VF35 Turbo-Daily

Welcome, nice write up!

Re. the misfire - on my Turbro one I always used the best plugs and leads, yet would still often get a misfire. I found I regularly had to regap my plugs (like monthly!)to stop spark blowout,but it did solve the issue temporarily.

I was looking at fitting COPs when I sold it. Might be worth looking into these if you still have problems after your new plugs/leads.

Well well well, Nutz has officially died it seems - so this will be the new home for my build thread! Luckily I have a backup of a lot of it, so here's a dump of what's happened until now:



22nd September

A relative shambles of a day yesterday. No pictures but here's the story:

I took the day off to change the leaking diff seal and hopefully attempt to fix the cross threaded spark plug issue. I started by removing the leaky side driveshaft which went relatively painlessly after I popped to Machine Mart to buy a gear puller. getting the seal out took a bit of work but I persisted and got there, with the new seal in I attempted to put the shaft back in but found the hub nut had crossed a thread on its way out somehow, so now I couldn't get a nut back on the shaft. Quick drive round the corner to Suffolk Mazda and £20 later, new shaft! Utilised my fancy new gear puller to get the ABS ring off it and on she went. All in all, around 4-5 hours including breaks and shopping trips.

Feeling confident, I whipped round to the front of the car, popped the bonnet and slung a socket onto the spark plug in question, at which point the plug sheared in half, leaving the thread locked into the cylinder head and leaving me holding half of a spark plug.

Canoe.



Went back to screwfix to get a left hand thread remover bit, but unfortunately I don't have the right combination of 3/8ths extension sockets to get a wrench on it while its down in the head. So, currently stuck with a car that works less than it did before I started fixing it. Nightmare!!

The cause of the plug shearing is probably over tightening, the last time I put the plugs in I gave it a little beans to try and get as far down the cross thread as I could, which was obviously a stupid thing to do in hindsight.

Shopping list:

3/8th extension bar
New set of NGK 7 plugs (they only lasted a week!!).

In an attempt to fix the misfire last week I changed the leads for some Jackson Racing leads, only yesterday did I realise that to fit these I'd removed a set of Magnecor 80's, which are more than twice the price of the Jackson's, think I should re-fit these as they're likely to be higher quality?



24th September

Good news!! Got an easy out on the broken thread and surprisingly, it came out easy!

Then got my fancy new bottom-up Clarke reverse thread tapper on the head and re threaded the crossed threads. Spark plug now seats perfectly and the HT lead sits flush down onto the valve cover. Proper job!!! All fixed for £25.

Bad news is, I still have a misfire above 6500rpm


2nd October

Few more updates, started progress on the interior part of the build, the PVC roof that the car came with was pretty horrible and the rear window was pretty much completely opaque, so i wanted to get the Mohair off my old car onto this one ASAP. Upon removing the PVC roof which was surprisingly easy I found this odd piece of bendy plastic rivetted onto the bottom, the old roof didn't have this... After laughing at myself for all those times I wondered why the old roof was leaking, it's because it didn't have the bit attached that stops the water getting in... I slotted the rain rail into the car and then fitted the new roof temporarily so that it can withstand the rain.




Interior looking quite bare!



Also got to work hacking the hell out of the parcel shelf so I can get the roll cage in.



Rough cuts for now, I also started cutting the plastic trims in an effort to make the install look moderately "OEM". Pics of that incoming once i've tidied it up a little!

Things to do:
Repaint metal roof rail
Prep and paint trim pieces to fit around roll cage
Drill holes and test fit cage
Clean the interior thoroughly and paint all bare metal that's been cut / modified
Fit cage and refit interior

From then on, I need to get a steering boss, change the brakes on all four corners and modify the arches to fit the ET0 wheels under. After all that's done, I can get to work fitting COP's and putting a new set of NGK 7's in so I can finally get the car back to Hybrid Tune for its mapping!


12th October

Took a day off from work today to get some things done, ended up battling a horrific cold all day!! sad.

Nevertheless, battled on - probably for the worse of my health - but at least I got some things done.

Bought a set of these the other day:




Certainly cheaper than an impact wrench and do the job great for unwinding nuts and bolts after you've cracked them. Also means you can get things whizzed on real quick to test fit.

Stuck one on my cordless and got the roof off in around 3 minutes!



Put a few bits of touch up paint on the scrappy rails



And finally got the cage in



Sneak peak of the finished result - better pictures coming tomorrow.



After the roll bar and the carpets were all back in, I ended up swearing at my seats for 20 minutes because they somehow weren't fitting. I was completely stumped as to how I can unbolt them from my last mx5 and then find that they don't fit this one.. The only thing I could think of was that the car had been in some kind of really hard impact and the whole thing was bent! Until of course I realised that the two seat rails weren't in synchronised positions so the whole thing was skewed when fitting. DOH... Glad I didn't start butchering the mounts before I realised!

Also fitted a new steering boss so i can get a nicer wheel on, I discovered that the universal horn push that came with my cheapo steering wheel has two connections, whereas the Mx5 only presents me one connection. So, added a new horn push to the shopping list, will probably pop down to Suffolk Mazda to dig through their bins (and inevitably leave with a million things i didn't intend on buying!)

Whole thing is starting to come together now, I still need a full alignment doing - tempted to try and save some money and do this myself with some string somehow.. Also need to find a way to get the wheels under the arches. The two rear arches are a little rusty so some choppery may be required unfortunately.

Better update with more pics tomorrow.


13th October

Few more interior pictures!








