I have a new website where I’ll be managing my 4G63 swap notes for the 3000GT/Stealth. This website will no longer be updated for the notes and they’ll soon be removed as I plan to repurpose this website to be for my car projects and racing stuff in general.
The new website is http://3S4G.com and contains all of the swap notes on this website, but in a better format and all in once place instead of having to jump from page to page to get information like you have to do here currently. It is just a much better format.
As I’ve mentioned, I’ve been doing a 4G swap on a 95 3000GT Spyder SL. This was a whole different kind of experience from my VR4 swap for many reasons, most of which were due to this starting life as a FWD NA model, some because we are keeping all the features like AC, Heat, power steering, etc.
Some pretty critical things came up during this build, one of which was learning that 92+ DSM FWD transmission had 27 spline drive shafts and the driver’s axle on the FWD models were a single long drive shaft verses the AWD models having an intermediate shaft. I didn’t have any issues like this on my AWD swap and didn’t have any idea this would come up. My recommendation is to NOT use a FWD transmission at all for this swap. Use an AWD transmission and have the center diff welded to run it as FWD so that you can use the AWD intermediate shaft. I’m in to this build too deep and changing out the transmission was not an option for me. Jacob Grubb made some custom brackets and used a 3000GT intermediate shaft on his car which is currently down for some maintenance and he was kind enough to sell it to me so that I could get this thing done. I still very much recommend against the FWD transmissions because these custom brackets aren’t produced by anyone and would need custom made if anyone did the swap like this.
The next issue I ran into is that the FWD models had a 2.5in exhaust where the AWD models had 3in exhaust. I didn’t notice this on my VR4 because the downpipe would bolt right up to the exhaust. That wasn’t too critical because I already had a new exhaust for my Stealth TT that needed to go on, so I put it on and put stock TT exhaust on the Spyder. That just kinda worked out.
AC lines proved to be more of an issue than I thought they would. Originally it was looking like 2G DSM AC lines would work, but they didn’t. The 2G AC Compressor was the right one to use, but AC lines need to either be custom made or stock 3S lines would need cut up and modified.
I also learned that the stock NA fuel pump is too weak even if I wanted to run a smaller turbo setup. The recommendation from my tuner is at least a Walbro 255 with a hotwire kit.
The last fun bit was just due to it being a Spyder and because we manual swapped it from being auto. There was a yellow/black cable taped up under the center console that needed wired to the ebrake to make the top work with the manual swap. It was an easy fix, but it took a lot of research looking at wiring diagrams and the help of a few different people in the community. Shout out to James Grieve at 3SHub.com for his assistance helping me understand the Spyder wiring diagrams.
The car is almost done at this point, it runs great but due to the intermediate shaft issue, it isn’t driving yet. The intermediate shaft is on the way and then we will be ready to drive it finally!
One big one that no one has documented yet is how to keep your Air Conditioning! AC is one of those creature comforts that is often deleted in cars that are just meant to go fast because it is heavy and inconvenient to work around sometimes. For those of you who want to do this swap and maybe even daily drive it, AC is a MUST in the summer in my opinion.
On to the important details. You can do this on either a 6 bolt or a 7 bolt 4G63 engine. Here is what you’re going to need:
All of your stock 3000GT AC stuff (compressor, evaporator, receiver, condenser, etc.)
2G DSM (95-99 Eclipse/Talon 4G63 models) AC Compressor, bracket, and tensioner. It is VERY IMPORTANT that you get these parts from a 2G DSM that has a 4G63! 420a parts DO NOT FIT THE 4G63.
Two AC air compression fitting kits
I do plan to offer making an adapter harness for people that want to keep their AC but not want to do custom wiring, so don’t worry. The grunt work is done though, figuring out the right combination of things that works was the painful part since I had to buy several AC compressors and several sets of AC lines from different cars to figure out what combination worked. My initial thoughts about what AC lines might work were wrong, none from any car I’ve found is a bolt up and go solution. Both AC lines will need to be modified to fit. I recommend the Doorman AC line splice kits. I didn’t measure what worked or where I made my cuts to tell anyone the exact measurements, but you can fairly easily figure it out with it in the car.
For the wiring, I will make this as simple as I possibly can. On the 2G DSM compressor, there is a triangle connector that has 3 black wires. Two are for the sensor on the compressor, 1 is for the clutch. See the picture below for the 2G Compressor.
