MX-5 engine swap
Discussion
Hey all, its my first time in this corner of PH so go easy on me!
My ex-housemate has a mk2 mx5 that she is looking to get rid of and I'm thining of buying. Now its only the 1.6 but I'm very tempted to get it any way and enjoy it for what it is, a small, low powered, rear-wheel drive soft top at a knock down price.
Like any slightly discontented person though, I'm already thinking of trying to up the power, mainly because I've been on bikes for a while and am worried that the 1.6 could feel slowwwwwwwwwwwwwww.
I posted recently in GG on this topic and they suggested forced induction, which sounded good and I had a look around. But then an idea occured to me that may be completely mad, but I'm wondering if people have tried putting the small V6 from the MX-3 into an MX-5? I think its only a 1.8 and being honest I don't see the point of a V6 that small but maybe it would be ripe for tuning?
Do they fit under the MX-5's bonnet and has anyone done one of these. Would it affect weight distribution and then handling, balance etc.?
Also, do people do engine swaps or just tune the original lump?
Sorry for the epistle, I've got way too much free head space in my job!
Ta,
NN
My ex-housemate has a mk2 mx5 that she is looking to get rid of and I'm thining of buying. Now its only the 1.6 but I'm very tempted to get it any way and enjoy it for what it is, a small, low powered, rear-wheel drive soft top at a knock down price.
Like any slightly discontented person though, I'm already thinking of trying to up the power, mainly because I've been on bikes for a while and am worried that the 1.6 could feel slowwwwwwwwwwwwwww.
I posted recently in GG on this topic and they suggested forced induction, which sounded good and I had a look around. But then an idea occured to me that may be completely mad, but I'm wondering if people have tried putting the small V6 from the MX-3 into an MX-5? I think its only a 1.8 and being honest I don't see the point of a V6 that small but maybe it would be ripe for tuning?
Do they fit under the MX-5's bonnet and has anyone done one of these. Would it affect weight distribution and then handling, balance etc.?
Also, do people do engine swaps or just tune the original lump?
Sorry for the epistle, I've got way too much free head space in my job!
Ta,
NN
Hmm, wonder if the Alfa lump is too tall?
As for the V6, the MX3 lump is based on the same block as the MX6 lump, the KL (-Z I think)(UK versions had 170 bhp, it's 2.5l 24 valve with variable induction) - if you can get the Jap import version in KL-ZE form (careful since they also had a 2.0 l version, and a 2.5 'normal one) then 200 bhp are yours.
I think the more cost effective option is forced induction on the 1.6. Also the version you speak of I think will be the 90 bhp one - apparently the heads are the same, but not sure the pistons and cams are different from the early, 116 bhp Mk 1 1.6.
I had the MX6 for a while, and wasn't over impressed by the engine, it was thristy, had a nice flat spread of power/torque, was smooth, and not happy that in the first week of ownership it threw a rod through the sump... Think looking at all the toys on it a few more gg's would have been appreciated! It is all alloy though.
As for the V6, the MX3 lump is based on the same block as the MX6 lump, the KL (-Z I think)(UK versions had 170 bhp, it's 2.5l 24 valve with variable induction) - if you can get the Jap import version in KL-ZE form (careful since they also had a 2.0 l version, and a 2.5 'normal one) then 200 bhp are yours.
I think the more cost effective option is forced induction on the 1.6. Also the version you speak of I think will be the 90 bhp one - apparently the heads are the same, but not sure the pistons and cams are different from the early, 116 bhp Mk 1 1.6.
I had the MX6 for a while, and wasn't over impressed by the engine, it was thristy, had a nice flat spread of power/torque, was smooth, and not happy that in the first week of ownership it threw a rod through the sump... Think looking at all the toys on it a few more gg's would have been appreciated! It is all alloy though.
Why not just buy an MX5 with a blower already installed?
Like this http://www.pistonheads.com/sales/697343.htm
ETA - not mine, just browsed over it
Like this http://www.pistonheads.com/sales/697343.htm
ETA - not mine, just browsed over it
Edited by paulmurr on Tuesday 7th October 12:44
paulmurr said:
Why not just buy an MX5 with a blower already installed?
Like this http://www.pistonheads.com/sales/697343.htm
ETA - not mine, just browsed over it
The whole thing about knockdown price really. I'm thinking its a great way into MX-5 ownership and then Like this http://www.pistonheads.com/sales/697343.htm
ETA - not mine, just browsed over it
Who knows, I may not get the thing anyway.
Loving the idea of the Alfa V6 in there though, mmmmmmm.
What about one of those twin Hayabusa engine V8 things, now that would be mental. 
The Mk2 1.6 is 115bhp. The 90bhp engine was only in the Mk1 from 94-98.
Personally I can't see the point of an engine swap unless it gives more than 250bhp easily and inexpensively and without forced induction as this is relatively easy to achieve with forced induction on the stock MX-5 engine, even the 1.6.
