Centrifugal Supercharger vs Turbocharger Advice

krico123

Active member
I am looking to make high boost at low RPM (15 - 21 psi) at 3000 to 3500 rpm. Would work you recommend to do this a small turbo like a t3/t4 turbo or a small t4 turbo or a Centrifugal Supercharger.
?s
1: is that to high to shoot for boost at that rpm
2: If you can whats the best power to add to get this power at that power range
3: if so what A/R turbo would you recommend

Thanks kyle
 
A Centrifugal Supercharger makes boost proportional to rpm which is opposite of what you are looking for.

I'm assuming this is for your 200 six with a stock head?
You need a turbocharger with a 47mm compressor inducer and a T3, .64 A/R turbine housing.

One of the main keys is not to overcam your engine.
Keep the .050" duration well under 210 degrees and use a wider 112 degree Lobe Separation angle.
A Schneider 256H cam would be a good recommendation.
 
high boost at low RPM could be a problem with a centrifugal without large drive pulley . I run a fairly stock 250 with a centrifugal Vortech V2 blowing thru a 2Bbl Holley. Recently had to swap to a smaller driven pulley on the SC to enable enough boost at lower RPM, now get @ 10 psi at 4500 rpm. Most SC's are secondary geared to be driven by comparatively high spinning V8's.

With a Buick Riviera derived draw-through Garrett T3/Quadrajet on a previous- 250 , increased boost incrementally to @ 20 PSI with plenty of available power at lower RPM when spooled up - until an oily mist across windshield when pistons ring lands broke off ...

the forced induction projects are like steam engines and fuelie' dragsters -, maximum power is reached just before catastrophic failure ...

hope to see pics of the project


have fun






Vortech V2 specs are @ 680 HP at 20PSI boost at 50,000RPM Impeller speed.

With serpentine 6.125” (5.0 V8) Crank Pulley and 2.5” Supercharger pulley, the two pulley sizes and internal SC step-up gearing yields an IMPELLER rotation speed calculated at @ 22,000 RPM at cruise speed with engine RPM @ 2500RPM.

At typical 250 SIX upper shift point of @ 5,000 RPM the Supercharger impeller speed approaches 45,000 RPM !. Calculating to an Impeller speed @ 750 Revolutions per SECOND.
 
Couple things here, 15+ lbs at 3,000 rpm with stock parts on pump gas will be a disaster. Realistically 10 lbs. at around 3,000rpm is doable. If you are thinking 20 lbs of boost than you need to have the $$$ for rods and Pistons. Low RPM's and high boost destroy rods and pistons without very good control of timing.
Another thing to keep in mind is Turbo's are kinda give and take. example is you want ample boost at low rpm than you most likely will have a turbo that is completely out of the efficiency range at upper rpm's.
A stock 200 stops making power around 3500-3800 rpm but if you turbo that same stock motor it will make power to 5,000 (or so) rpm. For street fun I'd use a small size impeller and a larger size AR exh housing. Add a boost by RPM controller.
Don't forget you'll need a fuel system that can support your max boost plus 7 psi if you are staying carb.
 
Know my setup is different but if you want power. A turbo setup is the way to go. My 300 makes 18psi by 3k rpm and pulls like a freight train. I have a gt35 on my engine and some head work with forged pistons. I admit I'm not that familiar with the 200 capabilities but I think a t3t4 turbo would suit you well.
 
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