Rx8 swap kits?

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Discussion

GTdrive

Original Poster:

165 posts

58 months

Tuesday 21st January 2020
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I often see RX8s with a blown engine up for sale. Quite a few really. They do seem to have the tendency to go bust. With such a trend and given the chassis seems to be praised, has anybody developed an easy and affordable kit to install another used japanese engine in these cars? It seems a pity to see so many of them going to the scrap. Probably any other Japanese engine would be more reliable and give them a second life.

Rotary Potato

376 posts

103 months

Wednesday 22nd January 2020
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I think part of the issue with doing that is that the engine is a contributing factor to why the chassis is so praised. It's very light (for a 200bhp+ engine) and very compact (again, for a 200bhp+ engine) and that allows it to be sat very far back and very low in the chassis.

If you were to drop in a similarly powerful, but less grenade'y, engine you'd have more weight in a less advantageous position in the chassis. That would negatively impact the handling, and you'd need to do significant work (development work + whatever the final component cost of the solution was) to claw back the lost handling performance - significantly bumping up the price of a conversation kit that was all upside and no downside.

However, it is horses for courses, and I'm sure there's a section of society who have no real interest in the handling of a car (beyond getting them safely from A to B) and would like an RX8 if only it was more reliable and did better MPG. For these people a kit to drop another engine in would be just fine. Whether that group is big enough to make a conversion kit worthwhile, isn't something I could answer.

I wonder why you limit your thinking just to Japanese engines? If you're going to alter the character of an RX8 by replacing the rotary engine, I don't see how the country of origin of the donor engine matters. Surely you'd go for whatever engine met your cost vs performance criteria best. I've heard of all sorts from Chevy LS V8s, through SAAB turbo 4-pots to 2JZ engines dropped into an RX8 chassis. I'm sure they'd all be fun in different ways, and all have their own character ... but none of them would be an RX8.

GTdrive

Original Poster:

165 posts

58 months

Wednesday 22nd January 2020
quotequote all
Rotary Potato said:
I think part of the issue with doing that is that the engine is a contributing factor to why the chassis is so praised. It's very light (for a 200bhp+ engine) and very compact (again, for a 200bhp+ engine) and that allows it to be sat very far back and very low in the chassis.
How much the engine weighs?

Rotary Potato said:
If you were to drop in a similarly powerful, but less grenade'y, engine you'd have more weight in a less advantageous position in the chassis.
What if it was a Subaru boxer? They are low center of gravity too. No idea how reliable or how powerful though as I was never a Suburau fan. But I know the boxers are lower center.

Rotary Potato said:
That would negatively impact the handling, and you'd need to do significant work (development work + whatever the final component cost of the solution was) to claw back the lost handling performance - significantly bumping up the price of a conversation kit that was all upside and no downside.

However, it is horses for courses, and I'm sure there's a section of society who have no real interest in the handling of a car (beyond getting them safely from A to B) and would like an RX8 if only it was more reliable and did better MPG. For these people a kit to drop another engine in would be just fine. Whether that group is big enough to make a conversion kit worthwhile, isn't something I could answer.
So are you saying kits don't exist then? This would surprise me, given how many end up being scrapped because of blown engines and given several cars have many kits available like the MX5.

Rotary Potato said:
I wonder why you limit your thinking just to Japanese engines? If you're going to alter the character of an RX8 by replacing the rotary engine, I don't see how the country of origin of the donor engine matters. Surely you'd go for whatever engine met your cost vs performance criteria best. I've heard of all sorts from Chevy LS V8s, through SAAB turbo 4-pots to 2JZ engines dropped into an RX8 chassis. I'm sure they'd all be fun in different ways, and all have their own character ... but none of them would be an RX8.
I'm not limiting it to Japanese engines. I just don't want a V8. Too much in my opinion. wink

Thanks for replying.

old'uns

550 posts

140 months

Wednesday 22nd January 2020
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Rotary Potato

376 posts

103 months

Thursday 23rd January 2020
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GTdrive said:
Rotary Potato said:
I think part of the issue with doing that is that the engine is a contributing factor to why the chassis is so praised. It's very light (for a 200bhp+ engine) and very compact (again, for a 200bhp+ engine) and that allows it to be sat very far back and very low in the chassis.
How much the engine weighs?