The 3000GT/Stealth AC compressor on the other hand has all of that and one more sensor that just has 2 white wires. I’m told that is an RPM sensor to shut off the compressor in the event of the belt breaking or something like that. That is some sophistication that the 2G DSM just didn’t have.
So what I did initially is not how I would do it again, and the only reason I say that is because it would have been easy to make an adapter harness instead of cutting the end off at the compressor and putting the other end on. But that is what I did for my initial test and here is how:
On your 2G DSM AC compressor, cut the triangle connector off.
Look at your 3000GT/Stealth compressor connector, remember which wire went to the AC Clutch (maybe label it to save yourself the headache.) Once you know which is which, cut the connector off and get ready to put the connector from the 3000GT/Stealth compressor on.
When putting the 3000GT/Stealth connector on the 2G DSM AC Compressor, make sure you connect the AC clutch wire to the AC clutch wire on the DSM AC Compressor.
The two black wires from the sensor on the 2G DSM AC Compressor will connect to the two other black wires on the 3000GT/Stealth AC Compressor connector. It does not matter which is which.
The two white wires are for an RPM sensor which the 2G DSM compressor does not have, when you cut those, they’ll need soldered/connected together. The sensor would typically shut off the compressor if it is running and isn’t spinning to prevent damaging it, that is in the event of a belt breaking. That is just some sophistication that the 3000GT/Stealth had that a 2G DSM did not.
Done! Now you’re ready to put it on the car and plug it in.
The big down side to “method one” above is that you need to do that again if you ever have to replace the AC compressor for any reason. That is why I decided to have a method two, which is a simple adapter harness that you can make on your bench easily if you have the spare connectors. On that note, I highly recommend buying some hacked up wiring harness to keep around. They’re infinitely useful for making adapter harnesses.
For Method Two (making an adapter harness), you’ll need the following:
A female triangle connector with pigtail that plugs into the 2G DSM AC compressor. If you can get one from a 2G DSM wiring harness, that is great! Otherwise, this connector exists in several places and you can hack it off a spare 3S harness.
A male rectangle connector with pigtail that plugs in to 3S harness for the 3S AC compressor. I just cut this off the 3S AC compressor personally.
2 foot of 16GA wire. I like to give myself some play room when making things like an adapter harness, and since I have a spare harness to hack off of, I have plenty of wire.
Once you have the two connector you need, you just need to match up your wires. Best thing to do here is to plug in your triangle female plug with its pigtail right into your 2G DSM AC compressor so you’ll have a pretty straight line view of which wire is which. I cut the rectangle connector off the 3S AC compressor after labeling which wires were which, now you essentially want to wire them together to where they’ll be wire to wire all the same. On the 3000GT/Stealth AC compressor connection side, we won’t have where for those two white wires to go, so we want to write those two together inside of our adapter harness.
I highly recommend making an adapter harness over method one if you have the connectors or can source them. It will save you from having to redo all of the wiring changes if you ever have to replace your AC compressor.
I’m going to build several of these adapter harnesses and sell them for $50 shipped if anyone is interested.
The slice and splice method. Basically following all of the same information as method 2, except you just cut the rectangle male connector off of your 3S harness and put the 2G DSM triangle connector in its place while looping the two connections that go to the white wires on the 3S compressor connector. I’m not a big fan of cutting a good wiring harness up, so this isn’t my preferred method, but it will do the trick.
There it is folks! Now you can do your 4G swap and keep your AC without having to buy a bunch of unnecessary parts or do a bunch of research to figure it all out.
Most of you probably know by now, but I realized the drag racing lifestyle is not for me. While drag racing is a lot of fun, it is very expensive. It took me 3 years almost to build this car due to lack of money, then last year at The Shootout I watched a lot of people blow up engines and transmissions that cost more than mine lol.. To be clear, that is not a failure on the 4G platform at all, it is just a thing that happens when you try to push 1000hp+ on a 4cyl lol.
I’m too competitive for my wallet size to be doing drag racing, so I’ve gone back to Autocross where I came from. Autocross is what I’ve done since I was a kid (literally started out in go-carts at 8 years old…) Unfortunately, the VR4 is too fat for that sort of thing and I too was too far for a 10 point cage in a car I just wanted to be able to drive.
Long and short is that I took the build too far and ruined it for myself. The car has been parted out and sold. I’ve moved on to a 1990 Eclipse GSX that I bought to replace it which will be fun for things like autocross and street driving since it isn’t completely gutted. It needs a bit of work still but I have my 90 Talon still to take parts from to swap over to it since it is a cleaner car.
