My RX8 VAG 20v project.

My RX8 VAG 20v project.

Author
Discussion

dom9

8,090 posts

210 months

Saturday 1st March 2014
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Isn't the S2000 lump a massive improvement in relaibility though? Can also add forced induction for mega-power [devil's advocate]

Disco You

3,685 posts

181 months

Saturday 1st March 2014
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Fastdruid said:
Disco You said:
Something like a honda s2000 lump would work well in an RX-8 I think.
Why? 9 extra HP, less torque, more weight, 4mpg better and the loss of the DSC/traction control. Hardly really worth it for the cost.

If you're going to do an engine swap it needs to be a real improvement or cheap.
Oh, I thought they were more powerful that that. I guess that the reliability and better economy are large plus points though.

Maybe an s2000 engine with forced induction, then wink

mighty kitten

431 posts

134 months

Saturday 1st March 2014
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I've made some parts for a guy who's fitted a Saab b234 in his rx8 using an omega gearbox . The massive electric steering rack is the biggest issue and he built a new frame with a mk2 escort quick rack coupled to a corsa epas powered Column . The box may have issues once its running over 300hp but so far had been a very cheap conversion . Build thread is on uk saabs

mighty kitten

431 posts

134 months

Saturday 1st March 2014
quotequote all
I've made some parts for a guy who's fitted a Saab b234 in his rx8 using an omega gearbox . The massive electric steering rack is the biggest issue and he built a new frame with a mk2 escort quick rack coupled to a corsa epas powered Column . The box may have issues once its running over 300hp but so far had been a very cheap conversion . Build thread is on uk saabs

Fastdruid

8,652 posts

153 months

Saturday 1st March 2014
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dom9 said:
Isn't the S2000 lump a massive improvement in reliability though? Can also add forced induction for mega-power [devil's advocate]
So what if it is?

You're going to spend a fortune to fit it, at cheapest it's going to be something like 5k and an RX-8 rebuild (with warranty) is £2500. Given that it seems about 50-60k is when RX-8's _might_ need a rebuild you're talking at 100-120k before you 'break even'.

On the plus side it does bolt straight up to the gearbox and you can tune it to ~400hp (although you could also turbo the Renesis to 400HP)

I agree that of all the engines out there it's the closest in character but for that reason I don't see the point.

Still don't know of anyone who's done it.

Scottr89

51 posts

123 months

Sunday 2nd March 2014
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What about the straight 6 from an E46 M3? Might cost a bit more but would add so much more appeal to the car, YB cossie engine, SR20? Other then that I agree with the S2000 engine, right chassis for the job!

Edited by Scottr89 on Sunday 2nd March 07:46

snotrag

14,478 posts

212 months

Sunday 2nd March 2014
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If your going to pit a 4pot in then surely the obvious choice is the 2.0 MZR out of a Mk3 MX5,as in the engine a 2ltr duratec is based on. They can be boosted easy, and I guess would be an easier fit as the RX8 and MX5 share a bit (gearbox even?).
There's also the 2.3 versions that come in Malta 6's?

So long as it fits under the bonnet....?

(but really a 4 banger in an RX8 is daft, V8 or nothing IMO).

Fastdruid

8,652 posts

153 months

Sunday 2nd March 2014
quotequote all
snotrag said:
If your going to pit a 4pot in then surely the obvious choice is the 2.0 MZR out of a Mk3 MX5,as in the engine a 2ltr duratec is based on. They can be boosted easy, and I guess would be an easier fit as the RX8 and MX5 share a bit (gearbox even?).
There's also the 2.3 versions that come in Malta 6's?

So long as it fits under the bonnet....?

(but really a 4 banger in an RX8 is daft, V8 or nothing IMO).
The turbocharged 2.3 engine out of the MPS surely. smile

But the RX-8 drivetrain pretty much slots into the MX-5 so it should also go the other way round. Not sure about the gearbox though.

otolith

56,242 posts

205 months

Sunday 2nd March 2014
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Fastdruid said:
But the RX-8 drivetrain pretty much slots into the MX-5 so it should also go the other way round. Not sure about the gearbox though.
I would think any four cylinder lump is going to be a little longer and a lot taller than the renesis. It sits so low down and virtually under the dashboard that height may be an issue - if it is then you're stuck with moving it forward, which I guess you can do because there's an awful lot of empty space in front of the engine, but you are then getting away from the front mid-engine weight distribution that makes the thing handle well in the first place.

