S2000 Under The Hood S2000 Technical and Mechanical discussions.

Differential Gearing

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Old 07-27-2001, 07:55 PM
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Default Differential Gearing

Recently I was reading some posts on possible gearing of the S2000. The whole discussion was about 1-6th gears and top speed. I wonder if the launching problem with the S2000 could be improved by changing the rear end gearing.

You have to rev the engine to 6k and smoke the tires for a distance to get a good launch. On top of that, it
Old 07-27-2001, 08:45 PM
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Gary, let me offer you my personal opinion on why the S2K is geared like it is. 2nd gear has to be good for at least 60.1 mph. Why? Because 0-60 is a common measurement and if you have to make an extra shift, it hurts the time. Now, if 2nd gear has to be good for a little over 60 mph, then to keep the car in VTEC on the 1-2 shift you have to be able to do at least 40+ mph in first.

You could also make a case that as a sporting roadster you want nice tight ratios and you're willing to sacrifice off the line so that first is actually usable in a corner.

But, your suggestion of tighter gearing would work. You could either change the first 4 ratios in the box, or change the rear gear. Even changing from a 4.10 to a 4.40 would do a world of good. 7% more torque multiplication would net you the ability to drop the revs on launch by at least 500 rpm, maybe more. Personally, if I were building a NA version focused on dragging (while remaining streetable), I'd probably want to drop first by about 10%, 2nd the same. 3rd could come down about 7-8% and 4th about 4-5%. You'd still be able to hit 110 mph in 4th while leaving 5th and 6th alone.

In my case though, the dragging is the last thing I have on my mind when in my S2K.

UL
Old 07-28-2001, 05:45 AM
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I wanted to change the gearing since I got the car, I wanted a 4.44:1 rear and a .7 or close 6th.

I think you could still get to 60 with the 4.44 ratio, but definatly not make the 0-100Kmh
Old 07-28-2001, 10:28 AM
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Pssss, secret: "I run 20" tires on the stock wheels at the strip."
Old 07-28-2001, 02:05 PM
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Originally posted by cmnsnse
I wanted to change the gearing since I got the car, I wanted a 4.44:1 rear and a .7 or close 6th.
The rear should be easier to change (if available), but I would think that changing any gear in the transmission would be a big deal. First, where to get the gear, and then the major project of installing it.

My interest is 0-60. I've seen figures on what each gear does with different rears, but nothing about how this affects a particular speed range. For the best 0-60 times it is necessary to do it with one shift. That tells me that I want 2nd gear to be in the power range at the end of 1st, and able to take it just past 60. And most important, I want 1st gear to allow me to keep engine rpm up at launch without instantly taking the tires to 30 mph (smoked). Anyone have any idea if this can be done with the present transmission gears, and what differential gearing that requires.

Has there been anyone providing any options for gearing for the S2000 rear end?
Old 07-28-2001, 02:11 PM
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Originally posted by RT
Pssss, secret: "I run 20" tires on the stock wheels at the strip."
That's another option that changes the effective rear gearing. My thinking is that the tires need to be even a smaller diameter than stock. That would look goofy wouldn't it!
Old 07-29-2001, 12:12 AM
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all this talk about the diff.

Who actually makes one?? and how much are they selling it for?
Old 07-29-2001, 12:42 PM
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I hope we can get some input on what's available. I've read that the diff in the S2000 is manufactured by another company - and used in a few other vehicles. If anyone knows the skinny it would be interesting to know. Seems to me that someone like Comptech or Spoon could provide THE GEAR that would be in the sweet spot for 0-60...I think there would be interest.
Old 07-30-2001, 07:56 AM
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Js Racing, Spoon and Jets make rear differential for the S2K.
Spoon makes a 4.33
J's has 4.44, 4.77 and 4.55
I think the Jets is a 4.55
Old 07-30-2001, 09:48 AM
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Originally posted by ultimate lurker
You could also make a case that as a sporting roadster you want nice tight ratios and you're willing to sacrifice off the line so that first is actually usable in a corner.

UL
UL,

I cannot downshift to first unless my car is rolling super slow, I'd say no more than 5mph. Is something wrong with my synchro or is this normal in our cars?


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