Mazda RX8 project with 20v Audi turbo engine
07-12-2011, 06:11 PM
#1
Mazda RX8 project with 20v Audi turbo engine
The wife has always fancied an RX8, they're a decent car but have huge problems with failing engines and high oil and fuel consumption so I bought her a BMW Mini convertible instead.. Anyhow I noticed that people are now practically giving away RX8's once the engine has failed so I bought one with an expired engine and decided to fit an Audi 20v and the wife can have it to use when she's not using the Mini (cold weather isn't great with a convertible). Anyhow £900 got me this..
Two owners from new and only 56k miles
Engine out and bulkhead chopped
Audi in place and engine mounts being made
I'm using the RX8 gearbox with an adaptor plate and custom flywheel, I'm a bit sad now because I have found another one that's even nicer condition and has a 6 speed box (rather than a 5 speed like the silver car) and its a nicer colour too..
So I had to buy it!! I have measured it up and a YB will fit in
Two owners from new and only 56k miles
Engine out and bulkhead chopped
Audi in place and engine mounts being made
I'm using the RX8 gearbox with an adaptor plate and custom flywheel, I'm a bit sad now because I have found another one that's even nicer condition and has a 6 speed box (rather than a 5 speed like the silver car) and its a nicer colour too..
So I had to buy it!! I have measured it up and a YB will fit in
Last edited by Martin-Hadland; 07-12-2011 at 06:18 PM.
RX8's are quite high spec when you have a good look.. All alloy adjustable suspension arms and a carbon prop 
07-12-2011, 07:49 PM
#17
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Strange, I was watching a couple on the bay for the past week with the intention of using my spare evo engine, albeit with a toyota R154 gearbox!
Excellent shout on the 20V if the gearbox is man enough. Should be a great bit of kit Mart!
Excellent shout on the 20V if the gearbox is man enough. Should be a great bit of kit Mart!
07-12-2011, 09:52 PM
#24
Would the Evo lump work with the RX8 box then Martin do you reckon?
I've got a spare 4G63 motor here (well actually got the whole car), and always liked the RX8s, be nice to mix the two together into a good looking nicely specced fast RWD car
My Evo 6 in it's current state (was planning something else, but like this RX8 idea):
I've got a spare 4G63 motor here (well actually got the whole car), and always liked the RX8s, be nice to mix the two together into a good looking nicely specced fast RWD car
My Evo 6 in it's current state (was planning something else, but like this RX8 idea):
08-12-2011, 06:22 AM
#27
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Would the Evo lump work with the RX8 box then Martin do you reckon?
I've got a spare 4G63 motor here (well actually got the whole car), and always liked the RX8s, be nice to mix the two together into a good looking nicely specced fast RWD car
My Evo 6 in it's current state (was planning something else, but like this RX8 idea):
I've got a spare 4G63 motor here (well actually got the whole car), and always liked the RX8s, be nice to mix the two together into a good looking nicely specced fast RWD car
My Evo 6 in it's current state (was planning something else, but like this RX8 idea):
08-12-2011, 07:35 AM
#28
The original engine is about the height of a normal 4 pot with the head removed, so the trans tunnel/bulkhead wasn't designed to clear anything above that height and also the belhousing actually sits inside of the tunnel so you can see that although a spacer plate would bring everything forward its still not enough if the head has anything overhanging further than the block face. The Audi engine has 4" of stuff protruding
I have reduced this to 2" with a bit of relocation. So in an ideal world the gearbox would need to be moved forwards...Problemo No.2 The gearbox doesnt have a conventional mount and crossmember, it has a long steel 'power frame' that joins the diff to the gearbox so no box crossmember (it does have a carbon prop though
). The gear stick goes straight into the box so the box can't be moved forward as the dash is in the way.Sitting the engine further back does have its advantages though, the original electric power steering rack can be retained as the Audi pulley clears it and the other bonus is the engine sits behind the centreline of the front wheels
So in short if you're considering this you need and engine that doesn't have more than 2" head protrusion at the rear or you need to change the box and make mounts for that and the rear diff.
08-12-2011, 01:04 PM
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The problem with rotarys in the uk is that hardly anyone knows anything about them.
Every one assums that they cant run big boost. when really is the mapper
being far to aggressive.
Due to there design they can spool huge turbos easily.
People use these big turbos as instead of running more boost.
That is why in the uk there are loads of rx7s running t88,gt35,hks t51r ect ect and only ruuning 0.9 bar of boost.
This is the reason they feel gutless, It dosent matter how big your turbo is.
Boost=torque
lack of boost= no torque.
This is why uk rx7s feel gutless.
The solution to this problem ?
PRE-compressor water injection.
I know of one rx7 running this in the uk with 1.7bar
His first comments was about how torquey it felt, and how hard it pulled.
There is also loads is cars in australia running this.
IMO a 1.8 vag engine is a step backwards, but cool all the same
What I would do is 2.6 bridge ported quad rotor engine, with a huge twin scroll turbo (possibly running a quick spool valve) and a vast amount of pre comp water injection.