I know the guy with the 3.5L Rover block in his '5 but to be honest, while it sounds great it's still pretty slow only having about 150bhp. He could make changes to it to up the power to 200bhp or more but none of it is cheap and he's having enough trouble keeping it running as it is - especially as it's just a bit too tall so it's mounted a bit too low which means the sump has been cracked twice by speed-bumps. That's an engine-out job to fix it.
I asked before about the Alfa engine - it's a non starter but I can't remember why. Is it transverse? I also thought the MX3 1.8 V6 was transverse. Modding it so that it could run longitudinal would be expensive, especially considering it's only about 130bhp.
There are plenty of other engine options - the place to look is Miata.net. Pretty much anything that's doable has been done by someone over there.
You should always bear in mind though that an FM built 2L stroker costs about £5k and with forced induction can easily take you well beyond 300bhp.
Back to the original point though. I'd say buy it, drive it then decide what you want to do. Don't expect it to be a road-rocket, it won't even out-accelerate a 2.0 Mondeo but get it on a good twisty road, keep the revs above 5krpm and you'll have a massive grin on your face
Personally I can't see the point of an engine swap unless it gives more than 250bhp easily and inexpensively and without forced induction as this is relatively easy to achieve with forced induction on the stock MX-5 engine, even the 1.6.
I know the guy with the 3.5L Rover block in his '5 but to be honest, while it sounds great it's still pretty slow only having about 150bhp. He could make changes to it to up the power to 200bhp or more but none of it is cheap and he's having enough trouble keeping it running as it is - especially as it's just a bit too tall so it's mounted a bit too low which means the sump has been cracked twice by speed-bumps. That's an engine-out job to fix it.
I asked before about the Alfa engine - it's a non starter but I can't remember why. Is it transverse? I also thought the MX3 1.8 V6 was transverse. Modding it so that it could run longitudinal would be expensive, especially considering it's only about 130bhp.
There are plenty of other engine options - the place to look is Miata.net. Pretty much anything that's doable has been done by someone over there.
You should always bear in mind though that an FM built 2L stroker costs about £5k and with forced induction can easily take you well beyond 300bhp.
Back to the original point though. I'd say buy it, drive it then decide what you want to do. Don't expect it to be a road-rocket, it won't even out-accelerate a 2.0 Mondeo but get it on a good twisty road, keep the revs above 5krpm and you'll have a massive grin on your face
MX-5 Lazza said:
it won't even out-accelerate a 2.0 Mondeo but get it on a good twisty road, keep the revs above 5krpm and you'll have a massive grin on your face
The 1.6s aren't fast but they're not that slow 
I managed 9.1 to 60 with a G-Tech meter, and I reckon I can improve on that with dry ground and a harder launch. I'd expect it to easily keep up with a boggo 2L saloon.Twisty roads are where the fun is, though, yes
hcanning said:
I managed 9.1 to 60 with a G-Tech meter, and I reckon I can improve on that with dry ground and a harder launch.
So will a 2.0 Mondeo. And the Mondeo will have more torque so will be quicker in "real world" driving. With the MX-5 you have to thrash it to get the same speed - to me though that's part of the thrill.MX-5 Lazza said:
hcanning said:
I managed 9.1 to 60 with a G-Tech meter, and I reckon I can improve on that with dry ground and a harder launch.
So will a 2.0 Mondeo. And the Mondeo will have more torque so will be quicker in "real world" driving. With the MX-5 you have to thrash it to get the same speed - to me though that's part of the thrill.MX5: 116bhp, ~950kg = 124 bhp/ton
New Mondeo 2.0: 142bhp, 1477kg = 97bhp/ton
Mk2 (90's) mondeo 2.0: 128bhp, 1289kg = 100bhp/ton
So the MX5 has a higher power to weight ratio, and weight is a significant factor in acceleration, whether from a standstill or on the move. It'll certainly at least keep up with your average 2.0 family saloon IMHO, until the twisties. Then it'll be gone
I won't disagree the Mondeo is the better car for cruising and generally not hooning, though
Edited by hcanning on Wednesday 8th October 08:45
I've just been mulling this over whilst enjoying a break for a cup of tea. My thoughts are:
- A stock MX5 engine can be blown to anywhere up to 250bhp for the matter of about £3k or less worth of hardware
- Built engines can go significantly higher if you really wish.
- A stock MX5 engine can be bought for a few hundred pounds (up to around £500 for a Mk2) should the engine go pop
- The stock MX5 gearbox and (1.8) diff are fairly sturdy, 5 speed gearboxes being cheap to replace, Torsen diffs less so, but rarely seem to fail even with big power.
- Any MX5 engine from 1989 to 2004 can be fitted to any MX5 1989-2004 mechanically with just small electrical mods required (moderate mods if fitting a VVT engine to a non-VVT car).
- The best thing about the MX5 is it's balance and you'd want to be careful not to disturb this too much with an engine swap.
- The MX5 block is cast iron so an alloy blocked bigger engine might not be too weighty in comparison, but would it mount in the same place or would it push more weight further forward?
- Any engine other than an MX5 engine is going to need significant fabrication to get it to fit.
