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Old 18th April 2017, 12:04 AM   #1
JBurer
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Graziano Gearing and Drop Gears

I put this post together to help others avoid the pitfalls I've encountered with my Graziano L140 - transaxle from the Ausdi R8, Lamborghini Gallardo and some others. There's a huge amount of misinformation out there about gear ratios (including Audi's own product guides) and all aspects of a drop gear solution - in particular their impact on ratios/engine rpm and ease of install.

This post has been over a year in the making - starting with when I ordered my 2014 R8 Gearbox (Audi code: KBA). Shortly after it arrived I realized the gearing in it didn't match Audi's published materials. What was supposed to be just a nuance of my Superlite Coupe project took on a life of its own. Getting to the answer wound up involving more effort than I'd like to admit - hours and hours of research, conversations with the Audi Executive responsible for the R8's launch, more conversations with the lead engineer in Germany and ultimately installing a set of drop gears on my transaxle and driving the car.

In short - there's a transfer gear in the transaxle. It's the gear set the drop gears replace and it has a ratio of 1.32.

Audi materials don't disclose this gear, and Audi represents different ratios in its early product guides than it does in its later product guides. This was news to the folks at Audi when I brought it to their attention.

In short - the ratios represented in the early materials are effective gear ratios; they incorporate the transfer gear ratio into the number shown. The later materials represent the ratios of the actual gears themselves and make no mention of the transfer gear. For the purpose of swapping gears, it makes sense to work from the actual ratios. For simplicity, for the V-8 version of the R8 Graziano, they are:

1st - 3.31
2nd - 2.05
3rd - 1.42
4th - 1.07
5th - 0.85
6th - 0.7
Transfer - 1.32

What this produces is great for the low torque, high revving Audi motor - not so much for the LS motors, particularly for street use where 1st gear is far too short (37mph) and 6th gear has you sitting at about 3400rpms on the highway at 80mph. I've attached a gearing model to this post for my car showing rpm and speed for each gear.

The solution available thus far has been to swap for a .76 ratio transfer gear. It's been advertised this drop gear:

1. will produce about a 240mph top speed,
2. highway cruise at 2500rpms
3. is an easy, 30 minute install once the gearbox is apart

I bought one of these gear sets, had them installed by a well-respected Ferrari shop familiar with Grazianos and learned the hard way this is all wrong. During install, I learned changing the transfer gears require the entire gearbox to come apart, every gear to come off the shafts and a portion of the case to be machined - hardly a 30 minute job. After driving the car (I believe mine is the first set actually installed and in a car that's been driven) I realized the impact of the .76 drop gear is much greater than advertised. Try a 302mph top end and highway cruise at 1800rpms. Gearing model attached.

Now these gears aren't all bad; they're actually just slightly taller than the factory Ricardo gearing. For someone building a high horsepower car, or one they want to have similar gearing to that of a production Corvette, they are great - but they're not what's being advertised on any level. I've learned subsequently this 0.76 ratio set was developed for the 1,000hp+ Twin Turbo Gallardo guys who wanted to run the Texas Mile. With a higher horsepower car or that type of application, this set is a good fit.

For me, though, with the 525hp LS376 motor in a car I plan to drive on road courses and on the street, it's not such a great fit. When I drove the car with the .76 gears the gearing felt too tall - acceleration didn't impress with my horsepower level and 6th gear became unusable. To match what I was looking for I needed something closer to a 1.038 ratio... so I commissioned having them made. They produce what the other gear was originally advertised to do - the 2500rpm highway cruise, a reasonable 1st gear (47mph) and a 221mph top speed. Gearing model attached.

I plan to offer these to the community and have a run of 10 of the 1.038 ratio drop gears being manufactured. The gears will cost $1,700 with a run of 10 and possibly less if there are more orders. Six are spoken for as of now, and I can increase the order size in the next few weeks if there is demand for them. If not, this is not an item that will be stocked - it'll require sufficient interest to make another run of them. I can also source the 0.76 gears, if that is a better fit for your application, for the same price.

Recognizing there isn't a great avenue for installation, I've arranged for the same shop who installed my drop gears to install them for others, if desired. I am friendly with the shop and have other projects with them ongoing, but have no financial interest in the install of the gears.

Welcome to reply here or to reach me at hcfparts at gmail to indicate interest in the gears. I plan to take a $500 deposit once I know what the final order will be. I'll loop you in with the installer separately to discuss shipping, turnaround time and payment for the gear install directly.


