Jump to content

Truenotch's-Old-Man's MX5 - MX5RacingNZ


Truenotch

Recommended Posts

2 hours ago, Vintage Grumble said:

Window net, but no roof? Wat? Puhuhuhu

I know. The rules are that we have to have window nets, but it would be easy for an arm to go vertical in a big rollover. I like having the roof open for an easy escape after a big crash. 

Just now, anglia4 said:

Whats it cost you to run a season roughly??

It's pretty cheap to run for a season. The current set of tyres has done around 8-10 rounds of racing, plus a bit of testing and they're ready for replacement (although the pace was fine at the last round). Brake pads last at least a season too. Fuel is 20-30L for qualifying and 3 x 6 lap races. 

So for a winter series at Manfeild the costs probably look like this: 

  • Entry fees ~ $900 for 4 rounds including transponder hire
  • Tyres - $800 per season if you stretch them out for two seasons
  • Brakes - $500 per season? 
  • Fluids - $200 per season 
  • Fuel ~ $250 (120L of BP 98)

$2650 per season seems about right to me. They're one of the cheapest cars to run. 

Just now, 00quattro00 said:

Are they faster with the roof on?

Probably. I haven't tested back to back with the roof on/off. We kept it as a no-roof class to keep costs down and so the tall guys could build higher roll cages. Hard tops are going for $1500+ these days. 

  • Like 1
  • Thanks 2
Link to comment
Share on other sites

  • 5 months later...
  • Replies 191
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

  • 1 year later...

Next up was the first round of the 2022 winter series. We'd stripped all the stickers off the car between seasons with the intention of getting it painted. It didn't quite happen for a couple of reasons, so the car went to round 1 with makeshift stickers instead. 

FB_IMG_1654477482499.jpg.513039c731691c7b5ee39b72ec7c009b.jpg

FB_IMG_1654477467697.jpg.6ca093d6cdd3e6173d11e5303d22ee01.jpg

We had 20 cars at the first round which was awesome! It's a whole different game in the reverse grid races with up to 19 cars ahead of you and only 6 laps to get to the front!

Here's some footage from the shortened race 3. This was shortened to 5 laps as we were running out of daylight. I was able to make it from near the back through to 8th.

The golden hour made for some nice photos like the thumbnail above. The tight competition made it super close at the front! I ended the weekend 3rd in the points. 

FB_IMG_1654477467697.jpg.6ca093d6cdd3e6173d11e5303d22ee01.jpg

We got the car home and stripped it back to head to the paint shop. 

20220606_142347.thumb.jpg.fd75c37aec8323d878a8e9d61e42f438.jpg

received_342833331299160.thumb.jpeg.a3cfce57ffcfd6b8318f1e0f51aa859f.jpeg

received_1215856589227302.thumb.jpeg.25285cc722da37d7f051d6e7a10d5d72.jpeg

Ooh, shiny!!

received_322019140128561.thumb.jpeg.fb3e80736b1f74708cd475ba3b8f7f41.jpeg

Round 2 came up pretty quick, so we threw some impromptu numbers on again along with a new windscreen banner to promote our new series sponsor: Hankook Tyres. 

FB_IMG_1656936955577.jpg.f8143d0df105df281f7056ecc901a3ef.jpg

I qualified 1st at round 2, but unfortunately the meeting was cancelled after one of our drivers had a medical event during a race. This was a bit of a traumatic experience for the marshals and drivers. Thankfully the driver survived and will make a full recovery! 

The car looked weird without stripes, so I got @Chunky_t to draw up some #1s and produce a few stickers and stripes.

20220704_232328.thumb.jpg.1df4c1b498ce82ace00aa47dcbf7ad57.jpg

The next event was our mini enduro event "24 Minutes of Le Manfeild". The longer format races are quite different to our usual 6 lap sprints. We had to transit the pit lane twice in the race, which added a bunch of strategy to the race. 

Jack and I battled hard that day! In race two we were inseparable.

