Peters NA6 "Britney"

[PeterB]

My latest project is a damaged NA6 to be built up as a budget road registered track day car.

My first car was a red NA6 with turbo, koni/kings/whiteline suspension and mazdaspeed lsd. A great car but I was unable to run state supersprint rounds due to the low height of the Brown Davis roll-bar. After being refused entry to an event I needed to find an alternative.

This is when Fanta arrived from Brian Anderson as a rolling chassis and all the good bits from the road car were swapped across to build up a type 4 supersprint/hillclimb race car. I started with the turbo setup, but after lots of problems with under bonnet heat and broken manifolds I went back to normally aspirated.
Fanta ended up with a stock 1600 bottom end with a good head, cams and Autronic SMC computer for 93RWK. The Koni/Kings/Whiteline suspension and 1600 mazdaspeed lsd was swapped across and Brian's willwood brake setup and 15x8"rims were used with slicks or Kumho V70A.
Fanta holds the type 4 under 1600 state supersprint class records at Eastern Creek, Oran Park and Wakefield Park circuits and Fairbairn Park hillclimb. Wakefield Park was 1.09.25 on slicks and 1.10 on semi-slicks making it a pretty quick 1600, even as a lightened race car (about 820kg).
Despite Fanta being great fun to drive and having some great dices with Mark Hellmund, after the closure of Oran Park and a trial sea change by us, Fanta went to live with Travis in Sydney.

A green NB8A joined the family as a street car - on the promise it would not be raced or modified !!

After an evening at Carco over a few beers, a damaged NA somehow ended up in my driveway - I am still not sure how -
and it is being built up as a budget road registered track day car.

Following the orange Fanta, a red NA with a red hardtop was quickly christened the Jaffa.

I am going to have to get used to going a lot slower than with Fanta, but at least I have a windscreen and roof - a definite advantage at Goulburn..

[PeterB]

The first task was road registration in Canberra, so after several visits to the Carco spare parts bin and the frequent use of race tape, self tappers and stickers to cover obvious paint flaws, registration was achieved and PB-777 was released on the world.

Plan A was to run as an unmodified NA 1600, but as inspection of Jaffa revealed aftermarket springs (Pedders ?) and sway bars and the absence of bits of trim, etc I decided it was too hard to go back to standard, so the build of a modified NA6 1600 commenced.

The first serious run of the car filled the street with oil smoke, so an engine was required. Russell from Carco re-built the original motor. As the bores were good, a hone and rings, bearings, gaskets, water pump and cambelt were sufficient to get us mobile.
A forum ad for a modified 1600 head resulted in a replacement head that has had the ports cleaned up and surface ground a bit - premium fuel is run as a precaution as compression is a mystery. Standard inlet and exhaust systems are still in place, so the real benefit of the head is not yet being achieved, although it does feel that it has potential.

A 2nd hand 1800 flywheel and pressure plate were fitted with a new clutch plate - plenty of grip for the planed horsepower.

The gearbox input shaft was screaming, so a low km NA6 gearbox from MX5plus was also fitted.

The tyres on the car were rubbish, so Carco supplied a set of Aray 16x6.5"rims fitted with Kumho KU36 205x50x15".

So off to a trackday to see what we had.

[PeterB]

Trackday 1 was the October run, which was an excellent day with lots of grip, so Jaffa could show its best.

We had :
1600 with cleaned up ports in the head, but standard exhaust and air intake - running on Caltex 98 ulp.
1800 clutch, NA6 5-speed
Open 1600 diff
Pedders springs and swaybars
Stock 1600 disks and pads
Soft top.
16x5.5" rims with fresh 205x50x15 Kumho KU36.

By session 3 Jaffa was down to 1.16.5, with a best of 1.16.28 in the final session.

A very satisfying result and Jaffa was showing real potential, but it showed up the need for a good wheel alignment as Jaffa was understeering a lot, the stock brakes were cooked and I was having gear selection problems (2nd to 3rd after the fishhook).

[PeterB]

The mechanical problems were fixed by :

Dba front slotted rotors (NA diameter) and Hawk HP+ pads
New rear standard rotors with fresh pads
Gear selector bushes and cover - transformed the gear shift and it feels like new.

Wheel align - could only get 1.8 degrees negative front and rear.

Off to the December track day ready for a big improvement.

The brakes felt much better and were consistent throughout the day, so a worthwhile improvement.
Similarly the gearchange was great - a huge improvement.
Jaffa was still understeering, so the suspension needed revisiting.

