Help with 93 to 91 engine conversion, and RDH to LHD

[Twofastoocatch]

Hey guys,

So I've had my '91 GTO for a year now, and have come to the conclusion that RDH in North America sucks. A lot. I'd really like to be able to turn left by myself, pass by myself, and not have to call 8+ insurance companies to find one that's willing to insure my car. So I started looking for a parts car about 8 months ago. Well... I found one. So I've got a few questions now and hopefully one of the Guru's here can help.

My Car is a JDM 1991 GTO TT(125000km), My Parts car is a written off, rear ended USDM 1993 3000GT VR4(400000km).

I'm running a '91-93 PnP flash ecu


My plan is to pull the entire wiring harness from both cars, and transplant the LHD harness into the RHD, along with the dash, pedals, column, clutch booster, and center console. (and everything else I've forgotten to list) I've got the engine out of the LHD car, and want to use the O2 housings, exhaust, and the engine harness off that car on the 91.

My questions:

From JDM to USDM, there's the difference in 02 sensors. My car only has one, and the USDM car has 2. I'm assuming I can bolt in the 93 housings onto my 91, if I use the harness from the 93?

The CAS to CAM/CAS sensors. I very much like the look of the newer cars without the huge CAS beside the valve cover, and would like to retrofit this to my 91 setup, as it has very nearly 1/4 of the mileage on it (and a brand new oil pump/60k done less than 3000km ago) Is this do able? Does the 91 block/head setup have the appropriate mounts for the sensors to properly work? Can I TIG them on if they're not there?

Anyone else put a 93 setup into their 91 engine? Any words of advice?

[GTOJOE]

There is a latency issue with the cas conversion that will effect timing. Being a pnp ecu you should be able to resolve that. Check out the cas page on stealth316. As for transferring the wiring harness over I'm not sure it's possible. All the connections are mirrored so even if you flipped it over wires would all need lots of stretching. I would use the usdm harness and just run one O2 sensor. You can customize the ecu ignore the other one.

Sent from my GT-I9300 using Tapatalk

[Twofastoocatch]

I may have not correctly conveyed what I want to do. I am pulling the complete harness from the USDM car, and putting that, along with the dash and pedals etc. into the jdm car. I don't want to "flip" the harness that's already in the JDM car. The JDM harness is going in the garbage. I want a complete OEM USDM harness, in my JDM car to make the USDM car that never existed.

My question is more towards the retro fit of the 91 block to take the 93 harness. I don't want to "mish mash" it. I want something that is OEM, so if I have any issues down the road I can still use a service manual to find and fix things.

So in short, I want to know if I can take the appropriate TDC and CAS sensors from a 93 and put them into my 91, or if I'm better off re building the 400 000km engine, and drop that in as a complete system along with the USDM harness once it's re built.

[green-lantern]

I think if you swaped the heads and timing cog it would be the same. I can't quite remember now.

[Twofastoocatch]

I might just have to pull the engines and put them side by side to figure out exactly what's what. I'd like to avoid using the heads with that high of mileage on them. Thanks guys.

[stealthee]

As Paul suggested the 93 REAR head is different on 91-92 and 93-99. You could use the 91-92 CAS on the 93+ cars with a minor harness modification. Joe pointed out there are latency differences, but on a relatively stock car there should be no issues.

[green-lantern]

I did run a 92 TT ECU in my 95TT conversion for quite a while with no issues but I'm not quite sure how it would work out doing it the other way. I know you want it stock like so I would get the 93 heads rebuilt ((93) wasn't that sort of a hybrid year?) and check the cog alignment to make sure the timing wouldn't be off. You should be good then.

[GTOJOE]

so you are converting a RHD car to LHD? you will have to cut all the holes in the firewall etc. Easier to just buy a USDM shell in good condition and swap everything over to it.

[99 vr4]

I agree, and this frankenstein will be even harder to insure... The VIN will still be a RHD, and when you call your 8 plus insurance companies and try to explain that it is converted, they might not want to touch it or they might want to treat it as a custom...

Not to mention depending on the state, you might need a dmv inspection just as if it was a kit car or a total rebuild... Check with your states dmv head quarters (local offices rarely understand this stuff).

[mjannusch]

On the putting the newer crank/cam sensors on a 2-bolt motor - you can use a rear head from a 4-bolt engine car for the cam sensor mount and the rear cam sprocket from your newer engine, but there aren't any mounts for the crank sensor on the 2-bolt engine oil pump, and there may not be enough clearance to fit the trigger wheel to the crank. You may need to swap in a 4-bolt block to get the crank sensor setup to work, or do some modifications to your oil pump to make it mount and fit.

[Twofastoocatch]

Well, thanks for the help guys, but this project just came to a grinding halt. Or the RHD to LHD part anyways. As previously pointed out, the firewalls are different between the cars. This isn't a huge deal, a plasma cutter makes quick work of that, and as long as you cut out a bigger piece than you actually need, welding it in my car would be awkward, but do able. What's brought this to a stop is the fact that the dash support is RHD/LHD specific as well. And being a structural piece of the car, that directly effects my safety (or the safety of someone else, should I sell the car), I'm not willing to compromise. As for the engine, I have that out, on a stand, and the harness attached to it still, I think I'll build it up, so I can drop it in complete, ready to run, huge horsepower. Thanks for all the advice guys.

[2fnloud]

I would love a RHD 3s :suspect:

Just fiberglass a camera into the left mirror, get a DVD type H/U with A/V inputs, problem solved.

[IPD]

RHD/LHD conversions--i wouldn't even bother. O2 sensors? count your blessings the fewer of them you have (assuming you don't live in kommiefornia or some such).

[Twofastoocatch]

The issue with the O2 sensors is tuning. I only get the rear O2 trims, as there's only one O2 sensor. This means there's only one trim for the whole engine. So if my trim is adding fuel because it sees a general lean condition, and the rear bank is still lean, if I go to take away more fuel for a performance tune, there's a good chance I'm going to break something.