Coolant reroute

[Mr MXT]

Worth the hassle or a pointless waste of time?

Talking FI cars.

Discuss!

[piefacemate]

Not come across this before.

I'm assuming you're talking about rerouting the radiator pipes?

[Mr MXT]

Ignore the annoying man, but he explains the problem better than me.

http://www.youtube.com/watch?v=mRharubfD1E

[piefacemate]

He is an unusual character. Makes me think of Noddy Holder for some reason.

This website has some pictures helping explain it too.

http://www.miatamx5.com/coolantreroute/index.html




Not come across the issue before I must admit, but have to question the comments on the above site about the effectiveness of cooling upgrades via a higher CFM fan or larger radiator.

I'm running a much larger than standard radiator resulting in the temperature gauge rarely getting above 1/2, and the car never (yet!) having the fuel cut via the ECU's temperature threshold. Since, according to the diagrams, the MX5's thermostat is located within the head, it should be giving a good indication of the true temperature of the coolant where it matters.

Or am I missing the point here?

[Mr MXT]

On my phone so excuse brevity.

I think the issue is that the rear two cyls run hotter than the front, thus on an fi car increasing chance of det. This mod even temp across all cyls.

The reason I have been looking into it was to solve a side issue I'm having with a coolant hose, and trying to avoid going from heater matrix to turbo

How is yours routed, with pics? :-)

[piefacemate]

Mine's not been rerouted, was looking at it at weekend. Happy to go get you some pics if you tell me which bit you need photographing!



The above is the rerouted coolant method.

Where does the heater matrix reroute to? Or is it just a flaw of the rubbed out parts of the diagram?

Otherwise, doesn't look too difficult to do providing you can get hold of silicone hosing of the right shape.

[Mr MXT]

I wanted to know how you existing coolant routes to turbo so I can compare to mine. Ta!

[piefacemate]

Bit dark in the garage and the bonnet blocks the strip lights, so excuse the stty iphone flash quality!

[Mr MXT]

Thanks!

I'll show my "Project Manager" and see if he can figure it out. It definelty seems to be routed better than mine.

[Richyvrlimited]

piefacemate said:

I'm running a much larger than standard radiator resulting in the temperature gauge rarely getting above 1/2,

You won't ever see it pass halfway as the OEM temp guage has a 'dead zone' of around 50degC, it hits the mid point around 60degC and stays there till about 100degC.

In terms of reading tremperate the OEM guage is nearly useless. That said you can modify it to provide a liner output. It isn't like this from the factory as Mazda had enough trouble from owners asking why the oil pressure guage moved all the time.

piefacemate said:

and the car never (yet!) having the fuel cut via the ECU's temperature threshold. Since, according to the diagrams, the MX5's thermostat is located within the head, it should be giving a good indication of the true temperature of the coolant where it matters.

Or am I missing the point here?

The coolant route as standard is sub-optimal. This is primarraly because the thermostat is at the front of the engine, wheras the engine is/was out of a FWD/4WD 323 and was designed with a termostat at the rear of the head.

There is lots and lots of reading on the coolant re-route on miataturbo.net It's a very good thing to have on a FI'd car, particularly one on track as it evens out the coolant distribution and stops cyl no4 from getting much hotter than the rest - as happens in the stock configuration.

One thing to note though is the 2001+ engine (ones with VVT), shouldn't have a coolant re-route performed on them. Mazda modified the headgasket to achieve a similar effect, doing the re-route on a 2001 engine will cause cyl no1 to overheat in relation to the rest.

If you want to remove the 2001 HG and replace with an earlier one and then perform a re-route feel free it's a more effective job than Mazda did with the HG

[Mr MXT]

Richyvrlimited said:

The coolant route as standard is sub-optimal. This is primarraly because the thermostat is at the front of the engine, wheras the engine is/was out of a FWD/4WD 323 and was designed with a termostat at the rear of the head.

There is lots and lots of reading on the coolant re-route on miataturbo.net It's a very good thing to have on a FI'd car, particularly one on track as it evens out the coolant distribution and stops cyl no4 from getting much hotter than the rest - as happens in the stock configuration.

One thing to note though is the 2001+ engine (ones with VVT), shouldn't have a coolant re-route performed on them. Mazda modified the headgasket to achieve a similar effect, doing the re-route on a 2001 engine will cause cyl no1 to overheat in relation to the rest.

If you want to remove the 2001 HG and replace with an earlier one and then perform a re-route feel free it's a more effective job than Mazda did with the HG

So richy, how would you go about plumbing in my turbo? Currently its "non reroute" and the coolant to the turbo comes from the matrix (i.e very hot).

I want to change it to something much more effective!

[piefacemate]

Richyvrlimited said:

piefacemate said:

I'm running a much larger than standard radiator resulting in the temperature gauge rarely getting above 1/2,

You won't ever see it pass halfway as the OEM temp guage has a 'dead zone' of around 50degC, it hits the mid point around 60degC and stays there till about 100degC.

In terms of reading tremperate the OEM guage is nearly useless. That said you can modify it to provide a liner output. It isn't like this from the factory as Mazda had enough trouble from owners asking why the oil pressure guage moved all the time.

Is this a limitation of the temperature sensor or the gauge itself? Previously I would measure the temperature of the car using the ECU control panel, which equated roughly as 1/3 on the gauge ~90 degrees to 2/3 ~ 120 degrees. The car would then cutoff the fuel under acceleration until temperatures fell to a safe level.

I'd frequently see it pass midway on the standard radiator, even with placid driving; the race radiator never goes over half, unless on a sprint in hot weather where it can start edging above. On track, however, I would expect it to 2/3 and hover around that mark, dependent on atmospheric conditions of course.

