[majj35]

UPDATE Jan 18, 2022: Datalog posted (Post #15)

Before you say anything (no bashing plz), tuner is an expert on GTRs in the Middle East. Tuner himself owns 5+ R35s so he knows what he's doing... but yes sometimes errors are made and I'm here to ask for your advice on Boost cuts and timing pulled that I'm facing often during hard pulls.

So since my new built short block, turbos, trans etc (Alpha 9) I've been noticing gauge flashing and timing pulled during hard pulls. Usually -2 to -4, but recently had 2 boost cuts around 6,500rpms, with -5 pulled @ 21 psi (map 0, around 720-740whp) and it's quite embarrassing and annoying. I raised the issue with my tuner and he informed me that: Yes he did adjust up to -5 pulls for knock safety, and also mentioning that with my current power and cold weather, no humidity at the moment, the extra O2 can cause cuts. He said he can fix that issue by retuning, but the car would have less power. One thing to note: over here we run 95 RON pump gas, and it's not the best.

Last night did a pull, with a boost cut and also got Limp Safety 16, which is "KNOCK"

I'm here to ask, is that something common or a tuning issue? is up to -5 timing pulled "without boost cuts" normal and safe for the engine? What are some solutions? Thanks

 

[alexdavis]

.

I don't have an opinion.
But I wonder if you have discounted a consideration of a simple "Work-Around." Some sort of octane booster additive, using your present tune?

 

[majj35]

I don't have an opinion.
But I wonder if you have discounted a consideration of a simple "Work-Around." Some sort of octane booster additive, using your present tune?

Haven't yet. I also have the option to run C16 on Map 2 and 3, but haven't had the chance to do so yet

 

[240Z TwinTurbo]

Post a log

BTW, the fact you came here to ask the question suggests you know the answer. You should never have a tuning strategy that anticipates engine knock and a subsequent ignition retard because what’s the point? Knock doesn’t benefit the engine and continuously pulling timing doesn’t benefit power or your driving experience. It’s ok to be aggressive, but what you’re describing is a tune that is not appropriate for the fuel you’re running. There is not a scenario I can think of where you want to be experiencing what you described.

 

[gtrbillet]

Floor it off the bottom of third gear and let it go to redline. Post that log.

 

[majj35]

Post a log

BTW, the fact you came here to ask the question suggests you know the answer. You should never have a tuning strategy that anticipates engine knock and a subsequent ignition retard because what’s the point? Knock doesn’t benefit the engine and continuously pulling timing doesn’t benefit power or your driving experience. It’s ok to be aggressive, but what you’re describing is a tune that is not appropriate for the fuel you’re running. There is not a scenario I can think of where you want to be experiencing what you described.

I know the answer from my tuners’ pov. Im here bcus i want to see if this happens with other owners. Btw, this has been a common issue with me.. even in the past (back in the US, during FBO) had 2 different tuners and still experienced some timing pulls and a few times of limp 16…

Will post a log soon

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[V37Skyline]

You’re tune is too aggressive. Either dial it back and accept less power, or find a way to improve your octane/fuel quality. I personally would look into water methanol injection. It’ll up your effective octane, clean your valves, and most importantly cool down the cylinders. I think it’s you’re best bet if you don’t want to compromise power.

 

[240Z TwinTurbo]

I know the answer from my tuners’ pov. Im here bcus i want to see if this happens with other owners. Btw, this has been a common issue with me.. even in the past (back in the US, during FBO) had 2 different tuners and still experienced some timing pulls and a few times of limp 16…

Will post a log soon

Your tuner's response that lowering the timing will eliminate the knock, but reduce the power, is 100% correct. However, the fact that he presents this as a negative consequence is concerning. You run the amount of timing that can be handled for the fuel you are using plain and simple. The tuner needs to eliminate the knock completely and then I would recommend you run an octane booster as a safety factor if you're gonna beat on it hard with pump fuel.

 

[L.L.]

Can't expect to keep the fuel and tune constant yet expect the results to change. Either up the octane or fix the timing in the tune so it doesn't need to pull timing dynamically when knock is detected.

It may be an inconvenience but if 55 gallon drums of better fuel or ethanol are available in your country, maybe it's time to go flex tune and learn how to mix your own fuel if the alternatives (compromises) aren't acceptable solutions. 95 RON just isn't going cut it even at the stock level so it wouldn't be realistic to expect it to be any better at your power level.

 

[BlueGTRisBestGTR]

what fuel can you readily get? methanol?

 

[majj35]

Your tuner's response that lowering the timing will eliminate the knock, but reduce the power, is 100% correct. However, the fact that he presents this as a negative consequence is concerning. You run the amount of timing that can be handled for the fuel you are using plain and simple. The tuner needs to eliminate the knock completely and then I would recommend you run an octane booster as a safety factor if you're gonna beat on it hard with pump fuel.

and that’s what I’m here for! Thank you for that I’ll bring it up with the tuner and adjust as well as seeing which octane booster to add.


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[majj35]

Can't expect to keep the fuel and tune constant yet expect the results to change. Either up the octane or fix the timing in the tune so it doesn't need to pull timing dynamically when knock is detected.

