Visconti Tuning - Latest BRZ Flash Info

[OrbitalEllipses]

Originally Posted by Calum

Those logs I posted a few pages back were on the stage 1 tune. I do hope you're right that everything is ok, but I implore you to check.

True for any tuner. It seems like people don't treat what is arguably largest purchase they'll make outside of a house with the respect it requires.

[Fast_Freddy]

Originally Posted by s2d4

Runs 93 on 91 tune?

Ok....

No, 93 on JV stg II 93 octane remote dyno tune.

Originally Posted by mikalem

I also have had the chance to try out multiple vendors and I can say my experience with Johns tune is similar - his base 93 map just seems too aggressive - I have seen cases where just at normal highway cruise the car would log a series of knock events, just negative 1 sometimes, but the AM would fall from 1 down to .4 and stay there for a bit. Since he has the AM set to 1 by default the car constantly is fighting to try and bring it up. John seemed to want to blame it on bad gas, however other tunes on the same tank didn't display the same problem so I don't really think that's the case and I can just conclude that his tune is too aggressive for a daily driver NA car.

Another note - torque's knock detector isn't all that accurate compared to the KC/AM values recorded by EcuTek - if you are going to continue running Johns tune I would suggest getting a cable to do some logging of your normal day to day operation, just to verify you are not having the same problems.

I wanted to give John the benefit of the doubt, mostly because I spent a good deal of money with him, but hindsight being 20/20 I can't say I would use his services again, there are other better cheaper options available. YMMV.

Sent from my SGH-M919 using Tapatalk

Thanks. I will consider your experience and advice if and when I have reason to get a new tune.

Originally Posted by vgi

another words you don't know as you have never logged it.

i think you should worry even if you're not FI. ever herd about DI seals melting on stock cars / stock tunes?

The tune was logged on the dyno, reviewed and adjusted by JV.


I've heard of a handful of cases of DI issues on stock tune cars when raced heavily with the old ECU programming. I have the latest ECU program as a base. Do you fully understand how the stock ECU programming is designed to handle ignition timing advance? Hint: It requires a lot of knock correction.

Originally Posted by Calum

Those logs I posted a few pages back were on the stage 1 tune. I do hope you're right that everything is ok, but I implore you to check.

I appreciate your concern but I do believe that most people underestimate the capabilities of the Denso ECU and knock sensor.


Has anyone ever logged a stock tune to see what the KC looks like?

[Td-d]

I'm going to tactfully avoid any potential landmines in this thread, but I have to ask some questions:

Originally Posted by Fast_Freddy

Do you fully understand how the stock ECU programming is designed to handle ignition timing advance? Hint: It requires a lot of knock correction.

I'm not sure what exactly you mean by this? The OEM knock control strategy is well understood: http://www.romraider.com/forum/viewt...hp?f=25&t=1840 - but I'm not sure what the statement above means?

Originally Posted by Fast_Freddy

I appreciate your concern but I do believe that most people underestimate the capabilities of the Denso ECU and knock sensor.

And I think people forget that we drive non-luxury vehicles (I hate the term econo-box) where costs and functionality are always a trade-off. Knock sensors are far from infallible - that's why any tuner worth his salt will use Det cans and not just rely on the ECU knock parameters. There is a complex set of logic around noise filtering that make the knock sensor work to the best of its ability - but always keep in mind that once you tune a vehicle, you are stepping outside of the margins of safety that the OEM put in place, and potentially the specifications of any piece of hardware on the vehicle.

Originally Posted by Fast_Freddy

Has anyone ever logged a stock tune to see what the KC looks like?

Should be interesting - would not surprise me if there is knock, on poorer grade gasoline. Some JDM subarus that landed up in the Australian market were notorious for severe knock, from the factory - since they were set up for higher octane fuel.

Bottom line is that knock control is a safe-guard - but a relatively knock free tune to start with is preferable. Prevention is better than cure - and if you're logging knock, especially in higher load areas, it will eventually catch up with your engine.

[jamesm]

Originally Posted by Td-d

And I think people forget that we drive non-luxury vehicles (I hate the term econo-box) where costs and functionality are always a trade-off. Knock sensors are far from infallible - that's why any tuner worth his salt will use Det cans and not just rely on the ECU knock parameters. There is a complex set of logic around noise filtering that make the knock sensor work to the best of its ability - but always keep in mind that once you tune a vehicle, you are stepping outside of the margins of safety that the OEM put in place, and potentially the specifications of any piece of hardware on the vehicle.

as someone who is currently in the process of learning (often the hard way) how to tune a car from scratch, i can assure you truer words have never been spoken. that's a+ advice. i wasted a whoooooole lot of time before i discovered how to make electronic det cans from wal mart parts lol.

