GM 3800 V6 Swap
 

The car:


2004 RX-8 6 speed
94,000 miles, second blown motor. Rusted to bits body.
Total gut in progress.

The engine:


Came from a 1998 Pontiac Grand Prix GTP (So I was told)

Clean engine, well taken care of, Already had a smaller pulley.
Decided to put new Main and Rod bearings for piece of mind.


Also got a new timing chain on it and a complete gasket set with aluminum carriers to thwart the common leaks these engines have.


Got around to a test fit.


Yes, it's a heavy engine, It's also a gutted car and considering the shifter location I think the engine sits pretty far back still.


As far as mods to fit, I think some modding to the supercharger is in order to nestle it up against the firewall and turn the throttle body to the side so It can actually fit and work.

Then I'd probably need to space the sway bar forward a couple inches and drop the steering rack, which will happen with a hydraulic rack I'm fairly certain.

Then there's plenty of space around the engine for exhaust or turbos should I decide to switch over.

I have a manual flywheels that fits, It'll bolt to a Doge Dakota Bell housing that'll make it fit to my Pontiac Solstice Transmission.
So far it's looking VERY promising.

No more VR6 swap? Did you verify it is an L67? Even if so, pretty lame in stock form. Much like the VR6.

You have a pontiac solstice transmission? Did it have an ecotec with it?

Here's a good site for 3800 GM performance parts. 3800

I don't think I would have gone GM, but why not go with the ecotec motor the transmission was connected to from the solstice?

ZZP has a lot of good stuff for the ecotecs as well. ecotec

Once I was able to get a good look at fitting the VR6 I realized the cost of such a project would really make it take forever to get finished. Too much custom fab and machining cost for me.

It is in fact an L67, beefy rods (compared to the NA counterpart)
It's listed at 240hp and 280 ft-lbs stock, but the forums claim that's a conservative rating.

I do have the trans, came from an '08 Solstice. I didn't get the engine, but I have the same engine in my G6, neat little engine but the 3800 has more room for power.

I ordered from ZZP for the G6 as well as the gasket set and t-stat for the 3800.
The 3800 will bolt right up using a Dodge Dakota bell housing, and I didn't really want to go with another 4 cylinder.
I was thinking I'd keep it supercharged until everything gets finished, then invest in turbos for more fun potential.


These engines can push 500-600hp on stock internals fairly easily.
With the smaller pulley, larger injectors, meth injection and a tune I'm being told 400 ft-lbs of torque isn't hard to accomplish.
So we'll see

How did I know he'd be the first one here to try and shit on your swap.

Looking good! Great engine! Can't wait to meet up with youon race day. :)

Don't hold your breath. I'm not that either of your swaps will ever be completed. But it's nice to know you are thinking of me.

Looks like it fits nicely. I'm jealous of all that space.

GLWB

Thanks! I'm sure with the accessories and supercharger in place it'll take up a bit more space.... just a bit.
The haters just fuel the need to finish :yumyum:

Right 9k. Cause we both spend 1000s of dollars and 100s of hours of research for no reason.

Prescription8 - At least you have ready-to-boost engine management. :) I'm still trying to decide between pggy-back or go stand-alone and attempt to get it exempted. There's something about the challange of maintaining total drivability and compliance that I seem to enjoy. Some of the guys here don't get that it's the journey not the destination that fabricators enjoy. They just assume buy a bolt-in kit and be done with it but that's the same as just buying a car and being done with it.

It is quite a journey I'll admit that haha.
But yea it seems the 3800's ECU has quite a lot of room for tuning and variables.
I did some research on ems/magasquirts and a lot of people just recommend using the stock ECU.
I understand there's some limitations as to how high the tables go regarding MAF Freq, but alas there are ways around that as well.

As much as I'd like to run a stand alone with pretty minimal wiring. I think tackling the stock harness and getting the stock ECU tuned will be my best and most cost effective option.
Plenty of wires to dig through!

Just use a larger maf and adjust accordingly. Done.

Yup. The common solution is one of gm's v8 engine's maf and tb (lq4)

After some weighing of options and some other parts popping up I'm leaning towards going turbo from the beginning. This way I can avoid having to modify the super charger, and I'll get more potential for fun.

Im surprised it fit behind the battery brace. Its gonna gain some real nose weight that iron motor and turbo system. Im just curious why you didnt use an LS1. Approximately the same weight, tried and true platform, swap options already available and not too far from that 6 cyl dimensionally speaking. Plus they make more power easier and more reliably. Im not bashing your build but I believe the obvious choice over the 3.8 would easily be the LS motor.

LS Swaps are just too common IMO. Every drift day I attend there's at least 3 or 4 LS swapped cars there. I want to be different and do something that hasn't been done. I enjoy the challenge of making it all fit and work as well as having something unique.
Can't buy a swap kit for a 3800 after all lol

https://cimg1.ibsrv.net/gimg/www.rx8...022b6106cc.jpg

Theres a reason they are popular. Its cool to be different but......its also cool to have a car that works well.

Just because it isn't an LS motor doesn't mean it won't work well...

So I weighed the long block today out of curiosity.
294.4 lbs

Guess we will never know. Only LS swaps and a windsor swap have ever been able to test how well they work. The 3.8 can be a badass motor. Takes alot more money to make it do the same things the LS will. 295 lbs isnt light for a stripped down longblock.

It may not be light but I think it'll work out well regardless. I'm pretty sure with the full gut and some relocation of items I can probably balance it pretty well. Hopefully lol

I see a lot of V8 and 4cyl turbo swaps. I think it's about time V6 swaps start to fill in the mix

Plenty of V6 swaps have started...

