Drop gears or not to drop gears?

Hey all,

Just put a down payment on my SLC build. Getting hung up on whether I should pay up front for drop gears or not. Fran is offering a pre-installed package with the Graziano and your choice of gearing, but at a cost of an additional $4k (install plus shipping both ways). Most of my driving would be cruising around town, not much highway driving. Would it be more enjoyable to leave stock gearing for this type of driving? Should I cough up the dough now or enjoy the stock gearing and worry about it down the road at a later time? Appreciate any input.
 
I bit the bullet and had it done up front. Nothing is more permanent than a temporary fix, so if you put it all together and it doesn’t work for you with stock gearing, imagine taking the car apart again and waiting however many months to get the work done, plus shipping. You might just leave it be and drive it slightly irritated. I’m pretty sure there are some folks who run the Graz stock, so they’ll need to chime in with their experiences, but if you’re considering having it done it’s better to do it without disassembling the car again. JMO.
 

Johan

Supporter
Hey all,

Just put a down payment on my SLC build. Getting hung up on whether I should pay up front for drop gears or not. Fran is offering a pre-installed package with the Graziano and your choice of gearing, but at a cost of an additional $4k (install plus shipping both ways). Most of my driving would be cruising around town, not much highway driving. Would it be more enjoyable to leave stock gearing for this type of driving? Should I cough up the dough now or enjoy the stock gearing and worry about it down the road at a later time? Appreciate any input.
Does’nt matter if you’re doing street or highway driving. What matters is what engine you’re using. The Graz is geared for a high revving Audi/Lamboghini V8/V10. So if you’re using a US V8 (GM, Ford or Hemi) you want the 1.04:1 or 0.90:1 gear.
The 0.90:1 if a lot of highway, the 1.04:1 if it’s mostly street.
 

Ron McCall

Supporter
Johan is absolutely correct. The stock gearing is marginal for a Coyote but pretty miserable for a LS7 or LT4.
Also, from my experience, the stock drop gear is by far the weakest part of that trans. I've repaired several
stock engined Audi R8s with broken gears. These were cars that were driven hard but It's not pretty when it happens.

Ron
 
Thanks All.. i'll most likely be using a GM crate - LS7 or LT4 are the top two at this point. I think what i was looking for is if the stock Graz is really that miserable with a GM block. Sounds like it is. It seems there are plenty of people out there without drop gears, but you just don't read about the complaints all that much.
 

Joel K

Supporter
Chris, I chose the .9 drop gear set for an LT4. I plan to do a lot of highway driving. I recommend you reach out to Cam T, he has driven his SLC quite a bit w/o drop gears on the Graz and can give you some real world experience.
 
In the other tab (RCR Forum - RCR40/SLC/917/Superlite Aero) there is a great discussion on this very topic which has a lot of data to help in making a decision (in case you didn't see it). On post #10 of "Graziano Gearing and Drop Gears" I posted an excel spread sheet that may interest you. I wanted my car to behave more like my stock C6 Corvette. While the final drop gear I installed (.903) isn't included, I found that with the stock Graz, I was running out of RPM very quickly in 1st and 2nd and it wasn't fun to drive. At cruise the RPM was still very high, and it sounded like the car was screaming to maintain speed. Looks like you're on the path to changing the drop gear.
 
went back and read Cam's blog, and seems his opinion is to have the gears swapped pre-install.

"In its original configuration, I believe the Graziano transaxle is geared too short for a street driven SLC. I find myself almost speed shifting into 3rd; in fact, skip shifting second and going from 1st to 3rd would probably make driving in traffic a little less hectic. Optional drop gears are available from HCF Parts (operated by John Burer, a former SLC owner). I would highly recommend updating your trans to a taller gearset before moving forward with the installation. Now that I have my (stock) trans installed it’s going to be an extreme pain in the rear to remove my trans and have the gears updated – and it’s on the edge of being annoyingly geared too short that my laziness compels me to leave it as is until I’m forced to do a serious overhaul on the car. My preference would have been to drop the bucks to get the trans modified before installation but my time constraints didn’t allow for me to do this. If you’re running an LS based motor and the Graziano transaxle, do it, you’ll be happier that you did!"
 
I recommended getting drop gears installed from the get-go. This was my main regret of the car during build, thinking "I can just live with it" for the additional cost. I wish I would have done it up front, would make driving expense better, although still isn't bad at all. Super short first gear and 6th at 70mph is turning some RPMs (3k?)

Saying all that to say this.... the Graz is definitely not difficult getting out if you feel you'd like to wait to make your own choice or just don't want to spend the money at the moment. My thinking was to enjoy it for a season and over the winter, pull the Graz and ship it off while car isn't really being driven. This will be my 3rd winter with the finished car and I have yet to do it, not terribly concerned with it with miles put on the car....just on my "to do" list.
 
Chris, I have an LS3 which has a redline of 6600 vs the LS7 which I think is 7000, so not a whole lot of difference. I did the drop and the overdrive gears as I live in NY and will see both stop’n go heavy traffic along with good throughway and parkway speeds. I’m hoping the combo will offer drivability at the top and bottom, but it will lose a little in the middle.
 
I started off with LS7 and no drop gears. Car redlined at about 172mph. Gears where so low I generally just used 2/4/6 (did not use the odd gears). I now have a 4L turbo engine (turbocharged) that redlines at 8,000rpm and have the 1.04s. Even with a higher revving engine the drop gears are VERY welcome. The car is so light compared to the OEM cars it came in that even my 4L with a huge turbo can spin the tires pre-boost in 1st/2nd.

To me the only question is do you install them yourself or have Fran do them for you...
 
I am wondering how high of rpm I will need to match the stock gears?I can build an engine to suit more cost effectively than spending 4 grand plus on gears and the time it takes to do them.This LS7operates all season long on the track at 8000 rpm.https://www.motortrend.com/how-to/1811-build-de-stroked-ls7-for-high-rpm-road-racing/
 
I am wondering how high of rpm I will need to match the stock gears?I can build an engine to suit more cost effectively than spending 4 grand plus on gears and the time it takes to do them.This LS7operates all season long on the track at 8000 rpm.https://www.motortrend.com/how-to/1811-build-de-stroked-ls7-for-high-rpm-road-racing/
The R8 has a redline of 8500rpm so that would be a good start.
 
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