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HPTuners Calculated Horsepower Accuracy and Dyno Results. NICE!!!
So I went to the dyno the other day for the first time. I had the car pretty dialed in with a street tune. I just wanted to see what kind of timing it really liked and try different AFRs to really get the last bit of power out of it. Plus I just thought it would be fun to tune my own car on the dyno, having never done it before.
I had always used HPTuners 'Delivered Engine Torque' to tune with on the street, just using it as something to go off of. I made a custom horsepower math parameter and logged that too. I never really thought it would be entirely accurate, but at least I had something to go off of. Well, I left these parameters open when I was tuning the car and what do ya know? It actually works pretty well.
First pull I got 406 hp at 6000 and 39X torque at 4700 rpm.
Dyno: 406/39X HPTuners: 423/414
Next good pull was 418 hp and 412 ft lbs after adding some timing
Dyno 418/412 HPTuners: 427/421
Last good pull with just a little bit more timing up top 421hp and 413 tq
Dyno 421/413 HPTuners 431/421
So overall it looks like HPTuners is quite accurate when using the Delivered Engine Torque parameter to tune with. However, the HP numbers in HPtuners continued to climb as far as I would rev it, while the dyno numbers started to flatten out and drop off past 6000, although if you look at the graph they dont drop quickly at all. So, maybe if you had a combo that dropped off of a cliff after a certain RPM it would show that better.
Also, Im really pumped with the dyno numbers. Seeing as how I built the whole car by myself in the garage on jack stands. From building the motor, porting the heads myself, tuning the car, you name it and it was me who did the work. And for a smaller 226/232 cam and a factory intake i was happy with the numbers for sure. It was a blast to tune a car on the dyno and make the pulls myself.
Well it seems to work pretty well with a H/C car on a speed density tune. Just dial it in on the street and get your VE and such good and straight. I just thought id share and maybe someone would find it useful. Thanks
Good numbers. What were the SAE numbers? Should be about 4% lower... which makes HPTuners less accurate...
And the Cellmass and Dyn Airflow are better indicators of power. The more g/sec you pump through and the higher the cellmass for a given engine, the more power it will make. Also, Cellmass follows the torque curve pretty much to a T.
Good numbers. What were the SAE numbers? Should be about 4% lower... which makes HPTuners less accurate...
And the Cellmass and Dyn Airflow are better indicators of power. The more g/sec you pump through and the higher the cellmass for a given engine, the more power it will make. Also, Cellmass follows the torque curve pretty much to a T.
I didnt get the SAE numbers. I wasnt really up to speed on dyno correction factors until I looked up what "STD" meant when I saw it printed on the sheet. I knew there were correction factors, but not which one I should use.
I guess ill do some research on this other method of calculating power with HPTuners.
Yea.. that **** doesn't work when the injector data/airflow data is off, scaled tune, etc.
If you have accurate injector and airflow data in your tune, the calculation of hp and torque in HP Tuners works just as good as in a stock tune. I just recently confirmed that on a dynojet, very close match of numbers and curves
I have been wondering how close-ish this was. I seen the how to set up on you-tube, and followed that. I still think my setup is low via HP Tuners for some reason, and have been trying to figure it out. I have the cyl airmass #'s, just haven't looked up what to do with those to calculate HP or torque.
I have been wondering how close-ish this was. I seen the how to set up on you-tube, and followed that. I still think my setup is low via HP Tuners for some reason, and have been trying to figure it out. I have the cyl airmass #'s, just haven't looked up what to do with those to calculate HP or torque.
I never used the calculated HP and TQ numbers in HPTuners to tell me what the car made. I only used them to see what changes in the tune had a positive affect on power. I used Delivered Engine torque on the street and picked a stretch of road to do all my pulls. I would start at 3000 rpm in 3rd and wait until i passed a certain mail box and then floor it. This way the pulls would be consistent. The Delivered Engine torque always seemed to go up when the car felt the strongest, so I tested it on the dyno and it does actually go up when the engine makes more power. Even by just a few hp/tq, which I thought was pretty neat.
I wasnt trying to say that HPTuners was dead on accurate for telling me what the car made to the wheels, just that it was pretty accurate at measuring gains from changes in the tune. Specifically spark changes and Power Enrichment changes, which is mainly what I changed on the dyno.
If you have accurate injector and airflow data in your tune, the calculation of hp and torque in HP Tuners works just as good as in a stock tune. I just recently confirmed that on a dynojet, very close match of numbers and curves
Yep the numbers were pretty close, but the gains were most impressive to me. HPTuners Calculated Engine Torque went up/down with the dyno readings. Meaning you can use it to tune spark/power enrichment on the street and be reasonably sure that you are making headway. Big money saver if you ask me.
Yeah, I completely understand what you were saying. I knew it wouldn't be just like a dyno. I also use it for the same purpose. I however wasn't smart enough to pick a specific spot, so I could use almost exact same data. I was using it more for peak Tq #'s on timing.
