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I think the gap on the ring is normal.. this is mine brand new.

Mine car also has a stronger fuel stench as well.. Can't figure out where it's coming from.
 

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Discussion Starter #23
Ah! Thanks for confirming about the gap... and the fuel smell. Hope this isn't normal for BOE systems!
 

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What's interesting is that your AFRs look great. The intake tube around MAF is the BOE part so calibration should still be good. How's the compression? Have you done a leak-down test? Something is majorly amiss.
 

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Gas smell? That's not right. Are you sure all your pistons are firing?
Super easy to check by checking header temperature on each cylinder after a pull. Something is for sure off.

Is this dyno shop able to change anything in the tune or look at it? Or are you just trying to trace down mechanical issues on the Dyno?
 

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The more I think about it, the more mysterious this becomes. With the AFRs looking so good, it must mean that all cylinders are firing. I can think of only two things to cause low numbers:
  • very retarded timing
  • some sort of boost leak/low boost issue
 

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The second dyno graph you posted is fairly close to your comparison. That could just be due to differences in conditions in the days the car was run. I would not be concerned with a 10whp discrepancy. The big concern is when the car spikes lean. That is definitely a fueling issue and the likely culprit is either the injectors, fuel pump, or fuel pressure (not properly regulated or springing a leak). The tune could also be the culprit but since this is an OTS tune I'm guessing you have a problem with your hardware. You never confirmed if the fuel pressure is boost referenced. If the fuel pressure regulator is not increasing pressure to combat boost I would guess that is your problem.

To illustrate the point. The stock fuel pressure at the rail is 43.5psi. if this pressure is boost referenced it will remain at 43.5psi even under boost by increasing the pressure from the pump to 60psi at 16psi of boost which results in 43.5psi at the fuel rail. You would only need 665cc injectors to make 330hp at the wheels with a Max injector duty cycle of 90%. If you don't boost reference the fuel pressure you end up with 27.5psi of fuel pressure at the rail under full boost (16psi). You would need the injectors to be at 100% duty cycle to just barely scrape by with 750cc injectors and that's assuming the math is 100% accurate. You would really need 850cc injectors to maintain proper fueling at 90% duty cycle or 950cc injectors to maintain proper afrs at 80% duty cycle. I generally like to shoot for a Max of 80% duty cycle so the injectors have some headroom if conditions change.
 

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Discussion Starter #29
Thanks Ryan! Tbh I'm unsure if they are boost referenced or not, but I inherited the engine/transmission/fuel system complete from the previous owner, and this was a blueprinted engine setup built by BOE at their factory so I'd be very surprised if the pressue isn't boost referenced. The injectors are 750cc.

I do have a BOE fuel pressure regulator and pressure gauge coming off the surge tank on the fuel line. According to my shop they did look at this value and it appeared constant during the dyno run. I'd like to verify this myself so I'll be installing AFR and fuel pressure gauges soon. The one in there is a little inconvenient, being in the engine bay. If I'm understanding you correctly I should see that number stay at 43.5 at WOT at all rpms.
 

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Discussion Starter #30
The more I think about it, the more mysterious this becomes. With the AFRs looking so good, it must mean that all cylinders are firing. I can think of only two things to cause low numbers:
  • very retarded timing
  • some sort of boost leak/low boost issue
I don't know if it's timing or the cylinders - my shop inspected the cams & timing & confirmed it was correct. Also, I only smell gas when the engine is off, and it's coming from near the surge tank, not the engine. It's at a level where you need to be sniffing around there to smell it, but parked for a day it starts to stink up my small garage.
 

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The BOE fuel pressure regulator is boost referenced. I would check that connection just to be sure the vacuum line is not split or hooked up to an incorrect boost reference source. The fuel pressure should remain constant at all times for the tune to provide the correct amount of fuel.

It sounds like you currently don't have a wideband afr sensor installed. It is also possible the shops unit that they stuck in your tailpipe was malfunctioning so it's good to have your own sensor in the exhaust that you can use to validate their readings. Going lean at full tilt like that is a serious problem so I hope you get it figured out.
 

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Discussion Starter #32
Thanks Ryan! BOE's advice was to check the fuel system as well for faulty connectors or split vac line. I haven't really driven the car at all after the dyno run, and always keeping it under 5k & not going WOT. Definitely do not want to damage the engine. I do agree though, I need more info here.
 

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I do have a BOE fuel pressure regulator and pressure gauge coming off the surge tank on the fuel line. According to my shop they did look at this value and it appeared constant during the dyno run. I'd like to verify this myself so I'll be installing AFR and fuel pressure gauges soon. The one in there is a little inconvenient, being in the engine bay. If I'm understanding you correctly I should see that number stay at 43.5 at WOT at all rpms.
I am not sure where the gauge reads but it is slightly confusing. What you actually care about it the pressure delta at the fuel injector. On a NA car, 43psi all the time is good. On a forced induction car you care about the delta at the fuel injector. Fuel pressure in the rail should increase with boost pressure.

example numbers:
Boost: 0psi
Fuel: 43.5psi (43.5+0)
Fuel pressure delta at injector (43.5 - 0psi boost in plenum): 43.5psi

Boost: 5psi
Fuel: 48.5psi (43.5+5)
Fuel pressure delta at injector (48.5 - 5psi boost in plenum): 43.5psi

Boost: 10psi
Fuel: 53.5psi (43.5+10)
Fuel pressure delta at injector (53.5 - 10psi boost in plenum): 43.5psi

In an extreme example: a Drag Car making 50psi of boost, if he has 45 psi of fuel pressure, then when the injector opens, no fuel will flow at all. The fuel pressure must be at 90+psi at that level of boost to properly flow fuel.
 

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Yeah but the AFR's look great in the dyno plot originally posted. I'd love to see the boost pressures logged as well. Could be a slipping belt (too big of a belt or an oily belt).
 

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Discussion Starter #35 (Edited)
Update: Andrew at BOE feels pretty strongly that the intake is altering the MAF values. He believes it could be the smoking gun. I've ordered a replacement BOE filter, will report back with results (once my gauges come in too)

Kevin - good point about the fuel pressures and deltas, thanks for explaining that to me! I think the gauge sits before the regulator, but I could be wrong. In that case showing a constant value would be incorrect. Will double check.
 
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