nitrodragster

Hey all. I have a sratch built dragster with mrx4 running gear and im trying to source a 15 tooth first gear. Is there one that fits from another brand? HPI??? I have heard Delta do aftermarket stuff. do they have anything?
Thanks in advance

Corse-R

You can fit a Evolva/Delta XP4 first gear, but you need to do some work by yourself in order to fit it correctly.

First, from an old Mugen 1st gear pinion, you need to get the inner lip that separates the 1st from the second gear pinions. This involves serious work with a dremel, because you need to cut it and ground it parallel (this one is just a matter of pure patience.

One time you had the washer, you need to remove the inner lip of the pinion on the Evolva/Delta XP4. This is smaller than the one you need for the Mugen and this separation will be provided by the washer you crafted before. Sorry I do not have photographs now, but on the MRX-4R thread you will find some info when I did this some time ago.

Be advised that a 15 tooth is somewhat extreme for a first gear, roughly this will provide you round 8.1:1 ratio, try first with a 16T who is available easily from Mugen before starting to do this. Could create problems with the second gear meshing or gear selection.

latemodel13

iTrader: (101)

You can fit a mtx3 15 tooth on it but it's narrower and it will not hold up as well. If drag racing it will probably last you awhile.

nitrodragster

Thanks for your help guys. With a 15-50 combination it will give me a ratio of 7.39. 15-50 = 3.33 lay shaft 18 - 40= 2.22. 2.22 * 3.33= 7.4

atm it is 6.93. it is a fair bit overweight and a bit of a slug off the line. there is only so much i can put in the clutch before it drives through it. If i lower 1st i can back the clutch of and get it to lock up a bit better. I dont want to mess with second gear to much thats why i dont want to change the lay shaft if i can get away with it. I may have to but i am just looking at all my options.. just need to get after it more in the first half the track.

Would i just be able to machine up a coller or spacer to fit in behind the gear. I have access to most of the gear needed.

TrickPonYracing

iTrader: (2)

the mtx 3 way is easyer to go i used axle spacers to shim it1 5/48 we have a super high bite track it's new s 3 grade asphale

cdelong

iTrader: (12)

there is some kind of problem if 16/50 first is not enough?

What clutch set-up are you running? flyweights, spring, shoe, clearances and spring tension....

pipe, fuel, engine, plug, head clearance??