They made ( I don't know who) an adapter plate for a B trans to fit on an H , why can't they make a plate and a adapter kit for the 6 speed trans? Doesn't the newer civics come with 6 speeds? It might not be any use to the natural H's but boosted ones it would be great.

 

For one the K series spin the opposite direction than an H. And what could you accomish with 6 gears that you can't with 5? There is an assortment of H or F trannies you could use if you want short gearing for more pep or long gearing for top speed and you wouldn't have to modify axles or mounts to swap it in

 

Ahem..would be nice to have an o/d gear for highway speeds. 4k at 80mph or whereabouts isn't o/d to me lol.

 

my k20z1 tranny sits at 4k @ 80. a k20a2 6 speed is right around ~3500. logic fail.

 

^Exactly. It's not like they added a 6th gear to a close ratio 5 speed, it's a 6 speed with it's own gear ratios and final drive. F series is the only way to go if you want to be at 3k @80mph

 

80mp/h in my f 94 accord = 2.9k...and thats with 4spd automatic...
80mp/h in my h 95 lude = 3.5k

agree @ 6th gear for highway...lol

 

You guys should quit complaining I'm at about 4k at 75Mph. M2f4 lol. I love it though.

 

f23 5 speed gearset into h23 tranny

This is what Im planning on, bought 5th ggearset out of a 98 accord I believe, mabey older dont have my part numbers on hand and Im using an h23 trans (because I had a couple, should work on h22 trans but I cannot confirm at the moment.)

I mic'd out the two sets and they are identical, both sit nicely on the h23 main and idler shafts. Havent reassembled the case yet and it will be a few months before the motor is ready now.

 

/\ That's awesome, I would love to do that just for the MPG benefit. My RX7 has 6 gears and you really can't beat it for highway driving.

 

Its already been done so it works fine. Not worth 4-5 more MPG IMO though...I get 28ish highway cruising at 3800 and my car isnt even tuned.

 

Wouldnt be worth it if I was paying someone, about 100 bucks shipped for a trans that is already out of the car, and quieter highway speeds (3" exhaust). I think it will be worth it for me.

I dont mind using the h23 trans either because ill have a 97mm crank and will be keeping it alittle under 8k rpms. Think this setup will work well for me.

 

That's cool man. My experience has been lower RPM cruising speed actually causes more exhaust drone. Every setup is different though. Let us know how it works out for you.

 

the jdm h22 tranny gears are short enough as it is. lol. and having a 6speed tranny on a prelude is:
A; pretty pointless
B; going to be pretty expensive with no real gain
C; once again, pretty pointless.

and as far as swapping an f series 5th gear into a hseries tranny for better highway cruising, im sure it can be done since everything f sreies and h series is interchangeable. i hear about people putting ls 5th's into b16 trannys etc all the time.

if ur looking for better performance just mod your engine dude.
that would be obnoxious as hell to have shorter 6 gears cus i shift into second going through intersections with 5

 

80mph at 3.2k 5 gear on a h23vtec with a f22 trans.. cant wait to turbo this damn things.. to freaking slow...

 

6th gear in most Honda transmissions is still geared down anyway. My AP1 trans was at like 4300 RPM in 6th at 80mph. It's better that these motors spin up on the highway. I took a trip to CA with my S2000 and I was able to just leave cruise control on thru the rockies since the car made enough power at 4200 RPM to easily maintain speed. Still got 30MPG. My ITR has the 4.78 trans and spins even higher. 33+ MPG on the highway at 80mph.

I don't see the issue. Wouldn't want a boggy 6th gear. I understand the H series makes good torque....but that's just a relative statement.

 

Not really. I don't feel like there is a need for a 6th gear.

 

on my ap1 I'm running a 4.7 something final drive so at 80 mph in 6th gear I'm at 5k rpm its great

 

I do have 6 gears!!

This:


Is going in this:









Black one is already up and running but everything is being transferred into the White SH. Minty..

 

That is a P2A8 Accord tranny. I put the 5th from one in my SH. RPMs @ 80 MPH ~3250.
RPMs @ 50MPH ~2100. Machining was required. So technically I have a 6 spd w/o a 5th. now.

 

Machining was required for the SH/5th gen? Was it enlarging the bore of the gearset or shaving the thickness down?

And btw hows the motor issues going?

 

The gears are 56 Rockwell (hardness). Both gears had to be machined thinner to match the M2U4 & M2Y4 5th gears (which are both the same part#). I got the idea from Catacon on pp.com (he had a 5th gen auto that he did a 5spd swap to, and did this 5th gear mod. for lower highway RPMs for better mileage).

I am sporting a new shortblock now with a Synchrotech M2U4 w/P2A8 Accord fifth gear.

 

How much better could the highway mileage be with that accord gear? 1-2MPG? Sounds like a lot of work.

 

If your car is stock or lightly modded (intake, header, exhaust, tune) and you are paying someone to remove the trans, install the gear, and re install trans then it would take years to offset the ~$1000 cost.

With I/H/E/VAFC I would guess from some of my research and some math ive done that you could gain 2-4 mpg highway. Even at $6 a gallon that would take a long time to regain.

For me Im touching everything in my build and have a known good H23 trans sitting at home. My cost will be about $100 in parts. Plus better intake manifold, Vibrant v2 header, full 3" exhaust, Hondata s300, minor head work, more compression, etc... I should see a much higher gain with a good tune from a large number of factors not just the one. Im hoping for a 5-7 mpg gain combined mileage and higher for highway mileage. Its hard for me to calculate with so many factors though.

As far as the cost factor for OPs suggestion of a 6 speed, (custom mounts to flip engine 180*, extended harness, custom header and exhaust, adaptor plate, k series trans, custom axles, and ruined weight distribution) you would never re-coup the cost in mileage savings.

 

thats sick man!! rack rack city bitch !

 

A 6th gear would be useless, give me a better 5th gear for highway and I'd be happy.

You only need 1-4 for the 1/4 mile ... 5th can be a bit longer, besides the first thing I do on the highway if I need to pass is down shift, so whats the point of such a short 5th gear?

BTW I have the JDM T2T4 tranny