First off I do not have all the pictures I would like to add to this post, and I will not bee going over step by step engine swapping. This post is to provide an insight to the issues I encountered while swapping a Series one supercharged 3.8 into my Reatta.

OK let’s talk about the weakest link, the transmission. The two major enemies of transmissions are heat and dirt. I suggest adding two things to help with improving the life of our transmission. Add an aftermarket trany cooler, bigger the better. Second, an add-on trany filter. These are not too hard to find and can be changed just like an oil filter and at the same time. They can be added by removing the steel lines and replacing them with 5/16” rubber trany hose and 5/16” nipple to hose fitting (my favorite are the haden brand).

Start the swap with a complete supercharged engine to include all accessories. This is a must to keep cost down. You will be using all the supercharged accessory mounts and accessories. The only accessory you can reuse is the AC pump. I would suggest using the pump from the supercharged engine, if the engine is 94’ or newer. The reason for this is the pump is designed to run on r134a. This means that the pump is much more efficient while running on the newer refrigerant.

Now I will begin to lay out as much info on modifications as I can recall.
The one and only Reatta accessory mount to be used is the AC pump mount. The reason for this is the front engine mount is bolted to the bracket.
The steel power steering hose must be modified. I did this by cutting the hose just below wear it screws into the power steering pump. Use a tube cutter to cut the tubing. Clean out the burrs and use a piece of 5/16” trany hose and hose clamps to reroute the hose to just under the passenger side of the engine compartment to were the hose originally ran. (this is for the power steering cooler)
While in that area, you must swap in the Reatta’s oil pressure switch. This is a simple screw in and out affair. If you do not do this your IC will read “electrical problem” and the oil pressure will read 255psi (running).
You must remove and not reinstall the little motor strut.
Heater hoses must be modified. This can be done by using four heater hose elbows (found in the Help parts section) or you may use a straight hose connector and Goodyear hose springs (they allow you to bend a hose how you like and not have to worry about collapsing the houses). I prefer the second option.
Throttle linkage and down shift cable bracket from the Reatta must be used (the SC model had an electronic trany so there is no spot for the down shift cable).
The Reatta downshift cable attachment from the throttle body must be used (just one bolt)
The Reatta injector wire harness may and should be used, but it must be extended a couple inches to reach up and over the supercharger.
The Reatta fuel pump must be swapped with one out of a 93’ S-10 Blazer with Vin W (mean Vortec engine) Partsamarica part # P74074

Connecting the fuel rails to the existing fuel lines may be one of the most adventurous parts of this swap. The reason I say this is that I have seen a couple different rail assemblies. The rail assembly I used is from the Park Avenue Ultra. Using this rail I switched to a fuel filter out of a 95’ S-10 Blazer, and found a plastic fuel line out of a gm car that was roughly the length I needed. This mans I did not have to splice the supply line (less likely to fail). I did splice the return line to a from the metal Reatta return line to a plastic line from the Park Avenue Ultra (I figured there is not ass much pressure todeal with for the return path).

I suggest using the Series one engine because many of the components are directly compatible with our systems. If the series two engine will be used you will be looking to modify a lot of wiring, and a few other issues. You would get more power out of the series two, but this also means more likely to blow your trany. Also power is no good if you can not put it to the ground. The series one gave me just what I was looking for, a little kick when passing on the freeway.
Picking your engine: look for a 94/95’. These have a bigger intake and the supercharger was redesigned and epoxy coated. This mean more power and less wear on the supercharged.

If there are any other questions or comments fell free to ask or state.

The ECM has to be reprogrammed for the fuel delivery, but Ryan from Sinisterperformance (gmtuners.com) should have a tune that works well in a couple weeks, once mine is done. I have not checked his prices lately, but he is very qualified and cheap. My setup with the the memcal (chip) adapter and programming was under one-hundred dollars. Also he is very willing to work with you, I started my swap almost a year ago and trip to Iraq and he has worked with me the whole time.

NX, if you don't mind, I'd like to add in my info. Feel free to access any of my photos too if they help.

Mobil 1 ATF would help in keeping the trans cool.

I believe 63viking told me that the throttle cable plate/holder that bolts to the throttle body from like an '87 Electra will bolt on and hold all the cables.

And as per Ryan's suggestion, I used an '89 Turbo Trans Am fuel pump

Thanks for the great write up. Overall not as much modification as I expected. The fuel pump change was one thing I had not anticipated.

There was no mention of any modification to the fuel delivery system other than changing fuel pump and extending the wiring harness. Does the stock ECM and prom programming work with the SC engine?

