Cheap Performance Meter

[Rusty]

Cheers for that Paul.

Rollout is for using on the drag strip. You want to take it off for road testing really as it takes into account the timing gear lag... I haven't seen any timing gear on my local A or B roads...

[S2central.net]

Yeah - its just one of those parameters set at GTech defaults... I haven't bothered to tweak it... Same as pitch correction...
Figured if I keep those params the same then the data is more consistent for my car at least - but I agree it makes it harder for likes of you and me to compare results... You shoulda bought a GTech RR - I'm kidding... I fully appreciate why you took the GPS approach.

[Rusty]

Yeah, the small matter of £200 off

[Rusty]

Been having another play with this. There's some free software on the performance box website that's brilliant. You can edit the data logging runs down and then measure speed and distance performance tests. It's grrrrrrrrrrrrrrrrrrrrrrrrrrrreat

Not sure how I managed it but I logged a 0-100kph in 5.2s today, 0-60 in 4.9! More like 5.2 repeatable TBH. I'll compare them on excel tomorrow and see. Also got a metric for 30-60 of 3.05s, that compares to 2.75 for a tweaked B5 S4 2 up

[Rusty]

[Jonas_R]

Been playing around with my GPS and maxqdata. When you do horse power measurements Andy, any gear that seems to be the most realistic? I tried in 2nd and 3rd gear but that seem to gave measurements why of whereas 4th gear seem to be the best.

[Rusty]

TBH the BHP calcualtions were quite difficult, the only way to do it was to get the figures to a known point such that when you changed something it would show the difference, with that in mind there's no need to calculate the figures, just doing a second gear run and comparing from a full boost start point like 35mph was sufficient. I've been using 2nd gear 30-60 times to quantify gains recently as this is a good metric of a stock ABY.

[Jonas_R]

Ok the program I use make the calculations for me so, but the result seems to be off in 2nd and 3rd gear. Even though the GPS is 10hz it seems to go to fast in 2nd and 3rd.

[Rusty]

How far out is it? Torque will be late and low due to lag effects, real power should work. Wheels to fly conversion is approx 1.3 at 6kRPM, Cd.A is approx 0.6 . The flywheel inertia has a much larger effect in 2nd/3rd, a few bhp anyway.

[Jonas_R]

It was very far out switching between 230 HP to 630 HP, but found out that I had forgotten to plug in the unlock code after i upgrade to the newest version.
That made the damn thing record in 1 Hz and not 10 Hz. Properly why it was way off in lower gear and better in higher gear.
Will give it a go tomorrow and see how it turns out. But the MaxqData is actually rather nice and quite a few options once you bother to read the 150 page manual

[Rusty]

This has turned out to be a good little toy. I have used it to do a lot of testing over the last 6 months, easily got my £50 back out of it. Currently using an old N73 in offline mode with a 2GB card in, logs more data than I'll ever use The repeatability of in-gear tests is very good, these are 5 runs for the S2 today (about 18degC and with -80kg).

2.89s
3.00s
2.96s
2.96s
3.02s

Standing start data isn't quite so good as 0 speed on GPS doesn't really exist... the transition from stopped to starting is back calculated (as stated previously) and there can be errors. The other error over a G-Tech is when you're on a tree-lined road, something there seems to be a lot of round here.

[Rusty]

Used this today on my 150ish bhp BMW 318is, 0-60 was really impressive for it, average of 6.85s over 10 runs! I thought it had broken on the first runb so did another and it was about the same, very suprised as that's seriously fast for what it is! rev limiter in 2nd was 60.7mph so couldn't be much better setup for that particular test

[EspenW]

Not bad at all. How much does it weigh?

[Rusty]

1100kg or so, I think there was about 50kg of luggage and crap in the boot too.

I was genuinely suprised, so suprised that I did 15 runs with a full reset in the middle and used 2 programs to test the data It's rwd so you can launch it well and revs like mad so once it gets past the launch phase (4k5+) it just keeps chasing the red line (7K+). I knew it felt quite strong but seems that the atmospheric conditions of about 1040mBar and 5degC might have given it a little hand there too! Makes me want to tune it some now A flow job and decent inlet would be a nice start for sure... all dreams for now.

[EspenW]

Yup, RWD can launch much, much better than FWD. My 930kg Golf (2L 8v with around 150hp) runs to 60 in 6.5 on a Mk1 G-Tech and 6.7 something on the MR Dyno, but it is very traction limited in 1st gear, it actually has as much torque as a tuned VR6 around 3000rpms, so it breaks away easily in 1st, and will slip hard in 2nd as well when there is a little moisture on the road.