Guys

Last night I picked up a complete Z6 for my 89 CRX si.

Initially my plans was to just swap the block/head in the car for a trouble-free swap in which I'd gain a motor with significantly less miles (A6 had 210k) and I'd get a little more pep for the same price (I have a friend who's buying my A6 and I'm installing it in his car for 400)

I have done this swap before and from what I remember, this is all thats needed to be done in order to put the Z6 into an Si (MPFI model)

Change Z6 crank pulley to A6 crank pulley
Install A6 alternator on Z6 block
Install A6 upper water neck on Z6 block
Exchange Z6 driver's motor mount with A6 mount
Use Si tranny
Exchange Z6 intake manifold/injectors for A6 intake manifold/injectors
Exchange Z6 exhaust manifold for A6 exhaust manifold
Exchange Z6 Dizzy for A6 dizzy
Use PM6 ECU and run a VTEC controller or RPM activated switch
Use A6 flywheel/clutch with A6 trans on Z6 block
Exchange Z6 4-wire 02 sensor with A6 02 sensor

(someone please add in details if I've forgotten something)

Now enteres my dilemna

I purchased the whole Z6 setup for 400 dollars. It was a little more than what I wanted to pay, but it came with an aftermarket header (obviously for an EG), is really clean, and has ALL of the Z6 stuff (dizzy, alt, manifold, injectors, etc)

I got to thinking I may want to go OBD-1 so I can take advantage of the P28 ECU. It would alleviate the headache of an RPM activated switch, and I would be able to run the correct redline (I believe limiter is set at 7500 on a P28) I would also be able to run all the correct Z6 stuf like the intake mani, sensors, dizzy, etc but my question is, is it REALLY worth it, as I can see myself dumping an additional couple hundred dollars in an obd-0 > obd-1 conversion harness, P28 ECU, 4-wire o2 sensor, etc.

I only use this car to drive back and fourth to work every day, but I wanted to put something with lower miles in the car and Z6's are pretty readily available. I have no need to try and make this car blazing fast because my actual project car I just garaged for the winter was making 540rwhp....

I would like to take advantage of the 7200 redline on the Z6,but I know the PM6 ecu is only going to give me 6500. I have not done much research on PM6 ecu tuning, but I know some of them are 'chippable' and some of them are not. Are people offering services such as raised rev limit, and P28-esque fuel maps on these ECUs?

It all boils down to this..

1. Spend an extra 2-300 on parts to be able to run OBD-1, but for what advantages?

2. Spend 20-30 dollars on an RPM activated switch, and possibly 20~ on an EPROM chipped for higher redline (may have to buy a different PM-6)

 

I honestly think its better to go obd1, you will be running the eng VERY lean in vtec with a rpm switch. Thats my 2 cents...

 

+1

 

+1

 

As I stated earlier, I have not dove very deep into the Z6/ECU/PM6 tuning arena, but I pick up things fast.

When you say lean, how lean are we talking? And what is the limitation/bottleneck of the fuel issue? Is it lack of injector, lack of correct fuel maps?

Since the motor currently only has the ability to turn 6500rpms, is the lean-ness going to be too much of a factor?

Lastly, the swap MUST happen this weekend. My friend MUST have a car (his A6 is blown up) to get around to work and stuff in and I promised him I would do it, and its my only weekend for a month that I can do the swap. Is it possible to limp the car around for a week using the Z6 intake manifold, but just switching to the Si injectors. I would obviously need to use the dizzy/altnernator until I got the obd-1 stuff, but I would really prefer to not have to seperate the intake manifold from the block once the motor is in the car. The dizzy/alt are easy switches.

 

go with the obd-1 conversion bacause the pm6 ecu wont allow the change of vtec to work properly on the rpm switch u wont have the extra fuel going into your motor when vtec kicks .....well good luck with this ...im doing the same exact thing on my 90 crx si

 

To answer your question is it really worth it.....YES it's worth it and really the only right way to do it.

The A6 distributor will not work on the Z6. The A6 manifold is much worse for performance than the z6, don't use it. Do not use the A6 pulley on the Z6. The Z6 pulley has a harmonic dampener and needs it, the A6 pulley does not.

Just use all of the Z6 stuff and modify your harness. A lot of people are scared of the wiring, but it's not that bad. Soldering is super easy. You'll need obd1 injector plugs and distributor plugs

distributor - in between 10 and 15 wires
injectors - 8 wires - delete the resistor box
Vtec - 2 wires run to the ECU
O2 sensor - run the 4 wires straight to the ECU
alternator 4 wires...or just use the obd0 one.


then just buy a jumper harness and a P28...done.

 

Go aheah and pull the motor, lay the harness out on a work bench and go crazy.

Also, why would you use the A6 exhaust manifold?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tw1n Turb0 Z &raquo;</TD></TR><TR><TD CLASS="quote">
When you say lean, how lean are we talking? And what is the limitation/bottleneck of the fuel issue? Is it lack of injector, lack of correct fuel maps?

Since the motor currently only has the ability to turn 6500rpms, is the lean-ness going to be too much of a factor?

