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Finally got to the track. Got up on 2 step and tried to launch. Trans said no thanks lol. Pump gas tune, 13psi on 2step, Hoosier stiff wall slicks. Undecided on direction. Not sure a Magnum would last for the investment vs th400.
Just like Bob who always said the Nova and SS will always be T56,I think you're gonna go Auto. The 'cushioning' effect of a convertor(even thou you'll be going 4000-5000 stall rating) doesn't play hell on the driveline.
We will see Denny, exploring all my options. Not sure how much I want to invest in staying manual. Magnums aren't cheap, and they aren't cheap to fix either.
Short torque arm, MWC chassis mounted. Mainshaft exploded, pushed on driveshaft, and let it take out the tailhousing. Car makes 1051/901 at the wheels. Perfect prep, slicks, 13 psi on 2 step. Little 27 spline couldn't handle it
D&D chuckled and said its time for an auto. I talked to pretty much everyone I could. RPM, D&D, Liberty, G-Force etc. Never heard back from Rockland.
Plenty of 6060/magnums living at your power level. What are you running for a clutch? Side stepping off the line or slipping? You did pretty good with that 27 spline main....I'm 100hp/tq less than you at 3740lbs and my stock main is hanging on for dear life I'm sure lol.
A clutch like yours is going to destroy drivetrain parts every time at your power level. Just this year at my local track I have seen multiple broken axles, wheel studs, driveshafts, differentials and last Saturday a TKO. All were friends with McLeod twin disc clutches.
When I built my last engine and got the T56 Magnum I didn't want to be tearing **** up every week so I went with a soft lock clutch that is designed to slip so you dont shock the drivetrain.
The clutch is an Ace NexGen from Cale Aronson at Black Magic Clutches. It is a 10" single disc clutch but Cale is a clutch expert and will set you up with whatever your car requires.
Not sure a single will be upto 900ft lbs torque in a 3500+ car. Plus its a street car, not sure how a slipper will like street driving. I will give him a call though. Learning something never hurts.
A clutch like yours is going to destroy drivetrain parts every time at your power level. Just this year at my local track I have seen multiple broken axles, wheel studs, driveshafts, differentials and last Saturday a TKO. All were friends with McLeod twin disc clutches.
When I built my last engine and got the T56 Magnum I didn't want to be tearing **** up every week so I went with a soft lock clutch that is designed to slip so you dont shock the drivetrain.
The clutch is an Ace NexGen from Cale Aronson at Black Magic Clutches. It is a 10" single disc clutch but Cale is a clutch expert and will set you up with whatever your car requires.
The clutch, including flywheel weighs 26lbs.
Softloc is a maintenance hassle and while effective at softening launches, engagement after a WOT shift will be anything but soft due to it gaining clamp pressure with rpm. If you have a logger, just look at the spike in wheelspeed after a shift. A proper clutch tuneup for the track means seeking a balance between slipping enough to launch effectively, without slipping so much that it blows thru the clutch in the bottom of high gear. If you take that same clutch tuneup to the street, any use of low rpm power is going to smoke the clutch. This is because the clutch is tuned to a higher rpm and won't have enough centrifugal assist to handle much low rpm power. The common solution is to have a different clutch tune for the street than at the track, which generally requires jacking up the car. That extra work tends to reduce the fun factor, also no more spontaneous encounters on the street.
The op's McLeod twin can be a far better choice for a street/strip car. It has plenty of capacity to hold power, problem is overly harsh engagement. The popular "drill mod" only makes it worse. The problem with the original orifice design was that it slowed clutch engagement throughout the pedal release cycle, which kills reaction time. Drilling out the orifice improved the reaction time, and made the car quicker. That works great with a stock clutch, as it's near it's capacity and will slip a bit. With the increased capacity of a twin, that mod works against you and engagement gets way too harsh for the rest of the drivetrain.
How do you fix the shortcomings of the twin?
You could install a simple adjustable orifice in-line to buffer clutch engagement. This can work great for launching from a full tree where you can anticipate the launch to make up for the increased reaction time. This is exactly what the ClutchMasters and Tilton units do. The problem then becomes that the orifice also slows down your shift times when using the clutch pedal.
The next logical step might be a system that uses a solenoid that allows the orifice to be effective only during launch, but dis-abled for shifts. Easy to do with a line-lock solenoid that is activated only during launch, allowing fluid to bypass the orifice during shifts. This is exactly what the Magnus unit does. Problem is it fixes the shift time problem somewhat, except now the drivetrain sees the full violence of the twin's harsh engagement during shifts. This will keep you from being able to run radials consistently at the track. Also, reaction times still suck unless you are launching from a full tree.
What's the next logical step to fix both shift harshness and reaction times? my solution was to come up with a device that is only active during the actual engagement part of the clutch pedal's release cycle. It was a simple device that used a hydraulic screen door closer that I bought at Lowes, with a few modifications. I called it the "Hillbilly Clutch Slipper", worked great. I made some refinements over the years, also made it more compact to fit other applications. Changed the name to ClutchTamer, then made application specific brackets for the FOX Mustang. At the recent NMCA/NMRA SuperBowl event, the top 5 qualifiers in Coyote Stock were all manual trans cars using ClutchTamers to manipulate the lockup of their clutch. One of them, Charlie Booze Jr, won the event. This is a super competitive class that uses factory sealed crate engines, spec fuel, they even flash the cars in the lanes to make sure everyone is using the spec tune. Automatic cars are allowed any welded body converter and a trans brake. The manual trans cars are required to run a minimum 10" dia diaphragm clutch. The class also runs on a .400 tree. Delayed reaction times are not an issue, it's a proven concept.
My point is that with a little fabrication skill and some ingenuity, the op's problems with his twin could be overcome with hardware store parts for under $50. There would be no need to crawl under the car to change clutch settings from street to strip, he would also likely be able to run radials and eliminate the hassle of changing tires at the track.
If your racing often? At those power levels an auto is a no brainer imo. Even with a slipper the trans is going to hate you. Honeycutt ran the dick out of 6spds and was rebuilding them every pass with face plating and all once he got north of 800whp. Put a glide or a 400 in it or a 4L80 if its a street bucket and go.
Or stop tracking it so much and live with soft launches. All difficult choices I know
Put in a RPM T56 Magnum. See how the 31 spline mainshaft does. Will say that the trans has no notchiness at all. Huge change in feel from the past 10 years of notchy T56 driving. Track Rental in 2 weeks, see what happens.
Put in a RPM T56 Magnum. See how the 31 spline mainshaft does. Will say that the trans has no notchiness at all. Huge change in feel from the past 10 years of notchy T56 driving. Track Rental in 2 weeks, see what happens.
I did the CF blockers, billet keys, steel 3-4 and dressed the gears when I built mine. It was smooth as butter for the first season and it became a lot notchier after use which is likely the sharp edge dressing I ground beginning to round off. It still shifts excellent at full jam though, very fast and accurate but it is notchy at slow speeds. Thought id mention this as food for thought
Put in a RPM T56 Magnum. See how the 31 spline mainshaft does. Will say that the trans has no notchiness at all. Huge change in feel from the past 10 years of notchy T56 driving. Track Rental in 2 weeks, see what happens.
I would slip the clutch at the launch, unless you like replacing transmissions on a regular basis...
08-26-2017, 11:32 AM
T56 carnage 
