Trap RPM WITH 4.30 GEARS QUESTION.

[RT K_line]

Anyone running a 440 with 430 gears and 28, 29 or 30 inch tires? I need new tires and wanted to run the 430 gear ratio so I thought I would ask the racers here what their rpms are thru the traps with each of these tire sizes. Looking to optimize my combo and trap at 6300 to 6500. Maybe there is a formula to figure it out somewhere too. Thanks in advance for your help.

 

[Tex013]

Formula on wallace racing site .
With 30" should be in your rpm range
If rag slick may pull down rpm a little due to growth

Tex

 

[dvw]

You are missing one critical part of the equation, what MPH? My street car goes thru at 7000 /123 using a 28.5"/4.30 Race car goes thru at 7000/147 using a 31"/4.10. Huge speed difference. Figure roughly 7.5% slip in your equation an it'll be within 100-200 RPM.
Doug

 

[Budnicks]

here's another fun one to play with

http://vexer.com/automotive-tools/speed-rpm-calculator

what if #'s
with auto you can adjust TQ efficiency, I use like 85% & use D for high gear
you can change the gear ratios too, it has basic ratios,
but you can click on the 4.10 etc. put the #'s your running in
you can change the tire size move the scale up & down,
a 325/55/15 for like a 29.9" or a 315/60/15 for a 29" etc. etc. etc.
you adjust the top slide "Throttle" bar %'s until or to your desired RPM
on the left side tach for the specific gear/final RPM etc.

have fun

 

[Mike67]

http://www.advanced-ev.com/Calculators/TireSize/
and another.

I thought you were building more of a street bruiser???

 

[Mike Gaines]

I have a 4.30 Dana with 28" tall MT ET Streets (88" Circumference). I go thru the traps at 6800 which nets me 126.4 to 126.7 MPH. I shift 1-2 and 2-3 both at 6000.
Interesting Note: My typical MPH was 124.7 to 125.8 (many runs recorded) and 6500 thru the traps with my OLD Headers which were 1 7/8 Hooker Super comps with 3" Collectors. In preparing to upgrade my INDY SEZ head from Standard Port to Max Wedge Port plus having them ported to flow about 355CFM (from the OOTB of 290CFM) I went ahead and bought and installed my new headers which are Doug's D452's which are 2" tubes and 3 1/2 collectors. With no other changes except the new header size my car picked up thru the traps from 6500rpm to 6800rpm and equates from an average of 125mph to an average of almost 127mph.

 

[bobtile]

Hey Mike,
Did you ever try shifting any higher than 6000?
Im shifting mine at 6600 and hitting the traps at 6800.
Thats what my setup likes best.
Just curious.

Anyway, I have 4.56 gears with 31 inch tires. As stated, 6800 through the traps.

 

[HEMI-ITIS]

I go through the stripe at 145 with a 4:10 gear and 30 inch tire.

 

[SUPERSTOCKRACER]

Here's a double scenario on 2 cars with same tires and gears.
M/T 31 x 10.5W

My 65 light blue dodge coronet. 4.30 gears & M/T 31 x 10.5W goes thru the traps at 7400 rpms at 155.12 605 ci hemi

My 65 Plymouth Belvedere same gears and tires goes through the traps at 7000 at 150.22 605 ci hemi also

Both have 8" converters. So your results will vary.

 

[Mike Gaines]

Hey Mike,
Did you ever try shifting any higher than 6000?
Im shifting mine at 6600 and hitting the traps at 6800.
Thats what my setup likes best.
Just curious.

Anyway, I have 4.56 gears with 31 inch tires. As stated, 6800 through the traps.

On the engine dyno my motor made theost HP at 6000...so I shift at 6000...input on that would be helpful
...thanks, Mike

 

[SUPERSTOCKRACER]

On the engine dyno my motor made theost HP at 6000...so I shift at 6000...input on that would be helpful
...thanks, Mike

Mine made the same too Mike. I shift at 6000 too. I found overshifting slowed me down a bit and didn't pick up any at all. I found shortshifting with these little 500 ci motors don't like much more than 6000 rpms.

 

[HEMI-ITIS]

What was your peak torque?

 

[383man]

I use 4.30's with the hoosier 30 x 9 radial slick. I do run the full exh and I use a Dynamic street/strip 9.5 converter. I also run the Indy dual plane intake since its a street car and the Holley 850 DP. I usually go through the traps about 63 to 6400. And I shift around 6200. Also when cruisin on the highway I turn about 3200 rpm at 60 mph. Ron

 

[RT K_line]

http://www.advanced-ev.com/Calculators/TireSize/
and another.
Yes Mike, I do run mostly on the street but built the engine with 4.30s as the end result in mind and there is a set for sale here.
I thought you were building more of a street bruiser???

 

[RT K_line]

I've played around with the Wallace racing site and figured that 4.10 gears will suit me better since I still drive 40 minutes to the track and back. So I'll be looking around for some. Thanks for everyone's input.

 

[Mike Gaines]

What was your peak torque?

590 Torque @ 5900RPM

 

[bobtile]

On the engine dyno my motor made theost HP at 6000...so I shift at 6000...input on that would be helpful
...thanks, Mike

Ive heard that shifting either side of peak power is best.
I guess it depends on your complete setup.
Some people shift 200 rpm over peak hp so after the shift you are at peak.
Thats why i have been playing with my shift point.
My motor makes peak hp at 6800 rpm. So far, best results have been shifting at 6600.

 

[cudatom]

Anyone running a 440 with 430 gears and 28, 29 or 30 inch tires? I need new tires and wanted to run the 430 gear ratio so I thought I would ask the racers here what their rpms are thru the traps with each of these tire sizes. Looking to optimize my combo and trap at 6300 to 6500. Maybe there is a formula to figure it out somewhere too. Thanks in advance for your help.

When I was running my Cuda I ran Phoenix 29x11.5w(the tires were right at 30.5"). Car ran low to mid teens at almost 130. Shifted at 6300 and crossed the stripe at the same. Can't remember what the convertor stall was. I'm getting old and that was 10yrs ago. I ran a PTC convertor.

 

[SUPERSTOCKRACER]

I just checked my Racepak to carefully check all my Air Fuel Ratios.
With a 31 x 10.5W with 4.30 Strange Pro Gears and a 5900 8" converter, I crossed the traps at 7402 RPM's