USA octane is different to UK octane, but principle is 100% correct of course, Frank.
This was on a 190hp na Frank. I dont think overheating is/was an issue…
Well I can only go off what the lotus engineer told me, for those asking its a fuel re set and needs to be done at a dealer, it’s not a full re flash just a re set of the fuel settings.
200f isn’t overheating since tha fans don’t come on till 207f even with a N/A setup…Do you know what your on track water temps were at the time ?
If they were over 200*f you lost power…
[quote=frank]Someone does and really what kinda Motorsport techy doesn’t have his laptop with him at all times… 
Seriously think about it the OEM ecu is designed to run on 91 octaine and car can retune its self to run on 87 octane when it detects knock… It is designed to return to it’s original tune once knock is gone… That’s the reason the knock sensor is there in the first place… retard spark and add fuel until all is well…
Maybe the tech didn’t bother to check the coolant temps because if they are over 200*f the ecu will pull timing and you will be down on power till things cool off… [/quote]
I totally agree with Franks, resetting ECU is ‘mumbo jumbo’ and such crap deserves to have no creditabability , another Urban Legend…
problem here is both are plausible, whilst we all know Gav well and he has no reason to tell us something that isn’t true, I do also see Frank’s point that the ECU learns to a point and when it detects knock will retard the timing or change the fuel to remove the knock, it will also then readjust at a later date to see if the fuel quality\knock has returned.
However if the ECU carrys on detecting knock I can see how it might end up in a “safe” state and not bother to try to return to the predefined setup.
I know full well my car has no visible signs of engine failure, but the last 2 dyno runs have shown it down some 20hp and it is now certainly slower down the long straights at tracks. I have just presumed it was down to the engine being a bit tired, but now I’m not so sure something similar hasn’t happened to my car.
[quote=ade]problem here is both are plausible, whilst we all know Gav well and he has no reason to tell us something that isn’t true, I do also see Frank’s point that the ECU learns to a point and when it detects knock will retard the timing or change the fuel to remove the knock, it will also then readjust at a later date to see if the fuel quality\knock has returned.
However if the ECU carrys on detecting knock I can see how it might end up in a “safe” state and not bother to try to return to the predefined setup.
I know full well my car has no visible signs of engine failure, but the last 2 dyno runs have shown it down some 20hp and it is now certainly slower down the long straights at tracks. I have just presumed it was down to the engine being a bit tired, butN now I’m not so sure something similar hasn’t happened to my car. [/quote]
You’ll probably find low compression, worn valves, knackered valve springs, piston slap, …
Why would a lotus engineer talk mumbo jumbo though? I did not talk to a dealer, I spoke to lotus themselves, the engineer said they remove the sensor and wrap in bubble wrap for racing I should guess that would create similar conditions to a dyno run?
I am as interested to know as the next man so why does someone else not speak to one of the guys in Motorsport or something? Should help clear things up.
Boothy
Hey listen guys, I have nothing to gain from feeding you shit, why would I? Im just trying to pass on a bit of (what I consider valuable) information I’ve learnt through running these cars for the last 5 years on track…
I’m sorry i can’t be more technical in the reasoning behind the fault, the electronic management side of it doesn’t interest me in the slightest, all I’m interested in is the driving fast bit… Fuel goes in, foot goes down is the moto!!
What I do have is good experience in mechanical equipment and having the basics taught to me how the knock sensor works I can easily see how a problem could be occurring. As I understand it the knock sensor simply bolts to a solid post externally on the engine case. It monitors the vibrations/resonance from the engine which are produced as it operates. These vibrations should fall within certain parameters, if not the engine is possibly not operating as it should and the ecu adjusts settings to try and accommodate for it.
Please someone jump in and correct me if I’m wrong, but it would suggest to me that you only need a false feed of vibrations to the knock sensor and it will play havoc with the ecu settings. Now let’s just say that with uprated mounts it causes just such a vibration frequency at 6k… Going around a track holding throttle at 6k for a period of time through a long/double apex corner is not uncommon. Keep doing that every minute and a half as you come back around are you giving the ecu any chance to readjust back to where it should be?
You have one of two choices boys.
After going through everything else on the car you can continue to sit there sractching your head as to where the power has gone or simply have your ecu reflashed/reset whichever the case and see if cures your problems.
Next time I’ll be keeping my gob shut!!
Don’t know if they do take the knock sensor off or not.
