Hellmun's NB8B

[Hellmun]

Well bit of an update though nothing that massive. I dropped the diff off in January to Daniel and he pulled it to pieces and said he couldn't really find anything too wrong with it. It now has all new genuine seals and bearings though and he shimmed the plates to make the diff a little tighter and reversed the plates so the reverse faces are now the forward facing ones and vice-versa. Unfortunately the diff is still making some awful noises which I'm guessing is some warping to the clutch plates faces in it, it's not constant like before and really only happens off throttle. So definitely seems like I damaged it on the trip home, it's a very distinctive ceramic rubbing noise. That said once your on full throttle the diff is locking extremely tightly, noticable more as it's slightly more biased to understeer now which I'm trying around with a little light trail braking on tight corners.

The diff arrived back with two weeks to spare to go in the Mx5 clubday on the 20th of Feb. Then I had new more annoying issues. Firstly my car would no longer start. It has the original factory battery still so it's now over 10 years old and the car had been sitting dormant for a little over 2 months. So I grabbed my starter pack, started the car and decided to take it for a drive to charge the battery up a bit. First attempt I got about 2.5km's away from home before the car cut-out. Next attempt I got from Wollongong to Robertson in one go. Only issue was the car was misfiring if I tried using the power windows . I stopped at the pie shop, grabbed a drink and went to start the car. The starter barely turned at all which was worrying. So on went the charge pack and off we went again down Jamberoo pass on a very very wet day. It was getting late by the time I got back down to the freeway and I turned on the headlights thinking it would be fine...instant stall. So at this point I thought I was up for a new battery and started trying to find somewhere to get another one. After some research though and the fact I only had 1 week to replace it before a trackday which I wouldn't be doing without a reasonable battery I bought a jaycar trickle charger. It took 3 days but amazingly the battery has recovered %100....

Next issue is one of my 949's has popped a small air bubble in the casting and one wheel was dead flat on the Saturday before the clubday. I covered it in silicon, left it 8 hours and then pumped it back upto 36 psi. I checked it in the morning on the car and it was only down to 35psi but figured it should be alright for the clubday, that might only be the cold temperature.

For the first time I think ever I didn't kane the car immediately from the start of the day. I'd been having a bit of a tooth problem which had just started and giving me a lot of sensitivity and a headache to boot which didn't. Car wound up incredibly stable and had no problem with the longer sessions the club was running. Diff was tight, tyres stayed up and the battery stayed charged but it's still taking some adjustment to be as smooth with the button clutch as I was with the standard one. I only managed to get my car into 10's which is slower than usual. Highlights of the day were definitely driving Luke's turbo mobile which has way more power than grip, the stock SE suspension is definitely not much stiffer than a standard NB. Then after that I got to Drive Brett's turbo NB aero-monster which was a completely different beast again. It only had 130kw atw which is conversative for a boosted 5 but wow did it have rear end grip thanks to the big wing. Only issue was trying to get it to stop as only half the pedal had it trying to lock the front wheels. Still the motor was amazingly smooth with it's power delivery and a awesome fun to drive. I didn't drive my car anymore after that, my headache was getting the better of my so I called it a day. Unfortunately that wasn't the end of the day... on the way home in convoy with Peter Feutril I ran into my cars old demon. The loss of throttle position and inability to hold a speed started yet again... The car even stalled a couple times randomly right up until we hit Macquarie Pass and then it came good again.

After that I organised a dentist appointment which ended up the day before the Supersprint...and it turned out I had a wisdom tooth coming through and it had remove the gap between teeth and lifted one of my teeth out of the jaw which had been what was giving me the grief. Seeing as the other tooth was already part-way out and was only going to get worse the dentist removed that molar... which was WAY worse than I expected. I ended up missing the already paid for supersprint as I was in no condition to drive and was not allowed to get my blood pressure up until my gum had healed. That pretty much sealed me to giving Supersprints a miss this year.

Since then I've bought a few toys for the Mazda and performed two repairs. Firstly I got a new fuel filter to try as the car has hit 80,000kms now and Daniel Deckers suggested I replace the filter to try and sort my throttle position loss. This ended up being an incredibly tedious job as my bracing was locking the cover in place over the filter and I couldn't stop the lines leaking with a gold tee like I had heard. So off went the bracing and wasted atleast a litre of fuel but the car seemed to gain throttle response just idling after replacing it. So I cut the old filter in half and it had quite a lot of particulate matter in it... so that Shell on the way to PI might've had a rusty tank or something and blocked the filter.

