Using the "HP" Calculated field in MLV

[Captain Bondo]

Who's using it? I haven't seen it mentioned much, but I have found it to be extremely useful, quite repeatable, and somewhat accurate.

I say somewhat accurate because I altered the vehicle weight from the actual in order to get the plot to match my dyno results. This results in an entered weight of 3500lb. Actual weight with me in it is 3300lb.

You sometimes need to take the plots with a grain of salt, as the calc is sensitive to RPM noise, but generally mine are clean-ish.

Here are a few examples to help explain why I find them useful.

Here's a typical 12psi pull, from before I did the 960 cams, and when I had the crappass VB921's.

Power peaked pretty much at 5000rpm (when I hit full boost) and the just dropped from there. It's also a bit raggy partially becuase of the weak spark.

An important point with a log like this: When it's rough like this, you kinda have to cross your eyes some. DON'T LIE TO YOURSELF. What's happening is MS is missing a couple counts, so it thinks there was less accel, then when it stops missing them it thinks there was more accel. The peak HP isn't going to be at the peaks, you need to draw an imaginary best average through the rough spot. Depending on your rpm signal some pulls might be to rough to really use.


Yellow is RPM, Light Blue is manifold Pressure in kpa, Purple is power in hp.


http://i289.photobucket.com/albums/ll214/WatsonFab/tuning/hpold.png




Here is a pull with the new cams and new ignitors at similar boost:

http://i289.photobucket.com/albums/ll214/WatsonFab/tuning/hpnew.png


I should have adjusted it in the X to have the same sime scale.

Anyways you can see the graph is smoother, and the power curve reflects the hotter cams appropriately.


This sort of comparisons back-to-back can help you get an idea for what sort of AFRS you motor like, and also evelaute timing map changes to some degree (bordlerine not accurate enough for that).


Here's a plot of me trying to run 16psi and failing miserably:

http://i289.photobucket.com/albums/ll214/WatsonFab/tuning/miss.png


Now I can review where it dropped out, overlay batt V, AFR, etc on top and it's a good troubleshooting aid.

Without the HP plot it's less clear where the dropout actually occurred.

Anyways I think it's a slick feature to help you analyse the "character" of your motor- although you need to keep yourself honest with it which can be hard.

Anyways hopefully someone finds this useful/helpful/interesting.

[arsenix]

I've always thought engine speed logging could be a useful way to tune given a nice "track" to test on :)

I assume you adjust the weight to match your wheel dyno results? Based on what I've read I think 10% is probably a not unreasonable error for most tuning shop dynos.

I actually installed an ABS wheel speed sensor on one of my front wheels to play around with logging wheel speed data... haven't had a chance to do much with it though. I figured monitoring a front wheel would get rid of any wheel spin issues and I could log actual road acceleration as well.



James

[Captain Bondo]

Yeah exacty - that's what I did, and I agree 10% is not much.

The only odd thing is I had to add 10% to match the numbers given by a notoriously stingy Mustang dyno, (so number that as far as dyno numbers go, are typically low to begin with) so it might read slightly low. I don't think the calc takes Cd into account for example. But I was immediately impressed it was that close right off the bat.

Yeah there is a "VSS HP" field as well but I haven't played with it- the nice thing is that you don't need to re-load and recalculate for pull done in different gears. I pretty much just do pulls in 3rd anyways though. Limited traction in 2nd and 4th is too fast.

Another thing that is probably obvious but should be remember is try to do pulls on a flat section of road.

[kildea]

i also found is very useful in tuning, in particular when i was controlling the cam since that required so much time it would have been tough to really do it by the just driving around it was nice to be able to see where things started to hurt the tune in some sort of quantitative-ish way.
the difficulty for me was that once it started working nicely i had no real-world comparison, so although i found my peak power nearly doubling between the initial runs with poi's tune and the final runs with the new turbo, intake plumbing, cam control, and tuning, i still had no idea of how it compared to a stock t6. using the same numbers, and 4th gear pulls i went from seeing "250" to "450" during this whole process, but beats me what the numbers really represented.
i did find it to be a pain to have to do the tuning on the highway, since once the tune started to come together i couldn't get useful numbers when in 2nd or 3rd gear due to wheel spinning. and my favorite tuning spots really are the 50mph speed limit roads near my house, but i did find it to be great feedback anyways, i felt like i was doing some actual good when i saw the numbers rising.

