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supernova_6969

Compare your Dyno sheets HERE

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2 hours ago, supernova_6969 said:

Hey Gollum, NewZed.

Thanks for this;  just a few days ago, i was thinking the same but refrain from bumping my own thread....   

So Gollum, seems that your numbers are similar to stock, but with about 30hp and 30 torques more than stock....

The block, turbo and head are stock, and the boost you're running is low (Stock low, or even less, i think stock is 7psi).. 

You've got better jnjectors but that doesnt add power in these circumstances, and same-ish for ignition (some hp, but not 30!)..

So my question is where is he extra power comimg from?  Is it the MN47 heads matched with the block and piston that give you more compression?

 

And with the nice injectors and nice ignition set up, are you planning on giving it more boost eventually? Seems like your set up csn easily grt to 250-300 whp...

Seb

 

First rule of dyno numbers: Don't compare different engines on different dynos. :-D

 

That said, I did go through the painful work of validating all my data as much as possible for a reason. I even did my own flow testing of the injectors in my garage because I wanted to know that I was giving megasquirt valid data and that my VE numbers would have some similarity if I switched to another ECU or injector.

 

I think 30hp/tq is well within the realm of error factor. For example, if I overestimated the weight, and my curb is actually closer to 2200 lbs, then that would put me at 177 peak.

 

But let's consider some reasons my engine MIGHT make more power than a stock L28ET, which many might think I have no reason to be far above and I wouldn't disagree/argue with said person.

1) I'm running much hotter spark than factory

On that note, I'm also running slightly larger than stock gap, but there just isn't really a comparison here.

2) I'm using an NA cam with the MN47 head.

This might not mean much, especially since my torque is still peaking at 3k. But it's something worth noting.

3) I'm at the ragged edge of detonation on CA premium 91 octane E10.

As I stated. I need to pull timing still and I'm going in and out of detonation in that range. You won't find an OEM tune anywhere as close to so agressive.

4) The OEM tune is pig rich.

Most OEM ECUs are going to land in the 11's during a pull. Nissan ran these engines so pig rich it's rediculous. User stupid_fast was amazed how much more responsive his engine became just taking fuel out.

5) Everything about my combo is minimal.

I have minimal vacuum lines/accessories, I have no power steering, no AC. Anything that can be pulled off, has been. Might be worth a few ponies?

6) Sequential fixes all the things!

That's a lie. I doubt it adds any power. But the engine happily idles and cruises at 14.7:1 :-D

 

I do plan to add more boost eventually, but I'm getting my tune solid first. But I'm also NOT planning on adding an intercooler. I have a flex fuel sense setup already, so when I get my 91 pump gas tune down, I'll switch to tuning E85. I plan to alcohol-proof my fuel system next winter so I can run E85 for longer periods than just tuning sessions, but I do plan to find out what the limit is for this combo without an intercooler and on E85. I suspect reaching the limits of the turbo are well within reason, and eventually I'll upgrade the turbo. In fact, this one leaks a good amount of oil so I've been debating tossing a cheap ebay T3/T4 on there until I spend the money on a nice turbo. Also, if I happen upon one, I'll buy a F54 flat top bottom end to stick under this head, but I also want to get some basic work done to the head as well. I want to fit it with larger valves long with cleaning up the chamber, and blending the bowl area. If all this aligns before I blow something up, I hope to make more power non-intercooled than I've seen anyone else run. But a number/goal isn't really important, it's about the journey and having done something. Hence my lack of desire to argue about above numbers. It could have been 150 and I wouln't care.

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2 hours ago, Gollum said:

 

First rule of dyno numbers: Don't compare different engines on different dynos. :-D

 

I think 30hp/tq is well within the realm of error factor. For example, if I overestimated the weight, and my curb is actually closer to 2200 lbs, then that would put me at 177 peak.

 

 

Are you using one of those accelerometer iphone apps?  They're neat but not sure that they really count for much.  No offense.  Lots of potential error.  Probably good for maximizing a tune but the power numbers will be suspect.

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47 minutes ago, NewZed said:

 

Are you using one of those accelerometer iphone apps?  They're neat but not sure that they really count for much.  No offense.  Lots of potential error.  Probably good for maximizing a tune but the power numbers will be suspect.

No, I'm using VirtualDyno with the source being megasquirt logs. I actually trust the reality of the numbers LESS than a good GPS and accelerometer based solution, but this has some serious known consistency going for it. I could get MS logs from someone else and as long as I know their vehicle data get very comparable numbers. Arguably more comparable than dynos of the same make/model in different locations.

