GC vs M1 on dyno

[NewC6]

Over at CorvetteForum, there is a post where an owner did a test running his vette on a dyno using M1 then GC. GC seems to give a little HP hit.
http://forums.corvetteforum.com/showthread.php?t=1576348

So what say you?

 

[JAG]

That's what I'd expect. GC has higher HTHS viscosity and kinematic viscosity at 100C. It's not much difference though...~1/2%. The poster wrongly thinks that M1 5W-30 is thicker.

 

[buster]

I agree with JAG. Maybe Patman should try M1 again. Wear metals would be higher, but in the long run I'm not sure you would have the car long enough to even notice.

 

[Patman]

I'll never run M1 in my Corvette but I would consider running Redline 5w30 or PP 5w30.

I don't trust dyno numbers too much as I've seen my own car vary by 10rwhp on the dyno from one run to the next just due to different coolant temps.

All I know is that my car runs extremely good in the quarter mile for only having two mods on it (it's run a best of 12.81 at 109.4, with just a Vararam cold air kit and dyno tuning)

 

[gtx510]

I was expecting a bigger difference in whp than that.
Let's see a UOA of those oils.

 

[Reg# 43897]

Yeah, dyno's are just too inconsistent for such comparisons. I would put much stock in it, myself.

John.

 

[Turbodriven]

You should try find a tuner with one of these...
http://www.dynapack.com/dynapack.html

The greatest inconsistency with the conventional dyno is the tyre to rollers. Temperatures affect the grip of the tyres and these change on the run, so if this is eliminated then you are more likely to have a more stable set of figures.
We have a well known and trusted Scoobie tuner here in SA that uses a Dynapack very successfully.

 

[KBFXDLI]

M1 is definitely NOT thicker...you can run it in a Honda engine that specs 5w20 and the 5w30 runs the same as the 5w20 after it has about 100 miles on it.

 

[outersquare]

.7% difference, less than one percent. Like anyone would notice that, especially in a 500+ WHP car.

 

[gtx510]

but doesn't GC have a larger mpg drop than that when compared to M1 5W30?

www.rototest.com even better dyno, used by car manufacturers
Dyno Dynamics and Mustang are good too but they're still roller dyno's. They are more accurate than Dynojet but if he's getting consistent numbers that does say something.

 

[Greggy_D]

Quote:

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I don't trust dyno numbers too much as I've seen my own car vary by 10rwhp on the dyno from one run to the next just due to different coolant temps.

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Agreed.

 

[kcryan]

Quote:

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M1 is definitely NOT thicker...you can run it in a Honda engine that specs 5w20 and the 5w30 runs the same as the 5w20 after it has about 100 miles on it.

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Right....or not so much

 

[biomed_eng_2000]

One thing that I don't like is that all of rototest's dynos only have only about 15 points of rpm data (Why so few? Are they hiding their resonance problems?):
http://www.rototest.com/performance-graphs/graphs.php?Visitor=1&DN=33

See possible resonance problem as evidenced by spikiness in the dyno graph:
http://www.flyinmiata.com/tech/dyno_runs/1996_FM_II_Link_new.pdf

Quote:

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but doesn't GC have a larger mpg drop than that when compared to M1 5W30?

www.rototest.com even better dyno, used by car manufacturers
Dyno Dynamics and Mustang are good too but they're still roller dyno's. They are more accurate than Dynojet but if he's getting consistent numbers that does say something.

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[gtx510]

Ok, I think I get what you mean by resonance problems. Could that be from drivetrain vibrations that are no longer being dampened by the tires? I wonder how OEM's are getting around this issue?

And I'd never noticed the rpm datapoints that you mention. The Dyno Dynamics dyno that I played with could "snapshot" data tables in 25rpm (or 50rpm?) increments. I thought the Rototest also could? The dyno sales guy/tuner even said Rototest was the most accurate, to the point where tapping on the hubs could affect the readings. Maybe that explains the spikey Flyin Miata graph?

I think it'd be interesting to see tests like this, on a variety of engines, that also did VOA/UOA's and measured coolant, oil, driveline, ambient and intake air temps, tire pressure/temp, etc.
If the car was strapped to a chassis dyno I'd almost like to see the oil being changed without the car being undo, just to make everything equal.

Dynojet's should be able to give repeatable, "accurate" results. You just need to figure in the 20% "fudge factor" if you want a "true" whp #.

 

[Lonnie]

Repeat after me, "Dynos are for trends, tricks are for kits". I've worked for years building and changing racing engines on a viscous sheer dyno that told us how one run compared with another run and we never claimed to have a certified torque reading or converted anything to a hp figure that could be taken as the answer to the question, how much hp does this engine product. It all worked and we were able to develop induction systems, exhaust system, pistons and all kinds of stuff. Sometimes when we would have great success with a setup we would take it to another dyno for a bench mark but we never suffered from horsepower envy.

 

[gtx510]

huh?