Setting up car for both low speed, and High Speed

Transmission to Rear-end

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predator
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Setting up car for both low speed, and High Speed

Post by predator » Sun Apr 03, 2016 10:33 am

Right Now my Car has a 14-1 440, Torque-flight, Gear-Vendors over-Drive, and 4:88's in the rear. I know how deep Gears are so much fun! I had a Big-Block 56 Chevy with a Muncie. That car also had deep gears. It had 5:13 gears in the rear.

My Road-Runner though, I have my asspirations set on being able to take the Car up to Nevada, and run the Silver-State Road-Race. I want, no I Need the Car to have optimal Gearing for both low-speed's, read under 100 MPH. And I want optimal gearing for High Speed driving. High-spedd being over 200 Mph. So I'm thinking about running a Tremec 6-Speed along with a much talleer Rear-ends gear.

Does anyone out there building a Car that will be able to run both in the lower speeds, and the higher speed range?

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Re: Setting up car for both low speed, and High Speed

Post by PackardV8 » Sun Apr 03, 2016 1:23 pm

That's why the Viper has always had the 6-speed with a .50 top gear. And yes, the deep rear gears run 200 MPH make for high tooth surface speeds, lube temp buildup and high driveshaft rotational speeds - all very bad.
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Re: Setting up car for both low speed, and High Speed

Post by predator » Sun Apr 03, 2016 1:50 pm

My current thoughts regarding my Drive-Line sorted out is that maybe, hopefully Just-Maybe my car would do well with my Running say a tall Rear-end gear. A gear down around a 3:0? then to run a Six-Speed. That way I think I would have pretty good gearing. By good gearing, I mean both low speed, and High-Speed driving.

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Re: Setting up car for both low speed, and High Speed

Post by Brian P » Sun Apr 03, 2016 5:03 pm

Previous thread on this which kind of ended without resolution

viewtopic.php?f=19&t=44511

There is no escaping the math, but the math requires some basic facts to be known.

What is the outside diameter of your drive tires?

What RPM does your engine make peak power at? What RPM is rev limit?

The Viper indeed uses a 6-speed with a very tall 6th (0.50) and a 3.07 final drive ratio; the engine also doesn't rev particularly high. It has P335/35-17 rear tires which have a theoretical rolling diameter (outside diameter) of 26.2 inches and that means 769 revs per mile (the spec sheet that I have suggests 811 revs per mile but the numbers don't jibe). The engine will do 769 x 0.50 x 3.07 = 1180 revs per mile. I guarantee that this setup is a gas-guzzler-tax-minimization strategy and it will not pull top speed in this gear!

On the other hand, 5th is 0.74 and re-crunching the numbers gives 769 x 0.74 x 3.07 = 1747 revs per mile. Now, 180 mph, which is three miles per minute (in the ballpark of top speed for this car) happens at 5241 rpm and that is quite plausible.

Gotta crunch the numbers, gotta get some data with numbers to crunch!

Bear in mind that the Viper has a pretty short drive shaft, so the critical speed should not be a concern, and with IRS and thus having the differential fixed to the chassis, the driveshaft doesn't move around and there's no issue with axle wrap.

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Re: Setting up car for both low speed, and High Speed

Post by predator » Sun Apr 03, 2016 10:05 pm

Please Forgive me for no including some very important things that need to be Considered. I have not settled on my rolling stock. With my Car having the Magnum Force Rack and pinion steering. The Car has Wilwood Disc Brakes. These Brake will require that I run at least a 17" Wheel. If not a 18" wheel.


Right now I will initially run the car with the Rear-End in the Car, Deep Gears and all. In the near distant future I might possibly fabricate to install a Heidts rear suspension.

Doing this car truly is a learning experience. I take one Baby Step after the other.

See Ya: Chris McKeon 925-4971059

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Re: Setting up car for both low speed, and High Speed

Post by ChevyEFI » Wed Apr 06, 2016 12:10 am

I can't speak for race tires for top end, but go for wheels that have the most tire options. In street tires for passenger cars, options in 18" are as common now as 15" were 20 years ago. You might find 18" to be the sweet spot for your build and tire availability too.