 

Eventually I'll have a 10htz gps in my car and I'll also have power logs from tunerstudio. The power logs I'm currently getting from shadowdash are.... iffy.... GPS stability is certainly a problem.

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First I've heard of it.  A Google turns up a web site that clicks through to a different address.  Can't find a straight answer about how it works.  So, how does it work?

 

https://www.google.com/search?source=hp&ei=wOh5XPCiO4bV-gSH1J6ABA&q=virtual+dyno&btnK=Google+Search&oq=virtual+dyno&gs_l=psy-ab.3..0l10.1519.4254..4643...0.0..0.57.545.12......0....1..gws-wiz.....0..0i131j0i10.yDoexiGlHOM

 

 

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A guy wrote some software and, apparently, many people are downloading it.  But, not understanding how it works.  Could be ransomware.  Weird!

 

https://barnhill.bitbucket.io/

 

http://www.bradbarnhill.com/

 

This is the explanation for "What is Virtual Dyno?".  No explanation.

 

image.png.9efe8d71f108b50a9ba2d3af3a7fe599.png

 

 

 

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A bit of looking around and you'll see that it's definitely the most popular software Dyno out there, buy I also admit that's far from a testimony of safety or validity. What does speak to it's validity is the number of tuners who own dynos that admit to using it and finding it useful.

 

The basic premise is no different than any Dyno. Only, a chassis Dyno has a known load on the dynometer side, while virtual Dyno needs you to give it accurate data for the opposite end, the vehicle side. The only logs it needs is TPS(tells it where the WOT run is to log off), MAP/Boost, and RPM. By giving it gear and tire size it knows your MPH and by giving it aero data it can calculate the wind resistance curve. With this data in can you simply plot the power it takes for acelleration at the logged rate, and you have power.

 

This isn't much different than the phone app dynos, except those rely on good GPS data, which honestly is never fast enough. A 10hz GPS is required, though by 2025 that'll be a thing in most phones I think with the new GPS system rolling out. So phone apps might actually end up being more accurate soon anyway.

 

I've had friends with a Dyno that only bought a Dyno to have a fancy paper for certain customers. Thier high end race customers who were competitive didn't care. Results are results. And how did they Dyno? Excel. They used their own custom estimator they built that would generate curves from logs, same as virtual Dyno. And guess what? When they got thier fancy AWD Dyno in the shop, the results were almost identical. They still preferred road dynoing thohgi. Know why? Becuase the results were more realistic to track conditions because it more accurately took into account aero effects on intake, cooling, and intercooling.

 

Just some food for thought. :-)

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Posted (edited)

Ahh, to correct myself, the three log pieces virtual Dyno needs is TPS, TIME (not map) and RPM. Everything else is just bonus (like MAP and AFR if you have it).

 

A dynometer only requires the same info. Only the TPS is normally an operator triggering the start of the run manually. The dynometer records its own RPM and time, and only needs vehicle RPM input for axis translation.

Edited by Gollum

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You should have noted all of that in your first post, and you should have gotten correct weight, I think.  Especially the weight, since the software depends on it.  You showed 200 HP and a curve with a description that sounded like a mechanical dyno.

 

It all makes sense, but just like differentiating between the dyno machines, you should do the same with a software "dyno".  The basic premise is not really like a mechanical dyno, it depends on many more variables.  Each variable can introduce error.  Even something simple like the wrong speedo gear, I assume.  The software must use speed to calculate acceleration.  Have you had your speedo calibrated?

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Posted (edited)
49 minutes ago, NewZed said:

You should have noted all of that in your first post, and you should have gotten correct weight, I think.  Especially the weight, since the software depends on it.  You showed 200 HP and a curve with a description that sounded like a mechanical dyno.

 

It all makes sense, but just like differentiating between the dyno machines, you should do the same with a software "dyno".  The basic premise is not really like a mechanical dyno, it depends on many more variables.  Each variable can introduce error.  Even something simple like the wrong speedo gear, I assume.  The software must use speed to calculate acceleration.  Have you had your speedo calibrated?

 

All the data was there in my first post, though looking at it again I see I could have been more clear. The graph itself states "virtual dyno" right on the top, and I published ALL my data points to show with others what I used.

