gearing ?

[john858]

i was wondering if i needed to go to 4.56,heres some backround i have a 3200lb 78 malibu with 860 hp 565,180str.cut glide with 4.88,1432 hoosiers, once you guys helped me get the chassis straight the is great,but i think the et is alittle slowin the 1/8. 60' 130 330' 3.87 & 1/8 is 6.04 to 6.05 i justwant to know what you guys thought .thanks john

[itsabird]

what mph are you getting?

[johnracer]

I'd say the 4.88's are about right even for 1/4 mile. 4.56's would be more consistent, but will slow you down unless you're spinning now.....1.30 60' isn't bad for a car that heavy :D

Johnny

[john858]

sorry :oops: mph is 113

[dparker]

If your racing 1/8 mile stay with the 4.88s. At 113 mph your only running around 5700 rpms. If you race 1/4 very often I'd probably change to 4.56s, if nothing else to keep from taching to many rpms on the big end. Your 1/4 mile mph should be around 140mph. Your car should set the chassis and hook better with the 4.88s. If you never run 1/4 mile you might try a set of 5.14s, they would really make that Malibu leave hard and probably get you in the 5s. A set of 5.14s would probably have you turning around 6300 rpms in the 1/8. Overall the 4.88s are a pretty good gear for you.

[Tod74]

32 X 14 WITH 5.14 GEARS I am about 6800 at the eighth at 110 mph

[itsabird]

numbers are fairly close with that gear, i agree with the other guys, if you only run 1/8 a 5.14 could be better, and may drop your 60' time 3 or 4 hun.

[bjuice]

..You did not mention the most important factor here..What height tire you running and most important what is the roll out?

Next don't be fooled by MPH when it comes to trying to get your gear right..a spinning car will MPH more then a hooked car.
you need to concentrate on what the car is turning in high gear thru the traps.

also mark your tires and have some video your launch focusing on back tires to see how much spin you got here....i like the video cause i don't trust what other people see or think they see. 8)

Brian

[john858]

thanks guy i just thought it might be alittle slow from the 330' to the 1/8 but from what you guys are saying its about right. brian 14/32 hoosiers think the rollout was 105.thanks,john

[bjuice]

then she is a little taller 14/32 tire...you can get a 100 roll out in the same 14x32 tire which would turn the rpms on up for you if need be...could be an option when you needing new slicks..instead of gear changing

what are you turning in high gear thru traps ?

i run a 101 rollout with a 17x33 tire.....very short 33 tire...

[Tod74]

HE said he had 14x 32 hoosiers.

[dparker]

Try this rpm/mph calculator. In your case type in the mph, gear, and tire size then click the mph its pretty close. These calculators are a good tool when your thicking about gear changes.
What the tire says on the side (14x32) means almost nothing. It just gives you a ballpark figure.
To get a true tire size, take your roll out and divide it by 3.1416 and that will give you a exact tire height. Your 105 rollout, 105/3.1416=33.42

http://golenengineservice.com/calc/calcrpm.htm

http://www.1bad69.com/calc.htm

[Tod74]

Wow that calculator isn't even close for mine...does that mean the converter is too loose? I have 32 x14 goodyears and the rollout I think is 102. Last time out I was right around 67-6800 at the eighth and my mph was 110. I have a 5.14 rear gear.

[dparker]

Sounds like your converter is not locking completely up. These equations are usually within a couple of hundred RPMs. Supposedly your converter never fully locks up. But should be 95% locked up on the big end.

[Tod74]

Sounds like your converter is not locking completely up. These equations are usually within a couple of hundred RPMs. Supposedly your converter never fully locks up. But should be 95% locked up on the big end.

Converter was built for a smaller motor that I had previously...it had very few runs and I figured I would just try it...It is a COAN 8" and he told me the same thing...just try it and let him know how it did and go from there. It was built for a 454 this is a 540 makes a lot more torque. I have never tested how high the converter goes with this engine but I did with the smaller one. It went 5400 behind the 454.

[bjuice]

Try this rpm/mph calculator. In your case type in the mph, gear, and tire size then click the mph its pretty close. These calculators are a good tool when your thicking about gear changes.
What the tire says on the side (14x32) means almost nothing. It just gives you a ballpark figure.
To get a true tire size, take your roll out and divide it by 3.1416 and that will give you a exact tire height. Your 105 rollout, 105/3.1416=33.42

http://golenengineservice.com/calc/calcrpm.htm

http://www.1bad69.com/calc.htm


:wink: ...there ya go !

my 17x33's with a 101 roll out is actually only 32 inches tall

[john858]

Brian,what kind of slicks do you run? Tod i did the same thing just tried the converter i had & ended up having one built. warning thought when you get one that works it shows all your other problems :lol: of coarse i went from sbc ,176 glide to alittle bigger combo :lol: .thanks again guys your the best.john

[bjuice]

M/T
Jegs Part# 672-3088

[Tod74]

Brian,what kind of slicks do you run? Tod i did the same thing just tried the converter i had & ended up having one built. warning thought when you get one that works it shows all your other problems :lol: of coarse i went from sbc ,176 glide to alittle bigger combo :lol: .thanks again guys your the best.john

I'll have one built just as soon as I destroy this one. :lol: I paid $900 so I'm using it. I already asked COAN about reworking it to this combo he said no dice...said try it and see but if it was too loose I'd have to go with a 9"

[dparker]

Dang Todd this is Racingjunk.com sell yours and get a 9" that you want. Hect your car might scare you with the right converter.