0.50 6th was not about top end. Vipers don't use it to top out, and neither did the GM platforms with it. You already saw some options of 5-6 ratios in the last thread.

And I already stated last thread, taller trans. gear and shorter diff. gear is foolish for driveline speed. Autobahn friendly cars are built with a top gear in the 0.80 range commonly, for good reason!

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Re: Setting up car for both low speed, and High Speed

Post by predator » Wed Apr 06, 2016 1:42 am

Guys thanks for your Post's. Here is a general over-all view of what I plan on doing with my Car. I will get the Equal length Merge collector Header's fabricated. I will sort out the Cars Fuel, and electrical system. I will play with the car at our local Drag-Strip that being Sears Point Race-Way.


Most likely as Time allows. Money I have allocated to my Car is adequate. I will proceed on developing my Ride. Yes my car very well might wend up with it's power being delivered to it's rear-end via a 6 Speed. The Rear end very well might be a Tremec I-R-S rear suspension. I also yghink my wheels will end up being 18" Diameter.

You know, i can not wait till I am able to have the Car complete. The Day I can fire the Engine with the That 14 to 1 440 in the Car. That Day will be a Very Fun Day!

Can you say Lights, camera, Violence.

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Re: Setting up car for both low speed, and High Speed

Post by MadBill » Wed Apr 06, 2016 9:32 pm

predator wrote:Please Forgive me for no including some very important things that need to be Considered. I have not settled on my rolling stock. With my Car having the Magnum Force Rack and pinion steering. The Car has Wilwood Disc Brakes. These Brake will require that I run at least a 17" Wheel. If not a 18" wheel.


Right now I will initially run the car with the Rear-End in the Car, Deep Gears and all. In the near distant future I might possibly fabricate to install a Heidts rear suspension.

Doing this car truly is a learning experience. I take one Baby Step after the other.

See Ya: Chris McKeon 925-4971059
Just remember that critical RPM thing. 180 MPH with 4.88:1 gears and Viper-size tires would give ~ 11,250 driveshaft RPM... :shock:
Felix, qui potuit rerum cognscere causas.

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Re: Setting up car for both low speed, and High Speed

Post by predator » Thu Apr 07, 2016 12:31 am

o-K. O-K, I am very much connsish to the reality of excessive Drive-Shaft speed. My first thought regarding having my Car being able to exceed 200 M-P-H was I considered running a second Gear-Vendors over-Drive along with Deep rear-end Gears. But the mere thought of my car having Drive-Shaft Failure at Two Hundred plus, this quite Frankly freaked me out!

I believe my Car will get going pretty much the way it is right now. That being a 440, a Torque-Flight. a Gear-Vendors Over-Drive, and 4.88's in the But. The car should be fun to drive. I can take the Car to the Grocery Store. I can play with it at Sears Point Race-Way. running the 1/4 mile. It should be fun.

I can do research into installing a I-R-S rear-end that has taller gears, and possibly a 6 Speed. Then it very well might be the case that Look-Out Silver State Race Way, here come's one Fast Bird!

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Re: Setting up car for both low speed, and High Speed

Post by pdq67 » Thu Apr 07, 2016 9:53 pm

Might look into "Big Red 1" 1969 Camaro, the Silver State Classic winner years ago.

Here is just one link about it!

http://www.streetlegaltv.com/features/t ... ole-story/

The Legendary Big Red Camaro - The Whole Story - Street ...

Jun 4, 2012 - The original Big Red had both the body and chassis of a stock '69 Camaro. ... one that would beat any road-worthy production car in existence.

I would dearly love to turn my '67 350SS/RS car into something like it EXCEPT for cutting it up..