I then ended up up buying TCR's DL1 datalogger which was at a price too good to pass up so I can keep trying to get what I can out of the car. That of course needed a laptop to go with it so I could tune at the track... so kinda an expensive month and a massive fail at saving for that turbo conversion . I've also bought a toggle switch, inline fuse, LED light and 3 new gauges to make up the new centre console and be able to cut power to the DL1. So far I've made up a new aluminium mounting plate and just need to do the wiring now to install it in the car. Also noticed that the last of my heat wrapping on the exhaust had perished and being that the brake line in the NB8B runs within 8mm of the Racing beat headers I decided to re-wrap it. I got the wrap from Just-jap when I ordered the gauges and be warned that the glass fibres really damage your hands...especially when your pulling the wrap tight while working on the headers which are still in the car. Still I did it significantly better than I had previously and the engine bay looks much neater with the scrappy old asbestos cloth.

Next fun issue was the 949's again.. the silicon burned up while on the track and the tyre was empty again after only a few weeks. Seeing as I left it WAY too late to organise a wheel repairer to have a go my Dad had a idea. He set up an old fridge compressor and used the vacuum side and put a vacuum on the rim with tyre. Then used loctite over the hole and let the vacuum suck it in a few times, then pulled the valve, let it return to normal pressure and covered the whole with some paint. Then left it one day until pressuring it to 36psi. It held pressure for over 3 days at this point.... and nearly a week now after the club-day on the 9th of May it is still holding pressure.

[Hellmun]

Well barring all the work on the car there were 2 more fun events that occurred in the last 2 months worth mentioning. Mike invited me to be a trainer at MDTC which was a MASSIVE amount of fun to drive on. Met a lot of great people too. I think lunch was the only time I wasn't in a car the entire day! I took some film and the best time I managed going off the video is a 44.6s which I have no idea whether is good or not. Bryan also had a go driving the car and from what I hear had a blast which is re-assuring I'm onto a good thing with the cars setup. I also got to drive a number of 5's and get to see such a massive diversity between the same model cars. The MDTC is incredibly tight, full of elevation and camber is makes the 5 feel completely like a go-kart. Hugely fun day and I'd definitely do it again if I had the chance.

Next there was also the clubday this sunday. I treated it a bit differently to my other clubdays and didn't actually check the times hardly at all. I spent all morning just driving and catching up with a lot of people. All I did was keep 32psi in the tyres and focus on driving smoothly. Amazingly... after Bryan took the car for a spin during lunch I jumped back in the driver seat on session 4 and set the fastest time I've ever done...and I didn't even notice . 1:09:35 and amazingly.... that was the session I didn't get on the go-pro . After that I figured I wasn't going and quicker and let a few other people have a go in the car. Luke managed to take it round for about a 1:14, then Steve jumped in to have a go and let me have a go in his car. He got handi-capped by not getting enough time to adjust the seat forward (me and Luke are over 6ft and the harness is not easy to adjust) so could barely touch the pedals. Steve's car was incredibly stable, had heaps of grip and had such a great wide powerband. The CAMS and ECU make an awesome difference but with the 5 speed you sit in gears for so much longer and it feels so different to my car to drive. The 5 speed has a really positive engagement and falls into gears much easier without needing force to recentre it quickly. With my 6 speed I find I need to be much more aggressive to change gear quickly and it doesn't return to neutral as easily by itself. I'm not actually sure what times I managed in Steve's car but it felt like it had wicked potential in it. I think Steve's going to get into 11's and then 10's in the not too distant future.

Next up me and Tony swapped cars and I got to have a go in a modified 1.6 this time. Funnily enough I think it actually is quicker than my NB in the straight, his car was slightly less neutral (only barely) and was amazingly frisky. I'd forgotten how much turn-in I've lost running toe-in and an overly tight diff, driving Tony's car it aggressively pulls itself into corners with barely any steering input at all. The corollary to that is it needs a little counter steer to keep it in the right direction all the time when pushing it as the rear doesn't quite follow perfectly. It feels a lot more exciting than my car to drive and I loved it... I was being a little cautious as the last thing I wanted to do was flat-spot a tyre on him so I wasn't braking as hard as the car felt it could go..and we're pretty sure I did a very high 1:11 in it. After the session I jumped back in my own car for one last run..which was a mistake as god it felt dull and being that it had 4 relatively rapid sessions I overheated the tyres and wore the centre of my A050's.... still definitely one of the most funs club days I've ever had. I was going to take a break from clubdays to keep saving money towards the SE turbo conversion.... My Father said he wants to come and see a club day though so I'm definitely going to do the next one atleast one more now. Doubly because I'll have the DL1 and gauges so I can have a base-line for the car before the turbo

[NitroDann]

Ive made some promises to friends that Ill get to wakefield on R comps before My car gets any boost. If I have aero am I still entitled to chase your record for a treaded tyre street car?