It may be an inconvenience but if 55 gallon drums of better fuel or ethanol are available in your country, maybe it's time to go flex tune and learn how to mix your own fuel if the alternatives (compromises) aren't acceptable solutions. 95 RON just isn't going cut it even at the stock level so it wouldn't be realistic to expect it to be any better at your power level.

Unfortunately that’s the max we have , horrible i know. I do have flex fuel. I’ll try adjusting the tune and going for an octane booster.. and other times just use C16 i do have 2 maps for that.


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[BlueGTRisBestGTR]

How does it run on c16?

 

[majj35]

How does it run on c16?

Haven’t triee that yet. Wanted to break in the motor on low pump gas map first. Will try it sometime soon


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[majj35]

Post a log.

Here are 2 logs I just did.

Datalog2: Had a Boost Cut with timing pulled, and Limp Safety 16. (all driving modes were on Normal + manual shifting)

• -2 Timing pulled starts @ 20+psi (row 203)
• -5 timing, with Limp Safety 16 "knock" (row 269)

Datalog3: Shows -3 pulled, on 1st gear without boost yet, then it adjusts back under boost. No limp. (R transmission mode, rest is on Normal, manual shifting)

• -3 timing start (row 2)
• timing back to 0 (row 259)

Pump Gas 95 RON (equivalent to 91 octance), Built 3.8 Short Block, A9+ Turbos, GSC S1 Cams, Twin Walbro 525lph w/fuel lines, Asnu 1100cc, 3" intakes, stock upper pipes, Alpha street fmic, HKS BOV vent to atmosphere, dp/mp/exhaust. Weather: 64f, Engine oil temp: 174F, Coolant: 172F, Trans oil temp: 162F

I'm sharing the logs with you first before hitting up my tuner. I value your opinions more, and would like to see what you think the problem is so I can discuss with my tuner by letting him know what's really wrong, and not have him brush the issue as if I don't know what's happening.

just realized, forgot to include Throttle Pos% & Theo PW, are you still able to identify the issue? trying to avoid re-datalogging and throwing the car on limp again
Thanks in dynamic advance haha

^after my 1st log (datalog2) w/ cut

 

[colo_evo]

I'm sharing the logs with you first before hitting up my tuner. I value your opinions more, and would like to see what you think the problem is so I can discuss with my tuner by letting him know what's really wrong, and not have him brush the issue as if I don't know what's happening.

Get a new tuner. Your relationship is already destroyed.

 

[240Z TwinTurbo]

You're tune is running too much ignition timing for pump fuel, which is even worse because it's 91oct pump fuel. No need to even comment on other aspects of the tune. If you want to damage your engine I recommend staying with the current tuner.

 

[V37Skyline]

Here are 2 logs I just did.

Datalog2: Had a Boost Cut with timing pulled, and Limp Safety 16. (all driving modes were on Normal + manual shifting)

• -2 Timing pulled starts @ 20+psi (row 203)
• -5 timing, with Limp Safety 16 "knock" (row 269)

Datalog3: Shows -3 pulled, on 1st gear without boost yet, then it adjusts back under boost. No limp. (R transmission mode, rest is on Normal, manual shifting)

• -3 timing start (row 2)
• timing back to 0 (row 259)

Pump Gas 95 RON (equivalent to 91 octance), Built 3.8 Short Block, A9+ Turbos, GSC S1 Cams, Twin Walbro 525lph w/fuel lines, Asnu 1100cc, 3" intakes, stock upper pipes, Alpha street fmic, HKS BOV vent to atmosphere, dp/mp/exhaust. Weather: 64f, Engine oil temp: 174F, Coolant: 172F, Trans oil temp: 162F

I'm sharing the logs with you first before hitting up my tuner. I value your opinions more, and would like to see what you think the problem is so I can discuss with my tuner by letting him know what's really wrong, and not have him brush the issue as if I don't know what's happening.

just realized, forgot to include Throttle Pos% & Theo PW, are you still able to identify the issue? trying to avoid re-datalogging and throwing the car on limp again
Thanks in dynamic advance haha

View attachment 401632 View attachment 401633
^after my 1st log (datalog2) w/ cut

Dump your tuner or run water methanol injection to bring that octane up. Or better yet, do both.

 

[majj35]

You're tune is running too much ignition timing for pump fuel, which is even worse because it's 91oct pump fuel. No need to even comment on other aspects of the tune. If you want to damage your engine I recommend staying with the current tuner.

Can i know what else? I just want to understand what im seeing more in the logs like:

-When is it running too much ignition timing, in correlation of what also? (which row) and what would/should be a normal range for ignition timing be? (note my upgraded GSC Cams S1) ,

-What else looks off? Wastegate duty%? Researching and trying to learn for my benefit.. if anyone has a healthy datalog to share plz do..comparing to learn about healthy parameters.

Edit: I opened up an old log during my FBO times, looking to compare vs the one i have.. i noticed as you said the "Ign timing" difference , also wastegate? is this what you mean?

 

[240Z TwinTurbo]

You were given the proper advice, which was to swap tuners because your engine has significant knock (-5 DA) due to excessive ignition timing on 91 octane. I'm not going to provide further critique of this tune because it's not my job to do your tuners job when you paid him for his services. Swap tuners or don't swap tuners, your car and your decision.


Here are my most recent dyno results with SIR Gen2 GTX3071r on 93 octane pump fuel, stock engine.