N52 intake shootout

[varg]

Usually you can get an optical tachometer close enough to the crank pulley to read with the appropriate marking placed on it, and use that to verify the accuracy of the car's tach. I've done this before myself, and it seems prudent for dyno operators to have one on hand in the unfortunate circumstances where someone doesn't have the ability to plug in and display actual engine RPM with tuning software or even OBD

[hoveringuy]

What are they using? dynocum?

It’s not hard to pick up signal to the coil.

What do they use for wideband or do you log with on the wideband?

My upstream sensor are Wideband, obviously, but I'm not currently logging, although I know there's an application that will do that.

When they tune the fuel they run it steady-state at a bunch of different speeds/loads and log the ECU correction. Correct the fuel table and repeat until ECU corrections are close to zero. I think there will be several rounds of tuning, starting with getting the fuel right and then timing of both ignition and VANOS.

My understanding of the full throttle is that the ECU makes corrections in real-time to match the A/F table which is mostly 13.0 so I don't know how that's tuned.

I'll get dyno details next time I'm there.

I think the 10 percent discrepancy is more of a "move the graph right' because I'm probably doing at 3000rpm what they think I'm doing at 2700, or something like that.

[moatilliatta]

What are they using? dynocum?

It’s not hard to pick up signal to the coil.

What do they use for wideband or do you log with on the wideband?

[hoveringuy]

So… 22rpd 30hp high?

It seems like theyre off more on the low end. If Luke made 248 to my 268 in the same configuration thats 20, but I figured 10%.

Ill know better when I do another baseline in a few weeks at 22RPD when I fix fueling.

I think it probably also has a lot to do with improper RPM at 22RPD, the Dynojet has a pickup and RPM is exacct, 22 just kinda matches the tach with the rollers for something that's kinda close.

[moatilliatta]

So… 22rpd 30hp high?

[hoveringuy]

So I replaced both DISA valves and the car pulls much stronger on the top now.

I took it to a Dynojet for a baseline to get an apples to apples with all of the other Dynojet data moatilliatta . 243STD/235SAE isn't bad but it's not great either. Keep in mind, this is basically untuned and hasn't been optimized. A/F is fat at 12.

[hoveringuy]

it doesn't matter if provided they did it same way for both runs for a comparison.

i just don't trust the operator as i have seen them stuff it up and use a different scale factor for baseline vs the after run when nothing changed which makes comparisons of graphs with rpm as Y axis useless

LOL, either do I! I had him go to the old run and copy the scaling factor, otherwise would have been garbage comparison.

[digger]

Yeah, It noticed that as well, Dynojet always has a pickup to get actual motor RPM, this one uses a scaling factor to convert roller speed to tach rpm, so the best they do is hold it at 2000 and make sure the tach matches the display.

This dyno is valid for the moment as an "apples to apples" comparison of the same motor on the same dyno with different configurations, but when I get it done Ill need to throw it on the Dynojet to get numbers that can be compared to other Dynojet numbers.

it doesn't matter if provided they did it same way for both runs for a comparison.

i always ask for a road speed graph as well so i can work out the rpm to speed conversion as the tacho might be a bit off depending on the rpm and i get a better rpm number from the ECU.
i just don't trust the operator as i have seen them stuff it up and use a different scale factor for baseline vs the after run when nothing changed which makes comparisons of graphs with rpm as Y axis useless

[hoveringuy]

The other thing to is check how they are getting the rpm signal and that it is correct as that can skew torque

Yeah, It noticed that as well, Dynojet always has a pickup to get actual motor RPM, this one uses a scaling factor to convert roller speed to tach rpm, so the best they do is hold it at 2000 and make sure the tach matches the display.

This dyno is valid for the moment as an "apples to apples" comparison of the same motor on the same dyno with different configurations, but when I get it done Ill need to throw it on the Dynojet to get numbers that can be compared to other Dynojet numbers.

[digger]

Not Dynojet, it's a magneto-resistance one that's supposedly calibrated to match Dynojet (there's a Dynojet up the road and they say cars are the same on the two)
Nice thing about this one is it's perfect for holding part-throttle load for data logging and fuel corrections.

We werent holding it that long because it was pointless.

when you get things sorted just put it on an actual dynojet for some numbers that mean something in an absolute sense when said and done, operators are always talking BS. when they say calibrated to a dyno jet they just mean they fudging numbers which makes them kind of useless as the differences between dynos change depending on which vehicle is used as the "calibration" and you cant calibrate the curve just to a peak so very easy to create a random number generator. The other thing to is check how they are getting the rpm signal and that it is correct as that can skew torque

[DEV0 E30]

Thanks again for sharing and improving this swap for everyone else.

[LukeJ]

Dang it! haha. This is some good info here.

I guess I have some more work to do....

Thanks!

[hoveringuy]

What type of dyno? Are you Reving out to 7800?

Not Dynojet, it's a magneto-resistance one that's supposedly calibrated to match Dynojet (there's a Dynojet up the road and they say cars are the same on the two)
Nice thing about this one is it's perfect for holding part-throttle load for data logging and fuel corrections.

We werent holding it that long because it was pointless.

[moatilliatta]

What type of dyno? Are you Reving out to 7800?

[hoveringuy]

Baseline dyno!

Good news and bad news...

The good news is that I've picked up 17 torques at 3100. Interestingly, both graphs have peak torque at exactly 3168. What are the odds? There's a 10-15hp boost all the way to almost 5000.

The not as good news is that the motor kinda dies by 6000, but nando quickly noticed that the torque curve doesn't have the characteristic torque peaks that other N52's have. INPA shows that the DISA valves are opening and closing, and I can hear them "click" but removing them showed that it was bound-up at best and then it was stuck closed, so two new DISA valves are in the mail (they're at risk of disintegrating at this age, anyway)

That's opportunity #1, number 2 is that the A/F until around 4500 was in the 15.5 range, so there's room for a better fuel map which should bump power. The thought of getting 270ft-lbs is just delicious, show me an S54 that makes 270 ft-lbs....

The dyno is something of a dick measuring contest, what's more important is how the car feels to drive and from 6th gear on the freeway to getting groceries it's awesome now, it sure feels like 262 ft-lbs.