I'm getting close to finishing my chevelle and am currently trying to pick out the proper rear end gears and 1st gear ratio that I'll use in either a new Jerico 4-speed or a reworked Richmond 5-speed that Liberty will be offering this winter.

I've been learning quite a bit from Roger Copeland (383Malibu) and Ryan Hotchkins (66 283) who both have cars like mine with a ladder-bar/coil over rear setup and run 10.0 and under.

My setup is as follows:

408 (0.060 over 396), 625 HP NA
Pro-Race fogger (currently jetted at 200 HP)
Ram Aluminum flywheel
McCleod Sintered Iron/sprung hub clutch
Ram adjustable Pressure Plate
Muncie M-21 and Richmond-5 RR (both with Long In-line shifters) To be replace shortly.....
Denny's Aluminum MMC driveshaft with 1350 ends
12 bolt (soon to have 33 spline axles and spool)
3.73 gears (soon to be 4.11 or 4.56???)
CE Ladder-link rear suspension
HAL/QA-1 front and rear coil overs (12 way shocks)
CE W-link locator
CE Anti-roller bar (soon to be installed)
Fuel Cell
Trunk mounted battery
Holley 160 Volumax pump (AN-8 lines)
2 Holley regulators (Volumax for carb, Blue for NOS)
Moroso Cool can
Victor Jr Intake
Holley 950 HP
Crower roller
Jesel shaft rockers
CSI water pump
Mark VIII fan
Front: Monocoque 15x7's with BFG 225-60R15
Rear: Monocoque 15x10's (5.5BS) with BFG DR 325-50R15

Can anyone help me out (or point me in the right direction) with selection of my Starting Line Ratio (SLR)??? Based on talking to Roger and Ryan I have tentatively selected either 4.11 or 4.56 gears based on crossing the finish line at 7500 rpm... If I run the fogger with over 200 HP the 4.11's may be best, but if I run NA then the 4.56's might be best...

Any suggestions on the best way to select my SLR?

If you need more infomration, just let me know.

Thanks guys.

Rich

Rich

Since you are looking at running your engine in two different modes its hard to nail it down. You really will have to pick which method you want and stick to it. If you don't mind changing gears alot you could get a 9" rearend and have two pumpkins with each gear and go from there.

The cool thing about the jerico is that the ratios for each gear is almost limitless. This will help you tune the car for each gear.

Have you decided what ratios you want for each gear. I might be able to help you in that department if youd like.

And I'll do it for real cheap. just ship the vette and we'll call it even stevens haha.

Todd

Are you going to race those tires you listed. What is the rolling radius on those. What i mean by this is actually measure the centerline of wheel to the ground. The tire will deflect when weight is put on it. In other words you may have a 30" tire but your rolling radius maybe 14" instead of 15".

Todd

Todd,

Thanks for the feedback....

I think my primary mood of operation at the track will be using the fogger... So we're looking at 825+ HP....

I'm not sure what tranny (Jerico-4 DR-4, or Liberty's reworked Richmond-5, which they will also be offering with various gear ratios)....

Yes, I could definitely use some help selecting my gears. The more input the better.... My engineering mind works well with lots of numbers and lots of data.... graemlins/clonk.gif

I'm all ears.

Rich

Todd,

I measure the rolling radius tonight.... Need anything else?

Oh, the Corvette is currently in pieces as I started the frame off restoration about 15 years ago and then stopped shortly thereafter... My college took preference, then this chevelle that I've owned since I was 16, and now I'm 40... :eek:

I am seriously considering selling the corvette to help offset the costs of my Chevelle pro-street project which has ben quite expensive!!! graemlins/clonk.gif

