Advice - Endurance Racing Prep For 2+2

[mikmarda]

Hi Guys,

 

Long time no post. I was wondering what mods you have used to bullet proof your zed for long track days. 

 

I've gone through the car fairly thoroughly, however it is is bone stock (L28 with SUs, extractors etc, thermo fan, lightened flywheel, race pads, hilux callipers, 1" MC and a few suspension upgrades, elec fuel pump.

 

Things I have been considering to reduce changes of failure:

 - Diff Cooler

 - Additional temp switches

 - Additional Oil pressure/oil temp gauges

 - Baffles in the sump 

Any thoughts? Things to add to the list?

 

Additionally, what critical spares do you take to the track with you?

 

Finally what ratio Diff do you use for a circuit like Wakefield? I'll be there for a test and tune on the 24th August if anyone is keen to join

 

Cheers,

 

Mike M

[PZG302]

So are you actually looking at doing proper endurance racing like the Group S one hour race or the six hour relay type races, or just a track day where you might get six to ten 5 lap runs?

 

This will make a bi difference to what you need to do.

 

For track days of 5 lap sessions, just check fluids, hoses for condition. If gauges work, then for 5 laps no need to do anything else. If they don't work, replace with aftermarket gauges, but by the time it shows on the gauge you have probably broken it anyway, you will smell, see and feel most problems associated with overheating before the gauge does, and if you lose oil pressure the damage is done. But as you have pretty much standard everything you will be fine.

 

What tyres are you running? Unless you are running proper semi slicks you won't generate the grip needed to worry about oil surge, if you are just run another 250-500ml of oil over the full mark on the dipstick as insurance.

 

Diff ratio?? I used to run a 4.9 or 4.8, but you will be fine with whatever you have in the car.

 

Critical spares to take? I always took extra oil, some coolant, spare radiator hoses and if you still have it fitted heater hoses if they are old, a couple of spare rockers and some lash pads as my motor used to spit number 5 exhaust rocker off if i overrevved on a downchange. Also take a spare set of brake pads, and look to upgrade to a high performance road pad or a road/track pad, plus good quality brake fluid. Change brake pads and fluid before the track day if the pads are not new. Bed in properly. I would also recommend using Penrite Sin brake fluid, good price and the fluid works well, I used it in my race 240 with proper race pads no problems at all.

 

Maybe also take a set of plugs, and also a set of basic tools, socket set, spanners plus jack and stands.

 

Don't overthink it and have fun.

[mikmarda]

Awesome! Thanks for your response

 

I'm starting with test and tune days, we may enter in the 24 hours of lemons (depending on whether we meet the criteria/get the team together). Aim would be group S in the future - I just need to get it on the track before I make grand plans. Did you do anything to prevent Oil pressure loss? - such as bypass the non return (I had heard that second hand) - to prevent it jamming up? Dry sump?

 

If memory serves, the reason I ask about Diff ratios is that I bought your old locked diff! I still have the 260z rear brake setup sitting in the shed as the drums have been OK so far.

 

The tyres are old Yoko semi slicks, but I was actually thinking of getting road tyres (Bridgestone RE003s) until I/we got better (any thoughts on this). I'll just fill the oil up a little higher 

 

I've bypassed the heater coil for the reasons you've stated above.

 

Good info on the Penrite brake fluid, is this the stuff? http://penriteoil.com.au/products/racing-brake-fluid

 

- On that note I was going to drop the diff and gearbox oil and replace with a Pentrite PRO gear oil (Synth) 80-140W. Any thoughts on this?

 

Cheers,

 

Mike M

 

[PZG302]

So for track days just the basics I outlined above is needed.

 

I wouldn't worry about changing diffs until you are playing seriously, I had a range of locked diffs because I was chasing times at each track and wanted the best performance I could get, plus R180 open diffs in a range of ratios were cheap and plentiful in the '90's.

 

Just run a little extra oil in the motor. My race motor had nothing special in it and I never had oil surge or pressure problems. I was running slicks and generating a fair amount more mechanical grip than your car will.

 

That would be the brake fluid, and for the other fluids just a good quality fluid will be fine. I never replaced diff oil in my diffs after the initial fill when they were welded up. I never had an issue except when  a customer kicked a diff over so the oil ran out the breather, he cleaned the mess up and didn't tell anyone and the next day we put it in the car and it survived 10 laps at Amaroo before screaming enough with a fairly big bang.

 

If you have the tyres already just use them and have fun.

 

Pretty much prepped for track days with some better brake pads and a 2+2, well any Zed should cope with the 24 hours of lemans pretty easy.

[mikmarda]

Gooood stuff

 

Ahh that's annoying RE breather! Well I'll at least check the level then!

 

Cheers

[Brabham]

Let me know if you need any spare drivers for the Lemons ☺

[Cozza]

Hi Mike

I run a 4.6 diff at Wakefield which is good cause it keeps me out of crunchy 2nd gear but also at top of 5th on the front straight.

Have fun and I look forward to seeing you about.

Mick

[mikmarda]

Legends thanks guys,

 

I'll post on this thread after the test and tune on the 24th on progress! I'll let you know about Lemons also.

[Gordon Dobie]

You don't need to worry about diff and gearbox coolers. I would suggest the high volume oil pump as used on later 280 engines and baffled sump. The sump isn't absolutely essential but as it is such an inexpensive mod I would do it anyway. An engine oil cooler would be worth considering but not essentiall on a standard engine, I had one on my race car but it was very far from standard producing 295 bhp at 7.200rpm from 2.7 litres. I never suffered from any heat related problems in the transition department. Good luck with the project, it should be bullet proof.

[260DET]

So how did it go on 24 August?

 

You did mention doing a Lemons type event which is just a bit different to doing sprints. Significantly more engine oil capacity would be my #1 priority there.

[mikmarda]

Hi guys,

 

A quick wrap up - The car is awesome. I've attached a few pics from the day (How do you do this now) We did a 1:18 in practice which seemed pretty fast at the time until I read the times you guys are doing!

 

On the August track day we had a master cylinder failure (no biggie); then in Sep we had fuel starvation (bigger issue). got the tank dipped (Riverstone radiators - bloody legends) and found the remainder of a fuel filling nozzle in the tank that was deteriorating! On top of the sludge we though we had found our issue.

We started on the grid for lemons (that's another story), and off we went. Raced for about 2 hours...and started to lose power - (as detailed on a previous thread) the deets:

- Most prominent turning right under load - fuel tank full!!!
- Happens after an hr of racing - totally fine prior 
- Engine falters but once backed off comes good again

What we did to diagnose

Carbs tuned (SUs)
Tank dipped and cleaned - pickup and return clean
New filters
Return and delivery checked (elec fuel pump at correct pressure for carbs)
Engine fuel lines wrapped in foil
Carb bowls not hot (heat shield between headers and bowls)
Vapor lines all clear (run to atmosphere just to confirm!)

 - After some advice and closely studying other setups out there we think we'll put in a swirl pot at the pickup and bin the stock pin hole orifice and replace with a pressure regulator.

 

Any other advice?

Mike M

[dat2kman]

Have had same fuel starve issue at Qld Raceway, turn 1, then turn 2, car wouod cough/splutter.

Both are fast RH corners.

Fit a filter, then initial pump, to fill a 2 litre surge pot, , with a top overflow return back to tank, then fit a second pump, at bottom of surge pot, to push fuel to engine.