- The MX5 PPF is a brilliant piece of engineering and would likely be lost if using a different gearbox and/or diff.
does anyone know of any write ups of the fitting of an s14 engine into a 5? I have heard of a few, but my limited computer and internet skills fail me with results.
Thing is I could buy a cheap 5 needing some tlc (i can do all of that) plus have a mate tha can source me a decent sheap engine with all the gubbins and I can then do the conversion myself. Only thing is I would like to read a decent build thread to see what needs doing and getting etc
cheers folks
Thing is I could buy a cheap 5 needing some tlc (i can do all of that) plus have a mate tha can source me a decent sheap engine with all the gubbins and I can then do the conversion myself. Only thing is I would like to read a decent build thread to see what needs doing and getting etc
cheers folks
Hmm... I didn't expect this thread to get so much mileage, very interesting.
For me its a pipe dream really, one I'd love to do given the time and opportunity, and may well pursue later, but at the moment its purely theoretical.
A light motorcycle engine might be nice, but then I suppose you'd have the manic revving nature of a motorcycle engine, and you might lose some of the everyday nature of the MX-5, who knows?
Certainly not me, thats for sure.
Carry on.
For me its a pipe dream really, one I'd love to do given the time and opportunity, and may well pursue later, but at the moment its purely theoretical.
A light motorcycle engine might be nice, but then I suppose you'd have the manic revving nature of a motorcycle engine, and you might lose some of the everyday nature of the MX-5, who knows?
Certainly not me, thats for sure.
Carry on.
The problem with a motorbike engine is that while they do have fairly high power they have relatively low torque and an MX-5 is a fairly heavy thing compared to a Caterham/Westfield. That would mean revving it a lot to get it to go which would be fun for a while but it would soon get annoying.
Think the twin Hayabusa V8 engine is around £25k....
As for the ROver V8, I've never been much of a fan. In reality it's it's noise and lightness that are the good points (often rumoured to be lighter than many an 80's 4 pot at least), but power is generally overquoted in various tuning forms and parts are more expensive....
...step in the Yank V8's, the reason they sold the Buick V8 (Rover) to the UK was that they got the hang of thin wall casting, and so made their cast iron engines lighter than they were (not as light as the RV8 obviously) - difference is big power and torque is easily and cheaply available from these.
Some nutters put Yank V8's into MX%'s in teh states, think they are known as Monsters.
http://books.google.com/books?id=qCPR1QtIfHUC&...
As for the ROver V8, I've never been much of a fan. In reality it's it's noise and lightness that are the good points (often rumoured to be lighter than many an 80's 4 pot at least), but power is generally overquoted in various tuning forms and parts are more expensive....
...step in the Yank V8's, the reason they sold the Buick V8 (Rover) to the UK was that they got the hang of thin wall casting, and so made their cast iron engines lighter than they were (not as light as the RV8 obviously) - difference is big power and torque is easily and cheaply available from these.
Some nutters put Yank V8's into MX%'s in teh states, think they are known as Monsters.
http://books.google.com/books?id=qCPR1QtIfHUC&...
franv8 said:
Some nutters put Yank V8's into MX%'s in teh states, think they are known as Monsters.
MX-5 Lazza said:
As I understand it achieving more than 250 BHP reliably is pretty tough with a FI'd 1.8 engine.
As a regular browser of the miata.net engine swaps forum it seems an engine swap usually means changing the diff, gearbox and suspension, effectively meaning you are driving a car that isn't really an MX5 at all.
That said who wouldn't want one of these
http://uk.youtube.com/watch?v=nXmu_obZPcA (Chevy LS1 engined Mk2 driveby)
capable of this
http://uk.youtube.com/watch?v=ox7G3oG_PA8 (LS1 engined Mk1: 11.8 sec standing 1/4 @116mph)
As a regular browser of the miata.net engine swaps forum it seems an engine swap usually means changing the diff, gearbox and suspension, effectively meaning you are driving a car that isn't really an MX5 at all.
That said who wouldn't want one of these
http://uk.youtube.com/watch?v=nXmu_obZPcA (Chevy LS1 engined Mk2 driveby)
capable of this
http://uk.youtube.com/watch?v=ox7G3oG_PA8 (LS1 engined Mk1: 11.8 sec standing 1/4 @116mph)
zac510 said:
A rotary (Rx7 engine) is a great swap but they're not very common in the UK. Still cheap though.
would that be a turbo'drex engine on N/A?that sounds like a very interesting toy, do you know what other wokrk it takes to make it go other than droping in and plumbing up the engine?
sassthathoopie said:
As I understand it achieving more than 250 BHP reliably is pretty tough with a FI'd 1.8 engine.
Nah, a reliable 250bhp is pretty easy. I have 230bhp at the moment and I'm only running an cheap old eManage. I'll upgrade to eManage Ultimate/Megasquirt or Adaptronic when I can afford it, then I'll easily be able to get 250bhp and can go for 270bhp if I feel the need though I probably won't bother as 250bhp is plenty enough.Gassing Station | Mazda MX5/Roadster/Miata | Top of Page | What's New | My Stuff