street car that will see the 1/4 mile probably once/twice a year. all what I care about is straight lines. also it will be driven daily, but def will be running less boost for daily drive (probably have it at 500-600whp for daily use)

now with all that info, what would work better for me and last longer? would you guys recommend the LQ9 or should I keep the LS2 for what im looking for?

from that thread, it looks like the LS2 should still handle 1000+whp with no problems? anyone here over 800whp with an LS2 on pump gas? please post your setup and how long you had it?

I would love to save some weight and also run cooler instead of the heavier and more heat with the Iron block, but I am afraid the LS2 will not handle that much power unless I resleeve it? which will be much more expensive than going with an LQ9?

also what compression should I go with? I was thinking 8.5-9.0 to 1? dont ask me why, but it seems that what people are doing.

and finally, what upgrades do I need for the heads? they have stock valves right now.

Thanks everyone

carlrx7

You already know my setup, so i will just add.

dont go below 9.0 cr.
use LS9 head gaskets and ARP Studs

keep the LS2 block, its not the block that fails, its the rod or piston that try to escape.

Unless your IAT's are alot lower than mine, i would upgrade the intercooler to a Bell core or have one made by ETS to help that 93 octane out from detonating.

e85 and 900 is easy, just turn up the boost and hold on, 93 and 900 with no meth, not easy, low Intake Air temps will be key.

best thing to do is only have the meth come on at 10 or 12psi, that way it only comes on when you really get into it.

-Carl

Mr.Big

LS2 block in my setup, 1000rwhp... You will be totally fine with your goals.

walhan_qtr

Thanks for your post Carl

I will talk to CK about upgrading the intercoolers. that 900whp is just a number that i thought about. I will be fine with 700-800whp as long as its safe or even lower. plus I will try to have three different tunes. one would be I dont know 500-600whp for everyday driving. one would be 700-800whp for some street fun on pump gas, and the last one will be for maybe 900-1000whp with race gas??

as for the meth, I just dont want to tune it on meth so that in case it failed or didnt pump enough, I will still be on the safe side and it wont hurt my motor!?

also I forgot to mention, this car will be used in a very hot climate and weather (may-sep can get as high as 130F in some days!) cools down a bit in oct-nov (in the upper 80s-90s) and Dec-march (low to high 60s)

if course it will driven normally in those hot days (it will not be raced) but thought I will mention this too since its a turbo car.

walhan_qtr

how long have you been running the LS2? problem is you are running E85 which is much better. I will be switching back to 93oct (since E85 is not available where this car will be, otherwise I would have kept it)

would you still recommend the LS2 block? I really need to decide soon so that I can start working on this car.

Thanks for your post.

anyone else??

carlrx7

your best option would be to tune it to 6-8 psi on 93, should make 650 easy.

then turn up the boost and tune it with meth, there are tables in the tune that can be setup to pull timing over certain temp if meth doesn't spray.

that way, the only thing you will need is a meth kit, im assuming a remote kit from AIS, and a retune, then you wont need a new intercooler.

walhan_qtr

thats nice. I had no idea that was possible...

walhan_qtr

what about the heads??? those LS3 heads on the car have stock valves?

walhan_qtr

I am still a little concerned. I have been talking to 3 local shops, one said I will be fine with the LS2, but 2 recommended I go with the LQ9 or get better sleeves. they say the have seen some LS2 blocks with the stock sleeves crack. (they both said it might be in the tune though) but I dont know!!

should I go with darton sleeves on the LS2 block? or just keep it as it is? any input from dallas performance or any of the bigger shops with some higher HP LS2 cars? any other guys here running over 800+whp with an LS2 block?

Thanks

breecher_7

My vote goes for the Iron block... LQ9 or LSX

Corvette-Chris

I plan to build my LS2 block sometime soon (hopefully after my wedding in the spring)...and I've thought about the LS2 vs LQ blocks a lot.

I plan to only hone the cylinder bore out to 4.005" and use a 3.800" stroke crankshaft. This will result in the max amount of sleeve material (other than stock bore) and a shorter stroke which most will agree prolongs the life of the internal parts.

I know the LQ4/9 blocks are very strong, but I don't want the extra weight, nor the extra heat that the iron block will produce.

That's my take on it, but I do look forward to hearing from others.

Mr.Big

That was the reason for my 370... If I want to simulate more cubes....... I add boost!!!

old motorhead

Just a heads up if you do go iron block. The LQ4 and LQ9 use the same block and heads. The LQ4 is just a whole lot more common. It was the base gas engine for 3/4 and 1 ton trucks for a lot of years. LQ9 was used more sparingly in SS, Denali, and some other higher end models. They usually sell for a premium compared to the LQ4's. For what you're doing, there's no use in dropping the extra coin.

Those LS3 heads would sure breathe a whole lot better on top of a bigger bore LS3 block. Just a thought....

master blaster

It looks like u r in colorodo?
If so your elevation will drop u about a full point in compression.
So if ur forged engine is 10.5 up their it's like a 9,5 at sea level.
Pm Spinmonster in co. He knows his stuff!

walhan_qtr

Thanks everyone. I am really leaning toward sleeving the block with darton sleeves like my LS7 block. I dont think I will be doing the LQ block anymore. but I am still open to ideas and your guys opinions.

this car is not staying in Colorado. it will be built here, but then it will be shipped to a sea-level location.

Also I am only changing the pistons, will keep everything else the same. will reuse the same crank, same rods, same heads, probably same cam too.

Thanks

fe9_fe9

I'm currently building a 402 out of an LS2 block with stock LS2 Heads in Saudi. Although I already have my pbc at 0.008, I'm going forward with that as my pistons are ok with this clearance. I thought of re-sleeving the block then I just dropped it and I'm just going to polish it and finish my build.

After lots of research, I figured that the LS2 block will help me in my 1000HP goal. I think you should go ahead without any concerns.

PM me if you need more details.

Faisal

Corvette-Chris

If you're going to sleeve a block, you should really think about doing so to an LS1 block. Steve at RED always says that these blocks are some of the strongest in the LS family due to the solid webbings that the sleeves will sit on....Or something of that nature. Just a heads up.

walhan_qtr

would love to hear more about your build. I will PM you.

but I am shooting for 700-800whp on pump gas. I will do a race gas tune which hopefully will be around 900+whp or maybe 1000whp? who knows!

walhan_qtr

I dont really want to spend a lot of money on this. also if people are running 900-1000whp with stock LS2 and stock sleeves, then the darton sleeves will make it 3X times stronger?? so why go with an LS1??

I mean it will still be better than the stock LS2?

Corvette-Chris

I only brought up re-sleeving a LS1 block because you mentioned it. If you don't want to sleeve a block, just get a LS2 block and build it.