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Re: Setting up car for both low speed, and High Speed

Post by predator » Fri Apr 08, 2016 1:18 am

I have no problem cutting into my Bird in the hopefully near Future to install a I-R-S rear-End. Heck, I have already done some Major Weld-in items to the Car. Such as Sub-Frame connectors, Chrome-Molly Roll-Cage.

Guys: You know this Building of my B-Body, to run really Fast. THinking about this Car of mine makes think back to When my Friend, Most likely the only Formula one world champion I will ever come to as far as being on a first name Basis with. Well being that Phil was the only person who I knew of who had spent time racing Cars above 200 Miles an hour. I asked Phil "Just how is it to drive a Car at 200 Miles an hour? Phil responded to my query by saying: "Chris, you adapt to the speed. You learn to anticipate things sooner. You would do well at Speed, you'd Love it.

I hope to get my Car finished. For, I want to go fast, I want to go Fast Safely.

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Re: Setting up car for both low speed, and High Speed

Post by Brian P » Fri Apr 08, 2016 4:49 pm

Before you go the IRS route, just bear in mind that NASCAR uses a solid axle rear end. Granted, they're not using leaf springs. If all you are interested in is high speed in basically straight lines, I wouldn't consider IRS to be a critical requirement. A linkage-located axle using coil springs won't have significant axle wind-up issues, either.

If you want it to go around corners on bumpy surfaces, that's another matter.

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Re: Setting up car for both low speed, and High Speed

Post by miniv8 » Sat Apr 09, 2016 9:41 am

Look into adjusting your starting line ratio by lowering your first gear. 2.77:1 instead of the stock 2.45:1 .
Your pull off the line will always be limited by the rear brakes, needing bigger wheels and shorter sidewall.

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Re: Setting up car for both low speed, and High Speed

Post by autogear » Mon Apr 11, 2016 2:00 pm

If you shift into 5th under full power in a T56; theres a solid chance that eventually its going to hemorrhage parts of gears.

I might also mention that the viper T56 still uses the GM F-car double and single cone synchronizers for 1-4. Its only real blessing is the larger output and Mopar specific input.

I would seriously talk to one of the 6-speed specialists about building you a custom gearbox that uses the GTO/Corvette double and triple cone synchros or skipping that entirely and going to a TR6060 which has wider gears and uses a Getrag-style synchro system.
Dave Guffey at RPM Transmissions in Indiana is a great place to start
I'd also mention:
RKT56
D&D Performance
Hanlon Motorsports

There are certainly others, but these are the ones Im most familiar with. I might also consider a single OD and a numerically deeper 1st gear and numerically lower rear gear (2.97 1st and a sub 3.00 rear gear) for the 200mph stuff and perhaps a 3.42 rear for the drag stuff.

Maybe keep the gearvendors and put it on one of Jamie Passons 833s?

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Re: Setting up car for both low speed, and High Speed

Post by pdq67 » Wed Apr 20, 2016 11:14 pm

autogear wrote:If you shift into 5th under full power in a T56; theres a solid chance that eventually its going to hemorrhage parts of gears.

I might also mention that the viper T56 still uses the GM F-car double and single cone synchronizers for 1-4. Its only real blessing is the larger output and Mopar specific input.

I would seriously talk to one of the 6-speed specialists about building you a custom gearbox that uses the GTO/Corvette double and triple cone synchros or skipping that entirely and going to a TR6060 which has wider gears and uses a Getrag-style synchro system.
Dave Guffey at RPM Transmissions in Indiana is a great place to start
I'd also mention:
RKT56
D&D Performance
Hanlon Motorsports

There are certainly others, but these are the ones Im most familiar with. I might also consider a single OD and a numerically deeper 1st gear and numerically lower rear gear (2.97 1st and a sub 3.00 rear gear) for the 200mph stuff and perhaps a 3.42 rear for the drag stuff.

Maybe keep the gearvendors and put it on one of Jamie Passons 833s?

I sure wish A/G would reconsider the Muncie 5-speed like I have talked about.

One with the 5th gear OD in the tail housing and exterior shifted like a stock Muncie.

pdq67

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