Interior wise, I still need some new floor mats, a gear knob and some door trims. Considering doing something custom and fancy with the door trims..


16th October

SCIENCE!

So, trying to diagnose my misfire using the data available to me. I've done some datalogging on my ME221 and here are some... interesting results.

Graph of Injector Duty vs RPM, on two separate pulls that both had misfires occuring towards the top end.




So as you can see, I'm hitting above 90% injector duty. The next graph is perculiar:



I've overlaid the Injector Max Duty Count, which is an 'error' stat produced by the ME221. Interestingly, in the first pull where I hit a whopping 98% Injector duty, there weren't any errors produced. However, on the second pull where I only hit 93% Duty, I got 2 errors. Now, this could be down to the relatively low frequency rate I used when logging which was only 10hz. Later on today i'll get out and do another logging run with a higher frequency and hopefully get some more answers.

So conclusions from this so far? There don't seem to be any stats that will help me diagnose whether or not the issue is related to ignition, not sure if anyone has any wisdom on how to check if my ignition is firing as strong as it needs to be. Someone on the Nutz FB page suggested that it may be down to the fuel pump, which will affect the Injector Duty readings if the pump can't keep up with demand.

Today was COP conversion day!

NEVER done anything electrical in my life, so having spent the past few weeks researching what I needed and how to get things done, this was certainly a nervous afternoon.

Test fitted the COP's and the bracket I got from TheMX5Restorer - it fits perfect! Offered up the wiring to try and get a good length so it can plug into the main loom nicely.



Wired the original loom plug onto the end of my cop loom, a true plug and play COP setup, which is what I wanted from the outset! Sat the cops in the holes and it connects up nicely.



Once I was confident it all fit, I gave it a test fire and it started first time perfect, running really sweet. This absolutely shocked the hell out of me having never even used a soldering iron before. So, back off the car and into the house to tidy up the wiring. Once this was done, back out in the dark and onto the car.



Install done, not too difficult after some help from Nutz'ers.

Took the car out for a drive to see if it had solved the misfire and guess what!!!

Nope. Still misfires. In fact, it was even worse..... sad. sad.

So, plugged the laptop in and dropped the dwell to 2.5ms and got it settled down, now running better but still misfiring up top. It seems as if the problems aren't ignition related! At least I've got a more robust setup now. So whats next? Fuel pump? I'm tempted to take it back to Hybrid Tune to see if the misfire is map related as the old car had exactly the same misfire, but I don't want to end up chucking money at a dyno / map session to find out I then need to back away and replace a fuel pump or whatever.

16th December

Car has been at Hybrid Tune for the past week or so, today I picked up a non-misfiring car for the first time ever. Chuffed! It was indeed hitting injector duty cycle as I'd observed before but it was mainly down to the tune, with no wideband installed I had no idea what AFR it was hitting and as it turns out, it was running pretty damn rich for all that time, so once the fuel tables were dialed in the car runs really sweet.

Once the car was fueling properly, it did start boost creeping - which is apparently a common issue on VF35 turbos, to fix it we had to port the wastegate out inside the turbo to help get rid of excess air, once done it boosts quite nicely - not perfectly though, it could probably do with a fancy external gate setup but at this point I'm happy to have a car that just works for once.

Here's the graph:



The car makes 247hp peak @ 9psi, there's still so much more left in the turbo but unfortunately there's no more left in the injectors as they're hitting ~90% duty. I had the option of fitting some blue RX8 injectors and pushing for more power but as the engine has 120k miles on it already I don't really want to start pushing towards 300hp, I like my rods straight.

On the way home I could hear the unmistakable hiss of boiling water, turns out one of the hoses that go into the heater matrix is leaking at the join, which might just be a dodgy clamp or its perhaps not pushed all the way on - I'll get out in the morning and put a nice new hose clamp on and make sure its all sealed.

Apart from that, car runs great now, no misfire / cut at all and it goes pretty quick! I have to say, it's not as quick as I'd have hoped at 250hp, perhaps there's some weight saving that needs to be done to get a little more performance. It also seems to pull to the right under power, and coincidentally the handbrake is absolutely naff on the rear right side, so I think perhaps the handbrake mechanism / cable is stuck somewhere and is binding slightly. Once that's fixed I expect it'll go a tiny bit faster.

Next up, brakes, wheels, tyres and track days!



18th Feb

Finally got some time to get started!

Only trouble is, how do you take a set of spacers off without someone to press the brakes for you?



That's how!!

Old pads still had around 8mm left on them, not too bad.



Discs weren't too nice though.



Much better. Couldn't get the pads in with the shims in so for now they're in without, if it squeals too bad I'll put the shims back in once the pads have worn enough.

Front N/S took around 90 minutes to do, but this was the first time I've done any brake work so plenty of that time was figuring out how to do things. Most tricky was fitting the new pads onto the new discs, even with the piston pushed as far back into the caliper as I could the pads would hardly fit, had to use a set of gear pullers and a long socket to get the piston as far into the caliper as possible.

After that, I did both the disc and pad on the O/S front in around 15 minutes! Going to do the rears tomorrow if I get a chance, then its time to strip the interior and refit it as minimal as possible.

Hey

Awesome thread, looking forward to seeing the aero mods!

Tazza

It might be worth having a chat with the Funk soul brothers about a blanket or wrap. They used to give Nutz members a discount and might do a similar thing here. #Notsureiftheyarebrothersorhavesoul

Ps. Nice weld! 

Awesome result on the racing stuff I'd like to be good but I am really not lol