MX5 Builders - Group Buy

[PorkChop]

This thread is to see if any of the MX5 builders would be interested in joining in on a group buy for a coolant reroute spacer. I have spoken to the chap running the GB and he was happy for me to mention it on here. If the mods on this forum have any problem with me posting this GB, please feel free to get in touch/moderate the thread.

The MX5 engine has its coolant inlet and outlet on the front of the engine block/head, which results in relatively poor cooling of cylinders 3 and 4, dropping system efficiency. You can get coolant reroute kits from MX5 tuners (e.g. http://www.flyinmiata.com/index.php?...0%20%201990-93 ). As the coolant system on a Roadster can be tightly confined, improving the cooling efficiency would be a good thing IMO, especially if doing track day work, or if you have (or planning to have) a charged/tuned MX5 lump.

There is a group buy on MX5Nutz at the moment for the rear spacer needed for the foundation of a reroute kit. The best way for me to explain it (and what else would be required in addition to this spacer) is to put this link in - http://www.mx5nutz.com/forum/index.php?showtopic=89997

Please note that extra parts and work will be required in addition to this spacer to have a complete reroute. It's suitable for mark 1 1.6 and 1.8 lumps, and mark 2 engines with extra modification.

Estimated cost ATM is approx £65 each, but is likely to decrease if 20 people sign up (I think there's 11 ATM). The GB thread is here - http://www.mx5nutz.com/forum/index.php?showtopic=99220

The GB thread link also contains insights from MX5 owners on these spacers after they were fitted.

Just thought it might be handy for some on here - the chap has done this GB before, but reckons that this will be the last one.

Cheers

[Johno]

Good find,
Didn't know about MX5's having a cooling issue.....
Will it create any clearance issues that you know of with the chassis etc....
I wiil talk to my "Financial Advisor"....hhhhhmmmmm and see what she says.
Any ideas of the complete cost?

Cheers Johno

[PorkChop]

It's not a problem per se, I daresay a standard lump in a MX5 would be happy with the OEM routing (my standard MX5 has covered over 160K miles with the OEM set-up, so it can't be that bad). Mazda did, apparently, make some changes to the coolant set-up on later models of the MX5.

Clearance issues...the spacer itself appears to fit MX5s with no bulkhead modifications (although there's not a lot of space), so as long as there's at least as much space in a Roadster, I can't see that being an insurmountable problem. The only other possible sticking point I can think of ATM is routing the coolant back to the front of the car. Most MX5 owners seem to route it under the inlet manifold but it's a rather busy area for a Roadster, so the coolant route might need some thinking about. It's impossible to say for sure until it's all offered up in situ.

Costs...the threads on MX5Nutz I linked in the OP should tell you all you need to know when it comes to buying the extra parts to fit the spacer to the MX5. Of course, things will be different in the Roadster, so more tubing or extra clips etc may be needed. I don't know the full cost for sure. A new thermostat is about £10, a thermostat housing top cover is £20 or so new. A blank for the old thermostat fitting would be needed as well.

The way I thought about it was this; the full reroute kit costs $329 from FM in the States, so there's delivery and customs charges on top, so you could be looking at £300 plus to import a kit. What are the chances that the extra bits would cost me almost £250 to sort out if I bought this spacer?

I don't know of anyone in the UK offering a full reroute kit for the MX5, so importing a kit seems to be the only other option.

[skov]

It's the first time I've heard of the MX5 having cooling issues too!
If anything I always felt my MX5 was over-cooled.

If you do want to go with it there's acres of space in that area on the roadster:





Like porkchop says, the inlet side is very busy, and it might be a struggle bringing the hose down that side.
I recon you could easily bring it back on the exhaust side without getting too close to the manifold - I've got a big empty gap that side (just begging to be filled with a turbo!).

[CTWV50]

I remember reading something about this over a year ago so i decided to keep the heater matrix and use it as a radiator. Don't know how effective it will be but I suppose if this is a problem and we are all using a smaller radiator than the standard car and binning the heater matrixes some sort of reroute will be required.

[PorkChop]

All I originally planned to do was to run a hose from the back of the block and around to the side.

Plus I've sold the heater from my donor

[CTWV50]

Originally Posted by PorkChop

All I originally planned to do was to either run a hose from the back of the block and around to the side.

Plus I've sold the heater from my donor

Well no one has built a haynes with an mx5 engine yet so it may not be a problem! And people do stick V8 in them. Do they suffer cooling issues?

[PorkChop]

Originally Posted by CTWV50

Well no one has built a haynes with an mx5 engine yet so it may not be a problem! And people do stick V8 in them. Do they suffer cooling issues?

Not that I know of.

I think a small amount of confusion is coming through this thread. I'm not saying that if you do not use a reroute, your cooling system will overheat. What I am saying is that a reroute will improve the cooling to the rear cylinders (particularly #4) and make cooling more even across all 4 cylinders, thus improving efficiency. It should be of benefit to those who will tune (or plan to tune) their engines, or work them especially hard. If you look on the threads I've linked to, you'll see that the majority of people who have fitted a reroute have tuned engines.

I took the attitude that it was better to do something like this during the build and err on the side of caution (although I'm considering FI further down the line) than to build it all up and then find it needed tearing back down to make modifications because something was marginal. You might call it the belt and braces approach.

[CTWV50]

Originally Posted by PorkChop

Not that I know of.

I think a small amount of confusion is coming through this thread. I'm not saying that if you do not use a reroute, your cooling system will overheat. What I am saying is that a reroute will improve the cooling to the rear cylinders (particularly #4) and make cooling more even across all 4 cylinders, thus improving efficiency. It should be of benefit to those who will tune (or plan to tune) their engines, or work them especially hard. If you look on the threads I've linked to, you'll see that the majority of people who have fitted a reroute have tuned engines.

I took the attitude that it was better to do something like this during the build and err on the side of caution (although I'm considering FI further down the line) than to build it all up and then find it needed tearing back down to make modifications because something was marginal. You might call it the belt and braces approach.

Good point.

[PorkChop]

Just so you are all aware, the price has been confirmed as £70 (£65 + £5 postage).