[Captain Bondo]

the difficulty for me was that once it started working nicely i had no real-world comparison, so although i found my peak power nearly doubling between the initial runs with poi's tune and the final runs with the new turbo, intake plumbing, cam control, and tuning, i still had no idea of how it compared to a stock t6. using the same numbers, and 4th gear pulls i went from seeing "250" to "450" during this whole process, but beats me what the numbers really represented.


Now THIS is why I really like the feature. Say you were doing your tuning now.

We know the gearings of our 2 cars, and we know the weight is within 100lbs. And MLV using the same calcs internally.

So, we have effectively crossed the boundary and eliminated unknowns based on things like dyno calibrations.

If I dyno my car and then compare it to Peter's dyno- is it telling me anything? Honestly, I have no idea.

But, assuming we both drive on a flat road, and we both use appropiate gearing/weight/tire size inputs, the numbers should correlate, so at some point if everyone keeps doing this, we will have historical data and a very strong system for comparative purposes and crosschecking our results based on others' experiences.

[kildea]

But, assuming we both drive on a flat road, and we both use appropiate gearing/weight/tire size inputs, the numbers should correlate, so at some point if everyone keeps doing this, we will have historical data and a very strong system for comparative purposes and crosschecking our results based on others' experiences.

this is the way to do it definitely.

i've got a pile of work to catch up with this month, but i will get some tuning done with the new setup in a few weeks, and when i do i WILL absolutely start posting it... no more excuses :oops:

there's no excuse not to, and it could really make for a good source of info for others.

[Captain Bondo]

this is the way to do it definitely.

i've got a pile of work to catch up with this month, but i will get some tuning done with the new setup in a few weeks, and when i do i WILL absolutely start posting it... no more excuses :oops:

there's no excuse not to, and it could really make for a good source of info for others.

Sweet man. I am glad this makes sense to someone else. My intent was to suggest we start historizing MLV power pull screen shots in a standardized way, but I wasn't sure anyone would see the value.








People could see what different cams do etc, it'd be great.


I wonder If I can use my mod skillz to organize something.


What might make sense is to have people use a fairly descriptive post topic, so that the thread is easy to search.

My car rips at 12psi currently, but it cuts out past that, if I can fix that I am going to re-dyno next week.

Unfortunately I wasn't super impressed with the dyno place I went to, so I will be on a different dyno.

Silver line is it will give a chance to see how my MLV "calibration" compares to a different dyno though, which diversifies the data set I guess.

Planning to go to a dyno dynamics, which should result in numbers lower than Dynojet but higher than a Mustang.

[Captain Bondo]

So nobody's testing anything these days? :-(

I rewired my ignition - hopefully I'll have some good logs later tonight.:x:

[The Aspirator]

Very neat! I've always known about it and checked it after the fact, but never tuned with the HP graph in mind. Does the torque graph seem accurate too?

I haven't tuned my car in like 5-6 months, it reeeeeeeeeally needs it. Not only are there several dead spots in the powerband and response, but I'm only gettin 22mpg all hwy when I used to get 28-32. And the car is pathetically slow, so it needs some lovin.

[Captain Bondo]

Now that I've re-dynoed I am going to check them.

Problem is I have to check them in 4th, as wheelspin really screws the numbers, and testing my powerband in 4th requires lose-your-license type speeds.

My last test showed 340whp @12psi, the car made 365 @ 14.5psi on the dyno (I didn't do a pull at 12psi) so it was accurate up to that point.

[The Aspirator]

I guess the actual number is less of a concern, and it's the curve and the changes in the HP that you're tuning for.

[Captain Bondo]

Correct. What I mean is that I "calibrated" the ms stuff to read 285who when I dyno'd 285whp.

If it is still accurate now that I am making 100whp more, then that suggests that the relative changes are accurate and the calcs work fairly linearly.

[The Aspirator]

That would be just dandy. PS I told Meg today that you went from 240whp (didn't remember that it was actually 285) to 388 and she said "WOAH that's loaaaaaaaaads! Good for him!". Haha.

[Captain Bondo]

That would be just dandy. PS I told Meg today that you went from 240whp (didn't remember that it was actually 285) to 388 and she said "WOAH that's loaaaaaaaaads! Good for him!". Haha.

Haha. What I'll do is datalog the runs at the drag strip on friday. That'll be as close as I can get. Problem is the top of 4th is ~150mph, top of 3rd is wheelspin, so it's freakin hard to test!. :rofl: