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Engine choice !
Aleksandar - 21/5/19 at 12:16 PM

Hello all,

My name is Aleks and I have decided to get an MK Indy RR chassis. Order to be placed with Sean later this year.

I am currently planning and smashing my head against the keyboard in trying to understand all the items that go with the kit.

Torn between 3 engine choices and I would like some advice.

I will start by saying that I have decided to use MX5 gearbox and do not want to use a ford type 9. Personal preference really.

The car will be used for weekend drives but track days as well, I am hoping to get 6-8 track days a year.

Engine wise I am looking at doing ( Throttle bodies/ management , port and polish by a mate and refresh the bottom end if needed and at a later stage: cams) My ideal goal would be to hit 180hp -190hp with no cams.

Option 1 : 1.8vvt Mazda engine 143 Hp.

This would be easier as it is the engine that does not need much mods to use as RWD because it came from MX5 but I don't know if it will hit the power figure that I have in my mind. Throttle bodies are not as common as for Zetec/Duratec

Option 2 : 2.0 Zetec ford engine black top 143 hp ( if I am not wrong).

What are the advantages over the Mazda unit as it seems that there is going to be a slight increase in torque but will it be more powerful using the setup mentioned above and is it worth using this engine.

It will need alterations to use in RWD setup if I understand correctly ( Sump, Relocation kit for water, adaptor plate for mx5 gearbox , this is all the items I have found, please confirm if there is more items needed) .

Option 3 : 2.0 Duratec ( ford/mazda unit ) 150hp / 160 hp

Advantage of this setup would be that apparently this bolts to the Mazda gearbox with no adaptor plate but I am yet to confirm that I can fit this in the MK Indy RR chassis ( presuming it has been done before ) . If using the ford engine it will still need a sump.

Produces more power with throttle bodies and should be easier to get to 190hp then the above two engines.

Price wise the Mazda Duratec is almost double or triple the money then the rest of the engines so this needs to be taken into consideration as well.

I am tempted to go with the standard 1.8 Mazda engine because its should be easier cheaper but I do want to hit the Hp numbers stated above and I am not sure if this engine will be capable.

I have spoken to Dunnell and they have offered a 2.0 zetec ( 192hp ) with running in and crate engine ready for MX5 gearbox for 5500 plus VAT but at this point I am a bit shocked about the price and would like to put a cost down for a second hand option and see how much less that would be.


Would appreciate any help , input or opinions.

Regards,
Aleks


Ugg10 - 21/5/19 at 01:19 PM

Couple of things to bear in mind -

The Zetec is not an easy fit on the Mazda gearbox (you thinking 5 speed or 6 speed), an easier fit us the rx8 box as it has the same input shaft splines as the ford clutches (23 spline 1 diam). The 6 speed box is an AZ6 by Austin and is used in the mk3 NC mx5 but with a different bellhousing bolt pattern. Zetec rx8 conversion plates are readily available.

The Duratec needs the mk3 NC mx5 box to just bolt on, however the engine sits at an angle so you need to check if this still fits under the bonnet and clears any rails.

If you do the Zetec route worth looking at a st170, badged a Duratec but it is a Zetec block, you can use the ford ecu by following the info on here on how to get it running. Cheapest power available imo, up and running for 500 plus exhaust manifold.


big_wasa - 21/5/19 at 02:08 PM

Retro Ford do some nice parts to bolt the mk3 Mazda box to a zetec.

I love a zetec, easy to work on and power is proportional to money and skills.

But there are newer engines out there.
If I was starting again I would be looking at future proofing. I would be thinking about emissions and possible tax bracket changes.

I would be looking at the Ford 1.6 ecoboost. What you spend on the ecu you will save on throttle bodies.


miskit - 21/5/19 at 02:54 PM

Make life easy with the Mazda 1.8VVT - bolt on a Supercharger or Turbo with an ME221 (or similar) controller- been done lots.

[Edited on 21/5/19 by miskit]


Simon - 21/5/19 at 04:35 PM

As said, turbo the Mazda unit and make life easier for yourself. Get it on the road then faff around with it.


Partofthechaos - 22/5/19 at 07:52 AM

As said by others, the MX5 engine has to be the one to go for. It has minimal differences to the other engines, but will be a lot easier.

Regarding adapter plates, the similarity of the engines means that this is not going to be something which has been done much, so you may be commisioning one from scratch. This will be more expensive and has the oportunity for niggles long term.

Regarding the engine to chassis compatability, I'm not too sure about the Indy RR, but the Indy RX5 is based on the MX5 as a donor. If the RR is still based on Ford bits, I'm sure MK can adapt this during fabrication. Assuming this is correct, the MX5 engine will drop straight into the chassis. Nothing custom will make everything a lot easier.

If 143bhp isnt enough, add a turbo or supercharger. The Indy RX5 is setup to accept turbos so shouldnt be an issue.


Paul_Arion - 22/5/19 at 08:00 AM

DanST does a bolt on throttle bodies and ECU kit for the MX5 VVT engine

DanST


Aleksandar - 22/5/19 at 12:21 PM

I have spoken to Sean at MK and as far as I understand you can use the RR chassis with MX5 donor parts and use zetec/bike engine or mazda engine.

I would prefer to stay naturally aspirated for more than one reason as I think it has a beautiful sound and maintenance is very easy in comparison to turbo or supercharger, no overheating on track, no turbos to blow etc.

The mx5 would be easier to get in and get some throttle bodies on there but it is not as cost effective as a zetec once you look at the hp per pound.

Best hp per would be the st170 engine as this tunes easy to 190-200hp but will this bolt on to the mx5 with retro ford adaptor plate?

