Looking after Roadster turbo

 

Hello,

 

I’m new to MX5 ownership and am lucky to have been able to buy my first 5 from another owners club member.

 

As well as being my first MX5, it’s also my first car with a turbo. I’ve spent a fair amount of time working on Morris Minors and old Minis etc, but there are a few things for me to learn about the world of forced induction. My primary aim is to look after the car so with a few of my questions I’m really thinking about long-term reliability and preservation.

 

The car came with a ring-binder full of receipts and other information, so I’m lucky to know most of the details of the work done. One thing I’m not sure about, is how much boost the turbo is currently making. The engine work was done around 8000 miles ago and involved a full strip-down of the engine, not just a bolt-on. Included with the car are dyno-prints showing a 200bhp output. I know that over the past few years, though, things might have changed (is boost-creep a thing?) so that’s one thing I plan to find out. I suppose ideally I’d get a boost-gauge, though I want to plan how to integrate that neatly.

 

With 200bhp being made in the past, am I right to think that the car cannot have stock injectors for a 1.6? I know that the fuel-pump has been up-rated during the work, but I don’t know about the injectors specifically. I’ll try to upload a picture of these as well in this post.

 

I’m assuming also that the wastegait will prevent too much boost, although I know that this mechanism can also fail. That then leads on to the ECU. The car has a Link G4 - I’ve no idea what the settings/map is like just now, but I’m assuming that there is some kind of over-boost protection and knock protection built into that.

 

In terms of looking after the lifespan of the turbo itself, I’m also wondering about fitting a blow-off valve. The turbo makes a lovely flutter sound when you lift-off, and I’ve heard mixed reports about how much damage that might do. I’d like to play it safe, though. On the topic of turbo life-span, I’m also planning to connect the water cooling lines. Again, there seems to be mixed opinions about the value of this, but if it might help at all then doing it seems worthwhile, especially since it’s easy enough to do.

 

Thanks for reading - any tips/pointers really appreciated!

Morgen

 

 

Having a look around online I think maybe it has the brown-top injectors that were specced for a Supra? I’ll need to get a proper look at them soon and see if I can find a part number.

I was in a similar position, buying a car turbo’d by someone else. Even though I had details of the kit fitted and some rolling road plots, there’s not really anyway to be certain that it hasn’t been fiddled with or deteriorated over time (altho afr and boost gauges might indicate engine health).

I had mine rolling roaded again and it turned out the settings were well out. It wouldn’t have passed an emissions test.

I also found my turbo water lines disconnected. Now some turbos are exclusively oil cooled, but if water lines are fitted then it’s meant to be water cooled and I’ve now plumbed mine in. However I did send the turbo away to be checked over and it came back with a clean bill of health.

With regard to BOV I can’t really comment on that other than to say 200 bhp isn’t particularly highly stressful to a mazda lump.

Ben