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Re: Fuelie on the Dyno
Neat test, Patrick. If the dyno operator tracked air/fuel ratio, how did it look over the RPM range? And what difference did you observe between left bank and right bank?
Jim -
Re: Fuelie on the Dyno
Jim,
Wide range A/F is on the digital gauge in the lower left of the picture. We adjusted the power stop so it was in the 12 to 1 range under hard acceleration and at steady state light load it was in the high 14 low 15 to 1 range with no lean misfire. Hard to read the gauge however as it was jumping around a bit. Only measured on the left side. First time that engine had run since the 1980s. BTW its .020 over with headers and no accessories and race gas. More power than I expected however for a stock motor. I know its good for a few more rpms and a little more timing but it was a new tight motor and I limited the test to 5500 rpm. From your experience will the right side be leaner?
patComment
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Re: Fuelie on the Dyno
The air/fuel gauge is a little hard to see in the video but it looked like the air/fuel dipped into the high 11:1 range fairly often. I don't think there was any high RPM leaning of the mixture..... was there?
In general, the power stop appears richer than it needs to be. I'd re-adjust it for something in the 12.5:1 to 13:1 range. I bet you'll see a slight increase in power as a result.
Your light load mixture looks fine. Even if you run the engine on pump gas, it won't be too lean.
Left and right bank mixtures will be slightly different but my aging brain never remembers which side is the more lean. Jerry B.? Are you reading this? Feel free to save me from my senior moment.
JimComment
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Re: Fuelie on the Dyno
Jim
You are correct Jim its runs a little rich under full power according to that gauge. I am putting a couple of bungs in my down pipes from the stock exhaust manifold to monitor A/F when its back in the car. The car has a stock n-11 exhaust. I plan to do the final adjustments in car along with making sure the drivablity is good. I will probably run the leaded Sonoco race gas in the car just to be safe. It has the stock shim head gaskets so its close to stock compression. My dynos at work make this one look a little archaic. This has been a fun project.Comment
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Re: Fuelie on the Dyno
A couple of comments, not based upon any scientific methods just on trial and error.
Ran my FI at track never got any traction, but top end was 109.? Put about a 50/50 mix of non leaded street gas and
100LL. Next year I ran gas down real low and 3/4 tank of 100LL, best time was 105 top end, so more is not always better.
Stock engine with headers.
As for a reduction in AF down a little, it sure seems to be faster. Again no scientific proof here, just a comment.Comment
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Re: Fuelie on the Dyno
Excellent plan. It's hard to beat real time AFR monitoring under actual driving conditions. If the equipment you'll use provides for a way to data log your AFR, I suggest you take advantage of it. After a test drive, a review of your data will show you events you would otherwise not notice; you can correct problems you can't even feel with the seat of your pants.
FWIW I use equipment from Innovate Motorsports and carry a small netbook for the data logging. (The picture below shows what I used when all I monitored was AFR. Since this picture was made, I've added additional data capture capability.)
JimComment
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Re: Fuelie on the Dyno
Jim, I use a Dynojet chassis dynamometer with a 3,000 pound drum. With new nozzles and a new spider, the A/F ratios are usually within 2% of each other from side to side. Neither side is consistently leaner than the other on any of my engines. Measured at the rear wheels, peak power at full throttle under load occurs with a ~13.1 A/F ratio and 36 degrees of total advance when using a 30-30 cam with stock exhaust.
JerryLast edited by G B.; January 5, 2017, 11:10 PM.Comment
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Re: Fuelie on the Dyno
Excellent plan. It's hard to beat real time AFR monitoring under actual driving conditions. If the equipment you'll use provides for a way to data log your AFR, I suggest you take advantage of it. After a test drive, a review of your data will show you events you would otherwise not notice; you can correct problems you can't even feel with the seat of your pants.
FWIW I use equipment from Innovate Motorsports and carry a small netbook for the data logging. (The picture below shows what I used when all I monitored was AFR. Since this picture was made, I've added additional data capture capability.)
Jim
Jim,
Do you run two wide range sensors at the same time when you are logging data? I have the laptop but will have to set up the interface.
PatComment
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Re: Fuelie on the Dyno
You may have heard that from me. I ran A/F on both sides on the race car and consistently got a leaner condition on the right side with my set up and with the engine dyno setup and with chassis dyno. Each using a different sensor and hardware. i think it has to do with air under WOT coming in and impinging on the right hand internal wall of the plenum. 13.4 A/F with 39 degrees total advance is the sweet spot for my race motor. 30-30 cam and 461 heads, ported and, importantly, relieved.Comment
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Re: Fuelie on the Dyno
jim,
I am not sure yet. We run a number of AVL dynos at work for emissions validation and testing of natural gas vehicle engines. We always run dual channel wide band sensors for our lean burn and stoic calibrations. I am going to talk with my techs and get there thoughts next week. I am afraid however that our dyno data acquisition eqipment is AVL proprietary and too big anyway but we will see what they suggest. In the end I will probably go the Innovate route like you. Seem reasonable and portable. How do you like the data logging software..pretty intuitive? PatComment
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