FB_IMG_1658737846427.jpg.49efac9e151fce11846e252cd604f256.jpg

Jack edited footage together from our two cars to show the battle: 

This past weekend was round 3 of the series and we had 20 cars again! We expected around 23 as we had a few new drivers, but we lost a couple to sickness. They'll be back for round 4 along with a few others, so we might see a grid of 25+ this season!

FB_IMG_1660037652326.jpg.60aed691c760c0caf42d6c3390f852f0.jpg

Added a couple more sponsor stickers this time too. 

FB_IMG_1660037635381.jpg.23572ed86eabf00182050f1557e3586e.jpg

Screenshot_20220809-142003_Facebook.jpg.ce02dea252f26b27fe1c288038d253be.jpg

Yet again, big grids made for great racing! And the reverse grids were challenging again. Race two was my best - I started 17th and finished 3rd.

 There's one round to go and it's going to be a big one! We're running a two day festival with extra classes and special cars on display. 

If anyone's keen, we'll be running classic car displays on Saturday September 3rd and every car in the show will get a free cruise session around the track. 

  • Like 8
Link to comment
Share on other sites

  • 7 months later...

The September round of Winter Series was next up and we had a huge celebration for the Manawatu Car Club's 75th anniversary. We made a push to get as many entrants as possible - it ended up being the biggest winter series meeting we've ever run! I had the AE86 and the MX5 out, so was busy all weekend. We also produced some memorabilia for the event: a cartoon poster of Manfeild and a bunch of cartoon car stickers for the kids (and the big kids...)

20220901_210256.jpg.a9514931c7c85bd409335706072ab0a0.jpg

The day started off reasonably good. I was still in the hunt for the championship and qualified in 4th with a few fast drivers in front of me. We were all set to go for race one and disaster struck! The mystery ignition fault from round 1 returned (it caused me to miss qualifying at round 1). I was a DNS for race 1 and had to start off the back for race two. Ouch! 

Starting off the back was great fun though. We had a 26 car field. The biggest field we've ever had! I manage to make my way up from 26th to 7th by the end of the 6 lap race. 

received_357537699810975.jpeg.820337cf46045952ae69fe3b8f037048.jpeg

For the final handicap race of the series I started near the back with quite a big gap to the slower cars and made my way up to 11th. It was another busy race and was exciting as always! 

FB_IMG_1663149243990.jpg.cdee73a62cd6895d9ec944463b93337d.jpg

So that was the series over. I was absolutely stoked with the number of cars and drivers that raced with us during the 2022 winter series. We had 29 drivers enter at least one round of the series and the racing was close but clean. 

My electrical gremlin meant I was off the podium for the series, ending up in 5th place after missing qualifying and having one DNS. If not for those two mishaps, I would have been on the podium and in the fight for first place.... And I didn't get a single race win this season, so went hungry at each round without getting a chocolate fish :lol: . That'll teach me for running a #1 on the door! 

All niggles aside, the fact the series came down to such a close finish is great for the class! The top 6 cars were separated by just over 100 points. A few different results and the whole order would have had a big shuffle. It's exciting to see the series coming to life and there's a constant flow of fresh enquiries about racing with us. I'm predicting a big field for the 2023 Winter Series :D

image.png.49260c008858ef8f981d296a8c2d5009.png

 

  • Like 6
Link to comment
Share on other sites

Onwards to summer! 

For the start of the 2023 summer series we had an opportunity we couldn't turn down: supporting the Toyota Racing Series with live coverage on Sky Sport and TV3! We assembled 16 MX5s and turned up to Manfeild to kick off the season. 

FB_IMG_1675244856651.jpg.09a5d2b68467d81445ed2e4c2f267077.jpg

I reverted the car back to its original number and Dad gave the brakes a birthday. 

unnamed(1).thumb.jpg.fa61da05465c68dd8d8b59b58ce1416e.jpg

Qualifying was greasy and I wasn't on the pace in the wet. I ended up qualifying third, about .7 sec down on the leader. 