That is not the end though! I still have full confidence in the 4G swap and I’m about to finish one up for a friend. I’m doing the first ever 4G63 swap into a 3000GT Spyder SL currently. His car started life as a non-turbo 6G72 with an automatic transmission. He wanted a fun ~400hp setup where he could keep the creature comforts of heat, AC, power steering, etc. We worked together on a budget and got a list of parts needed together and he shipped his car to me from Florida to Ohio so that I could do the swap for him. So far, the build details are pretty simple. We’re doing a 6 bolt 4G63, 20G turbo, ECMLink V3, 560cc Evo injectors, Quaife LSD with a DSM 5 speed transmission. The idea is a pretty straight forward build that should last. I’m currently waiting on the remainder of parts it needs to be completed, so we’re hoping to make some noise soon!
Below is a sneak peak! Excuse the messy garage, yours will be too if you do this!
I learned a lot of important lessons from my swap on my VR4 and I’m so glad I documented them as well as I did on this site. That said, the site will remain up and will be used to document any future swaps I do and add any new lessons learned to my 4G swap notes. I have some really great info that I’ll be adding to that soon as well!
As of now, the car is parked for winter. I never ended up posting back after the 2019 Shootout which was entirely because I was just exhausted.
The VR4 made it around the autocross track 5 times Saturday, the turbo is just too laggy without nitrous to even start getting in to boost on such a tiny autocross track. At the end of my 5th run, I went to go back in line and a guy told me I was leaking something. I checked and found the water pipe O ring broke. I asked around a lot to see if anyone at the track had one I could buy and couldn’t find one, then I called around to local parts stores and the earliest any could get it was the next day. So a really dumb problem ended my weekend. Needless to say, I’ll always have a few of those on hand going forward lol..
The car idled well, but never boosted. AFRs all over the place, tune was just a disaster. I couldn’t get ahold of the guy who tuned it the whole day I was trying, so taking it down the drag strip wouldn’t have been a good idea anyway. I also didn’t have nitrous installed yet and it seems my converter choice (IPT Restall) was a bad choice without nitrous. Not much else to say about the shootout except that I still had a great time hanging out with fellow 3S and DSM guys and watching some good racing.
Because I never liked having to rely on anyone for doing anything to my cars, I’m doing the HP Academy tuning classes and I’m going to learn how to do it myself. It makes the most sense for me to be able to understand how to make changes at the track anyway, so that is just how it is going to be.
So anyway, winter build plans!
I’m planning on a bunch more weight reduction, still a lot of weight on the car that could be lost. God knows I’m not losing any from my gut, so I’ll get to drilling spot welds lol.
I have my fiberglass doors that I intend to put Lexan windows on, then painting them and the rest of the car.
Installing Nitrous Express kit.
Possibly replacing torque converter with one that better suits my build. I should have researched converters a lot more before I bought the IPT Restall that is in the car.
Setting up some custom made paddle shifters to use with my Forced Four shift box.
Having one piece 99 headlights/corner lights made from Carbon Fiber and ducting a hole in them to my turbo and oil/trans coolers.
Cleaning up wiring or making an entire custom wiring harness, I haven’t really decided yet. It is pretty far at the bottom of my list for winter because everything currently works.
Test and tune once the weather gets better.
Exciting stuff coming next year for the VR4. Now that it runs and drives, I can focus most of my efforts towards weight loss. I don’t have any intention of making any big mechanical changes like turbo or anything like that, but that could change if an FP Zero comes up at a reasonable price haha. Unlikely though, my setup as a whole mechanically should meet my goals at the track early next year. If I have a thirst for more between March and the Shootout, maybe I’ll change it up, but I doubt it.
After all of this time, the car is finally ready! It starts, runs, and drives! It needs a wheel alignment which it’ll be getting on Tuesday, but it is good to go finally.
I ran in to some issues last week when we were trying to wrap things up and found that the intermediate shaft I was trying to use from my 5 speed setup was not the same for my auto setup. I ordered the correct intermediate shaft (2GA Auto DSM intermediate shaft) and put that on today which resolved that problem.
I was only planning to Test and Tune this year at The Shootout, but decided to register for Max Effort to help try to keep it alive. My car is definitely not set up for autocross, but my hope is just to keep that event going because my Talon will be set up for Max Effort for next year.
