USA

I know the LS fifth and final drive are the highest geared stock for the b series but does any aftermarket or other honda gear work as an even higher fifth gear? I'm looking for top cruising speed on the highway without wasting gas.

tony_2018

If you're looking for custom gear sets you can check synchrotech. You can also check mfactory too I guess.

MotorMouth93

iTrader: (1)

Pulling the trans and installing expensive custom gears for marginal, theoretical fuel economy improvements based on nothing but the very crude idea that longer gearing means better mpg doesn't seem worth it to me. You'll have to drive that car for many years before you make back the money you spent on the gears and labor in fuel savings. And that's only if it actually yields better fuel economy, which it likely won't.

Honda picked the LS 5th gear ratio to optimize fuel economy, if making it longer were truly better I think it would have come that way from the factory. It's a balancing act, if you make the gear too long you'll have to give the engine more gas to maintain speed and end up with worse fuel economy, if it's too short you won't get optimal fuel economy either. Different speeds also have a different optimal gear ratios. Honda engineers are far better equipped to tackle that problem than we are as they were the ones who designed the motor and spent many many hours tuning fuel economy and performance.

If you have unlimited access to a dyno for testing and are capable of cutting your own gearsets then sure you might be able to make an improvement after a lot of testing for very specific use cases, but otherwise you're basically taking an expensive shot in the dark.

USA

Yeah thanks for the info I'm looking into a turbo setup making around 300hp. So I'm probably just gonna end up putting a much taller tire on it to give me a little more top end.

wunfstgsr

Well you will find even with the tallest gear when boosted your gonna burn allot fuel regardless! At the end of the day your gonna wanna get into boost driving even in 5th gear! and trust me 11.5 to 12.5 AFR is gonna suck that fuel right out the tank! So your chasing a ghost bro! boost and saving fuel don't mix! If it was a daily driver all stock used for long freeway trips than that's the only reason you should look into changing that gear for better MPG, MotorMouth93 said it the best!