Final drive calculation.

[Aram]

Strange, I changed the cable to the speedometer from electronic to mechanical, maybe something is off there?

[Aram]

(11-17-2014 03:12 PM)Uzelac Wrote:  4.3 is standard for AE86, 4.1 for AE86.

You can use this sheet i created some years ago to test everything:

https://docs.google.com/spreadsheets/d/1...y=CNqEs-cI

What do you mean with "4.3 is standard for AE86, 4.1 for AE86.", they both are common?

I tried your sheet but I don't have enough knowledge to see what it does?

Aram.

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(11-17-2014 06:38 PM)oldeskewltoy Wrote:  The CableX is the simplest solution, albeit not the least expensive.

Tire diameter, as well as an in-accurate speedometer will cause havoc on accurate speed readings.

As far as running a 3.3 final drive.... I had a 3.58 final in my E7 Corolla, and with that I barely had a need for 5th gear..... I've since moved to a 3.90.

So maybe it is best to swap to 3.9 for lower revs at highway cruizing speeds and then do the last bit with this Abbott CableX?

Aram.

[banpei]

I think he meant 4.3 for most of the AE86, 4.1 for SR5 and AE85

[ditn]

3.9 on a na engine will be slow i think,i always thought 3.9 was for a turbo or supercharger engine

[Bean]

(11-19-2014 09:51 PM)ditn Wrote:  3.9 on a na engine will be slow i think,i always thought 3.9 was for a turbo or supercharger engine

Don't forget he's running a Beams engine and got nearly 40% more torque than a 4A-GE.

@Aram: I'll make an easy to understand illustration later today

[Uzelac]

(11-19-2014 07:14 PM)Aram Wrote:  What do you mean with "4.3 is standard for AE86, 4.1 for AE86.", they both are common?

I made a typo, 4.1 is standard for AE85

Regarding sheet, i redone it, hope it is easier now. Everything is chosen and displayed on first sheet.

[oldeskewltoy]

no BEAMS here.... but I am running about 30+% more power then most 4AGEs.

Way back when I owned my blk AE86 coupe... it had a mild cam, a bit of compression, and planted 112 whp (about 130 @ the crank), I used a 4.10. A stock 4AGE w/T50 can likely use the 4.10 with few side effects.

In Surreptitious, when I had the 3.58... and an 8000 rpm redline... I was capable to do over 75 in 2nd gear

The current set up using the LEEN 6 speed gives me a 3.8 first gear (T50 is 3.5) this allows me a bit easier on the clutch when mixed with the 3.9 final... or when I had the 3.58 it made that easier too

[Bean]

later than promised but here goes:
use this link http://goo.gl/AOqKQy it should take you to an online calculator with graphs and all the data already in it. If you hover the mouse over the top two lines at different points it will show the corresponding speed and rpm to be expected.

If you want to try different final gears just enter the new number in the representing field and hit the lower right calculate button again

PS: the upper table also lists shift points for each gear. This is the rpm you'll have when shifting up to that particular gear at redline from the previous.

[Aram]

Thanks Mr. Bandit!

That is something I can work with.
I will check if those speed/rpm figures match with my current setup.

But something is not very cool.
If I give the second transmission set a final drive of 3.3 I do get the 130km @ 3300 rpm which appears on my speedometer now.
But then a 100kmh would be achieved at 2500 rpm. maybe not what I want.

Although the Z4 of a friend of mine does only 1800 rpm at a 100kmh and that pulls fine still.

And it would give a top speed of 295 kmh, nice if you want to scare the living sh*t out of yourself.

3.9 sounds better.

Aram.

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(11-17-2014 06:38 PM)oldeskewltoy Wrote:  The CableX is the simplest solution, albeit not the least expensive.

Tire diameter, as well as an in-accurate speedometer will cause havoc on accurate speed readings.

As far as running a 3.3 final drive.... I had a 3.58 final in my E7 Corolla, and with that I barely had a need for 5th gear..... I've since moved to a 3.90.

Do you remember what rpm at what speed you had back then, with the 3.58?

If the calculator sheet that Bean B. gave is correct than the data for 4.3 that I'm currently running:

120kmh = 4100 rpm
100kmh = 3300 rpm

Which sounds correct.
And that is not nice for long distance running, when going to UK or something you would be worn out before you get there.

3.9 then:

120kmh = 3700 rpm
100kmh = 3100 rpm

Which is better, but 3700 rpm is still a lot for only 120kmh, 3.58 might be better still:

120kmh = 3400 rpm
100kmh = 2800 rpm

And at 3.3 the speedometer would be correct again but:

120kmh = 3100 rpm
100kmh = 2500 rpm

Nice for cruising, but it will probably lose most of its pulling power over the range?


I'm at crossroads, I really don't want the car to be a slouch but at the same time I want to be able to cruise normally on the highway, what to do!!??
3.58 sounds about right at the moment for cruising, but what does it lose on pulling power?


Aram.

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(11-20-2014 02:00 PM)Uzelac Wrote:  

(11-19-2014 07:14 PM)Aram Wrote:  What do you mean with "4.3 is standard for AE86, 4.1 for AE86.", they both are common?

I made a typo, 4.1 is standard for AE85

Regarding sheet, i redone it, hope it is easier now. Everything is chosen and displayed on first sheet.

Sheet gives a error?

[The Doctor]

I went from a 4.3 to a 3.3 in my 125 bhp 2T-G KE20, weighing 910 kg.
With a T50 and the 4.3 diff, i could skip 1st gear, and 5th would be 5500rpm @ 120km/h.
Now i've got a usable (but slightly long) first gear and a nice cruising 5th, if i want to overtake, i can go down a cog in the box and it'll pull well enough. Only thing is, my 2T-G hasn't got the power to pull my boxy KE20 through the wind at higher speeds with this diff, thus the actual topspeed being lower then a standard 2T-G powered TE27 was (which should do 200, mine doesn't go past 170 atm), but it's fast enough for me, and the fuel economy is a great bonus as well (it does 1l/11km on a long run, not bad for a 40 year old 'racing engine' on 2 40DCOE Webers). My theoretical topspeed is 260 btw

Your BEAMS has got loads more torque and power, i think you'd be fine with a longer diff, especially with the 6 speed behind it. You can always shift down if needed, for instance, i can go back to 3rd on the motorway if i want to overtake, more then enough power then