Carb vs FI dyno numbers
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Racer
Joined: Sep 2000
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From: Amarillo Tx
Carb vs FI dyno numbers
Just had my L98 stroked to 383, stock 113 heads heavily ported, LPE 219 cam, forged pistons, Scat crank. There isn't a local rear wheel dyno where I live and no one locally has facilities to dyno an FI car. My engine builder dyno'd my engine using a Holley carb and edelbrock single plane manifold. Peak CHP was 402.6 at 4600 and peak torque was 482.5 at 4100. Engine builder advised I should see more hp with my Superram above 4600. Carb BSFC numbers were rich above 4800rpm. Does an engine with a carb dyno the same as an engine with FI? Worse or better?TIA Tom 
Racer
Joined: Jul 2001
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From: Los Gatos, CA
Low speed and mid-range are typically much better with the superram and FI. You have the longer runners and better fuel distribution at lower speeds. At extreme top end usually the shorter runners of a single plane/carb set-up will make a bit more hp if you are comparing to a superram. The SR's work great on the street and road racing - I have one myself.
Good luck
Good luck
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Man that's a weird tq curve. Peaked Hp at 4600 rpm with a carb and a single plane? And peaked TQ at 4100 rpm??
Definitely strong TQ numbers, that's what the 219 cam is good at, but that sure looks like a tight rpm spread. I usually like to see 1500 rpm spread to get a real good pulling ride.
But I know lots of killer superram cars go awful fast with low rpms and short shifting, I just wouldn't expect to see that with ported heads and a single plane.
JIM
Definitely strong TQ numbers, that's what the 219 cam is good at, but that sure looks like a tight rpm spread. I usually like to see 1500 rpm spread to get a real good pulling ride.
But I know lots of killer superram cars go awful fast with low rpms and short shifting, I just wouldn't expect to see that with ported heads and a single plane.
JIM
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Originally Posted by Thomas454
Does an engine with a carb dyno the same as an engine with FI? Worse or better?TIA Tom
That said the L-98 TPI system was matched with valve timing to provide a very strong mid range torque peak, but at the expense of top end power, so, for example, a single plane manifold with a big carb will make more top end power, but with much less low end and peak midrange torque.
A typical 180 degree manifold and a modest sized carb will generate a torque curve more similar to the TPI system, but will probably make more top end power, with less peak torque. The long TPI manifold runners help create that high midrange torque, but they choke the top end.
It's all in the details.
Duke
Thread Starter
Racer
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From: Amarillo Tx
weird torque curve
Originally Posted by 427Hotrod
Man that's a weird tq curve. Peaked Hp at 4600 rpm with a carb and a single plane? And peaked TQ at 4100 rpm??
Definitely strong TQ numbers, that's what the 219 cam is good at, but that sure looks like a tight rpm spread. I usually like to see 1500 rpm spread to get a real good pulling ride.
But I know lots of killer superram cars go awful fast with low rpms and short shifting, I just wouldn't expect to see that with ported heads and a single plane.
JIM
Definitely strong TQ numbers, that's what the 219 cam is good at, but that sure looks like a tight rpm spread. I usually like to see 1500 rpm spread to get a real good pulling ride.
But I know lots of killer superram cars go awful fast with low rpms and short shifting, I just wouldn't expect to see that with ported heads and a single plane.
JIM
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