KFC

There are a lot of good RX8's out there with dead engines and they seem to go for about 4 to 500 quid. I like the idea of the V6 in a RX8, lovely sound and power, I'm not after ridicules power, 200bhp-230bhp mark. Cars with the engine I think I want go for about the same money, an engine out of a mondeo or S-type. I'm driving a MX6 with the 2.5L klde engine but I thought a AJ30 out of a s-type would be better for the engine lay out with a lot of usable parts, manifolds, mounts, bolt on the RX8 gearbox? Adapter plate needed? I'm not sure but I thought the rwd version with the duratec based engine would be ideal. I would like to try and use the stock inlet and ecu just to keep the cost down for now. I'd just like to get one going sooner than later so I can get rid of the MX6, What do you think?

KFC

Well, I've made the decision, I bought a KLDE V6 so I can take my time to rebuild. If not then I just spend money to get it through but I don't want to. The mechanical side is easy but the electrical..... It will be a learning experience for sure. The 5 speed box for the 8 will be better, engine speeds with LSD.
It's such a compact little engine, dimensionally the V6 are near identical to the rotary complete! The V6 is 1 inch longer, same width. And 2 inches shorter, I can't believe that Mazda never put their own V6 into the RX8???

KFC

In terms of moving auxiliaries and cutting, I don't think it's a lot compared to what other people have done.
I'm still surprised that my original calculations for engine choice were right, just look how close the crankshaft pulley and sump lip is to the steering rack and subframe!! Ok, I do have to mod the sump but I thought I might have to cut the front of the block but I don't. Moving the brake lines and abs unit will be fun, actually like routing and manurfacturing pipes so it will look good. I can keep the clutch slave where it is, just bleed it before the engine goes in, the bleed screw sits about 7mm behind the LH cylinder head so access is tight.
By the end of the month I hope to have the mock V6 in with engine mounts in progress. I'm able to use 2 RH RX8 engine mounts with an adapter plate to the block, again, this has been mocked up :-)

KFC

My mock up V6 is in my 8 and I only cut 2 small sections out of the bulkhead, put the 5 speed gearbox in a 231bhp version, stock flywheel, clutch, gerabox back to the wheels are standard. Stock subframe and steering rack, moved the ABS unit and hard lines, should have about 210bhp 170lbs of torque. Not balistic but still fun to drive. In England we have a lot of corners which is where the fun is, not in a straight line, boring. I started the mock up chassis that I scrapped in May then started my real one August, hope to have it done before Christmas..

RIWWP

iTrader: (2)

Wait, so you want another engine that has less power than the engine that doesn't require any extra work to replace? I am honestly trying to figure out your reasoning for doing all the work to put in a slower engine, rather than just getting another Renesis...


The RX-8's ECU will not be able to run a V6. Different injector behavior, different spark count, different spark sequence, etc... You will need to use another ECU, which will mean that all the existing RX-8 electronics will need to be removed or completely re-written with custom firmware.

Have you measured the difference in where the output shaft ends up being placed? The Renesis exits from the center, a V6 exits from the bottom. Same dimensions of the total block means you have a much lower transmission mounting location, or the entire engine has to sit higher, potentially creating different problems.

They did, it's called a Mazda6. "RX" means Rotary Experimental, so anything else in the chassis is called something else other than "RX".


Physically fitting the engine in a location is perhaps the easiest problem to solve in any engine swap. For the RX-8, the significant additional problems will show up with the electronics, which is seperate from the wiring problem.

I get the appeal of engine swaps, though I struggle with your choice. Your goals are met by the engine that will take you less than a day to install, but you are instead choosing to install an engine that will require significant amounts of work and you will never recoup the costs of.

Legot

iTrader: (1)

¿Por qué

Like RWWIP said, you're basically replacing the rotary with another engine that's essentially identical (or worse) in terms of power alone.

Is it for reliability, because I don't think that comes from engine swaps.

At the end of this, I see you coming out with a great handling car that's low on torque with only modest power, coupled with intermittent unreliability. I.E. a Mazda RX8

KFC

I knew this might upset a few people but this is different. I love driving the car, I hate the engine, no torque and you have to rev the **** off it to get it to move. I looked at actual dyno runs for these 230bhp claimed cars, I'm sure that's at the flywheel as loads of runs are no where near that. Depending on variables, they seem to produce 165bhp - 185bhp, I saw one at 190bhp. It explains why it didn't feel fast. This is all at 8200rpm, at 4500rpm it's about 120bhp and at 3000rpm nothing is worth mentioning. In my opinion it would be better suited for racing, I drive to and from work and social driving so I want the low end grunt and great sound, not the sound of a 2 stroke moped.
Engine measurements were taken from the bellhousing to the crank pulley, the KLDE is 1 inch longer. The gearbox was always bolted to the beam, that's the datum. The V6 is in with minimal cutting to the bulkhead.
From the 8's ecu, I'm only using the crank signal, water temp and oil presure to work the dash, share the signal to a stand alone ecu.

kickerfox

I don't know where others get that swaps are unreliable. Maybe it's crappy work because an engine doesn't care what it's in. 100k miles is easily obtainable by just about anything but a renesis.

