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

Barry123 · 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!!!!!

Toad · 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.

JamesR^m · 29th April 2009, 08:20

Any chance of a copy of this spreadsheet?

Barry123 · 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!

JamesR^m · 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?

Barry123 · 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???

Toad · 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?

AlexR · 29th April 2009, 08:45

VTS wheel inc tyre is 16kg+

Barry123 · 29th April 2009, 08:46

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

Toad · 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.

Barry123 · 29th April 2009, 08:49

Quote:

Originally Posted by AlexR

VTS wheel inc tyre is 16kg+

knew it.

Barry123 · 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...

Toad · 29th April 2009, 10:02

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

Ferg · 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?

Jorge- · 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

Barry123 · 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....

Mochachino · 29th April 2009, 11:12

I hope this comes with an instruction manual Ads.

Jorge- · 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

Barry123 · 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!

Jorge- · 29th April 2009, 11:17

Alright PC is playing up, will get em later