Peters NA6 "Britney"

[OurCognitiveSurplus]

Enjoying reading this thread. I'm hoping to get into the SDMA Hill Climbs in 2012, might see you and Jaffa there. Also good to read stories about Carco, I always think about getting dave to do some various work on the car, but always get caught up by indecision.

[PeterB]

"Jaffa" returned home unscathed again after an another well run track day.

I left half my clip-in harness at home so had to run with my lap sash belt - you don't realise how much you rely on the Sparco/Harness to keep you located, particularly under brakes.

The R888s were pretty worn so I reversed then on the rims and swapped them side to side to extend their life (as the left side do all the work), one advantage of the R888.

However, in the morning I could not get any grip and was over a second off my usual pace. I found it slippery, but particularly the transition from grip to slip was unpredictable and the transition back even more so, so almost got caught out a couple of times - unusual as the R888s usually give pretty good feel of what they are doing.
Maybe reversing and swapping the tyres required them to bed in again.

The day started wet, with water running through the fishhook, until traffic cleared it. The best I could do in the morning was 1.15.6

Things improved after lunch and I managed to get down to a 14.8, then I think a 14.65 on my last lap, which is just 1/10 off my best, so was very happy given the conditions, and was the quickest type 5M on the day.

Jaffa ran faultlessly, but the clutch felt a little soft, so I will fit a new slave cylinder and braided clutch line over Xmas.

Now to renew my CAMS license and the long wait until the next track day.

[mitch_f1]

I'm pretty sure I was talking to you on the dummy grid before one of the sessions(I was in the blue NA)? If so, nice car, and nice to meet you

[PeterB]

Yep that was me. Catch you at the next track day.

[PeterB]

Am doing a spanner check and fluid change in preparation for the Feb track day.

I replaced the clutch master and slave cylinders and fitted a braided clutch line to replace the convoluted standard line. Hoping this will give much better clutch feel.

Checked the brake lines and they looked pretty old and dodgy so I have replaced all 4 with braided lines from Carco and will flush the system with new fluid. Hopefully this will give a better feel, but more importantly give me the reassurance each time I do a big stop.

Otherwise the car seems fine, so ready and ready for the track day. See you there.

[PeterB]

February 19 track day done and run. The brakes felt good with the new braided lines, so that was a success.

The day was unexpectedly hot and dry but that does not explain why I was 1 second off my best.

I struggled to get my usual times all day and ended up with a best of 1.15.56 (after a 1.15.8 on my very first lap) and was beaten by Stewart in the Commodore ute. In the afternoon I was doing consistent mid 15s, but couldn't get anywhere near a 14, the first track day for a while I haven't achieved this.

I couldn't find any one good excuse, so must have been a combination of things - too hot, tyres getting old as they felt pretty slippery, driver getting old and fat, down a little on power (but maybe because I did a training run in an NC).

However, despite the times I had great fun day leading/chasing various cars, including an Evo and WRX across the top - couldn't get near them in the straight bits, but could wheel them in across the top.

Once again an excellently run event, with plenty of runs considering the large field. Thanks to all the officials, particularly those standing in the hot sun.

[PeterB]

Sunday 1 April 2012 was the first state supersprint round.

It started as a very hot day and I could not get below 1.15, but a cool chage came in after lunch and times dropped quickly - shows how much effect the weather has.

I managed a best of 1.14.66 so just off my pb with aging Toyo R888 tyres so very happy.

Jaffa ran like a dream again.

[PeterB]

Ran the Fairbairn Park Hillclimb in Canberra today (29 April 2012) - a cool but sunny day.

First run ended with me backwards off the track on about the 4th corner - not a good start and a good add for having one sighting run - the trouble with no warm-up or practice runs.

My Toyo R888s have now run about 9 track days and 3 hillclimbs in 12 months, as well as being dríven to and from the track, and have just about had it - but I think a pretty good run for tyres that get a pretty good flogging.

