M2A4 vs U2Q7 transmission ratio, tyre size & mph calcs

[marcusv8thunder]

Just thought Id lay out my ramblings in my head out here since it might be of use to some people.



Prelude gearbox M2A4


(1)3.307 (2)1.950 (3)1.360 (4)1.034 (5)0.787 DR 4.266


Stock steelie tyre size 185 70 14 = (1)38 (2)65 (3)93 (4)122 (5)160 mph @ 7500rpm

Current alloy tyre size 215 45 17 = (1)39 (2)66 (3)95 (4)124 (5)163 mph @ 7500rpm

Trackday alloy tyre size 225 45 17 = (1)39 (2)67 (3)96 (4)126 (5)166 mph @ 7500rpm


To get 2nd down to 60mph


Short ratio tyre size 205 45 15 = (1)35 (2)60 (3)86 (4)113 (5)148 mph @ 7500rpm

Ride height drop of 60mm (2.3") Not fisable unless raising suspension to stock height.


Accord Type R Gear box U2Q7


(1)3.285 (2)2.090 (3)1.481 (4)1.071 (5)0.870 DR 4.266


Stock steelie tyre size 185 70 14 = (1)38 (2)60 (3)85 (4)118 (5)145 mph @ 7500rpm

Current alloy tyre size 215 45 17 = (1)39 (2)61 (3)87 (4)120 (5)148 mph @ 7500rpm

Trackday alloy tyre size 225 45 17 = (1)40 (2)62 (3)88 (4)122 (5)150 mph @ 7500rpm


Prelude Gearbox vs Accord Type R Gearbox


Prelude trackday alloy tyre size 225 45 17 = (1)39 (2)67 (3)96 (4)126 (5)166 mph @ 7500rpm

Accord trackday alloy tyre size. 225 45 17 = (1)40 (2)62 (3)88 (4)122 (5)150 mph @ 7500rpm


Conclusion

Prelude box is too long to simply shorten slightly by dropping tyre size for track use.
Accord Type R box has a much better set of ratios for the track but 5th gear for daily driving is 54mph @3000rpm compared to 60mph @3000rpm for the Prelude.
Since the Accord F Series 5th gear swap would be too long of a gap for the Accord Type R 4th gear, a compromise maybe is using the Prelude 5th gear in the Accord Type R box.

Reality for now

I will probably just use an Accord Type R gearbox and not bother with the 5th gear swap, I could pull some fuel useage out of the 3000-3500rpm map range and fuel prices are cheaper currently. So saving is not worth the effort.

[Chrisnick]

http://www.teammfactory.com/gear-calculator
http://honda-tech.com/honda-prelude-...-list-2548441/

I use those two links more often than I care to admit. At least once or twice a week, if not more.

[Lucien]

Damn, 54mph @ 3k rpm would suuuuuuuck for a daily driver. 60mph isn't much better. What's the cruising speed in 5th @ 3k rpm for a m2b4 with the f22 5th swap?

[Flip-Eye]

Your ramblings are useful!

I'm trying to decide on the best trans to upgrade to, specifically which one I want to swap 5th gear over from the H2U5.

Never seen a U2Q7 over in north america, but the T2W4 appears to have the same ratios and LSD.

[Flip-Eye]

Damn, 54mph @ 3k rpm would suuuuuuuck for a daily driver. 60mph isn't much better. What's the cruising speed in 5th @ 3k rpm for a m2b4 with the f22 5th swap?

Based on the 60mph @ 3000 rpm, an Accord 5th

http://honda-tech.com/honda-prelude-...t-2548441/gear swapped into the M2B4 would be around 67 mphs for 3000 rpm.

[Lucien]

Based on the 60mph @ 3000 rpm, an Accord 5th

http://honda-tech.com/honda-prelude-...t-2548441/gear swapped into the M2B4 would be around 67 mphs for 3000 rpm.

Ah, thanks. That seems like it would be tolerable if i could just cruise at the speed limit...but that's tough. lol

[marcusv8thunder]

Your ramblings are useful!

I'm trying to decide on the best trans to upgrade aspto, specifically which one I want to swap 5th gear over from the H2U5.

Never seen a U2Q7 over in north america, but the T2W4 appears to have the same ratios and LSD.

The U2Q7 is from and Accord type r. Doing these calcs made me go on the hunt for one. And now ive just bought one. Its minty fresh check my mrt. I plan to drop it in in the next weekend or so.

You guys have more accord 5th options. Ours are all the same i think. I think an accord 5th gear is a big gap to a accord type r 4th gear. But depends what you do with it. If you drag and*motorway then a long 5th is preferred. If you do track and not many miles then a short 5th is worth it.

[jaykilla116]

interesting i am in the market for a lsd trans for my h22 .
anybody know the main difference between t2u4 and the m2b4 i will be drooping in a cb7. I plan on occasionally drAg use and mostly sport street use.