Mi Box Onto An 8valve 1.9?

[TVR Gary 0]

Blew the guts out of mine so I need to do something about it. I have been offered a recon Mi box for cheap money.

 

Couple of questions

 

1. Will it fit without modification?

2. Will the gear ratio's be different and if so will the car be longer or shorter geared?

3. Have any of you done it and what were the results?

 

Gary

[smckeown 1]

gear ratios for comparison are in my sig. Here's a tip, on the tabs with the graphs, you can select the ratios (lines) other than say 1.9 and mi16 and delete them, therefore having just the 2 left to compare accurately

[pug_ham 242 3 Cars]

It'll fit but not strictly without any modification but the selector arm will need swapping to the one from your 205 gearbox to this one so all the gears work properly.

 

It'll be shorter all round than the 1.9 gearbox & not much diference than a 1.6 GTi gearbox just with a slightly longer fifth.

 

Graham.

[jonD6B 0]

I ran a 1.9 engine with an MI box and loved it. It was always quite high revving with ordinary driving but left me in the right revs to save me changing down when I wanted to shoot away which suited my driving style perfectly.

[jonnie205 1]

Its the best box to use in a 205. Stronger casing with cooling ribs, best CWP ratio and best gears. It will liven your 8v up no end.

 

Will bolt staright on the all you will have to do is swap selctor fork which is a piece of piss 5 min job.

[C_W 3 1 Cars]

Gary, what sort of revs in 5th are you hitting at the faster points at the 'ring?

 

I maxed out with my 1.6 gearbox down the hill but this is with an Mi16 engine so it will be happier pulling 7300rpm but I don't think a semi-standard 8v engine would want to. The mi16 gearbox IS a bit longer than the 1.6 5th but with the reduction in revs when using the 8v it might be something to think about. If you're not near maxing out with the 1.9 gearbox (as far as the 8v engine will rev anyway) then the Mi16's slightly lower 5th might be worth a go.

[TVR Gary 0]

C_W I hit around 125mph at the max currently. I would suggest I hit that twice every lap for maybe 5 seconds. Not sure what rpm that is though. I would be happy to back off slightly if that was going to put me too far into the red.

 

Im not very good at working out gear ratios etc but the current 8v box sits nicely through the tighter sections nailed in 3rd. I dont want buy a box which leaves me hung out to dry either revving too high in 3rd or out of the power band in 4th.

 

If I was pulling 70mph in third with the std box what revs would that be? and what would it be with an Mi box? Anyone know?

 

Thanks for the comments about it being a simple fitment by the way......

 

Gary

[smckeown 1]

why not raise the limit by 500rpm or so, if your in the power band for 10 secs longer at 125 mph then that will save you a good amount of lap time Plus running 500rpm for just 5 secs hopefully wont cause too much stress

[TVR Gary 0]

Its an old engine and has to last me the year

[Ahl 4]

I've got a mi box on my 1.9. I forgot to swap the gear selector arm before putting it on though, so that was a pain in the arse to change!

 

5th is about the same, I believe it does rev slightly higher for the speed, but not by very much. Mine puts out the same economy anyway.

 

The mi box does liven up the 1.9 to no end, but I find it less flexible than the standard 1.9 box. 1st gear is a lot less usable than it was and I find myself never quite the right gear a lot of the time. 2nd gear goes to 50 instead of 60 mph so is a bit too short when overtaking someone doing 40mph, so I have to use 3rd instead. 3rd gear goes to 70 instead of 80mph, so is again less handy when overtaking something doing 60mph.

 

Generally although it accelerates faster with the lower ratios, I find myself changing gear more and spending less time actually going fast past things.

The same box on a higher reving mi16 gives you same flexibility as the 1.9 but with faster shorter ratios. The standard ratios all make sense I guess.

[TVR Gary 0]

Mi16 box is going in next weekend so I hope it all goes to plan. Selector is the pin type so can easily be removed and changed for the one from my 8V box.

 

Box is arriving in Germany friday afternoon so fingers crossed I will be on track by Saturday ......

 

Gary

[jackherer 543]

Selector is the pin type so can easily be removed and changed for the one from my 8V box.

 

just in case you haven't already read this, don't let the shaft drop into the box when you change the selector, if you do it will dislodge something internally and you wont be able to select fifth and reverse until you strip the box down!

