ausls1

I have done a search, looking for a -9 to -11cc pistons for a ls1 in a 3.905" bore for a 2002 5.7 ls1, struggling to find any one that does one around this size for a 3.905" bore.

looking for around a 9.5:1 CR with 64cc heads.

Are Mahle Motorsport Forged 347cid LS1 Dished Pistons good quality pistons? are they along side wiseco and diamond?

Also will E85 be good on these with twin turbos and if i have to go a slightly higher CR due to pistons would E85 be more suited than 98 octane fuel or much of a muchness?

Aster

iTrader: (9)

The Mahle pistons have a thin ringland compared to the Wisecos. I wouldn't recommend them for a boosted application after my own experience with them. You could likely go with Wiseco's 3.903 bore piston that are -11cc.

killernoodle

Diamond has some in -8.6cc, I'm going to be installing my set in my LS6 soon. They are nice pistons, especially for the money. I got a set for $625 in a group buy here.

72montecarlo

Some of the fastest guys run Mahle pistons

7008ccGTO

Diamond built a forged set for me. Been running 14 psi, 608 whp from a stock bore 346 for over two years now.

NBM-LS1

iTrader: (7)

Weisco has a set of 3.905 w/-12 or -11cc dish. Its what I run with my Ls6 heads and have right around 9.5:1

yelo04goat

iTrader: (11)

wiseco -11cc 3.903 here.. texas speed

Rabble

Yes, but quote me on this. "As I am told," e85 is very knock resistive. It has a higher octane than even race fuel. I believe its around 105-108 depending on the blend. However, gas stations don't have to advertise their blend. It could be from 70% ethanol to the "e85" 85% ethanol. So the octane can and will change from station to station. But once again, I'm not sure if this information is 100% accurate. If someone could chime in on this, it'd be great.

ausls1

cool thanks, i started pulling the motor out today, everyone iv spoken to said the pistons i need is a 3.905" bore for the ls1, but if i can use 3.903" or even the diamond in a -8.6 might be ok, will have another look at wiseco, the only 3.905" bore i remember from wiseco for -11 was on a 4.00" crank/stroke.

oange ss

iTrader: (50)

you need pistons for a 3.905 bore, i.e. the 3.903 pistons..that will be .002 clearance....you cant put a 3.905 piston in a 3.905 bore

ausls1

Oange SS your right, had another look on the Texas speed website and there rotating assemblies say 3.903", when I first looked I was looking at Pontiac which is our monaro as it was closest to what we had and had another look at 97-04 c5 which Is what our Holden commodores/hsv's run here and saw there all 3.903" pistons I need, was told by a performance shop here that 3.905" was the size I need for this same motor, so problem solved.

Texhotrod593

iTrader: (7)

Hey bro, I am using the diamond dished pistons...they work great!! There are many people running Wiseco pistons which are great also. The ones I have is part number 126-11503.

"Diamond Pistons LS1 Forged Dished Piston set w/ -8.6cc Valve Reliefs, 3.905" BORE / 3.622" Stroke / 6.125" Rods / 1.314" Comp Height / .927 x 2.500 Wrist Pins Included"

I also chose these because of the .927 wrist pin...more common. I think its around 9.8 with 64cc and .052 compressed head gaskets. That was with mine checked at .002 out of bore

Good luck!

Adam86

iTrader: (10)

Diamond -9.6cc dished 3.905s here. Put my compression at ~9.4:1 with MLS gaskets and 241 heads.

ausls1

yeh i saw the diamond ones,
i get my tax return back in 2 weeks and there's some extra room in the budget which gives me the room for my original plan of a 383 stroker kit, so will add this on top, which with the -8cc piston gives me a 10.5 CR which not sure how that will go with boost, all though might be good with a whipple or eaton top mount S/C.

or could go to a -11 or -16cc piston to bring the comp ratio to between 10.1-9.6.
still thinking bout running E85 so the higher comp of 10.5 might be ok with that and boost. guess all depends how much boost i decide to run, and what i could run on that CR.

And a beefed up cam to the comp 231/239 113 lsa, i know 114 would be a better cam for FI but the 218/224 114 cam i have atm id say would be too small on a 383 stroker.

ausls1

The factory comp ratio is 10.1:1 so 10.1:1 on the stroker might be good, factory seems to like boost at that comp with a whiple, so could be a good comp ratio yeh?

ls1curt

iTrader: (31)

im running around 10.4 compression and it seems to work.

cadivette

iTrader: (1)

Here is your -11cc piston.....

http://www.texas-speed.com/p-734-wis...22-stroke.aspx

This would give you about 9.57 to 1 comp ratio with 64cc combustion chamber, 4 inch bore .043 thickness gaskets, calculated with the pistons .005 negative deck clearance.

FastKat

iTrader: (10)

Consider the piston material as well. I can't remember exactly which is which - there's a 2### alloy and a 4### alloy typically used for pistons. Most of the forced induction pistons (Diamond, Wiseco, etc) use one of those alloys, and I think Mahle uses the other. It's worth taking a look into the properties of the two different materials to make sure you're getting the one that's best for your application.

ausls1

yeh Diamond and Wiseco use a stronger 2618 forging and Mahle use a 4032,
that's like the rod bolts too ARP 8740 or ARP 2000 for stronger bolts for the connecting rods.
And then depending on Ring's to suit your application be it Nos or forced induction.

Sent Matt at Texas speed an email yesterday or the day before with what i'm after/intentions so hopefully get something back in the next week or so.