davepoth

29,395 posts

200 months

Sunday 2nd March 2014
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otolith said:
Fastdruid said:
But the RX-8 drivetrain pretty much slots into the MX-5 so it should also go the other way round. Not sure about the gearbox though.
I would think any four cylinder lump is going to be a little longer and a lot taller than the renesis. It sits so low down and virtually under the dashboard that height may be an issue - if it is then you're stuck with moving it forward, which I guess you can do because there's an awful lot of empty space in front of the engine, but you are then getting away from the front mid-engine weight distribution that makes the thing handle well in the first place.
NC MX-5 and the RX-8 are on the same floorpan by all accounts, so it should work. The critical thing with such things is the location of the crash structure and the top mounts for the front suspension, and it's unlikely they'll have re-engineered those.

otolith

56,242 posts

205 months

Sunday 2nd March 2014
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I don't think the platform sharing goes much beyond some commonality in suspension components. Have a look at a photo of an NC MX-5 engine in place, and at an RX-8 engine with all the plastic covers removed and you'll see what I'm getting at.

Fastdruid

8,652 posts

153 months

Sunday 2nd March 2014
quotequote all
Supercharged Renesis into an MX-5 project smile

http://www.rx8club.com/australia-new-zealand-forum...

No cutting apart from the torque tube and driveshaft, pretty much just bolt it in.

Post 16 shows the Renesis in an MX-5


Edited by Fastdruid on Sunday 2nd March 21:42

otolith

56,242 posts

205 months

Sunday 2nd March 2014
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Yeah, Renesis into MX-5. Half pint into pint pot is also simple!

petey1979

Original Poster:

27 posts

127 months

Monday 3rd March 2014
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good to see some positive feedback, I have already made a prototype adaptor plate from 10mm allu (turned out about 3mm off centre on the shaft so wont do for a final piece but it gave me the opportunity to get everything lined up where I wanted it.

yes it does involve a massive bit of bulkhead chopping but the engine sits back where it should behind the axle so hopefully the chassis setup will not be affected (from the info I could gather they weigh virtually the same?)

the 20v is a short block in terms of longitudal length (pulley to flywheel) its a little taller the rotary but there is till loads of under the hood.

ive just spent the last few days building an exhaust manifold so that's one thing off the list.

i'll post a project thread up in the Japanese section soon.

pete

petey1979

Original Poster:

27 posts

127 months

Monday 3rd March 2014
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Right i'll make a start of this thread then given some may actually want to see one finished haha.

please bear in mind this is a budget build, it could all be easily done by throwing a pile of cash at it (as can anything)

this is how I bought the car in sept last year, cost me £500 delivered. came with no engine and some wiring missing (sorted now) so was an ideal base for me.

bose sounds,6 speed box, alcantara not leather seats and no sat nav




petey1979

Original Poster:

27 posts

127 months

Monday 3rd March 2014
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and here's how it currently sits


petey1979

Original Poster:

27 posts

127 months

Monday 3rd March 2014
quotequote all
how far the engine sits into the car, some modification to the heater box should see the whole dash back no probs.



waaay back behind the axle



where the turbo will sit, did think it would look better with the turbine inlet underneath but this was how it had to go. excuse the welding, I just tacked it and had it welded properly across the road from me, will upload some pics when it looks pretty



home made manifold flange from 10mm steel cut using a hole saw I might add



start of the manifold build





next on the list is subframe, will be mostly tubular with custom mounts for the (as yet to be found) steering rack as the rx8 one is mahoosive and hits the bottom pulley.

petey1979

Original Poster:

27 posts

127 months

Monday 3rd March 2014
quotequote all
From your post I'd guess it's in the wrong place......
Could see where else to put it??
Thought this was mazda in general

petey1979

Original Poster:

27 posts

127 months

Monday 3rd March 2014
quotequote all
did you delete the other thread?

if you'd had said you moved this one I wouldn't have reposted in the mx5 forum.

I'll sort it cheers

EggsBenedict

1,770 posts

175 months

Monday 3rd March 2014
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Keep going here - lots of project threads here.

Good effort - look forward to more updates