How much power does a c6 rob ?
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Senior User
Joined: May 2004
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How much power does a c6 rob ?
I have a 1984 F250 xlt with a rebuilt 466 v8 backed by the c6 auto.
I put an RV cam in...new lifters...bored it from 460 to 466, new pistons, rings, weiand intake, edelbrock 750 cfm carb....freshened the heads up, etc. Basic rebuild.
I've been told, that I should be able to ROAST tires with that engine....but I can't....ever....I'm suspecting the trans?
I put an RV cam in...new lifters...bored it from 460 to 466, new pistons, rings, weiand intake, edelbrock 750 cfm carb....freshened the heads up, etc. Basic rebuild.
I've been told, that I should be able to ROAST tires with that engine....but I can't....ever....I'm suspecting the trans?
Post Fiend
Joined: Dec 2007
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From: Lost
The C6 trans doesn't "rob" any more power than most other trans. They all require a certain amount of power to operate, same as the rearend. Overall, you are looking at around 15-20% power loss in the drivetrain.
Auto trans have a torque converter that actually multiply the torque of the engine, to assist in getting a load moving from a dead stop.
If you have trouble with getting the rear tires to spin, with that combo, I'd be looking into the overall tune of the engine, and determine which rear gear ratio the truck has.
For what it's worth, I have a stock 300 CID I6, C6 trans, and a 2.75 rear gear ratio, and I can break the rear tires loose with it. Considering the tires are 31x10.50-15 BFG all terrains, they may not spin very fast or far, but they will break loose if I try.
Auto trans have a torque converter that actually multiply the torque of the engine, to assist in getting a load moving from a dead stop.
If you have trouble with getting the rear tires to spin, with that combo, I'd be looking into the overall tune of the engine, and determine which rear gear ratio the truck has.
For what it's worth, I have a stock 300 CID I6, C6 trans, and a 2.75 rear gear ratio, and I can break the rear tires loose with it. Considering the tires are 31x10.50-15 BFG all terrains, they may not spin very fast or far, but they will break loose if I try.
Posting Guru
Joined: Jan 2003
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From: Munroe falls, Ohio
2200rpms@50mph is 4.10 gears.
you should have no problem shredding the tires.
Does the trans shift twice, maybe its starting in second gear.
you should have no problem shredding the tires.
Does the trans shift twice, maybe its starting in second gear.
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Fleet Mechanic
Joined: Mar 2005
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From: St Louis
Another consideration is a limited slip rearend makes it rather difficult to get just a chirp out of the tires. Also, low converter stall doesnt help either because the converter doesnt multiply enough torque to over come the gearing.
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Laughing Gas
Joined: Aug 2006
Posts: 1,249
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From: oklahoma
cam may be killin some low end depending on how much duration it has but (rv cam ) should'nt be try setting timing @37degrees total with rpm's around 3000 with vac unpluged if balancer is right and leave it unpluged an try it that way to see if it helps.i set up dizzy with just the lite spring in it so timing comes up faster lol like as soon as the motor starts. 410 gears in a dually we had to pull a 32 ft enclosed would roast all 4 rear tires and bark 2nd. but if you would like there are c6 kits that reduce drag by they say half i've built many of the c6's that way it helps on life of trans a lot. heres so reading for you from another site
http://460ford.com/viewtopic.php?p=6...ghlight=#64906
so good luck hope it helps you out
john
http://460ford.com/viewtopic.php?p=6...ghlight=#64906
so good luck hope it helps you out
john
Senior User
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Originally Posted by 84-250
2200rpms@50mph is 4.10 gears.
you should have no problem shredding the tires.
Does the trans shift twice, maybe its starting in second gear.
you should have no problem shredding the tires.
Does the trans shift twice, maybe its starting in second gear.
Ok, my NP435 has a 1.00:1 4th gear. I have 31x10.50 15's and I run 2200 RPM at 55mph. And I have a 3.50 axle ratio. Did you do a formula to figure in his tires to get that he has a 4.10 axle ratio?
Either way, doing 50mph @ 2200RPM definitely says you have gearing to roast your tires pretty easily. One thing that doesn't help is that, if my research is right, a 2.46 first gear isn't that low. But as others have said, you should be able to spin the tires if you had a bone stock engine.
Other than not being able to burn out, how does your truck run?
Posting Guru
Joined: Jan 2003
Posts: 1,412
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From: Munroe falls, Ohio
IcemanV8: I used randy's ring & pinion website calculator.
LT235/85-16 tires are 31.73" tall
with 3.55 gear @50mph =around 1900 rpms
3.73 gear =2000rpms
4.10=2200rpms
but then the c6 doesnt have a lockup convertor so, the original poster should lift the rear axle and count tire to driveshaft rotations.
LT235/85-16 tires are 31.73" tall
with 3.55 gear @50mph =around 1900 rpms
3.73 gear =2000rpms
4.10=2200rpms
but then the c6 doesnt have a lockup convertor so, the original poster should lift the rear axle and count tire to driveshaft rotations.
Posting Guru
Joined: Jun 2004
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From: Niceville, FL.
My '83 F350 dually with 460, C6 and 4.10 (10,000 lb. GVWR flatbed dump) will chirp the 7.50 X 16 bias ply tires pretty good with no load. You didn't possibly get the cam timing off by 1 tooth during reassembly did you (been there, done that)?