[CJ421]

Huh, your dynos seem kinda low ... maybe it was just the dyno. I had 3 runs on Helix's Mustang MD-250, stock w/ just the PE I was 280HP/322TQ.
Curves look good though.

[ian2002525]

the 5" dp gains too low...only 5 whp and 13 tq.
and on the second dyno jb map1, you lose 22 tq. compares to stock. its weird man.

[turugara]

I know that the exact reason behind a lower tq with the jb tune vs stock can't be pinpointed with a few dyno graphs and that more data is needed. However, just out of pure speculation, what would be a few theory's as to why the tune has lower torque than stock?

[Mike@N54Tuning.com]

Originally Posted by turugara

I know that the exact reason behind a lower tq with the jb tune vs stock can't be pinpointed with a few dyno graphs and that more data is needed. However, just out of pure speculation, what would be a few theory's as to why the tune has lower torque than stock?

All your runs stock and modified have a torque spike during tip in so the absolute numbers are not going to be very relevant. You'll have to look at average numbers.

Also, on the map 1 run you wrote 270tq but the spike goes up to around 320tq or so.

Mike

[turugara]

Originally Posted by Mike@N54Tuning.com

Also, on the map 1 run you wrote 270tq but the spike goes up to around 320tq or so.

Mike

You are correct. I put in both of the HP numbers as oppose to HP/TQ. I will change that.

[turugara]

Originally Posted by Mike@N54Tuning.com

All your runs stock and modified have a torque spike during tip in so the absolute numbers are not going to be very relevant. You'll have to look at average numbers.

Also, on the map 1 run you wrote 270tq but the spike goes up to around 320tq or so.

Mike

As the JB tune is updated and evolves for the n55, will we see a smoother torque curve? What should we expect with software updates on the JB unit?

[Mike@N54Tuning.com]

Originally Posted by turugara

As the JB tune is updated and evolves for the n55, will we see a smoother torque curve? What should we expect with software updates on the JB unit?

I don't know much about your car, the runs, your mods, dme version, etc, so I can't offer you any meaningful advice. You could email logs in to BMS for suggestions on the tuning end. I have some dynos from the Stage1 and BMS produced similar results with the Stage2. I know the N55 has problems with PID overshoot on the dyno stock and modified. On a Mustang dyno that problem is probably a lot worse.



Mike

[turugara]

Thanks mike

Originally Posted by Mike@N54Tuning.com

I don't know much about your car, the runs, your mods, dme version, etc, so I can't offer you any meaningful advice. You could email logs in to BMS for suggestions on the tuning end. I have some dynos from the Stage1 and BMS produced similar results with the Stage2. I know the N55 has problems with PID overshoot on the dyno stock and modified. On a Mustang dyno that problem is probably a lot worse.



Mike

[335 oClock]

... 3whp gain with the dp?

I think all of your dynos are incorrect

[sander]

I felt it pertinent to add a few notes regarding dyno charts, and dyno's in general.

Being a Mustang Dyno center, (at cp-e) I'm often faced with the "your dyno must be broken" comment, at least once a week. Part of the thing to remember about Mustang Dyno's is that they operate in a completely different fashion than Dynojet Dyno's do.

Note: I am not going to condone any type of dyno X is better than dyno Z talk.

Dynojet's generally use a few simple physics calculations to derive HP,

Force = Mass * Accel
Work = Force * Distance
Power = Work * Time

So, basically dynojet HP is calculated based on a number of factors, rpm, wheel speed, and time (among a few other standards and atmospheric inputs). They use very sensitive optical pickups on the rollers to do this.

Mustang's actually measure torque, in real time. There is the equivalent of a torque wrench on the end of the rollers that is used to measure real time torque. Why is this useful? This is indescribably awesome when tuning cars, due to the fact you can do steady state loading at a specific RPM / load (which the dyno will prevent you going past) and adjust timing or fueling to see if the torque increases or decreases. MD's are a great tool, beyond it's myriad of other cool features (that I won't waste your time talking about, )

Which brings me to my next point, dyno's shouldn't ideally be used for absolute measurements. Example, "Well, the 1M made 366 WTQ on the insideline blog review so your dyno is broken because it only made 320 WTQ on your dyno"

Dynamometers are used as tools to identify changes in the HP and TQ curves at that dyno session, that day. There are a number of different factors that play in to the amount of power an engine can make, measurement strategy that dyno X uses, atmospheric conditions / elevation, humidity, temperature, etc...

All dyno's (that I've used, MD, dynojet, mainline, dyno dynamics, dynapak) have atmospheric calculations, based on humidity, temperature, and atmospheric pressure, but again, they are only really to keep standardization and consistency on that dyno, on that day.

As an example, the insideline 1M test yielded 366 WTQ, and 331 WHP.
http://blogs.insideline.com/straight...s-m-coupe.html

Our 1M, made 322 WTQ and 295 WHP. These were both dead stock cars, FYI.



If you wanted to come up with an imaginary correction factor between our two dynos (which is pointless, but someone will likely ask anyway), you could divide the TQ and HP from both charts and find a percentage difference. It works out to be around 10-15 % less on the MD.

Also a note on scaling, The dynojet graph pictured above (a few posts up) is scaled from 0-500 hp / tq. It looks nice and smooth. While the graphs from Steve's car look somewhat lumpy and odd. While I do suspect there was some wandering boost pressure there (as the tq curve does wavier a bit), they are much smoother looking if you rescale the chart from 0-400 hp / tq.



And then...on top of all of the dyno comparisons, you've got the variability of piggyback controllers, conditioning signals to the DME in the first place. Most of the ones on the market do a pretty great job, but the real solution in my mind for the N54 / N55 people is a proper standalone computer. (sander...patiently awaits...)

Apologies if that was long winded, or slightly off topic at times. Hopefully someone got something out of it.

-Sander (guy with hat in first picture)

[turugara]

Oh good. So my car isn't broken. =]

[Bagelfast]

WOW! Nice.
CP-E offers amazing quality and amazing products.. There R&D is the best in the industry.

[PlutoniumTans]

wtf is the point of this 5 inch dp ?

[PlutoniumTans]

This downpipe is FAIL, 3.5 inch is more than enough

[D335NUTZ]

Originally Posted by Sloppy

Wonder if it hits anything down there??? My Vishnu dp was a tight fit... I dun wanna know how tight this guy is!

That's what she said.

[theART]

Never mind low stock Dyno HP, but 5HP from downpipe "upgrade"?!

It seems all the potential power gains got lost in 5" of tubing.

Art