What injectors are you using? Are they the white GTP 36/42# or the Ford 42#?
Yeah, I completely understand what you were saying. I knew it wouldn't be just like a dyno. I also use it for the same purpose. I however wasn't smart enough to pick a specific spot, so I could use almost exact same data. I was using it more for peak Tq #'s on timing.
What injectors are you using? Are they the white GTP 36/42# or the Ford 42#?
Yes they are the white GTP injectors. Work like a charm! About 72% Duty Cycle T 6700rpm with this power/combo and a racetronix pump/hotwire kit for those who are interested.
I am curious, are any of your VE #'s over 100%? I have the white GTP injectors also. I found the data for them, on here. at 95kPa, my VE goes to 106. I have read a ton about it, and basically the only thing I can find, is either wrong data for the injectors, or a fuel pressure issue. I have good, known fuel pressure. I can't seem to find any other data, that reflects anything different than what I have.
I don't have any "issues" with my tune, or driveability, just curious/concerned about my high VE #'s. I would love to take a look at your tune vs mine, as our builds are very sililar. LQ4, same ported heads, almost the same duration on the cam, not sure on your lift, same intake. You have a M6 vs my 4l65e.
I am curious, are any of your VE #'s over 100%? I have the white GTP injectors also. I found the data for them, on here. at 95kPa, my VE goes to 106. I have read a ton about it, and basically the only thing I can find, is either wrong data for the injectors, or a fuel pressure issue. I have good, known fuel pressure. I can't seem to find any other data, that reflects anything different than what I have.
I don't have any "issues" with my tune, or driveability, just curious/concerned about my high VE #'s. I would love to take a look at your tune vs mine, as our builds are very sililar. LQ4, same ported heads, almost the same duration on the cam, not sure on your lift, same intake. You have a M6 vs my 4l65e.
I just 6 speed swapped the car, and didn't change any VE values. It used to have a 4L60E trans. I know my VE goes above 100 in several areas across the curve. I do believe i see 110% for one or two cells in the table, right at 95 kpa just as you describe.
From what understand this is completely normal in any setup. Volumetric Efficiency just measures how much air goes into the engine vs. its displacement. So around peak torque, where an engine is most efficient, you will commonly see over 100% VE in a NA engine. This of course is assuming that your VE is correct and that it lines up with your Power Enrichment values.
Thanks for the reply. Well it makes me feel a little better that yours is the same as mine. Everything I read, says it "shouldn't" go over 100 in the VE, because you can't fill the cylinder 100% N/A. I don't know. I mean, mine runs pretty good, and like I said, I don't have any issues.
Do you know what the other specs on your cam are? Yours is defiantly making more power than mine. I suspect mine is low because of the "turbo" speced cam I am running. I am sure it would pick up if I had say a LS3 or Tick Polluter in it. I hope to have some boost on it soon though.
Thanks for the reply. Well it makes me feel a little better that yours is the same as mine. Everything I read, says it "shouldn't" go over 100 in the VE, because you can't fill the cylinder 100% N/A. I don't know. I mean, mine runs pretty good, and like I said, I don't have any issues.
Do you know what the other specs on your cam are? Yours is defiantly making more power than mine. I suspect mine is low because of the "turbo" speced cam I am running. I am sure it would pick up if I had say a LS3 or Tick Polluter in it. I hope to have some boost on it soon though.
The cam is a Howards 226/232 112+4 580 lift, if i remember correctly. I might be off on the lift by a tad, i remember it was a lower lift compared to most these days. It is advertised as "Aggressive Street/Strip, Mid torque & horsepower, Needs good heads." And it definitely delivers on that.
Im sure the valve events are quite different since yours is advertised as a 'blower/turbo' cam or whatever. There's a lot more to camshaft specs and design than lift,duration, and LSA. But, I was really surprised on how much torque the cam makes throughout the RPM range. Super fun to drive on the street. My tires hate this cam
So I did find some "missing HP". I noticed while WOT, my map would drop from ~105Kpa to ~95Kpa. I have a 4" inlet tube and a 12" K&N filter. My exhaust is dual 2.5" all the way out mandrel bends, so I figured it "should" support the HP it should make. Turns out, it seems under the hood must be closed up enough, it would draw a vacuum of some sort. I knew my IAT's were high, and I was working on that, well I drilled 5 1" holes in the inner fender of the passenger side, and really helped 2 birds with 1 stone. The IAT's went down, and the Kpa stays @ 100 now. This was really surprising to me that it was that choked for air. HP Tuners showing in the high 420's now.
What's the setup to use DelTq, CylMass and/or DynAir to optimize spark on a F-body? I presume you're using a histogram...what axis's? What PID(s)?
I tried setting up three MAP vs RPM tables and respectively populating DelTq, CylMass & DynAir. The DelTq table seemed to populate correctly but the cell hits in CylMass and DynAir seemed to keep resetting to zero... not much data there.
08-17-2017, 06:34 PM
HPTuners Calculated Horsepower Accuracy and Dyno Results. NICE!!! 