[pug_ham 242 3 Cars]

just in case you haven't already read this, don't let the shaft drop into the box when you change the selector, if you do it will dislodge something internally and you wont be able to select fifth and reverse until you strip the box down!

when I swapped the selector arm on mine I put the gearbox in gear to try prevent this, it worked but after talking to Miles that might've been just lucky.

 

You can check the all gears are still able to be selected before you start fitting the gearbox by moving the selector arms around & checking you can get six gears. To do this push or pull the other selector arm from the central resting position to check that you can get the other gears from I assume 3rd & 4th with it central.

 

Possibly not the best explanation but hopefully you understand what I mean.

 

Graham.

[arry 0]

I've got a mi box on my 1.9. I forgot to swap the gear selector arm before putting it on though, so that was a pain in the arse to change!

 

What happens if you don't change the selector?

 

I've got an MI16 (suspected) box on my 1.6 fitted by the previous owner - when the box warms up, the gearchange is VERY stiff and even in neutral it's like stirring tar moving the gearstick from side to side. Would this be a symptom of that?

 

I'm swapping back to a 1.6 box anyway, as at the moment 80mph on the motorway is not exactly cruising - it's revving the nuts off it - just under 6k rpm ish

[TVR Gary 0]

Not sure why that would be arry, I think the Mi boxes fifth gear is the same ratio as that of a 1.9 box?

 

thanks for the comments guys, everything is noted

 

Gary

[pug_ham 242 3 Cars]

What happens if you don't change the selector?

Not sure but I assume you can't select all (if any) gears.

I've got an MI16 (suspected) box on my 1.6 fitted by the previous owner - when the box warms up, the gearchange is VERY stiff and even in neutral it's like stirring tar moving the gearstick from side to side. Would this be a symptom of that?

 

I'm swapping back to a 1.6 box anyway, as at the moment 80mph on the motorway is not exactly cruising - it's revving the nuts off it - just under 6k rpm ish

Linkages need looking at for condition & the subframe side to side bracket that clips on might need the balljoint it clips over cleaning & greasing. I had the subframe off my STDT this week & this balljoint (not part of the L bracket) was rusty & in need of a clean. I did this & greased it before refitting & its much better now.

 

I think I've posted about your gearbox on PSOOC & you don't have an Mi gearbox on your car, its a hybrid with mixed ratios. The Mi fifth gear is longer than the 1.6 one so it won't be revving at 6k when doing only 80mph. More like 3.5k max afaik.

 

The closest I can find that would equate to around 6k at 80mph is effectively third gear from the 1.6 GTi box with the Mi final drive which I can't see anyone using as fifth, even for competition use.

Not sure why that would be arry, I think the Mi boxes fifth gear is the same ratio as that of a 1.9 box?

There is about 200rpm difference between the two at 70mph.

 

Graham.

[arry 0]

cheers for the help

 

The linkages look fine and I've greased them with no joy. I'll have to have a look when the box comes off

[TVR Gary 0]

Update.

 

had the Mi box fitted to my 8V over in Germany. The selector had to be changed as advised, box went in fine and worked without issue. The old box when taken out had a hole the size of my fist in it, not much use any more

 

Differences.....

 

The Mi box is indeed differently geared than the old 8V box. The car feels more urgent and free reving. It does however mean that I have to make more gear changes than previous and sometimes at the most inappropriate moment. However its a learning curve and keeps things interesting.

 

Due to the higer reving nature I think I will be reducing the life of my engine, but I will cross that bridge if and when I come to it.

 

The speedo is a country mile out.

 

 

Thanks for all your comments on this one, it helped me no end

 

Gary

[TEKNOPUG 3]

When the FD was changed on my 'box - the speedo didn't change at all - even though it was 10+% longer gearing. I changed the dial unit and the speedo instantly corrected itself. Weird. It might just have been that I pushed the cable on better when I reconnected the clocks.

[SweetBadger 91]

The speedo is a country mile out.

 

My speedo was miles out when I fitted an MI box, only found out after fitting it that you have to replace plastic cog in the diff casing that drives the speedo drive with one from a 1.9 box if you want the speedo to be spot on, which involves removing a driveshaft and undoing 3 bolts holding the side cover on to get the damn thing out.

 

I assume you are using the speedo drive from the 1.9 box combined withthe drive cog from the MI box, which means the speedo will be way out (15%).

 

If you change the speedo drive to the one from the MI the speedo will only read about 3% over, preferable to pulling the driveshaft out again if you ask me!

[TVR Gary 0]

Cant be bothered, as long as the rev counter is right I dont mind