Is it heavier than the usual zetec by much?

Aleks


big_wasa - 22/5/19 at 01:32 PM

The Retro Ford parts are for the mk3 box. But the 5spd N7 box is still fairly cheap.

No body commercially produces an adapter for the mk1~2.5 box but I know a guy has produced a few for his own use and even drags it so it must be fairly robust.

I would say any weight differance between a Blacktop and an St170 is negligible.



[Edited on 22/5/19 by big_wasa]


JimSpencer - 22/5/19 at 02:00 PM

quote:
Originally posted by Aleksandar
I have spoken to Sean at MK and as far as I understand you can use the RR chassis with MX5 donor parts and use zetec/bike engine or mazda engine.

I would prefer to stay naturally aspirated for more than one reason as I think it has a beautiful sound and maintenance is very easy in comparison to turbo or supercharger, no overheating on track, no turbos to blow etc.

The mx5 would be easier to get in and get some throttle bodies on there but it is not as cost effective as a zetec once you look at the hp per pound.

Best hp per would be the st170 engine as this tunes easy to 190-200hp but will this bolt on to the mx5 with retro ford adaptor plate?

Is it heavier than the usual zetec by much?

Aleks



You're way overcomplicating this.. don't worry about the power, anything circa 150ish and up will be staggeringly quick,

Make the build process as easy as you can, stick with as many of the Mx5 bits as you can, add throttle bodies etc if you wish, but keep the build simple then, one winter, upgrade it - once you know you need that extra power
You certainly won't for a good year or two and you certainly won't for trackdays, a MX5 powered Seven, that's properly set up will be as quick round any track as any other road car you're likely to come across..

I run the Striker in my photo gallery on the odd trackday, it's 1600cc normally aspirated, can't recall being overtaken by much with number plates..


HowardB - 22/5/19 at 03:00 PM

quote:
Originally posted by big_wasa
The Retro Ford parts are for the mk3 box. But the 5spd N7 box is still fairly cheap.

No body commercially produces an adapter for the mk1~2.5 box but I know a guy has produced a few for his own use and even drags it so it must be fairly robust.

I would say any weight differance between a Blacktop and an St170 is negligible.



[Edited on 22/5/19 by big_wasa]


Model A drag racing a Landy - interesting!


big_wasa - 22/5/19 at 05:34 PM

He has some other interesting projects as well.


G13BLocost - 22/5/19 at 07:26 PM

quote:
Originally posted by JimSpencer
quote:
Originally posted by Aleksandar
I have spoken to Sean at MK and as far as I understand you can use the RR chassis with MX5 donor parts and use zetec/bike engine or mazda engine.

I would prefer to stay naturally aspirated for more than one reason as I think it has a beautiful sound and maintenance is very easy in comparison to turbo or supercharger, no overheating on track, no turbos to blow etc.

The mx5 would be easier to get in and get some throttle bodies on there but it is not as cost effective as a zetec once you look at the hp per pound.

Best hp per would be the st170 engine as this tunes easy to 190-200hp but will this bolt on to the mx5 with retro ford adaptor plate?

Is it heavier than the usual zetec by much?

Aleks



You're way overcomplicating this.. don't worry about the power, anything circa 150ish and up will be staggeringly quick,

Make the build process as easy as you can, stick with as many of the Mx5 bits as you can, add throttle bodies etc if you wish, but keep the build simple then, one winter, upgrade it - once you know you need that extra power
You certainly won't for a good year or two and you certainly won't for trackdays, a MX5 powered Seven, that's properly set up will be as quick round any track as any other road car you're likely to come across..

I run the Striker in my photo gallery on the odd trackday, it's 1600cc normally aspirated, can't recall being overtaken by much with number plates..


This.


Aleksandar - 23/5/19 at 12:45 PM

quote:
Originally posted by G13BLocost
quote:
Originally posted by JimSpencer
quote:
Originally posted by Aleksandar
I have spoken to Sean at MK and as far as I understand you can use the RR chassis with MX5 donor parts and use zetec/bike engine or mazda engine.

I would prefer to stay naturally aspirated for more than one reason as I think it has a beautiful sound and maintenance is very easy in comparison to turbo or supercharger, no overheating on track, no turbos to blow etc.

The mx5 would be easier to get in and get some throttle bodies on there but it is not as cost effective as a zetec once you look at the hp per pound.

Best hp per would be the st170 engine as this tunes easy to 190-200hp but will this bolt on to the mx5 with retro ford adaptor plate?

Is it heavier than the usual zetec by much?

Aleks



You're way overcomplicating this.. don't worry about the power, anything circa 150ish and up will be staggeringly quick,

Make the build process as easy as you can, stick with as many of the Mx5 bits as you can, add throttle bodies etc if you wish, but keep the build simple then, one winter, upgrade it - once you know you need that extra power
You certainly won't for a good year or two and you certainly won't for trackdays, a MX5 powered Seven, that's properly set up will be as quick round any track as any other road car you're likely to come across..

I run the Striker in my photo gallery on the odd trackday, it's 1600cc normally aspirated, can't recall being overtaken by much with number plates..


This.


Thank you for your words of advice... I have taken that in and will definitely take it on-board.

Throttle bodies and head work on an MX5 engine with VVT should get me where I want to be and getting a donor and having most of the things needed will simplify the job as you have said.

Can someone guide me to a company that would be able to offer cylinder head porting in south Uk.

I would ask my mate to do it as he has done previously on bmw cylinder heads but would like to see what the cost is to get this done professionally.

Jenvey is my pick at the moment as they look better than bike carbs and seem to have a good reputation with ME221 software if that can control the VVT as well and then get it mapped .