Re: Injection amount vs E85
 

Been using allot of Richards systems recently (direct port) as per your finding and others works well, but I dont know everything, never will.

Anyway yours and everyone's contributions is what its about here and why its a good place, always fun to go back and re read some of the stuff from many years before too :)

Re: Injection amount vs E85
 

Because I have got a state of the art LT10s microtech which has no knock sensors, I have to read the plugs after each tune change, which Im happy to do. Ive never once heard my setup knock by ear but its showed on the plugs, although I have heard it knock just before the water turned on before but never once its on.

So just out of curiosity does anybody check the plugs? Or does everyone rely on knock sensors etc? Only reason I ask is I was always under the assumption that knock sensor wont show pre-ignition or at least not fast enough? Not that a plug check can help once the damage is done lol.

Here is an interesting read, unless Ive missed it I could find it on this site. Once it loads its a little down the page. Cheers

https://www.sciencedirect.com/scienc...7661021502648X

Re: Injection amount vs E85
 

Preignition is usually a consequence of knock.
Unless you run extreme compression ratios or get boost spikes that woud result in instant preignition, Diesel comes to mind, it usually starts with "plain" knock. Knock tends to increase local temperatures of chamber components such as spark plug electrodes as the combustion becomes irregular and overall faster. As pressures rise faster than anticipated, chamber temperatures rise rapidly.
The longer it knocks, the hotter bits get until they are so hot they ignite the fuel before spark occurs. You have pre ignition. It is a run-away process. It starts with light knock changing to heavy knock until kaboom, you get preignition. This commonly ends in engine destruction. The entire process can at times take less than a second given enough boost and heat.

If you have a very fast knock control system, it will retard ignition within one revolution preventing the worst. My J&S safeguard worked that way. I have tried it when my priming pump of the old Aquamist race pump failed. I spit huge flames out of the exhaust of my Elise in concerto with big misfires. The J&S pulled 10 deg timing out of all 4 cylinders at once. The TurboXS knocklite also shows single and faint knock events below the audible treshhold. At first I thought it was indicating artifacts, but pulling 2 deg of timing in these spots reproducibly removed the indication.

You can data log the output of the J&S, but commonly there are only a few spots you need to correct under full load.
I have also used it to generate a suitable IAT ignition compensation table for water methanol injection on my engine.
The base settings were mapped at 20-30C IAT with short squirts of power.
The temps up to 50C were evaluated with longer and repeated pulls or during hot weather. The range to about 70C intake air temp, the highest I ever managed, then on track.
Without data logging, you cannot really do this conveniently.
If you push on without active knock controll, you'll eventualy run into trouble.

Modern ECUs have sophisticated knock control.
But for less sophiticated systems, the J&S is a viable add-on for high boost applications. I'll safe your engine eventually. I doubt that you can pull your foot fast enough of the throttle at 25PSI of boost when heavy knock occures. A small drop in fuel pressure due to starvation is all it takes to blow an engine without protection. Same for bad fuel, failing IAT sensors, etc. My Rover would not have survived it without knock controll. I have cracked a liner during a fueling issue at the bigging of mapping it myself. There wasn't more than a slight power fluctuation and it blew liters of coolant at 6000 rpm in seconds though the exhaust. It was the biggest cloud I have generated in my entire life. The fuel pump was not up to the job feeding the bigger jets leading to pressure issues. The wideband lambda sensor data together with the injector duty cycle showed this nicely. I then added a fuel pressure sensor to confirm.

Re: Injection amount vs E85
 

See the table set in my many Life Racing ECU customer cars, take note of title ;)
NOTHING in the world is more fragile than a rotary engine!!!!
And with stock standard apex seals you can not break the engine due to knock, once set up correctly with a Life Racing F88 ECU.
I record every single engine cycle (all the time on load) and the ECU has always controlled this so each firing event of the plug each event of signal from the knock sensor is recorded but more importantly acted on INSTANTLY by the ECU.......... nothing in the world I have seen works as well, the other real racing quality ECU's I personally used and owned inc Pectel MQ12 and Bosch MS5* series ECU, shit that costs $20,000 for a control unit FYI :) no Mowreck or Microwreck need apply LOL.......
https://i.imgur.com/Bz9z6Jj.jpg