Yep. 3.8 is a decent motor but takes a lot of money/work to make into a formidable power plant. Splayed mains, pricey heads, and parts market is small/expensive. LS motors work well because you can make a lot of power with "junkyard" parts. Guys routinely make 450+ hp with a rectangle port top end 6.0 and a large cam. Your 3.8 will take much more money and innovation to get to that number. You seem to know Kicker well and he is quite innovative. Good guy to know. Judging from your previous build and the pace of his, it's not likely we will see any results soon though. Don't mind the rotary guys trolling this thread. They love to see swaps fail. I'm excited to see a RecipX8. I would have chosen a better motor though. I daily'd a GTP for a while. Fun but nothing to be proud of with the amount of money I had in it.

I don't mind piston swaps, I can appreciate a clean build done properly. The problem is that 99% of the pistion engine swaps result in failure or even when they do run the car overall is still a jalopy. But there are a couple (exactly two) that I can appreciate. As for this one, well it will never happen, mark my words.

Not true. There are many swaps I read about and don't comment on.
I don't claim to know more than anyone, but when people who know more than I do offer advice, I usually consider it a good idea to listen.
If someone chooses to ignore conventional wisdom that is proven, and choose to waste time and money, go right ahead.
They'll get no attaboys from me, and deserve any scadenfreude they endure.

It's unfortunate my RX-8's body is so rusted. I can post better pics but it's pretty tragic. That's the main reason I'm just going for the full gut swap.

I've seen other v6 swap threads, but at the track I see very few V6 swapped drift cars.

Have you wondered why?
Have you thought about cutting your losses and going with a 13B or other swap that would make more sense or be easier?
At least one that has a successful history with some kind of support system?

There's plenty of support for the 3800.
Also I'm a big fan of torque.

Do tell. :jump:

I was referring to support as in kits that are specific to RX8s swaps.

Obviously, there are too few mechanical geniuses building them
Shouldn't you be doing some research, or rummaging through junk yards?

Kits take all the fun out of making a swap work yourself IMO

I used a kit and built one hell of a car. I wouldn't take what the rotary guys say very seriously. They don't bring much to the table when it comes to this kind of stuff. they just roll this side to ball bust. I hope this comes through but judging from the "gutted" comment and motor choice I will assume it's gonna be a long time if it happens. Keep pushing though OP. I'm watching and excited to see another swap come through

Heh, I don't take anything the rotary guys say seriously.
Most of the car is already gutted, Just need to work on the wiring and sound deading, dash and hvac removal.
Engine needs a little more work, a lot of parts are still needed.
I'm anxious but I don't see this getting done this year.

I'm hoping sometime next year to see it finished, mid summer would be great.
Unless I decide to work more jobs and really push the funding for this project it won't progress any faster

That's a 2 headed coin, because most of us 'rotary guys' don't take the junk yard piston swap guys seriously.
Unless you want to build a junker for the track, that is.
Then it's more of us being sad that you took a car that was designed for a rotary engine and ruined it.
But, the flip side is, maybe one day our unmolested 8s will be worth more because there will be fewer of them.

moved LSXREX's posts and everyone elses's discussion about his posts to the lounge thread for the forum.

Yea, as I mentioned before. the rx-8 I got is just rusted up pretty badly. IMO it isn't deserving of a clean build with functioning factory electronics.
Hopefully I can balance the weight fairly well and retain some handling.

Sorry we got derailed by the LS guy.
Are you planning on using it as a daily driver?

Heh,
I was reading it but didn't get a chance to reply in time. Oh well

Nah.
I'll probably drive it to work or show it off every so often, but it'll likely get stored through the winter.
My main goal is track day/drift day car. I just want to have fun with it.

Here's some rust spot shots...


Basically there are no more rocker panels. and the rear quarters aren't too far behind...

That's pretty bad.
My old 4WD is rusting out worse than that, but it's a '95.
If you get your swap finished, maybe you can try your hand at bodywork.

Holy crap.

Yea I was thinking about it. Most likely just cut it out and find something from the hardware store to fix it, or at least make it look better.
I was thinking of playing with the look, making it go kind of rat-rod and letting the rust do it's thing.
Or I can cut out as much rust as I can, put some fender flares and see what happens.

Really that's all for last anyways. So it all depends on how long I take and how much of that rust grows heh

Buy 200's leftovers and combine!

i can cut panels off my my car

Heh, I'm not too worried about it. But I'll keep it in mind should I decide the car suddenly becomes worth it

Once your up and running you can easily swap your drivetrain into another chassis. It's unfortunate to say (because I really like the RX8) that these are sort of disposable cars with plenty of rolling chassis for years to come.

Oh by the way. I've started on the driveshaft jig. You'll have to do some measuring and see if your driveshaft length is close to mine. Being the same transmission it'll probably be damn close.

And just say no to the double flywheel!!! :lol:

A dual mass could actually help me, but nah I'm fine with my flywheel..... for now heh



Bit of an update. With the Kicker's help I got my driveshaft situated.
Same thing here, Rodeo Driveshaft with an RX-7 rear flange and Rodeo trans flange.
Damn near perfect length, and now I don't have to pay to have one changed or balanced.

Finally got to the junkyard and picked up some manifolds off a V6 Camaro.
Also scored some extra sensors and coils.

I don't have much knowledge on GM power trains but would an LFX swap work well in this case?

AFAIK they're a lighter option than the LS, they're abundant, and I've only seen the swap attempted once for an 8. Thoughts?

Those rust photos made me cringe like hell too.