SPEC Clutches Interest?

Brian Hamilton

I'm on the verge of touching myself inappropriatel
Hey guys,
I work for a performance shop in Austin, TX called Motion Dynamics. I used to work here years ago and left to persue other employment and now I'm back. Haha Long story. Anyway, I'm doing all the marketing & sales here and was thinking that I could put a little something together for the GT40 guys. We are a SPEC Clutches dealer and I'd like to put together a group purchase. The only thing I really need is motor & transmission information in order for them to prepare a clutch for it. Is this something that would be of interest? If so, please reply with your drivetrain information and I'll see what I can get together.

Thanks in advance everyone,

Brian
 

Randy V

Admin
Lifetime Supporter
How about a clutch/pressure plate that will work with a Porsche G50 and a small block Ford?
 

Lynn Larsen

Lynn Larsen
If you really want to provide a useful clutch to the GT40 (and other midengine component cars) community that differentiates your company from all of the rest, then I would suggest the following:

Provide a twin disk clutch that provides high (total) clamping forces with minimal release exertion in a diameter that will fit a wide range of flywheel dimensions. I would also suggest that you give serious consideration to providing an annular hydraulic release mechanism with all clutches. I think that the following list defines a reasonable priority order for fitment:

Porsche G50 family
Porsche 930
ZF 5DS 25/RBT 5spd
Audi

Other transaxles could be supported as they become available and demand increases. There are a limited number of businesses that supply adapter kits for a variety of Ford engines and these transaxles. One could design the clutch covers to fit the flywheel bolt pattern of the adapters these companies make and/or the flywheel bolt pattern on engines that these transaxles attached to in the "stock" situation. It would probably be reasonable to consider also supplying flywheels for Ford small blocks, big blocks and modular engines, which are the heart of an adapter kit. The drawback is then having to provide these for internally or the various flavors of externally balanced engine setups.

Regards,
Lynn
 

Brian Hamilton

I'm on the verge of touching myself inappropriatel
Lynn,
Thanks for all the input! The company that we work with makes custom clutches for just about anything. They build them in house so they can put any spline and diameter center section on any friction disc & pressure plate they want and it all works beautifully. We have done quite a few custom ones for the vehicles we build in our shop. They have also just come out with a Ford dual disc clutch setup that I'm pretty sure I can get made to work with any transmission because, like I said, they just have to swap out the center hub. Right now I'm just trying to gauge interest and see what kinds of combinations that people want to have a clutch for. I already have a few PM's and would like to get some more. Hehe I have to see what kind of interest level there is and then what kind of price break I can share with you guys. I'm going to call them today and talk about the transaxles you mentioned and see what they have for me. There are also hybrid clutches they build that have a higher clamping force but not much pedal effort. I have sold MANY of these to our Mustang clients and they all love them for daily street use and it still holds the 500-700+ ft. lbs. they are putting through the rear tires. Keep the interest coming!!!

Brian
 

Brian Hamilton

I'm on the verge of touching myself inappropriatel
OK
I just got off the phone with SPEC and they said there is absolutely NO PROBLEM making clutches for whatever you guys need. Here's a pretty good idea what kind of power they will handle...

Stage 1 - 410 ft. lbs
Stage 2 - 520 ft. lbs.
Stage 2+ - 620 ft. lbs.
Stage 3 - 680 ft. lbs.
Stage 3F - 800 ft. lbs.
Stage 4 - 680 ft. lbs.
Stage 5 - 1100 ft. lbs.

Here's a brief Stage description also...
Stage 1 -
Types of Driving: Street, Drag, Drift, Road Race, Rallye, Pulling, Autocross

For bolt on naturally aspirated and mildly modified forced induction engines. Stock-like daily drivability and very good wear characteristics.

High clamp pressure plate, steel-backed and multi-compound woven organic material and high torque sprung hub and disc assembly, bearing and tool kit.


Stage 2 -
Types of Driving: Street, Drag, Pulling, Autocross

For all mild to moderately modified naturally aspirated and power adder engines. (Also good for stock power levels and spririted driving when good daily drivability and extremely long life are the goal.) Stock-like daily drivability and EXCELLENT wear characteristics.

