Can someone do a little performance test for me (+ random saxo questions)

29th April 2009, 02:46

I've been working away at a little excel sheet that calculates all sorts of stuff like 0-60 times 0-100 time and everything inbetween along with 1/4 miles drag times and stuff. lot of equations... not a lot of sex, as you'll probably be able to tell when I 'release' it if there's the interest.

unfortunately, to get all this information I've had to introduce a few guestimates/constants on engine properties but I think I'm in the right area now, top speed is 99.9% correct which I'm chuffed about... but to confirm acceleration I could do with a few homies doing a couple of measurements for me...

Could someone (or ideally a few people) with a standardish (doesn't matter too much) VTS time how long it takes to go from 5000rpm to 7250rpm (or just before the limiter) in second gear? should take (according to my calcs) 3.2 seconds. If it isn't then I need to do a bit of jiggerypokery.

Then do 5000rpm to 6500rpm in 3rd which should take about 4.5 seconds.

Random saxo questions:
roughly what is the weight of an 15" alloy with tyres... just so I've got a figure.

CHEERS!!!!!

29th April 2009, 08:17

As I've got a different gearbox, I guess you wouldn't want me to do this?

Why are you asking the weight of a 15" alloy wheel? You were the one who was meant to find out the weight of the standard VTS wheel! Anyway... Most common 15" alloy wheels weigh anywhere from 6.5kg to 8.5kg. 195/45/15 tyres (not semi-slicks) weigh around 8kg.

29th April 2009, 08:20

Any chance of a copy of this spreadsheet?

29th April 2009, 08:34

Quote:

Originally Posted by Toad

As I've got a different gearbox, I guess you wouldn't want me to do this?

Why are you asking the weight of a 15" alloy wheel? You were the one who was meant to find out the weight of the standard VTS wheel! Anyway... Most common 15" alloy wheels weigh anywhere from 6.5kg to 8.5kg. 195/45/15 tyres (not semi-slicks) weigh around 8kg.

I can change the ratio's it's not a problem really, although your's is cammed which a bit too far tuned from standard to really validate the excel sheet, (going on manufacturers technically specs).

Yep I know the weight of the alloy itself but it's the tyre that's the heavier part of the two... so just any old measurement will do

so 8-12kg is a good ball park figure to start with then?

Quote:

Originally Posted by SaXo_vtr123

Any chance of a copy of this spreadsheet?

That's the plan!

29th April 2009, 08:35

Quote:

Originally Posted by adsayer

That's the plan!

Woop, maybe ask for a sticky where you can put the link?

Is it better than that one of "torque cars" or whatever its called?

29th April 2009, 08:42

Quote:

Originally Posted by SaXo_vtr123

Woop, maybe ask for a sticky where you can put the link?

Is it better than that one of "torque cars" or whatever its called?

mate, trust me it'll shit on everything... already does, smug mode for me on this but I'm bloody happy with it... I'm just fine tuning. It takes into account, wheel, engine cutch inertias, equivlant mass of the vehicle, dynamc rolling radius (which modifys the torque output to the road and also the top speed), aerodynamic drag, rolling resistance etc etc But I'd rather hold on to it and 'release' it once it's absolutely PERFECT rather release some half assed shite that of no use to anyone (like, say, Microsoft), then continually update it.

The down side is you really need a Rolling Road of your engine to make it work properly... but then again I could introduce a rough calculation for people that havent???

29th April 2009, 08:42

Quote:

Originally Posted by adsayer

I can change the ratio's it's not a problem really, although your's is cammed which a bit too far tuned from standard to really validate the excel sheet, (going on manufacturers technically specs).

Yep I know the weight of the alloy itself but it's the tyre that's the heavier part of the two... so just any old measurement will do

so 8-12kg is a good ball park figure to start with then?

That's the plan!

8-12kg? Where did you get that figure from?

