Speed versus MPG (CRX)

[SVOboy]

Originally Posted by Darin

Actually I forgot about it, but yeah, that's a crazy graph (Speed versus MPG (CRX))

If it's OK with you, I might fix it up a bit and post it on my site with the others. But I want more methodology info: what were the temps, and were the readings averages of bi-directional runs, or one-way? All repeated on the same stretch of road? Other cars around? (I cancel runs where I'm in another car's wake - I don't mean drafting).

Anyway, I don't recall any of that stuff. I'll have to find a better stretch and redo it. The only really good stretch is loaded with cops though, so I guess I'll have to be careful. Dunno when I'll get it done but I surely will, since you're such a nice fella and I likes to helps.

[MakDiesel]

I really need to install my HF tranny into my '85 CRX Si...currently it runs a stock Si 5-speed w/ HF 5th gear, which is similar to a bandaid...should just go with the surgery the first time around and get it over with...

[MetroMPG]

Are the Si / HF differences only in the gear ratios? Or are there final drive differences too? If it's just gears, the 5th gear upgrade is a nice compromise.

[MetroMPG]

Oh, and Ben, don't redo the graph just for my benefit. Unless you feel a burning need to gather new stats, I'll just post the one you've got. Not a big deal.

[Gary Palmer]

Their is a pretty large difference that's a function of the final gearing. The DX and SI both have a 3.88 final, while the HF is 2.95, for non-california. The VX, CX are 3.25, just as a comparison. The bulk of the rpm difference's between the two is largely the final, much more than the O.D. gear. That's a part of what persuaded me that a transmission change to an HF would probably give me more improvement than any other single thing I could do. Haven't been able to find an HF available, yet, but I'm also trying to get it for the kind's of prices SVOboy has been able to get thing's, so I figure I just need to give it some time.

[thisisntjared]

Originally Posted by MetroMPG

Are the Si / HF differences only in the gear ratios? Or are there final drive differences too? If it's just gears, the 5th gear upgrade is a nice compromise.

the final drive is totally different on the hf.

[SVOboy]

I think all the questions have been attended to, woohoo.

[thisisntjared]

for all your obd1 civic tranny queries:
http://home.cinci.rr.com/mistab0ne/tranny.html

[white90crxhf]

Originally Posted by Gary Palmer

Their is a pretty large difference that's a function of the final gearing. The DX and SI both have a 3.88 final, while the HF is 2.95, for non-california. The VX, CX are 3.25, just as a comparison. The bulk of the rpm difference's between the two is largely the final, much more than the O.D. gear. That's a part of what persuaded me that a transmission change to an HF would probably give me more improvement than any other single thing I could do. Haven't been able to find an HF available, yet, but I'm also trying to get it for the kind's of prices SVOboy has been able to get thing's, so I figure I just need to give it some time.

the SI tranny has a 4.25 final drive. i did the math on the differential myself just to make sure. there is a huge difference in rpms @ 65mph.

[SVOboy]

Updated my grizzaph.