-subbed-

KFC

Absolutely! I started a new thread as I had no interest on my other one and it was closed because I put it in the section.
There are purist on here and that's fine, they won't like the renesis compared to the sound of a moped. Oh, I am thinking of having a later mod, electric powered turbo, there's someone I know that is working on one on his MX6.

kickerfox

Brushless DC? The ones like the pic below do 20psi@250cfm and another at 63psi@250cfm. AMETEK PMC makes them.

9krpmrx8

iTrader: (46)

Show me a swapped RX-8 with 100,000 miles post engine swap. Or hell, 30,000 miles post swap. When you too knuckle heads are finished with your builds we should set up a track day and see just how fast these clusterf#$ks are.

RIWWP

iTrader: (2)

I'm not upset, I just don't understand your logic. Your explanation is all inaccurate anyway.


"BHP" is at the flywheel. By definition. A healthy 6-port RX-8 will produce about 200whp, which is power rated at the wheels. Big difference, since BHP does not take into account the drivetrain losses from needing to spin the transmission, transmission fluid, driveshaft, diff, diff fluid, axles, hubs, wheels, and tires. WHP accounts for all of that, so it will ALWAYS be a lower number.

Not BHP, WHP. And yes, a 165whp RX-8 is one with an unhealthy engine.

I'm guessing that's a typo...

If a 3,000lb car with 230bhp doesn't feel fast, what makes you think a 3,000lb car with 210bhp is faster? That is the swap you are trying to do.

Have you considered just purchasing a car with those attributes in the first place?


Again, not upset, just challenging your logic ... which has quite a few holes in it.



100,000 miles is easily obtainable in a Renesis as long as you don't ignore the car.

The reliability we talk of for swaps is not the engine blowing up, but of everything else related to the swap. Even the completed swaps are constantly trying to solve random issues related to the swap, or have persistant issues that are just ignored. That ISN'T "reliable".

kickerfox

Even with maintenance records to show, they are unreliable FROM THE FACTORY. With changes to the tune you can probably get more.

Perhaps reliability takes a little more talent then just "swapping an engine" using crap ebay parts. That's why I'm using as many OEM parts as possible in my swap.

The whole power argument isn't just numbers (or graphs). Your psychological butt dyno says otherwise. I thought my '86 TPI Firebird was fast with it's whopping 205hp but the torque made it feel like it was more. Jumping stopsign to stopsign was a blast but once it hit 4500rpm, or 3rd gear, the fun was over.

One thing about high RPM engines you can't argue are the drivetrain losses are significantly higher. Those physics work like a boat on water. Say your torque was constant and your horsepower came from RPM. Say 100hp crank@4000rpm nets 80rwhp, then 200hp crank@8000RPM nets 140rwhp (not 160hp). Just an example but it works like that. A slower turning v6 making 238hp WILL be faster then a 238hp Renesis since it will make more wheel horsepower. Plus it gets the launch.

I'm with KFC on this. I'm sure he's crunched the same numbers I have and came to the same conclusion.

...this guy. Swaps haven't been around as long as the 8 has. Starting in '04, lets average 10k a year. That brings us to 100k in 2014. 8's have been dropping like flies around 80k so lets say 8 years. That gets us to 2012. Lets add 1yr for the swap to take place. We're now at 2013 when the swap hit the road. So today the swap has 10k on it. Get back to me in 9 years.

9krpmrx8

iTrader: (46)

WAT. Show me a swap with high mileage, hell I will even let you include rotary swaps.

kickerfox

If ****'s breaking it's because you used **** parts or did a **** job installing it. Difficult concept? There's quite a few hack "mechanics" out there. They fall right into the swap category too. As for shops doing it? There's not enough money in engine swaps to put out the effort required for a 100k mile quality.

Good luck KFC! I'm going back to argue on my build thread.

KFC

I you have actually SEEN the inside of a worn renesis, you wouldn't think that or say it.

KFC

Agreed!! I somehow think these people aren't engineers or good mechanics. Don't really know the real world rather than just reading stats and graphs. 😜

KFC

Quote:
Originally Posted by KFC
I drive to and from work and social driving so I want the low end grunt and great sound, not the sound of a 2 stroke moped.
Have you considered just purchasing a car with those attributes in the first place?


Again, not upset, just challenging your logic ... which has quite a few holes in it.

Holes in my logic? WOW!
I question your profession? What do you do for work? You have no idea what I do. Again, this is fun for me as I can apply my wealth of engineering experience and skills, it's cost saving as well, my budget is more than half the price of "JUST" buying something similar, that would be boring.

RIWWP

iTrader: (2)

So with some maintenance and a $500 tune adjustment, you agree that you can get a factory Renesis reliable to over 100,000? Vs a $20,000+ engine swap?



You are talking about area under the power curve, and that's something I entirely get. The RX-8 actually has alot of it. High torque doesn't always mean anything. I had a PT Cruiser rental that would spin the tires off the line with even slight gas input, and as soon as the RPMs started climbing I would look behind me to see what trailer it felt like it was pulling. Behind able to hold torque through the RPM range is what makes that power under the curve. I agree on drivetrain losses, it's one of big loss areas for the RX-8.