 

The speedo data isn't used at all by the HP calculation. It's RPM over time. If you know the rate of change, and you know the load, that's all you need. In theory, you could do the same over MPH, but that's now how Virtual Dyno works, that's how GPS based phone app dynos work, and hence their phone-gps-accuracy-dependency that I feel I've just about killed the topic on here. And by the way, I have no speedo in use. Purely using GPS speedo in my car for MPH reference for myself.

 

IMO, the data I posted could have just as easily come from a mechanical dyno, and people would want just as much of an explanation of numbers. In fact, we've done that here more than once... 🙄

 

I'd expect other veterans here to know from my history that I strive for meaningful, accurate data. And I shared what I have, and what I knew, and have been honest and open about caveats. I've in no way intended to mislead, and feel I've shown that in every post thus far. And at the end of the day let's be honest.... 186whp@5184 is actually damn close to MOST stock L28ET dynos we see.... If I'd had to guess a number ahead of time, I'd have thought it'd be 170-175, about where most L28ET's come in... I mean shoot, drax made 211whp on stock wastegate pressure...

 

Edit:

Re weight:

I agree, meaningful weight data is important to virtual dyno. But a 200lb reduction that would put me WAY under where I think I am would net me a whopping 10hp loss in the calc. I stated in my first post I plan to weigh my car soon, and would update the data once I had more concrete numbers. For now, I assumed 2400 lbs (car last weighed in at 2540lbs and I've removed a lot since) and my own weight at 230 (which might be more like 235-240 once I take into account all my clothing, jacket, hat, pocket knife, phone, steel toe boots, etc). But Even if we look at how much potentially difference there COULD be... it's less of a HP swing than running dynos back to back on a heat soaked engine.

Edited by Gollum

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Posted (edited)
1 hour ago, Gollum said:

 

All the data was there in my first post, though looking at it again I see I could have been more clear. The graph itself states "virtual dyno" right on the top,

 

It's RPM over time. If you know the rate of change, and you know the load, that's all you need.

 

Define load.  Load is inertia.  Inertia is rate of change of speed.  Edit - indirectly.  

 

Again, no offense, always nice to try out new stuff.  But just because somebody wrote a nice software package doesn't mean it's right.  Today's world is full of apps and software and devices and promises that we're all just trusting blindly.

 

The fact that people say it tends to match direct measurements is nice.  Just need some verification.

 

And"it's all there in my first post" is a stretch.  See image.  It's only true if you already know about "Virtual Dyno".

 

image.thumb.png.fc3b6c3dc7bd9ebd9036d354b3704aa5.png

 

Edited by NewZed

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 Hey guys.

That's a hot topic....   Interesting. But i'll have to suggest ending the conversation for now to try to stay on topic.   

Although i have to say: On paper, such a piece of software, fed the right info, should be perfectly right.

Unfortunately, while you might (or not) have fed it the right info, the programer might (or not) have made some mistakes...

Gollum, what would be interesting is for you to follow up your post once you finalise your tune, and post again. OR, even cooler, if you eventually get your car on a physical dyno, make certain you share; it might totally change people's view and give us tools to dyno ourselves ( i.e. software dynos).

In the meantime, it's important that people who share software dyno results spell it out... Gollum was right, the image did say it was from a virtual dyno, but i myself and too dumb to read everything and totally missed it (that does explain all the info about car weight and athmospheric pressire, which i found curious).

 

Thanks, and keep those dyno sheets coming!

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Thanks.  Sorry to be so blunt.  It actually looks like something almost brilliant, after thinking about it, especially considering that it looks like one guy put most of it together.  All of the data is there to do a decent calculation, with the AFR determining how much fuel was burned and the rate of RPM increase, along with other variables, being used to determine acceleration.  Ideally, of course, you'd be on the Bonneville salt flats with zero wind.  But, a flat road on a calm day is pretty close.

 

Thanks for posting.  I learned something new.

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Posted (edited)
On 3/2/2019 at 12:18 AM, NewZed said:

 

Define load.  Load is inertia.  Inertia is rate of change of speed.  Edit - indirectly.  

 

Again, no offense, always nice to try out new stuff.  But just because somebody wrote a nice software package doesn't mean it's right.  Today's world is full of apps and software and devices and promises that we're all just trusting blindly.

 

The fact that people say it tends to match direct measurements is nice.  Just need some verification.

 

And"it's all there in my first post" is a stretch.  See image.  It's only true if you already know about "Virtual Dyno".

