Mk2 MMT to Manual into Mk1 Aygo

[Streaky744]

So little update on my lads race car, in three meetings it fried the clutch but found the gearing to be to long to keep the car singing in vvt range coming out off corners. ( short oval race track) 

So bit research mk1 aygo has a diff ratio off 3.55 however the mk2 aygo mmt box has a diff ratio off 4.22.  As technically the mmt box is the same as manual I got hold off a 2020 mk2 mmt box and swapped the casing and clutch release fork to make it a manual box n fitted it to my boys mk1. 

1st and 2nd gear ratios are identical between mk1 and mk2 manual and mmt boxes only the diff ratio differs and 3rd gear onwards, He only races using 1st and 2nd so hoping the higher diff ratio will increase acceleration out off corners to make the car more responsive. Will find out Sunday. 

On a plus note this is a very easy swap if you want to retro fit an mmt box to make it into a manual and fit the 15 inch wheels to keep the gearing right on a mk1. 

We have  185 / 55 /14 tyres on  yaris wheels on front off the race car with 20mm spacers to keep rolling radius within 2mm off the stock 155/65/14 tyres but with much more grip. 

 

[flash22]

MMT, it just a manual box (internally) with a load of junk bolted to it, Mk1 manual gearboxes are C551 C552 and C553 (MMT is C551A), Mk2 Manuals are C550, C551 (MMT is C553A 4.294)

you should pick up some gains

any problems with driveshafts ? Not sure, you may need to swap the inner drive cups, but that may be a yaris thing

[Streaky744]

Was a straight swap ( outer casing and clutch release arm). Internals are same regards output for shafts.  No issues with shafts.

The gains on track where immense. Raced today and car went so well. Made a huge difference. Running 14" wheels ( yaris ones) on driven wheels with 185 55 14 tyres ( 2mm rolling radius difference from 155 65 14) but lot more grip. with 20mm billet spacers,  car so responsive, pulling strongly out off corners. Gone from mid pack to front runner. Know it not really any good for road use but on short oval makes big difference especially in a class for kids where mods are very limited.