Rotary Potato said:
If you were to drop in a similarly powerful, but less grenade'y, engine you'd have more weight in a less advantageous position in the chassis.
What if it was a Subaru boxer? They are low center of gravity too. No idea how reliable or how powerful though as I was never a Suburau fan. But I know the boxers are lower center.

Rotary Potato said:
That would negatively impact the handling, and you'd need to do significant work (development work + whatever the final component cost of the solution was) to claw back the lost handling performance - significantly bumping up the price of a conversation kit that was all upside and no downside.

However, it is horses for courses, and I'm sure there's a section of society who have no real interest in the handling of a car (beyond getting them safely from A to B) and would like an RX8 if only it was more reliable and did better MPG. For these people a kit to drop another engine in would be just fine. Whether that group is big enough to make a conversion kit worthwhile, isn't something I could answer.
So are you saying kits don't exist then? This would surprise me, given how many end up being scrapped because of blown engines and given several cars have many kits available like the MX5.

Rotary Potato said:
I wonder why you limit your thinking just to Japanese engines? If you're going to alter the character of an RX8 by replacing the rotary engine, I don't see how the country of origin of the donor engine matters. Surely you'd go for whatever engine met your cost vs performance criteria best. I've heard of all sorts from Chevy LS V8s, through SAAB turbo 4-pots to 2JZ engines dropped into an RX8 chassis. I'm sure they'd all be fun in different ways, and all have their own character ... but none of them would be an RX8.
I'm not limiting it to Japanese engines. I just don't want a V8. Too much in my opinion. wink

Thanks for replying.
Hi there,

A fair bit there ...

How much does it weigh? - unsure. I can just about lift one off the ground with flywheel on. But I do have skinny spaghetti arms and am not very good at things like that. I can't imagine any similarly powerful engine that's commonly and cheaply available coming close for weight.

Subaru boxer engine? - very wide ... may not be able to fit low down in the engine bay without significant cutting of the bodyshell. This is a guess based on gut feeling. I've never seen an EJ20 or similar in an RX8 so can't say for certain. Even if you can mount it nice and low, it'd still be significantly more weight than stock, so likely a backwards step in terms of handling.

Am I saying engine conversion kits don't exist? Definitely not saying that. But you were asking for an "easy and affordable" kit ... and I don't know of any of those. Most of what I was saying was not so much around the process of sticking a different engine in the engine bay, but about the chassis compromises doing that would almost certainly bring, and the work that would be required to address that.

As for engine choice, if it were me, I'd accept that I was buggering up the chassis balance regardless of choice, so might as well go all in for a big bhp aluminium american crate V8! biggrin Appreciate that's a completely personal choice though.

GTdrive

Original Poster:

165 posts

58 months

Thursday 23rd January 2020
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I'm not looking for a track car. So if it ruined a percentage of the handling it would be fine by me. I don't think it would be horrible.

I'm looking for a daily driver. I want something RWD, manual and a bit fun, within budget. For something a bit more special I could stretch the budget a bit. So I was just asking as I had no idea how developed the swap market was for the RX8. Maybe somebody had come up with a kit to be used with one of the widely available and affordable engines. I was not sure, so I asked.

A V8 in a daily driver is just overkill.

delta0

2,392 posts

113 months

Saturday 25th January 2020
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You are looking at about 90kg for the engine on its own. It is compact and fits behind the front wheels making the RX8 a mid engined car. There is a lot of space and I have seen various other engines fitted to this car but as mentioned you will lose the balance of the car as the engine weight will go up and it will go forward.

Edited by delta0 on Saturday 25th January 09:20

GTdrive

Original Poster:

165 posts

58 months

Saturday 25th January 2020
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I'm not too worried about perfect handling. If it handles now like a sports car and after the swap it would handle like a GT, I would be perfectly fine with that. I doubt it would start handling like a barge.

I'm after a fun daily driver. I'm not sure how smart is to daily drive a rotary RX8. Specially at this point in the life of the car. But besides the engine, the rest checks all boxes. RWD, manual, fun, back seats and even rear doors.

So the handling is not the dear breaker. Cost for a swap would be.

1430

81 posts

124 months

Friday 31st January 2020
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Why it's such an ugly car?
Maybe they would be good cars if the previous rx7 didn't beat it in every department.

GTdrive

Original Poster:

165 posts

58 months

Wednesday 5th February 2020
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1430 said:
Why it's such an ugly car?
Maybe they would be good cars if the previous rx7 didn't beat it in every department.
Beauty is in the eye of the beholder.