Dann

[Caffeine]

From your videos it looks like you change into 5th at the start line at Wakefield. In my stock NB8B I was changing into 4th there on a good lap! (pre-resurfacing)

Very impressive stuff

[Hellmun]

Officially no, though people are already running mini splitters, lips and all kinds of cosmetic and aero enhancements without grief. No-ones racing for sheep stations so the club is pretty relaxed which I think is a positive thing. That said I know when I first started I got moved from standard to modified for only having 17" wheels and nothing else so technically your into Race car class if scrutinized. Anyway that record will be gone in a few months regardless, records reset annually so you'll be chasing Phil/Steve/Tony/Ralph more likely who will have the record next year. The records are always getting lower ...when I started the class record was 1:13:28 and now there are so many cars smashing that.

[Hellmun]

My car has the NB8A 4.1 diff so I'm doing way less speed per gear than you would've been Caff. I reckon it's harder to drive a standard car on the limit than a modified one so big respect for a getting under 1:17 on street tyres.

[NitroDann]

Looks like im chasing 9s with hopes and dreams. And the hope of more straight line speed than you. Huge task. How much do you think your diffs worth compared to a torsen?

Dann

[Guran]

Thanks again for taking me out for a drive in your car on Sunday, Mark. The car felt great! It has soooo much grip in the corners and under brakes that it took me a while to adjust to the difference. That button clutch is tricky too. The steering is VERY heavy so I imagine you must put an extra inch of muscle on your arms after the Wakefield 300! I'd definitely like to have another go at the next club trackday for a timed run.

Jumping back into my car after lunch really emphasized the difference in steering weight and the need to carefully manage weight transfer in corners and under brakes.

Incidentally, your run in Tony's car was timed at 1:12.99 ... it was a new class record at the time. Then Tony did his first ever 12 with a 1:12.80 in the last run of the day!

[Caffeine]

My car has the NB8A 4.1 diff so I'm doing way less speed per gear than you would've been Caff. I reckon it's harder to drive a standard car on the limit than a modified one so big respect for a getting under 1:17 on street tyres.

Even with the diff you're still dramatically quicker. Anyone who drops the lap record by 4 seconds is to be applauded!

I've been tempted to come down and have another go now that the track has been resurfaced, but my car is officially 'modified' now (smb exhaust) so I would be up against your time

[Hellmun]

Bryan - During the wakefield 300 in 2008 we used Andrews car which we'd just de-powered the rack for that week. He'd even dropped the caster back a bit to keep it lighter and after 45 minutes I was down to one hand driving it. Then I depowered mine a few months later and left the caster as max and my forearms were always dying during the day. So start of 2009 I started going to the gym and now that my arms are over 9cm wider I don't have grief anymore . You and Steve can definitely take it for a proper timed run next day.

Dan - That diff of mine is a compromise in a car with my power. Have a listen to the fishhook in any of those youtube videos and hear the engine fluctuate up and down slightly as it gets on power. That's the diff locking and bogging the engine and trying to push the car wider.... I think my car would be faster on a torsen in any low speed corner. Same thing happens in turn 9 where you need to have very small steering input or the car shakes. Still having the diff that tight lets you hit ripples if you need to with full-power where the torsen would be free-spinning. I rub the ripples on turn 3, 4, 8 and drive over them on Turn 5 and 6 which would unsettle a torsen equipped diff. Car will bog down if I don't use 2nd in Turn 9 (which I had to change to 225/50/15 tyres to make usable) and I always gets slowed in the fishhook as it fights the understeer (conversely aggravated by 225/50/15's). It causes issues on any low speed corner so if the power isn't there is to give some slip you'll go slower. I'll show you some video on Marulan which really exacerbated it. Plus mine is also a 2-way so you need to be dead straight when braking hard as well as it'll want to lock rears quick as the diff assists the one braked wheel towards the direction the cars pointed ... I've learnt to drive around it but expect some adjustment to get the most of it. On top if your streeting the car a lot parking will damage your half-shafts, the locking is very violent. It's a lot of compromise but it is brilliant in the wet and when you find that sweet spot.