</TD></TR></TABLE>

its not that the pre-obd injecotrs cant supply the fuel flow, its that the ecu does a lot to maintain the engines integrity once the other cam profile comes into use.

im not sure if anyone has actually sat there with a wideband and figured it out, but it cant be healthy for it given the agressive nature of the other profile....

when my brother did a mini me with a z6 head for this chick he used rywire.com stuff and it was mostly plug and play.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by doublethink &raquo;</TD></TR><TR><TD CLASS="quote">its not that the pre-obd injecotrs cant supply the fuel flow, its that the ecu does a lot to maintain the engines integrity once the other cam profile comes into use.

im not sure if anyone has actually sat there with a wideband and figured it out, but it cant be healthy for it given the agressive nature of the other profile....</TD></TR></TABLE>

it's just like running an aftermarket cam and being untuned. It's just not going to make power.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by thehatchninja &raquo;</TD></TR><TR><TD CLASS="quote">it's just like running an aftermarket cam and being untuned. It's just not going to make power.</TD></TR></TABLE>

ok cool, good info. ive just always known from people on here it was not a good idea, but never exactly why.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by thehatchninja &raquo;</TD></TR><TR><TD CLASS="quote">To answer your question is it really worth it.....YES it's worth it and really the only right way to do it.

The A6 distributor will not work on the Z6. The A6 manifold is much worse for performance than the z6, don't use it. Do not use the A6 pulley on the Z6. The Z6 pulley has a harmonic dampener and needs it, the A6 pulley does not.

Just use all of the Z6 stuff and modify your harness. A lot of people are scared of the wiring, but it's not that bad. Soldering is super easy. You'll need obd1 injector plugs and distributor plugs

distributor - in between 10 and 15 wires
injectors - 8 wires - delete the resistor box
Vtec - 2 wires run to the ECU
O2 sensor - run the 4 wires straight to the ECU
alternator 4 wires...or just use the obd0 one.
.</TD></TR></TABLE>

Wiring does not scare me. I had a 90 CRX DX i performed the OBD-0 Z6 swap and an MPFI conversion on. I had a DX harness and an Si harness and I did all the modifications myself. Fired right up the first time and ran like a gem.

The A6 dizzy DOES fit up to the Z6 head, proof (courtesy of my DPFI &gt; MPFI Z6

 

The aftermarket header that is on this motor currently would not bolt up to the CRX Cat.....I dont believe any EG exhaust manifold will bolt up to an EF cat. The lenght is different

 

I did my Z6 a few years back with a complete obd1 conversion. Been running great for 3 years w/o issues.

 

well if you already know how to do everything and have your mind made up then what are you asking?

Go do your ghetto Z6 swap.........Actually i've seen one guy with VTEC on a switch, and his car was actually pretty fast.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by thehatchninja &raquo;</TD></TR><TR><TD CLASS="quote">well if you already know how to do everything and have your mind made up then what are you asking?

Go do your ghetto Z6 swap.........Actually i've seen one guy with VTEC on a switch, and his car was actually pretty fast.</TD></TR></TABLE>

Who said I had my mind made up? I created this thread to weigh the differences between the two methods of doing a Z6 swap. My previous post regarding the dizzy was just providing fact that the A6 dizzy does directly fit into the Z6 head.

 

pick up a test pipe

 

go and try to put that a6 dizzy on the z6 engine, 1 you will never get the timing right 2 you will have to cut the holes in the dizzy to allow for adjustment, i had my d15b running with the a6 distributor on odbo this is a waste of time, im not trying to be a dick but you will throw that distributor across the windshield trying to get it to work right. spend the money and do it right, i had to wait three days and missed some work because i was trying to be cheap when i should have just done it right before i got my motor and had it fired up early instead of later..my suggestion is to go obd1, if you try to go obdo and get stuck on the dizzy pm me

 

I can handle the OBD-0 dizzy stuff........this would be the 3rd Z6 swap I've done in a CRX so far....

I never said the dizzy was an exact fit. You need to notch out one of the posts with a grinder/dremel. The timing isnt really that tough either. Once the car is running, a timing light does wonders.

I do want to to OBD-1 but the issue that I have now is I have to have the Z6 in my car this weekend (as its my only car right now) and I'm not going to be able to find a P28 or a harness and have them delivered by the weekend. I promised my friend that I would install my A6 in his car this weekend.

 

i just recently converted to obd1 in a d15b vtec. i have to say it was easy with the rywire kit but overall i'm not happy with the outcome.
i haven't figured out what the problem is exactly but after i did the conversion my engine seems to bog a little when i give it throttle and takes a while to get to high rpms if i rev it, all this never happened when i was obd0.
i have no codes and i adjusted a few things like the tps and dizzy timing to 16 degrees, and i have yet to get vtec working even though i wired up everything correctly.

 

From personal experience yes go OBD1. I had the same swap in my 89 CRX Si and for a while I used the PM6 ECU with VTEC controller (field's) and it never felt that great. Then I had a friend who let me borrow his PR3 ECU with the knock sensor code removed. It ran better with this but ran a little rich for my taste. Finally I converted to OBD1 and used the P28 ECU and it ran perfect and actually idled better than with the A6 and PM6 and just felt better throughout the band.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HondaPartsHero &raquo;</TD></TR><TR><TD CLASS="quote">From personal experience yes go OBD1. I had the same swap in my 89 CRX Si and for a while I used the PM6 ECU with VTEC controller (field's) and it never felt that great. Then I had a friend who let me borrow his PR3 ECU with the knock sensor code removed. It ran better with this but ran a little rich for my taste. Finally I converted to OBD1 and used the P28 ECU and it ran perfect and actually idled better than with the A6 and PM6 and just felt better throughout the band.</TD></TR></TABLE>

Cool, glad to hear

UPDATE: The car is definately going OBD-1. I just scored this gem on ebay

http://cgi.ebay.com/ebaymotors...%3A11

5spd P28 + OBD-1 plugs so I can make my own harness

 

nice

 

I dont know how different a Z6 head is from the Y8 head but im running all my obd0 stuff on my Y8 head just fine. (91 civic 4d EX)

 

I would say if you really wanted to stay OBD0. You could run a chipped PM6 for the proper air/fuel and timing and then get a rpm switch to activate VTEC.

And by chipped I mean Turboedit not a ebay chip.