However, it was a lousy day and I ended up with a best of 1.17.15. Everyone seemed to be up to a second of the pace, so only a slight improvement, but Jaffa was much more driveable. The dissappointment was I was second in class by only .01 (to 1.17.14) so should not have had a hamburger for lunch.

The moral is don't change your car - only drive on good, sticky days.

[PeterB]

So has it been a success to date - the biggest issue was can you go back from a competitive (trailer only) race car to a reasonably lively road car and still get the same fun from driving it.

The answer is a definite YES.

Thanks to Carco I now have a fairly cheap, road registered 1989 NA6 that is a bit rough to look at (needs a respray and rear window) but has a fresh motor, clutch, brakes, low km gearbox and new rims and tyres which can run 1.16 at Wakefield Park and 52.0 at the Canberra hillclimb, so it has to be one of the best value club motorsport cars you could get, as well as being a great fun road car.

My son and I agree it is as difficult and as much fun to drive as Fanta, with the bonus of regular runs up the highway. Running in this time bracket there are many more similar cars out there to chase around, adding to the challenge.

So does common sense cut in and should I continue to run Jaffa as is and just have fun without any further outlay - of course NOT.

[Guran]

Great thread Peter! I'm really looking forward to reading more about Jaffa's development (tip: go the LSD next). It does break my heart a bit to learn that you came close (but not close enough) to competing in standard NA! I'd love to be running against you. It's great competing against Hammer, but tough to beat a Clubman with more kWs, TorSen LSD, Bilsteins, more bracing, etc. I also have the hope that Phil Lea, Phil Christie, etc will stick around in standard NA and improve their pace with more practice.

[Jeo]

Nice write up so far Peter. Keen to see what else you've got in store for it.

Playing at the hill climb this weekend?

[PeterB]

It would have been good to run a stock NA, as it still amazes me how quick they are.

Yes I will give the hillclimb a go this Sunday.

After the December track day I checked the suspension and found the right rear was seizing or had too little travel - it was low and too stiff on the Pedders springs.

I tried for Yellowspeed road spec coilovers but none were in stock. I have been loaned some KYB AGX adjustable shocks with Ground Effect coilovers to try. I replaced the rear upper outer bushes whilst fitting them.

We could only get 1.6 degrees negative at a good ride height, so will need to consider offset bushes.

To improve my chances of qualifying for the old and bold award I also fitted a Brown-Davis roll bar (NB type) and clip in harness.

I then ran the February track day and at the risk to my ego also gave my son a run.

February was another slow day and I managed only 1.17.02, with John getting down to 1.16.6. (my time sheets shows one 1.15.8 which looks like an aberration).

So even with the better shocks and brakes, the weather kept us slower than my first run in the car - frustrating ??

The brakes are a definite inprovement with slightly better, but much more consistent stopping.
The coilovers did not show a great improvement over the stiff pedders, probably due to insufficient camber.

Wheelspin through the fishhook reinforces the need for a lsd.

So slow, but definite improvements.

I was happy with the Kumho KU36 as a performance street tyre with consistent and predictable wet and dry handling.

[PeterB]

After the February track day the rear end was howling for mercy, so both rear wheel bearings were replaced.

The diff still didn't seen happy, so a 1600 viscous diff was purchased for $200 off ebay and fitted.

As the Canberra winter was approaching fast and my plastic window was torn, I purchased a lined, rear demister hard top. This will suit the NA and NB. I run the NA with the hardtop fitted and the damaged softtop removed.

Co-incidentally a tyre on the NB was damaged last month, so I fitted the Aray 6.5" rims with the Kumho KU36. These suited the NB perfectly so we decided to leave them on the NB.

With the May trackday approaching I looked at tyre options. My preference was to go semi-slicks and Kumho V70A medium would have been my preference - until I got quoted the prices of around $330 for a 205x50x15.

After ringing around I got a quote of $225 for Toyo R888 GG (medium) compund 205x50x15 from Taleb tyres in Sydney. I finally got four R888s, fitted to new 6.5x15" rims (a bit heavy, but OK) with wheel nuts delivered to my door within 24 hours for $1,300, so I grabbed them.

So off to the May trackday to try them out, with the following setup.

JAFFA - 1989 Red NA with hardtop

Carco rebuilt 1600 with cleaned up ports -
12 degrees advance, running on Caltex 98 ulp as compression unknown
standard exhaust system
standard air intake
standard radiator
1800 clutch
NA6 5-speed
Viscous 1600 diff - {not much use at Wakefield - is it working?}
KYB AGX adjustable shocks with Ground Effect springs (375 lb front and 250 lb rear)
-1.6 camber front, -1.8 camber rear - needs more!!
Red ? swaybars (rear adjustable)
Slotted front NA disks with Hawk HP+ pads
Stock rear 1600 disks and pads
NA lined hard top (soft top removed)
Full interior trim
16x5.5" rims with Toyo R888 GG semi-slicks 205x50x15.

