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Old 12-06-2012, 02:19 PM   #1 (permalink)
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Question: Civic VX P20 Transmission Gearing

Hello Ecomodders:

I am new to the forum and very new to owning a civic VX. I recently purchased 2 civic vx's. (I purchased a red one first with intent on keeping it, but then I purchased a captiva blue vx because I've always loved that blue).

my question is: What should the actual rpms be when you are at cruising speed in 5th gear?

I have done some research and found that most people are around 2200 rpms @ 70mph in 5th gear (which my blue vx does). however, my red VX does that exact speed and rpms in 4th gear...

In 5th gear, the red car is only doing about 1800 rpm at 70 mph and around 2000 rpm at 80 mph.

I have checked the transmissions on both cars and both are stamped P20 as they should be.

Does anyone have an answer to what would be causing the difference?

thanks for the help!

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Old 12-06-2012, 02:49 PM   #2 (permalink)
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Mine the info you're looking for here.

automobile-catalog web site Hondas

Ironically I was looking at the gearing in my 04EX just last night and noticed I have the crappiest tranny gearing available, I could haul a tranny out of a DX or LX of my same model and get much taller gearing. When & if mine ever fails.

Good luck. I'da looked for the answer for you, but you have scant info on years & such to go on for your fuel sippers, so it's up to you to dig for it. Let us know what you find though.

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Old 12-06-2012, 03:14 PM   #3 (permalink)
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Thanks for the link! That just confirms my theory that my red VX has even taller gearing than what it should have stock.

Does anyone have any ideas on how this could be possible?
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Old 12-06-2012, 04:23 PM   #4 (permalink)
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welcome to the site, great choice on the vx i love them.

i can relate i have a 93 vx that will do the 2200 rpms at 70 mph but i just swapped a d15z1 from a 94 vx into my 4 door sedan and that one seems to run at a higher rpm. (not sure the exact rpm as i just got it driving a few days ago) either way its not a huge difference that i have noticed and i concluded they are both the correct transmission for the vx. i thought maybe my catalytic converter was plugged on the 93. maybe i will pull the oxygen sensor out and take a peak.
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Old 12-06-2012, 04:34 PM   #5 (permalink)
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It seems to me that the red VX has the stock trans, and I don't know what the blue one has. By my calculations of the gears and revs the stock VX in 4th gear should rev at about the rate my 98 DX does in fifth gear--in fact the VX should be slightly taller, I think, even in fourth. Is it possible you have an HF trans? Or that some of the gearing has been swapped, such as the HF final drive, or that you have an import VX trans somehow? My understanding is that the P20 code denotes several different transmissions and that you really need to count revolutions to know what you have exactly.
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Old 12-06-2012, 04:55 PM   #6 (permalink)
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Salvage yard tranny

Quote:
Originally Posted by x-tnsiv View Post
Thanks for the link! That just confirms my theory that my red VX has even taller gearing than what it should have stock.

Does anyone have any ideas on how this could be possible?
i've had to replace a transmission in a civic before. The salvage yards have tons of them and sling them around like candy. It took 3 tries before i got one that wasn't worn out--the salvage yard had no problem exchanging when i brought them back, probably sold them to the next sucker. The point is they have lots of them, don't know what they really have. If it looks the same and will bolt in then it "works". Repair shops don't fix them--they are too cheap and plentiful and easy to just swap out with salvage units.
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Old 12-06-2012, 05:45 PM   #7 (permalink)
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My 94 was right at 30 MPH at 1k RPM and I know it was original since it had 27k miles on it when I got it.

2k at 80 sounds crazy. Mine worked out to 3k at 90. Should be 333 RPM per 10 MPH in top gear.

That was on the original 15 year old tires in 2008 at 27k original miles!

First thing I would check on the 2k at 80 car would be that the tach was right. I could be someones frankenstein tranny made from tallest 5th and differential ratios, but I guess it would have to have HF components since the VX was the tallest final drive of any of the later hydro trannies. My knowledge of Hondas is limited, maybe someone else knows how you could get to that tall an overall ratio.

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Old 12-06-2012, 06:14 PM   #8 (permalink)
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CRX HF would be at 1900 rpm at 65 mph.
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Old 12-07-2012, 06:40 AM   #9 (permalink)
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Tell us the rpm vs mph in each gear, 1 through five, compare speedometer with gps unit and idle rpm of each car.
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Old 12-07-2012, 02:51 PM   #10 (permalink)
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Quote:
Originally Posted by arcosine View Post
Tell us the rpm vs mph in each gear, 1 through five, compare speedometer with gps unit and idle rpm of each car.
ok, I will drive it around later this evening and try to get back to the forum with rpm's and mph in each gear.

The vehicle cold start idles around 1000-1100 rpms and once warm, drops to I believe around 600-700 rpms, but I will double check to verify.

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