Speed versus MPG (CRX)

[SVOboy]

Anyway, this is mine, those values might not be correct, but they're the best I can do pre calibration. Just thought some people might appreciate this as I think it is heavily influence by the super-long gearing of the HF tranny.





A table of my gearing:

RPM 1st Gear 2nd Gear 3rd Gear 4th Gear 5th Gear
500 3 6 10 13 15
600 4 8 12 16 19
700 5 9 15 18 22
800 5 10 17 21 25
900 6 12 19 23 28
1000 7 13 21 26 31
1100 7 14 23 29 34
1200 8 16 25 31 37
1300 9 17 27 34 40
1400 9 18 29 36 43
1500 10 19 31 39 46
1600 11 21 33 42 50
1700 11 22 35 44 53
1800 12 23 37 47 56
1900 13 25 39 49 59
2000 13 26 42 52 62
2100 14 27 44 55 65
2200 15 29 46 57 68
2300 15 30 48 60 71
2400 16 31 50 63 74
2500 17 32 52 65 77
2600 17 34 54 68 81
2700 18 35 56 70 84
2800 19 36 58 73 87
2900 19 38 60 76 90
3000 20 39 62 78 93
3100 21 40 64 81 96
3200 21 42 66 83 99
3300 22 43 68 86 102
3400 22 44 71 89 105
3500 23 45 73 91 108
3600 24 47 75 94 112
3700 24 48 77 96 115
3800 25 49 79 99 118
3900 26 51 81 102 121
4000 26 52 83 104 124
4100 27 53 85 107 127
4200 28 55 87 109 130
4300 28 56 89 112 133
4400 29 57 91 115 136
4500 30 58 93 117 139
4600 30 60 95 120 143
4700 31 61 98 122 146
4800 32 62 101 125 149
4900 32 64 102 128 152
5000 33 65 104 130 155
5100 34 66 106 133 158
5200 34 68 108 135 161
5300 35 69 110 138 164
5400 36 70 112 141 167
5500 36 71 114 143 170
5600 37 73 116 146 174
5700 38 74 118 148 177
5800 38 75 120 151 180
5900 39 77 122 154 183
6000 40 78 125 156 186
6100 40 79 127 159 189
6200 41 81 129 162 192


Calculations done here and gear ratios retrieved here!

[SVOboy]

Oh darn, just realized I mislabeled stuff. Y axis is MPG, X should be speed, but it's wrong, speeds are:
30, 35, 40, 45, 50, 55, 60, 65

[Gary Palmer]

On your test, you got better mileage at 55, than you did at 45 and 50. Were you in 5th gear for all of the speeds, or were you in 4th and then 5th?

[SVOboy]

5th gear for all speeds, that might be a bit of a fluke, but I dunno, I'll have to retest that one, I'm fairly confident on all the numbers though just based on what I'm used too looking at every day.

[krousdb]

Were those instantaneous or averaged over a certain distance?

[SVOboy]

Averaged over 2kms.

[krousdb]

haha, you are now officially metricized! He (she) who reports in km is either Canadian or has a SuperMID.

[SVOboy]

I have always preferred metric! Mwahaha.

[thisisntjared]

so 55 is your magic number huh....

[philmcneal]

Originally Posted by krousdb

haha, you are now officially metricized! He (she) who reports in km is either Canadian or has a SuperMID.

i perfer mpg so i blame the american's influence.

[SVOboy]

Originally Posted by thisisntjared

so 55 is your magic number huh....

I'd say 30 is,

[SVOboy]

Thought I'd throw this up for comparison, tall gearing rocks.

[budomove]

Is that graph showing YOUR car's efficiency scale?

Wow.

[SVOboy]

HF tranny FTW!!!

[budomove]

I figure I can get that too, since i just turned in two good tanks of approx 43 and 44mpg. With the hf i should pull off 50mpg in ideal conditions.

Then a belly pan!

[SVOboy]

Too bad you have no instantaneous FE display!

[budomove]

Yeah, too many mods to set the car up to take instrumentation though.

[budomove]

On your graph, the diff in mpg b/w 50mph and 60mph is almost 10mpg. That's a lot! I will definitely try to keep the speed down whenever safe, and see if I can get 60mpg on the highway doing 50mph.

[SVOboy]

That would be quite the good. I'm kinda wondering what I will get on my little road trip tomorrow.

[budomove]

Godslow! (the fe modified good luck expression)

[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.