The May trackday was cold but dry, and on the R888s Jaffa was running consistent high 1.15s, with a best on the day of 1.15.52.

I am very happy with the performance of Jaffa and a good day will see quicker times. Interestingly I was chasing Allan Rewell in his NA and whilst I was quicker over the top due to tyres, the cars were identical up the straight and his is a stock 1600, so my head can't be working well and needs a better intake/exhaust (seems logical).

The viscous diff may have helped a bit, but I was still getting wheelspin, so a better diff would be preferable.
The R888s were grippy and consistent, but needed a lot more temperature to be at their best. They are supposed to be 1/2 second behind V70As or Dunlop D03s, but seem an affordable compromise and are hard enough to drive to the circuit on (treadware rating of 100).
I definitely need another degree negative to make the R888s work, so off to Carco for some offset bushes.

Although the budget has increased a bit, most high cost items (hardtop, roll bar, wheels) are useable on the NB or readily sold if required, so I don't feel it is overcapitalised as yet.

Maybe the viscous diff will help with launches at the hillclimb ?

Still very happy with the Fun for Dollar value.

[PeterB]

In preparation for the hillclimb I thought a bit more chassis stiffness would help, so I fitted a pair of MX5Mania chassis braces front and rear. I can't really feel a difference, but they must help.

The Fairbairn Park hillclimb in Canberra is a fairly challenging track with both uphill and downhill sections. There are usually a number of MX5s running in various trim, including track day regulars Ian Vickers in his NB and Steve Green in his NB as well as several Canberra residents.

I still hold a club class record in Fanta at 48.0 seconds as type 4A, and Jaffa's best has been 52.06 on Kumho KU36s last year.

My first run with the Toyo R888s was a sighting lap to see how it felt, but easily achieved a low 52, so things were looking good.

For my 2nd run, I launched at around 3,800 rpm and bogged down a bit, but it was very grippy for a 50.65, which was then leading the class for type 3A. My opponent in a Sprinter then ran a 50.45 so I needed to pick up a bit.

For my 3rd run I tried a launch at about 4,400 rpm. It smoked up on the concrete start pad, but gripped when it hit the bitumen, when a very loud bang indicated the viscous 1600 diff was no more - very disappointing as the car had a fair bit left in her.

A borrowed car trailer got her home and I just finished re-fitting the original open diff. I opened up the viscous diff and there are lots of bits of metal in it, so not looking good.

So back to the drawing board re a lsd. I will run the open diff until the budget recovers from previous purchases and a dead water pump that had to be replaced in Helen's NB.

For those who haven't tried them, hillclimbs are good fun as it teaches a few things about launching a car and driving on cold tyres - you have to be fully on it in the first corner even though tyres are still cold, so is a good training ground.

[PeterB]

The viscous diff broke the spacer/washer that locates the pinion gear and I am unsure of other damage, so I will be running with the 1600 open diff until I can afford a good lsd.

To deal with the lack of turn-in, I have fitted offset bushes to the front inner on the front lower control arm. This will allow a reasonable camber setting and I have started with 2.2 degrees to see how it goes.

I also picked up a DDMWorks air intake thanks to the good aussie dollar - a heat shield and foam pod filter to replace the standard airbox. I did not go the Mania style intake as I did not want to cut the firewall into the scuttle area.

So we are now up to :

JAFFA - 1989 Red NA with hardtop

Carco rebuilt 1600 with cleaned up ports -
12 degrees advance, running on Caltex 98 ulp as compression unknown
NA standard exhaust system.
DDMWorks air intake (replaces stock air box).
NA standard radiator.
1800 clutch.
NA6 5-speed with new gearshift kit fitted.
NA open 1600 diff. New rear wheel bearings.
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 ? swaybars (rear adjustable).
Slotted front NA disks with Hawk HP+ pads.
Stock rear 1600 disks and pads.
NA lined hard top (soft top removed).
Full interior trim.
NB Brown-Davis steel roll over protection system (can be CAMS approved).
Monza 3" 4-point clip-in harness.
16x5.5" rims with Toyo R888 GG semi-slicks 205x50x15.