Philip, The fuel pump is the same, I just figured it would be easier to get it out of a vehicle with less options. The Reatta throttle cable plate works just fine. It just has to be put on the SC engine.


TDman: Thank you for mentioning the fuel delivery system. The ECM has to be reprogrammed for the fuel delivery, but Ryan from Sinisterperformance (gmtuners.com) should have a tune that works well in a couple weeks, once mine is done. I have not checked his prices lately, but he is very qualified and cheap. My setup with the the memcal (chip) adapter and programming was under one-hundred dollars. Also he is very willing to work with you, I started my swap almost a year ago and trip to Iraq and he has worked with me the whole time.

The throttle plat for the stock Reatta wil NOT work on the S/C engine. You need the one from the S/C engine or one from a 89 Electra.
When you are through it should look like this.

Would the transmission from a '91 have a better chance of standing up to the increased power?

the plastic lines will not hold up and will colaspe with vaccume.....and heat.....ken

Philip, I am not sure if we are talking about the same part. I am talking about the bracket holding the power steering resevoir.

By the way your engine bay looked great. I have not spent too much time on making mine show worthy but it will come in time.

One other think I left out, I do not have to worry about emissions so I just blocked off the EGR valve, as did Philip
If you have emissions were you are you will have to make a adapter plate for your Reatta EGR. I guess you could always chance it and hope to pass emissions without an EGR.

I would have thought the CRT would light up with error messages like the 4th of July if you removed or blocked the EGR. Was that not a problem? How about ECM codes?

Yes, A 91 would be better, but it is electronic and is not compatible with our computers. The only course is to have the stock one rebuilt with heavy-duty parts.

Why would you not replace the motor strut??


You must remove and not reinstall the little motor strut.

The upper strut mount can not be used with the SC accessory mounts.

The EGR is removed from the ECM program when tunning is done. Thus no 4th of July on the CRT

I beg to differ with you. I have reinstalled mine and it works fine.

I gotta tell you Jon, you do some immaculate work.

Very nice and very very helpful. Thanks to all who blazed this trail. Assuming one is leaving the trans stock, is it preferable to pull the trans with the original motor, or just leave the tranny and swap the engines?

I try really hard to make everything neat and tidy. Like it was made at the factory. I spent a whole winter engineering the conversion of my Reatta to Supercharged. If I had a dollar for every time I went to the bone yard to look at and for parts, I would not be working part time now. I still have one more project to do under the hood.
My wife says I'm a redneck. "You know you might be a redneck if you work on your car when there's nothing wrong with it"

Did you have to mod it at all? It has been almost a year sense I looked at the strut mount. If it is not too much trouble I would put it back on.

No Modification was necessary. The clearance between the Damper and the strut is close, but it does clear.
And I believe it is there to do a job. To stop some of the torque of the engine pulling up.

Do you actually think that GM would waste as much money building and installing that dampener on the front of the engine if there wasn't a need for It.? I find it very hard to believe that they would. But a lot of people have removed them. Of course a lot have since had problems with their Transmissions afterwards. DUH, tell you anything?

Many 3.8 engines have been factory installed with out the strut, but I do agree with you that there must be a reason for it being there. Also I plan on putting mine back on.

Yes you are correct. Many 3.8 engines were built without the strut, BUT they used a different engine mounting system.

I agree with 63 when he says the use of the strut is probably related to the overall engine mount system. Some identical 3.8s use a much more robust mount at that point than ours, while others have nothing. That said, my guess is that the struts on all but a few or our cars with more than a 100k are useless. By the time I examined the one on my 90 with 187k, it exerted no discernable resistance. Given the orientation of that strut, and the fact that engine torque wants to twist the engine fore and aft, I suspect the little strut is designed to offset stress on the motor imposed by the fact that power is principally to one wheel. I am again assuming the power axle would tend to hunker down a bit with the effect of trying to lift the other side of the motor, which would bring the strut into play. That's just my theory though.

Oh, by the way, could one of you tell me whether you pulled both the tranny and engine when you did the swap, or just the motor? If I keep the old gearbox, I wondering which way is easier.

I pullerd both. there is a trany bolt that is very hard to get to with the engine in. If you have the option of droping the assymbely out the bottom, I would. I did pill mine out the top but it is a very tight fit.

Jon,
I don't know what you do for a part time job, but it should be Reatta conversions. That project looks OUTSTANDING!!! You should consider offering your services. As we can see by reading some of the other posts that there is interest in conversions[myself included].