High clamp pressure plate, pure Kevlar friction material and high torque sprung hub and disc assembly, bearing and tool kit.


Stage 2+ -
Types of Driving: Street, Drag, Road Race, Rallye, Pulling, Autocross

For all modified engines making more torque than the stage 2 can support. Maintains stage 2 feel for good daily drivability and offers very good wear characteristics, but provides a higher torque capacity. High clamp pressure plate, composite multi-friction carbon-kevlar material, high torque sprung hub and disc assembly, bearing and tool kit.


Stage 3 -
Types of Driving: Street, Drag, Drift, Road Race, Rallye, Pulling, Autocross

For heavily modified street and race engines. Offers sufficient daily drivability with a comfortable pedal feel and quick engagement. Offers good wear characteristics under low and high stress usage.

High clamp pressure plate, 4 or 6 puck carbon semi-metallic friction with high torque sprung hub and disc assembly, bearing and tool kit. 6 puck is standard on most applications, but 4 puck can be specified when ordering.


Stage 3F -
Types of Driving: Street, Drag, Drift, Road Race, Pulling

For heavily modified street and race engines making more torque than the st3 can support. Offers good daily drivability and better manageability than the stage 3, with even better wear characteristics.

High clamp pressure plate, full-faced carbon metallic friction, high torque sprung hub and disc assembly, bearing and tool kit.


Stage 4 -
Types of Driving: Drag, Drift, Road Race, Rallye, Pulling, Circle Track

For heavily modified engines or engines of any modification level being used in the above driving environments, where an instantaneous engagement and light weight are beneficial. Not street-friendly due to harsh engagement.

High clamp pressure plate, 3,4 or 6 puck carbon semi-metallic friction with high torque rigid hub and carrier assembly, bearing and tool kit.


Stage 5 -
Types of Driving: Drag, Pulling

For extremely modified drag race and pulling engines, or applications that call for a ‘slipper’ clutch/progressive torque-induced engagement. These clutches are best ordered as custom configured and should be ordered after providing specific information about the car and it’s purpose to a SPEC technical assistant. Not street-friendly due to harsh engagement.

High clamp pressure plate (adjustability available on some applications), rigid iron disc assembly, bearing and tool kit.



There are also aluminum flywheels & steel flywheels are available for 302's & 351's. Again, I would like to get interes levels before I start quoting prices. Know what I mean?

Laters,

Brian
 
Brian,

I think Lynn makes some excellent suggestions. A standard clutch pack assembly that can easily be adapted to a wide range of transaxle combinations would be an advantage. A reasonably small dual disc would really help keep pedal pressures to a reasonable level; a common complaint. The down side of multi disc clutches is their abruptness, so you normally lose any sense of modulation. Though not an issue for a track car, it makes for difficult smooth launching on the street. It would be nice if a Marcel spring could be emplyoyed, but I suspect it would create too much axial travel in a dual disc configuration. Perhaps your clutch manufacturer can engineer something sutable with the right combination of friction materials and mechanical components in a dual disc configuration.

Andy
 
Brian, please don't forget there are many GT40's using the Renault UN-1. There are a few of us in the U.S. and many more in the UK. Many use the AP racing clutches available. These hold well but I think they are a little weak in the daily driver dept. This box is also used in Lotus Esprit and DeLorean appplications.
 

Russ Noble

GT40s Supporter
Lifetime Supporter
Lynn,
Thanks for all the input! The company that we work with makes custom clutches for just about anything. They build them in house so they can put any spline and diameter center section on any friction disc & pressure plate they want and it all works beautifully. We have done quite a few custom ones for the vehicles we build in our shop. They have also just come out with a Ford dual disc clutch setup that I'm pretty sure I can get made to work with any transmission because, like I said, they just have to swap out the center hub.
Brian

There's a wee bit more to it than that Brian. The diameter of the flywheel has to fit inside the bellhousing!

In the case of the G50/930 application, the bellhousing ID is 280mm (approx 11") This means most use the stupid and heavy Porsche type flywheel and use the rear trans mounted Porsche factory starter position. IMHO the better option, mount the starter in a new position on the adaptor plate to suit the small ring gear, and you can use a conventional lightweight flywheel. This may entail minor oil pan mods to clear the starter. This would then work for all trans, the only difference being the individual trans bolt pattern on the adaptor and the clutch splines etc.

