Using water-only system year-round? Feedback?

[FI_Rubicon]

Originally Posted by Flr Power

I have been dyno tuning for 12 years. What I have found is that ''tuners'' are often just dyno operator. They are not that good at tuning even after many years. A lot of dyno operator can tune WOT pretty good but they lack in all the many engine table parameters that can make an engine reliable and or win races.

A dyno is truly the best way to find optimum advance since the conditions will be perfect to measure. When you don't have access to a dyno you are required to tune on the same day, same stretch of road, same wind condition and start each run at an exact same speed. Some guys also use an accelerometer to complement tuning.

That's how I started until I realised I could not get accurate enough. It was also very time consuming to reach a good tune. I know you spray a lot yourself so you could even have past MBT. If that is the case then expect the engine bearings and headgasket to be short lived just like FI_Rubicon...

Definitely agree and appreciate your dedication and ability to tune outside of WOT.

Interestingly, nobody has called your experience or dyno tuning in general into question in this thread. If anything, I am asking you to back up your statements.

A race car absolutely belongs on a dyno. No question. At the same time, my street driven Jeep will probably live a full life without engine failure, even if it never sees a dyno and despite your naysaying. Even just slapping an aftermarket blower on a stock motor will increase stress to the head gasket and crank bearings.

You have my respect as someone who goes beyond being just a dyno (read: machine) operator. Myself, I was a fully certified and factory trained Mazda/Subaru tech. Worked on all of their first generation FI cars and I modded rotaries in the early days too. I also had a California smog license, which is difficult to attain and even once you get it you still need to know how to make a car run correctly and pass smog. I can also appreciate your path to seeking more HP and wisdom etc by getting a dyno. If I had a shop and a dyno, I'd be living on the thing with a laptop collecting and analyzing logs, tuning cars and eeking out every last bit.

Still.... it would be great to better understand what actual failures have occurred in the context of a street driven vehicle. Sure blowing a head gaskets or increasing bearing wear sounds great on paper and in theory. Maybe it can even happen on a race car. Where is the actual and factual data to back that up? The question is still out there.... How many engines have you personally seen fail as a result of getting MBT wrong with WI where it is not also accompanied by knock? Lots of folks are tuning by knock and you know it. While it may not be perfect, it does work for folks without a dyno. Where are the accompanying reports of folks killing their engines with WI/WMI where they tuned on knock? There really is not even any data out there to suggest just putting a blower on an otherwise stock NA motor will decrease engine life and there is lot of naysaying around that. Still no actual cases of failure or reduced engine life to back it up where some other factor cannot be identified as the cause.

It would also be interesting to understand why you feel that I am necessarily over-spraying and getting MBT so wildy wrong that I will incur engine damage.

[Flr Power]

Wow. Listen, I intervened to prevent people thinking it is normal to tune to knock with WI. Now, that does not mean we can not tune an engine as close to knock as possible. Like when the fuel has too low of an octane to support the cylinder combustion pressure leading to fuel auto ignition (knock).

Tuning to MBT (except for idle) should be the ultimate goal as it gets your engine a fuel efficient (torque) burner. I have seen a few engines blown using WI and guess what, all failures were a combination of not enough WI and TOO much timing. So these engines ran for a while before failing. These were not my tunes but I saw the maps afterwards.

Again, if you operate a 4 liter engine to 400 hp and then ask a 2L engine to crank 1200hp then guess what an excess of just say 5 degrees past MBT will do... It just won't last as long. You also lose power past MBT.

Can you tell us how much power the engine is producing?
What is the total WI volume you are spraying?

[parmas]

Originally Posted by Flr Power

More than likely the crank pulley bolt was improperly torqued to the right value or the bolt is the wrong type and or wrong steel used.

The bolt is Toyota Oem although it was made for s 105bhp engine not 300bhp+

I torqued the bolt myself 4years ago never gave me trouble. I also used a decent locktite with threading

[Flr Power]

Tripling the hp would not mean the bolts sees 3x the stress imposed on it. Normaly, the crankshaft pulley bolt sees abnormal stress when an imbalance occur between the pulley and crankshaft. Is the pulley vibration free when you look at it and rev the engine?

Also some drivers can be pretty hard when they force the engine acceleration rate to change abruptly. Like when upshifting, downshifting and releasing the clutch very fast.

[parmas]

Originally Posted by Flr Power

Wow. Listen, I intervened to prevent people thinking it is normal to tune to knock with WI. Now, that does not mean we can not tune an engine as close to knock as possible. Like when the fuel has too low of an octane to support the cylinder combustion pressure leading to fuel auto ignition (knock).

AGREED

Tuning to MBT (except for idle) should be the ultimate goal as it gets your engine a fuel efficient (torque) burner. I have seen a few engines blown using WI and guess what, all failures were a combination of not enough WI and TOO much timing. So these engines ran for a while before failing. These were not my tunes but I saw the maps afterwards.

AGREED

Again, if you operate a 4 liter engine to 400 hp and then ask a 2L engine to crank 1200hp then guess what an excess of just say 5 degrees past MBT will do... It just won't last as long. You also lose power past MBT.

AGREED

Can you tell us how much power the engine is producing?
What is the total WI volume you are spraying?

