10% more power, 10% less weight, 10% better braking or 10% better grip? - Page 6 - Perth-WRX.com

trusti rex · #51 09-09-2008, 12:12 AM

Quote:

Originally Posted by subarooboy

... So don't these 2 last statements kind of bring us right back to the point I already mentioned?

You've just said it right there- weight means very little in todays cars, it's the grip that is most useful!???

(Heat that popcorn up anyway Joe- you know I'm good at pushing buttons)

hmm... yeah but were talking about giving it an extra 10% of grip
gtr is a prime example - already has the wide tyres/electronics/suspension for the grip so how do you improve the grip? wider tyres? well you could chuck a set of top fuel tyres on but really...how wide can you go? i reckon you would struggle to give the gtr 10% extra grip without reducing weight. you could write a book on the subject, but a car with lower weight will turn in the quicker lap time of the two, because less weight works with the car the whole lap, even on the straights and large radius corners, where grip isnt really an issue. so overall, weight reduction is better bang for buck imo

Q. i'll give you one guess what the v-spec gtr's engineers focus is on...
A. thats right folks a 220lb weight reduction

Kato · #52 09-09-2008, 07:19 AM

Quote:

Originally Posted by trusti rex

hmm... yeah but were talking about giving it an extra 10% of grip
gtr is a prime example - already has the wide tyres/electronics/suspension for the grip so how do you improve the grip? wider tyres? well you could chuck a set of top fuel tyres on but really...how wide can you go? i reckon you would struggle to give the gtr 10% extra grip without reducing weight. you could write a book on the subject, but a car with lower weight will turn in the quicker lap time of the two, because less weight works with the car the whole lap, even on the straights and large radius corners, where grip isnt really an issue. so overall, weight reduction is better bang for buck imo

Q. i'll give you one guess what the v-spec gtr's engineers focus is on...
A. thats right folks a 220lb weight reduction

Easy, take off the street tyres and put on some sticky race compound. There is a big difference between the grip in a set of Bob Jane $99 specials and a set of drag radials/r-comps/slicks.

Also, it is not a simple fact of removing weight. You also need to factor in the dynamics of the suspension to cater for that. Easiest example is go jump in a ute, which has stuff all weight over the back wheels making it a completely different drive to a sedan. But will do bulk skids on demand for you.

So by removing weight you would then have to change the suspension geometry and stiffness of the vehicle to compensate. This then goes further than the just losing 10% weight, and we are back to my previous comments.

subarooboy · #53 09-09-2008, 01:01 PM

Quote:

Originally Posted by Kato

Easy, take off the street tyres and put on some sticky race compound. There is a big difference between the grip in a set of Bob Jane $99 specials and a set of drag radials/r-comps/slicks.

Also, it is not a simple fact of removing weight. You also need to factor in the dynamics of the suspension to cater for that. Easiest example is go jump in a ute, which has stuff all weight over the back wheels making it a completely different drive to a sedan. But will do bulk skids on demand for you.

So by removing weight you would then have to change the suspension geometry and stiffness of the vehicle to compensate. This then goes further than the just losing 10% weight, and we are back to my previous comments.

... And sort of touching on some of my comments (which are really Ken's!) re: manouverability of a vehicle in relation to weight.

When I mentioned lighter vehicles being 'skittish' earlier, this wasn't based on suspension being to stiff etc but more along the lines of using Kato's perfect example of a ute. Being RWD there is a difference of course, but a good example for observation- high speed cornering can be a bitch due to the light rear end and rear power... whereas the same model in sedan will usually comply and be more predictable with handling.

The weight has a direct relation to the suspension setup- by shedding the pounds you can often fuck with this whereas sticking with the manufacturer settings and increasing overall grip (such as the example of adding R-comps- even RE070s!!), I believe will give the better lap times due to pre-engineered predicatbility of suspension components and adhesion making them work more effectively!!