Retard with an lencodrive

Hello

We are working on a 6.50 index Funny car(heavy!!!) with a 2 speed Lencodrive, 540inch AJ chev 16/71 in Australia.(6.66@208mph) We running fairly low boost and we are seeing way to much of an rpm/boost drop on the gear change. I was wondering if anyone has tried retarding the ignition on the gear change. In theory i am trying to make more torque, help the convertor lock up and then the engine to accelarate faster out of the low rpm/boost situation. I have seen this work on clutch cars.

Has anyone tried this with an auto or am I wasting my time.

Thanks

Clarky

 

Ignition Retard

If you are going to go with an ignition retard, there are now a few guys in Oz using to MSD 8973. I have just purchased one for my blown altered and am awaiting it's arrival.
After looking around, this seems to be the best option, for us anyway.

http://www.msdpromag.com/8973.htm

 

8973=bad bad bad
You can use a 6 shooter, EM Timer, and pneumatic/elec solenoid to accomplish this. I don't know if it works or not and I do run a converter in TAD. Talk to Dave Leahy and he can set you up. I would be interested to know if you have any success with this.

Brandon Booher
NHRA TAD #34

Sent from my IPad

 

Bad?

What is the problem with an 8973 for this application?

 

We have run the 8973 for years never a problem I would much rather use it than a 6 shooter if it is legal in your class,,, BUT! what Will said ,, gear ratio and maybe converter probably need more rear gear Will said it very well
P.S. ( has someone had a problrm with a 8973? we love it)

 

Thanks Will ideally we need to put a 3 speed in the car and split the first gear ratio in half but there is no room. convertor is pretty much spot on 4-6% slip. Will look at ordering some smaller roll out tyres next time and see how that changes things.

Aside from that we already have a 6 shooter and leahy box so i dont really need a 8973 to complicate things

 

Sorry mate, if l new you already had a six shooter l wouldn't have made a suggestion.

Only had positive comments on the 8973 from those l have spoken to.

 

You will probably find that if you talk to 10 people, you will get back 10 answers. There were several rumors that the P/S guys were screwing around with timming as you'd described; however, they would add 1-2 degrees of timming at the hit, and, from there, take .5 degrees out on each gear change, but, many went back to the standard deal. Although, some, will take out timming in the event of slipping the tire and/or gear changes. I would say, based on your slippage numbers, that you're close to where you want to be. While you hear stories about people having 1 percent slippage, it's hard to verify. We always try to go for 5 percent slippage as a standard. It just begs the question of your stall speed relative to what your dyno numbers are. Simply stated, you would want to start out at your peak tourque as your starting point from your stall speed. There are some other variables that are never talked about with a converter in relationship to fluid dynamics and how it effects the stall, and, in addition, torque multilplication. That being said, you can go about what you're doing in two ways, one, being torque multiplication in your converter, and, second, thru your exhaust tunning. In a perfect world, for a converter guy, you would love to have the cake and eat it too in terms of being loose on the bottom and tight up top. Much like a clutch where you can slip the clutch on the bottom via your base and lock the clutch up on top via counterweight up on top. John Lingerfelter had this thought when he ran a powerglide in a/d via fluid restriction in his transmission back in the late 80's. As a result, he was able to run a loose converter and throw more torque multiplication to the converter as a result. Lock up the converter after the 1-2 shift and gain what could be lost up on top as a result of the coverter slippage. The other thought is your tunning via exhaust. You can tune your exhaust to effect your tourque curve via different lenths. While Norm Grimes used it once, I'm surprised that you don't see more people using the idea, especially in the ADRL deal. You can increase your torque that way too via exhaust tunning, but, none of the TAD guys have looked at this as a viable option. If they have, they probably won't say..lol

That being said, I don't know about the Lencodrive deal if anyone has tried to do a lock up type setup via fluid restriction. But, I would try a converter that would have more torque multiplication with the same effective stall if you're happy with that. For instance, if your converter has 1.5 torque multiple, maybe, you could try a converter with a 1.6 torque multiple. The increased torque will allow you to accelerate the car harder. However, you would see there's a fine line to where too much would leave the car prone to spining the tires off. In the event that works, from there, you could see if you can throw more 1-2 gear at the car to see how it likes it. You may find that it's a fine line there. In the event that you do you do that, you may have to fine tune your rear end gear accordingly to how hight you want your trap rpm to be.

 

Thanks for the reply Gil

We are currently going the gearing route, lower diff gears to hopefully free enigine up in to top half of the track + taller front pack to compensate on the start line. The guy who builds our Lenco drive has devised a pressure regulator for the trans you described and we will have access to one in March to try. there is atleast one auto pro mod in Australia using his device already. Once we had sorted the gearing out and the pressure reg I will Knock some timing out on the shift and see if it does have the same effect as a clutch car.

A link to the car from the weekend (blue chev)

Clarky

 

link to runs

http://www.youtube.com/watch?v=3Wtvyn6mqCU

 

the RF bounces around under the body. They work well in door cars because in most instances they are behind a steel firewall.


sounds like a urban legend will...that is just flat out non-sense! and by the way ..the 8973 will not be gone anytime soon..get the facts straight !

 

Who that runs well actually runs an 8973? Leahy has his new Power Module out and it does everything the 8973 does and it's much easier to operate. The only reason someone would still have an 8973 is because they don't use it (it's just on the car), or they don't want to spend the $. I cannot think of a single TAD or TAFC (worth their salt) who runs an 8973. I'm not as familiar with the PM community but as Will said they seem to work better on the PM. I refuse to believe that a few guys on this board are smarter than the brightest minds in alcohol racing who threw them out when they were malfunctioning for no reason.

Steve L.