29th April 2009, 08:45

VTS wheel inc tyre is 16kg+

29th April 2009, 08:46

because we're talking VTS rims here....

29th April 2009, 08:49

Quote:

Originally Posted by adsayer

because we're talking VTS rims here....

You're talking jive turkey. I've still no idea what you're on about! lol.

29th April 2009, 08:49

Quote:

Originally Posted by AlexR

VTS wheel inc tyre is 16kg+

knew it.

29th April 2009, 08:53

Quote:

Originally Posted by adsayer

knew it.

well knew it in the sense that I knew it'd be quite high anyway haha

Quote:

Originally Posted by Toad

You're talking jive turkey. I've still no idea what you're on about! lol.

Ok, remember the gubbins about wheel inertia yeah? I need wheel weights to knock out a rough/but very useable figure for the wheel inertias you see...

29th April 2009, 10:02

Stop digging a hole. I'm talking about the 8-12kg figure you mentioned.

29th April 2009, 10:14

I've gota go out in abit Sayer so I'll do it then ... Mine isn't that much quicker than standard according to that RR so i'm sure it's better than nothing.

5000rpm to 7250rpm in second gear - 3.2 seconds?

5000rpm to 6500rpm in 3rd - 4.5 seconds?

29th April 2009, 10:16

I have a few videos of my car on my Photobucket you might be able to take times from.

A 0-60 run I filmed, so could work out the 2nd gear time, but I did short shift it..

Also, I have a VTS wheel I might be able to weigh for you, and I will get the measurements later

29th April 2009, 11:09

Quote:

Originally Posted by Ferg

I've gota go out in abit Sayer so I'll do it then ... Mine isn't that much quicker than standard according to that RR so i'm sure it's better than nothing.

5000rpm to 7250rpm in second gear - 3.2 seconds?

5000rpm to 6500rpm in 3rd - 4.5 seconds?

that'd be awessssommmeeee man cheers

Quote:

Originally Posted by Jorge-

I have a few videos of my car on my Photobucket you might be able to take times from.

A 0-60 run I filmed, so could work out the 2nd gear time, but I did short shift it..

Also, I have a VTS wheel I might be able to weigh for you, and I will get the measurements later

No probs about short shifting, I've rpm increments of 50rpm so I can just use whatever data I need and see if it correlates...

Everything I've been tweaking it again earlier today and it looks good, just got to make some sort of clutch slipping calculation when the goes from zero to moving

at the moment its done from 1000rpm which is unrealistic (but nice and easy to get me going).

a few pics....

29th April 2009, 11:12

I hope this comes with an instruction manual Ads.

29th April 2009, 11:12

PM'd Videos

First 2 are with Magnex, Raceland Induction, 4-2-1. And partially stripped.

Ones before are with the Ashley exhaust

The earliest ones (date in file name) is with the Raceland fitted, and there might be one with standard airbox and exhaust

29th April 2009, 11:14

yeah it's not very intuitive at the moment, mind you, I never intended to develop it in the way it's gone

If I'd thought about it from the beginning I would have done it differently but NOOOO way am I changing it now... I'll try and make it a bit more user friendly and understandable though!

29th April 2009, 11:17

Alright PC is playing up, will get em later

29th April 2009, 11:18

I have a VTS running an R box. Im quite willing to have ago if its anygood to you?

29th April 2009, 11:22

5000rpm to 7250rpm in second gear - 3.2 seconds?

5000rpm to 6500rpm in 3rd - 4.5 seconds?

4.5 seconds to go up 1.5k rpm? at 5k.. it'll be pulling alot? seems high.

29th April 2009, 12:48

Judgeing by them screenshots, its looks amazing!!

When can i get a copy?

What does the change in circumference on the line graph mean?

29th April 2009, 13:07

Quote:

Originally Posted by SaXo_vtr123

Judgeing by them screenshots, its looks amazing!!

When can i get a copy?

