jimlab

Here ya go...

FD w/HKS 6-speed, 4.77 R&P, P275/40-17 tires
1st - 2.733:1 - 13.04:1 final drive
2nd - 1.984:1 - 9.46:1
3rd - 1.548:1 - 7.38:1
4th - 1.246:1 - 5.94:1
5th - 1.000:1 - 4.77:1
6th - 0.807:1 - 3.85:1
Cruising, 3rd gear, 30 mph - ~2,900 rpm
Cruising, 6th gear, 70 mph - ~3,530 rpm

ForceFed

I agree with #1, Jim, but how do you come up with #2? I'm certainly not questioning your knowledge on this, but would like a logical and if possible, mathmatical explanation for #2.

Thanks,
Darril

Kento

1st and 2nd gear on the HKS gearbox are taller than stock. Your engine will have to work harder out of the hole, resulting in a slower ET.

rx7tt95

Its really designed for road racing. I actually talked to HKS about this box when it first came out. It needs a full service and inspection every 3000K miles. No kidding. Isnt the RX8s tranny the same as the RX7 except for the extra gear? Essentially the same case design I believe. Take an RX8 gearbox (which may be the same as the Miatas 6speed box) and acquire a Guru upgraded gearset. That is apparently what MVA is using with their three rotor RX8.

Another idea would be a GForce upgrade to a T56 if you really need the durability. But then theres the whole PPF elimination problem.

I have heard that HKS now has a more streetable 6speed box.

ForceFed

Kento, i see that now. When i had initially posted, i thought i had seen that the 1st gear was the only gear that was taller, but after careful re-inspection i see that 2nd gear is taller as well. All those numbers had me cross-eyed for a moment. If 1st gear the only gear that was taller, and all things being equal i think the 6-speed tranny would have yielded a marginally better ET but a little bit better MPH over the 5 speed. Of course real world testing would confirm this and this is all just speculation until someone gets a HKS box, which i don't see happening anytime soon...

D

particleeffect

no, totally different bell housing, will not fit, been covered dozens of times.

POM HB

jspecracer7,

I'm not expert nor knowledgable. But, I read a lot of specs of super car like Lambo (not limbo), Ferrari, or even Viper. Those car reach 100 kmh within first gear and I think that's how those cars can manage that incredible 0-100 kmh time...not spending time to shift. Will that fact benefit to your drag strip?

so, I come to think you might start from a dead stop a little bit slower, but you 'll gain the time back with prolly one less shift to a quater mile....but , of cause, it all depends on your engine power range to take advantage of the tran.

And, Jim Lab is your ticket!

jspecracer7

Ya, I looked at that, but I think with the 4.777 final gear ....

Maybe I'll stick with a Guru Dog instead.

jspecracer7

But I don't have a 4.1 final gear, I have a 4.777 so even though 1st gear is Taller, my overall final is still lower.

particleeffect

but for drag racing, would you really need such tight rpm windows? even with mad quick shifting you'd still be rowing alot down the strip.

not saying you couldn't put it to good use in your uber car, just wondering. also, would/could your uber shifter fit the 7 gear pattern?

t-von

iTrader: (8)

You are exactly right! Only problem is 13b's don't have enough low end torque to be geared like those exotics. Now a 20b, thats a differant story. Personaly I would love to be able to go all the way to 60 in first gear.

jspecracer7

Um...I do run the shorter 4.777 final gear...that's why I'm considering using it. I don't advice it for ANYBODY using the stock 4.1

Crazy_Jake

RE Amemiya uses a Hewland 6-speed sequential gear box in that white Super G FD. Just push the shift **** forward once to progress to the next gear, then once you're at the top, 5 clicks back to nuetral. The tranny ain't cheap though.

Here's the Hewlan site

Here's the car

clayne

You would be stupid to spend 2000$ on a manual transmission like this without buying 4.777 gears first.

7mania

So what you are saying is that the 4.777 gears is best suited for this type of transmission. What is the benefits of using the 4.777 instead of other final gear ratios and would this setup be streetable.

Can anyone do the math and calculate the maximum speed through each gear and the top speed for the HKS 6 speeds gear ratios with the stock 4.10 and the 4.777.

clayne

No I'm saying that 4.777 gear set is way more useful, economically and application-wise, than this 2500$ transmission.

jimlab

If by streetable, you mean could it be driven on the street, the answer is yes. If by streetable, you mean is it something that you'd want to drive on the street, the answer is probably no. The increased rpm would mean the car would be louder in every gear, all the time. It would also mean faster consumption of fuel. I think you'd quickly get tired of the higher revs.

FD w/HKS 6-speed, 4.10 R&P, P275/40-17, 8,000 rpm redline
1st gear - 55 mph
2nd gear - 75
3rd gear - 96
4th gear - 120
5th gear - 149
6th gear - 185

FD w/HKS 6-speed, 4.77 R&P, P275/40-17, 8,000 rpm redline
1st gear - 47 mph
2nd gear - 65
3rd gear - 83
4th gear - 103
5th gear - 128
6th gear - 159

Note that these are gear-limited top speeds, calculated with the circumference of a perfectly round tire. Wind resistance, tire compression, road surface friction, and analog gauge inaccuracy mean that actual top speeds in each gear will be lower.

jimlab

I reinstalled Car Test 2000 and ran a simulation for an FD with 364 RWHP (Brooks Weisblat's dyno curve) and the HKS 6-speed...

With 4.10 gears, P275/40-17s, and a 3,000 rpm launch...

60-ft. - 2.25 sec.
0-60 mph - 4.12 sec.
1/8 mile - 8.02 sec. @ 96.97 mph
0-100 mph - 8.71 sec.
1/4 mile - 12.08 sec. @ 123.10 mph
40-140 mph, rolling start - 12.14 sec. (2nd gear start, 3 shifts)
Estimated fuel economy - 14.7 MPG city, 20.6 MPG highway

With P305/40-16 M&H slicks, and an 8,000 rpm launch...

60-ft. - 1.76 sec.
1/8 mile - 7.37 sec. @ 96.88 mph
1/4 mile - 11.41 sec. @ 123.65 mph

With 4.77 gears, P275/40-17s, and a 2,900 rpm launch...

60-ft. - 2.11 sec.
0-60 mph - 3.84 sec.
1/8 mile - 8.00 sec. @ 95.89 mph
0-100 mph - 8.42 sec.
1/4 mile - 12.10 sec. @ 125.49 mph
40-140 mph, rolling start - 12.73 sec. (2nd gear start, 4 shifts)
Estimated fuel economy - 12.7 MPG city, 17.7 MPG highway

With P305/40-16 M&H slicks and a 7,900 rpm launch...

60-ft. - 1.60 sec.
1/8 mile - 7.29 sec. @ 98.19 mph
1/4 mile - 11.34 sec. @ 126.65 mph

Keep in mind that this is just a simulation program, and real world results may (and probably will) vary.

MazdaRx7Racer4Life

I think the best aspect of the 6 speed (no im not a ricer) is the bragging rights to it.