Does this sound like a modified gauge in your opinion? It wouldn't suprise me as it's had that much done to it over the years by the previous owners.

Richyvrlimited said:

piefacemate said:

and the car never (yet!) having the fuel cut via the ECU's temperature threshold. Since, according to the diagrams, the MX5's thermostat is located within the head, it should be giving a good indication of the true temperature of the coolant where it matters.

Or am I missing the point here?

The coolant route as standard is sub-optimal. This is primarraly because the thermostat is at the front of the engine, wheras the engine is/was out of a FWD/4WD 323 and was designed with a termostat at the rear of the head.

There is lots and lots of reading on the coolant re-route on miataturbo.net It's a very good thing to have on a FI'd car, particularly one on track as it evens out the coolant distribution and stops cyl no4 from getting much hotter than the rest - as happens in the stock configuration.

One thing to note though is the 2001+ engine (ones with VVT), shouldn't have a coolant re-route performed on them. Mazda modified the headgasket to achieve a similar effect, doing the re-route on a 2001 engine will cause cyl no1 to overheat in relation to the rest.

If you want to remove the 2001 HG and replace with an earlier one and then perform a re-route feel free it's a more effective job than Mazda did with the HG

Now you're just adding to the work I need to do before summer

I can, however, see this being a major pitfall on track as everything might read normal while piston #4 melts. In a Haynes style 1 spanner for easy, 5 spanners for pay a specialist, however difficult would you grade this modification, and how easy is it to source the necessary bits as I'm assuming they're all custom?

[piefacemate]

Mr MXT said:

Thanks!

I'll show my "Project Manager" and see if he can figure it out. It definelty seems to be routed better than mine.

No worries. I'm crawling underneath it this afternoon to try and sort the squeaky alternator belt, so if there's any you need better shots of just let me know.

[GravelBen]

If its any help, mine looks like this:



I expect its different between 1.6 and 1.8 though - don't know too much about the details as the engine work was done by previous owner.

Edited by GravelBen on Thursday 10th March 11:10

[Richyvrlimited]

Mr MXT said:

So richy, how would you go about plumbing in my turbo? Currently its "non reroute" and the coolant to the turbo comes from the matrix (i.e very hot).

I want to change it to something much more effective!

All the available kits generally take their feed from the mixing manifold (the outlet of the waterpump), this is perfectly fine as a source. The oil feed does most of the cooling on a turbo anyway.

You don't want cold water straight from the rad as that'll induce thermal shock.

[Richyvrlimited]

piefacemate said:

Is this a limitation of the temperature sensor or the gauge itself? Previously I would measure the temperature of the car using the ECU control panel, which equated roughly as 1/3 on the gauge ~90 degrees to 2/3 ~ 120 degrees. The car would then cutoff the fuel under acceleration until temperatures fell to a safe level.

The deadband is built into the guage, the actual sensor for the dash is a tiny 1 wire sender in the back of the head.

Temp senders aka thermistors are just a resistor that vary their resistance dependant upon temperature.

[quote]
I'd frequently see it pass midway on the standard radiator, even with placid driving; the race radiator never goes over half, unless on a sprint in hot weather where it can start edging above. On track, however, I would expect it to 2/3 and hover around that mark, dependent on atmospheric conditions of course.

Does this sound like a modified gauge in your opinion? It wouldn't suprise me as it's had that much done to it over the years by the previous owners.

I'd certainly hope it's a modified guage. As soon as my guage starts to move past 12 O'clock, I'm WELL past 105degC wich is about as hot as I'd ever really want the engine to get anyway...

Richyvrlimited said:

Now you're just adding to the work I need to do before summer

I can, however, see this being a major pitfall on track as everything might read normal while piston #4 melts. In a Haynes style 1 spanner for easy, 5 spanners for pay a specialist, however difficult would you grade this modification, and how easy is it to source the necessary bits as I'm assuming they're all custom?

If you're really averse to fabrication, you can buy a kit from M-Tuned, (re-sold by various companies i.e.949 Racing, Rev9, FM Etc), BEGi have their own version and it comes in 2 flavours, the cheaper one I'd avoid personally it's sub-optimal. On the haynes scale it's a 1 spanner with the caveat that the bolts on the rear of the head are a complete st to get at

[Richyvrlimited]

GravelBen said:

If its any help, mine looks like this:



I expect its different between 1.6 and 1.8 though - don't know too much about the details as the engine work was done by previous owner.

Edited by GravelBen on Thursday 10th March 11:10

Looks like it has BEGi's 'street' reroute is already applied, No offence but it's not the greatest implementation of a re-route, it is the easiest to install however.

Also not a fan of the coolant taking a path directly over the exhaust manifold.

[Richyvrlimited]

At the risk of replying to the same post again

http://www.miataturbo.net/showthread.php?t=35540&a...

Pretty much anything Joe Perez writes is worth taking note of, but this is his install of a BEGi reroute kit. explains pretty easilly what's involved

There's a pretty epic thread on mt.net started by a user called 'Hyper' on his version of the coolant reroute, it's a retarded idea of his, but if you skip past his crap there's some good explanations on there about the re-route and why it's effective.

Don't bother past page 5 or so, it just ends up being Hyper having a pissy fit and not understanding the flaws in his ideas, and then getting banned.

[Mr MXT]

Right chaps, I think we are going to do something along the same lines as this, got any opinions?

[Richyvrlimited]

Mr MXT said:

Right chaps, I think we are going to do something along the same lines as this, got any opinions?

That's the 'best' and easiest way to do it.