C5Natie

In the middle of building, or rebuilding my LS6 motor. I'll talk to the machinist for all full specs and measurements tomorrow. Aiming for 12.1-3:1 compression ratio. The motor will see mostly street but is being built for future high revving trips to the road course with great mid range power coming out of the corner and more top end then you'll see in the straight. Should be fun. Here's how its coming along so far, tell me what you think:

Fast 90mm & LS2 TB both ported
Bosch 40lb fuel injectors
TFS 215cc heads milled to 60cc
Cometics 0.040 mls head gasket
Patriot Extreme Valve Springs, shimmed
Comp Cams custom grind 236/243 112lsa +4 degrees advanced
597/610 lift @ 0.50 (around there, waiting on cam and specs card)
JE forged domed pistons, 6+/-cc's (waiting on all measurements)
JE forged lightweight I beam connecting rod
stock micro polished crank
cleaned and honed LS6 block, still 346ci

Z06_BluByU

I usually read the stock LS6 is tough to beat when it comes to reliability.. but those specs sound like they'll be fun!!

AU N EGL

a few things here:

1- the STOCK LS6 is almost bullet proof

2- Keep you cam lift under .600, or under .588 for any type of reliability. More LSx blow up do to poor cam choices, which is lift above .600

3. TFS are really drag race heads, they may not provide much down low torque on the LS6.

4. Dry sump oiling is almost mandatory for any road racing.
Poor oiling is the other reason LSx road race motors blow up.

Stick with Stock 243 heads, LPE 243, or AFR 205 heads. and head with larger then a 210 runner may not give the down low torque that is need out of corners and UP to speed. For get HIGH RPM HP. That is for drag racing. Long flat torque curves for road racing / road track days.
port air velocity is more important then port volume for any road course engines. Drag racing engines are much different

Cam: the GM Cup cam is the most reliable cam for road racing bar none
239/251 570/570 106 ( Notice the low lift)

or comp has two road racing cams for the LS6
228/232 585/595 110
232/234 595/598 112

Notice all cam lift is UNDER .600 for valve life integrity.

Coyles timing chain
Katech underdrive pully

Comp 918 beehive springs there are a few other very good beehive springs. Dont need double springs for valve life and lift under .600

Fast 92/92 is good. or just the pp LS6 intake is good with at TPIS OVAL tb.

Two KEY Items:


Cam - keep the life under .600 for an LSx or any block of 40X and smaller.
Dry sump. is mandatory for almost any engine except the stock LS6, but can help there too

We have seen or read of too many LS3s go bang and many many LS6s go bang with high lift cams.

Expect to rebuild at a minimum every year, more like every 20-25 hours of use

again the stock LS6 is almost bullet proof. may not have the HIGH Sexy HP, but bullet proof right out of the crate.
Plus one can buy two or three LS6 crate motors for the cost of building a high hp road race / road track day motor.

Ok so much for honesty. take it or leave it.

Dave Deerson

I would stay away from the big compression too. That means race fuel and that can more than double the fuel budget for a track weekend! If just starting out in track days,make the car reliable and inexpensive to run at first,then add power later (if really needed).

AU N EGL

= LS6 Crate motor

and being in CALF, you have the CARB laws, and emission standards that anything other then a stock motor with a small cam most likely will not pass. a full OFF ROAD engine is differnt.

IIRC only the AFR 205 heads have a CARB number

Z06_BluByU

I know nobody has mentioned it in this thread yet... but you might consider a stock LS6 engine..

C5Natie

Well thnx for the honesty guys. Truth is I already had most of those parts. Since I didnt have much money to put into my rebuild after I blew the ring gland on #7 piston, I decided to do a budget build and go high compression. The only new parts are pistons, rods and the cam, which I bought because i got a good deal. I'll run a little race fuel to achieve about 93-94octane, a meth kit might be an order later. As for the cam, actually I belive both lift numbers are below 600 I just cant remember exactly. The cam is a 112 bringing the power band lower unlike a 113-114 cam which is common. The TFS heads? Great power down low and awesome top end. Ive had them almost 2years and the car has been great all throuhout the powerband. Reliability? Well I wont be racing every other weekend and with a forged bottom end it should be safe for quite a while. I got a great tuner and the build will have at least a 1year warranty. I'd be more worried if I were those guys running 8lbs of boost on a stock motor and they seem to last. Its all in how you build it and tune it. If we all ran stock motors how boring would that be?

AU N EGL

get a cam with a lift below .600 and the dry sump.

#7 went do oiling issues.


stoke motors are boring but reliable.

C5Natie

Didnt race the car before so not sure how you figure #7 went because of oil. A stock LS6 isnt dry sump so whats the hurry? I would love a dry sump system but dont have $5k for one right now. BTW, I know personally of bigger more cammed motors way outlasting stockers. Its all how you put it together.

C5Natie

Lets just say I aint sweatn smog. Car is registered with full headers, TFS heads and 228-234 112lsa cam. I'll just say it passed.

imp zog

Even if you go stock LS6, replace the timing chain before you put it in the car with something like the Katech or similar chains; the GM ones are *not* up to road course durability.

stairman

You better plan on a lot more octane than that with 12.5:1, or you will be knocking the top ring land off this time.
Keep the cam lift under .600 or your just beating up the valve train for no good reason, or just plan on rebuilding the valve train every year.

C5Natie

Got one, double roller. Thnx.

C5Natie

Actualy it'll be 12.1:1, 12.3:1 would be the highest. Yeah we'll be seeing what it likes as we tune it but you'll be suprised. The shop has put together a couple of 12:1 motors, including an LS7, that ran really hard on 93. We'll see.

stairman

you got it, not sure why you even asked if you know so much.

C5Natie

Thnx but I know just a little. I know everyone has different ideas and opinions. Still, all opinions are welcomed anyway. This is how we share ideas and info. Just makes it more fun in a few months when I surprise some people with how well my motor is performing. Its all in good fun.


BTW guys, plenty of stock LS6's have gone down racing. That powdered metal used for stock pistons and rods are not that great for racing... unless you drive like my grandpa. Also the only LSx motor Ive seen go down with my own eyes was a stock LS7 Z06 at California speedway on a banked turn. Dry sump right? Anything than can happen, will happen...to anyone(or motor)

Bink

Actually, you have received some excellent advice from the guys here.

Stairman is spot on.

LS7 is not a true dry sump.

Sustained high rpm and lateral Gs are a problem.

The best LSx timing set...i.e. most durable, isn't a double chain.

fwiw.

AU N EGL

When #7 goes, it is an OIL issue or lack of oil.


LS7s are a different story. Stock LS7s have a damp dump not a dry sump.

Zenak

Until you are an amazing driver the less HP the better! HP = Death if you suck as a driver on a road course. Here, read this:

http://forums.corvetteforum.com/auto...e-learned.html

AU N EGL