[jamesm]

just my .02 on the issue is that nowhere else in the subaru tuning community will you hear that consistent knock correction is 'ok' or 'the way it's supposed to be'. it doesn't make sense that it would be.

knock correction exists to mitigate the problems caused by necessarily sub-optimal tuning (from the factory). it's what you're paying to eliminate with a custom tune. you know what type of fuel you use, and what the knock threshold of your exact car for that exact fuel under your conditions is. the whole point of the tune is that is allows permanent correction for the variables the ecu has to deal with in realtime with corrections. it's why we scale maf sensors and tweak injector latency and try to make sure our flkc is clear. it's the entire. effing. point.

so no, your aftermarket tune done specific to your vehicle should not show significant, real, repeatable knock correction, and certainly not at higher loads.

i'll also note that from what i've seen ecutek logging only shows you 2/3 of the knock control picture. i haven't seen where you can view flkc with their logging software. so all you have to go on is fbkc (which is noisy at low loads and not often active at wot where load is steady) and rough correction (iam), but rough correction itself is easily (and commonly from what i've seen) disabled by tuners.

[vgi]

I recon just leave the guy alone with his awesome +17WHP, +10lbs TQ and no TQ dip tune, it's his car and he knows better anyway.

[brn12345]

Originally Posted by Fast_Freddy

No, 93 on JV stg II 93 octane remote dyno tune.

Has anyone ever logged a stock tune to see what the KC looks like?

Yes I have logged on the following:
-Stock tune on pump gas (95 RON but I have my doubts)
-Generic tune on pump gas (95 RON but I have my doubts)
-Generic tune on VP Motorsport 103

I can tell you that on both the stock tune and the generic tune on pump gas that the car does exhibit knock. The IAM in both cases moves to 0.2-0.3 in about a day. I have extensively logged this and can say that there is no knock on high load / full throttle runs. All the knock logged is in the part throttle normal cruise area and throttle tip in which results in overall timing being retarded. Fine Learning Knock Correction (as a table) is also being populated which says that the car is actively pulling timing.

On the Motorsport 103 IAM is rock steady at 1 and does not change. There is no knock what so ever and the FLKC table is all 0's. The car is noticeably quicker, smoother, and more crisp. Exhaust tone is sharper and the motor screams in the top end. If I could I would run this fuel everyday as this is how the car is supposed to run.

From this I will make an assumption that the stock tune is aggressive in low and part throttle (maybe for emissions?) and does knock when we have bad or low octane fuel. This results in the global timing to be retarded (due to IAM). As a compromise, I have adjusted the Advance tables lower and increased the Base timing tables in the 6000-7700rpm range. What this allows for is maximum power at full throttle even when IAM is very low.

If anyone wants to see these logs kindly PM me.

[Fast_Freddy]

Originally Posted by Td-d

I'm going to tactfully avoid any potential landmines in this thread, but I have to ask some questions:

I'm not sure what exactly you mean by this? The OEM knock control strategy is well understood: http://www.romraider.com/forum/viewt...hp?f=25&t=1840 - but I'm not sure what the statement above means?


I'm not a tuner nor an expert on tuning. What I think I understand about general Denso ignition timing advance strategy was learned from Toyota and Toyota tuners. AFAIK the ECU pretty much advances timing until knock is detected at which point timing is retarded until knocking stops at which point timing is advanced again until knock is detected and so on. How else could they achieve optimal spark timing across the wide range of fuel grades, altitude and weather variations the car will be subjected to?

Thanks for the Romraider link. Great info that I had not seen before.

And I think people forget that we drive non-luxury vehicles (I hate the term econo-box) where costs and functionality are always a trade-off. Knock sensors are far from infallible - that's why any tuner worth his salt will use Det cans and not just rely on the ECU knock parameters. There is a complex set of logic around noise filtering that make the knock sensor work to the best of its ability - but always keep in mind that once you tune a vehicle, you are stepping outside of the margins of safety that the OEM put in place, and potentially the specifications of any piece of hardware on the vehicle.


You're not suggesting that our knock sensors or ECUs are cheaper versions than those found in Outbacks and Solaras? I don't agree with that. I do agree with your other points but would like to add that this is true for any tune, not just JV. Speaking of which, aren't there literally hundreds of people running JV tunes out there? Any reports of tune-related engine damage?


Should be interesting - would not surprise me if there is knock, on poorer grade gasoline. Some JDM subarus that landed up in the Australian market were notorious for severe knock, from the factory - since they were set up for higher octane fuel.

