Automatic RT4wd/ OBD1 compatibility question

I can't seem to find this topic covered, I searched first, really I did!

My question/topic of discussion: Is there any reason why the automatic transmission in my '91 RT won't work with a d16z6? I don't know how much of the tranny is electronically controlled, whether the extra RPMs will confuse it, etc. Will it work or no?

And, do I need an auto trans ecu in obd1?

Comments

  • i was at the junkyard once and i found a auto RT. i took off the ecu and it was a pm6. the EX sedan auto has p2j and it has a wire for transmission solenoid. people use this ecu for 1 wire vtec obd0 set up. i was wondering why the auto RT has pm6. pm6 is for a manual i believe. i dont remember if the auto RT has tranny solenoid but i believe it should.

    i thought i should share my observation and maybe it will help.



    wagon.....................................4ever...............
  • CharbCharb Administrator
    Frank (akiraboy) had a Z6 w/ auto RT.

    For the life of me I cannot remember the ECU setup he was running. I think he was running a piggy back with OE ECU. Maybe it was a Z6 ECU. You might dig up his thread. At least it's a place to start.

    Good luck!
  • bam-bambam-bam Council Member
    Thanks. Do all z6 blocks have the holes for the intermediate shaft? BabyJ pointed out that Luke/s WagonAttack car is a z6...

    Think it's worth the obd1 conversion, or just keep the a6?
  • now what...
    real science...?
    :mrgreen:
  • CharbCharb Administrator
    bam-bam wrote:
    BabyJ pointed out that Luke/s WagonAttack car is a z6...

    But his is a manual tranny.

    I want a Z6 myself. I don't know that I'm gonna have the money to do it the right way, so I may just do a replacement A6 or DOHC ZC for this year.
  • bam-bambam-bam Council Member
    running z6 w ecu $350...
  • CharbCharb Administrator
    bam-bam wrote:
    running z6 w ecu $350...

    Where!?
  • bam-bambam-bam Council Member
    Charb1618 wrote:
    bam-bam wrote:
    running z6 w ecu $350...

    Where!?

    Now it's in the back of my wagon. I actually paid $425 to include a complete rebuild kit, a spare head and intake manifold, and distributor.

    This particular engine does have the intermediate shaft mounting holes drilled and tapped :)
  • CharbCharb Administrator
    Sadly I'm in Spokane which rarely has anything for sale locally. I keep hoping to find someone parting something out, but no luck (yet).

    We do have a local JDM distributor though. So that's the route I'll likely go.
  • HaydzHaydz Moderator
    The bolt holes and landing should be there on the Z6 block, but the holes are not always tapped.

    No idea on the ECU sorry, but i very much doubt the ECU has any hold over the box apart from lockup.
  • bam-bambam-bam Council Member
    Thanks. I've got a P28 from an auto car on the way. I was shopping for a P28 for my wagon anyway, so I'll just get this one chipped.
  • HaydzHaydz Moderator
    Oh and Frank had a mini-me - D16A6 bottom end and Z6 head.
  • bam-bam wrote:
    I can't seem to find this topic covered, I searched first, really I did!

    My question/topic of discussion: Is there any reason why the automatic transmission in my '91 RT won't work with a d16z6? I don't know how much of the tranny is electronically controlled, whether the extra RPMs will confuse it, etc. Will it work or no?

    And, do I need an auto trans ecu in obd1?

    I'll answer what I can. First, RPM's will not "confuse it". I get what you're trying to ask and I know enough about engine management to tell you that it's not a problem. Second, yes, OBD1 needs an auto specific ECU and a separate TCM.

    The OBD1 automatics are partially electronically controlled. 96+ are fully electronic. I completely forgot everything I knew about the earlier autos except that they were stronger and better than later generations which were made to slip more for driver comfort.

    Contrary to popular opinion on forums, Honda automatics are great. What limits them performance-wise is that they have four gears vs the standard five, and overall the long gearing just kills acceleration on our low displacement, high RPM engines when compared to a VTEC manual trans.
  • The_HeadThe_Head familEE
    Contrary to popular opinion on forums, Honda automatics are great. What limits them performance-wise is that they have four gears vs the standard five, and overall the long gearing just kills acceleration on our low displacement, high RPM engines when compared to a VTEC manual trans.

    Yeah, I always wondered why nobody "built" their automatic to handle a whole lot of power. I wonder how much power a stock auto could take.
  • bam-bambam-bam Council Member
    OK, so if I use an auto-specific P28, but the stock RT auto tranny...The trans doesn't need the TCM, but the ecu still needs/wants to see it?

    I guess what I meant about the "extra RPMs" is that the transmission shifts well before VTEC would engage (I think?). Did the newer, EC trannies hold shifts longer?
  • Use a manual P28. The auto P28 will throw codes.

    If you have the throttle all the way down it will go all the way to red line.

    My friend had a auto 89 RT4WD turbo daily driver. It made close to 200 whp. It warped the head and then he sold it to me and I parted it out. But the auto held just fine.

    What's to build? TCI makes a high stall converter and upgraded clutch packs. Most likely discontinued. I agree that there's no reason to use a Honda auto for a race-only application. But if it's a Toyota Supra then that's something else.
  • ragenasianragenasian Moderator
    I also have an Auto P28 ECU and found this little writeup on converting it to a manual ECU. Don't know if this helps you BAM but I might give it a go since my ECU was free.

    http://www.hondacivicforum.com/forum/sh ... hp?t=65008
  • it's been a while...so let me say something stupid (again)

    hi-lo gearing...

    : )))


    you can only kill me once...stop it
    :mrgreen:
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