Here's the REAL debate: NSX or Vaporcar?

 

I can't believe this thread even went beyond one page - we're beating a dead horse with another dead horse. If you can't afford the couple of extra bucks to use premium, you have bigger problems that need to be addressed.

All this "engineering" that's been going on in this thread has already been done in 2003, and probably again in 2006, by people who know a lot more about the car than any of us do.

 

put premium in the ford transit for work today...my co-worker never has. He was like...WHOAH, that really woke the truck up!

 

A few things that need to be said.

Do not compare compression ratio and octane between DI and port injected cars. A direct injection car can run a much higher compression ratio and/or boost level for a given octane than a port injected engine. My BMW is somewhere around 11:1 and currently runs 22psi boost on 91. My GN (port injected) can run 17psi with an 8.5:1 comp ratio.

Keep in mind effective compression ratio is what matters, not mechanical ratio. Cam and head design have a big role. A small cammed car will have more compression while running at low engine speeds.


If the car does not detonate on 87, 91 will do nothing.

The knock sensor is reactive, not proactive. It can only react to detonation, it can't prevent it. Relying on the knock sensor as a form of tuning by either an individual or a manufacturer is wrong. The knock sensor is there to soften the blow for a short period of time, such as the owner accidentally running 87 once or twice.

Once detonation starts, much more timing has to be pulled to stop it than if it never started.

Minor detonation that's inaudible usually will not result in broken parts but it will take its toll on rings, pistons, head gaskets, and rod hearings over time.

Retarded timing significantly raises exhaust gas temperature which is harder on the exhaust valves, converters, and 02 sensors. Driving around with retarded timing all the time because you refuse to run premium is not the solution.

As hp levels go up, the inaudible detonation can result in broken parts. I can't hear mine until there's about 12 degrees of knock retard occurring. By then it's too late and I have a blown head gasket.

If a car says to run premium, this is a very wise idea. Many people do not like buying cars that require premium so the manufacturer is not going to install the premium only stickers unless it's required.

The only exception is if the car knows what octane is being used and switches to a different timing map beforehand. You will lose power and mpg but the engine will be as reliable as ever.

Be happy your car is tuned for premium. It will get better mileage and make more power than the identical car tuned for 87.

Lower octane fuel does not mean more carbon buildup nor does it mean it's faster or slower burning or has more or less energy content than higher octane fuel. The only truth to the carbon buildup is premium usually has more detergents, sometimes 2-3x more than regular. For those with DI engines you better use premium whether it requires it or not, especially Shell.

Again, do not compare DI to Port injected cars to support your argument. It's apples to oranges and its been done several times in this thread.

The TL will detonate on 87. It might not do it constantly but it will detonate, period. Your ears are not the best tool for hearing the detonation, keep that in mind.

 

Matt. I miss you.
School these suckas.

 

Matt

 

Assuming the manufacturer knows nothing about the car (?) then why stop at fuel octane? Using that logic why not save a few bucks and run lower quality oil? Lower quality plugs? Etc. Personaly we bought our car to enjoy, not trash. IMHO using non-recommended fuel is a risk we won't take.

Moderator, can we please close this thread?

 

I tried a couple gallons of 87 in the cool of winter in my '06 TL mt. It behaves with an easy throttle like 91. On a hill in a gear or two higher than normal, it pings until the knock sensor catches up and corrects it (mostly). I'll try 89 sometime, but I doubt there is any good choice but 91.........or even 93 if you can get it.

 

Haha you guys.

Serious question - is there a way to monitor detonation using Torque + ELM327?

I've been collecting data on timing advance, rpm, and load so I can post that, but I don't think it tells the full story anyway. I'd love to collect data on detonations.

Any of the 87 guys have that Knock Detector plugin for Torque? Have you tried using that? If so, at what RPM range did you use it?

 

 

Joe...

 

AFAIK, there is no PID for knock detector activation, so detonation can't be monitored directly via ODB-II.

Yes, I've run several hard pulls to just short of redline in 3rd gear and the plugin did not detect detonation. Some of the pulls were on a decent uphill stretch as well. Temp was ~40F.

 

^^^^ this!

 

I wonder how that plugin works and if the developer would put the source code out there. Essentially he's using the same data that's already on the CAN Bus but is able to somehow meaningfully interpret it to determine if knocking is occurring. I can't access the play store at work, I'll check it out when I get home.

 

^^^^^^^


https://acurazine.com/forums/third-g.../#post15318725

 

Any new discoveries? Please post results. I'm antsy.

Also, self quoting...

 

Memory > me.

Hoping someone can pop in and give us a good way of reliably and repeatably measuring detonations.

 

"In order to work on all car models Knock Detector uses heuristic algorithm to find detonations. It is based on analysis of timing advance, throttle, revs and speed. On some ECUs it may report knocks but the reason could be timing retard because of specific factory tune.
Knock Detector will not report minor car specific knock events so it can also miss some detonations. However it will report ECU learned detonations. Such knock events will likely disappear at some moment. Detonations can be real or fake, they can appear and disappear, so there is no reason to worry if such are reported. Detonation may be caused just by depressing the throttle at high revs. Some stock ECUs pull timing 0.5 - 1.00 even on WOT so fake knock will be detected.
Engine coolant and intake air temperaturesare also monitored as major knock factors. Avoid spirited driving or testing when both values are not green - too cold or too hot temperatures can cause detonations.

More features are coming soon. Used every day on my heavily modified Subaru STI ! Drive safe and have fun !"

https://play.google.com/store/apps/details?id=com.nosoftskills.kd


C'mon Vlad, close enough

 

Haha thanks man. I can't visit the play store at work.