What does the change in circumference on the line graph mean?

not a for a while man, unless you're happy sorting out power inputs and adjusting the equations to match you engine speeds??

As the wheel on a car spins faster, the centrifugal force increases which causes the tyre diameter to expand slightly... which affect the speed, acceleration and rolling resistance of the vehicle.

The data was taken from standard SAE (Society of Automotive Engineers) tables then I put a interpolation macro in so it could give the circumference increase at any speed (up to 150mph)

ads

29th April 2009, 13:07

Quote:

Originally Posted by saxova

5000rpm to 7250rpm in second gear - 3.2 seconds?

5000rpm to 6500rpm in 3rd - 4.5 seconds?

4.5 seconds to go up 1.5k rpm? at 5k.. it'll be pulling alot? seems high.

what the time? this is why I need to check!

ads

29th April 2009, 13:08

Quote:

Originally Posted by liam08

I have a VTS running an R box. Im quite willing to have ago if its anygood to you?

if it's a standard VTS and a standard VTR box then yes please mate!

29th April 2009, 13:09

Quote:

Originally Posted by adsayer

not a for a while man, unless you're happy sorting out power inputs and adjusting the equations to match you engine speeds??

As the wheel on a car spins faster, the centrifugal force increases which causes the tyre diameter to expand slightly... which affect the speed, acceleration and rolling resistance of the vehicle.

The data was taken from standard SAE (Society of Automotive Engineers) tables then I put a interpolation macro in so it could give the circumference increase at any speed (up to 150mph)

ads

I think i will leave it to you and your amazing brain, until you can make it for more normal people

You really are a theory god lol

29th April 2009, 13:31

Rights ads my man ... Took video's and then used an online stop watch so should be fairly accurate.

5000rpm to 7250rpm in second gear - 2.8 Seconds

5000rpm to 6500rpm in 3rd - 3.2 Seconds

Can send you the vid's if you like also ...

29th April 2009, 16:05

Post all the vids in the thread. Would be good to see

29th April 2009, 16:08

I will post my 0-60 video, I am happy with it.

I did one on the empty tank, but spun the wheels, so I thought maybe if I turn on the fog lights I will go faster, and amzingly I did.

FUCK

On this screen that might as well be black. I NEED new dials lights I think

29th April 2009, 16:37

Quote:

Originally Posted by Toad

Post all the vids in the thread. Would be good to see

Ignore EML ... It's from De-Cat.

2nd gear ~

3rd Gear ~

29th April 2009, 21:00

2nd gear in my car is 2.7 mate. Decat, supersprint and Predator...

Will do 3rd tonight for ya!

Andy

29th April 2009, 22:24

I don't know if this will help but you should be able to work out engine speeds working backwards but I did in 3rd 80-120km/h (Roughly 50-75mph) in 5.3s GPS recorded.

29th April 2009, 23:13

woahhhh guys! Thanks! awesome response... right I've looked at vids and the times and it's clear my (further tweaked) simulation is slightly down (by give or take 0.2secs)... which I think is largely going to be down to individual engine characteristics now (i put my original standard VTS power run in for validation).
1/4 mile times look about right, 1 km times look about right, 0-60 time is about right, top speed is now bang on,
So I'm mega happy with it.

just want to replace the linear interpolation with a cubic spline interpolation and make it a bit more user friendly and it's done. At the moment it's really just suitable for standard limiter (modified intake and exhaust is fine though) VTSs

This is because it's an absolute pig to alter the rpm shifting point....
it'll make more sense once you see it.

Ads!

Ps. this is all excel based so it's never going to be massively user friendly sadly

29th April 2009, 23:17

Okay,

I got you some measurements

this K&N

90x265x17

29th April 2009, 23:19

Quote:

Originally Posted by Jorge-

Okay,

I got you some measurements

this K&N

90x265x17

wicked!
mm's yar? how many pleats dude?

29th April 2009, 23:21

14 at aprox 6mm thick