Monoposto Racing Forum

I have bought an AIM display/logger unit, I have a few things I am not clear on. It has a gear display function, I am not sure if the car has a gear sensor. Is this something that can be fitted?

Reading the manual, I think it can also work out the gear based on rpm/ speed values...is this method accurate?

Where is the best place to pick up the oil temp?

Also can anyone explain the difference between a normal pressure sensor and a VDO version? as the wiring is totally different between the two.

I will be wiring up the unit to get the following info,

1.oil pressure,
2.oil temp
3.water temp

4.rpm
5.speed
6.gear - if possible

Sorry if these questions annoy anyone... Just trying to clarify a few things.

I think you program the system with your gear ratios and it works out what gear your in based upon speed and revs.

Oil temp - probably where its hottest which is probably in the cylinder head, but probably nearest the factory oil temp/pressure sender for ease of fitting

Thanks for that, once I have wired it in I will see how it works.

Any ideas on the pressure sensors?

samier wrote:I have bought an AIM display/logger unit, I have a few things I am not clear on. It has a gear display function, I am not sure if the car has a gear sensor. Is this something that can be fitted?

Reading the manual, I think it can also work out the gear based on rpm/ speed values...is this method accurate?

Yes, this method is quite accurate, as revs vs speed are a constant. It might only get confused if you have a LOT of wheelspin, spend much time in neutral, or heel and toe with excessively large throttle blips.

samier wrote:Where is the best place to pick up the oil temp?

Somewhere hot with oil flow (unlike oil pressure, which can be situated out of the way on a dead end drilling/pipe). Is there a threaded drilling onto the main oilway?

samier wrote:Also can anyone explain the difference between a normal pressure sensor and a VDO version? as the wiring is totally different between the two.

A normal pressure sensor is designed to be accurate. A VDO gauge isn't, and is just used to give a very vague idea of a value without much fluctuation - not what you want on a datalogging system!

samier wrote:I will be wiring up the unit to get the following info,

1.oil pressure,
2.oil temp
3.water temp
4.rpm
5.speed
6.gear - if possible

Sorry if these questions annoy anyone... Just trying to clarify a few things.

I wouldn't worry about oil temp initially, as oil is very forgiving and will work happy over a very broad range of temperatures. Water temp and oil pressure should be enough to tell you what you need to know 99% of the time.

Will you be measuring speed via a wheel sensor, or via GPS?

Thanks Tristan!

There is such a difference in price, stack sensors going for around 70 pounds, others cheaper at 20 odd.. does it make any difference in reading and accuracy?

http://www.gprdirect.com/OnlineShop/Pro ... =214&g=661

http://www.gprdirect.com/OnlineShop/Pro ... 39&p=41453

When I took my oil pressure/water temp gauge, there was a pipe that I also removed, I guess I fit the pressor sensor to that pipe right?

I will be using wheel speed sensor untill I buy the GPS module.

I have this kind of sensor as per picture.

Do I drill a hole in the plate and fit the small magnetic end, make a bracket and mount the threaded sensor?

samier wrote:Thanks Tristan!

There is such a difference in price, stack sensors going for around 70 pounds, others cheaper at 20 odd.. does it make any difference in reading and accuracy?

http://www.gprdirect.com/OnlineShop/Pro ... =214&g=661

http://www.gprdirect.com/OnlineShop/Pro ... 39&p=41453

When I took my oil pressure/water temp gauge, there was a pipe that I also removed, I guess I fit the pressor sensor to that pipe right?

I will be using wheel speed sensor untill I buy the GPS module.

I have this kind of sensor as per picture.

Do I drill a hole in the plate and fit the small magnetic end, make a bracket and mount the threaded sensor?

Stack two wire, Racetech single wire?

A vdo Sensor..



An MSI sensor..



Trsitan, so you are saying that a VDO would be no good for oil pressure? Why would AIM recommend such sensor if it were no good???

It depends how accurate you want your oil pressure readings. Do you want it to merely give an idea of whether you have some pressure or not (VDO), or would you like to know whether you have 55psi or 60psi for the purposes of engine diagnostics and to help with the quest for power?

VDO don't make datalogging parts in my opinion. But then again, neither to AIM. (but that's just a) my opinion and b) my elitist attitude :p

Well I can live with +/-5% accuracy of the VDO. No point spending another £100+ on getting +/- 1%.