UPDATED: K series oil pressure - data from a racecar - ADDED VIDEO

[CharlesElliott]

Thought some of you might be interested in the oil pressures logged in a race car. The car is a 1.6, 120bhp K series with an Apollo, wet sump on Yoko A048R tyres.

 

You will need images enabled. I have now also added a video of the lap that produced the data.

 

So, here is a picture of Silverstone, the start/finish of the lap being indicated by the red marker.

 

http://tripleeracing.co.uk/oil/Silverstone.png

 

Now, this is a trace of lateral g, speed, rpm and oil pressure over one lap (pressure is in psi). You can see that it varies between about 24 and 85 psi over a single lap.

 

http://tripleeracing.co.uk/oil/Trace.png

 

This is a trace of the circuit coloured by oil pressure - blue being low and red being high. The lowest value in each sector is indicated. This is a pictorial version of exactly the same data in the trace above.

 

http://tripleeracing.co.uk/oil/SilverstoneColourCoded.png

 

This is an X-Y graph of a single lap - lateral G against pressure. You can see that left hand turns have little impact on pressure when compared with right hand turns.

 

http://tripleeracing.co.uk/oil/GvsPressure.png

 

Finally, you can see a slightly rough and ready cut of the lap that produced the above data. Whilst not all the sensors are plugged into the virtual dash, it gives you an idea of exactly what is going on and you can see oil psi in the lower right.

 

HD video of lap with virtual dash

 

I hope this provides something a little bit more scientific than people trying to drive round roundabouts whilst looking at their mechanical pressure gauge 😬

 

Edit: To fix left/right error, to add video details/link

 

Edited by - CharlesElliott on 7 Apr 2011 22:31:25

[myothercarsa2cv]

Brilliant! Very interesting and pretty too

[Roger Ford]

No video?

[Grubbster]

Never mind all that rubbish - how long did it take to get round 😬

 

Very nice data logging and well presented

[Shad]

Very very interesting, love stuff like this. Thanks for posting

[CharlesElliott]

Around 1:08.5 for that lap.....

[Mankee]

Quoting CharlesElliott: 

Finally, this is an X-Y graph of a single lap - lateral G against pressure. You can see that right hand turns have little impact on pressure when compared with left hand turns.

What an excellent and informative post! I am slightly confused by the above though. Surely, the right handers cause the oil pressure to drop off and the left handers don't make a huge amount of difference? The opposite to what you say in the quoted bit.

 

Be interesting to see what the traces look like around the new layout of Snetterton as some of the right handers are looooooong. And also Gerrards at Mallory and Park at Cadwell, maybe.

[CharlesElliott]

Yes, you are of course correct. Edited to fix that error!

 

I'm at Snett next weekend 😬

[Mick Day]

When I had a wet sump the OP would drop on LH bends.

[Dignity]

Thanks for the post Charles

Interesting reading but what I would like to know is how bad is this?

Clearly 24psi is not ideal but at least the revs were lower. Is this putting the engine in danger?

Also how much protection is the Apollo offering? Without it would the pressure be dropping away to zero?

Regards

Dignity

[Shad]

I would think it's perfectly fine with the Apollo - if a field of race cars aren't constantly blowing up engines then I'd like to think regular folk that have the same/similar setup and do a few track days are ok

[david nelson]

Thanks for the vid and op reading. I did some logging a few years ago and got similar readings.

 

What video logging system are you using? Is it easy to use?

 

 

[CharlesElliott]

I judge how bad it is based on the outcome. I'm not aware of anyone in our 60+ K series field having an engine go due to 'normal' oil starvation - although we do have catastrophic oil losses due to sump plug loss etc. Having said that, most racers would have the top end rebuilt every 500 - 3000 miles so there is a much higher maintenance regime. My odometer is showing 8,000 miles but my car is on it's third set of valves and has had two head skims/valve seat replacements. Everyone is running forged pistons and updated valve spring caps.

 

I have no technical answer to the Apollo question. My feeling is that pure volume of oil is the main advantage, but have never run without it. There is also a trade off between oil level, safety and performance because a full sump leads to more crankshaft oil thrash and less power, so I run at lower oil levels than most road cars (on the min mark when hot and running).

 

I run a DL1 logging system with Spa senders for oil temp/pressure and water temp. I also have Hall sensors on the rear driveshafts to measure wheel spin. Video is from two cheap DXG HD cameras. Virtual dash is from TrackVision.

 

Charles

[Dignity]

Thanks Charles/ Shad

Reassuring comments

Regards

Dignity

[irrotational]

Very interesting - looking at the video, braking doesn't seem to have *much* affect, is that correct?

 

Would be intrigued to see how the pressure varies with a "full" sump - but i guess you can't really do that in a race!

 

What does 28 psi convert into on the caterham guage of 0-8 bar? Just checked - it's 1.9....

 

At knockhill on the right hander onto the back straight my old-skool dial was dropping to about 1... 😳

[CharlesElliott]

The colour coded map shows pretty well that pressure does not really change in the braking zones. So no, braking isn't a big factor.

[Kevsta]

I'd never thought of buying a cheapo camcorder to video track days like that. Is the camera just bolted to the roll bar with a camera clamp? All this looking into bullit cameras etc. and this is miles easier (and cheap with good quality picture IMO)!

 

Great traces aswell, my OP guage (VDO on a K - for one year without apollo, then with, now DS) I saw as my G meter for Right hand bends 😳 😬

[Roger Ford]

His clamps are worth more than the cameras!

 

[CharlesElliott]

I use Manfrotto super clamps. It doesn't really matter as long as you keep the cameras as solid as possible to avoid shutter roll.

[Rob Walker]

You could fit a Accusump, accumulator, they work well on the exiges I have experience of them on a Cobra as well. I would also fit a mechanical oil pressure gauge and really scare yourself, the electrical gauges are damped and do not show the full pressure drop.

[CharlesElliott]

Personally, I couldn't fit an accusump as it isn't in the race regs.

 

For data logging, I take the output directly from the sender into the data logger so there is no damping there.

 

Personally I don't like mechanical gauges as there is another oil feed running around that is too easy to damage.

 

 

[Alan Bowler]

Charles - do you/other grads racers run with the sump foam or take it out and drill the gasket?

[Roger Ford]

We keep the sump foam in. Arguably it wouldn't be legal to remove it and/or drill the gasket, but even if it was everyone I've talked to (McMillan, Rockey Racing, DPR and RatRace) recommend keeping the foam in on a race car.

[Roger Ford]

Surely if it was a fire hydrant there would be a yellow "H" sign on a wall near it? Or don't they use them anymore?

I wondered what happened to that post...

 

Edited by - Roger Ford on 13 Jun 2013 08:20:34

[CharlesElliott]

As Roger says, foam in. I've been running it for nine seasons, change it ever year and have never had it break down/block anything. It is always in excellent condition (but oily!) when I replace it.