Caff - I think the surface has settled a bit, it felt quicker after it was done which I'm guessing was the roughness of the fresh asphalt but I think the surface has smoothed by now thanks to all the drifter. The exhaust couldn't be worth that much so it'd still be a good idea of whether being able to jump pretty much every old ripple made the old track faster or slower. I just wasn't an experienced enough driver on that old surface to know. I don't even remember what my best time was by that stage....

[greenMachine]

...when I started the class record was 1:13:28 and now there are so many cars smashing that.

I remember that ... sigh

You have done a great job Mark, and I look forward to catching up in July at the 300.

[Hellmun]

Updates!

Well not much mechanically has changed on the car but I do have a few results for changes. Firstly the trickle charge is AWESOME. Have not had any battery issues at all since so 10 years on the factory Panasonic is still working great. Secondly my issue with throttle loss has not re-occurred once since I replaced the fuel filter so respect for Daniel D for the idea. Lastly my issue with my 949's rims leaking. I finally got it to Spot-On wheel repair in Unandera, the staff member looked at the rim and simply said chasing leaks with welding is expensive and not guaranteed. I'm much better off just scrubbing the wheel clean and simply putting 5-7 coats of rattle can paint over it to fill the gaps. I'll probably do this within the next month or so but definitely after the next trackday.

Next I have a few new toys to try, I got a Orange TPMS system which incorporates pressure and temperature for each wheel so I'm going to get an idea how fast temperature increases/decreases and compare weaving, hard braking and temperature/pressure ramp up rates. Hopefully I'll get this installed on Saturday before the club-day as I really need to rotate the tyres but we'll see if time allows.

In addition I've finally installed the DL1 datalogger, Dash 3 and gauges (oil Pressure, temp and water temp). Due to birthdays, buck's parties etc it has taken me ages to actually get time to work on it up until now. This was harder than expected due to little things I wasn't expecting. Firstly when I first installed the sandwich plate I found that I couldn't actually get an oil filter on without fouling a brace. Further reading and I found out it's just used to support the intake manifold and the brace is not needed unless your carrying the engine by it. So I removed it, installed the filter back on and re-installed the brace with a whole 1mm clearance. The water temperature gauge I ended up simply putting outside the thermostat for now, figuring when I do a coolant re-route I can either move it or add a second gauge for the back of the engine then. Had a few gremlins with a mis-marked oil pressure sender (positive was marked negative ...) and what eventually turned out to be a length of wire which a break in it for the water temp send... I'll post pictures when I get a chance but my ISP recent closed their photo gallery where all my pictures were hosted so will have to wait. Also put my new alloy tow hooks on from Mitchf1's group buy today. My factory rear tow-hook was too thick to use the provided bolts but luckily I have a large pool of parts to go fish bits out of so got it installed fine.

Now the long journey of configuring the DL1 starts which has sooooooo many options..... Right now it's only got a tach signal and GPS antennae hooked up to it but should be enlightening when I get it on the track. The 20hz GPS is pointing out just how bad my speedo is with the 215/40/17's and 4.1 diff o_0. Though strangely it's tacho response is WAY too slow for my engine when it's blipped.

[Hellmun]

One other update of note... won't be doing the 300 this year. I really want to put more money towards my turbo conversion and Andrew wants to finish his car off.... plus both of us are out of tyres, entry went up...so we're looking at over $2000 each minimum and them moving it to July instead of November this year hurts. I have both cars due for Rego in June

[Guran]

A year since the last post. Must be time for another update! How's the turbo build going?

[Hellmun]

It is imminent, the NB8A motor I bought has already been stripped, bores honed and reassembly has begun. The forged bottom end has already been balanced, that's why I couldn't run my car at the clubday as the clutch/flywheel off the current engine were in the machine shop. I drop the car off to Daniel Deckers in approximately 2 weeks to install the motor, fuel system upgrade, intercool piping, new exhaust...etc. There's a long list of parts but fingers crossed the motor will be absolutely bullet proof. Now I just need to find a few spare 6 speed's.....