How much faster 0-60 would you say a Z is with a chip and running 15psi?

 

Has any one got any times, as when I went for a drive, it felt very fast but its hard to say how much faster I was going. I felt when the car reached 80mph as it is now, would have been the same time I reached 60mph when stock.

 

Any thoughts?

 

I tried to video my first drive with my car like this, but I has no where to attach it to. I put it on so it was looking at my turbo gauge so you can see how much faster it moves :D but the gear stick got in the way some times and it kept getting moved too :S

 

Stuart

timed mine using a 0-60 timer

 

mods: JWT induction, Mongoose zorst, JWT chip, 16psi (ish) on boost jets, Fidanza Flywheel & RPS clutch.

 

4.8 secs which i was most pleased with.

 

 

for reference when it was stock on a slightly slipping clutch i done 5.9 secs

 

after putting the clutch, flywheel, induction & zorst I got 5.3 secs

 

I really need Hybrids & to decat now :D :dance:

Am I right in saying that you will notice the power increase more at the top end rather than 0-60 ?

Personally I think that 30 onwards is a lot faster. 1st gear it is almost too powerful with most of the time the wheels spinning.

 

Stuart

I think mid-range is where I noticed it most. :D

Right across the range defo, 1st gear is so quick I cant really tell the difference between stock boost and 12psi lol

 

Mind you its spins the back tyres easier :cool:

Remember its an increase in torque not power which increases the rate of acceleration.

Top speed is determined by drag coefficient power, weight and gear ratio.

 

Thats why Turbo Diesels are so usefull at overtaking so much torque. By the way whats the stock torque on a 300zx tt and what rpm is the peak?

I think its 286 f/lb @3600rpm.

 

Which is quite a lot and at a good position in the rev range.

 

 

Stuart

Originally posted by Welsh Beef

Remember its an increase in torque not power which increases the rate of acceleration.

Top speed is determined by drag coefficient power, weight and gear ratio.

 

Thats why Turbo Diesels are so usefull at overtaking so much torque.

 

For overtaking it's not so much the torque peak itself, it's the fact it's there straightaway. However this also happens in variable timing turbo engines like the Z...

 

My Leon TDI has peak torque at 1850rpm and it lasts until 4150 which is about half the rev range (redline at 4800).

 

Z has peak torque at 3600 which lasts until high 6k, so again, it's about half the rev range. So in fact, you drive them both the same way to get the best out of them. (Er, sort of, although gear changes are very different in the two cars.)

 

The difference is the ratios have to be longer in the Leon to get to the top speed - 4k rpm is pretty much smack on 110mph in 5th. In the Z 110mph is only just past the top of 3rd!

 

Therefore, the Z is way quicker because torque AT THE WHEELS depends on gearing as well as flywheel torque. The engine is revving twice as quickly at 110mph in the Z compared to the Leon, and the gearbox turns those extra revs into performance, so to speak.

 

Power is proportional to the product of torque and engine speed, so a high power figure tells you the engine delivers torque at high revs. This means you can gear it lower and hence you'll have good torque at the wheels. That's really why people bandy BHP figures around - a high BHP figure means it's quick AND you can use long ratios.

 

Power is a function of torque, not the other way around...

 

Not very coherent, sorry, one day I'll write a proper article on this and stick it on the Web, but I'm willing to take questions meanwhile!

Originally posted by zevans

 

Not very coherent, sorry, one day I'll write a proper article on this and stick it on the Web, but I'm willing to take questions meanwhile!

 

I have a question.

 

When is your car gonna be ready ;)

Mine was 350lb/ft @ 3250rpm - but it is an auto (or was) ! ;)

 

 

Originally posted by SRRAE

I think its 286 f/lb @3600rpm.

 

Which is quite a lot and at a good position in the rev range.

 

 

Stuart

In my Dads Golf GT TDI PD you get 35mph per 1000rpm in 6th so the theroetical top speed at rev limiter would be 168mph. However this is not the case you can only really get about 135ish. The reason is that at this speed the rpm is 3850rpm this is not peak power hence if the gear ratio was shorter at this speed the rpm would be higher but also there would be more power so you would b able to achieve a higher top speed.

 

Drag from frontal surface area and weight in this example are constant.

 

 

On a different note by increasing the size of the wheels say 15 to 18's many would believe that the top speed is increased - this is not the case (in cars not able to reach their rev limiter in top gear) as at the same speed the rpm would be lower and so would the power therefore the car would not be able to accelerate further unless you increased the power.

 

A fine example of this is the Lotus Carlton with 50mph per 1000rpm rev limiter nearly 7000rpm so based on simple maths you could achieve 7*50 =350mph. However its top speed std its about 175mph which is only 3500rpm and not matter how long a stretch you find you will not get much more than this. Also Holden GTs.

 

Ideally car makers should make cars hit top speed in 5th at peak power and 6th is a economy gear where even if you changed down at the max speed in 5th the car will slow to a lower top speed in 6th. Sports cars however will have all 6 or 7 forward gears designed to achieve top speed at peak power output in top gear/highest gear in the car.

Originally posted by SRRAE

I have a question.

 

When is your car gonna be ready ;)

 

'kin good question - trust me to pick a week Phil's on holiday to have mega problems! Been off the road more than on recently.

 

Mithered them twice this week already... might nip over and mither in person tomorrow.

 

And I've got a NIP from the bloody Snake Pass... I swear I drove at 59mph all the way between those ******* av speed cameras. Strangely the NIP doesn't state a speed - can that be right?

 

[sigh] :cry:

Originally posted by Welsh Beef

The reason is that at this speed the rpm is 3850rpm this is not peak power hence if the gear ratio was shorter at this speed the rpm would be higher but also there would be more power so you would b able to achieve a higher top speed.

 

[...]

 

Ideally car makers should make cars hit top speed in 5th at peak power and 6th is a economy gear where even if you changed down at the max speed in 5th the car will slow to a lower top speed in 6th.

 

 

When I read your first paragraph I thought to myself I'd reply and say just what you've said in the second paragraph - the six-speed box is geared for economy. I dimly remember when I was a kid and Dad bought his first five-speed car it would go faster in fourth than fifth.

 

The Golf is

a) a town car (the Passat is the motorway car)

b) sold all over Europe where speed limits are all ~100kph+

c) marketed on economy

 

- so no point having a top speed over 120 anyway, really.

 

I've never done the maths for other cars - interesting - thanks!

 

Finally as well as the 'box and the wheel size, don't forget final drive ratio is in there somewhere too!