Autosport Labs

Not entirely Megajolt specific, but i guess this is the best place to ask this type of question....

The story goes something like this: i want to male a cunning little box that converts things like acceleration, engine speed, road speed and lambda values into DC voltages which can then be fed into another cunning little box which turns the voltages into something my laptop will understand. the plan is that when i come to install an MJLJ in the Mini, i should be able to log performance data on the laptop and thereby quantify the effects of any changes made to the engine map (without paying £60/hr on the rollers). Conceptually, it's all there. box one exists in my head, and box 2 costs around £100 from RS.

The only thing i'm worried about at this stage is writing to the hard disk of the laptop whilst accelerating up and down the backroads of wiltshire - are the inevitable bumps going to make the disk heads crash?

I read with some interest about the data logging capability of the latest release of the MJLJ software. Does this write straight to hard drive? if so does anyone have any experience logging whilst in motion?

More to the point, can it read and log an external voltage over time? this could be rigged up to a fairly simple(???) accelerometer, giving me everything i need (for the time being anyway - Lambda is a long way off!)

Anyone's thoughts on the matter would be gratefully received.

...are the inevitable bumps going to make the disk heads crash?
<b>Probably</b>. Normally dataloggers write their multiple channels to solid state memory and you download that to a PC when you're done (or they blast it back to the PC via a radio link as you go past it if you're in F1 or WRC!)

...Does this write straight to hard drive?...
<b>Yes</b>

More to the point, can it read and log an external voltage over time?...
<b>No</b>

To be honest, if it's £100 for box 2, £x for box 1, £y for all the sensors you need, crashing the heads on your laptop disk, working out how to cope with the accelerometer not being exactly horizontal nearly all the time and a few other things, I'd go down the rolling road.

Do your prep on the general engine condition first, and it shouldn't be more than a 45 minute job if the operator knows anything about tuning with 3D mappable ignition, whether it's MJLJ or not

PS Yes I've been playing with <b>bold tags</b>!

Mmmm, you guys are paranoid about this a little too much. In the US every cop car is equipped with a laptop, mounted to a solid metal stand, which is then mounted to the frame. And those are body on frame cars, not some unibodies. Ive supported police departments, and almost never it was a bad hard drive, most often battery, or bulb in LCD. So Id say you have nothing to worry about it, especially if you going to have your laptop on soft rear or passenger seat.

Sure, if you do a big yump and your laptop is not tied down, and bounces against your dash, then rear windshield, of course it will go bad. But on a soft seat, I dont think so.

Now with that said, data is not always written to hard drive. Hard drives have cache memory, and considering low resolution of logger on Brents software (about once every 100ms), it will take a few minute for data to be written to disk. So write operation wont happen while you going over bumps, at least not every time.

Hi,
I have bought a second hand Race Technology DL90 data logger for well under £200.
This is a really good bit of kit and has extremely good software.
Has 2 accelerometers, gps postion and vehicle speed, engine rpm input, 2 external 0-5v inputs , thus log tps, lambda etc and a +5v regulated voltage to power sensors, 90min of on board logging @ 100Hz for all channels.
Only thing it can't do is log the spark position but you can input car weight, aero/tyre drag and log car accel to produce power curves within the software.
An easy option and worth a look if you already haven't been down that route.

hmmmm.......

thank you so far.

yes, martin, i myself have questioned whether it's worth doing at all. but it sounded like fun so i thought i might give it a go. on the other hand it seems much easier to buy a box that does it all anyway. then i can get on with having fun mapping the engine which is what i really want to do anyway.

i'll be having a look on ebay then. matnrach, where did you get yours?

Ebay.
You have to keep looking.
Other sites you could try are racecars direct, fastroad and track.
You could also call up Race Technology and see if they have some old units as they sometimes sell them on as they now only sell a newer model.
Hope that helps.