RX7 FD is now way overpriced for what it is. RX8 is also infinitely more practical.

Rotaries are trouble no matter what .RX7, RX8 doesn't matter.

1430

81 posts

124 months

Thursday 6th February 2020
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GTdrive said:
Beauty is in the eye of the beholder.

RX7 FD is now way overpriced for what it is. RX8 is also infinitely more practical.

Rotaries are trouble no matter what .RX7, RX8 doesn't matter.
I think the RX7 has the looks and power to warrant a bit of unreliably, the RX8 doesn't really have anything to offer expect price.

Rotary Potato

376 posts

103 months

Friday 7th February 2020
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1430 said:
Why it's such an ugly car?
Maybe they would be good cars if the previous rx7 didn't beat it in every department.
Ummm ... not sure you're comparing apples with apples here. smile

The RX7 FD (the one I assume you are referring to) and RX8 were very different cars, aimed at very different markets. The RX7 was pitched at the high end, competing against Porsche 911s, Honda NSXs and the like.

The RX8 was a completely different segment of car - competing against things like the Alfa Romeo GT, Audi TT and the like.

If you just looked at performance and handling, there's a solid argument that the RX8 performed better than its rivals (Alfa GT, Audi TT, etc.) than the RX7 did against its rivals (911, NSX, etc.). The difference being that poor fuel economy and questionable reliability are better tolerated by the high end segment than the lower end segment.

Looks are entirely subjective. Different people like different things ... no one is right or wrong. If you don't like the look of the RX8, that's OK ... but don't assume that just because you think something that everybody else also has to.

irocfan

42,391 posts

197 months

Friday 7th February 2020
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an interesting aside here (since I know you don't want a V8). RX8 Rotary about 114kg, Chevy LS series from about 160kg (an LS2 comes in at 200kg)

GTdrive

Original Poster:

165 posts

58 months

Friday 7th February 2020
quotequote all
1430 said:
I think the RX7 has the looks and power to warrant a bit of unreliably, the RX8 doesn't really have anything to offer expect price.
Says you I guess. smile

GTdrive

Original Poster:

165 posts

58 months

Friday 7th February 2020
quotequote all
Rotary Potato said:
Ummm ... not sure you're comparing apples with apples here. smile

The RX7 FD (the one I assume you are referring to) and RX8 were very different cars, aimed at very different markets. The RX7 was pitched at the high end, competing against Porsche 911s, Honda NSXs and the like.

The RX8 was a completely different segment of car - competing against things like the Alfa Romeo GT, Audi TT and the like.

If you just looked at performance and handling, there's a solid argument that the RX8 performed better than its rivals (Alfa GT, Audi TT, etc.) than the RX7 did against its rivals (911, NSX, etc.). The difference being that poor fuel economy and questionable reliability are better tolerated by the high end segment than the lower end segment.

Looks are entirely subjective. Different people like different things ... no one is right or wrong. If you don't like the look of the RX8, that's OK ... but don't assume that just because you think something that everybody else also has to.
I agree with you. I think you are spot on. Except for the cars you see the RX7 competing against. I never saw the RX7 FD as a Porsche 911 competitor and specially not the NSX. The NSX was in a much higher price bracket too.

I think the RX7 FD competed with the cheaper Porsches like the 944 and 968. And against the 300ZX, Supra etc.

But yes, the RX7 and RX8 are totally different cars for totally different segments. The RX8 was a sporty daily driver. The RX7 was a sports car. Not practical at all as a daily unless you are in high school.

I again agree that the RX8 beat its competition performance wise. It is definitely more fun to drive too than an Alfa GT, except perhaps the V6 because of that unmatched noise and rev hunger. But definitely more fun than the other Alfa it competed with, the Brera. Loads more fan the Golf in drag FWD TT. Loads more fun than any Civic with their FWD or the Toyotas too. And apparently it out-handled all of them as well.

I think this might have been part of the problem. Many saw the RX8 as the next RX7 and for that they thought it was an all out sports car. But that wasn't the intention at all. I mean, it has "4 doors".

About the looks, I think the last facelift cars are very good looking. There's an air of expensive European car to the late cars. I don't know what it is. But I like it.

