Another cheap rx8...

I was missing some metallic blue rx8 in my life.  

Blown engine.

Thinking gm3900 and t5 wc out of a 2000 camaro v6.

240 hp, 240 tq.  Plus, goes well with a Shanghai spooly boi.

This will be a long term build for daily driver / track / 2 car seats so the entire famn damily can enjoy....

Oh, cool!  I d idnt realize you can see the gm 3500 powered 2nd gen rx7 in the garage!

In reply to wvumtnbkr :

What's it take bellhousing and adapter wise to go from the 3900 to the t5? 

Somebeach (Forum Supporter) said:

In reply to wvumtnbkr :

What's it take bellhousing and adapter wise to go from the 3900 to the t5? 

Nothing.  It bolts together.

Use the 3900 starter and the trans hydraulic throw out bearing.  Use a clutch and flywheel from a 2.2 s10.

Looking forward to this.

Brain dump 3900 information on is please.....

I love everything about this (well, okay, I have mixed feelings about the 60V6 exhaust note, but I love everything else). Excited to follow along.

wvumtnbkr said:

Somebeach (Forum Supporter) said:

In reply to wvumtnbkr :

What's it take bellhousing and adapter wise to go from the 3900 to the t5? 

Nothing.  It bolts together.

 

Use the 3900 starter and the trans hydraulic throw out bearing.  Use a clutch and flywheel from a 2.2 s10.

Interesting. Looking forward to seeing this. 
 

Do you plan on using the donor ecu? 
 
Is there any donor car that is better than another? 

obsolete said:

I love everything about this (well, okay, I have mixed feelings about the 60V6 exhaust note, but I love everything else). Excited to follow along.

The 60 v6 actually sounds pretty good with a decent exhaust.  I'm not saying it's as good as an Alfa romeo, but it doesn't sound like a Beretta with a broken muffler.  Lolz.

Somebeach (Forum Supporter) said:

wvumtnbkr said:

Somebeach (Forum Supporter) said:

In reply to wvumtnbkr :

What's it take bellhousing and adapter wise to go from the 3900 to the t5? 

Nothing.  It bolts together.

 

Use the 3900 starter and the trans hydraulic throw out bearing.  Use a clutch and flywheel from a 2.2 s10.

Interesting. Looking forward to seeing this. 
 

Do you plan on using the donor ecu? 
 
Is there any donor car that is better than another? 

I'm actually not sure yet on which donor.

I am going to contact sinister performance and get his recommendation.

As I understand it, the 3.9 ecu is supported by hptuner and is therefore damn near as good as a standalone.

I am more familiar with the 3500 and 3400 swaps.  I used the stock ecu s for those builds.

I am heading into this imagining that a 3900 is very similar.  (3900 does have dbw, variable intake geometry, and a form of variable valve timing).  Those are all new to me and we can all learn as I go!

Subscribed! This is awesome

Subscribed, I'd like to know how this works..  GRM published an article about swapping these cars recently, https://grassrootsmotorsports.com/forum/grm/video-which-chevy-v6-swapped/180172/page1/.  There are kits out there to help w/the  converstion....but they're not cheap.

Exactly.  I want much cheaper.

I'm willing to sacrifice some perfection for good enough.

Must haves:

Gauges must work

Abs must work (this one is actually a very strong probably...)

More hp and torque than stock

A/c (the plan is for the family to enjoy the car)

Reliable 

No external parts of the drivetrain (car must look stock with hood closed)

Nice to have (but have MAJOR stumbling blocks to make happen)

Traction control

Cruise

I'm trying to do this without cutting up the car too much.  Steering rack MAY need to move a little.  Swaybar may need to move a little.  Hammering on firewall will probably happen.

I get my hoist back tonight and I have a 3400 and trans in my garage.  I plan to see what will interfere in the next few days.  I plan to use this engine as a mockup.  Once I verify that this drivetrain will fit as well as I think it will, I will buy a junkyard 3900.

Very interested in seeing how this one pans out. Lots of cheap RX8's out there waiting for new engines. 

I'm curious why not a 3.6 LFX? Packaging? I guess the DOHC heads are bigger. Maybe electronics?

mblommel said:

Very interested in seeing how this one pans out. Lots of cheap RX8's out there waiting for new engines. 

I'm curious why not a 3.6 LFX? Packaging? I guess the DOHC heads are bigger. Maybe electronics?

The lfx pretty much requires the camaro trans swap.  With the camaro trans swap, the gearing doesn't work with the 4.44 rear end.

In the end, it's a fantastic swap...  it's just 1 issue after another.  In my opinion, it would make more sense to just buy a v6 camaro!

In other words, let's see how cheap I can do this and do it well....

Interested to see how this turns out. Also, I like that color a lot.

wvumtnbkr said:

Exactly.  I want much cheaper.

 

I'm willing to sacrifice some perfection for good enough.

