Engine/Tranny Question

[Dave Haller]

I'm in a bit of a delema. I have a 481 inch BBC, running a Ron's Terminator Injection system hooked up to a Turbo 400 that has been beefed up. I ran with no problems at Speedweek 08. The engine came on strong in first gear, 2.48, second gear 1.48, then dropped to 4700 rpm in third, 1 to 1, and lugged to the best of 5900 in that gear. I kept changing out the rear end gears ending up with a 2.47 and speed of 213 which is way low for what I was trying to do. Shift points in 1st and 2nd were 7500 rpm. I'm running methanol for fuel, compression in the engine is about 13:1. Tires are the M/T 30", fronts are Goodyears 23". I know my scoop is way to big and the engine compartment is open. Any suggestions on horsepower needs, transmission gearing, transmission recomendations. I know Danny Boy shifts quickly with a Liberty trans with minimum rpm drop between 3rd and fourth as well as fifth. Any help is much appreciated,
Thanks,
Dave Haller #93 A/FL

[doug odom]

Dave, I love my Liberty. You can get any gear ratio you want.
Mine is
2.50 first,
1.50 second
1.25 third.
1.10 forth
1.00 fifth.

[Dave Haller]

Doug,
That is what I am considering. Do your ratios keep the rpm's up in the power band between shifts? I have some numbers worked out and they are close to yours.
Thanks,
Dave Haller

[Sumner]

Dave we are running a G-Force with 1.923-1st, 1.331-2nd, 1.000-3rd, and 0.931 4th.  4th is actually  the 3rd gear cluster and you can pick lots of different overdrive ratios for it and you run the 1 to 1 fourth as 3rd.  We only drop about 500 rpm on the 3-4 shift this way.

For the speeds you hope to run I would look at their 5 speed, GF-5R, as you could then run the 5th 1 to 1 as 3rd (check with them) and run 3rd and 4th as overdrive gears to keep the rpm drop at the top end low with close ratios.

http://www.gforcetransmissions.com/tran_gf5r.asp

For instance with that transmission you could run a high 1st like we do of 2.00.  We still can't use more than 50% throttle in 1st with the added weight, so I don't see where a lower gear would help as we would then probably spin the tires easier.

http://www.gforcetransmissions.com/pdfs/GF5r_ratio.pdf

2nd could be a  1.38 and then the 5th would give you a 3rd of 1 to 1.

The 3rd gear set then could be like a .87 and the 4th gear set could be as high as .776 if needed.

Those are just numbers I picked at random.  You need to be realistic about the cars top speed and then use my "RPM in gears for 5 Speed Car Transmission" spreadsheet....

http://purplesagetradingpost.com/sumner/bvillecar/bville-spreadsheet-index.html

.............. and plug in different gear combinations and look at different rpm shift points and look at the rpm drop after the shift so you pick ratios that keep you in the power band.  All of that is right there and easy to see with the spreadsheet.  The first couple rpm drops can be large and will help to keep from over powering the tires, but the last need to be very close.

Missed meeting you on the salt,

Sum

[doug odom]

Dave, I have mine so the last shift 4-5 drops 10%. If you are shifting at 7000 it will drop to 6300.  I have a quick change with a 2.3 ring and pinion. I just looked up my gear chart and I missed the ratios a little. The real ratios are
First     2.17
Second 1.52
Third    1.27
Forth    1.10
Fifth     1.00
I have a real nice spread sheet that someone sent to me and I forgot who. I can email it to you if you have excell and you can work out what gears you need.

[desotoman]

Dave,

Have you had the motor on the dyno? If so what were the results? When you say you changed gears what gear did you start with and what was the rpm you were running with that gear? If your motor is not up to par it does not matter what transmission you run.

Tom G.

PS. Post a picture of your car.

[Dave Haller]

Tom G.
I didn't dyno the engine. I have a friend up here that has a chassis dyno but the car is set up with a direct drive, no torque converter so putting it on his dyno was not an option. The estimated horsepower is close to 900 based on the engine builders stats. It does come on very strong in first and second buzzing to 7500 with no problem. I think keeping it up in the rpm power range is the answer as well as using a smaller opening on the scoop and enclosing the rest of the car.
Dave H.

