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Discussion Starter · #1 · (Edited)
Anyone ever do tuning on a Dynojet in a lower gear to match acceleration rates record from the car for tuning purposes?

Inertia dyno tuning (or an eddy current type that can match sweep rates to measured in car) really interest me in terms of getting what we're really after, an engine that accelerates better. Thoughts?

Here is where Honda used a 2000rpm/s sweep rate based on measured in-race data to develop their IRL engine to a restricted LMP2 IMSA engine plus another test outlined in the paragraph:




Font Rectangle Slope Parallel Screenshot


Note: an AVL type dyno would be preferred with data acquisition inputs, especially due to the effects of gravity (hill road race courses) and aero being non-linear.
 

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Bob,
I don't know if Mike Laws is a member here. I do know he is a member on Speed Talk. The best I can remember the engine dyno that they had they could do much of this like 15 years ago. It has been sometime since I last talked with Mike. But over the years he was very willing to talk about it.

Stan
 

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Anyone ever do tuning on a Dynojet in a lower gear to match acceleration rates record from the car for tuning purposes?

Inertia dyno tuning (or an eddy current type that can match sweep rates to measured in car) really interest me in terms of getting what we're really after, an engine that accelerates better. Thoughts?

Here is where Honda used a 2000rpm/s sweep rate based on measured in-race data to develop their IRL engine to a restricted LMP2 IMSA engine plus another test outlined in the paragraph:




View attachment 298833

Note: an AVL type dyno would be preferred with data acquisition inputs, especially due to the effects of gravity (hill road race courses) and aero being non-linear.
The posted part of the article didn't mention if the port size had any effect on engine output in this rpm range. Did output go down with the smaller port as exceleration went up or versa visa?
 

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Discussion Starter · #4 · (Edited)
The posted part of the article didn't mention if the port size had any effect on engine output in this rpm range. Did output go down with the smaller port as exceleration went up or versa visa?
Thanks, Warp. I was hoping you would chime in.

I use to think the Revolution type inertia dyno was the way to go and shared their white paper somewhere, where they showed certain manifolds made more water brake dyno power but accelerated slower, and you had commented on that. The Honda paper was incomplete in terms of final results, so that wasn't shared.

I know you have said dyno power typically does correlate improved acceleration (assuming your dyno sweeps look anything like what we are doing). Just trying to find that balance without having to pay or find access to an AVL type dyno, especially for final tuning purposes. Application is a road race application.
 

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Discussion Starter · #5 ·
The posted part of the article didn't mention if the port size had any effect on engine output in this rpm range. Did output go down with the smaller port as exceleration went up or versa visa?
Warp,

They graphed output on the right columns. Fig. 10 is % difference of torque for the inlet ports, Figure 11: is % power gain/loss for camshafts. Figure 9 is response time. % difference were 2000rpm/sec sweeps.

I do think graphing changes vs. a baseline as a % difference is super revealing, and it's how I look at everything now.
 

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Warp,

They graphed output on the right columns. Fig. 10 is % difference of torque for the inlet ports, Figure 11: is % power gain/loss for camshafts. Figure 9 is response time. % difference were 2000rpm/sec sweeps.

I do think graphing changes vs. a baseline as a % difference is super revealing, and it's how I look at everything now.
Had to save to my phone, but can see it now.
Thanks
 
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