gearbox t1

[pirate]

hi all, is there any diff between a standard city box and a turbo 1 box???, like ratios or mountings etc, any advice will help, thx andy

[Colza]

Mountings will be the same. Belhousings and flywheels probably different but if you keep the flywheel and clutch with its respective gearbox is should work out. Ratios almost certainly different.

Bear in mind this is all speculation and not at all based on fact

[Mark_Moddy]

THe std diff ratio should be 4.25.
The turbo diff ratio is 4.05.

[civic_killer]

If you need a cheap gearbox just get a gen 1 civic box, they are cheap as chips and fairly strong. i had one in mine and never had any problems

[pirate]

hi, ok, well my turbo had 12inch wheels, it now has 13inch, if i use a civic box id be somewhere back to normalish ratio???, give or take a bit???, thx andy

[Colza]

It really doesnt matter in the slightest aye. With a non turbo box you would have ever so slightly more torque at the bottom of each gear, and you will be doing ever so slightly higher revs at the top. If you were doing competitive racing then a 5% change in final drive might be important, but for daily driving you wont even notice.

[Mark_Moddy]

If you want good acceleration definately get a 4 speed Series 1 Civic gearbox.

They have a really good 4.93 diff ratio.

You will sure feel the difference.

[James]

Damn that is a revvy box, that would be a good box for drag racing a city prolly, unless you maxxed out 4th before the line  ;D

[John_S.]

Hey Mark, et al, I don't know what years and models the 1st and 2nd Gen Civics in Australia had which gear ratios. But in the US there was a fairly wide range of ratios. A search on Richard Nasr's discussion page should turn up a chart I sent to Dr Zoom a couple of years ago,(I think it might be on his page too), that lists them and the tag codes very accurately...'73 to '83, the end of our 2nd Gen production.  If you want a "close ratio" 5-speed, you want an early 2nd Gen 1300 transaxle, our years for this were '80-81. It had a tight gear spread and a 4:93 to 1 final drive. In '82 they used an extremely tall 3:72 to 1 final drive. Another good choice...for the road I think the best... is the '80-81 Wagon 5-speed tranny, with a 4:42 final drive. That translates to a road RPM of 3500 at 70MPH, for kilometers you'll have to do the math. Oh I think top speed in fifth at 6000RPM is around 122MPH, and I'm guessing some of your cars might touch that easily.

[Colza]

You dont happen to know the tag numbers for that 80-81 5 speed do you? I have one here that fits the description, but im not sure if it will be the sma ebox or not...

[John_S.]

OK,
80-81 Civic 1300 close ratio 5-speed           4:93 final drive
1st   2.916
2nd  1.764
3rd   1.181
4th     .807
5th     .655
3493 RPM at 70 MPH.......6000RPM at  120.2 MPH in 5th
USA factory tranny code....GJ8600001_on

80-81 Wagon 1500                                      4.428 final
1st   2.916
2nd  1.764
3rd   1.181
4th     .846
5th     .714
3419 RPM at 70 MPH.......6000RPM at 122.9 MPH in 5th
USA factory tranny code....GM8500001_on

82-83 Wagon 1500                                     4.266 final
1st   3.181
2nd  1.823
3rd   1.181
4th     .846
5th     .714
3293 RPM at 70 MPH......6000RPM at 127.5 MPH in 5th
USA factory tranny code....'82  GM8700001_on
                                         '83  GM8900001_on

I don't Know if this will help you per your codes, but let's hope...

[Colza]

Mine is a GN-87xxxxx

But i have just remembered that that isnt the original gearbox ::) that gearbox is from an 198x civic sedan, so god knows whats inside it!

[John_S.]

We (USA) have a GM87000 from '82 1500 Sedan:

1st   3.181                                 3:875 final drive
2nd  1.823
3rd   1.181
4th     .846
5th     .714

2992 RPM at 70 MPH........6000RPM at 140.4 MPH

Considering the torque of a turboed car this one here, if it is the one you have should kick serious ass!

[John_S.]

Colza,
I just thought of one more source I have that might also add some valuable info. Our EM87000 goes behind an EM1 1500...I'm guessing your EN87000 was behind a EN1. Am I right? If so, I have the gear ratios for the British version of our '80-83 Civic Sedan, which in Britain was badged as a Triumph Acclaim.( Bought a Haynes manual over eBay when I found out that fact.)
I was "tripping" over the fact that I now have an '83 Honda 4-Dr Sedan, which is also a Triumph. You see my first car was a 1964 Triumph TR4, and my second car was a brand new red 1970 TR6. Goes around, comes around.
Anyway, the Triumph Acclaim had a dual carb version of the EN1, so I'm taking a wild guess that your transaxle might be the same gearing as the Triumph is:

1st.....2.916:1
2nd....1.764:1
3rd.....1.181:1
4th........846:1
5th........714:1                    Final drive....4.642:1

Sorry, the Haynes book does not have the actual tranny code in it.
Later Dudes....

[James]

Thats mental is had dual carb!! That would be a seriously cool car to get over here in NZ. Even a cool engine to see, i wonder if it goes any better than the single carb does??

I just grabbed the 1980-81 Honda civic (no-US) manual out of the cupboard so lets see what it has to say..

it says the 4 and 5 speeds fitted to 80-81 EN1's had these ratios

1st                                 2.916  :  1
2nd                                1.764  :  1
3rd                                 1.181  :  1
4th                                 0.846  :  1
5th  (when fitted)          0.714  :  1
Reverse      2.916  :  1

Unfortunately it fails to include the effing diff ratio  >:(