Vortec swap Dyno
Thread Starter
Instructor
Joined: Jan 2007
Posts: 233
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From: Simpsonville SC
Vortec swap Dyno
I took my vette to a local speed shop that was having a dyno day to see how my numbers look since my recent Vortec head swap. I made 2 runs including A/F measurements. I suspected I was a bit rich and I was. So I have some A/F tuning to do and some high RPM belt squeal to work on. I don’t think the numbers are too bad for my first project like this. I’m running an L-82 w/Vortec heads, ~10.1 compression Edelbrock Performer intake, Comp Magnum 270 cam and duels with stock exhaust manifolds.
1st run 275hp and 320tq
http://www.youtube.com/watch?v=R4feX15N9-E
2nd run 278hp and 320tq
http://www.youtube.com/watch?v=c2cbHZRMHnE
1st run 275hp and 320tq
http://www.youtube.com/watch?v=R4feX15N9-E
2nd run 278hp and 320tq
http://www.youtube.com/watch?v=c2cbHZRMHnE
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Joined: Apr 2000
Posts: 17,676
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Change the intake to a RPM Air Gap for another 10-15 HP. I got about the same HP/Tq as you did with this manifold and Sportsman II heads. I got around 285RWHP if I remember correctly with same cam and compression ration.
You are making good power, as for flywheel HP it is over 350HP
You are making good power, as for flywheel HP it is over 350HP
Race Director
Joined: Apr 2000
Posts: 17,676
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
My C3 loses roughly 22 % from engine dyno to chassis dyno
I know this because I have done it. Same goes for you, you can't measures net hp very well the only comparison you can make is your motor on an engine dyno ( gross HP ) and in the Vette on chassis dyno ( wheel HP ) .
The guy who gave you the HP numbers would be talking about Net HP numbers as in a C5 where you would have the Net HP from GM and then you put it on a chassis dyno. They have good tight drivetrains and only lose 12-15% max from Net Hp.
I have seen many ZZ4's ( 350 HP Gross ) on a chassis dyno they range 240-265RWHP
I know this because I have done it. Same goes for you, you can't measures net hp very well the only comparison you can make is your motor on an engine dyno ( gross HP ) and in the Vette on chassis dyno ( wheel HP ) .
The guy who gave you the HP numbers would be talking about Net HP numbers as in a C5 where you would have the Net HP from GM and then you put it on a chassis dyno. They have good tight drivetrains and only lose 12-15% max from Net Hp.
I have seen many ZZ4's ( 350 HP Gross ) on a chassis dyno they range 240-265RWHP
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Pro
Joined: Dec 2008
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From: Frisco TX
My C3 loses roughly 22 % from engine dyno to chassis dyno
I know this because I have done it. Same goes for you, you can't measures net hp very well the only comparison you can make is your motor on an engine dyno ( gross HP ) and in the Vette on chassis dyno ( wheel HP ) .
The guy who gave you the HP numbers would be talking about Net HP numbers as in a C5 where you would have the Net HP from GM and then you put it on a chassis dyno. They have good tight drivetrains and only lose 12-15% max from Net Hp.
I have seen many ZZ4's ( 350 HP Gross ) on a chassis dyno they range 240-265RWHP
I know this because I have done it. Same goes for you, you can't measures net hp very well the only comparison you can make is your motor on an engine dyno ( gross HP ) and in the Vette on chassis dyno ( wheel HP ) .
The guy who gave you the HP numbers would be talking about Net HP numbers as in a C5 where you would have the Net HP from GM and then you put it on a chassis dyno. They have good tight drivetrains and only lose 12-15% max from Net Hp.
I have seen many ZZ4's ( 350 HP Gross ) on a chassis dyno they range 240-265RWHP
not disputing your info but 22% is surprising
do you find much variation between auto vs 4 speed?
Thread Starter
Instructor
Joined: Jan 2007
Posts: 233
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From: Simpsonville SC
Drifting
Joined: Apr 2007
Posts: 1,892
Likes: 3
From: Springfield Illinois
Not trying to rain on anyones parade here, but you can not calculate drivetrain loss as a percentage... My explanation:
Example:
350ci. - 350 HP X .20 = 70 HP loss
572ci. - 700 HP X .20 = 140 HP loss
Why would a 572 lose twice the amount of HP than a 350ci? You only lose a fixed number of HP from your flywheel to your wheels...
Example:
350ci. - 350 HP X .20 = 70 HP loss
572ci. - 700 HP X .20 = 140 HP loss
Why would a 572 lose twice the amount of HP than a 350ci? You only lose a fixed number of HP from your flywheel to your wheels...
Thread Starter
Instructor
Joined: Jan 2007
Posts: 233
Likes: 41
From: Simpsonville SC
Race Director
Joined: May 2005
Posts: 10,674
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From: Millington Illinois
St. Jude Donor '08-'09
Not trying to rain on anyones parade here, but you can not calculate drivetrain loss as a percentage... My explanation:
Example:
350ci. - 350 HP X .20 = 70 HP loss
572ci. - 700 HP X .20 = 140 HP loss
Why would a 572 lose twice the amount of HP than a 350ci? You only lose a fixed number of HP from your flywheel to your wheels...
Example:
350ci. - 350 HP X .20 = 70 HP loss
572ci. - 700 HP X .20 = 140 HP loss
Why would a 572 lose twice the amount of HP than a 350ci? You only lose a fixed number of HP from your flywheel to your wheels...