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Unknown dip in dyno graph

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Old Apr 23, 2020 | 08:07 AM
  #1  
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Unknown dip in dyno graph

After the break-in period, I decided to get a conservative tune before pushing it with meth or e85. As you can see in the dyno graph there is a dip during wot acceleration under boost. On the road it feels like fuel cut or boost cut, the car momentarily bogs down and takes off again. There is no hiccup if I accelerate slowly with partial throttle.

My tuner said it may be because of too much secondary injectors however he was doing long distance/remote tuning and I see plenty of people here running a similar setup to mine.

Any ideas what can be the reason; is it the tune or the injectors or something else?

Specs:
GTX35R T4 1.06
Dual 44mm wastegates
Mild streetport
2 x FIC 750 primary inj (Bosch EV14)
4 x FIC 2200 secondary inj (Bosch EV14)
Xcessive LIM (4 port)
Dual Aeromotive pumps (2nd pump kicking in on boost)
Haltech Elite 1500


Last edited by ALPSTA; Apr 23, 2020 at 09:01 AM.
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Old Apr 23, 2020 | 01:02 PM
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That looks like where the secondaries come on.
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Old Apr 23, 2020 | 01:22 PM
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I agree about the 2ndary injector transition.

An upgraded ignition system can make it alot easier to get the car running smoothly on a rough tune,

but there is no substitute for a proper tune. Tuner may have to work the injector offset table and or the transition parameters.
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Old Apr 23, 2020 | 01:29 PM
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What are the AFR/Lambda numbers doing when you cross that dip? What about primary & secondary injector duty cycles? Hopefully that data was logged along with all the other key figures (i.e.., MAP, RPMs, coolant/intake air temps, throttle position, etc.) because the HP/torque curves alone can't tell you jack about why there's a dip there.

But I'd agree it's probably a secondary staging issue; recommend taking a close look at how your Haltech is managing the transition.
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Old Apr 24, 2020 | 08:53 AM
  #5  
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I forgot to mention before, I have the Sakebomb ignition system. Attached is the log file. It was saved as an excel sheet for some reason. I also have the tune file but couldn't upload here because of file format.

The tuner tried to smooth out the transition but he was unable to do so. His conclusion was secondary injectors were too big. My buddy thinks we should downsize and change the injectors to ID injectors because Bosch EV14s are CNG injectors. I am ok with changing my setup if necessary.

What would be the tried and true injector setup which would work with both pump fuel and e85 @ 500hp? And any recommendations on reputable tuners who do long distance tuning?
Attached Files
File Type: csv
RX7 - Second tune.csv (928.3 KB, 81 views)
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