Sintered iron race clutch discussion (was: Pro Spyder intake?)

[ultraflo]

Here's a better example of where the access hole is relative to the trans... I just use a standard allen wrench to make adjustments.

[ultraflo]

here's another pic of the assembly apart....

[StangFlyer]

Cool. I am going to start out with just one turn on mine, which should give me ~990 lbs or something like that. But, I'll have 9 grams of counterweights on it also. The counterweights, in my line of thinking, should allow you to use lower base pressure while still allowing it to clamp down hard as the RPM comes up and the additional clamping force comes in from the weights...

How much slippage do you get launching your car before the clutch really clamps in with your current set-up?

Oh, and I'll take your Jerico!

[ultraflo]

Originally posted by Dan McClain
How much slippage do you get launching your car before the clutch really clamps in with your current set-up?

Well... with the 28x10 Goodyears, once I got the clutch to actually work properly I just left it at 7, which was a solid lockup. I re-directed my attention to getting the nitrous tune-up dialed in. I was leaving with some minor tire spin with the Eagle slicks, and could've benefitted from a little slippage off the line to keep from shocking the tires loose. After swapping to a set of M/T ET drags, the car turned into a wheelie machine... which was a total shock to my system! I realized that I essentially had to start from scratch on the suspension settings and the two days that I ran on the Mickey's were spent trying different shock and strut settings to keep the nose down some. In hindsight, I could've taken some bite out of the clutch, though I'm not sure how that would've worked out. I still have a ways to go before really getting a feel for the correct clutch setup...

As for counterweights, I'm not sure how RAM does their kits, but the McLeod unit comes with a pack of steel allen bolts (1"=8g. ea., 3/4"=6g. ea, 1/2"=5g ea.), steel nuts (3.5g. ea.), aluminum hex bolts (1"=3g. ea., 3/4"=2.5g. ea., 1/2"=2g. ea.), aluminum nuts (1g. ea.), and steel barrel weights (3.5g. ea.). Included with this pack is a few pages of info explaining the function of a counterweighted type release lever. You can either add these weights to the inboard or outboard position of the pivot point of the lever, with the outboard position being the one that adds pressure to the clutch.

Will you be trying 3 grams on each lever (9g. total) or 9 grams on each lever? Reason I ask it that in the lit. I got with the unit I use there is a note: "C/W can make the car hard to shift at high RPMs due to the tremendous effect it has on weak clutch linkage and also increasing pedal effort. C/W can also make the car push thru the starting line causing a red light. This is because after staging, when you bring the RPMs up, the C/W comes in forcing engagement. For these reasons in manually shifted trans. apps., C/W is added very lightly, if at all. Therefore, to regain lock up during gear changes, slightly increase static pressure only. This will have no effect on staging of the car of during shifts."

Hope this helps some.... and no you can't have my Jerico, LOL! That's my favorite part of the car! ...plus, it would destroy the street manners you enjoy with your 'stang.

[StangFlyer]

Yeah, 9 grams total. I have the exact same type of bolts and nuts in a pack with mine. I have three aluminum pairs and three brass pairs. I dare say they weigh about the same.

Sounds like you really aren't taking advantage of what this clutch configuration is for yet though. Other than just being able to hold gobs of power/torque, it gives you the ability to use low enough base pressure to allow the clutch to slip during launch (60 ft) enough to let you hook up. Then as RPM's come up it locks-up and 100% is to the wheels. That keeps you from blowing the tires and from killing drivetrain parts.

I will personally have to rely on this a lot. With the street set-up my trans will probably live. However, with the race configuration it would most assuredly die a painful death without utilizing this clutch to allow off the line slippage. Unfortunately, I don't have a Jerico and I've got a Tremec TKO behind this beast. Workable for the street config with 100% off the line lockup, but for the race config it's out of it's league.

My plan is to adjust mine so that for track duty, it will slip just enough off the line to allow me to hook with the bigger boost, keep my trans alive in the process, but once I'm moving to have 100% lock. Now, actually Mike (owner of RAM) told me some time ago that Cory Roth was running this set-up. Supposedly, he was only using 400 lbs base pressure, but then had the counterweights on also. I'd have to check old emails to find the details.

[ultraflo]

Sounds like you really aren't taking advantage of what this clutch configuration is for yet though. Other than just being able to hold gobs of power/torque, it gives you the ability to use low enough base pressure to allow the clutch to slip during launch (60 ft) enough to let you hook up.

Exactly... I could've benefitted from using some light C/W's and less pressure with the Goodyears, I imagine. With the power I was making combined with the 28x10.5 M/T's, I had all the hook I could ask for... too much, really. The Goodyears offered a best 60ft. of 1.401 while the swap to M/T's netted a best of 1.342, both were achieved with 1110lbs. of pressure and no C/W's combined with a 200hp shot of juice. I have yet to establish a preliminary game plan, as far as the clutch goes, with the new combo. I don't plan to be too far off from what I ended the year with, other than a stronger block, a different cam, and a second stage of nitrous later into the year. I would like to get away with not using the C/W's and see what I can accomplish through tuning the static pressure alone. Should I add C/W's you'll more than likely be one of the first to know, as I will be e-mailing you to see how things are going with your clutch tune... Cool?

Thanks Dan,
-Ryan

[StangFlyer]

Absolutely Ryan. I'll be testing it out as soon as spring gets here and playing with tuning it. I will get this done over the winter finally. In fact, our discussion has actually gotten me a little more excited to go wrench on it again. ahahahaha. Of course, that means I can finally do the project section for the car too and I'll detail everything with the set-up on the site there, as well...

Btw, you have some good 60 fts there. The best I ever did with my 302 combo was a 1.45, BUT now we're talking a whole different animal with what I have now eh. We'll see how it goes next season...

[ultraflo]

In fact, our discussion has actually gotten me a little more excited to go wrench on it again...

Excellent... ...can't wait to see what you get out of your combo! It's good to have someone to compare notes with, as far as this adjustable clutch business goes.

Take care,
-Ryan