Seems that this feature is pretty unreliable then. That's disappointing.

 

Maybe, maybe not. Pretty sure it's measuring those parameters and like it says, uses heuristics to interpret whether a timing retard is due to engine load or due to detonation. That's the best you can ask for since there is no OBD PID for knock sensor activation (unless there's an unpublished extended PID set for Acura).

There's no way to really know for sure though. And no way to directly measuring knock/detonation via OBD either. The app is basically doing what we are trying to do manually by recording comparable engine load/rpm/timing advance between 87 and 91.

 

I haven't used it for 87 octane, but I've used the Knock Detector plugin for Torque. I don't think it's an accurate plugin. I think you have to keep it in 1st gear and keep your foot to the ground and let the car bounce off the rev limiter for 2-3 seconds til the plugin even says "Throttle" 100%.

I've floored it until 80mph and it showed Throttle position at 75%, so idk if that plugin is credible.

 

Again, I can't vouch for the accuracy of the plugin, but that's not the right way to run the test using the plug in...

 

You're right. But if it can't detect my throttle position, it just loses credibility; we can agree on that right?

EDIT: I'll tell you this; while I was test beater cars, I used obd2 bluetooth paired with Torque, and I scanned 3 cylinders misfiring codes, this was on a 96 camry V6.

I launch the Knock Detector plugin that came with Torque, and I floored it. I started feeling the engine misfire; I can describe it as you putting your foot down, and slightly let go from WOT. It's like the RPM's would climb and then go back a little, then climb again.

The plugin? Didn't detect anything; end edit. then again, knocking and misfiring might not be related.....lolol

 

Sounds like people need to get Hondata FlashPro . I tried running 1 tank of 87 for shits and giggles since it was extremely cold in WI. The OEM knock sensor picked up 2 and 3 knocks during two 3rd gear pulls, if I had FlashPro handy I could tell you which cylinders experienced knock. I was watching this via phone app to let me know if I saw 5 to 10 knocks to abort the pull.

Just driving around normally in extremely cold ambient conditions with 87 the PCM didn't report any knock counts. If the PCM doesn't see it, it doesn't count. I am now happy to say I am back on a healthy diet 91 octane dino juice.

 

The throttle position PID will most likely never read 100% on any car, regardless pedal position or throttle plate position. Here's the ISO spec to help you understand why it will never read 100%:

Absolute throttle position (not “relative” or “learned” throttle position) shall be displayed as a normalised value, scaled from 0 to 100%. For example, if a 0 to 5.0 volt sensor is used (uses a 5.0 volt reference voltage), and the closed throttle position is a 1.0 volts, TP shall display (1.0 / 5.0) = 20% at closed throttle and 50% at 2.5 volts. Throttle position at idle will usually indicate greater than 0%, and throttle position at wide open throttle will usually indicate less than 100%.
For systems where the output is proportional to the input voltage, this value is the percent of maximum input reference voltage. For systems where the output is inversely proportional to the input voltage, this value is 100% minus the percent of maximum input reference voltage.

Since (AFAIK) there is no PID for knock sensor activation, how do you know the sensor activated?

How can it do this?

 

I have to check but I know the tables are active and when knock occurs the PCM is pulling timing as commanded by the tables.

The same way it knows when to inject fuel and ignite the mixture, crank position sensor.

 

But again, there is no direct input from the knock sensor to the flashpro or OBD, so you can never be certain that the knock sensor was activated based upon flashpro readings.

Huh? Again, tell me how the flashpro can tell which individual cylinder/s was/were knocking? Show me where in the manual it says it can do this.

 

Since the Flashpro flashes the ECU, I'm betting the wizards at Hondata have the ECU forward the knock sensor cylinder number to the OBD for the Flashpro to read.

 

No!! There is only one knock sensor. It doesn't know which cylinder/s is/are knocking..

 

I'm sure the ECU is using a heuristic algorithm to determine which cylinder is on its exhaust/compression stroke and correlating the knock.

 

Although I don't know for sure, I highly doubt that. I've never seen any indication that the stock ECU controls individual cylinder timing. I'm 99.9% sure it just pulls timing across the board.

 

Hondata must be selling lies then.

https://www.hondata.com/help/flashpr...r_ignition.htm

 

Again:

With the flashpro, it appears you can alter the tables by cylinder, but even then, it's not "reactive". The tables are/can be adjusted according to a specific tune, but I don't see anything about the ECU reacting "on the fly"/real time to individual cylinder knock.

 

Here's my 3rd Gear Pull on 87.

The PCM can record knock and provide the knock location based off the cylinder that is currently in the combustion cycle. I didn't say the PCM will reduce ignition timing for that cylinder, but rather global timing. You wouldn't want to alter timing very much on an individual cylinder basis since it would cause a power imbalance relative to the other cylinders.

 

He just really needs to be right...on, or off topic.

Intellectual conversation...sure. On topic? Not even close. Where are those pertinent "results"you promised us?

 

My reply that you quoted wasn't to you, just so you are aware.

A knock retard of only 3 degrees? That doesn't sound right to me. I'd think knock retard would be a lot more than that... Just saying....

 

oops wrong quote, my bad. The IAT helped out a lot.

 

 

But but but, my one liner of the heuristic algorithm bullshit, can we get that framed somewhere? Gold flew right over his head

 

It's exhausting already with him. It's all irrelevant. No idea why you guys bother being constructive and posting information pertaining to this god forsaken thread, just to be told NO, wrong, no no no no no, wrong wrong wrong. Just agree with them about what they want to hear and call it a day.