Foot lbs or Pound ft = torque?
HD EFI Guru
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I'd have to agree with this. It's how I tune without a dyno. Not as accurate by any means but can get you pretty damn close if you have the patience, monitor sensors, reading logs, etc.
It's also why I questioned the whole SAE vs STD correction. The difference is pretty minor given all the ways, intentional or not, that the results can skewed. As much as 30% and more! The question then becomes where to stop so as not to be obvious about it. Even making the initial run look worse than it actually is to make the tune look that much better. Just the fact it's done first will make it worse.
Here's a real eye opener on just what I'm talking about. Even the fact I run conventional oil vs synthetic can cost as much power as the difference between SAE and STD. (3%)
Where sensors for the dyno are located is just one of countless ways.
Well I had a link posted but it won't let me link it and it's way too much to copy/paste in even 2 responses but the ways to skew results are endless.
It's also why I questioned the whole SAE vs STD correction. The difference is pretty minor given all the ways, intentional or not, that the results can skewed. As much as 30% and more! The question then becomes where to stop so as not to be obvious about it. Even making the initial run look worse than it actually is to make the tune look that much better. Just the fact it's done first will make it worse.
Here's a real eye opener on just what I'm talking about. Even the fact I run conventional oil vs synthetic can cost as much power as the difference between SAE and STD. (3%)
Where sensors for the dyno are located is just one of countless ways.
Well I had a link posted but it won't let me link it and it's way too much to copy/paste in even 2 responses but the ways to skew results are endless.
Grand HDF Member
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From: Dubuque, IA
The issue that these Internet Sales guys have spent so much time learning all the ways to cheat the system and then have moved on to finding ways to make the picture look different than what one would typically see has people so confused these days, plenty of people have just said I don't trust any of them anymore. I can honestly say I understand them for feeling that way too. The aspect ratio of a photo can be adjusted to get a line to look dead flat but yet take the same data and run it with a normal aspect ratio and it looks like winter storm season sea's on the pacific ocean! It's not just the couple of percent variation in the Dyno corrections either. The dyno's used in the motorcycle world have NO direct measurement of Torque or Horse Power. They only measure Rate of Acceleration of a drum spinning on bearings! A typical Dyno pull only last about 6 seconds going from 1500 - 6000 RPM in 5th or 6th gear. Trying doing that on the street and see how long it takes! There are plenty of people who don't understand that simple part of it. The engine is NOT making more power in different gears like these thing show! Since your only accelerating the drum on bearings, when you run a higher gear it shows the power rising from a lower gear, now change the air pressure in the rear tire and it shows an improvement in HP and Torque which again is BS. Then add made up corrections outside of the range the correction are designed to work in, and you get what we have today. It's not uncommon to see some dyno graph post here that show a temperature swing of 30 degrees between the baseline run and the after run yet people believe the difference they see on the paper. If you look the data for using the corrects, they have run a baseline below what is allowed and the after run, above what's allow all in the span the same day! This is why I tell people they need to look at the numbers at a give point to compare, to even hope to be able to get some meaningful information from the sheets.
All you can really do is research tuners the same way one would research head porters. The ones that consistently have results seemingly better than others get with the same or similar hardware are most likely cheating the system. Especially when they're dyno tuning their own builds.(namely head work)
Best to have someone other than the builder, that has nothing to gain by cheating, do the dyno imo. But then they MAY cheat it the other direction in attempt to make the build look worse than if they did it.
Partly why I had hrdtail do my tune is it's all he really does and has no interest in any particular builder or making one look better than the next. It is what it is and he does his best with tuning it and the numbers are what they are. I think he was just as surprised as I was at the results in the end but then Don's head work is pretty well known to be top notch. His flow sheets reflect this. And he even text me a week or two later to say he had recalibrated his flow bench affecting my numbers making them 3% LESS. Still way better than most.
My point is, imo, both of them do their best to be honest in what they do and do he best job they can regardless of the numbers or who did what.
However there's some things that are just part of the dyno used that are out of his control too. But these things SHOULD be consistent no matter who's doing it too so...are my numbers a true, real life representation of actual power? Probably not. But then neither are anyone else's. I DO think mine are an honest representation given the tools(dynojet 250i) used tho.
Last edited by 60Gunner; May 1, 2022 at 11:17 AM.
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Stellar HDF Member
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When I started this thread I didn’t realize so many People with so much education would put so much information across the entire thread, I think the moderators ought to make this one a sticky!
Last edited by Harley1004; May 23, 2022 at 02:51 AM.
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From: Boston, MA
rear wheel? You mean orbital toroidal mass, Jane you ignorant ****.
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Stellar HDF Member
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From: WI
Previous post was supossed to say something like,,,,,,,Easy now big guy,,,,,, Do not know how those words were posted,,,dam cell phone voice texting the wrong stuff and posted without screening????????????????????????????????????????? ????????????
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