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Discussion Starter #1
Probably at the risk of an immediate ban, was thinking about this today:)

I know it will be a load of work but if the yanks can get a V12 (youtube it:eek:) into one then the greatest V6 ever made should be OK.

Thinking MK1 MX5 so no issues with needing cats etc. Would use a later six speed MX5 gearbox, prop, slippy diff and shafts.

Will have to fabricate mounts and gearbox adaptor plate. I have access to CNC milling machine in the day job.

I am sure there is loads to go wrong, but thought it may prove an interesting discussion:confused:

I just so happen to have a nice 1990 Eunos parked on the drive:)
 

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If you can get it to fit then it should not be so bad :cheese:
Depending on the v12 the yanks used then there is a possibility that the v6 will be taller and thus make your life allot more difficult. As said you will need to fabricate mounts but you could possibly save yourself some issues by using a Alfa 75 rear mounted gear box “under/in the boot” this would probably handle the power better than the Mazda one and would also help the v6 sit closer to the engine bay firewall, could also possibly argue balance and the like but on this scale of brick in a sock I don’t think it matters.
I would defiantly subscribe to a build thread if you did start one as this is the sort of thing I like :thumbs:

Out of interest do you know the rough price that would be charged for a CNC’ed aluminium bell housing, I to have a **** plan :D
 

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Discussion Starter #3
If you can get it to fit then it should not be so bad :cheese:
Depending on the v12 the yanks used then there is a possibility that the v6 will be taller and thus make your life allot more difficult. As said you will need to fabricate mounts but you could possibly save yourself some issues by using a Alfa 75 rear mounted gear box “under/in the boot” this would probably handle the power better than the Mazda one and would also help the v6 sit closer to the engine bay firewall, could also possibly argue balance and the like but on this scale of brick in a sock I don’t think it matters.
I would defiantly subscribe to a build thread if you did start one as this is the sort of thing I like :thumbs:

Out of interest do you know the rough price that would be charged for a CNC’ed aluminium bell housing, I to have a **** plan :D
Cheers for the support, wasn't sure the reaction I would get:confused:

Can anybody point me to the dimensions of the 3.0 or 3.2 engine please?

I was also thinking that I may need the 75 sump as well?

Not sure on the cost of a machined bellhousing, would you just need an adaptor plate making up?
 

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I would say in general on here you would have over 2/3rds in favour of a good build project, roughly 1/3rd who could not see the point, and in total a 6th that would anger at the very thought of anything Alfa being placed in the same proximity as something non-Alfa. As long as you keep to the technical Engines and Tuning lounge I’m sure you will be fine!

If I was looking for a donor for your project I would look for an old 75 “one with a shell that is in poor condition so not to annoy Alfisti” that should have all the bits you need to get going.

For my project I am still trying to figure out the best way to reach my goals, ether complete custom bell housing or a sodomized standard FWD gearbox/bell housing cutting off the gearbox and fitting an adapter plate ether way will probably need roller bearings pressed. Would also need an adapter plate for the gearbox to torque tube.

If you are looking at using the 12V engine and a 75 as a basis I would strongly recommend buying the following book “Alfa Romeo V6 Engine - High Performance Manual” amazon do it for £17 and will help answer most if not all your questions.

Good luck with your project and please keep us updated

J
 
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I'm sure you have already thought about this: but the MX5 is one of the best handling cars ever, why disturb the balance?

Have you not thought about a 3.0 twin turbo supra lump?
Turbopacs in Durham do an MR2 to Supra conversion and thats a really tight engine bay. I can see your method in the madness as it truly is the best V6 ever IMO on an Alfa but bang for your bucks you would be better off going a different route... Good luck anyway
 

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Discussion Starter #6
I'm sure you have already thought about this: but the MX5 is one of the best handling cars ever, why disturb the balance?

Have you not thought about a 3.0 twin turbo supra lump?
Turbopacs in Durham do an MR2 to Supra conversion and thats a really tight engine bay. I can see your method in the madness as it truly is the best V6 ever IMO on an Alfa but bang for your bucks you would be better off going a different route... Good luck anyway
I cant say I am looking for massive bhp, if a 3.2 V6 came along at the right price I think 250bhp in my MX5 would be "adequate"!:D

Handling wise the V6 should sit a little further back than the current 4 which should offset the gain in weight. Removing all the AC gubbins will also help in the weight saving department

I think it will be tight on the height, I read on here that the engine is 680mm bottom of sump to top, I assume the induction pipes?? A number of people who have put the 2.5 Mazda engine in have used TB but I am hoping to be able to keep the visual effect of the pipes:thumbs:

Anyway, getting an MX5 subframe to butcher at the weekend, and will be measuring up a six speed MX5 gearbox for an adapter plate. I just need to find a cheap broken V6 to use as a test bed for the trial fitting:D
 

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The 75 has a sump with the cooling fins running longitudinally when the v6 donkey is driving the rear wheels. It probably has a baffle in it too, to keep the oil from running to the back when you accelerate... so if you don't have a 75 engine, you should still try to get hold of the sump.