 

image.thumb.png.fc3b6c3dc7bd9ebd9036d354b3704aa5.png

 

 

Not to be pedantic, but as a former physics nerd, I have to push back a little bit on this point.

 

Inertia is the property of objects that are at rest to stay at rest or objects in motion to stay in motion. In essence, things don't change velocity unless they're accelerated by some force (this includes objects with zero velocity - "at rest"). Inertia is absolutely not the rate of change of speed. The definition of acceleration is literally exactly that - the rate of change of speed (or more precisely, velocity).

 

In essence, inertia is a property of mass (or in your post's words, "load"). The more mass something has, the more force it will take to accelerate it a given amount. You could think of inertia as the relationship that is the underpinning of the F = MA (force = mass x acceleration) equation. So inertia impacts acceleration very directly, but it isn't acceleration, indirectly or otherwise.

 

It's worth pointing out that the type of math done in the virtual dyno is not really much different than that done on a regular dyno. The only difference being the chasis dyno calculates force by measuring the rotational acceleration of a cylinder of known rotational inertia (the dyno roller). The virtual dyno software is just measuring the linear acceleration of an object with known linear inertia (your car). The error in level ground, true wind resistance and possibly measurement equipment definitely introduces some inaccuracy, but in principal, the analytical method is not any more difficult or more of an extrapolation than a roller dyno. Granting the caveat of slightly less accuracy and R&D than a roller dyno, an in car accelerometer can give pretty precise, repeatable results (I know of two cars -but only two to be fair- that have been street tuned this way, and once on the dyno needed minimal adjustment and produced similar power figures on dyno). I also have seen someone take the rpm/time graph from his data logs, convert it to linear velocity, take the derivative and then calculate his power graph that way. He also got pretty good results.

 

Cheers 

Edited by Ian Summers

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Posted (edited)

Thanks for that correction.  After I posted it I realized it wasn't 100% correct in a universal sense.  Only in a relative sense, objects in motion and all that.  I almost edited it but decided to leave it, and went with "indirectly" instead.  You described in more detail what I meant by "the car is the dyno".  More relativity.  

 

Getting the variables right is the key to good results I think.  On a static "dyno" the variables should all have been calibrated and measured.  On the "virtual" dyno, the car dyno, it's up to the user to get them right.  Small things like tire radius, weight, wind, road slope all play in to it, as you pointed out.  For the "post your dyno results" these things might be more important.  This thread is half brag, half share.

 

Still a neat idea.  Surprising that it hasn't been "app'ed" sooner.

Edited by NewZed

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Posted (edited)

I've been lurking this thread for a few years and I finally have a dyno sheet to share!

 

1- car: 1973 240Z

2- State of the engine: L28ET, P90A head converted to solid lifter, 8:1 +1mm JE forged pistons, Schneider/MSA Stage III turbo cam

3- 258WHP @ 5760RPM, 16PSI

4- 262WFTLBS @ 4940RPM, 16PSI

5- short list of relevant mods if applicable: LoneWolf intake manifold, 240SX throttle body, .63/.63a/r 60 trim T3/TO4E w/ stage III turbine wheel, MS2 3.57 running MSNSE, RC Engineering 550CC injectors, Bosch 044 fuel pump, Aeromotive FPR, MSD StreetFire Ignition, Factory '83 280ZXT dizzy, crappy 2.25" downpipe to 3" exhaust, crappy same-sided intercooler getting doused in watermeth

6- anything else you feel might HELP OR HINDER your hp figures: The downpipe is way too small - pretty sure this robbing 30-40hp, needs a much larger intercooler, needs a heavier wastegate spring for more boost. Potentially could use a cooling mod on the head to run more timing. I will do some of these things over the winter and re-dyno next spring. edit: revisiting some of the data logs from these pulls, the dips in power at 4k and 5k are due to the tune going a bit rich in those spots. Those were also noticeable while driving. Obviously haven't been able to re-dyno yet and won't for a while, but I've fixed these on the butt dyno already.

 

dyno.thumb.jpg.f3bc374889929f1100c127541c1180d1.jpg

 

 

 

Edited by Zcardude

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No experience with turbo builds , but from lots of reading here it seems that the very first things the guys do is the down pipe increase. You have invested a lot of money in forged pistons and other goodies ,  but you are choking all your investments with a tiny exhaust. 

Timing might also be a victim of your small exhaust. Don’t want to build heat by bottle necking flow. What was your timing at?What was your AFR’s?

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