My best for the day was a 51.48 which is almost a second off my pb as I could not get tyre temperature in the old tyres, but was still up with the quickest MX5s (there were 6 entrants running MX5s). Still a fun and cheapish day, but only 5 or 6 competitive runs of 51 seconds each does not compare with 25 or 30 competitve laps at a track day

Looks like time for new tyres before the June track day - Do i go for the cheaper R888s again or bite the bullet and pay up for Kumho V70A, Bridgestone Re55 or the new Yokohama A050 which all sound like they are quicker ?

[PeterB]

So after starting with a tired and damaged 1989 NA6 the car specifications are now :

CARCO rebuilt 1600 with original bore, pistons and cams. Head is shaved and has cleaned up ports.
Running 12 degrees advance on 98 ulp as compression is unknown.
Dynotune A.C.T. dyno showed only 65rwk (but is known to be pessimistic).
New water pump, cam belt, hoses and plug leads.
New alternator.
NA6 standard exhaust system (needs upgrading).
DDMWorks pod filter with heat shield from Rspeed (replaces stock air box).
NA6 standard radiator with plastic panel to help airflow.
1800 clutch.
NA6 5-speed with new gearshift kit fitted.
Torsen 2 lsd with 4.3:1 ratio, NB driveshafts and tail shaft (ex NB automatic via MX5 Mania).
New rear wheel bearings and drive shafts rebuilt.
NB KYB AGX adjustable shocks with Ground Effect springs (375 lb front and 250 lb rear).
Camber : front -2.2, rear -1.8 with maximum caster at front.
Red (?) aftermarket swaybars (rear adjustable).
Carco front swaybar brace (to stop mounts cracking again).
Mania front and rear underbody braces
Slotted front NA disks with Hawk HP+ pads (great on the track, but noisy and dusty on the road).
Stock rear 1600 disks and Lucas pads.
NA lined hard top with demister (soft top removed as damaged).
Full interior trim with cheap Kenwood stereo.
NB Brown-Davis steel roll over protection system (can be CAMS approved) with padding.
Sparco Sprint drivers seat on re-drilled NA seat rails.
Monza 3" 6-point clip-in harness.
Drift flat bottom steering wheel (same bolt pattern as original Momo) - to better clear long legs !
15x6.5" rims with Toyo R888 GG semi-slicks 205x50x15 running at 32-33 psi hot for track.
NB8A 15"x6" with Pirelli road tyres for street use.
Rspeed OEM style front lip (rear lip not yet fitted).

Jaffa has been built for use, not looks and could do with a respray, but in just over 18 months I have run twelve Wakefield Park track days/supersprints with a best of 1.14.6 and won class 5M for 2010/11, one driver training day at Marulan, six Canberra hillclimbs with a best of 50.5 and plenty of road time so I am a happy MX5er.

[OurCognitiveSurplus]

Shame I didn't catch up with you in the hill climb - were you the red NA with the panda back end? I was the dark-blue NB struggling in the 53 seconds.

Are you under 1600cc type 3?

[PeterB]

Hi, Peter Browning running the red NA6 with red hardtop, number 32 for the day, on Toyo R888 semi-slicks. I went past your car a few times, but our paths didn't cross unfortunately.

Tom Ballard (trashpack) was running the other red NA6 with the top down and no roll-bar, which is also a 1600, running on Federal 595-R tyres.

My NA6 is a rebuilt 1600 and I have to run as type 3A at the hillclimb because the ports in the head have been cleaned up - as soon as you remove any metal from the head/ports you go into type 3 for the hillclimb, although it is only type 2A for NSW state supersprints.

The semi-slicks make a big difference to times, even when old - my best in this car when the semi's were fresh was 50.5 compared to a low 52 on Kumho KU36. The Torsen diff also helps with the launches.

Tom and I have been running the hillclimb since the 1980s, so have had just a little practice in getting around the place. It is hard to get a rythym at the hillclimb as you have so few runs compared to a circuit where you get plenty of laps in a day to get your eye in.

Most people I know were about 0.5 seconds off their best on Sunday due to the coolish day.

May see you there next hillclimb.

[PeterB]

Fitted a new set of Hawk HP+ front brake pads and 4 new Toyo R888s 205x50x15 from Taleb Tyres ($210 ea fitted).

Tried to bed the pads and tyres in on the road and drove Canberra to Goulburn on them, but they still needed more bedding in on the track.