From your experience on the dyno can you tell us how can we tune an engine correctly on the street with all the safety tips how to understand we are near or over MBT ?

[rotrex]

If you advance and you both get no knock and power rises in manner you feel it, your have not hit MBT.
If power stops rising in a way you feel it, but still no knock, stop advancing, even go back a tad. If you don't feel power rising, any extra power won't mater for street use or track days anyhow.

you won't get to MBT this way, but within a few %. So forget chasing the last 10HP on a 400 HP engine that is not knock limited (no knock before MBT) on the street.

Only on a dyno, best a engine or hub dyno, you can observe the function of advance vs. power/torque for any given rpm.

If you have a very good street dyno software, you may come close if you have a suitable flat and straight road without enforcement.


On the street unless there is no speed limit, you will not generate the heat you do on track.
So if you street map, but intend to hit a track, pull timing at higher intake air temps and bring a laptop to the track to correct if knock occurs.

PS I use a J&S safeguard knock control system with display. This helps a lot as it reacts very fast and reduces loads a lot shall the combustion go haywire.

[Flr Power]

Very well said rotrex. parmas, since you spray a lot of WM for the power produced, the engine will not knock past MBT. So be cautious about using knock detection to find MBT.

[parmas]

Originally Posted by rotrex

If you advance and you both get no knock and power rises in manner you feel it, your have not hit MBT.
If power stops rising in a way you feel it, but still no knock, stop advancing, even go back a tad. If you don't feel power rising, any extra power won't mater for street use or track days anyhow.

AGREED

you won't get to MBT this way, but within a few %. So forget chasing the last 10HP on a 400 HP engine that is not knock limited (no knock before MBT) on the street.

MAYBE WITH FINE TUNING AND TIME...

Only on a dyno, best a engine or hub dyno, you can observe the function of advance vs. power/torque for any given rpm.

AGREED

If you have a very good street dyno software, you may come close if you have a suitable flat and straight road without enforcement.

On the street unless there is no speed limit, you will not generate the heat you do on track.
So if you street map, but intend to hit a track, pull timing at higher intake air temps and bring a laptop to the track to correct if knock occurs.

AGREED


PS I use a J&S safeguard knock control system with display. This helps a lot as it reacts very fast and reduces loads a lot shall the combustion go haywire.

Unfortunately I do not have a knock control system. I tried to find one but never decided.

[FI_Rubicon]

Flr Power, sorry for any sand kicking on my part. I was and still am not convinced that I am in a danger zone with my street drive Jeep.

Hopefully I am correctly jetted since I followed the Aquamist guidance.

And thanks for asking more about my system.

I am running a single Aquamist 1.2mm jet with 50/50. My target is more like 17% of fuel versus a full 20% and I have the extra 0.4mm-b jet to get me there.

I sized more based on injectors, which are GM/AC Delco injectors rated at 54 lbs per hour. I converted that 567cc/min and sized my 6 cyl. based on that.

Sizing based on HP, I target 1.375 to 1.5 times HP and came up with the same jet sizes. This kit is claimed by the vendor to put out 317rwhp, which is on par with other similar bolt on superchargers for this engine. It is also widely believed that Jeep Wranglers get a 33% drivetrain loss and this is also perpetuated by one of the more popular Jeep tuners out there which has dynoed may stock and FI jeeps.

I do appreciate any feedback on the sizing. Again, I use 1.2mm for 50/50 and a 0.9mm for pure water. I also have a 1.0mm for using with a mix somewhere in between that.

What do you make of the 11 year old posts in this thread? Numbers 54 through 57? It was a good read. Not sure if tuning methods have changed much since those posts. Comments?

http://www.aquamist.co.uk/forum2/vbu...p?t=436&page=6

In the above thread, it is mentioned that knock sensors may not even be working effectively if even at all at higher RPMs. In my case, the Jeep won't be going past ~5,700 RPM very often anyway when I am not pulling logs.

Edit: Also, FWIW, I did notice what I thought was increasing amounts of HP (butt dyno) until about 7 degrees of advance. In light of all this conversation, I backed off my advance by a degree back to 7 since I could not really feel any difference going past that point. No substitute for a real dyno pull.

Also the more I read about WI/WMI, the more that I find I do NOT know.

[Flr Power]

The best way to be sure you have the correct ignition advance is to use fast cylinder pressure transducers. The second best is a dynometer.

The ability for an engine to enter knock zone is pretty much directly linked to PCP (peak combustion pressure) after fuel is ignited which is also linked to the fuel octane you are using and the engine Compression Ratio. I am pretty sure you know all that...

So are you in a danger zone? Nobody knows unless properly tested. I think the sizing you are using will not let you maximise timing advance but that does not mean it is wrong. Some people use WM to get a bit more safe boost and or timing advance.

But if you are trying to maximise your set up by advancing to MBT then you would require a dyno or very good datalogging software and hardware with a very meticulous testing method. But even then you won't be able to control wind speed changes that will affect the readings. rotrex also wrote how to do it on the street...

I will agree with you though, when you have a relatively low specific output engine, if the engine does not knock, even if you have past MBT by a couple degrees on your setup, should not matter. lol
The cumulative damage will be slow...