trans problem - Honda Prelude Forum

bluebearchris · 06-04-2010, 11:14 PM

I have a 91 prelude with JDM B20a engine on it..and i think i dont have the right
Trans because with Im driving on the freeway on fifth gear.. my RPM r in 5000..is that normal..

Colfax · 06-05-2010, 12:29 AM

It depends on what speed you are going. I doubt you have the wrong transmission, since only 3rd gen Prelude transmissions will work in the 3rd gen with the b20a. You most likely have a d2a4 transmission, which was the stock tranny for all 90/91 Si and 2.0Si. I'm not sure what the 90 2.0S had for a transmission, but that's irrelevant since you have a 91. Look at the transmission housing, near the starter. There should be an identification sticker located identifying the transmission. Here is a pic for reference. It should say either d2a4, or d2j5, or d2j3. The yellow arrow is pointing to the sticker...

ninjalo161 · 06-08-2010, 07:33 AM

i personaly have a 89 prelude and mine revs close to 3-3.5 i like it really helps to pick up well at high speed in fith what speed do you do down the highway that will obviously affect the revs

ninjalo161 · 06-08-2010, 07:39 AM

and sorry if this is of topic but colfax do you find you have more pick up with the air filter at the front of the bay like that becuse mine is at the back right next to the injexter and runs down inbetween the crack in the enginge i always thort thats a **** place to put it becuse is going to get all hot air and we all know cold air has more oxigen
but thats where it was when i brought my car

Colfax · 06-08-2010, 10:45 PM

That's actually not my engine bay. But you will find the most gain from a true cold air intake. Any intake that has the filter in the engine bay and does not pull cool air in from outside the engine bay is not a true cai. I would have to say that the stock intake would actually be better than the one in the picture I posted, because the stock intake is actually a cold air intake.

bluebearchris · 06-09-2010, 12:26 AM

THANKS FOR THE TRANSMISSION CODES..THEY WILL HELP ME A LOT...U think its because i have a JDM transmission and motor ?

Colfax · 06-09-2010, 07:53 AM

You never did say what speed you were going when you are seeing 5k rpms.

I've read that the d2a4 has a shorter 5th gear than the other two transmissions. I don't think it has anything to do with the tranny being JDM. The engine has nothing to do with how many rpm's you are turning. That is totally dependent on the gearing of the transmission, differential, and tire size.

bluebearchris · 06-09-2010, 09:49 PM

At 5k rpm in going like 80mph..in the freeway....and tire size..I have 215/45/R15..front and back..

Colfax · 06-09-2010, 10:46 PM

I don't have a chance to hit 80 mph in my area. Highway speeds here are 60 mph, and the nearest freeway is more than an hour away. Of course, I exceed 60 when passing someone. But I haven't looked at the tach lately to see how many rpm's I'm turning. I can tell you at 60 mph I'm turning a hair over 3k rpm's. How does that compare to yours?

bluebearchris · 06-10-2010, 09:18 PM

very body drive fast in the freeway..like 75-80..mph..at 60mph im at 4500rpm..

Colfax · 06-10-2010, 11:05 PM

Yeah, that does seem wrong. I checked today, and at 80 mph I'm turning about 4200 rpm's. I'm wondering if your speedometer is maybe wrong, or you have a problem with your tach. Did you have a chance to check the tag on the tranny so see which one you have installed?

bluebearchris · 06-11-2010, 08:54 PM

Yea..I change the cluster...twice..the first cluster i got at the junkyard..and the second one..i got it at honda....Does my turbo got to do anything with my autometer?.because im running 10psi..

Colfax · 06-12-2010, 01:12 AM

Sorry man, I know next to nothing about turbo. I've never owned one. But you still didn't answer my question about whether or not you've checked the transmission id tag.

bluebearchris · 06-13-2010, 12:02 AM

I don't have transmission tag..i guess the old owner change the transmission....So on a USDM....2.0 si come with what transmission..?

Colfax · 06-13-2010, 01:35 AM

Your 91 would have come stock with a d2a4. All 5 speed 90 and 91 ludes came with that transmission.

bluebearchris · 06-13-2010, 01:27 PM

Thanks for the info...

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