I've seen few threads on the topic, but they all did not contain any certain information. The story is that according to some sources Diablo had 3 gear sets: short, medium and long. Some said that only few gears were differenT with higher gears being the same. So far I'm sure that all gearbox ratios are the same 2.31:1 - 1st 1.52:1 - 2nd 1.12:1 - 3rd 0.88:1 - 4th 0.68:1 - 5th This ratios are not the total ratios. The transmission is designed to have 2 output shafts 2 sets of transfer gears, that transmit torque to front and rear wheels. So the actual "total ratio" would be gear ratio multiplied by transfer ratio. Example, 2.31 x 1.41 = 3.26:1 of total 1st gear ratio that drives the rear differential Front transfer ratio on ALL VT - 0.81:1 Front diff ratio ALL VT - 2.81:1 (front ratios are pretty weird, guess, that's tuned to keep viscous coupling awake at low speeds) The difference in "gear sets" lies in the rear transfer and diff ratios. Rear transfer ratio - 2WD, VT 5.7, early SV - 1.59:1 Rear diff ratio - 2WD, VT 5.7, early SV, GT - 2.41:1 Rear transfer ratio - VT 6.0, late SV, GT? - 1.619:1 Rear diff ratio - late SV - 2.53:1 So by changing the transfer ratio, you change the whole gear set shorter/longer, so you will lose/gain top speed at the cost of faster/slower acceleration. If we go through the various combinations the shortest one is late SV. A rough comparison of it to an early VT would say that in total (with shorter transfer gear AND short diff) the late SV gear set is only 7% shorter. Nothing certain on SV-R and other rare/special modifications... Please, share your knowledge. I hope to see some brochures on longer ratios than mentioned. Also it would be good to know transfer ratios for Murcielago, as those are always skipped in the specs, only total ratios published. Thanks, Alex.
Maybe a good place to start: Diablo 5th gear normal ratio part #0024001212, low ratio 5th gear part # 0024001860 -mick
As far as i know, late SV have the same gear ratio like SV-R. But i cannot confirm that. From my experience i can say that my late SV (MY99) has a much shorter gear ratio than my MY97,5 Roadster.
That's a good reference, but where would you get the difference? Gear counts? Yeah, SV-R gearbox seems much shorter, but by how much? The lowest I could combine is 7% difference. People say it feels much shorter. I have no references for any other gear ratios than mentioned. So I wonder if they were published or if someone knows.
The difference is just the normal N i.e. the # teeth. The shorter ratio was 0.694:1 and was available on 6.0's and 99's - at the very least. -mick
Some news: I've found that there was an optional rear transfer ratio of 1.667:1. Standard 6.0 was 1.619:1. This was mentioned in 6.0 brochure.
So an absolute gear ratio of the longest combination 2.31 first gear * 1.59 rear transfer * 2.41 diff ratio vs the absolute shortest one 2.31 first gear * 1.667 optional rear transfer * 2.53 late SV diff ratio is roughly 10% shorter in all range. An optional 6.0 5th gear (0.694:1) + an optional 6.0 rear transfer ratio (1.667:1) + late SV diff (1.53:1) would be 12% shorter if compared to 5th gear on '92 2WD Diablo (i.e. the longest combo). The car was still referred to as 205 mph top speed. (No lower top end mentioned for shorter ratios) .
So am I to understand the 6.0 VT vs the 6.0 SE only differed (in terms of gearing) in the optional rear transfer ratio? Or the transfer ratio, rear diff drive, and/or 5th gear?
The variations of the viscous coupler gearing (what you call the rear transfer) predated the 6.0 and was available on at least the MY99 cars. It seems to me that the numerous gearing options were poorly documented as they were often market specific (in many cases just USA) and never made into print until cars (like the 6.0SE) included these options as base/standard features at which point what was an option vs what was standard flipped. -mick
The front axle got its own transfer ratio (on paper), however, I don't get how this all is actually coupled together as per parts diagram there's only one shaft. So I don't see where 0.81:1 ratio sits.
Greatly put together! Thanks! I think the actual development goes back to SE30 and the outcoming GT2 and other projects, when they wanted better ratios for racing. Basically, everything was available long before, but as an option. So, yes, SE simply came with a bunch of optional features as standard.
No surprise as no options were available at this time frame. And this is why there is confusion as this brochure is incomplete as compared to the workshop manual. As per the WS manual, the options started to appear with MY98 i.e. the VVT engine but seem to be more prevalent starting with MY99 onwards. -mick
One of the attachments obviously got translations problems. They claim "rear final ratio" twice as 2.81:1, which is true only for the front. BTW, as a comparison, Murcielago has got 2.93:1 front diff ratio (2.933:1). The rear is the same as on late Diablo SV - 2.53:1 (2.529:1). (The actual differentials match by P/Ns, the cases are different) The transfer gears different - 1.242:1 (they claim only one transfer gear ratio). So the gears in the transmission are much shorter themselves, if compared with Diablo trans.
My '91 has very long gears compared to my '96 SV. The SV has to be in second to reach 100kph (indicated) while the '91 is still in 1st. The SV drives in an extra higher gear in all conditions compared to the 91.
Guess I need to be careful with my words ;-) Gears 1 thru 5 remained the same in all cars until MY 98 where the options started. Rear diff (final drive), was the same in the SV (at least MY 96 and 97) and SE but was shorter than the other models of the time. -mick
