As promised, I have just completed my second dyno test to determine whether the V-6 engine in my 2005 Frontier really makes more power on 93-octane gas than it does on regular. A few weeks ago I ran a dyno test on 87-octane gas for a baseline; next I ran a couple of tanks of premium to allow the ecm to adjust, then I did another dyno test for comparison. For the results and graphs look here: premium vs. regular dyno test
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jack <><
05 Frontier K/C LE 4X2
http://www.reverendbiker.com/frontier/frontier.htm
As promised, I have just completed my second dyno test to determine whether the V-6 engine in my 2005 Frontier really makes more power on 93-octane gas than it does on regular. A few weeks ago I ran a dyno test on 87-octane gas for a baseline; next I ran a couple of tanks of premium to allow the ecm to adjust, then I did another dyno test for comparison. For the results and graphs look here: premium vs. regular dyno test
As promised, I have just completed my second dyno test to determine whether the V-6 engine in my 2005 Frontier really makes more power on 93-octane gas than it does on regular. A few weeks ago I ran a dyno test on 87-octane gas for a baseline; next I ran a couple of tanks of premium to allow the ecm to adjust, then I did another dyno test for comparison. For the results and graphs look here: premium vs. regular dyno test
Actual Real Numbers! Ya gotta love it.
Thanks.
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Jerry
2004 Frontier, King Cab, XE, 4x1, 4-cyl, 5-spd My Frontier Page
That makes no sense... perhaps the ECU didn't advance timing for the premium fuel?? I have no idea...
Joe.
To tell you the truth, it doesn't surprise me all that much. I've had considerable experience with ecm-controlled vehicles that would back off the timing when a lower-octane fuel was used, but I've never seen the reverse. It appears that Nissan has tuned this engine to achieve at least 265 crank HP (and that looks to be conservative) on 87-octane fuel, and the use of premium won't make a big increase in performance.
I've run many dyno tests on cars and bikes, and I know that there is a margin of error. Correction factors help, but no test is exact. Even assuming that the first test was high and the second test was low, the difference between the two would be very small. My truck runs great, with no sign of knock, on 87-octane gas. If I could pick up 10 RWHP by using premium I might consider shelling out an additional $4 per tank, but for results this close I'll be buying the regular stuff and snickering at the 2005 Tacoma owners.
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jack <><
05 Frontier K/C LE 4X2
http://www.reverendbiker.com/frontier/frontier.htm
Good work.
I disagree with your conclusions, though.
To me it looks like there are significant horsepower gains down at the low end--10 whp at 3500 and even more between there and 3750. I have an automatic and that's where I do most of my driving. To me that's definitely worth it. I mean a $100 intake can get you maybe 5 whp and an exhaust costing several hundred maybe another 5 hp?
To each his own, I guess.
Good work.
I disagree with your conclusions, though.
To me it looks like there are significant horsepower gains down at the low end--10 whp at 3500 and even more between there and 3750. I have an automatic and that's where I do most of my driving. To me that's definitely worth it. I mean a $100 intake can get you maybe 5 whp and an exhaust costing several hundred maybe another 5 hp?
To each his own, I guess.
I probably didn't do a very good job of explaining the testing process. You might notice on the graphs that there are no readings below 3300 RPM, and the readings weren't very accurate before 3700 RPM. Auto trans vehicles are just more difficult to test, and since we tested in third gear we had to roll-on really slowly and easily below 3700 to keep it from downshifting and ruining the reading. Above 3700 we could pretty well let the hammer down all the way to 5750, where it shut down. By the way, at that point the rev limiter didn't shut us down but the speed limiter was at 107-108 MPH and that was what kicked in. Believe me, there were no real advantages for the 93-octane tank in the 3500-3750 RPM range. Even if there were, I can't see that a performance enthusiast would pay premium prices to get even 10 HP in such a narrow power range.
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jack <><
05 Frontier K/C LE 4X2
http://www.reverendbiker.com/frontier/frontier.htm
I'm with you now. I always wondered if it was possible to dyno an automatic.
Possible, but more difficult. My last truck was a 5-speed--just work it up to 4th, then stand on the throttle. You get a much cleaner graph and more accurate readings on the low end. We tried a run in 2nd gear but it compacted the graph too much. To tell the truth, I'd like to see how much low-end torque these VQ engines have. By the way, you're a neighbor--I'm up in Georgetown.
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jack <><
05 Frontier K/C LE 4X2
http://www.reverendbiker.com/frontier/frontier.htm
No kidding? I work in Austin but I actually live right up here in Cedar Park. Where do you go to get on the dyno?
I have my dyno work done at Colvin Automotive in Austin. They are nationally known, and were recently featured on an edition of "Overhaulin" when they helped build and dyno-tuned a 1970 GTO for Lance Armstrong. Their dyno operator, Daniel is an ace and has done many tests for me. It's worth going to their shop just to drool over the exotic and performance cars in the garage.
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jack <><
05 Frontier K/C LE 4X2
http://www.reverendbiker.com/frontier/frontier.htm
I think the advantages with premium fuel will be more evident in the real world though. Most dyno tests are done with the hood open and lots of cool air flowing into the engine bay. In the real world the hood is closed, and summer temperatures can really get the under hood temperatures up there. When you have high ambinet temperatures you're more likely to get detonation (spark knock) - causing the ECU to redard the timing advance to eliminate it when it detects it via the knock sensors. Of course, that will reduce HP.
In other words, the advantage of premium fuel may not show up until it's 75F+ outside and the engine is subjected to stop and go traffic.
Heath
__________________ 1997 Nissan XE Truck - 133,000 Miles
1990 Infiniti Q45 - 91,000 Miles
2005 Infiniti G35 Sedan - 34,000 Miles
I think the advantages with premium fuel will be more evident in the real world though. Most dyno tests are done with the hood open and lots of cool air flowing into the engine bay. In the real world the hood is closed, and summer temperatures can really get the under hood temperatures up there. When you have high ambinet temperatures you're more likely to get detonation (spark knock) - causing the ECU to redard the timing advance to eliminate it when it detects it via the knock sensors. Of course, that will reduce HP.
In other words, the advantage of premium fuel may not show up until it's 75F+ outside and the engine is subjected to stop and go traffic.
Heath
Actually, just the opposite occurs. One of the problems with dyno testing is that successive runs tend to show less power because the engine gets hotter and the cooling fan in an enclosed area just doesn't cool as well as does real-world driving. Underhood temperatures have little or nothing to do with the ecm--it gets 80% of its information from the MAF, which draws air from the outside of the engine compartment. I realize that many people desperately want to believe that using higher octane fuel will add performance to an engine designed to operate on regular, but the fact is that there is absolutely not a shred of evidence that shows it to be true.
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jack <><
05 Frontier K/C LE 4X2
http://www.reverendbiker.com/frontier/frontier.htm
dyno conditions could also make the small difference...
did you run a couple tank fulls before testing?
I have to question the results...weather that's due to methods, dyno procedure, or the vehicle. not sure.. But it's been shown time and time again higher octanes like 92/93 octane will produce higher numbers than rock bottom 87 octane and even higher returns on race octanes like 100+.
Now of course these differences are highlighted in high performance platforms...
Even if you throw all that out and call it a draw for conversation... Then the premium grade is still better due the refinement process... a lot less particular matter like gums etc... over the long run it makes a big difference.
Also you can't measure MPG on the Dyno
Last edited by myoung : Mar 18th, 2005 at 02:15 PM.
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