Big Cubes for TT?
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Safety Car
Joined: Apr 2003
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From: Woodbridge Ontario
Big Cubes for TT?
Had a conversation with a fellow Corvette owner, and we were discussing cubes with Twins. We were talking about going with either a 427 or 454ci.
I always gone with the notion that the more you can make on the motor, the better off you are. This way you can make same power with less boost, less lag, and all things being equal, should last longer.
My buddy argued the fact that you can have too much cubes, for example a 454ci with say, a pair of GT35's.
Opinions? Would you go with a 454ci if you could, or stay with a 427 and why?
I always gone with the notion that the more you can make on the motor, the better off you are. This way you can make same power with less boost, less lag, and all things being equal, should last longer.
My buddy argued the fact that you can have too much cubes, for example a 454ci with say, a pair of GT35's.
Opinions? Would you go with a 454ci if you could, or stay with a 427 and why?
Heel & Toe
Joined: Dec 2006
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I would think that with a street car, the TT's would take to long to spool on the bigger cubes. You wouldn't see the full benefit. (Talking about city type driving)
I would vote for the smaller cubes and comparably matched turbo's
I would vote for the smaller cubes and comparably matched turbo's
Thread Starter
Safety Car
Joined: Apr 2003
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From: Woodbridge Ontario
Just the way I see it, could be wrong though.
Instructor
Joined: Aug 2006
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Holding everything else constant, the 454 will have more airflow at a given RPM, and will therefore spool the turbos sooner and faster than the 427.
I can't imagine a properly configured 427 or 454 having any difficulty spooling up GT35s in a hurry. And you're right... any delay in spool is more than compensated by the greater power output from those larger displacement engines at lower RPM.
I can't imagine a properly configured 427 or 454 having any difficulty spooling up GT35s in a hurry. And you're right... any delay in spool is more than compensated by the greater power output from those larger displacement engines at lower RPM.
Safety Car
Joined: Mar 2006
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From: Sarasota Florida
St. Jude Donor '06
I think the Warhawk 481 looks very interesting. Still at 4.125 bore, and still has a good ring pack. The shortblock is only a little more than a good 427.
Thread Starter
Safety Car
Joined: Apr 2003
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From: Woodbridge Ontario
More power out of boost, make the same power of a smaller cube motor at lower boost levels.
It's all good IMO!
Safety Car
Joined: Jul 2004
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From: Valrico Florida
IMO after all the reading I have done anything above a 348ci with turbo's that can flow 63lbs/min or less is overkill for the street.
As for bigger cubes having lag with GT35R's that is just silly. The more cubes you have the cfm requirement for the engine to perform the way it should goes up.
The benefit of bigger cubes is the ability to make more power on pump gas(91/94 octane). I hear people saying all the time you can run less boost and more power on the big cube motors. This is true, but it still depends on both setups. Power under the curve is awesome with a larger motor, but there is such a thing as too much when you dont have the tire to support that power under the curve.
It amazes me people spend so much money on a particular combo and then complain about filling bottles or running C16 every now and then. If you are trying to go fast then you do what needs to be done period.
Also, in this scenario you are limited by the capabilities of the turbos. Whether they are on a 281ci or a 454ci the peak will be very similar.
As for bigger cubes having lag with GT35R's that is just silly. The more cubes you have the cfm requirement for the engine to perform the way it should goes up.
The benefit of bigger cubes is the ability to make more power on pump gas(91/94 octane). I hear people saying all the time you can run less boost and more power on the big cube motors. This is true, but it still depends on both setups. Power under the curve is awesome with a larger motor, but there is such a thing as too much when you dont have the tire to support that power under the curve.
It amazes me people spend so much money on a particular combo and then complain about filling bottles or running C16 every now and then. If you are trying to go fast then you do what needs to be done period.
Also, in this scenario you are limited by the capabilities of the turbos. Whether they are on a 281ci or a 454ci the peak will be very similar.