The other way is to have two kits. One for Porsche type setups and another for 'rest of the world'!

From my own experience I also disagree with the statements made elsewhere that sintered bronze multiplate clutches are harsh and unprogressive. When using a concentric hydraulic release bearing which effectively has no pivot friction or lever flex, I have found these to be well modulated and easy to use. Maybe it's all in the release setup?

Cheers
 
Brian, Ditto on what 40 Bud said,,,,,,as I mentioned this morning (when we talked), there are lots of us here in US that have the UN1/Ford Setup with 151 Tooth ring gear.

Cheers
 

Brian Hamilton

I'm on the verge of touching myself inappropriatel
Looks like we have a huge variety to work with here. Haha OK, so it looks like what I need to know from everyone is flywheel diameter, engine, and transaxle. I did speak with SPEC and they said the Renault transaxle isn't a problem either. Like I said, they can do anything for anything. This is just to gauge interest in who would like to participate in a group purchase. Once I get a raw number then I get to find out what kind of price break I get and then I can give you guys all prices for the individual setups. Looks like there are going to be fery few, if any, one-off's so that's great. I talked to Iron Shiek today on the phone about his setup with the Renault transaxle and he informed me that there were a few guys within minutes of him running the exact same setup as him, so there are multiples of any configuration. The company who produces these clutches, SPEC Clutches, prides themselves on being able to build anything to suit the customer. Different diameters with stronger pressure plates and all that isn't going to be an issue from what they're telling me. As long as I have accurate information from the end user on what the desire and what they are running, we shouldn't have any issue at all. rockonsmile If you want, feel free to give me a call at the shop and I'll answer any questions you want.

Laters,

Brian
512-670-2271 (shop)
 
Last edited:
Brian, please don't forget there are many GT40's using the Renault UN-1. There are a few of us in the U.S. and many more in the UK. Many use the AP racing clutches available. These hold well but I think they are a little weak in the daily driver dept. This box is also used in Lotus Esprit and DeLorean appplications.
I Use those, and AP Racing is walking distance from my house :D . Retail at about £200GBP for a 4-Paddle cerametallic friction plate, re-conditionable for about £60GBP. Last on average 10,000 miles on a Turbo 4wd doing the 'odd' full throttle launch.
 
Dave, I know lots of AP's are in use. My question is how are they for daily driving in traffic and driving onto a trailer? The paddle and multi disc units I have run across are usually a little on the grabby side and either on, or off and not very slippable.
 
Looks like we have a huge variety to work with here. Haha OK, so it looks like what I need to know from everyone is flywheel diameter, engine, and transaxle. I did speak with SPEC and they said the Renault transaxle isn't a problem either. Like I said, they can do anything for anything. This is just to gauge interest in who would like to participate in a group purchase. Once I get a raw number then I get to find out what kind of price break I get and then I can give you guys all prices for the individual setups. Looks like there are going to be fery few, if any, one-off's so that's great. I talked to Iron Shiek today on the phone about his setup with the Renault transaxle and he informed me that there were a few guys within minutes of him running the exact same setup as him, so there are multiples of any configuration. The company who produces these clutches, SPEC Clutches, prides themselves on being able to build anything to suit the customer. Different diameters with stronger pressure plates and all that isn't going to be an issue from what they're telling me. As long as I have accurate information from the end user on what the desire and what they are running, we shouldn't have any issue at all. rockonsmile If you want, feel free to give me a call at the shop and I'll answer any questions you want.

Laters,

Brian
512-670-2271 (shop)
Not that we get robbed here in the UK for everything, (well, we do. Gas is about $9 a gallon :eek: ) but could you guesstimate a price for a stage 1 clutch cover and friction plate for my application? I Use a Renault UN1 Transaxle, mated to a J-Series Renault block. Friction plate is 228mm dia. I'm not shy about adapting my flywheel to your cover, I'd say the cover extends to about 240mm dia and fixes to the fly with 3 pairs of 6mm allen head bolts.

Group buy is very plausible as availability is minimal over here, save the AP 4-paddle friction plate there is nothing available, with the std cover the AP friction plate will hold about 320lb/ft. Not enough!

