New transaxles for SLC?

[Fran Hall RCR]

Absolutely NOTHING is interchangeable...unless a transaxle is built specifically to meet every individuals personal preference there will always be a level of compromise...

I go out on a limb repeatedly to attempt to bring the best solutions to my customers but as the saying goes

"you can please all of the people some of the time and some of the people all of the time but never all of the people all of the time"

 

[TSR]

What does the weight scale say with these gearboxes?
also
Do there boxes come with launch control?

 

[TSR]

deleted

 

[Fran Hall RCR]

Tom,

I have not weighed the box, its a little academic really as I cant make it any lighter and for a box that will hold a 1000hp, it has to carry a certain amount of mass of material.

I will throw one on a scale this week though as I know its good info to have during a build but I expect it to be around 170-180lbs.

The box is a very similar length to a Ricardo GT trans, a touch longer actually but its not as large around the diff. area

There are also higher HP capable components available from these guys
Underground Racing - Transmission Upgrades

Launch control is an operation of electronics and engine management, nothing to do with the transaxle

 

[Nils Greger]

Weighed the Box , its approx 100kg incl. 4WD-Shaft and Oil-Cooler-Piping .

 

[Mike]

Absolutely NOTHING is interchangeable...unless a transaxle is built specifically to meet every individuals personal preference there will always be a level of compromise...

I go out on a limb repeatedly to attempt to bring the best solutions to my customers but as the saying goes

"you can please all of the people some of the time and some of the people all of the time but never all of the people all of the time"

Fran, if your products are pleasing 80% of the people I think you're doing just fine. Keep forging ahead - stagnant companies that do not change or bring new stuff to the table are the ones that slowly disappear. Just my opinion.

100kg equals about 220lbs.

 

[JD]

I go out on a limb repeatedly to attempt to bring the best solutions to my customers but as the saying goes

"you can please all of the people some of the time and some of the people all of the time but never all of the people all of the time"

True, Fran, but I for one, am very appreciative of your efforts to provide continuous improvements for your products. As we discussed the other day, selecting (and then finding) a reliable transaxle was a significant concern of mine. The SLC is a specialized vehicle when it comes to the drivetrain, much the same way the Lolas and other sports racers were in the 60's-70's. The drivetrain was a customer solution that needed to solved by the customer - sometimes with very poor results. You have taken another risk item off my list - Thank You!

 

[JD]

Gear-speed-tire-rpm figures -- pics attached

Mike (or Dave), is there any way that you can determine from your models what the rpm's are at 75 mph in 5th and 6th?

 

[Mike]

Mike (or Dave), is there any way that you can determine from your models what the rpm's are at 75 mph in 5th and 6th?

John -- PM me your email address and I'll send you the excel spread sheet calculator. You can then play with numbers.

 

[Dave]

Mike (or Dave), is there any way that you can determine from your models what the rpm's are at 75 mph in 5th and 6th?

Looks to be ~3400 rpm for 5th and ~2800 rpm for 6th

 

[Mike]

That is incredible, it appears Fan may have succeeded in finding the holy grail. High horsepower capable and reasonably priced.

The Mendeola SDR fits all your requirements.

Mendeola Transaxles, Inc.

 

[Chris]

Looks to be ~3400 rpm for 5th and ~2800 rpm for 6th

I realize this thread is old at this point, but I believe that RX-Heven was looking at the 70 MPH data rather than the requested 75 MPH data. Correct answer for 75 MPH should be ~3650 RPM for 5th and ~3030 RPM for 6th. Compare this to ~1600 RPM in 6th for the normal late-model Corvette Tremec setup.

I will continue to follow the Graziano threads, as I don't understand how these factory gear ratios are palatable to SLC owners that are (1) likely OCD by nature, and (2) spending $10K on a gearbox. The V8 Graziano's 2nd gear, according to my speadsheet, is shorter than the Tremec's 1st gear.

Not trying to disrespect the efforts of anyone involved; rather just trying to understand the compromises and final product. Perhaps I simply lack the appreciation of how starved folks have been for any durable transaxle package. I have seen rumors of a Graziano drop gear setup and will keep my eyes open for news on that front.

 

[P Roth]

Here is the company that makes them:
Home

 

[Will Campbell]

Here is the company that makes them:
Home

The gears are made elsewhere- Erik (at The Raceline) merely resells them. At least one local SLC has a set, but doesn't yet have them installed.

 

[James]

Would a .75 drop gear effectively reduce the ratio .75? Is the drop gear fitted outside the transaxle? I've asked in another forum, have not gotten a response.

 

[Will Campbell]

Would a .75 drop gear effectively reduce the ratio .75? Is the drop gear fitted outside the transaxle? I've asked in another forum, have not gotten a response.

The set for the Graziano is apparently fitted internally, near the diff end of the transaxle, requiring a pretty comprehensive disassembly and re-assembly. It's a lot more than just popping off the rear cover and swapping two gears, as it is with a Winters quick change, for example.

I don't know what the real gearing changes are, but when it is clear, I hope Tim T updates his excellent transaxle gearing spreadsheet with the info. Apparently the gears end up closer to the Ricardo.

 

[Chris]

I don't know what the real gearing changes are, but when it is clear, I hope Tim T updates his excellent transaxle gearing spreadsheet with the info. Apparently the gears end up closer to the Ricardo.

I've modified the latest gearing spreadsheet floating around to include the 0.7586 drop option (detailed by <a href="http://www.theraceline.net/the-race-line.html">these guys</a> on a thread on factoryfiveforum) applied to both the V8 and V10 Graziano boxes. I also included a late-model Covette Tremec ratio set for comparison since most people are looking at an LS engine. Included a redline of 6,600 RPM for the LS376. See columns N, P, Q in the attached.

The drop option looks nice. The factory Graziano ratios without the drop... not my favorite.

 

[Dave Nugent]

What's the cost for the drop gears?

$2,000


Worth it to have a ratio close to the Ricardo.

 

[Chris]

What's the cost for the drop gears?

$2,000


Worth it to have a ratio close to the Ricardo.

But that is reportedly just parts. I have yet to hear about install costs, but they are supposed to be significant given the complexity and requirement to disassemble the entire box. Anyone have the labor figure?

 

[Luke S]

Considering I just busted my GT2's transaxle on a little airport runway play, I'm intrigued before Fran finishes my setup.

 

[Les]

The linked article will clear up ALL confusion about transmissions!

A Tale of Two Porsche Seven-Speeds: Manual and PDK - Tech Dept. - Car and Driver

 

[Les]

Now, the article link I posted is not entirely for laughs. Porsche does have the same transmission casings and parts for the 991 911. It seems like this will help SL-C builders quite a bit, will it not?