Japshow Saturday, an interesting experiment!

[oilman]

Saturday at Japshow (Santa Pod) was a HOT day! Ambient and track temps were very high as those of you who were there will have experienced!

 

We were approached on our trade stand by a bunch of scoobie owners who were looking for advice on the oils they were using. One of the owners of an STi WRX 02 was running 15w-50 and looking to do a change after the morning session having run no better than 13.8secs on the strip .

 

After a long discussion about oil viscosity and oil temperatures (which incidentally never exceeded 110degC even that morning) he decided to take our advice and try 5w-40 instead to see whether he could gain more BHP at the wheels simply by running on an oil that had lower drag.

 

They were large blokes (nice with it though and I was totally outnumbered) and agreed to revisit me at the end of the day with their findings. Worried? No not really but curious about the outcome!

 

So, the afternoon came and went and I thought no more of it.

 

At around 4.00pm they showed up back at the stand. Happy? Delighted and totally speechless! His best time on the 5w-40 was actually his personal best and by far the best of the day with comparative reaction times it was a 13.1!

 

So, 13.8 to 13.1 just by changing the oil

 

I know these guys frequent Scoobynet and SIDC so hopefully at some point they'll post their own side of the story but, just goes to show that the figures don't lie and there is always room for improvement when you have the most suitable oil in the engine.

 

Just thought this may be of general interest as it was an experiment on a day when conditions were harsh and in a very real situation.

 

Cheers

Simon

[SimonR]

Apart from the obvious "it's thinner", can you expand a bit on why a lower viscosity would have made so much difference please?

[oilman]

It's simply down to oil drag. 5w-40 is 14cst at 100degC and 15w-50 is 18.5cst at 100degC, 10w-60 is 24cst at 100degC.

 

Modern turbocharged engines only need around 10-14cst.

 

So long as the oil temperature is not above the oils limitations then thinner is always better!

 

If only I could have convinced him to run PRO R 0w-20 for the afternoon!

 

Cheers

Simon

[SimonR]

You could have convinced me! I was ready to try anything on Saturday after I couldn't get under 14 secs.

[oilman]

Should have come to see me mate, I was in the pit as usual!

 

This was the basis of what we tried and to some extent proved

 

Must Have MORE Power!

 

Motorcars are bought for all sorts of reasons, but enthusiasts like lots of power. To get more power, a lot of fuel must be burnt, and more than half of it, sadly, gets thrown away as waste heat. For every litre of fuel burnt, 60% of the energy goes as waste heat into the exhaust and cooling system. A turbocharger can extract a few percent as useful energy and convert it into pressure on the intake side, but only 40-45% is left, and only 25% actually shows up as BHP at the flywheel.

 

6% goes in pumping air into the engine, 6% as oil drag losses and 2-3% as engine friction.

 

The oil deals with 97% of the friction; so reducing the remaining few percent is not easy.

 

If you doubt that even ordinary oil has a massive effect, take a clean, dry 200 bhp engine, connect it to a dyno and start it up. It will only make 1 bhp for a few seconds. Now that’s real friction for you!

 

Oddly enough, people get starry-eyed about reducing friction, especially those half-wits who peddle silly “magic additives”, which have not the smallest effect on friction but rapidly corrode bearings and wallet contents. In fact, even a virtually impossible 50% reduction in the remaining engine friction would be no big deal, perhaps one or two bhp or a couple of extra miles per gallon.

 

Even More Power!

 

He place to look for extra power is in that 6% lost as oil drag. In a well-designed modern motor, the oil doesn’t have to cover up for wide clearances, poor oil pump capacity or flexy crankshafts, so it can be quite thin. How thin? Well take a look at these dyno results.

 

A while ago now, we ran three Silkolene performance oils in a Honda Blackbird motorcycle. this fearsome device is fitted with a light, compact, naturally aspirated 1100cc engine which turns out 120+ bhp at the back wheel. The normal fill for this one-year-old engine was 15w-50, so the first reading was taken using a fresh sump-fill of this grade. (The dyno was set up for EEC horsepower, i.e. Pessimistic)

 

15w-50

Max Power 127.9 bhp @ 9750 rpm

Torque 75.8 ft-lbs @ 7300 rpm

 

After a flush-out and fill up with 5w-40 the readings were;

 

5w-40

Max Power 131.6 bhp @ 9750 rpm

Torque 77.7 ft-lbs @ 7400 rpm

 

Then we tried an experimental grade, 0w-20 yes, 0w-20! This wasn’t as risky as you may think, because this grade had already done a season’s racing with the Kawasaki World Superbike Team, giving them some useful extra power with no reliability problems. (But it must be said, they were only interested in 200 frantic miles before the engines went back to Japan)

 

0w-20

Max Power 134.4 bhp @ 9750 rpm

Torque 78.9 ft-lbs @ 7400 rpm

 

In other words, 3.7 bhp / 2.9% increase from 15w-50 to 5w-40, a 2.8 bhp / 2.1% increase from 5w-40 to 0w-20 or a 6.5 bhp / 5% overall. Not bad, just for changing the oil! More to the point, a keen bike owner would have paid at least £1000 to see less improvement than this using the conventional approach of exhaust/intake mods, ignition re-mapping etc.

 

Cheers

Simon

 

 

ANYONE for 0w-20 for a session?

[michael]

I can knock fractions of a second off my 1/4 by improving my driving - what's to say he didn't do the same?

 

The oil may have helped but I don't think you can put it all down to that alone, there are far too many factors involved.

[JohnA]

If you use 0w0, will it keep idling forever?

 

[oilman]

I can knock fractions of a second off my 1/4 by improving my driving - what's to say he didn't do the same?

 

The oil may have helped but I don't think you can put it all down to that alone, there are far too many factors involved.

 

I totally agree with what you're saying. The only way to prove it is to try it I guess

 

Cheers

Simon

[Gaz Walker]

I can knock fractions of a second off my 1/4 by improving my driving - what's to say he didn't do the same?

 

The oil may have helped but I don't think you can put it all down to that alone, there are far too many factors involved.

 

Exactly... with a poor ET you can make 0.5s-1s difference.

 

Gaz.

[toyo rob]

i take it 0W-40 would be slightly better than the 5w-40 readings??

and what sort of increase is the 0W-20 from that, similar would be a guess?

 

cheers

 

Rob S

 

ps need more mods and exp before oil becomes a factor in my times, last reaction was about a sec?!?!

[oilman]

i take it 0W-40 would be slightly better than the 5w-40 readings??

and what sort of increase is the 0W-20 from that, similar would be a guess?

 

cheers

 

Rob S

 

ps need more mods and exp before oil becomes a factor in my times, last reaction was about a sec?!?!

 

The second number is more important so gains would be based on the higher number being lower if you see what I mean. sae 30 and sae 20 would give gains over sae 40.

 

15w-50 to 0w-20 is reckoned to be 5% at the wheels.

 

Cheers

Simon