Bottom line is that knock control is a safe-guard - but a relatively knock free tune to start with is preferable. Prevention is better than cure - and if you're logging knock, especially in higher load areas, it will eventually catch up with your engine.

I may be wrong but what I learned in the 2AZFE tuning world was that the biggest problem with high KC was that the ECU pulled too much timing before adding it back which lost some power. It was best to minimize the amount of KC but not to eliminate it. The only case I know of where a N/A 2AZFE was destroyed by knock was when the knock sensor came loose on a bone stock engine and it self destructed due to the OEM timing strategy. My own turbo experiment yielded gains of 125whp/125ft lbs at 6psi with nothing but 20% larger fuel injectors and 93 fuel for tuning. No piggyhack, no ECU flash, nothing but a AFR sensor signal modifier for AFR enrichment while in closed loop. I raced that engine many times and daily drove it for over 40k miles without any issues.

Originally Posted by vgi

I recon just leave the guy alone with his awesome +17WHP, +10lbs TQ and no TQ dip tune, it's his car and he knows better anyway.

Don't be an ass. If you're so sure that I'm wrong, please explain why.

Originally Posted by brn12345

Yes I have logged on the following:
-Stock tune on pump gas (95 RON but I have my doubts)
-Generic tune on pump gas (95 RON but I have my doubts)
-Generic tune on VP Motorsport 103

I can tell you that on both the stock tune and the generic tune on pump gas that the car does exhibit knock. The IAM in both cases moves to 0.2-0.3 in about a day. I have extensively logged this and can say that there is no knock on high load / full throttle runs. All the knock logged is in the part throttle normal cruise area and throttle tip in which results in overall timing being retarded. Fine Learning Knock Correction (as a table) is also being populated which says that the car is actively pulling timing.

On the Motorsport 103 IAM is rock steady at 1 and does not change. There is no knock what so ever and the FLKC table is all 0's. The car is noticeably quicker, smoother, and more crisp. Exhaust tone is sharper and the motor screams in the top end. If I could I would run this fuel everyday as this is how the car is supposed to run.

From this I will make an assumption that the stock tune is aggressive in low and part throttle (maybe for emissions?) and does knock when we have bad or low octane fuel. This results in the global timing to be retarded (due to IAM). As a compromise, I have adjusted the Advance tables lower and increased the Base timing tables in the 6000-7700rpm range. What this allows for is maximum power at full throttle even when IAM is very low.

If anyone wants to see these logs kindly PM me.

Great info. Thank you.

[Fast_Freddy]

So basically what I'm hearing repeated here is that running any JV tune is dangerous and not recommended. That being the case, can anyone please post some examples of JV tunes causing engine damage? TIA.

[Td-d]

Originally Posted by Fast_Freddy

AFAIK the ECU pretty much advances timing until knock is detected at which point timing is retarded until knocking stops at which point timing is advanced again until knock is detected and so on. How else could they achieve ideal spark timing across the wide range of fuel grades, altitude and weather variations the car will be subjected to?

Thanks for the link. Great info that I had not seen before. At a glance it looks as though IAM is much like long term fuel trim (LTFT) and FLKC is much like STFT.

No prob, there's a lot of information hidden on the RR forums over the years. Not really - it's a more reactive process - basically you have the base timing, and then the knock correction advance, compensated for with the various parameters (i.e. FBKC, FLKC, and IAM as a multiplier) and that's the timing. There are 3 knock control 'levers' - IAM is the so-called 'rough correction' mode, and will drop all timing in the KCA by a %. FLKC is learnt over time and stored in ROM defined 'cells' whilst FBKC is immediate.

Originally Posted by Fast_Freddy

You're not suggesting that our knock sensors or ECUs are cheaper versions than those found in Outbacks and Solaras? I don't agree with that. I do agree with your other points but would like to add that this is true for any tune, not just JV. Speaking of which, aren't there literally hundreds of people running JV tunes out there? Any reports of tune-related engine damage?

Not suggesting that, nope - I haven't seen the part numbers, but I would not be surprised if it is the same knock sensor that is used across most of the Subaru platforms. Just saying that consumer grade knock sensors have their limitations. On JV's tunes - really, I can't comment, and frankly am not interested in commenting - I avoid internet drama like the plague Besides, I'm half way across the world (literally 8000 miles!). I'm here for the techie info...

