TU Purple Plate + 6 Puck Ceramic Clutch = Not Enough

[jckrieger]

I've been tuning my car on E85 with 106 lb/hr injectors for the last 2 weeks and have found the limit of the TU purple pressure plate. The clutch is the most awesome unit ever, but it does not hold 30+psi on my 2.5L Luckily, the clutch only slips when the boost spikes a bit over 30, but fully engages again when the boost settles around 25-30psi (need to stabilize my boost control).

So basically, if you want to build a torque monster that runs on alcohol, get a Spec clutch or a dual diaphragm pressure plate.

-Clark

[DodgeZ]

guess on power level?

[Chris W]

I've been tuning my car on E85 with 106 lb/hr injectors for the last 2 weeks and have found the limit of the TU purple pressure plate. The clutch is the most awesome unit ever, but it does not hold 30+psi on my 2.5L Luckily, the clutch only slips when the boost spikes a bit over 30, but fully engages again when the boost settles around 25-30psi (need to stabilize my boost control).

So basically, if you want to build a torque monster that runs on alcohol, get a Spec clutch or a dual diaphragm pressure plate.

-Clark

The 6-puck was designed to be a more streetable clutch with HP/Torque limitations. Your set up sounds like it may be ready for the 4-puck disk. Let me know if you would like to move to the next level.

ChrisTU

[jckrieger]

The 6-puck was designed to be a more streetable clutch with HP/Torque limitations. Your set up sounds like it may be ready for the 4-puck disk. Let me know if you would like to move to the next level.

ChrisTU

I think I will fix the boost spike and live with a little reduced power. The car just burns the tires through 3rd with the OBX and the 3.50 final drive. This power level is just stupid on the street, but the clutch actually behaves very well.

[jckrieger]

guess on power level?

If I had to guess, I'm thinking around 400 crank hp and maybe 450 ftlb of torque? The car is nothing like anything else I have driven. Time to take it to the track!

[shadow88]

With the purple plate and the 4 puck, I put 447 tq to the wheels. I'm aiming for 470 to the wheels this year and the purple/4 puck hasn't hinted at a slip yet.

Sounds like your clutch selection doens't match your power selection. I agree the purple plate feels very streetable.

[jckrieger]

Could the 4 puck disc really make that much of an improvement over the 6 puck disc? I'm thinking a strong pressure plate might be required to get a significant (20%?) improvement over what I have now.

[Force Fed Mopar]

Less pucks = more pressure.

[jckrieger]

Less pucks = more pressure.

More pressure over less area doesn't always mean more friction though. Of course, we all know a wider tire should always have more friction than a narrower tire of the same construction.

I'm just not sure the difference would be significant enough. I'll have to dig up Chris' number from way, way back when. I believe he had break away torques for some of his pressure plates posted somewhere.

[SUPER60omni]

I made 600 Ft/Lbs with NO problems with the purple plate / 4 puck setup. Not sure how its failing in the 4's

[Mario]

I made 600 Ft/Lbs with NO problems with the purple plate / 4 puck setup. Not sure how its failing in the 4's

He's using the 6 Puck.....

[turbovanman²]

What's you setup?

[Ondonti]

spec clutch is garbage....Art had big problems with his at 400hp. That was a stage 5.
Probably comes with a junky plate. Maybe try their disc with a decent plate like you already have. Only problem is that your plate is a bit thinner to work with chris's thicker discs.

I run a 3 puck. it definitely grabs harder then a 4 puck. Ive found that a clutchnet 6 puck will hold insane power if combined with a non clutchnet plate (they are junk) but chris's are built specifically with his parts in mind so a simple jump from 6 to 4 pucks should sooth your wounds. Hit up all the surfaces with some sand paper and keep things cleaned off if you swap it.

[omni_840]

What's you setup?

+1 on this

is it your csx or glh?

[jckrieger]

I may have to go with a 3 puck, though I don't really want to spend a bunch more money on a clutch that was already basically the most expensive clutch I could buy at the time (that's worth a damn anyway).

Since the car is just stupid to drive on the street at 30-35psi, I'll probably just turn the boost down a bit since a stronger clutch would probably yield a broken input shaft.

[jckrieger]

What's you setup?

This is in my 87 CSX... GLHS is still bone stock.

Setup is as follows:
-89 Common block 2.5L with forged Wiseco pistons
-Home ported cylinder head with reshaped combustion chambers and stock valves
-Stock roller turbo camshaft
-Lightly ported 2 piece intake with 52mm TB
-Ported exhaust manifold with 3" mandrel bent exhaust
-S50 TO4E compressor in TO4E housing with a Stage 3 "F" .63 A/R turbine housing
-Big FMIC (Treadstone)
-106lb/hr Delphi injectors with E85 fuel and a home-brew ECM calibration

A billet fuel rail has been on order from FWDP for 4 weeks... I'm sure poor #1 is starving for fuel. WB Lambda is set to .7 for WOT operation.

Trans is a 520/555 with a 3.50 final drive and an OBX diff. Clutch is the large diameter disc 6 puck ceramic with the purple pressure plate (installed last year, about 2,000 miles ago)

Future upgrades include a baffled oil pan, PT lifters (running Neon lifters now), and some kind of aftermarket roller camshaft.

[jckrieger]

I made 600 Ft/Lbs with NO problems with the purple plate / 4 puck setup. Not sure how its failing in the 4's

How much torque does a 2.5L make at 35psi with aggressive timing on alcohol?

[Ondonti]

Do you have the small or large input shaft? You are not going to break the large one and probably not the small one either....since nobody has that I know of. I did an insane dryhop (failed burnout when water box was closed) that felt like it was tearing my car apart. Axle went on the launch but no other problems. And we have really strong axles. They are thicker then the input shaft.

I believe Reeves is running a small spline and he split his transmission in half from a seized bearing before ever having an input shaft problem. So the input shaft was strong enough to split the trans.

[GLHNSLHT2]

yea reeves has the small input shaft.

[jckrieger]

The only reason I was questioning the input shaft is because I've seen videos of SRT4 neons breaking the input shaft on the highway. I figure the small spline shaft should be even weaker, though there is a possibility our shafts are stronger since I have never heard of anyone breaking one on a non-neon trans.