But, taking it off a closed loop knock control ecu has to be the scariest thing I’ve heard of!! By definition, the ecu is designed to adjust timing until knock is detected - and we’re not talking anything that you would hear when driving - then adjust it back, gradually reinstating the timing over a pre set number of engine cycles until the knock threshold is reached again. This cycle repeats continuosly for as long as the engine is running. Taking it off means that the ECU doesn’t hear anything wrong, so the engine would constantly be running at max allowed advance, which is fine if everything is working properly, but decidedly not when things aren’t!!
I can see them taking off the GT3 cars, but that was for other reasons, and they had far different components and maps in the ecu’s.
Hence why Frank is calling bullshit!! And I’ve got to say, agreed.
Not saying your wrong at all Gav, far from it. Your car certainly had an issue on the day that was rexolved by reflashing the ecu.
The weird thing is if the uprated engine mounts are so bad, why would Lotus sell their own version of them?
When they built that bridge in London did they think it was going to sway like it did from the off? No! Thing with that it was a noticeable problem so they cured it.
This is not something you go out in your car and go - Ooo i seem to be 20 hp down all the time, you only find it when you look for it.
As with all Motorsport parts that’s what they are - Motorsport parts… They have their own set of problems over heavily developed/tested oem fit items…
Well as I said I spoke to my local field engineer, his first reaction was. He had never heard of it but would come back to me. He did and that was his answer, why would he lie?
He did not suggest removing the sensor, he said remove the mounts.
So humour me as I am not a mechanic but what if as Gav says the resonance created by the mounts fools the knock sensor into believing its detecting knock then as you said it will do its job and bring things back into check until they are safe, but they won’t be safe as the mounts are still creating the same symptoms.
Andy , joking and bantering aside ,if your knock sensor was the issue on your car then it wouldn’t be leaner than the other two cos the last thing the designer would do is cut fuel to a detonating motor.
If it were me in your situation I’d swap the fuel pump to ensure the rail pressure is up to par.
Boothy, as JFK says, more lean under knock is not good. If its as simples as Lotus say, take off the mounts, do the ecu thing and see what it puts out.
The difficulty is going to be knowing what they do to the ecu. If they reset yours and it changes, then all is good. If they reflash with the lastest 260 map, then thats a different thing all together.
What have CN’s said about your car being down on power and appearing lean on the dyno?
It could just be a bug in the software that goes away with a reset of the fuel trims…
FWIW, there are two knock sensors available for the 2ZZ. One of them is more sensitive than the other.
Boothy, I would look at fueling issues (Fuel pump, dirty injectors). Clean the MAF sensor and throttle body while you are at it. If you are lean under WOT, there is a problem and it most probably has nothing to do with the knock sensor.
One other consideration, taking off the knock sensor and taping it anywhere is crazy. I believe the Lotus ECU is not a piece of poo and that it must have at least a knock treshold setting (Frank?). If the mounts are causing additional noise, the race team could just tweak it up. (I have TRD mounts on my MR2 and the effect on the knock sensitivity is none. I can view realtime/logged knock on my standalone ECU).
Edited to say that the 2ZZ is knock limited mostly in the 4.5k-5.5krpm region. That is on the economy cam profile.
Seriously guys the GT3 had no reason to place the knock sensor in bubble wrap since the knock function can be switched off and on with a key stroke, you can’t even get to it without removing the intake and supercharger… If a Lotus tech said he removed it and wraped it in bubble wrap he’s an idiot…
It was the noise from the TVS screws in the custom MP62 that screwed with the knock sensor along with their 10.5/1 compresion ratio…
Toyota did the original maping of the N/A 2ZZ and they set the knock maps, Lotus use the same knock maps for supercharged and N/A…
I ran my car supercharged with the knock sensor off and on and it made no difference with my 310 whp tune with hard mounts two years before Lotus offered them…
You tune with the knock sensor on and then turn it off to see where the changes are happening and make corections in the end you turn it back on and let it do it’s job…
Lotus did not turn it back on and there you go you now have the cause of all the GT3 engine failures…
Just because a guy works at Lotus doesn’t make him a tuning god trust me I know first hand since I’ve been on the dyno with a Lotus calabration engineer and we made more power when I was done dictating what I wanted to see in the tune…
I also ran cooler temps with my home brew chargecooler…
I make 620 whp with a MP62 and a turbo 2ZZ with soild mounts vibrating though the car like a old Harley with retuned stock ECU with the knock sensor turned on to it’s stock N/A seting…
[quote=JDS]
What have CN’s said about your car being down on power and appearing lean on the dyno?[/quote]
“See you in court”.
I’ll dig out my graph, by lean it was not dangerous lean just not as rich as the other two cars tested.
Fuel pump and injectors are both brand new cup260 items.
And what did CN’s say about it being down on power and the slightly leaner map? That has to be your first point of contact surely??