MCleod RST, RXT clutch

[BruceH]

OMG, you launch at 6K???

I launch mine at 3,500 on 2nd gear. Stock clutches cannot handle those types of launches. I shift at 7,600 RPM.

The RXT is an excellent clutch that can handle lots of abuse. But it needs to be exactly installed per McLeods instructions. Also get yourself the McLeod flywheel along with the RXT. Do not get the RST, it will not handle racing.

Having owned and raced with two RST clutches I disagree with your statement. I have even hot lapped with 14 runs in about 3 hours on multiple occasions.

Once again all I can do is give you my actual experience. How did your RST fail?

 

[Falkinman]

Yes, 6,000 dropping the clutch results in good sixty foot times and it lifts the front wheels off of the ground. You launch in second gear at a drag strip? And you have a supercharger so it's a lot different, you would blow the tires off if you launched higher. Do you lift when you shift at 7,500?

 

[Falkinman]

Bruce, what rpm do yoh launch and what rpm do you shift? Do you lift when you shift?

 

[AutoXRacer]

Having owned and raced with two RST clutches I disagree with your statement. I have even hot lapped with 14 runs in about 3 hours on multiple occasions.

Once again all I can do is give you my actual experience. How did your RST fail?

My disc clutch warped, the one on the flywheel side. McLeod thinks it was due to hot lapping. It held great until I couldn't shift into gears anymore due to disengagement issues. McLeod upgraded my clutch disc to RXT. I have never looked back.

Yes, 6,000 dropping the clutch results in good sixty foot times and it lifts the front wheels off of the ground. You launch in second gear at a drag strip? And you have a supercharger so it's a lot different, you would blow the tires off if you launched higher. Do you lift when you shift at 7,500?

Yes, although I shift, when I engage the gear its RPM matched. I can't afford to power-shift as it will loose traction...yes, even in 4th gear.
I don't have the best setup for drag racing as my car is mostly setup for road courses. So I know my weigh shifting is basically non-existent.

 

[BruceH]

My disc clutch warped, the one on the flywheel side. McLeod thinks it was due to hot lapping. It held great until I couldn't shift into gears anymore due to disengagement issues. McLeod upgraded my clutch disc to RXT. I have never looked back.

Mine had slipped due to my error and burned. However, I let it cool down for an hour and then drove like I was breaking in a new clutch. The next week it held just fine. Everyone at the track thought I'd be lucky to make the 90 mile drive home. Glad I didn't call a truck or have it taken to a garage.

How much were you hot lapping? My record is 6 passes without a cool down. Make the run, drive back to the line and do it again, etc. I burned the clutch by slipping it too much. It stunk bad. I hate that smell. When it was taken out it still looked good and afaik it's still working. Sold it when I went to a 26 spline 6060.

 

[Falkinman]

AutoX, no offense but I need info from drag racers only. The way you drive your car for autox is completely different.

 

[BruceH]

AutoX, no offense but I need info from drag racers only. The way you drive your car for autox is completely different.

FYI I'm not a drag racer. I'm a test n tune guy. The RXT is probably your best bet although I don't know if it has the same recovery from burning like the organic RST does.

At one time McLeod didn't recommend the RXT for drag racing. That was when the disks used bronze instead of the ceramic it now uses. A dual disk metallic disk can fuse to the floater plate.

You really can't go wrong with a McLeod twin disk imo. Others have had bad results but it's always someone who paid to have it done. Those of us who do our own work read the directions because we don't know it all. That's my theory anyway. Of specific concern is the factory shimmed floater plate and the floater plate ring. Exceeding the torque value call outs on the floater can lead to warpage, something you want to avoid. The torques are very low and doing it till it's goodntight will cause warpage.

 

[Falkinman]

thanks Bruce. The reason I'm asking all of these questions is because the last time I research this about 2 years ago, I called McLeod and they did not recommend RXT for drag racing. at the time they said it was because the RX T was a diaphragm clutch and diaphram clutches were not recommended for shifting at over 7000 rpm.

 

[BruceH]

thanks Bruce. The reason I'm asking all of these questions is because the last time I research this about 2 years ago, I called McLeod and they did not recommend RXT for drag racing. at the time they said it was because the RX T was a diaphragm clutch and diaphram clutches were not recommended for shifting at over 7000 rpm.

Good, so I'm not having phantom memories about the rxt not being for drag racing, lol. Apparently they have changed their mind. I was so happy with the RST that I bought another one when doing a 6060 swap. I especially like the incredible holding ability combined with low pedal effort that ensures the slave won't take too much abuse. It also makes the driveability on par with stock. I've had a slave go out with a centerforce clutch and can tell you that it sucks to change a clutch you just changed a month before.

You have other options. Exedy makes some nice organic clutches that hold decent power. I'd think that there is a version of the 07806 for a MT82 spline count (33?). I'm running one now and it works just fine.

 

[AutoXRacer]

AutoX, no offense but I need info from drag racers only. The way you drive your car for autox is completely different.

AutoX, who autocrosses an 800HP car...? I drag race, do track days (road course), and autocross (to hone in my driving)...along with any type of racing I can participate in (drifting, roll racing, etc).

But Bruce is right, I also recommend the RXT...it the last clutch you will ever buy and it takes all the abuse you can throw at it.
Sure its a little over-kill for a NA setup...but it will be the last one you ever buy. And the pedal effort is softer than stock.

 

[Falkinman]

Ok, thanks for clarifying the type of racing. So when racing do both of you guys do no lift shifts at 7,000 or higher?

 

[AutoXRacer]

I lift because I'm so close to the rev limiter and i don't want to bounce off of it.

 

[Falkinman]

What rpm?

 

[AutoXRacer]

7500; limiter is 7,700.

 

[BruceH]

Ok, thanks for clarifying the type of racing. So when racing do both of you guys do no lift shifts at 7,000 or higher?

I haven't been out with my current setup. In the past I tried many launching rpms but settled on 3000 to 3500. I always lift. Usually shift around 6000 to 6500. It depends on the setup, tires, and gearing I have at the time. One setup hit the rev limiter in 3rd right before the stripe and the limiter was at 7100rpm. That was 29" tires with 3.55 gears iirc. Fastest trap speed was with a whipple at 127mph.

Anyway I'm not a racer, just a test n tune guy going fast legally.

 

[DiMora]

I also killed an RST. It was due to using an OEM flywheel (poor mating with friction area of inner disc) and uneven heat build-up while drag racing.

I now use a McLeod RXT and I drive the car the same with occasional drag racing. I use street tires and only launch at 2,000 RPM. I've had no issues so far. I would run an RXT again.

McLeod said the RXT can "recover" if burned / glazed...but the RST cannot.

 

[s8v4o]

Ok, thanks for clarifying the type of racing. So when racing do both of you guys do no lift shifts at 7,000 or higher?

Have you thought about installing a WOTBOX?

 

[Falkinman]

absolutely, I just haven't done it yet. Right now I shift just before redline and my factory rev limiter sort of acts like a WOT box when I shift

 

[AutoXRacer]

Have you thought about installing a WOTBOX?

DiMora uses one.

 

[AutoXRacer]

absolutely, I just haven't done it yet. Right now I shift just before redline and my factory rev limiter sort of acts like a WOT box when I shift

I have been warned not to bounce off the rev limiter in these cars.

When I used to race imports, I bounced all day off the rev limiter and never had issues.

But it seems like these cars (Mustangs) its not recommended. Hopefully someone can explain why the difference. I think its the way Ford has the limiter setup vs how imports do it.