Unsprung Weight

[coln72]

Remember a couple of guys back when I was playing with the TCCV. One cut up a KE10 so it was basically a shell with a motor. No panels forward of the firewall, no doors and no panels behind the c pillar. The thing was too light. It just couldnt get traction and ended up being ballasted up.

 

Another was a KE20 (I think) that was meant to be lightened down to 600kg or so by removing as much as possible and what couldnt be removed was replaced with lighter materials. He spent a weekend making aluminium bumper brackets to save sweet &^%$% all but as has been said it all adds up.

 

If you can afford it, lighten everything that rotates, as this will allow the car to accelerate faster - think lightened flywheel.

 

Have a read of some of the Carol Smith books for some ideas on how effective weight reduction can be.

[20v4agteEL31]

enjoyed reading all of this. I bought my EP82 with 17x7.5 wheels on it, changed them for 14x7. The car somehow felt more lively with only a small weight difference between wheels. Perhaps the weight being more central in a smaller wheel has an effect also?

[irokin]

enjoyed reading all of this. I bought my EP82 with 17x7.5 wheels on it, changed them for 14x7. The car somehow felt more lively with only a small weight difference between wheels. Perhaps the weight being more central in a smaller wheel has an effect also?

 

Did the offset (and thus scrub radius), rolling diameter or tyre type change? Gotta consider all the variables together, its probably a function of all of these and more.

[altezzaclub]

Perhaps the weight being more central in a smaller wheel has an effect also?

 

Certainly it does, think of the flywheel effect- If you want to accelerate the spin of something it gets easier the closer the center of mass is to the axle. That's why you spin faster on a piano stool if you hug your arms in the way ballerinas do.

[coln72]

A bit off topic, but have you condidered running a lighter weight oil in the engine, gearbox and diff to reduce the drag on these components.

 

I have read reports of a dealer using a higher viscosity oil at the first service than was recommended and the customers were complaining about the vehicles performance being worse.

 

You should be able to get away with "thinner" oil in the gearbox. My old man ran a 50/50 mix of gearbox oil and ATF in his Aussie four speed with no reliability issues for years.

[irokin]

Unfortunately I'm pushing the reliability limits of the gearbox as it is. Even once I grow the balls to spend some money on an aftermarket gearset I'll still be running well on the safe side. $4000-9000 a gearset is not a cost I want to wear frequently.

 

Similarly the lifters pretty much dictate I use 15w40, at least that's what I've found to work best.

 

With the turbo I can live with some power losses. Its nice just being able to aim for a power figure and generally be able to achieve it. Moar booost!

[Mitch-12]

i run 5/30 in my 4k and saf/xa in my diff and i forget what i run in the box its castrol really expansive and superthin and 15/40 isnt overly thick so that is prob fine

[irokin]

Syntrax?

 

 

Got a feeling I should just make a rides thread for the dirty nissan...

[BUZ440]

Got a feeling I should just make a rides thread for the dirty nissan...

 

This, I would like to know your setup Ben,

 

curious as I am very hesitant on throwing mine around lakeside, even tho it sits out there a bit of late

[Mitch-12]

it might be syntrax or syntrans its says on the bottle its for transaxles but it works good in k40's haha

[irokin]

This, I would like to know your setup Ben,

 

curious as I am very hesitant on throwing mine around lakeside, even tho it sits out there a bit of late

 

Alright later this week I'll write something.

 

 

Definitely get into it but without knowing your skill level (and I hope I'm not being condescending) I would say go to queensland raceway first. I know the paperclip looks like a mind numbingly boring circuit but with lakeside, if you f@$kup you'll probably bin the car. I've seen the kink on the straight eat at least 3 cars in one afternoon. With QR there's lovely big gravel traps and is generally more forgiving. Lakeside is an amazing circuit but, it's got everything you could want. I still can't believe I held it flat through the kink with the speedo off the clock (180kmph+) on street tyres, pre surface repairs too :|. Easy way to catch up with lard arse GTRs :P

 

I go to Paul Ruzic's time attack days (http://www.timeattack.com.au/), next QR one is September 7. Let me know if you're gonna go and I'll come out for a look. You end up with more track time with fewer cars to ruin your hotlaps and the atmospheres generally more friendly than the circuit organised sprints in my opinion. Downside(?) is the QR days are in the middle of the week so you've gotta take the day off.

[BUZ440]

Cheers for that Ben,

 

Have given it some thought and the car has been setup for circuit work, should put it to use as Dave in his EVO keeps encouraging me to go these timeattacks, under 60secs would be nice

 

I mean owning an EVO 8 previously thinkin I'm awesome, but the Rolla in its RWD format, and having the cage makes it very stiff but sometimes can feel the rear letting go, is a bit hairy at times

 

I do agree with lakeside and its horrors, my first visit out there in 98, saw an RX3 written off on the last turn into the wall

 

During the week is also somewhat a detterence,