The next items to consider are an lsd, play with the suspension settings, better exhaust and maybe a front spoiler to pull in some more cool air and help with the front grip

All we need now is an event to run at.

[PeterB]

I ran the state supersprint at Wakefield Park on 19 June and had great fun watching Bryan in the rear view mirror - very entertaining to watch and his 1.15.7 was fanastic. Approx 100 competitive kms, so good value for money.

I had to abort the first run due to a misfire - a plug lead had come loose at the coil - an easy fix.

I managed to get down to a personal best of 1.15.08, but couldn't crack the 14s.

The extra camber helped considerably with turn in and I could place the car much more precisely.
I couldn't really pick a change from the pod filter, but I assume it must be helping at higher revs.
I was getting considerable wheelspin through the fish hook which was definitely costing time. It was noticeably worse that my last track day with a 1600 viscous diff, so the viscous is definitely a help.

I will try to repair the viscous dif for the July trackday and get into the 14s.

So we are now up to :

JAFFA - 1989 Red NA with hardtop

Carco rebuilt 1600 with cleaned up ports -
12 degrees advance, running on Caltex 98 ulp as compression unknown
NA standard exhaust system.
DDMWorks pod filter (replaces stock air box).
NA standard radiator.
1800 clutch.
NA6 5-speed with new gearshift kit fitted.
NA open 1600 diff (definitely need a lsd !!). New rear wheel bearings.
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 ? swaybars (rear adjustable).
Slotted front NA disks with Hawk HP+ pads.
Stock rear 1600 disks and Lucas pads.
NA lined hard top (soft top removed).
Full interior trim.
NB Brown-Davis steel roll over protection system (can be CAMS approved).
Monza 3" 4-point clip-in harness.
16x5.5" rims with Toyo R888 GG semi-slicks 205x50x15 running at 32-33 psi hot.

[PeterB]

To improve my seating position and to allow me to use a 6 point harness I am installing a Sparco Sprint seat. This will also give me some head protection from the B-D bar when driving on the road without a helmet.

Fitting is simple, just having to drill two new holes in the standard rails.

I will be using it on the street, so am leaving the standard seat belt in place as well as using the clip-in harness for track days. I am drilling the floor and fitting two eyelets with a backing plate for the crutch straps. The shoulder belts clip onto eyelets screwed into the brown davis bar (it is a NB type so has two threaded holes in the cross plate) and eyelets fitted to the standard lower seatbelt points (use a longer eyelet to go through the standard belt.

After blowing up the viscous 1600 diff and the original diff being noisy, I am looking at upgrading to a 4.3:1 torsen from a NB. Too much wheelspin at the fishhook and at the hillclimb, as well as should be able to lauch at the hillclimb without a problem.

Carco rebuilt 1600 with cleaned up ports -
12 degrees advance, running on 98 ulp as compression unknown
NA standard exhaust system.
DDMWorks pod filter (replaces stock air box).
NA standard radiator.
1800 clutch.
NA6 5-speed with new gearshift kit fitted.
NA open 1600 diff (definitely need a lsd !!). New rear wheel bearings.
To upgrade to Torsen2 4.3:1 (ex NB automatic).
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 ? 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.
NB Brown-Davis steel roll over protection system (can be CAMS approved).
Sparco Sprint drivers seat.
Monza 3" 6-point clip-in harness.
Drift flat bottom steering wheel (same bolt pattern as original Momo) - to better clear long legs !
16x5.5" rims with Toyo R888 GG semi-slicks 205x50x15 running at 32-33 psi hot.

[PeterB]

The Sparco Sprint seat and full harness is fitted. The seat seems comfortable and gives plenty of support. The seat was easily fitted by drilling two new holes in the standard seat rails - a very simple process.

The NB Torsen 2 diff 4.3:1 ratio is installed. The diff and tail shaft went in with no problems. The drive shafts were a different proposition as they were well and truly stuck in the hubs and closer inspection showed that the end of the drive shafts had been thumped with a big hammer, damaging the ends so a nut could not be fitted.

Three days soaking with penetrating fluid and the Carco hydraulic press finally got the drive shaft out of the hubs (thanks Dave). As the end of the drive shafts had to be repaired - ends ground so that they were round again and new slots cut - I also had them repacked and new boots fitted.

All now installed and seems good - hopefully goodbye to wheelspin and broken diffs.

I will have to get the car on a dyno to see if it falls under the 85 rkw for the new modified 1600 class.

[Guran]

Don't bother with the dyno Peter. I doubt Mike would bump you to Class 9, based on your times. Start doing 1:12s though, and he might think about it.