[Tod74]

Dang Todd this is Racingjunk.com sell yours and get a 9" that you want. Hect your car might scare you with the right converter.

It scared me with the wrong one!! :lol:

I don't know for sure it is "wrong" like I said I gave COAN the engine specs and he said it was borderline, just to try it and see...I have only 4 passes on it with this motor ...launches hard but too many other bugs so far to tell if it will need to go.

[dparker]

Well you always have the Christmas list to give to the wifey.

[bjuice]

Hey Tod them Bugs ya speaking of ain't the QUAMY'S sneaking up in that gut is it ?..lol. :D
All jokes aside its a Good thing to be A little spooked..you'll live longer that way !

i get them everytime. no matter if i am in a 6 second car or a potential 4 second car..for some reason it all goes away when i let go of the button...wonder why :?: :? :?

[BEAST477]

Hey Brian, is that what they call first round jitters? First round seems to be the hardest.

[john858]

what kind of rpm do you think i would turn in the 1/4 with 5.14's, i run mostly 1/8 but 1/4 3 or 4 times a year. tod it took me a good solid month to work the bugs out ( with all your guys help ) then it started to get fun & everything closed :cry:
all ready for next year unless someone buys the car this winter.then i'll just have to build something else :wink:
plus i have to find one or two jr's for my nephew & daughter

[bjuice]

john u probably know this..anyhow when you store the car for the winter place it on jack stands..if i have see this question once i have seen it 100 times..."It was running good and straight when i parked it for the winter,brought it out 1st time and its all to hell"

all this equaled wiped out springs.

[BillyShope]

...take your roll out and divide it by 3.1416 and that will give you a exact tire height.

A more convenient number is obtained by dividing the rollout into the number of inches in a mile. This gives you wheel revolutions per mile.

Then, draw a long horizontal line and start inserting the things you know, with the goal of canceling values that appear both above and below the line. You have N wheel revolutions per mile, S miles per hour, and G axle ratio (ratio of engine revolutions to wheel revolutions). So, when you multiply these out, the "mile" of N cancels the "mile" of S and the "wheel revolutions" of N cancels the "wheel revolutions" of G, leaving engine revolutions per hour. Divide by 60 and you have engine rpms. (Or, more rigorously, divide by the number of minutes in an hour, which cancels out the hours. Fewer mistakes are made when the problem is completely set up and the units have been reduced to those desired BEFORE picking up the calculator.)

[dparker]

...take your roll out and divide it by 3.1416 and that will give you a exact tire height.

A more convenient number is obtained by dividing the rollout into the number of inches in a mile. This gives you wheel revolutions per mile.

Then, draw a long horizontal line and start inserting the things you know, with the goal of canceling values that appear both above and below the line. You have N wheel revolutions per mile, S miles per hour, and G axle ratio (ratio of engine revolutions to wheel revolutions). So, when you multiply these out, the "mile" of N cancels the "mile" of S and the "wheel revolutions" of N cancels the "wheel revolutions" of G, leaving engine revolutions per hour. Divide by 60 and you have engine rpms. (Or, more rigorously, divide by the number of minutes in an hour, which cancels out the hours. Fewer mistakes are made when the problem is completely set up and the units have been reduced to those desired BEFORE picking up the calculator.)

I sorry but there's no way that's more convenient way to get the diameter of a circle. The Greeks derived this equation thousands of years ago. And I have yet to see a simpler version.
Pi R squared will get you the area. BUT WHY!!!
Diameter of a circle = Circumference divided by Pi (3.14159265).

And there is no more convenient way to derive the diameter of a circle. Even Albert Einstein used the Greeks version of how to find the diameter of a circle.

[Tod74]

Hey Tod them Bugs ya speaking of ain't the QUAMY'S sneaking up in that gut is it ?..lol. :D
All jokes aside its a Good thing to be A little spooked..you'll live longer that way !

i get them everytime. no matter if i am in a 6 second car or a potential 4 second car..for some reason it all goes away when i let go of the button...wonder why :?: :? :?

maybe scared wasn't the best word for it.....but it sure surprised me...amazing what 80 more cubic inches will do. :D

[john858]

talk about difference i went from 388 to 565 wow :shock:

[bjuice]

Hey Tod them Bugs ya speaking of ain't the QUAMY'S sneaking up in that gut is it ?..lol. :D
All jokes aside its a Good thing to be A little spooked..you'll live longer that way !

i get them everytime. no matter if i am in a 6 second car or a potential 4 second car..for some reason it all goes away when i let go of the button...wonder why :?: :? :?

maybe scared wasn't the best word for it.....but it sure surprised me...amazing what 80 more cubic inches will do. :D

LMAO...Hey i have no issues admitting it. My Old 63 vette SKEERED the CHIT out of me. :shock: ...and if anyone wants to laugh or sneeker thats Fine with me i will laugh with them :D ...i would like to see them get in a 2200lbs car w/driver with a 632ci with over 1200hp/1,000 TQ and bring it up to 5000rpm and matted to the floor on the two step and let go of the button....... :shock: :shock: yeeeeeahhh Boy call it Skeered,Surprised,a Rush, Respect..etc... or whatever you want to call it...Its all the same..you just CHIT YOUR PANTS....LMAO

[BEAST477]

Man Brian, i'll bet it was one heck of a ride and one you will never forget. That Vette sure was sweet though. I'm lookin' forward to trying out my new combo this spring.