Would make a very fast car.
Last edited by Fiesta_Jed; 08-12-2011 at 01:06 PM.
08-12-2011, 01:51 PM
#35
the engine is not "shit"
Engine dosent let them down, Its the people that dont know anything about them that do.
See below
There actually a far better concept in terms of performance than a piston engine.
The problem with rotarys in the uk is that hardly anyone knows anything about them.
Every one assums that they cant run big boost. when really is the mapper
being far to aggressive.
Due to there design they can spool huge turbos easily.
People use these big turbos as instead of running more boost.
That is why in the uk there are loads of rx7s running t88,gt35,hks t51r ect ect and only ruuning 0.9 bar of boost.
This is the reason they feel gutless, It dosent matter how big your turbo is.
Boost=torque
lack of boost= no torque.
This is why uk rx7s feel gutless.
The solution to this problem ?
PRE-compressor water injection.
I know of one rx7 running this in the uk with 1.7bar
His first comments was about how torquey it felt, and how hard it pulled.
There is also loads is cars in australia running this.
IMO a 1.8 vag engine is a step backwards, but cool all the same
What I would do is 2.6 bridge ported quad rotor engine, with a huge twin scroll turbo (possibly running a quick spool valve) and a vast amount of pre comp water injection.
Would make a very fast car.
Engine dosent let them down, Its the people that dont know anything about them that do.
See below
There actually a far better concept in terms of performance than a piston engine.
The problem with rotarys in the uk is that hardly anyone knows anything about them.
Every one assums that they cant run big boost. when really is the mapper
being far to aggressive.
Due to there design they can spool huge turbos easily.
People use these big turbos as instead of running more boost.
That is why in the uk there are loads of rx7s running t88,gt35,hks t51r ect ect and only ruuning 0.9 bar of boost.
This is the reason they feel gutless, It dosent matter how big your turbo is.
Boost=torque
lack of boost= no torque.
This is why uk rx7s feel gutless.
The solution to this problem ?
PRE-compressor water injection.
I know of one rx7 running this in the uk with 1.7bar
His first comments was about how torquey it felt, and how hard it pulled.
There is also loads is cars in australia running this.
IMO a 1.8 vag engine is a step backwards, but cool all the same
What I would do is 2.6 bridge ported quad rotor engine, with a huge twin scroll turbo (possibly running a quick spool valve) and a vast amount of pre comp water injection.
Would make a very fast car.
As far as a step backwards fitting a 20v turbo, just look how many cheap VAG 20v turbo equiped cars are for sale cheap because the engine has expired and then compare to RX8
Truth is the RX8 is a good car that most folk are shit scared of incase they become a victim!All IMHO of coarse
08-12-2011, 02:14 PM
#38
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Martin you are a fucking ledgend i'd love to meet you one day, Seriously very interested in this always liked the rx8 but never had one due to the obvious WANK issue lol will be watching this closely,
On another note please please finish the mondeo!!!!
On another note please please finish the mondeo!!!!
08-12-2011, 02:19 PM
#39
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Sorry I disagree with you, I reckon they're rubbish for what 90% of people want! High fuel consumption, high oil consumption oh and one other component thats missing.... A turbo!! Why are you mentioning turbo's when they don't have them as std??
As far as a step backwards fitting a 20v turbo, just look how many cheap VAG 20v turbo equiped cars are for sale cheap because the engine has expired and then compare to RX8 Truth is the RX8 is a good car that most folk are shit scared of incase they become a victim!
All IMHO of coarse
As far as a step backwards fitting a 20v turbo, just look how many cheap VAG 20v turbo equiped cars are for sale cheap because the engine has expired and then compare to RX8
Truth is the RX8 is a good car that most folk are shit scared of incase they become a victim!All IMHO of coarse
As for the high oil and fuel consumption, thats a fair point. Cant argue with that.
When I said step backwards i meant as a design concept, IMO the rotary is hard beat
Your right though, they arent very reliable (through no fault of there own)
For what I assume you are trying to achive (a reliable, semi economical, fast road car that has plenty spare parts) You couldnt have picked a better engine
I will be watching your thread with interest
Last edited by Fiesta_Jed; 08-12-2011 at 02:21 PM.
08-12-2011, 02:25 PM
#40
I was talking about FD rx7`s which do have tubo's , sorry for any confusion.
As for the high oil and fuel consumption, thats a fair point. Cant argue with that.
When I said step backwards i meant as a design concept, IMO the rotary is hard beat
Your right though, they arent very reliable (through no fault of there own)
For what I assume you are trying to achive (a reliable, semi economical, fast road car that has plenty spare parts) You couldnt have picked a better engine
I will be watching your thread with intrest
As for the high oil and fuel consumption, thats a fair point. Cant argue with that.
When I said step backwards i meant as a design concept, IMO the rotary is hard beat
Your right though, they arent very reliable (through no fault of there own)
For what I assume you are trying to achive (a reliable, semi economical, fast road car that has plenty spare parts) You couldnt have picked a better engine
I will be watching your thread with intrest
All good.