Best,
John

Attached Thumbnails
Graziano Gearing and Drop Gears-76-gears-jpg   Graziano Gearing and Drop Gears-gear-install-3-jpg   Graziano Gearing and Drop Gears-gear-install-2-jpg   Graziano Gearing and Drop Gears-gear-install-1-jpg  
Attached Files
File Type: xls Gear calculator Graz V8 - .76 gears.xls (36.0 KB, 123 views)
File Type: xls Gear calculator Graz V8 - 1.038.xls (36.0 KB, 126 views)
File Type: xls Gear calculator Graz V8 - OEM.xls (36.0 KB, 115 views)

Last edited by JBurer; 30th April 2018 at 08:55 AM.
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Old 18th April 2017, 05:04 AM   #2
Cam
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Re: Graziano Gearing and Drop Gears

Great summary John! I went through a similar path except stopped short of having my gear box updated. I had been working with an individual to PURCHASE the "special" Graz gearbox with ideal gearing but opted not to once I dug in further and discovered this box did not actually exist (despite assurances it did and that they had one in their possession). That took me down the path of the same gear set you installed and frankly I am pretty upset the gears advertised are flat out wrong. I would be super pissed had I gone through with the installation only to find my car was even further in the wrong direction than where I was trying to take it.

A quick search for graziano and drop gears will reveal who it is I was speaking with. I know there are others here who have dealt with this individual and I would urge you to discuss John's post above and get direct responses to the things John has discovered. Unless you are intending to build a super high horsepower/top speed car, expect your gear box to be unusable if you go through with his drop gear update.

Full disclosure, I am one of the folks signed up for John's drop gears and I plan to go through Brian for my gear install.
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Old 18th April 2017, 11:16 AM   #3
Ed Davis
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Re: Graziano Gearing and Drop Gears

John
Thanks for the work. Keep me informed on the time line.

Ed
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Old 18th April 2017, 12:08 PM   #4
EFNFAST
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Re: Graziano Gearing and Drop Gears

ya'll should just use a 930 .... real men don't need more than 4 gears
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Old 18th April 2017, 06:43 PM   #5
JBurer
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Re: Graziano Gearing and Drop Gears

By the way, some information on the gears themselves. They'll be made of a aircraft quality alloy, cut, heat treated and given a ground tooth finish. Tolerances are two ten-thousandths of an inch. I'll have stats on runout before they're made. The comparison to the raw cut gears in a Quaife transaxle, with looser tolerances and no ground finish on the gear teeth, is noteworthy.

The .76 gears, which are made the same way, have been used in 1,000+ hp Turbo Gallardos with much more weight and under higher stress scenarios with no failures. I don't have any reservations about putting a set in my 550hp SLC.


Quote:
Originally Posted by Ed Davis View Post
John
Thanks for the work. Keep me informed on the time line.

Ed
Hi Ed - we're looking at a 90 day window assuming I find at least 10 buyers. Potentially sooner if I find the buyers sooner!


Quote:
Originally Posted by EFNFAST View Post
ya'll should just use a 930 .... real men don't need more than 4 gears
Sounds like gear envy to me ;-)



Quote:
Originally Posted by CamT View Post
Great summary John! I went through a similar path except stopped short of having my gear box updated. I had been working with an individual to PURCHASE the "special" Graz gearbox with ideal gearing but opted not to once I dug in further and discovered this box did not actually exist (despite assurances it did and that they had one in their possession). That took me down the path of the same gear set you installed and frankly I am pretty upset the gears advertised are flat out wrong. I would be super pissed had I gone through with the installation only to find my car was even further in the wrong direction than where I was trying to take it.

A quick search for graziano and drop gears will reveal who it is I was speaking with. I know there are others here who have dealt with this individual and I would urge you to discuss John's post above and get direct responses to the things John has discovered. Unless you are intending to build a super high horsepower/top speed car, expect your gear box to be unusable if you go through with his drop gear update.

Full disclosure, I am one of the folks signed up for John's drop gears and I plan to go through Brian for my gear install.

Thanks Cam - it's been a long road!!
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Old 18th April 2017, 09:45 PM   #6
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Re: Graziano Gearing and Drop Gears

Quote:
Originally Posted by JBurer View Post

Sounds like gear envy to me ;-)

pffft, I've never used a gear higher than 4th in my Ricardo
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Old 22nd April 2017, 12:38 PM   #7
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Re: Graziano Gearing and Drop Gears

I'm in.... I will pm you for info
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Old 23rd April 2017, 10:46 AM   #8
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Re: Graziano Gearing and Drop Gears

Quote:
Originally Posted by mcfling View Post
I'm in.... I will pm you for info
I also am in! I have PM'd you John.


cheers,

Craig
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Old 25th April 2017, 06:46 PM   #9
JBurer
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Re: Graziano Gearing and Drop Gears

Thanks everybody!

We have the minimum number of orders in hand and kicking off production. If anyone wants in on the gears, there's probably another 1-2 weeks where I can increase the order size. Past that and we'll need to wait for enough interest to do another run.
Best,
John
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Old 6th May 2017, 06:55 AM   #10
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Re: Graziano Gearing and Drop Gears

Read with extreme interest the discussion (john has done some homework here) on the Graz gearing and its impact on the car mated to an LS3/480. I think it goes without question the OEM gears are not the best for the HP/Torque specs of the LS engine. Based on the chart pictured below, I made a choice on which transfer gear set to change to, so here is my reasoning. There seems to be a 70/30 split on the 1.038 set versus the .76 gears and as usual I find myself in the minority. I found and built my own RPM vs Speed tables based on the engineering formulas included in the picture and used my C6 Corvette Z-51 gears and speed as my baseline. While the 1.038 gears set imitates the Corvette best gears 1-4, the tipping point for me was the cruising RPM at interstate speeds………at 80, the Corvette RPM is 2000. With the .76 the SLC it will be ~1800, and with the 1.038 ~2500. The Vette weighs in at nearly 3400 lbs with an LS2 (400hp/400 ft lbs). I expect the SLC to be around 2700-2800 lbs when finished with 480 HP and 480 ft lbs. I am not building a dedicated track car (too expensive if I wreck it), so this is a street cruiser. I know some builders have already tried the .76 gears and are not impressed with the acceleration, so I hope my choice doesn’t prove to be a disappointing decision.