If the engine is a bit too tall for the Mazda bonnet... cut a hole in the bonnet! :)

Ralf S.
 

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The 75 has a sump with the cooling fins running longitudinally when the v6 donkey is driving the rear wheels. It probably has a baffle in it too, to keep the oil from running to the back when you accelerate... so if you don't have a 75 engine, you should still try to get hold of the sump.

If the engine is a bit too tall for the Mazda bonnet... cut a hole in the bonnet! :)

Ralf S.
I'm getting a MADMAX vibe from that idea

and i'm like'ing it
 

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Discussion Starter #9
I'm getting a MADMAX vibe from that idea

and i'm like'ing it
:D

Another question, the Plenum will not fit as the TB will be up against the MX bulkhead.

I was wondering if anybody has mounted the plenum on the other side of the engine by rotating the inlet tubes 180Deg with the TB at the front of the engine?
 

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i think someone has mounted the plenum on the other side, i think it was on another post on here where a guy was building a turbo powered v6 for a lancia stratos, cant remember where this was though sorry!
 

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Discussion Starter #11
i think someone has mounted the plenum on the other side, i think it was on another post on here where a guy was building a turbo powered v6 for a lancia stratos, cant remember where this was though sorry!

Thanks, I did try a search but no luck, would be good to see some pictures:D
 

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i think someone has mounted the plenum on the other side, i think it was on another post on here where a guy was building a turbo powered v6 for a lancia stratos, cant remember where this was though sorry!
Yes, he's om here. Username turbonutter. There are a couple of build pics in the tuning section, but if you Google busso+stratos+turbo you'll find a much more detailed build thread on another forum.

These kind of builds are of course never sensible. But they turn me on anyway, so lots of pics when you get started pls :)

Edit: and yes, he's moved the plenum to the other head.
 

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Discussion Starter #13
Yes, he's om here. Username turbonutter. There are a couple of build pics in the tuning section, but if you Google busso+stratos+turbo you'll find a much more detailed build thread on another forum.

These kind of builds are of course never sensible. But they turn me on anyway, so lots of pics when you get started pls :)

Edit: and yes, he's moved the plenum to the other head.
Many thanks, at least I can see it has been done before, getting quite excited about this now, my only concern is the height of the engine?

Can anybody confirm 680mm bottom of sump to top of plenum:confused:

Thanks:thumbs:
 
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Giving my Nella a wash today, I'll lift the bonnet and measure sump to plenum top as best I can for you ok mate:thumbs:

P.s. There is no reason why you can't swap the plenum 180 degrees, the only issues is breather pipes which will need repositioning
 

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Discussion Starter #15
Giving my Nella a wash today, I'll lift the bonnet and measure sump to plenum top as best I can for you ok mate:thumbs:

P.s. There is no reason why you can't swap the plenum 180 degrees, the only issues is breather pipes which will need repositioning
Any luck with that measurement?

Thanks:thumbs:
 

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Given the level of fabrication etc you are looking at, then the plenum is the least of your worries I'd think - no big deal to replicate the 75 arrangement with inlet runners coming upwards and a central plenum, assuming you have the bonnet clearance. Failing that, as mentioned, swinging the plenum to the other bank is quite do-able as well.

FWIW, I'd avoid 12V motors and early 24V ones. Go for the latest 24V you can find, ideally a 3.2 if you can find one. The 166 is a good donor for a 3.0. GTA 147/156 for the 3.2 as there are more of them about.

Before everyone gets all irate about that, I built a couple of 12V motors a while back but parts are getting scarce and you can't argue with the results form the later 24V motors.

A stock 3.2 on a decent exhaust and aftermarket management will make 280bhp if memory serves.

Neat project by the way, but as mentioned, beware the weight of the Busso engine - it might be aluminium but light it aint. I really noticed the weight/CG difference in my Strat copy when I changed from a Lancia twin cam to a 12V V6.


(eta...really must change my avatar - sold that car last year)
 

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i have to say although i love the alfa v6 if i were changing a engine in an mx5 i would go for a rotary engine, it would make the mx5 a formidable track weapon and as it has been done before there will be more experience from others on how to( helps keep the cost down)

Saying that i would still love to put an alfa v6 in my old capri and spaceframe it, have a few turbos attached with a proper zakspeed bodykit, it would sound and drive and look like a beast :) (waiting on lottery win lol)
 
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