I have a somewhat rare and original 1993 Prelude VTEC model that was rear-ended by an F250 with massive unibody damage and all panels trashed. However, the car can literally drive down the road just fine with the H22 running beautifully.

I also have a 1996 Prelude S model with an average 2.2 I believe it must be an F22. But the car runs and drives well (although no ABS like the 1993 VTEC model.)

Both of these models have standard 5-speeds -yes.

I would like to swap that 1993 vtec into the 1996 S. However, I have some questions.

1. The gear ratio's into 1996 are higher than the ones in the 1993. Someone told me the higher-gear ratio tranny won't hold up to VTEC rpms and/or power and I should change both tranny and engine. Is this true? I would rather keep the higher geared as I do a lot of HWY cruising and the 4000 rpm cruise engine speed of the 1993 VTEC model was always a little fatiguing to me.

2. What is the simplest, lowest-cost method to get that VTEC to properly work in that OBD2 setup? I have seen mentions of a OBD2 to OBD1 conversion, piggyback ECU's, etc. I live in Eastern WA State and HAVE NO SMOG REQUIREMENTS and can do whatever is practical to get 'er done.

3. Exhaust manifolds and any other pieces are no problem - I have the complete running drivetrain for the 1993 VTEC model. I can transfer anything needed.

I originally had a fantasy of finding a reasonably-priced 1993 to 1995 VTEC model with maybe a tired or blown-up motor for an easy swap but I now see how rare those are. Most people bought S or Si's or even 4WS with automatics.

If anyone can greatly condense my focus down to some practical solutions and answers, I would be grateful. I loved that 1993 VTEC before I lent it out to a good friend who was rear-ended by a drunk driver (the friend wound up with some neck/back problems but otherwise the car beautifully protected the driver.) I even love my 1996 130hp version but would love to give it more zip.

 

Hi welcome to the forum! Good luck on your project! I'm not entirely sure of the differences between the 1993 and 1996 model. I would assume the 1996 model is potentially OBD2? vs the OBD1 of the 1993? The h22 engine should fit the 1996 model just fine, however.

 

Just use conversion harness

 

If I were to do that swap, I would pull the drivetrain from both cars, swap the oil pump, distributor, and harness to the vtec engine, as well as do a new timing belt setup, water pump etc, and use the 96 transmission. The only things needed would be a vtec wiring addition, and the vtec ecu from a 96, which can be rare. Otherwise, do a full obd1 swap, and use everything from the 93 engine, just use the 96 trans for the longer gearing.

 

Thank you for your input. Who sells the conversion harness? What exactly is getting converted and where does the harness get installed? Also, I am assuming my '96 ECU won't properly operate a VTEC engine so would I move the 93 ECU over or apply some other solution like trying to find an extremely rare 96 VTEC ECU?

 

The '93 VTEC has only 130K and has always run synthetic. The 96 has over 200K miles. I'm not sure of the advantage of swapping oil pumps.

The water pump and timing parts are relatively low miles on the 93 Vtec motor but I would probably take your advice and change them anyhow while the engine is accessible. I fire up that beauty from time to time to ensure she keeps running well.

I have seen that '96 VTEC ECUs or any year VTEC ECUs are hard to find so definitely had considered changing out everything from the 93 to the 96.

Unless someone has first-hand info against the VTEC with the taller gears, I would definitely keep the 96 tranny which is in beautiful shape. I'm sure I could always find the right gear while driving to keep that VTEC in the proper power band when the power was needed. I can verify that the '93 would do 140 mph at redline. I wonder if it has enough power to go faster with the taller gearing?

 

 

Thank you for all of the suggestions. I'm really intrigued by swapping out just the overdrive pair but for sake of "unnecessary" teardowns will probably just use the 96 tranny as is. I live out in the country and most driving is HWY and so can choose between 3rd and 4th for passing and cruise in 5th. I don't need to be quick from stoplight to stoplight. I would definitely hang on to the 93 tranny though.

 

Good luck with your project, post updates pictures if you can!