Anyway, I’m exhausted and still have a lot of cleaning up to do in my garage lol. Ignore all of the fluid spills, already fixed that problem. I just haven’t cleaned up the mess.
Lots of progress to report. I haven’t been updating as frequently as I’d like but I’ve been super busy trying to get the car ready and all of my other adult responsibilities.
So over the past few weeks since my last update, the following has been done:
Built auto transmission and tcase installed.
6 speed rear diff installed.
FP2 cams installed.
Roll cage installed.
The part with the cage being installed happened over this past weekend and my welder ran out of gas unfortunately. All of the pipes are in the car, half are tack welded and the other half are fully welded in. I’m getting my tank refilled this week and the cage will get the rest of the welds done this weekend.
Currently as it sits, I need to install the forced four shift box, nitrous, side exit exhaust, front axles, fluids all around, and wheels. This should all be able to happen this week then the car is off to the shop for a wheel alignment before some test drives! We’re 19 days to The Shootout and grinding hard to get it done as I can.
I’m finally picking up my built auto transmission on Sunday! My kiggly flex plate arrived yesterday, I already have my IPT converter and forced four shift box with TCU built in. I’m currently still waiting on my depowered steering rack which is my big hold up right now.
I pulled out the 5 speed transmission a couple days ago and over the next couple of days I’ll be installing the auto shifter, shift box, NA knuckles and calipers, and front Addco swaybar. I’ll also be pulling the steering rack so that I can put the new one in as soon as it arrives. I’m making some pretty good progress. Once the car is back together next weekend, I’m driving it to the shop to get my roll cage installed after a little bit of tuning.
I’m also looking for some good tires to drag race with. I bought some nice RX7 wheels that I intend to put drag tires on very soon. Once I have those, I’m going to see when the next time I can get to the track for a test and tune will be so I can see what it can do finally!
Anyway! I’ll update more over the next couple of weeks because we’re getting back in to crunch time for the Shootout!
I’ve received some of my parts so far but haven’t had a chance to install some yet.
The roll cage, side exit exhaust, and nitrous kit have arrived. I am hoping to get all of those in the car in the next couple of weeks. My built auto will arrive on June 15th and I plan to have that installed pretty soon after. I may go ahead and pull out the 5 speed stuff and start getting the car ready for the auto stuff before then.
I did change my intake manifold from the Magnus one to the JMF one. Both probably perform the same but I originally wanted the JMF one when I was getting this build together on paper, and now I have it.
I’m still waiting on the depowered steering rack which should be here in the next week hopefully.
The car is down on all 4 wheels currently and the coilovers are on. It can be driven currently but needs more tuning before I start trying to play with wide open throttle.
Also! I’ll have an actual weight of the car here pretty soon because Larry Koren let me borrow his awesome scales. I’m going to sit the cage in the car just to make sure that weight is accounted for until I can get welded in, but I’m very curious as to what the weight will be. My guess is around 2900lbs currently.
I finally got around to starting the car on April 15th for the first time since swapping in the 4G63. It had some issues where the CAS needed adjusted and it seemed like injectors 2 and 4 were stuck or something. I unplugged and plugged back in the rear injector harness and both connectors to the injectors and got it running on all 4. The car sounds pretty solid so far. I drove it in to the garage at my new house which was the first time it has moved under its own power in over 2 years, good feeling.
Now for the fun part! I decided I want this car to be fast, so I’ve decided to drop the idea of staying 5 speed and I’ve ordered an IPT built auto transmission, IPT restall converter, and forced four shift box. I also have a few other things on the way! I ordered a depowered steering rack, 10 point roll cage, side exit exhaust, and a Nitrous Express kit. I’ll probably take it to the track to see what it can do with the 5 speed for a couple of runs before I do the swap just so I’ll have a bit of reference on how much faster it is.
I replaced the front struts with coilovers so far, and I am going to be doing the rears this weekend. I have Addco front and rear sway bars that are going in soon also.
I’m trying to get a good quote on some CF doors and fenders to help lighten up and I’m in the process of deleting almost all of the interior except my Corbeau driver seat. Planning on getting it over to a scale at some point soon!
In addition to all of that, I purchased a house on April 1st of this year. Thankfully, I have an over sized 2 car garage to work with now instead of my old one car apartment garage where I built most of this car. Much easier to make progress when I have room to work!