Safety Car
Joined: Jul 2005
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From: Vancouver WA
More cubes + less boost = less cubes + more boost.
Plus, the bigger bore makes for better breathing heads.
You just need to make sure the turbos are the correct size for your purpose. You can have to options going with a 100 inch bigger motor. 1: same size turbos used on a stock inch motor with a very fast spool up, about the same power with less boost (without overspinning the turbos).
2: Bigger turbos than you would want to run on a stock inch motor for more power output.
Plus, the bigger bore makes for better breathing heads.
You just need to make sure the turbos are the correct size for your purpose. You can have to options going with a 100 inch bigger motor. 1: same size turbos used on a stock inch motor with a very fast spool up, about the same power with less boost (without overspinning the turbos).
2: Bigger turbos than you would want to run on a stock inch motor for more power output.
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Drifting
Joined: Dec 2003
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u gotta decide
if you wanna run low elevens hi tens...go with the cubes...if you wanna run deep tens than boost is the only way to go...I will be running hi
9's next year with a stick...that should be enough for me with my 402 and my paxton Novi...I have all kinds of stuff to do...shocks, heads + cam, pulleys, crank balancer....plus a couple of secrets that I cant tell anybody about....
You gotta decide if you wanna go fast or look pretty 
I dont think your gonna see too many big cube straight motors shooting for 900 rwhp....good luck 
9's next year with a stick...that should be enough for me with my 402 and my paxton Novi...I have all kinds of stuff to do...shocks, heads + cam, pulleys, crank balancer....plus a couple of secrets that I cant tell anybody about....
You gotta decide if you wanna go fast or look pretty I dont think your gonna see too many big cube straight motors shooting for 900 rwhp....good luck
Last edited by HRTBRCR; Sep 20, 2007 at 10:41 AM.
Safety Car
Joined: Mar 2006
Posts: 4,448
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From: Sarasota Florida
St. Jude Donor '06
This was the instigating factor of the discussion. We found the difference between a 427 to a 454 to a 481ci Warhawk SB's were negligible. If you were contemplating a 427ci Warhawk, why not a 454ci?
More power out of boost, make the same power of a smaller cube motor at lower boost levels.
It's all good IMO!
More power out of boost, make the same power of a smaller cube motor at lower boost levels.
It's all good IMO!
Last edited by Gannet; Sep 20, 2007 at 11:51 AM.
Racer
Joined: May 2006
Posts: 449
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From: Little Elm Tx
More cubes + less boost = less cubes + more boost.
Plus, the bigger bore makes for better breathing heads.
You just need to make sure the turbos are the correct size for your purpose. You can have to options going with a 100 inch bigger motor. 1: same size turbos used on a stock inch motor with a very fast spool up, about the same power with less boost (without overspinning the turbos).
2: Bigger turbos than you would want to run on a stock inch motor for more power output.
Plus, the bigger bore makes for better breathing heads.
You just need to make sure the turbos are the correct size for your purpose. You can have to options going with a 100 inch bigger motor. 1: same size turbos used on a stock inch motor with a very fast spool up, about the same power with less boost (without overspinning the turbos).
2: Bigger turbos than you would want to run on a stock inch motor for more power output.
Safety Car
Joined: Apr 2004
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From: Hayward California
I'd only go with a 454 if it made me faster... and since I wouldn't know how to keep an optimally setup 346 planted, let alone a 408, and run it at low boost in the streets, the answer is "not worthy".
Arnel
Arnel
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Safety Car
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From: Woodbridge Ontario
Le Mans Master
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St. Jude Donor '08
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Safety Car
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From: Woodbridge Ontario
Melting Slicks
Joined: Sep 2002
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From: MI
This discussion comes up alot on the Viper boards...488CI motors.GT35's are NOT too big for a 454. Important thing to remember is to size the turbos appropriately for your intended use (i.e. everyday driving, street - race, hi-way rolls, track, etc.) and engine size. There is no simple formula as many would suggest.