[desotoman]

Dave,

IMO do yourself a big favor and put your motor on the dyno, and see where the peak torque and HP are. Then you can see what exactly your RPM range for making power is and not be guessing. It will be way cheaper than buying a $5000 transmission especially if you don't need it. Remember that motors will aways pull good in 1st and 2nd as you don't have the drag that you encounter until high gear.

I helped a friend run his lakester back in the mid to late 1980's at El Mirage. It was a real budget car, old rear engine dragster, no covering of the motor, headers stuck well into the breeze, front of the car was covered but no covering of the roll cage and no wind deflector. With a basically stock 327, with a 3/4 grind cam in it, we were able to run a best of 178 at El Mirage on the 1.3 mile course. (if this car had 300 honest HP I would be amazed) For a transmission it had just a two speed lenco with a 1.44 first gear, and as I recall we had 3.08 gears in the rear. The car was driven off the line not pushed.

When I bought the 300 Street Roadster the motor had been blown up at the last meet of the season at El Mirage. I scrounged up some junk parts just to be able to run the car. The motor parts I found were a 350 with 10-1 pistons, cast crank, stock cast pressed pin rods, two bolt main block, stock oil pan and pump, Comp Cams 280 degree hydraulic cam, Early Corvette heads era 1965 with stamped Chevy rockers, the only parts I was able to use off the blown up motor was the single 4 barrel intake manifold with the 650 Holley, and the MSD crank trigger and distributor. Transmission was a turbo 350 that has special kilgore gears in it that are 2.42-1 in first, and 1.42-1 in second. Rear end is a speedway mini quickchange. This car ran a best of 163 mph with that motor at El Mirage, with a 6000 RPM chip in the MSD unit and 2.95 rear end gears. We would go through the lights around 5700 RPM, just where the cam was peaking.

If I had a 900HP motor in my street roadster it would go around 210+ at Bonneville. I am not trying to tell you what to do, only trying to help. Good luck with whatever you do.

Tom G.

[Stan Back]

Speaking of running good in first and second gear -- our first run at Bonneville this year we set what I believe to be a record.  Past the 1 with our internal injector cover on.  Ran pretty good in 1st and 2nd -- just wouldn't pull in third.

Stan Back

[Dave Haller]

Tom G,
Can you email me at my home? dhhaller@comcast.net. I would like to share and receive more info on my set up and don't want to tie up this chat room with stupid questions. I have lots to share.
Thanks,
Dave Haller

[jimmy six]

Dave, I use a Tex T-101, very similar to the G-Force. 1.60 1st, 1.23 2nd, 1.00 3rd, & .96 4th. Tex can assemble any 4-speed trans you want with pristine used Nascar gears and used aluminum cases. Their T101A is tricker but not really necessary. I just purchased a 2nd one off E-Bay for $1000.00; a little different gearing but still with an .945 OD.

Mine are both clutchless but we still use it in the first 2 shifts. Last one we just yank it. Gearing changes ment dissasembly of the trans but gear sets were only $75.00. I believe Bob Brissete uses a similar trans in his lakester.  As these NASCAR suppliers change to the "newest and best" the older equipment is pretty reasonable and for what I have found bullet proof for us. There are more of the OD and very close ratio transmissions on the salt than you can imagine...Good Luck ..JD

[836dstr]

JD,

Do you have the contact info for Tex T-101?  Looking to change trans combo next year.

Tom

[jimmy six]

www.texracing.com was how I did it after talking to Keith Turk. Everything you need to see is on the net. I had them send me a complete gearing chart for the T-101 and I made my choices from that. Did it all over the phone. Because of the lack of room I had to use a Hurst shifter but would have preferred the Long but it would not fit.

It came with an oil spray bar but I did not get a pump or reservoir; same reason lack of room. They "appear" the same as a Muncie or BW-T10 in demensions but they are massively strong. I had to make a custon cradle to fit my floor jack to put it in. I weighs in at a little over 100#. They are a "work of art" inside. Good Luck.............I now carry an extra

[836dstr]

Thanks JD,

I'll check it out.

Tom

[Dave Haller]

Tom G.
Emailed you last night but got an error message back. Sent it again this morning. Let me know if you got it,
Thanks,
Dave Haller