Super Charger vs. Head problem
Thread Starter
Team Owner
Joined: Jun 1999
Posts: 27,317
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Super Charger vs. Head problem
If you've followed my thread in C4 Tech, you know I'm going to beef up my 91 L98.
A supporting tuner is suggesting a super charger instead of the ram.
I'm on the fence with this one. But here's the 'dilema'.
I'm told that the current heads are good for up to 350 hp.
The super charger would probably exceed 350 hp. Even so, the tuner says I don't need to change the heads.
Can someone explain this to me?
Thanks
A supporting tuner is suggesting a super charger instead of the ram.
I'm on the fence with this one. But here's the 'dilema'.
I'm told that the current heads are good for up to 350 hp.
The super charger would probably exceed 350 hp. Even so, the tuner says I don't need to change the heads.
Can someone explain this to me?
Thanks
Team Owner
Joined: Aug 2000
Posts: 24,125
Likes: 3
St. Jude Donor '14
Re: Super Charger vs. Head problem (Sensei Earl)
On a normally aspirated engine, the heads will flow according to their capabilities. With a supercharger or turbo the air is forced in, so head flow characteristics aren't crucial. Better flow = more power.
Melting Slicks
Joined: Mar 2001
Posts: 2,149
Likes: 303
From: Timra, Sweden
Re: Super Charger vs. Head problem (Sensei Earl)
It is the pressure differance between the manifold and cylinder that forces the air in. With a better flowing head you will get more air in with the same force.
With a supercharger or a turbo you will increase the pressure in the manifold, and the pressure differance to the cylinder will be greater. The result is that more force is used to push the air in so the head will flow more.
With a supercharger or a turbo you will increase the pressure in the manifold, and the pressure differance to the cylinder will be greater. The result is that more force is used to push the air in so the head will flow more.
Drifting
Joined: Feb 2002
Posts: 1,937
Likes: 2
From: Arvada CO
Re: Super Charger vs. Head problem (8388)
Yes i agree you are forcing air into the motor...i have a 1991 Vette and some days i get 10lbs of boost and some days 7psi (keep in mind i am at a mile high) and before that i was running a 150shot with 10psi with over 100K on my motor so i am sure that the heads are capaible of over 350hp well atleast on my car??? i have a stock block and stock heads just headers and airfoil?
:p:
On a normally aspirated engine, the heads will flow according to their capabilities. With a supercharger or turbo the air is forced in, so head flow characteristics aren't crucial. Better flow = more power.
Safety Car
Joined: Aug 1999
Posts: 4,862
Likes: 118
From: Texas
Re: Super Charger vs. Head problem (Sensei Earl)
The L98 heads will work fine although they will be better if you port the exhaust side. Supercharged engines flow a lot of air. The intake side isn't a problem because of the positive manifold pressure. The exhaust side will be the restriction in flow with the supercharger so it will need porting and a free breathing exhaust system.
Melting Slicks
Joined: Mar 2001
Posts: 2,149
Likes: 303
From: Timra, Sweden
Re: Super Charger vs. Head problem (RatRacer)
True, that is why blower cams have more exhaust than intake too. Most (all) heads are flowbalanced for NA and blower cams compensate for that.
Team Owner
Joined: Sep 2001
Posts: 62,137
Likes: 1,727
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: Super Charger vs. Head problem (JoBy)
I would still do the SR, but what they have said is correct. Its 350hp NA, not boosted. The SC is forcing air into the chamber, instead of the engine sucking it in.
Melting Slicks
Joined: May 2000
Posts: 2,148
Likes: 1
From: Chandler AZ
Re: Super Charger vs. Head problem (vader86)
Yeah the stock exhaust ports will be horribly inadequate with a blower; the intake is horribly inadequate too, but the blower will stuff the air in anyway. I don't think you need the SuperRam with a blower and stock heads; the heads will be the biggest barrier to power output. I would upgrade the heads first, then move up to the SR when finances dictate. Also new heads could lower the compression a bit and let you run more boost safely.
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