Dyno from my NB2 engine... anything seems fishy ?
06-25-2015, 10:29 AM
#1
Dyno from my NB2 engine... anything seems fishy ?
I brought my USDM NB2 engine (40k miles) for some dyno tunning.
Setup :
180psi per cylinder (COLD) will redo it tonite HOT
leak below 5%
VICS intake manifold (6400 switch dyno tuned), stock TB
U bend on cold side near shock tower (Aluminum pipe)
MS3 basic
Racing beat header
2.5'' mid pipe cat less to magnaflow muffler
Tune for 91 and race with 94 (safety)
Here's the result :
This is ambient +20C (race config) at ambient we we're at 140-126..
There's a big dip and power doesn't seem flat like I thought it would...
Will post my tables when I'll get back home.
Setup :
180psi per cylinder (COLD) will redo it tonite HOT
leak below 5%
VICS intake manifold (6400 switch dyno tuned), stock TB
U bend on cold side near shock tower (Aluminum pipe)
MS3 basic
Racing beat header
2.5'' mid pipe cat less to magnaflow muffler
Tune for 91 and race with 94 (safety)
Here's the result :
This is ambient +20C (race config) at ambient we we're at 140-126..
There's a big dip and power doesn't seem flat like I thought it would...
Will post my tables when I'll get back home.
Last edited by joyrider; 06-25-2015 at 11:24 AM.
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06-25-2015, 03:31 PM
#2
How long is the intake pipe, measured from TB plate to filter cavity?
I'm guessing a bit more VVT table tuning would reduce the dip. But the dip is normal, maybe less severe with some more careful tuning. Otherwise, dyno looks about right.
I'm guessing a bit more VVT table tuning would reduce the dip. But the dip is normal, maybe less severe with some more careful tuning. Otherwise, dyno looks about right.
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Last edited by emilio700; 06-25-2015 at 04:59 PM.
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06-25-2015, 09:01 PM
#6
I'd move set point to coincide with dip, around 3500rpm, reduce angle there. Increase angle just after 3500 and up to about 5500 then start tapering back down there. Dip can be reduced by cutting back VVT angle and adding timing.
No need for VVT set points at 1700, 2500, 2800 and 3000. Get rid of one to add another somewhere else it will help.
AR target is odd. 13.0 on 91 is aggressive. Good power but I'd run 12.8 closer to VE peak, 5200-6400.
No reason to run an fatter than 14.7 from 65kpa on down.
All your tables stop at 100kpa. Not a big deal but a healthy NB2 with I/H/E will touch 105 near the VE peak. I'd revise that set point.
RPm columns stop at 7k but you plot shows 7360. I'd extend tables out just past rev limiter.
Did you use det cans or just listen for knock? You should be able to run 2-3° more timing above 5500. With USDM 10.0:1, you should be able to reach MBT no problem. That means lots of timing until you hear popcorn then back off 3°.
22" pipe is close enough. I wouldn't worry about that.
No need for VVT set points at 1700, 2500, 2800 and 3000. Get rid of one to add another somewhere else it will help.
AR target is odd. 13.0 on 91 is aggressive. Good power but I'd run 12.8 closer to VE peak, 5200-6400.
No reason to run an fatter than 14.7 from 65kpa on down.
All your tables stop at 100kpa. Not a big deal but a healthy NB2 with I/H/E will touch 105 near the VE peak. I'd revise that set point.
RPm columns stop at 7k but you plot shows 7360. I'd extend tables out just past rev limiter.
Did you use det cans or just listen for knock? You should be able to run 2-3° more timing above 5500. With USDM 10.0:1, you should be able to reach MBT no problem. That means lots of timing until you hear popcorn then back off 3°.
22" pipe is close enough. I wouldn't worry about that.
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06-25-2015, 09:31 PM
#7
I'd move set point to coincide with dip, around 3500rpm, reduce angle there. Increase angle just after 3500 and up to about 5500 then start tapering back down there. Dip can be reduced by cutting back VVT angle and adding timing.
No need for VVT set points at 1700, 2500, 2800 and 3000. Get rid of one to add another somewhere else it will help.
AR target is odd. 13.0 on 91 is aggressive. Good power but I'd run 12.8 closer to VE peak, 5200-6400.
No reason to run an fatter than 14.7 from 65kpa on down.
All your tables stop at 100kpa. Not a big deal but a healthy NB2 with I/H/E will touch 105 near the VE peak. I'd revise that set point.
RPm columns stop at 7k but you plot shows 7360. I'd extend tables out just past rev limiter.
Did you use det cans or just listen for knock? You should be able to run 2-3° more timing above 5500. With USDM 10.0:1, you should be able to reach MBT no problem. That means lots of timing until you hear popcorn then back off 3°.
22" pipe is close enough. I wouldn't worry about that.
No need for VVT set points at 1700, 2500, 2800 and 3000. Get rid of one to add another somewhere else it will help.
AR target is odd. 13.0 on 91 is aggressive. Good power but I'd run 12.8 closer to VE peak, 5200-6400.
No reason to run an fatter than 14.7 from 65kpa on down.
All your tables stop at 100kpa. Not a big deal but a healthy NB2 with I/H/E will touch 105 near the VE peak. I'd revise that set point.
RPm columns stop at 7k but you plot shows 7360. I'd extend tables out just past rev limiter.
Did you use det cans or just listen for knock? You should be able to run 2-3° more timing above 5500. With USDM 10.0:1, you should be able to reach MBT no problem. That means lots of timing until you hear popcorn then back off 3°.
22" pipe is close enough. I wouldn't worry about that.
AFR set at 13, dyno with 91 but race with 94 for safety margin.
We just listened for knock, will look into det can. MS3 is just missing an earphone plug...
Will send those info to my tuner and take an appointment.
Thanks
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06-26-2015, 07:09 AM
#9
Here's a reply from my tuner with some explanations (I told him about the dip wich is normal on those engines) :
I chose those vvt setpoints because they were where the sweeps at fixed angle crossed over, once interpolation had been taken into account. There was no need for other setpoints anywhere else.
Emilio says "reduce", not eliminate, the dip. Does this mean the existence of the dip is normal?
I'll stick with the 13:1 AFR too. We tried up to half a point richer and leaner. 13:1 was happiest.
Regarding timing, there was no more power to be had. I tested for it. No det cans used.
I'll check the msq and logs on Monday, but I don't think we went over 100kpa. I will add a row if needed.
JF's car is a track toy. Running a bit richer on lighter load can slightly improve throttle response.
Regarding fuel, our good 91 (Shell) has no ethanol. We also have 94 octane pump gas available, with some ethanol in it.
Given what you now know about the tune and testing, do you still have the same recommendations?
Thanks!
Emilio says "reduce", not eliminate, the dip. Does this mean the existence of the dip is normal?
I'll stick with the 13:1 AFR too. We tried up to half a point richer and leaner. 13:1 was happiest.
Regarding timing, there was no more power to be had. I tested for it. No det cans used.
I'll check the msq and logs on Monday, but I don't think we went over 100kpa. I will add a row if needed.
JF's car is a track toy. Running a bit richer on lighter load can slightly improve throttle response.
Regarding fuel, our good 91 (Shell) has no ethanol. We also have 94 octane pump gas available, with some ethanol in it.
Given what you now know about the tune and testing, do you still have the same recommendations?
Thanks!
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