Re: Injection amount vs E85
 

So it looks like not many people bother checking the plugs lol. You forgot microjunk and microwreck haha. Cheers

Re: Injection amount vs E85
 

I pull them once in a while to check uniformity and look for absence of oil contamination, but if you push boundaries it might be worth doing it more often.
Otherwise the knock sensors, ears and wideband lambda sensors tell me what is going on.
For a turbo, you need at least EGT.
If you really want to know what is going on, add a turbine rev counter and pre and optionally post turbo pressure probes.
On the intake side, measure preturbo IAT and pressure. together with post turbo temp and pressure, you can see where you are on the compressor map.

If you run charge cooling, you could measure water inlet and outlet temp plus air inlet and outlet temp. This allows to calculate CC efficiency and figure out where the bottle neck is.

Re: Injection amount vs E85
 

To actually hear knock from in the car, how bad does the knock count show? My car has 4 mufflers so its pretty quiet:).

Re: Injection amount vs E85
 

In a early Lotus Elise of the first series, you hear everything.
Can make you nervous after a big rebuild or power increase.
You can literally hear the injectors ticking at idle from the driver seat.

There is virtually no sound insulation, aluminium tub chassis, open top, mid engined. The "firewall" consists of a 3mm thick glass fibre sheet and you sit right in front of the engine for a RHD car and gain some extra 30cm distance in a LHD car. Seat mounts are short, seat padding is pretty thin, engine is partly mounted to the same alloy tub as the seat.
The engine/boot lid has big grilles to let the air out though the top. Noise also passes well. The lid is made from thin aluminium sheet and has no insulation material attached. High frequency noise easily exits the engine bay.

With a hard top or soft top fitted the cabin noise actually gets louder.


I have a radio installed, but past city speed it becomes pretty much useless. This is with a quiet muffler with its valve closed.
https://youtu.be/h-898etjgx0

Re: Injection amount vs E85
 

I am not sure what the delay is from sound generation inside combustion chamber then in air, then through various parts to your inner ear, process in your brain, then motor skills reaction and muscle movement to your leg but I would say well over 150 cycles of the engine would have happened at full revs before you can react.

Never mind that the audible knock/detonation event is much more intense that what I class a a pre ignition event trigger in the Life Racing ECU! So all up on some engine types you can say with 100% accuracy that is you are using knock ears or your own ear than that is about as archaic a method you can employ as a caveman to club a woman over the head for sex in his rape dungeon ............ sure you get the woman but she could be stone cold dead! some I guess it does not matter? :)

Many more minor events typically happen *unless you are totally wrong in calibration* or have some other part failure well before you get to pre ign or audible detonation, and the whole idea of well set up professional knock control is exactly that, you CONTROL it prior to it becoming a problem.

Never lost an engine on LR or Syvecs with my set up knock control, irrespective of root cause, loss of fuel pressure, poor fuel, some mechanical issue. Even this forum specific like latency of WI delivery say in 1st gear on a car capable of pulling 1.5g acceleration! with huge crank rpm acceleration rates and transient turbo response as per a light switch.

All of these things make it imperative that you run a proven ECU with correct knock control set up well, just my 2 cents on the topic.

Re: Injection amount vs E85
 

Here is a little sequence of events on time line to show you what I verbally described.
Keep in mind the ECU triggers instantly on register of knock despite what visual log threshold is set too, (in this cars case 300Hz is enough to capture the sound resonance through the block) even at 7500rpm on 4 stroke engine, you can see cycles recorded and event trigger of ign being pulled which instantly within one cycle of engine reduces knock........

All of this needs to be managed correctly to not allow run away knock and then pre ign from getting a foot hold and it happens so fast that there is no way in hell someone using knock ears will EVER catch let alone stop engine damage, the only reason they get away with it is the engine is either low stressed or is strong, its got nothing to do with skill or understanding (quality of equipment LOL) in them using 'knock monitoring' while tuning/fucking your engine and guessing what is happening to it under their supervision ;)

https://i.imgur.com/Q1xg9rs.jpg

https://i.imgur.com/HIOPakS.jpg

https://i.imgur.com/Tg59xpA.jpg