power lacking on low end

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power lacking on low end

Post  frank13 on September 8th 2012, 3:36 pm

Ok been to the track a few times now....

First issue was the car would NOT get past 4900 rpm no matter what.....Come to find the springs were installed wrong....way too little pressure....a few shims later and vialo- 6500 with ease and looking for more.... problem fixed

Now we have a new problem/issue Car is lacking low end power.....takes FOREVER to get to the 4000 rpm. once it hits that, the car pulls with authority.
Been advised to pull the cover and check the timing set to make sure its a pre 71 and not the retarded 72 and above. This seems reasonable to me as the valves may be opening late.

Cam is installed "dot to dot"

cam is a lunati 61605
motor is a 10.75 to one
466
stock crank, forged rods and pistons
Pi heads,
stealth intake
7850 holley carb with perc adjustajets
trnas is t56 cobra clutch

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Re: power lacking on low end

Post  Gary Varney on September 8th 2012, 4:58 pm

I know the feeling, I could write a book on everything my stuff has thrown at me this year. Developed a miss and changed EVERYTHING but the paint color and still had it. Many track rentals and 43 runs later I found a plate in the hood scoop had evidently moved causing the air to pull fuel out through 1 of the high speed air bleeds at high speeds. That was just one of the many issues this season. Fought chasis issues, starter issues, fuel supply issues, transmission issues which I have always had good luck with. The latest is a cracked, yes cracked torque converter case that nearly got me in trouble at 160 mph. Good luck finding your problem!

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Re: power lacking on low end

Post  69F100 on September 8th 2012, 5:06 pm

Frank I will send you pics of the intake tomorrow I keep forgetting to take some for you. Frank put you a automatic in it with a good stall so you leave at 4000.Have you tried leaving at 4000 or will your chassis hold dumping the clutch at 4000 rpms if so try it let it all hang out and hope it all stays together. Twisted Evil
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Re: power lacking on low end

Post  4604X4 on September 8th 2012, 5:10 pm

Is your timing locked or advancing? If advancing, check the advance curve - make sure its working.
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Re: power lacking on low end

Post  frank13 on September 8th 2012, 6:24 pm

so heres my issue....i thought the 460 was supposed to have balls down low.....i am looking for the torque this thing is supposed to have
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Re: power lacking on low end

Post  bbf-falcon on September 8th 2012, 6:32 pm

Gary Varney wrote:I know the feeling, I could write a book on everything my stuff has thrown at me this year. Developed a miss and changed EVERYTHING but the paint color and still had it. Many track rentals and 43 runs later I found a plate in the hood scoop had evidently moved causing the air to pull fuel out through 1 of the high speed air bleeds at high speeds. That was just one of the many issues this season. Fought chasis issues, starter issues, fuel supply issues, transmission issues which I have always had good luck with. The latest is a cracked, yes cracked torque converter case that nearly got me in trouble at 160 mph. Good luck finding your problem!

Sorry to hear this Gary.Sounds like its finally getting around to you. Sounds like some of my issues for the last couple of years w/Falcon.Hell,i've seen you change Tranny's in between rounds at a National event and still win the race. keep at it brother,hope to see you at Norwalk in Oct. Wink

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Re: power lacking on low end

Post  rmcomprandy on September 8th 2012, 7:11 pm

I don't mean to be unsympathetic on this because I do feel bad for your problems.
However, almost every engine I have built within the last ten years has been tuned or at least run on a dyno.
Before then any performance drawback was most always assumed to be an engine problem by the car owner but, now I have proof that it isn't.

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Re: power lacking on low end

Post  frank13 on September 8th 2012, 7:13 pm

here is a video from yb race last weekend.....