Race one I started 3rd and finished 3rd with some good battles along the way: 

FB_IMG_1675278833989.jpg.babe3dbd23ae0185316dac96933e05d7.jpg

Race two: reverse top 10. 

I started off P8 after finishing third in the previous race. It was busy throughout the race with lots of passing. At one stage the front 4 cars were 4 wide into turn 1! 

image.jpeg.3ca048957338f4ea4ea1f0c0dafe2568.jpeg

I chipped away and caught up to the back of the lead pack. Then Denis in #35 tried a bit too hard through the esses, made contact with Justin in the #84 and smashed his right front wheel to pieces! He almost collected me trying to take the hairpin with a flat tyre. I did what I could to chase down the frontrunners and made a lunge for second place on the last lap, but didn't quite make it stick. That final push gave me the fastest lap of the race (1.24.8) about .4 faster than the next fastest car. It was on for race 3!

Still got on the podium for that race and had a quick interview for Sky TV! (I know... famous) 

received_1852858398393979.jpeg.3d0f73bf185a4fa106aa7c978be16bf3.jpeg

Race 3. Sunday afternoon. The scenes were set and our race was being broadcast live on TV3. We all had friends and family tuned in around the country and I was starting from P3 with the knowledge that I had the car pace to beat the two cars ahead of me. 

The car had been running faultlessly all weekend, so we lined up on the dummy grid ready to rumble: 

received_934578187919241.jpeg.d7864778d94196db6327cd556afeea71.jpeg

Aaaaand, my mystery ignition fault came back! So I didn't make it to the start :doubt:

received_1237501600170520.jpeg.87f865ab510f4360bc5967b7516473e0.jpeg

So that was my round 1 over. I took home two third place finishes, so banked a few points, but was absolutely gutted to miss the chance to be on TV3! But hey, that's racing sometimes. 

I took the car home and jumped straight into diagnosis mode. When the fault kicked in I could only get up to a maximum of about 100kph and it got there super slowly... I knew it was a spark issue and felt like something was limiting the timing over about 25% throttle position. We threw a timing light across it to confirm this and went to work trying to find the culprit. 

Since the winter series we had replaced the spark plugs, leads, tested another set of coils and replaced the ignitor pack, so I was confident it wasn't any of those. 

After a bunch of poking and prodding, I had a look at the external ECU kill switch and found it was rusty as! So I bridged around the switch and the car came back to it's normal crisp self. Problem solved!!! 

.... Or so we thought... 

received_8762141800494969.jpeg.f9348c0c998d1a76c172144a57aa005c.jpeg

  • Like 5
Link to comment
Share on other sites

Round two came around quickly and we headed off to Taupo International Motorsport Park for another round with Super Sprint NZ and the Toyota Racing Series. 

This time we were back to our traditional summer series format where we run off the back of the Mazda Racing Series. The RX8 class has grown hugely over the last few years, so we ended up with 11 MX5s and 28 RX8s running together. It was busy out on track! 

I ran the car in testing on Friday and it seemed to be going fine, but after the first hot run I started it up again and the mystery electrical fault had returned. It only seems to be a problem when the car has been running (or left with the key in the on position) for a while and then re-started while hot. The fault wouldn't show up if the car was left to cool off for a couple of hours and re-started. Once it was running it would stay fine as long as it wasn't turned off again, so the solution for this round was to leave the car alone between races and only start it pre-race without turning it off again! 

Nick Cummings showed his pace early by qualifying on pole. The combination of his driving style and car setup was obviously working well! His time was 1.4 seconds quicker than my 2nd place effort and it was his first time racing an MX5 at this track. Impressive! 

We had a good camp of MX5 racers and were the only drivers with no pit crew at the event, so we all had to pitch in to help each other if anything went wrong.20230211_092752.jpg.149bed96e1ad46a871801c9be1636fb5.jpg

Race one was busy off the start! We ended up tussling with the back of the RX8 pack in the first lap and I dropped back a few places. I put my eyes forward and picked a few back off. Once the dust settled I was the 2nd MX5 on track behind Nick in the grey #3. 