I think you prove our point here. If the cost is prohibitive to get 100,000 mile quality, than the swap isn't worth doing? So if you are doing a swap, then you must be taking cost cutting measures to make it worth doing, ie, the reliability won't be there for a 100,000 mile swap. Yes, you are doing your own swap yourself, and that saves a lot, but so far you are how many years and how many dollars in the hole that you can never recover before you can even start counting miles? Vs just getting another $3,300 engine.

Um, he has. He has rebuilt quite a few, and done so properly. He shares more internal engine pictures than anyone else on this site. He has a really good grasp on what is required. He doesn't just throw his hands up in the air saying "this is impossible because I didn't do something right".



Oh the irony. There is an community joke about Kickerfox and his graphs...


We do know the real world, and those real world points are the ones we are bringing up. There is ONE completed swap that we could call reliable, and it was an LS2 swap done by TogueFactory, and the customer was apparently a dealership that did it for some sort of marketing deal, and they have been trying to sell the car for $69,000 for a few years now. We don't know that it is actually reliable, but given the quality of the work, it's not hard to believe that it will be. Literally no other swap has ever been completed that has been reliable. LS, 5.0, 2JZ, 20B, 26B. Every single "completed" swap has bounced between owners, each one having a laundry list of problems that people think will be easy to solve, but then find out it can't be, and sell off the car again. The exception might be the swaps in Pakastan, but those literally just rip all the electronics out of the car, to bypass the problem rather than solving it, since they apparently don't have vehicle regulations to deal with.

That is our 'real world'. Tens of thousands and months if not years of work for a swap to get a car that is even more unreliable. Our real world perspective will indeed change, once people start reversing that. So far, it never has. Every single swap continues to prove out the accuracy of what we are saying.

If you want to be that exception, then more power to you. But you can get 300,000 miles out of an RX-8 for less than the cost of a single swap. Or you can just go buy a car with the engine you want in the first place for even less. So going through a long expensive swap to gain reliability is simply wearing blinders. Some real world perspective would go a long way toward helping you to your goal.

RIWWP

iTrader: (2)

Since when does profession have to do with logic? I could be a janitor and still know that one number is bigger than another number.

If you are doing this "just for fun", then I can understand that. But that's not the reasoning that you started with, which was the reasoning I was replying to. Your original reasoning was that the 228bhp engine wasn't fast enough, so you were putting in a 210bhp engine. Regardless of what your profession is, i think you have to see an inconsistency there. Ie, a hole in your logic.

KFC

[QUOTE=RIWWP;4633661]So with some maintenance and a $500 tune adjustment, you agree that you can get a factory Renesis reliable to over 100,000? Vs a $20,000+
My engine is still in my car that I've had for 2 years on LPG that I bought for £400, the RX8 I bought for £350, my budget is £2000, not $20000. You must not be doing the work yourself or car parts are very expensive is the US!!😝

200.mph

iTrader: (9)

says the guy who is sourcing parts from 6+ different manfactures

first off 9k has more experience than 99% of people on this site when it comes to the renny and has torn down/rebuilt a few and his build is pretty epic.

riwwp is a wealt of knowledge and a pleasure to have here. hes a true gear head that understands what works.

RIWWP

iTrader: (2)

$20,000 USD does not equal 20,000 UK pounds. You will go over budget for it to be reliable

Posted From RX8Club.com Android App

Vlaze

iTrader: (14)

A good engineer uses concurrent engineering and/or takes council to work with those who have expertise in the area when they lack it whether through extensive thorough reading or working real-time with those individuals. While I presume you have read up on the material I think you're ignoring a lot of knowledge from those here who have a much more extensive background working on this car than you regardless of their profession which is irrelevant.

You'll have to excuse 9k; while many times he makes good points he often comes off initially as an a-hole typically because he's seen a boat load of threads like this over the years and his tolerance for them have maxed out.

Apparently you haven't taken into account the 2x extra weight of that engine you're swapping in place adds to the car now diminishing your speculated returns even more not to mention the rest of the hardware you'll be adding to make it fit and work properly.

Add to the fact your handling is now gone for the worst on a car that had top-notch handling means you either want this just for a straight line or are willing to spend even more money now to get the handling back to where it should be optimally.

Lastly, lose the ego and stop giving us who do actual engineering for a living a bad name; it makes it sound like we think everything done on paper and in theory is the best thing ever without actually testing it. Best of luck to you.

Kthxbai.

9krpmrx8

iTrader: (46)

I am certain I have more experiences than you do with the Renesis. I have torn apart a few and have had four of my own so I am well aware of how reliable and how unreliable they can be. They can fail in a number of ways, just like any other engine, especially when you start making serious modifications (such as kickers turbo dreams). But as RIWWP pointed out, we are not talking about just engine reliability.

You sound like you have your mind made up so rock on. But I won't hold my breath, these type of swaps never get finished. The only legitimate piston engine swap into an RX-8 that I can think of recently that looks to be a solid build is north $25,000.00 and is not even finished yet.