I left at 2500rpm drag radials..springs are way too stiff (road race suspension still on car)

after the 2 shift it picks up like a bat out of hell!



car went 113 at 12.73 reaction time was a whooping 1.143LOL sixty was 2.0 1/8 was 8.49 at 88
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Re: power lacking on low end

Post  Curt on September 8th 2012, 11:54 pm

What is the converter flashing at.
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Re: power lacking on low end

Post  cool40 on September 9th 2012, 12:10 am

Curt wrote:What is the converter flashing at.
its a t56..... Smile
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Re: power lacking on low end

Post  Curt on September 9th 2012, 1:04 am

cool40 wrote:
Curt wrote:What is the converter flashing at.
its a t56..... Smile

LOL drunken No wonder it's a dog off the line. Laughing

I was thinking it was a C4 cheers
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Re: power lacking on low end

Post  Mark Miller on September 9th 2012, 2:31 am

Was it spinning at 2,500 rpm if not keep raising the rpm launch till it spins.IMO,2,500 rpm is nowhere near high enough i wouldn't be suprised if it's not bogging.If it's bogging the rpm's are to low to recover.It's a stick shift so you're going to have to drive it like you hate it for it to et good IMO.It's not a automatic with a stall converter to flash into the higher rpm range that you need.

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Re: power lacking on low end

Post  Mark Miller on September 9th 2012, 2:35 am

If it doesn't 60 ft it's not going to et good a 2.00 second 60 ft is not good.My 2011 F-150 Supercab 4X4 with EcoBoost V-6 had a 2.07 60 ft.

Later Mark.

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Re: power lacking on low end

Post  dfree383 on September 9th 2012, 3:57 am

frank13 wrote:so heres my issue....i thought the 460 was supposed to have balls down low.....i am looking for the torque this thing is supposed to have

Did you degree the cam?

DO you know How to tune an engine?

DO you know how to set-up a drag car?

DO you have enough gear in the car?

DO you know how to drive a manual transmission in a drag car?
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Re: power lacking on low end

Post  69F100 on September 9th 2012, 6:51 am

Frank you need to leave at higher rpm was you sleeping on the tree you see that last yellow light come on dump the clucth and go Sleep .Put some heat in them tires gettem sticky it look likr when you got up in the r's it came alive.I agree try adding another 500 rpms each time until you start spinning the tires
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Re: power lacking on low end

Post  cool40 on September 9th 2012, 12:07 pm

the t56 is gona take a dump but you will need to hit it harder to 60'. Smile
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Re: power lacking on low end

Post  frank13 on September 9th 2012, 1:34 pm

t56 is going away....trying to work a deal on a c4 or powerglide trade.
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Re: power lacking on low end

Post  dfree383 on September 9th 2012, 1:48 pm

frank13 wrote:t56 is going away....trying to work a deal on a c4 or powerglide trade.

If your going to drive it on the street use a C6
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Re: power lacking on low end

Post  frank13 on September 9th 2012, 1:49 pm

dfree383 wrote:
frank13 wrote:t56 is going away....trying to work a deal on a c4 or powerglide trade.

If your going to drive it on the street use a C6

why?
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Re: power lacking on low end

Post  dfree383 on September 9th 2012, 1:51 pm

Heavy duty, 3 gears and it will take a serious amount of abuse and not cost an arm and a leg.
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Re: power lacking on low end

Post  bbf-falcon on September 9th 2012, 3:20 pm

I agree,and you'll see your ET pickup also and more consistency.

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Re: power lacking on low end

Post  frank13 on September 9th 2012, 10:22 pm

timing cover off.....cloyes 3130 timing set....post 72 set 8 degrees retarded.....

new timing set being picked up in the am
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Re: power lacking on low end

Post  cool40 on September 9th 2012, 10:25 pm

frank13 wrote:timing cover off.....cloyes 3130 timing set....post 72 set 8 degrees retarded.....

new timing set being picked up in the am
Suspect
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Re: power lacking on low end

Post  IDT-572 on September 9th 2012, 10:41 pm

The post 72 timing set strikes again.................... Twisted Evil Mad
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Re: power lacking on low end

Post  dfree383 on September 9th 2012, 10:44 pm

Some one needs to Learn to degree a cam......... lol! [u]


Last edited by dfree383 on September 10th 2012, 12:02 am; edited 1 time in total
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