Hesitation in boost and high rpm

[AJP turbo]

What is your desired tip on the 89 octane tune? I only saw your tune that had a desired tip of 186 kpa...is the 89 octane tune less?

Lower load will be lower mass airflow which will require less fuel mass delivered which will help to not consume the fuel in the rail

If the 89 octane tune is better and the desired tip is the same then that is either because the temps are warmer or the 91 octane tune file is possibly corrupted my guess...uncommon though

[polskifacet]

Just uploaded 9 89tune and 10 93tune  these are with 3 gallons of 100 octane added to 20% fuel left on the gauge. Seems like improvement, will take closer look when I get home.

[AJP turbo]

Octane has nothing to do with a pressure problem...all you're going to do with high octane is make the ecu scale spark via oar.

[polskifacet]

Without a benchmark volume, I cant do anything else. Hopefully LMS could do it on their shop car. Any additional data is valid imo, could lead to clues.

[BoostedSho2010]

Maybe not enough timing ? I have got pretty good at reading my data logs my car like a lot of timing. I have 2 different tunes from different tuners I compare. Big difference


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[BoostedSho2010]

Maybe not enough timing ? I have got pretty good at reading my data logs my car like a lot of timing. I have 2 different tunes from different tuners I compare. Big difference


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that's iat 2 temps blue one



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[BoostedSho2010]

good vs not good to much ethanol knock stopped pressure dropped


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[AJP turbo]

Timing has nothing to do with fuel pressure

[derfdog15]

good vs not good to much ethanol knock stopped pressure dropped


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IMO, fuel pressure issues with "too much ethanol" is due to having too much ethanol, you need more volume of ethanol than of normal gas, so if the mix was too heavy on ethanol fuel needed would be higher, thus taxing pumps more. That is my .02 on that.

[BoostedSho2010]

good vs not good to much ethanol knock stopped pressure dropped


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IMO, fuel pressure issues with "too much ethanol" is due to having too much ethanol, you need more volume of ethanol than of normal gas, so if the mix was too heavy on ethanol fuel needed would be higher, thus taxing pumps more. That is my .02 on that.

Yea I was trying to stop knock and it did but was not safe


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[BoostedSho2010]

Timing has nothing to do with fuel pressure

I know but it has something to do with hesitation. My car hesitates a lot when it does not have enough timing. Compared to when it's dialed in.


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[AJP turbo]

Timing has nothing to do with fuel pressure

I know but it has something to do with hesitation. My car hesitates a lot when it does not have enough timing. Compared to when it's dialed in.


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Your car hesitates because of something else...Timing follows load...The ECU is always trying to run the max amount of spark allowed.....It wants to tickle the knock sensor.

Basically the knock logic is running the max allowed spark at all times.

[polskifacet]

Is there a way to see what voltage the HPFP solenoid is getting with the SCT? I wonder if the solenoid is getting incorrect voltage once it starts going higher than stock fuel demand.

[polskifacet]

Not sure if it helps or not, but here is a log of my XSport in cold(er) temps. I'm not certain, but I assume the fuel system is the same as the SHO?

I also had the AJP boost regulator installed, so it would have helped minimize pressure drops during shifts.

Ambient: 8.6 F
IAT2: mid 50s at start of runs
Target Boost: 14.5 PSI

Note, since this log was taken, I've changed the regulator boost reference and moved down to 15.95 PSI springs, which helps with the pressure drops. We've not had any bitter cold since making these changes, but if it gets back down close to 0, I will log again for comparison.

My log looks very similar to MiWiAu even though he is running more boost(1.5 psi more), the curve, frp recovery and variation is oddly similar.

[AJP turbo]

Not sure if it helps or not, but here is a log of my XSport in cold(er) temps. I'm not certain, but I assume the fuel system is the same as the SHO?

I also had the AJP boost regulator installed, so it would have helped minimize pressure drops during shifts.

Ambient: 8.6 F
IAT2: mid 50s at start of runs
Target Boost: 14.5 PSI

Note, since this log was taken, I've changed the regulator boost reference and moved down to 15.95 PSI springs, which helps with the pressure drops. We've not had any bitter cold since making these changes, but if it gets back down close to 0, I will log again for comparison.

My log looks very similar to MiWiAu even though he is running more boost(1.5 psi more), the curve, frp recovery and variation is oddly similar.

I'm not sure there were that similar...I'd have to see exactly which 2 you are looking at....But his boost was higher AND the temps were super frigid and his recovery was much better if I remember...Your log show a clear lack of fueling for the boost level