Rich

As we have talked before I am in nearly the exact situation you are. I am running a 620 hp or so roller 454 and a 200 shot from a Fogger in a Vette. In light of the fact this is a street car and I am not willing to kill it to get every little e.t. out of it I plan launching on the motor and hitting a 200 shot in 2nd and 3rd for the 1/8 and then 4th in the 1/4. My current 2.77 (1st) and 3.70 rear is a good place to start for the launch. I have a pretty good idea what mph the car should do in the 1/8th and 1/4 so I picked the rpm and gear ratio to correspond. I will then fine tune it if neccasary with tire size. The nice thing about a nitrous motor is the tq is so strong you can be off a little on the gear from optimal and the car will still run the number. If I cross the line between 6500 and 7000 I will consider that close enough. My car weighs a tad over 3200 with me in it and if I can run a 9. anything I will be happy... for a while.

I am also waiting on that new Liberty

www.richmondgear.com (http://www.richmondgear.com) has been halpful to figure mph and rpms. Also if you use their drag racing calculator I have found that if you punch in rwhp it is very accurate to help figure mph, less than 2 mph off for me. The e.t is based on a perfect run, something I have not come close to yet.

69 Rat,

Those rear end and gear calculators at the Richmondgear site were definitely interesting!

The optimium numbers chnage quite a bit when I go form NA to the fogger... It still looks like a 4.11 or 4.56 rear is the way to go, but I'm still out to lunch on my first gear ratio... :confused:

Somewheres between a 3.24 and a 2.95... :confused:
and thats a whole lot of playing field graemlins/clonk.gif

Help!

Rich

Todd,

The rolling radius of the BFG DR 325-50R15's (which I intend to use) measures 14 3/8".

Rich

Rich

I am sorry for not posting earlier. things at work has been hectic to say the least. I will work on it alittle today and get with you sometime today or tonight.

Todd

Todd,

No problem.... I know what its like to be overwhelmed at the office! :eek:

Do you have some software or spreadsheets that your using? Or just lots of experience?

If I'm going with the 4.11's and my tires my Desktop Dragster seems to like a 2.95ish 1st gear with corresponding 2.13, 1.57, 1.23, and 1.0 ratios for 2nd through 5th..... These 2 - 5th gears are supposed to be optimized using the calculator at Richmond Gears website.

Optimum shifting to keep within the power/torque band looks like 7250 - 7000rpm as I row through the gears.... This is based on a spreadsheet that Roger Copeland (383 Malibu) provided this weekend.
This data is also supported by the Desktop software and I'm looking at a 10.0 second car if I can obtain a 1.5ish sec. 60 ft. time. I think I can do this once my setup gets dialed in...

If I add in the HP and Torque capabilities of the fogger I'm in a low 9 second car.... Thats assuming I can get it to hook with the right tires, suspension, and clutch setup... graemlins/thumbsup.gif

Thanks for helping me out here! Its nice to use all these tools before spending 1000's of $$$ on rear gears and a new tranny. I really appreciate it.

Rich

rich

email me at rarichar411@aol.com

I need to ask you some questions.

Todd

I think the biggest challenge your gonna have is the drag radials with the clutch. I don't know of anyone myself who has used both together successfully.

Most of the real fast drag radial runners use a glide to kill the start line ration as well as running something in the neighborhood of 3.73 or so gears.

You have got your hands full to dial in a clutch combo and also to make it work with the tires. I'm pretty certain you'll need a programmable timing computer to knock the power down off the line to give the tires a chance of hooking.

I've had good success thus far with the 325/50 DR's, but I run N/A and am probably only making 525 to 550 flywheel hp (th440 with a 2.48 1st and 4.11 gears out back, 5200 flash 8" converter).

Here's a DR specific board you could ask questions on...

http://members5.boardhost.com/RACING-RADIALS/index.html?1008814994

Todd,

You've got mail....

Todd (10secbu)

Thanks for the information. I am running MSD's programmable/digital-7 box so I can retard in any gear, RPM window, and at NOS activation... Lots of timing to play with.... :D

I'll checkout DR's website tonight. I do like the fit and footprint of my 325's....

Rich