Turbo Reliability

willanton · Postby **willanton** » Sat Jul 13, 2013 9:42 am

Hello Ladies and Gents,

I am currently in the market for a turbo NA8 to use as a weekend driver and track day car.

At this point in time, being a track day novice, speed isn't hugely important to me. I will look at further modifying anything I buy only when it gets to the point when I feel it's the car holding me back rather than my driving skill.

The most important thing for me is reliability. More reliability = more weekend / track fun = more smiles.

So, what are some common reliability issues with a turbo NA8 and what are the best fixes?

Thanks for any advice in advance!

Cheers

Will

sailaholic · Postby **sailaholic** » Sat Jul 13, 2013 10:10 am

Most likely problem with a turbo na8 is the turbo system.

Best fix, get a non turbo one.

Slower, but na stock is almost bullet proof if you keep fluid in them.

Sent from my GT-I9100 using Tapatalk 2

Postby **NitroDann** » Sat Jul 13, 2013 10:31 am

In terms of the system itself, the common issues are turbo>manifold and turbo>downpipe studs coming loose, along with heat control in the engine bay and poor tunes, followed by overheating.

I would suggest dont buy a low budget street mx5 that has a turbo and then take it to the track with no changes.

Replace the turbo studs with inconel, install with resbond.

Replace any worm drive clamps with T bolt clamps.

Have the tune checked by a professional on a dyno.

Check all oil lines for condition and if they are routed safely.

Check all brackets for strength and wear.

Brace the downpipe to the gearbox.

Put a flex pipe in the exhaust behind that.

Now you have the obvious stuff done, take the boost controller off and run stock boost for a few track days until you find the next weakest link, turn up a little more go again etc etc

Dann

timk · Postby **timk** » Sat Jul 13, 2013 11:12 am

All the points mentioned above, bits/fasteners tend to fall off during or after track days that wouldn't normally be a problem on the street!

Thermal management is a lot more tricky, you need to make sure you have good ducting and almost certainly an oil cooler.

You will also chew through more brakes and tyres compared to a naturally aspirated MX-5.

Sean · Postby **Sean** » Sat Jul 13, 2013 4:16 pm

All good advice posted above.

It'll likely be hard to tell the build quality/reliability of most turbo'd cars unless they've been out there and been running track days etc already.

Reliability can be greatly enhanced by the tune (if we are talking longevity). I always had my car running a little less timing and more fuel in the tune then where I could make peak power -an extra 10hp doesn't mean a lot if the car doesn't make it to the end of the race.

I'd argue a car with a proven kit would be a better buy than a custom built coversion, just because it's more of a known quantity, and if you look at the majority of race turbo MX5s, they are running the SP manifold and dump, or an AVO set, admittedly a lot of that is also to meet specific class rules...

How experienced are you at the track? There's a lot to be learnt in a nicely balanced stock engined MX5 with basic handling mods. I've owned a few MX5s including turbo and non turbo modded ones, and my current one is the most fun - completely stock engine :shock:

I like this thread and think it might be worth a read... viewtopic.php?f=57&t=56552

slimx · Postby **slimx** » Sun Jul 14, 2013 7:13 am

In all honesty, if it's tuned right you wont have issues.
The BP is bullet proof

I'd actually say the gearbox/diff would be a concern to worry about, because you'll take precautions for the motor itself but the gearbox usually people leave un-touched

manga_blue · Postby **manga_blue** » Sun Jul 14, 2013 10:24 am

If you'd gone to the MX5 CLub of NSW track day at Eastern Creek last week then you might have got your answer.

Run Group 1 contained the 10 fastest cars entered for the day. 6 of these were turbos. The other MX5s were naturals: one was highly modified NC (Daniel), one was a lightly modified NC (Ralph), one was a highly modified NB (Steve). There was also a very stealth looking white VW Golf.

After 3 laps of the first session of the day all 6 turbo MX5s inthe run group had retired. Then Daniel came in to check tuning. Leaving just 3 cars - Ralph, Steve and a VW - circulating happily. Caused a great deal of amusement in the pits because at the South Circuit all cars leaving the track come straight off the track into the one small crowded area where everyone sees what's happening. The rest of the day was typical with all the n/a drivers having an enjoyable day socialising and sprinting while all the turbo guys cursed and swore and sweated over and under hot engines.

Rule One is that you always read and understand the technical regulations for the competition that you're thinking of entering before you do a single modification.

Postby **NitroDann** » Sun Jul 14, 2013 4:24 pm

What were the issues?

And serious question, were most of the turbo cars on average much more modified in every way than the n/a cars?

Dann

manga_blue · Postby **manga_blue** » Sun Jul 14, 2013 9:16 pm

Main issue seemed to be that they were turbos and at a track day.

Cynical old bastard me. :roll:

We just watched them all limp off. I didn't have much of a look at them. Past experience tells me that trying to fix turbos at track days is like whacking crocodiles. Personal prejudice but I've done about 40 track days with the Alfa clubs and I think a 30-40 year old Alfa is more reliable than an MX5 turbo. I lent Patrick coils but it wasn't enough to get him 4 cylinders.

Steve's car is a pretty serious NB screamer. Daniel's is a 2.5 with a fair bit done, fastest time of the day. I think Ralph's is about mid-spec for an NC - the main track mod seems to be the driver. The Golf was a total mystery.

Sean · Postby **Sean** » Mon Jul 15, 2013 12:22 am

manga_blue wrote:Main issue seemed to be that they were turbos and at a track day. Cynical old bastard me. We just watched them all limp off. I didn't have much of a look at them. Past experience tells me that trying to fix turbos at track days is like whacking crocodiles. Personal prejudice but I've done about 40 track days with the Alfa clubs and I think a 30-40 year old Alfa is more reliable than an MX5 turbo. I lent Patrick coils but it wasn't enough to get him 4 cylinders.

Steve's car is a pretty serious NB screamer. Daniel's is a 2.5 with a fair bit done, fastest time of the day. I think Ralph's is about mid-spec for an NC - the main track mod seems to be the driver. The Golf was a total mystery.

I suspect the Golf was Boyracer?

As for track reliability, the only issue I ever had with my turbo was blowing off an intercooler pipe. Ran a couple of track days, hillclimbs and other events. Like I've said elsewhere - Better to run the set-up at 9/10 and finish the race than at 11/10 and push it onto the trailer to go home.

chops · Postby **chops** » Mon Jul 15, 2013 11:34 am

i was one of the aforementioned 6 turbo cars and my issue was blowing off an intercooler pipe. It was my first day out with a completely new setup and expected it wasn't going to be all beer and skittles so i wasn't too disappointed

i agree staying n/a is definitely more cost effective and easier to be reliable but i think reliability is possible with turbo cars. George Vergotis's car is an example of a reliable turbo car, admitedly he had an issue with coils that day as it just had a new Haltech fitted but sorted it and ran happily for the rest of the day. His car usually justs rolls off the trailer, goes fast all day and gets back on the trailer and has done countless track days and the motor is completely standard and never been opened. I ran my car for a few years fairly standard and had no issues until it broke a rod

it can be done but i do look at some of the n/a cars with envy as their day always looks easier. Having said that i feel the 'fun differential' between driving a turbo car and an n/a is worth the pain and suffering that can happen