 

Must haves:

Gauges must work

Abs must work (this one is actually a very strong probably...)

More hp and torque than stock

A/c (the plan is for the family to enjoy the car)

Reliable 

No external parts of the drivetrain (car must look stock with hood closed)

 

Nice to have (but have MAJOR stumbling blocks to make happen)

Traction control

Cruise

 

I'm trying to do this without cutting up the car too much.  Steering rack MAY need to move a little.  Swaybar may need to move a little.  Hammering on firewall will probably happen.

 

I get my hoist back tonight and I have a 3400 and trans in my garage.  I plan to see what will interfere in the next few days.  I plan to use this engine as a mockup.  Once I verify that this drivetrain will fit as well as I think it will, I will buy a junkyard 3900.

 

I love it.   A V6 RX8 would be perfect in my opinion.  W/the clamshell doors the back seats are somewhat usable.  The main limitation w/the Renesis engine (aside from early reliability issues) is the abysmal fuel mileage.  The V6 should provide adequate power and mid-20s MPG (maybe even 30)...and it's not a Camaro or a Mustang. 

Eh, this one isn't gonna give good mpg.

The final drive ratio says I'm gonna be spinning about 3100 rpm at 80 mph.

Car seats fit in the back of an rx8.  It even has the latch system!

I am still concerned it won't fit without major mods, but we will all find out together.

If it takes as much work to fit as an ls1, than this is a stupid project.  However, I'll follow through bevause then I will have a playform to do stupid stuff (like see how much boost a 3900 can take stock, or NAWZ!).

Edit to say....  this thread has already had more interaction than my rx7 build thread were I put a 3500 and t5 in that.  Weird.

wvumtnbkr said:

mblommel said:

Very interested in seeing how this one pans out. Lots of cheap RX8's out there waiting for new engines. 

I'm curious why not a 3.6 LFX? Packaging? I guess the DOHC heads are bigger. Maybe electronics?

The lfx pretty much requires the camaro trans swap.  With the camaro trans swap, the gearing doesn't work with the 4.44 rear end.

 

In the end, it's a fantastic swap...  it's just 1 issue after another.  In my opinion, it would make more sense to just buy a v6 camaro!

 

In other words, let's see how cheap I can do this and do it well....

Ahh, makes sense. Yeah, from what I've seen it seems like a complete changeover of all Mazda driveline to Chevy. I wonder, does anything besides a rotary bolt to the RX8 transmission?

I'm interested to see how cheap you can make the swap. 

From what I can find, there are adapter plates for the 1uz, Honda K, jz engines, etc.

The issue is that the stock gearing means crazy rpms at normal cruising without spending several $k on a rearend swap.  

I know there is a British company that makes a bunch of adaptor plates for the RX8 transmission. They have a Facebook page that you can look for.

Out of all the choices they have, the AJ-V6 / Duratec / MZI V6 engine. They are light, compact and can rev. Heck, I feel that's the engine that should have been ther in the first place

fanfoy said:

I know there is a British company that makes a bunch of adaptor plates for the RX8 transmission. They have a Facebook page that you can look for.

Out of all the choices they have, the AJ-V6 / Duratec / MZI V6 engine. They are light, compact and can rev. Heck, I feel that's the engine that should have been ther in the first place

This is true.  However, you would still be turning 4k going down the interstate at 80mph.  

That's a bit too high for me.

I believe PMC is the company you are referring to.

You would need to swap the trans or the rear end.  Both lead to increased cost and scope.  The trans I picked has a .72 5th gear ratio which drops about 1k rpms at highway speed.

Since the 60degv6 bolts to that trans with known, easy to get parts, it starts to make more sense.

3,100 rps at 80mph doesn't really sound that bad to me for a MT car.  I'm pretty sure my old MKIV VR6 GTI spun over 3K at 75mph.  My newer turbo golf Alltrack is somewhere around 2500 rpms at 80mph, which is nice.  

Hoondavan said:

3,100 rps at 80mph doesn't really sound that bad to me for a MT car.  I'm pretty sure my old MKIV VR6 GTI spun over 3K at 75mph.  My newer turbo golf Alltrack is somewhere around 2500 rpms at 80mph, which is nice.  

Exactly.   That's the trans I chose.

The stock trans would be 4k rpms at 80mph.  That's just a bit too high.

After some more careful measurement, I probably need to move the steering rack down a bit (Collins make brackets for like $160).  The swaybar will probably need moved too.  This is fairly straight forward and I will document that part.

Now, to disconnect those items, put the engine in for first fit and see what hits...

Hopefully, nothing else needs modded....  my biggest concern is where the shifter sits.  I will do major firewall surgery if it means I leave the stock interior where it is to get the shifter to line up...  we shall see...

So, how small is this engine?

About 17 inches wide, 18 inches long, 26 inches tall.

That is without accessories or exhaust manifolds.

5 gallon bucket for reference.