How boost-friendly is the L98?
Thread Starter
Safety Car
Joined: Mar 2002
Posts: 4,975
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From: La Habra Heights CA
How boost-friendly is the L98?
Okay. Let's assume for a moment that the L98's heads, pistons, rods, etc. could handle an incredible amount of boost. So much that the block would crack before anything else. Let's assume, for argument's sake, that this is the case (I know it isn't). How much boost would you be able to throw at it from a S/C or turbocharger with the stock compression ratio? I know, this depends on many things. However, assuming the block is the only concern, how much could you throw at it without cracking or getting very close to cracking the block?
Thank you.
-Jeremy
Thank you.
-Jeremy
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
Re: How boost-friendly is the L98? (Open Headers)
Boost is a relative term. One person producing 6 psi may be pushing 1300 cfm, while someone else pushing 12 psi may only be pushing 1100 cfm. The higher boost may be due to the fact that they are running very restrictive heads and intake. I think what you are asking, is how much HP an L-98 block can handle. Boost tells nothing.
In stock form, I would get concerned at the 450-475 HP mark. Step up to splayed billet mains, professional blueprinting, and a thick deck cylinder head, and I would say that 800 HP is doable. Some people push further, but I think that these are safe guidelines.
BTW, the factory pistons ring lands will lift above 6 psi. I ran for several years, but ran rich. It is not a case of if they will lift, but when they will lift. The blower manufacturers do not offer this info unless you ask. Most times you ask after they have already lifted. Oh well!
Hope this helps,
Aaron
[Modified by AKS Racing, 6:01 PM 6/22/2002]
In stock form, I would get concerned at the 450-475 HP mark. Step up to splayed billet mains, professional blueprinting, and a thick deck cylinder head, and I would say that 800 HP is doable. Some people push further, but I think that these are safe guidelines.
BTW, the factory pistons ring lands will lift above 6 psi. I ran for several years, but ran rich. It is not a case of if they will lift, but when they will lift. The blower manufacturers do not offer this info unless you ask. Most times you ask after they have already lifted. Oh well!
Hope this helps,
Aaron
[Modified by AKS Racing, 6:01 PM 6/22/2002]
Melting Slicks
Joined: May 2000
Posts: 2,148
Likes: 1
From: Chandler AZ
Re: How boost-friendly is the L98? (Open Headers)
Given the highest octane gas, running the highest effective compression ratio (static + boost) said gas allows, and zero-gap rings, you would still never generate cylinder pressures high enough to crack the engine block- assuming it burns smoothly without detonation. If it goes into detonation and you have very strong pistons/rods/crank, you will hammer the main bearings and stretch the caps badly, but still probably never crack a bore (unless maybe you went .090" over on the rebuild).
As you mentioned this is an unrealistic question because so many other things will break first: head gasket, rings, pistons, piston pins, bearings, rod bolts, rods, crank, warped head.
Just as a reference point, people on the Z28 forced induction page are running 18-20psi of boost on stock O-ringed blocks with lowered compression 8.2:1.
As you mentioned this is an unrealistic question because so many other things will break first: head gasket, rings, pistons, piston pins, bearings, rod bolts, rods, crank, warped head.
Just as a reference point, people on the Z28 forced induction page are running 18-20psi of boost on stock O-ringed blocks with lowered compression 8.2:1.
Melting Slicks
Joined: Mar 1999
Posts: 2,535
Likes: 2
From: Rochester NY
Re: How boost-friendly is the L98? (gcrouse)
with the stock shortblock. I would not worry about the block will crack. Your pistons, rods will go before your block. Running boost on stocker, pistons are your main concerns not your block.
Bruce
93LT1 Conv w/ZF6
Blown D1-SC/N2O
ARE built 383ci/Stage II heads
Bruce
93LT1 Conv w/ZF6
Blown D1-SC/N2O
ARE built 383ci/Stage II heads
