Tall first gear impressions

[diss7]

I'm looking at gear/final ratios for the ae86, and have found a setup I quite like. My only concern is that I end up with quite a tall first gear. The car is about 950kg, and since the motor is 2000cc with a near standard head, I didn't think it would be too bad.

Anyway, here's the speeds / rpms that I've worked out based on the box/diff/tyres.

RPM KM/H
3000 32.29506246
3500 37.67757287
4000 43.06008328
4500 48.44259369
5000 53.8251041
5500 59.20761452
6000 64.59012493
6500 69.97263534
7000 75.35514575
7500 80.73765616
8000 86.12016657

Any one running or had any experience with a 1st gear this tall?

[Dell'Orto]

Randomly, my uncle had a MK1 Escort which had some strange gearset in it, which would pull 90 in 1st. Pulled pretty well, given it was only a mild Cortina engine in it, I assume the diff was really short too. Its generally how they make a close ratio box, really tall first then stack them in close after that with a short final drive.

[d1 mule]

have you used it properly (at the track) yet?

might be perfect how it is...

[saft]

I have a very tall first gear.. in a car with large cams and a triple plate clutch. Its a little hard to get moving but not unbearable.

According to the interwebs my ratios are:
1 2.519
2 1.820
3 1.300
4 1.000
5 .807
6 .650

4.11 final drive

275/40/17
8000 rpm
59 mph

8500 rpm
62 mph

9000 rpm
67 mph

9500 rpm
72 mph

[strx7]

According to the interwebs my ratios are:
1 2.519
2 1.820
3 1.300
4 1.000
5 .807
6 .650

those ratios look similar to corvette/viper 6 speed ratios

[saft]

Hks

[diss7]

I have a very tall first gear.. in a car with large cams and a triple plate clutch. Its a little hard to get moving but not unbearable.

According to the interwebs my ratios are:
1 2.519
2 1.820
3 1.300
4 1.000
5 .807
6 .650

4.11 final drive

275/40/17
8000 rpm
59 mph

8500 rpm
62 mph

9000 rpm
67 mph

9500 rpm
72 mph

Thanks for the info. Thats taller (well my first would be slighter taller, but you have huge tyres) and in a GTR I'm guessing. **Edit - Clarify, my first ratio in the gearbox is slightly taller, but because your tyres are much larger than mine, you are getting more speed/rpm then me

have you used it properly (at the track) yet?

might be perfect how it is...

Yes have been to track. Overall the gearing is too short, but yes can be solved by changed final drive. But the gears aren't evenly spread. 3rd is taller than it should be, so end up having too much drop from 2nd to 3rd, and 3rd to 4th ends up with much less of a drop than elsewhere. I'll do up some graphs so you can see what I mean.

[KinLoud]

What gearbox are you using?
What engine? What rpm is max torque and max power
"Short" vs "long" vs "tall" gearing?

What track do you use?
What speed/revs at the end of the fastest part of the track?
Ideally you might just hit the rev limiter in top gear at the fastest part of the track

Ken

[diss7]

Current setup (Stock Altezza box w/4.3 final) See what I mean about the 3rd. Also, because its a road focused box, first needs to be short. For me, this gear is unnecessary and I'd rather lose this gear, space first out to near current second, and gain an extra gear up top.



Proposed new setup with 4.1 final. This setup will be good for fast drifting tracks - B track Ruapuna for example. It will be just a fraction too short I believe for grip racing at Ruapuna, but might be okay depending on if I can rev to 8k. Will know about this when the motor is tuned. Otherwise would have to go 3.9 rear.



Proposed new setup with 4.3 final. This setup will be good for slower drift tracks - A Track Ruapuna, Levels, for example. Of course, have the option of slipping in a 4.5,4.8 or 5.1 if tracks are even slower.



Finals can be changed to suit the track, but the ratio spread/rev drops within the box are constant.

[diss7]

Interestingly, thats how I space my ratios in Gran Turismo. Very tall first, as tall as it will let me. 6th rev limit shortened right up, as short as it will let me. Space the rest in between with shrinking drops, then change final to suit track so top of 6th is bang on for the quickest part of the track.

[DRFTIN]

Proposed new setup with 4.1 final. This setup will be good for fast drifting tracks - B track Ruapuna for example. It will be just a fraction too short I believe for grip racing at Ruapuna, but might be okay depending on if I can rev to 8k.

yeah for my car a good ratio for b track drift is 4.1 and for racing those same corners a 4.6 was good to run 3rd gear. pretty big difference
and levels drift actually is faster than any ruapuna section, i often run out of revs there with the 4.1 in 3rd gear

the other thing you can do to make small changes is tyre size, can help a lot

as for 1st gear, i'd put it around a 1.5 if i had the option

[Bazda]

If your gona drive it on the street alot then it may be a pain.
Just take off in 2nd gear how your box is and see how it feels.

[matt dunn]

My car will pull 100Kmh in 1st at 8500rpm,
and doesn't come on boost until almost 60kmh.

I thought it would be hopeless of the line, but if launched correctly it will take off fine,
and the doesn't mean dumping the clutch from the limiter,
just have to launch at the correct rpm,
and you actually end up with one less gear change than most to the first corner so works quite well.

However having driven a few road cars with a tall 1st gear it is a PITA most of the time for daily driving.

[diss7]

Thanks for the feedback.