GTdrive

Original Poster:

165 posts

58 months

Friday 7th February 2020
quotequote all
irocfan said:
an interesting aside here (since I know you don't want a V8). RX8 Rotary about 114kg, Chevy LS series from about 160kg (an LS2 comes in at 200kg)
Well, is there a ready to go, DIY, bolt on LS swap kit for the RX8? Something no frills no hassle?

But I'm sure that a V8 ruins the handling and turns the car into a straight line warrior? Looking at photos it is a huge engine, much larger than the wankle and sits considerably forward from the front axle, compared to the wankle.

Yes, I said I don't care for perfect handling since it would be a daily. But if I'm going to put up with the V8, I would want good handling still.

Edited by GTdrive on Friday 7th February 13:49

irocfan

42,391 posts

197 months

Friday 7th February 2020
quotequote all
GTdrive said:
irocfan said:
an interesting aside here (since I know you don't want a V8). RX8 Rotary about 114kg, Chevy LS series from about 160kg (an LS2 comes in at 200kg)
Well, is there a ready to go, DIY, bolt on LS swap kit for the RX8? Something no frills no hassle?

But I'm sure that a V8 ruins the handling and turns the car into a straight line warrior? Looking at photos it is a huge engine, much larger than the wankle and sits considerably forward from the front axle, compared to the wankle.

Yes, I said I don't care for perfect handling since it would be a daily. But if I'm going to put up with the V8, I would want good handling still.

Edited by GTdrive on Friday 7th February 13:49
a bolt in LS swap kit? I'm pretty sure that there is - the Yanks love putting it in everything! That doesn't help you much over here though, I was just surprised by the (relatively) small weight differential (IIRC the LS is also not a 'tall' engin which also adds to the flexibilitye)

Rotary Potato

376 posts

103 months

Friday 7th February 2020
quotequote all
irocfan said:
an interesting aside here (since I know you don't want a V8). RX8 Rotary about 114kg, Chevy LS series from about 160kg (an LS2 comes in at 200kg)
Not sure I believe that weight for the rotary, seems too heavy. I'm fairly sure I can't lift 100+ kilos off the floor, but I can (just) lift a 13B.

The problem with weights quoted on the internet is they rarely state what is/isn't included ... bare block, inlet, exhaust, flywheel, alternator, a/c, etc.

Or maybe it is right & I'm just stronger than I give myself credit for!

I do know (because I measured) that from base of sump to the bracketry on top of the block is under 60cm. I'd guess base of sump to top of engine is about 50cm. So whatever weight is there is very low down in the car.


Rotary Potato

376 posts

103 months

Friday 7th February 2020
quotequote all
GTdrive said:
I agree with you. I think you are spot on. Except for the cars you see the RX7 competing against. I never saw the RX7 FD as a Porsche 911 competitor and specially not the NSX. The NSX was in a much higher price bracket too.

I think the RX7 FD competed with the cheaper Porsches like the 944 and 968. And against the 300ZX, Supra etc.

But yes, the RX7 and RX8 are totally different cars for totally different segments. The RX8 was a sporty daily driver. The RX7 was a sports car. Not practical at all as a daily unless you are in high school.

I again agree that the RX8 beat its competition performance wise. It is definitely more fun to drive too than an Alfa GT, except perhaps the V6 because of that unmatched noise and rev hunger. But definitely more fun than the other Alfa it competed with, the Brera. Loads more fan the Golf in drag FWD TT. Loads more fun than any Civic with their FWD or the Toyotas too. And apparently it out-handled all of them as well.

I think this might have been part of the problem. Many saw the RX8 as the next RX7 and for that they thought it was an all out sports car. But that wasn't the intention at all. I mean, it has "4 doors".

About the looks, I think the last facelift cars are very good looking. There's an air of expensive European car to the late cars. I don't know what it is. But I like it.
Evo magazine appear to disagree with you. smile

"Launched in the UK in a single high specification to rival the Porsche 911 ..."

"The RX-7 produced 237bhp upon its release in the UK, but thanks to a lithe kerb-weight was hardly lacking against more powerful rivals like the Toyota Supra, Honda NSX and Nissan Skyline GT-R."

https://www.google.co.uk/amp/s/www.evo.co.uk/mazda...

Either way, we both agree that the RX7 FD & RX8 are cars in very different segments with very different rivals.

GTdrive

Original Poster:

165 posts

58 months

Saturday 8th February 2020
quotequote all
All I'm saying is, if I was looking at a 911 back then, I would not look at a RX7 as an alternative. They are not on the same level in my opinion.