Thanks in advance!
 
Everyone!

Safir GT40 Spares, Limited is just completing its first batch of components for our clutch/flywheel/ring gear/ bell housing assembly which will mate a small block Ford to an RBT/ZF gearbox.

The original cars used a small flywheel and ring gear, no portion of which hangs below the lowest chassis point. Many people today are using the larger 157 tooth ring gear and 11.5"+ flywheel, and the bottom of the bell housing hangs below the chassis about 1.25". If the road kill is anything but a snake, it will find its way into the clutch. Being the lowest point of the car, any bottoming out situations will be hard on the components.

Safir is offering genuine GT40 brand parts, with an 8.5" diameter twin disk, organic plate clutch (the same used in the Saleen S-7) good for over 800 ft-#s of torque, the small flywheel and ring gear, and the original style bellhousing with the two cast bosses to locate the assembly to the bottom cross menber of the frame. The package works well with the high torque Tilton or similar starter. The bell housing can be machined for mounting the external clutch slave cylinder, or drilled for a hydraulic throw out bearing.

Please give us a call!

Bob Wood 513-672-8105 days, 513-831-5628 evenings
Brady Pack
John Sadler 403-238-2246
 
Dave, I know lots of AP's are in use. My question is how are they for daily driving in traffic and driving onto a trailer? The paddle and multi disc units I have run across are usually a little on the grabby side and either on, or off and not very slippable.
Depends what you call grabby. I'd happily use it anytime, but, to put it in context, my Mrs would get straight out the car with a frown on her mush "i'm not driving that thing if you think I am" stylee.
Judder- Yes, at lower RPM. Raise it over 2K and is more a vibration.
Harsh- Yes, I suppose. More forgiving than most though with a std Renault/Valeo cover plate.

We do use one in this track car of ours and have NO problem on and off the trailer even with a lightened flywheel......


 

Lynn Larsen

Lynn Larsen
I also disagree with the statements made elsewhere that sintered bronze multiplate clutches are harsh and unprogressive. When using a concentric hydraulic release bearing which effectively has no pivot friction or lever flex, I have found these to be well modulated and easy to use. Maybe it's all in the release setup?
Thank you, Russ. That's part of the reason for the recommendation to provide "an annular hydraulic release mechanism with all clutches." It is not difficult to design progressive engagement into a multidisc clutch as well. (I have worked on two stage, multidisc clutches where one plate operated a p.t.o. (1st stage) and the other propelled the vehicle through a single clutch pedal.)

Another reason for the recommendation is that it would open up the use of a wider range of transaxles. My guess is that, as time goes along, more and more people will start to consider more conservative power plants in order to achieve better fuel mileage while having very minimal impact on the "fun factor" of owning and driving a GT40. This would make the plentiful 915 a very viable transaxle. This would be especially true if a simple to implement and reasonably priced hydraulic clutch mechanism were available.

Regards,
Lynn
 
Not to be rude, but...............

I remember reading somewhere if a person/company sells goods or services to members, that person/company should consider becoming a Supporting Vendor, Yes/No?

I can see the benifit that Brian Hamilton / Motion Dynamics has to offer the members on this forum. But I think Ron is trying to direct this forum in a way where the forum also benifits.

Let it fly,



Just an observation that I wanted to pass on to you all.
 

Brian Hamilton

I'm on the verge of touching myself inappropriatel
Not to be rude, but...............

I remember reading somewhere if a person/company sells goods or services to members, that person/company should consider becoming a Supporting Vendor, Yes/No?

I can see the benifit that Brian Hamilton / Motion Dynamics has to offer the members on this forum. But I think Ron is trying to direct this forum in a way where the forum also benifits.

Let it fly,



Just an observation that I wanted to pass on to you all.

ABSOLUTELY!!!
It's not my intention to just do a "free blast" or anything like that at all. What I'm trying to do right now is gauge interest and go from there. Once (and if) we decide to make it a go, then by all means we will become a supporter of the site. No problem with that. Ron & I have PM'd each other about just that. I'm not trying to get anything free but information, trust me I would not like to put a bad vibe in this community about either my shop or myself. I like you guys!!!! That's why I'm trying to help however I can.

Thanks,

Brian
 
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