Race two, reverse top 10. It was busy off the start again I started from P9 and the first couple of corners were intense! Managed to keep my nose clean and progressed through the pack up to 2nd place again. Nick made some good moves through traffic and ended up with a decent lead! 

Race 3 is where the action happened. Nick started from pole, I was in 2nd and we were having a close race for the first couple of laps. Then a few RX8s had a crash up ahead and Nick chose the wrong side of the track through turn 5. He was on a huge patch of oil and ended up drilling an injured RX8 in the rear bumper.

Here's a quick clip from the TV coverage: 

 

That opened the door for me to take the lead of the MX5 class and bank 75 points for the final race. It's not how I wanted to get a win, but I'll take it. 

 In the winners circle: 

20230212_140428.jpg.26151a4e0e0e0e2036962bacaa9b8551.jpg

Nick's car had bent the horns on the front of the chassis and was looking pretty sad after the race: 

20230212_141442.jpg.9ddaef88a919c8a990cc5c37213f1ff9.jpg

Race 3 in car: 

 

  • Like 3
Link to comment
Share on other sites

  • 1 month later...

Between rounds, I was thinking about ways to make the car more stable.  It's always been fairly balanced, but I'd noticed more understeer and unsettled characteristics since we changed to the lower grip tyres, especially in the wet. 

My initial thoughts were that my chosen spring rates are too high. I've roughly based my rates off some USA based advice and it handled great on the old Toyo R888Rs (if not a little bit understeery at the limit). Everyone else in the class runs ~500lb front at ~300lb rear. I run ~700lb front and ~400lb rear (high spring rates in the front to keep the inside rear wheel on the ground, cause these cars love to jack up). The springs in this car are only 6" long, so getting replacements in NZ is a pain in the ass, otherwise I would have bought a pair 550s or 600s to test in the front already, but I got thinking about what else had changed. 

Then I remembered the bump stops. 

Remember these guys? (You probably don't). They're MX5 specific race bump stops and are designed to give a rising spring rate instead of harshly hitting a piece of rubber. They're 36mm long and ramp up from ~300lb/in to infinity over the space of ~25mm compression. I'd based my shock lengths off the ~10mm compressed length of the bump stop, but hadn't actually measured how much travel was left before they came into play. So I jumped under the car a few weeks ago and stuck my finger between the springs... Yep, as I suspected, there wasn't much shock travel before the bump stop made contact (1 fingertip, to be precise). 

ScreenShot2023-05-22at10_38_31PM.png.552e601f83c6975beac1c68e2feaaadf.png

Another change with the new tyres is the lower rolling diameter, since they're a 195/50/15 road tyre instead of a 205/50/15 race semi slick. This means I now have more compression travel available before the tyre hits the inner wheel well (common in MX5s). 

So I whipped the springs and bump stops out and jacked the wheel up as far as it would go, took some measurements and figured out roughly how much I could take off. 

20230430_170525.jpeg.8d413a7e9d39d2c819d4e36b538d695c.jpeg

20230430_180532.jpeg.27a73f1726591b5cd9c780f4e391a650.jpeg

... I'd love to be able to run this car with no springs... 

I gave the bumps a careful 10mm trim, making sure to leave at least one "bellow" complete so it would still have nice compression characteristics.

20230430_183303.jpeg.efb6f614f1f4bf804ac09ed0a7679aa5.jpeg

10mm doesn't seem like much, but on an MX5, the motion ratio for wheel travel to shock travel is around .66/.73 Front/Rear, so that 10mm trim gets me ~15mm of extra wheel travel before the bump touches. It should make a difference!

I also worked out that the front pinch welds will end up at around 45mm off the deck at full compression. I wonder what might scrape if it ever gets there? :lol: 

  • Like 5
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...