I ordered the gears, but haven't installed them, so if I'm way off track here, flag me off now......
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Old 27th May 2017, 04:50 PM   #11
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Re: Graziano Gearing and Drop Gears

Hi John:
Thanks for sharing all of this. Someone mentioned that you might have used the Audi R8 shifter in an SLC. I am considering that option. Do you have any information or feedback on that?
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Old 27th May 2017, 10:10 PM   #12
JBurer
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Re: Graziano Gearing and Drop Gears

Quote:
Originally Posted by mksetter View Post
Hi John:
Thanks for sharing all of this. Someone mentioned that you might have used the Audi R8 shifter in an SLC. I am considering that option. Do you have any information or feedback on that?
Hi Mark - it works great. Shoot me an email at jburer t yahoo and I'll share a video of me driving the car
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Old 12th June 2017, 04:30 PM   #13
Ed Davis
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Re: Graziano Gearing and Drop Gears

Anything new on the gears
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Old 12th June 2017, 05:49 PM   #14
JBurer
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Re: Graziano Gearing and Drop Gears

Quote:
Originally Posted by Ed Davis View Post
Anything new on the gears
Hi Ed,

I spoke to the owner of the shop manufacturing these about 10 days ago. He said they were going into production "soon".

The original time estimate (and the follow-up message I sent on May 16th) put us as late as the end of July. I'll be in touch as soon as I know more - likely with the gears in hand.

My wife and I are having another baby at the end of this month - so if I'm delayed in getting back to you please hang in with me.

Best,
John
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Old 13th June 2017, 11:38 AM   #15
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Re: Graziano Gearing and Drop Gears

Congratulations
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Old 14th June 2017, 06:43 PM   #16
Dan carter
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Re: Graziano Gearing and Drop Gears

Congrats to John and his wife.fficeffice" />

I cleared it with John to share this info with the forum. I have been on the hunt for other install options for the Graz conversion. I have two additional to share with you if you wish to pursue. 1. MTI racing in Atlanta Georgia and 2. Audi Sport Customer Racing. I have personally used MTI for my Corvette and they do good work. While attending the Pirelli World Cup at VIR, I ran into the Audi race team and talked to their head mechanic Charlie about our Graz conversion and they have expressed an interest in helping. So here is their contact info.

Option 1.
MTI Racing/Machine has 25 years of experience in Auto Racing and Mechanical Engineering. MTI Machine makes single components or can fabricate entire assemblies. They offer: Designing, Prototyping, Machine building, Fixtures, Short run productions, General tooling, & Assembly.

They have CNC milling, turning, grinding, and multi-axis 3D machining tooling. Our highly trained engineers, CNC programmers, and machinists are uniquely innovative, awesome, and maintain an unmatched attention to detail.

Call Reese, Nick or Chris 770-919-7774

Option 2

Well we are the home of Audi Sport Customer racing since its introduction in 2012. Brad Kettler is a Multi time LMP1 wining engineer and crew chief. Charlie Boggs is the only factory trained gearbox and engine tech in the USA for both generations of Audi R8LMS's. The internal names are GT3-017 and GT3-038. Charlie has personally done over 300 Audi races boxes. The shop is outfitted with all the needed tools including a full size ultrasonic cleaner. They are set up for exactly this kind of work. They have a small staff so it's easy to get in touch with them.

Charlie Boggs Head Mechanic
Audi Sport customer racing
Phone: 1-513-280-6080
Mobile: 1-513-720-5134
email: [email protected]



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Old 14th June 2017, 09:31 PM   #17
Cam
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Re: Graziano Gearing and Drop Gears

Very cool Dan! Do you have pricing info for these shops? Of the two Audi Sport seems like the place to go but when I see pro level support that typically means $$$.
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Old 14th June 2017, 10:53 PM   #18
Dan carter
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Re: Graziano Gearing and Drop Gears

I don't have a fixed price, but Charlie estimated about 2k. Quantity could bring that down, but any negotiation needs to be direct with them.
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Old 15th June 2017, 10:55 AM   #19
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Re: Graziano Gearing and Drop Gears

Brad Kettler was chief when Champion Racing ran the Audi R8 LMP.
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Old 24th June 2017, 05:11 PM   #20
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Re: Graziano Gearing and Drop Gears

The 9310 alloy is in - we're in for production in the next week or two!

Partially finished gear sets (not ours) waiting for teeth to be cut and the final carburization/grinding process.
Best,
John
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