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mt75 vs type 9
omega0684 - 20/12/05 at 12:54 PM

hey guys and gals, im planning my build and intend to use a 2.1 litre pinto with fr32 cam and max flow head, with twin 40 dcoe webbers. i have got a cossie rear axle with 3.62:1 ratio lsd.

i need help with my gear box choice, which is better the type 9 or the mt75, i have both in my garage at the moment but i dont know which to use, what are the pro's and cons of each? and wot prop shaft do i use?

All help welcome

Kind regards

Alex


smart51 - 20/12/05 at 12:57 PM

which weighs less? Less is better.

What speeds will you get in each gear, with each box? At what road speed will peak power be achieved in top gear?

Which can you sell for more money if you keep the other?

Which is in better condition (will be more reliable)?

Which will fit your kit?


ditchlewis - 20/12/05 at 01:45 PM

I believe that the type 9 is the smaller box so good if space is at a premium in the transmission tunnel, whilst the MT75 is the stronger box.

so if there is space use the stronger box.

ditch


Mr G - 20/12/05 at 02:04 PM

Try the SEARCH Facility.


http://www.locostbuilders.co.uk/viewthread.php?tid=27425

http://www.locostbuilders.co.uk/viewthread.php?tid=12493

http://www.locostbuilders.co.uk/viewthread.php?tid=10534

http://www.locostbuilders.co.uk/viewthread.php?tid=29477

http://www.locostbuilders.co.uk/viewthread.php?tid=22681


mookaloid - 20/12/05 at 02:08 PM

Either box will be strong enough for a pinto engine.

You may wish to build your chassis so that it will take either in case you want to upgrade to a more powerful motor later.

it would be worth checking the ratios as the standard Type 9 1st gear is a bit low so if the MT box ratio is a bit higher it might be worth going for that box first.

HTH

Mark


Liam - 20/12/05 at 03:09 PM

I'd go for the MT. Stronger and a nicer gear change and should be lighter. Whatever you use you'll have to have a prop shaft made. The prop company will ask what box, what diff and how long, and that's it.

liam


Mr G - 20/12/05 at 03:21 PM

quote:
Originally posted by Liam
I'd go for the MT. Stronger and a nicer gear change and should be lighter. Whatever you use you'll have to have a prop shaft made. The prop company will ask what box, what diff and how long, and that's it.

liam


I hope they ask 'What postal address?'


zetec - 20/12/05 at 04:44 PM

If it's of help I use a MT75 from a DOHC Sierra with a 3.62 diff and 15" 195/50 tyres.

Speeds @6500rpm 2nd = 60-65mph
3rd = 90-95mph
5th gives about 23mph per 1000rpm

1st is low in both 'boxs but still usable, snatch 2nd at about 20-25mph and 2nd drags you up to near the legal limit if need be.

Can't remember what 4th does.

The only way around the low 1st is to fit a modded type 9 with long first and close ratio gear set, this works out about £500 including new bearings and a general freshen up. MT75 cannot have new gears fitted but of the two it is my choice as it is very robust, nice change and the gear lever is very easy to extend back to get the correct place in the car.


alan wheeldon - 21/12/05 at 06:18 PM

Ive got a type-9 running my standard 2.0 pinto and on the motorway its horrible, im doing about 70mph and its reving its nuts off.

Is there different ratio type-9 boxes? ie. 1.6 1.8 2.0 engines. If so i think i might be using the wrong one??


iank - 21/12/05 at 07:27 PM

quote:
Originally posted by alan wheeldon
Ive got a type-9 running my standard 2.0 pinto and on the motorway its horrible, im doing about 70mph and its reving its nuts off.

Is there different ratio type-9 boxes? ie. 1.6 1.8 2.0 engines. If so i think i might be using the wrong one??


What ratio diff and what wheels/tyres are you using as that sounds like be the problem.

I don't think changing the gearbox ratios would help (4th is 1:1 on both I think and 5th won't be much different 0.82 on type 9 IIRC).


alan wheeldon - 23/12/05 at 07:15 PM

15" alloys and a 4x4 lsd


NS Dev - 27/12/05 at 05:29 PM

maybe revcounter wrong then!!!!

I have used a stock sierra 2.0 type 9 in my old rally car on a 4.6:1 ratio atlas axle and that was fine at 70 (ok was revving but not that bad!) and you only have a 3.62:1 diff....................


britishtrident - 27/12/05 at 11:02 PM

quote:
Originally posted by alan wheeldon
Ive got a type-9 running my standard 2.0 pinto and on the motorway its horrible, im doing about 70mph and its reving its nuts off.
snip




You must be running much too short a final drive ratio ---


locost_bryan - 28/12/05 at 02:29 AM

quote:
Originally posted by britishtrident
quote:
Originally posted by alan wheeldon
Ive got a type-9 running my standard 2.0 pinto and on the motorway its horrible, im doing about 70mph and its reving its nuts off.
snip




You must be running much too short a final drive ratio ---



... or your speedo's not calibrated right - maybe you're doing more than 70?

Find out your tyre size, diff ratio, and gear ratios, then visit this site http://www.customspeedparts.de/content/en/technic/getriebeberechnung3.php to calculate the road speed for each gear.


alan wheeldon - 28/12/05 at 03:10 PM

the speedo and rev counter are fine, it wouldnt have got through the SVA otherwise??

I think i must just be running the wrong gearbox for the engine??


rusty nuts - 28/12/05 at 03:24 PM

4th gear in all type 9 boxes is a 1 to 1 ratio 5th is in effect an overdrive around .9 to 1 . Changing the gearbox will have no effect on revs/road speed . The final drive ratio / rolling radius of tyres will have an affect .


Peteff - 28/12/05 at 04:37 PM

You notice it because the silencer is next to you and it sounds busy. What revs are you actually doing at 70mph in 5th? There should be plenty left to go at.


alan wheeldon - 30/12/05 at 04:38 PM

it does about 4 to 4.5 revs in 5th gear about 70mph. I thought that was high or is that about right for a 2.0 pinto??

your right about the exhaust as well being right next to you, it sounds much louder


zetec - 30/12/05 at 10:50 PM

That does sound high, I would have thought you shound be aiming at 20-23mph per 1K at least. The Pinto being a torque engine for this car, you should be looking for 25mph per 1000rpm.


MikeRJ - 31/12/05 at 01:51 AM

quote:
Originally posted by alan wheeldon
the speedo and rev counter are fine, it wouldnt have got through the SVA otherwise??

I think i must just be running the wrong gearbox for the engine??


SVA dosen't check the accuracy of your rev counter!