Originally Posted by Fast_Freddy

I may be wrong but what I learned in the 2AZFE tuning world was that the biggest problem with high KC was that the ECU pulled too much timing before adding it back which lost some power. It was best to minimize the amount of KC but not to eliminate it. The only case I know of where a N/A 2AZFE was destroyed by knock was when the knock sensor came loose on a bone stock engine and it self destructed due to the OEM timing strategy. My own turbo experiment yielded gains of 125whp/125ft lbs at 6psi with nothing but 20% larger fuel injectors and 93 fuel for tuning. No piggyhack, no ECU flash, nothing but a AFR sensor signal modifier for AFR enrichment while in closed loop. I raced that engine many times and daily drove it for over 40k miles without any issues.

I would agree that on an N/A platform it's less likely to as big a problem (I don't own a BRZ incidently, have an STI). On FI, due to the nature of Subaru's pistons (hypereutectic, not cast) and the compromises made for emissions over the years, on-going knock is bad news, and will likely take the rings out, if not worse. But I cannot (and won't) pretend to know much about the FA20 - there are smarter people out there! I would expect these engine to be more not less knock resistant given the direct injection into the chambers.

[s2d4]

Originally Posted by Fast_Freddy

So basically what I'm hearing repeated here is that running any JV tune is dangerous and not recommended. That being the case, can anyone please post some examples of JV tunes causing engine damage? TIA.

I've seen people posting about the excessive knocks for probably a year already. No smart person would ignore that and keep running these tunes until engine failure. Have you just been dismissing/ignoring them?
I'll let them chime in but the info you are after had already been posted.

[Fast_Freddy]

Originally Posted by Td-d

No prob, there's a lot of information hidden on the RR forums over the years. Not really - it's a more reactive process - basically you have the base timing, and then the knock correction advance, compensated for with the various parameters (i.e. FBKC, FLKC, and IAM as a multiplier) and that's the timing. There are 3 knock control 'levers' - IAM is the so-called 'rough correction' mode, and will drop all timing in the KCA by a %. FLKC is learnt over time and stored in ROM defined 'cells' whilst FBKC is immediate.

Thanks! Excellent explanation. I've speculated for some time now that ignition timing was learned and adjustments stored much like fuel trims and now you've confirmed it for me. FLKC is like LTFT, FBKC is like STFT and IAM is a failsafe not really needed for fuel trimming.

Not suggesting that, nope - I haven't seen the part numbers, but I would not be surprised if it is the same knock sensor that is used across most of the Subaru platforms. Just saying that consumer grade knock sensors have their limitations. On JV's tunes - really, I can't comment, and frankly am not interested in commenting - I avoid internet drama like the plague Besides, I'm half way across the world (literally 8000 miles!). I'm here for the techie info...

Agreed on the knock sensors but to my old school car guy mentality, even consumer grade sensor/ECU components impress me. I started out with a 1968 vintage 396 Chevy BB and TBH I prefer modern EM systems to the old distributors and points.

I would agree that on an N/A platform it's less likely to as big a problem (I don't own a BRZ incidently, have an STI). On FI, due to the nature of Subaru's pistons (hypereutectic, not cast) and the compromises made for emissions over the years, on-going knock is bad news, and will likely take the rings out, if not worse. But I cannot (and won't) pretend to know much about the FA20 - there are smarter people out there! I would expect these engine to be more not less knock resistant given the direct injection into the chambers.

I'm no FA20 expert either but that makes perfect sense to me. As for JV, I can't help but feel that it was his sometimes caustic personality that has made him such a pariah on this forum much more so than his tuning capabilities.

[Fast_Freddy]

Originally Posted by s2d4

I've seen people posting about the excessive knocks for probably a year already. No smart person would ignore that and keep running these tunes until engine failure. Have you just been dismissing/ignoring them?
I'll let them chime in but the info you are after had already been posted.

I too have seen amateur tuners posting about what they consider to be excessive knock correction. Unfortunately, anyone with an ECUTek cable and a laptop is an "amateur tuner", free to post about his excessive knock correction.


Are you really saying that my JV tune is dangerous and that if I continue to run it I will eventually suffer engine failure? Sounds like a bet is in order.

[s2d4]

Originally Posted by Fast_Freddy

I too have seen amateur tuners posting about what they consider to be excessive knock correction. Unfortunately, anyone with an ECUTek cable and a laptop is an "amateur tuner", free to post about his excessive knock correction.


Are you really saying that my JV tune is dangerous and that if I continue to run it I will eventually suffer engine failure? Sounds like a bet is in order.

No, evidently people shouldn't bother doing any logging because there is no need to do it for amateur tuners, and certainly not required when a master tuner like JV does tunes.

As for the bet, you win.