Sunday 3 June was a state supersprint round at Wakefield Park. The track started wet and didn't totally dry, so I was happy with a 1.15.12 and 2nd in type 3A. The tyres took a couple of runs to get some grip, but then started to come on.
I had lots of fun chasing a VN V6 commodore which did a 1.15.17 on semi-slicks and just keeping ahead of Stewart T in his NB.

The usual excellently run MX5 supersprint, given the lousy weather - thanks all.

Monday 4 June MX5 track day started with a cold, but dry track. Expecting rain I decided to have a full on go from the start as I was well dialled in from Sunday. My first flying lap was a 1.16.2 so it was looking good for a quick day. However, I soon ran up on traffic as others were feeling their way, so I dropped back but muffed a gear change, so lap one was the only clear lap.

I then got a message that I had to dash back to Canberra as Helen was ill (all ok now after a day in casualty), so that was the end of my day.

Luckily the 1.16.2 proved to be the best in class 5M for the day, as I suspect most of the others were on road tyres.

Sounds like others had a good day, so sorry I missed it as I was hoping for a pb on the new tyres and with a days practice - can't be helped.

[Guran]

Sorry to hear about your early departure on Monday but it's a relief that Helen is OK.

You managed those new R888s much better than me. What's your secret?

[PeterB]

Bryan

Our driving styles on Sunday were similar, I was probably not throwing it around as much, so there may be two differences.

I am running 2.2 degrees neg on the front and 1.8 neg at the back with springs and bars so maybe the tyres are better planted and build up a more consistent temperature on a cold track, compared to the performance of a more road spec. I run 32 psi hot.

Bedding in - I ran the R888s on a twisty section of road for about 15 km when I first fitted them - say 3 km quick then a short cool down and so on. Not as good as bedding in on the track, but seemed to scrub them in. Then I drove to Goulburn on them up a back road for another 100 km and drove them to the track so they had some core temperature before the day started. I used the first couple of sessions to bed in a bit more before really getting into it. On Sunday I had no graining and had plenty of grip by days end - I think without the water I would have been around my pb.

However on Monday I got fully into it from lap 1, without any real warm-up, and the left hand rear did show similar graining to yours. The front did not grain up, but the car was walking around in the rear a lot.

I wonder if the issue with fresh tyres on a cold day is that the surface rubber gets hot quickly, but if the tyre does not get any real temperature into the core of the tyre the surface rubber grains up.

Maybe a run up Macquarie Pass or Jamberoo alternately getting some real heat in the tyres, then having a cool down, may bring the tyres in better. We may also need to allow a bit more warm up time on a wet track to really bring them in?

[PeterB]

After Monday, I discovered the downside of failing to warm-up tyres and brakes properly before having a full-on run.

For session 1 of Monday's MX5 trackday I knew I only had one shot at it ( I had been advised I probably had to run home straight after the session) so I attacked full on from lap1 to at least set a time.

I only did a half lap warm up of tyres and no real warm up of brakes and Lap 1 was a 1.16.2 in cool conditions so was pretty well committed.

As mentioned elsewhere, the LHR Toyo R888 grained up (as had Bryans) due to excess surface heat and no core temperature, but this should not be a lasting issue.

However, the front brakes, which were near new Hawk HP+ pads on used slotted rotors, had no temperature and, although being bedded in on the road and run at the Sunday supersprint, they glazed so badly the car was was almost undrivable - the front brakes felt and sounded like a grinding wheel. The surface of the front pads had melted onto the rotors, coating them in a black film of burnt pad material - the outsides were the worst.

An attempt to clean them up by repeating the bedding in process just made them worse and as they were slotted rotors I could not get them machined locally, so I reverted to the backyard method of a flappy disk on an angle grinder to cut them back to good metal. It took a lenghty period of grinding to get them back to metal again (done on a hub so I could spin them while grinding to try to keep them round). I also skimmed the surface of the pads to get rid of the glazing on them.

I have bedded them in again on the road and they feel as they have recovered - I will give them a good run on a country road to see if I have saved them.

Note to self - on a cold/damp day thoroughly warm brakes and semi-slicks before doing a competitive lap.