odurandina

late to the party,

but i love it.

77tony

Drive Dinsdale's 82 S.C. 6spd today and it's AWESOME !! T

skunkwrkz

Can't wait to get my "grubby mits" on this swap.......

slate blue

Now I will say I can't agree with this statement, the balance of the car weight will be more important than the outright weight. Removing weight from the car in the wrong places may well make the car slower. I presume you are arguing against this?

According to Kazutoshi Mizuno chief designer of the current Nissan GTR. The good handling of the GTR is down to it good weight design.

And I quote,

"Anybody that tells me a good car is one that is light with low power to weight ratio is an amateur"

Remember this is a car that looks a bit like a brick, has a relatively high centre of gravity and heavy weight around 3750 lbs but has held the production car record around the Nurburgring in Germany. A car that has certainly caused Porsche engineers a few lost nights of sleep.

The Nissans engine weighs the same as a 928 engine btw despite being compact and only six cylinders. The engine is not all that powerful being under 500 HP but achieves a 0-100 kph time of 2.8 seconds.

Again the designer says that is down to even weight distribution on it wheels. So by cutting lots of weight out of the rear the 928 is likely to be counter productive, so now you have the chief designer of the Corvette and chief designer of the Nissan GTR both saying it is not absolute weight but where that weight is placed.

Better weight distribution will be gained by the heavier transmission and differential, bigger brakes and bigger wheels etc.

Speedtoys

The GTR engineer claims magic in his statement, by the omission of AWD to pay for his sins.

GTR -vs- Porsche...apples and oranges.

Remove the front drive in the GTR, or develop an AWD 911 Cup car...then you can compare.

He is right on "where"..but..nobody at Porsche loses sleep over the GTR.

slate blue

How do you explain the difference in the speed of the 911 turbo and the GTR?

Speedtoys

Raw HP to overcome the weight of a 3900 pig. (with driver)

Once moving the tq isnt as critical, HP takes over for speed.


But like I said, apples oranges.


They dont compete in the same class of car..one is brute force with the consumables issue of a brick, the other a twitchy nimble car with its on unique plusses and minuses.

One is good for a more open track, one mo' bettah for a tighter track with no legs.


No doubt Porsche could make the 911 faster, does it need to?

slate blue

To be fair both cars have roughly the same power, or at least within 10 to 20 HP and back in 2009 the Nissan had 480 HP and was at least the match of the Porsche Turbo S at the Nurburgring which is a power circuit. Please check the relevant times. The GTR was only a fraction of a second back then slower than the Carrera GT which had another 100 HP and was over 200 kgs lighter. I don't see how 4wd grip makes much difference on such a high speed track in the dry. Remember the average lap speed will be well over 100 mph.

So when compared to the Porsche Turbo S a car with the same or more power, a car with a lower centre of gravity, a much lower weight and both have 4wd and placed on a circuit known to be a power or fast circuit.

Now if you want to ignore those facts, you still need to contend with a more relevant example to the 928 and that being the ZR1 corvette. I will try to find the interview with its chief designer and give you his direct quote but from memory he said taking away weight from the rear of the car is counter productive.

slate blue

Ok found the interview, Tadge Juechter chief designer says and I quote.

"it's kind of counter intuitive but the reason the rear spoiler is not carbon fibre is because if you make that lighter you are taking weight off the drive wheels and you are actually adding weight to the front wheels and that is not what you want. You want a share of the work load front and rear and that why we got concentrated carbon fibre up front, up high but from the doors back none."

End quote.

Much the same philosophy as the designer of the Nissan GTR which is the point I made a few days back.

mark kibort

balance is only good when designed for a speciific track or set of turns.. sometimes its better to be rear engine, sometimes its better to be front. Sometimes its better to be balanced.

Ligher is always better, except for extreme circumstances. you cant look at the GTR vs anything else , becuause it is extremely powerful and has 4x4. its running with the speed WCGT guys and hasnt done very much at only a little bit heavier. There is some cases where the car will handle better with better distribution of weight, but it has to be pretty drastic for this to happen.
THIS is why most ALL racing sanctioning bodys regulate weight and HP and not distribution of weight! its important, but its not important enough to regulate.

Its all HP. HP at the start and HP down the straight.
acceleration= power/ (mass x velocity) the 4x4 allows for more effective use of the power available. close ratio gear boxes allow for this as well.

slate blue

The Nissan GTR isn't extremely powerful, even if we talk about the current mode,l it doesn't have the power or light weight (around half a tonne lighter) like a Pagani Zonda F which it beat around the Nurburgring, it isn't made of of carbon fibre like the Zonda F. You can't compare the prices either. I think if lightweight was truly that advantageous you would see the Zonda F Clubsport winning that contest.

They do fix weight distribution in F1, a category that can afford to change weight distribution. Many catergories of racing will though say you need to use certain standard components and mounting points and this will keep weight distributions relatively stock without having to regulate it.

The weight distribution they agreed on for F1 was 45/55% a distribution that Ferrari say is the optimum for their road cars. In F1 when you could move the distribution around they Never were more than 2% outside that window and that would be unusual. So I completely dispute that a front weight bias will give advantages on a certain track or any track for that matter. Wheel bases change in F1 but that has more to do with the aerodynamics.

Another fast but not overly powerful car is the Lexus LFA and again weight distribution was a key point of development and that car is like the 928 with a front engine and rear transaxle. Weight over the rear axle is very important to get the power down, taking weight away will limit the amount of power you can apply. This difference will be much bigger than the effect of weight to power ratio.

xschop

If I could easily mount the Vette 6 speed in the 944 I would not be building the 928GTR. The limitation IMO, is the factory trans strength, gear ratios, and rear car weight for hard launches. Another 100lbs extra moved from front to rear and a taller 1st and 6th is nowhere to be found.....yet.

Renn_Thrills

>>>>Better weight distribution will be gained by the heavier transmission and differential, bigger brakes and bigger wheels etc.
most would agree with that

">>>>Removing weight from the car in the wrong places may well make the car slower."
Right, so i guess M Anderson got much slower after gutting all the weight out of the back of his?

">>>>Anybody that tells me a good car is one that is light with low power to weight ratio is an amateur"
Proof right there that you can find someone in this world to claim just about anything under the sun...

dprantl

I think what the GTR designer was saying is that it is just not that simple as a single statement. Anyone who thinks it is that simple is an amateur, and everyone should agree with that.

Dan
'91 928GT S/C 475hp/460lb.ft

xschop

At the end of the day it's all about how you want the car to perform. I'll be designing another Wilwood 6-pot BBK for the front so I can have a multitude of pads to choose from, front and back, to tune braking nuances. Remove all carpet padding, back seat BS and throw on 40 lbs of supercharger goodies to the front and it is what it is.