dimetweaker

iTrader: (1)

here is what I posted in the internal tech section

"Well I just got some sad news from the machine shop. My motor is finally together, and just for ***** and giggles, I had them cc's my factory, no machine work L92 heads, only change was to a LS3 intake valve, and they are telling me the heads are 64cc. Is this possible? I have read several times these heads are between 69.5-71cc and they are telling me they are 64cc uncut, untouched. I know this is only a bump from 10.2 to 10.6 on the SCR but I wasnt that thrilled about being at 10.1 for a turbo build. Im running piston/rod kit #k398x7 from wiseco.

http://www.wiseco.com/Catalogs/Automotive/Chevrolet.pdf"



Now I know most of the turbo gurus would be much lower on SCR to start with but this is to be a street motor, and I wanted something with some grunt out of boost. I had planned on trying to be able to run 10lbs on pump gas but now this. If these are in fact 64cc and you were in my shoes, would you pull the heads and go bigger, or just run it since its done and run a little less boost? not sure how I feel at this point, this is my first turbo build and I felt really good about it up to this point. Its not so much about the money, im just not sure if since I was already starting a little higher on SCR is this enough to worry about or should I just run it. The cam in it is a 229/240 on 114+4. Not sure where I end up on DCR, I was taking advice from the big guns for this build so I wouldnt make an error LOL

TurboAv

iTrader: (6)

How far in or out of the hole are the pistons? What thickness is the head gasket you are using? Did you account for those things when you figured out your compression?

TurboS10

iTrader: (12)

That's a big cam for L92's and only a T78.
Those heads flow a lot and only need like a 219/229 to shift at 6500 n/a.

Assuming your cr is accurate.... it looks like you've got a street n/a setup.
Your DCR is 8.3ish. Needs to be 7.5ish for 10psi.
Just get the head chambers worked.
Not sure why "they" spec'd a 3.2 cc dish for a 370 turbo motor.....

<edit> well, 8.3 dcr is about stock, so you could run 7psi or so. Or add meth and go to 10.
I did read some posts by some pro cam spec guys. And they thought a 219 intake lobe was a better idea on a street sq port setup.

dimetweaker

iTrader: (1)

well its actually a 382 not a 370 but the reason being, I wanted to stay slightly higher compression and a little less boost for the street BUT now thats its so much higher, im not sure what I want to do... I feel like the cam might be a poor selection for a turbo, ive seen the same cam cut for a N/A motor myself and it made great power, so I dont know what to expect with turbo behind it, I dont want to get to negative about it until I run it. If it doesnt work out at all ill have to get another one spec'd from another one of the big guys so I can throw another few hundred away. Do you feel like the cam will not net what it could with the turbo, or that its an all around fail? I was very specific with the company that cut the cam that it was going into a 3000lb pump gas turbo truck, stock CR and that it would live most of its life on the street and be driven regularly, and that I would rather sacrifice all out track performance to keep it liveable on the street.

So.jerZ-28

iTrader: (20)

i had same problem.
l92's supposed to be 69-70cc

mine cc'ed @ 64.5cc

ive got a 408 w/ 19cc dished pistons,
i was looking to go 9.1:1
this was my resolve:

cometic 4.080 bore gaskets (since l92 chambers came in at 4.076 edge to edge)

and bumped the thickness of gaskets up to .061" instead of stock .051"

dimetweaker

iTrader: (1)

I have been thinking it over; the motor is already built to drop in, I think im just going to run it as is. Instead of changing gaskets, maybe doing some chamber work, etc. Im going to get in touch with WCCH and send them my other set of L92s once the truck is running, have a full cnc done and chamber work if possible and then slap them on the motor after I figure out how to get the first 700hp to hook in my tiny little truck then I can turn up the wick. Thanks for your input guys.

NemeSS

iTrader: (127)

i would have kept the thinner gasket. and kept improved quench over the
.061 gasket. even in a boosted engine.
but if it was needed to lower the scr, thats fine also

TurboS10

iTrader: (12)

Lots of posts on TTF about squench being a non issue even with the old chambers. Just too much air in there getting squished.