mx-5 donor 1.8 or 1.6??

[CTWV50]

Hello all newbie here.

Looking to use a mazda as a donor but can't decide if the 1.6 engine has a good weight saving over the 1.8 which only has a 15bhp advantage. Obiously it will have more torque through out the rev range but.....

Any ideas anyone? Anyone know the weight advantage?

[Airhead]

Personally speaking I went for the 1.6 vspec as you just don't need the torque IMHO but I am sure others will have differing opinions.

Matt

[CTWV50]

Yeah I think your right seems there's really not much between these engines 10lbft and 10bhp isn't going to make much difference? Is there a weight advantage though? I suppose the reciprical rotational weight will make a difference (lighterflywheel and crank etc). What's the vspec sorry?

[Airhead]

V-spec stands for v-special. Basically the same car but with uprated suspension and LSD. The interior is also different (tan leather with high back seats) and they generally came in BRG but a few were sold in a high gloss black.

I found this engine comparison:

1.6 or 1.8?
I probably get asked about this more than any other aspect of an MX5 purchase. Lets look at the facts: when new, the 1.6 was good for 114bhp while the 1.8 produced 130bhp, an increase of 15% and had around 10% more torque produced lower down the rev range. However the 1.8 is a little heavier (50-70kg depending on exact model) so performance is not so different – an extra couple of mph on top speed and a couple of tenths of a second quicker to 60mph. Remember all these figures apply to nice shiny new cars: time and useage will have played a big part in how they drive now. In reality, a 1.8 has a little more low down power and seems to cope with motorway cruising a little more easily than a 1.6 but I reckon most people wouldn’t notice the difference. The 1.6 is a sweeter revving engine and a few well chosen modifications will significantly boost bhp and driving fun. In fact the 1.6 cars are the default choice for enthusiasts wishing to undertake serious tuning – fitting either super or turbochargers for example.
The real world answer is forget the engine and just concentrate on finding the nicest car you can. The exception to this is the late model UK 1.6 introduced in 1995: this was detuned to around 88bhp and is noticeably slower than the early 1.6 cars.

[AshG]

my mx5 i used for the exocet is a 1.8 it had a fair bit more poke than the 1600's i test drove

[CTWV50]

Originally Posted by Airhead

V-spec stands for v-special. Basically the same car but with uprated suspension and LSD. The interior is also different (tan leather with high back seats) and they generally came in BRG but a few were sold in a high gloss black.

I found this engine comparison:

1.6 or 1.8?
I probably get asked about this more than any other aspect of an MX5 purchase. Lets look at the facts: when new, the 1.6 was good for 114bhp while the 1.8 produced 130bhp, an increase of 15% and had around 10% more torque produced lower down the rev range. However the 1.8 is a little heavier (50-70kg depending on exact model) so performance is not so different – an extra couple of mph on top speed and a couple of tenths of a second quicker to 60mph. Remember all these figures apply to nice shiny new cars: time and useage will have played a big part in how they drive now. In reality, a 1.8 has a little more low down power and seems to cope with motorway cruising a little more easily than a 1.6 but I reckon most people wouldn’t notice the difference. The 1.6 is a sweeter revving engine and a few well chosen modifications will significantly boost bhp and driving fun. In fact the 1.6 cars are the default choice for enthusiasts wishing to undertake serious tuning – fitting either super or turbochargers for example.
The real world answer is forget the engine and just concentrate on finding the nicest car you can. The exception to this is the late model UK 1.6 introduced in 1995: this was detuned to around 88bhp and is noticeably slower than the early 1.6 cars.

Good bit of info that! LSD! 50kg! I'm sold thank you so much. Do you have plans for your chassis? how does your design vary from what Saturn are putting together?

[Airhead]

My build has taken a little longer to do as I started mine last March so I have had to start from scratch. Generally they will be very similar. My rears are adjustable and the shock mounts low, also my diff sits much lower (25mm by eye) but apart from that I can't see a massive difference in the designs although I think comparing the geometry would show some differences.

I will be starting production of the wishbones in conjunction with some local companies soon as well as part built chassis kits and donor packages but I will be concentrating exclusively on the MX5 as it is what I know and love.

I recently acquired the most exciting bit for my build, a shiney new turbo! A little bit outside my comfort zone but the beauty of living in Cornwall is that there are plenty of retired enthusiasts with a lifetime of knowledge and time to help

I will go with that, Cornwall is a cracking place to live...
I like that beach near St Keverne called a "car park"!! you could actually just keep going and drive straight into the sea...

[Airhead]

Originally Posted by fabbyglass

I will go with that, Cornwall is a cracking place to live...
I like that beach near St Keverne called a "car park"!! you could actually just keep going and drive straight into the sea...

That'll be Porthallow and/or Porthoustock then. Apparently it is a regular spectator event watching the poor fools who have got too close waiting to see if the tractor driver is going to reach them before the incoming tide!

(oops thread hijack - sorry )

Matt

[CTWV50]

Originally Posted by Airhead

My build has taken a little longer to do as I started mine last March so I have had to start from scratch. Generally they will be very similar. My rears are adjustable and the shock mounts low, also my diff sits much lower (25mm by eye) but apart from that I can't see a massive difference in the designs although I think comparing the geometry would show some differences.

I will be starting production of the wishbones in conjunction with some local companies soon as well as part built chassis kits and donor packages but I will be concentrating exclusively on the MX5 as it is what I know and love.

I recently acquired the most exciting bit for my build, a shiney new turbo! A little bit outside my comfort zone but the beauty of living in Cornwall is that there are plenty of retired enthusiasts with a lifetime of knowledge and time to help

I see, once I have my donor and commited myself as it were I will need to get some steel, can't decide if I want to go precut or cut the steel as I need it. Can't see myself making the wishbones though. Yep a turbo is on my my future list but may just have a play with a bit of NOS just for fun and the quarter mile. What other mechanical parts do you need other than the mazda donor? Do you still need to use an escort rack?