Graziano Gearing and Drop Gears

I've finished 4 SL-C's with the new gears. Engines have been the 525 hp LS, 1200 hp twin turbo LS and 2 LT4's. Also have a LS 525 without the drop gears.
The gearing feels great with shift points feeling very natural.
First gear is now usable without sacrificing the acceleration when needed.
I always thought that the Ricardo transaxle gearing was too high and the Graziano stock gears too low. The new gearing finds a great balance between the two.
Did any of the cases need to be modified forr the new 1.04 gearing
or is it true drop in?
 

Ken Roberts

Supporter
John B at HFC Autosport, what are the actual ratios of the V10 graziano (for drop gear calculating)?

06 and up Gallardo V10 and Audi V10
Effective........... Actual
1-4.37................. 1-3.311
2-2.71................. 2-2.053
3-1.93................. 3-1.462
4-1.50................. 4-1.136
5-1.24.................. 5-.939
6-1.04.................. 6-.788

transfer-1.32
Final drive-3.08
 
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Did any of the cases need to be modified forr the new 1.04 gearing
or is it true drop in?
Paul - the case needs a small amount of machining. We generally work with Ron McCall (McCall's Autoworks) on these. He's done about a dozen now - great feedback from customers.

John B at HFC Autosport, what are the actual ratios of the V10 graziano (for drop gear calculating)?

06 and up Gallardo V10 and Audi V10
Effective........... Actual
1-4.37................. 1-3.311
2-2.71................. 2-2.053
3-1.93................. 3-1.462
4-1.50................. 4-1.136
5-1.24.................. 5-.939
6-1.04.................. 6-.788

transfer-1.32
Final drive-3.08
Ken - those ratios are correct out to the thousanths. I'd use with confidence.
 

Johan

GT40s Supporter
FYI, I didn’t need any clearncing/grinding when installed into a KVJ (R8 V10) That was with the 1,04:1 gear
 
Ken - Johan has our drop gears. Two sets, actually!

Johan - I'm a little concerned about your installer not clearancing the boss. There have been 15+ sets installed now, and all I'm aware of required some machining. It's a lot more with the .76's, but the 1.04's need some as well.
When you do the second set, will you please double check that area? My gut tells me the first one is going to have to come apart.
 

Johan

GT40s Supporter
Hi John,
I was totally prepared for some clearencing when we istalled your transfer gear, but as it turned out it was not nessesary.
After your post here I called my friend doing the gear change and he is as certain as I am it was not needed.
Just to be certain I went out to my garage and checked it. When turning the input shaft when in gear (1 through 6) there is no resistance nor any strange noice.
Can’t remember now, but I believe we had about 1-1,5mm clearance to the casing.

This is an older transaxle (KVJ) so I wonder if the casting is a little different?
This will also explain the recessed gear. (You said they changed around 2014)
 

Ken Roberts

Supporter
I can confirm that my V10 Graziano (KVJ) also did not need to have a clearance machined in the case for the HCF 1.04 drop gears. Heffner Performance in Florida performed the install.
 
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I stand corrected! Pulled the trans product guide and there is, in fact, a different part number for that particular housing. Very possible there's a difference in the casting that makes the 1.04's (but not the .76) not need any additional clearance.

Thanks Ken / Johan!
 
Installing the Drop Gears...

I bought a set of John's gears a while back and put them in this week. I posted about this on the FB group ("Superlite SL-C Owners & Builders" for any Owners or Builders that want to join). Figured I'd include my comments and thoughts here since a lot more will probably see it here (hopefully without my phone typos).

My trans is a V10 unit. There is LOTs of clearance for these gears in the V10 case - no machining is necessary. V8 guys, YMMV. Pictures shows where these gears sit in the case to demonstrate.

If you do it yourself, expect 8 hours once you have it drained and on the bench if you really take your time. You will need 32/34/36mm sockets, some drifts/punches and one special tool (Audi T40210) or you can make one. I welded one up, but you could probably grind one out of the correct sized impact socket. You will also WANT a real 1/2" drive impact to remove the shaft nuts. And you will need a couple short 2x4 blocks or something to sit the trans on since the input shaft sticks out. If you are pulling the front drive, you need E-ring pliers and something to plug the hole.

You don't need the rest of the special tools in the manual and you do not have to disassemble the gear stack. The gear stack is heavy, so you may or may not need a hand lifting it out and putting it back in (the manual shows a special plate and a shop crane, but I did it by hand by myself with no issue).

I did not start with the manual, but did pause when I got to the point where you have to get the pinion out. Found the manual (attached here), and sure enough, you have to beat it out. The manual is not ideal because it covers way more than what you want, and has no complete parts picture for the trans. But all you need is there as long as you take pictures as you disassemble, or lay the parts out methodically.

A comment on John's gears...

I don’t know John other than buying the gears from him and I’m not a mechanical engineer. But we have been racing for a long time and do most our own work, so I've seen plenty. Given that background, take this however you want...

The OEM gears are such that at times only one tooth is taking the pressure. John’s are the same. However, John’s gears have a heavier root and a shape that keeps the tooth thicker until the next tooth engages. IMHO, materials and hardening being the same, I believe John’s gears are stronger. Given the fit and finish is miles better than OEM, likely the material and hardening surpasses OEM as well.

I've include pictures of both sets of gears together. You can see the tooth shape and size, as well as the rough edges (failures waiting to happen) on the OEM gears and the much better finish of John's. John's gears also fit better on the shafts - that is they were tighter but still went on by hand.

The attached pictures are LARGE so that folks can see the details on the gears.

I am going to try to attach the manual, but not sure it will let me as it's 11MB and it's a PDF

Frank

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Fit in case

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Old vs New

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Attachments

Had the SLC out today. First time with the new drop gears.

Before I’ve had an LS7 and LS1 in the car. Now I have a 1UZ with a large turbo. This motor is only 244cid so MUCH less torque than an LS.

1st is WONDERFUL!

Before, I’d start in 2nd. In fact I generally shifted 2-4-6 and just used only those gears.

Now shifting through all the gears is just right. With the car so light, I can still lug it down to 800rpm in 6th. Still just lights the tires up if taking off aggressively in 1st.

On track (TMS Infield), I only used 3rd gear once up to speed. If I was more comfortable on that track, I would have been using 4th on the front straight and 3rd on the remainder.
 
Many thanks for the review, Frank! I'm glad you're happy with the gears and they've proven to be a good match for your use. That type of road course driving is exactly what the 1.04's were designed for!
 
By the way, we offer transfer gear sets in a 1.04, 0.90 and .76 ratio depending on your intended use.

The ideal match for a street/road course car is the 1.04 combined with an overdrive 6th gear (which we are waiting on a part from Graziano to finalize). For those willing to sacrifice some acceleration, the .90s offer a similar overdrive rpm in 6th for the highway; the trade-off is some acceleration in gears 1-5 and a first gear that's a little on the tall side for clutch life/smooth engagement.
 
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