M2F5 Gearbox needed anyone? £35

CrunchyAdams82 · Post by **CrunchyAdams82** » Wed Nov 20, 2013 9:30 am

Ahh, I see; 5th gear is longer - not shorter. Good info, thanks Merlin.

Post by **Merlin** » Wed Nov 20, 2013 9:40 am

Sorry you were on about 5th gear, I was talking about final drive. You are correct, the M2F5 does have a shorter 5th gear.

The ratio's K30DPC had put up are the wrong ratio's (lots of lists wrongly state the 5th gear and final drive numbers).

CrunchyAdams82 · Post by **CrunchyAdams82** » Wed Nov 20, 2013 10:07 am

So what are we referring to when we talk about final drive?

Having played Forza Motorsport on Xbox, I know that when you increase or decrease the final drive, it lengthens or shortens all 5 gear ratios.

But what does that mean for our different gearbox types?

For example; does it mean on the M2F5 the final drive is longer (higher top-end effectively), but within that spectrum, it will accelerate faster than say an M2A4?

I'm confused..

Post by **Merlin** » Wed Nov 20, 2013 10:36 am

Sorry I confused the matter

The M2F5 has the same ratios for 1st to 4th as the M2A4/M2b4 but the M2F5 has a different 5th gear (like you correctly said). Some lists put the M2F5 as a 4.266 final dive whereas it is actually 4.062 which means the M2F5 will accelerate slower than the M2A4/M2b4 in every gear apart from 5th (assuming engine power is the same). You have to wonder why Honda chose this as by the time you get to 5th gear the acceleration party is over

Perhaps it was just too slow in 5th with that final drive

M2A4/M2b4 on the left and in red
M2F5 on the right and in blue

The more shallow the line the quicker the car will theoretically accelerate.

CrunchyAdams82 · Post by **CrunchyAdams82** » Wed Nov 20, 2013 10:43 am

Ok, so I assume the M2F5 will only accelerate slower in gears 1 through 4 because the final drive is longer. Right? Because the ratios of these gears are identical to M2A4/M2B4.

But, equivalently, it will accelerate faster in 5th because it's 4th & 5th ratios are closer together than in the others?

Is that correct?

Post by **Merlin** » Wed Nov 20, 2013 10:52 am

CrunchyAdams82 wrote:Ok, so I assume the M2F5 will only accelerate slower in gears 1 through 4 because the final drive is longer. Right?

Yup the gear ratios are the same but the final drive is different.

CrunchyAdams82 wrote:But, equivalently, it will accelerate faster in 5th because it's 4th & 5th ratios are closer together than in the others?

How close the ratios are to one another only really has a bearing on the amount of rev drop you get between gears. The M2F5 accelerates quicker in 5th because the shorter 5th gear offsets the longer final drive.

I don't know the exact calculation, I think @Alex is the man to calculate it out.

The M2F5 is the gearbox you want if you are doing a gearbox build. Both Rich from Performance Autoworks and I use the the M2F5, minus the OEM final drive and diff of course

If my M2F5 eats itself and you still have this I will buy it off you

CrunchyAdams82 · Post by **CrunchyAdams82** » Wed Nov 20, 2013 12:02 pm

Good stuff, thanks for explaining all that.

CrunchyAdams82 · Post by **CrunchyAdams82** » Thu Nov 21, 2013 10:33 am

Anybody need this then?

CrunchyAdams82 · Post by **CrunchyAdams82** » Fri Nov 22, 2013 5:39 pm

Ok, £40. Let's do this.

K30DPC · Post by **K30DPC** » Fri Nov 22, 2013 6:40 pm

+ postage?
if posted then I take it