Discussion
I use twin sensors mounted on the inlet manifold. I use a KnockTek from MS2 Tuning http://www.ms2tuning.com/products.html with a megasquirt ECU.
N7GTX said:
WowSomeone is really showing off...
Got any details on the knock sensors used?
Cheers
MPO
BoostedChim said:
I use twin sensors mounted on the inlet manifold. I use a KnockTek from MS2 Tuning http://www.ms2tuning.com/products.html with a megasquirt ECU.
Nice..., are you using the knock sensors that are referred to in the knocktek info or others?Any issues, many false negatives?
Cheers
MPO
Hoofa said:
Use the Bosch motorsport ks-p sensors, rather cheap and fit on the block either side using the predrilled knock sensing holes, assuming your back has them of course
Thanks Nigel. Impressive figures on your Chim 
Sadly, no pre drilled holes on my current block.
Are you aware of them being used successfully in other locations on a Pre Serp?
Cheers
MPO
MPO said:
Nice..., are you using the knock sensors that are referred to in the knocktek info or others?
Any issues, many false negatives?
I use these http://www.ebay.co.uk/itm/RANGE-ROVER-P38-ENGINE-K... they are the sensors fitted to the later range rover blocks. They should be mounted as Nigel says on the sides of the block, but mine doesn't have the bosses to mount them.Any issues, many false negatives?
No issues, the only false readings I get are on the rev limiter, it doesn't like the spark cut.
Hoofa said:
No I don't , what I do know is knock is something that has to be set very precise, plus you need to know and have experience of it , the standard knock positions on the block work well , as I am running sequential injection the car knows which cyclinder is firing and pulls the ignition on that cylinder, you don't mention what ecu you are using, who is setting up your knock ?
Hi NigelThanks, my other block has provision but that is still being built but I want to run something on my Pre Serp for now…
Basically, I’m looking to collect real-time data output from a knock sensor and correlate it with the 14CUX and 123 Ignition Tune data that I already collect and correlate for my DIY mapping.
I will not be looking to adjust ignition advance on the fly (real time). I’ll be looking for exception data (knock instances) whilst I am creating a safe ignition advance curve during my DIY tuning.
Its early days, but I’m quite keen to identify a knock sensor that works with the RV8, hence my questions and I appreciate the replies.
Out of interest, would you know what voltage output ranges you are seeing from your knock sensor(s) when experiencing unacceptable knock levels?
Cheers
MPO
BoostedChim said:
I use these http://www.ebay.co.uk/itm/RANGE-ROVER-P38-ENGINE-K... they are the sensors fitted to the later range rover blocks. They should be mounted as Nigel says on the sides of the block, but mine doesn't have the bosses to mount them.
No issues, the only false readings I get are on the rev limiter, it doesn't like the spark cut.
Where are you mounting them?No issues, the only false readings I get are on the rev limiter, it doesn't like the spark cut.
MPO
Knock sensors are just microphones, but are mechanically tuned to pick up the specific knock frequency of your engine, and This will vary depending on combustion chamber size so ideally you should at least try and get a pair of Rangerover P38 ones to be somewhere near correct. The rest of it is down to some fancy filtering electronics to try and pull the specific knock frequencies (typically around 7.5kz) out of the mechanical clatter the engine produces. If you are using aftermarket knock electronics , then you can simply wire the knock sensors up on the bench to the unit, then hit them with a spanner and see if you get a reading. Least that proves its working. Personally Ive tried wired in knock sensors to an audio amp with headphones to try and listen for it, after all the human brain has a pretty good audio filter in the shape of a pair of ears, but Ive NEVER managed to actually get my engine to knock, or a friends 5ltr TVR. The Extra EFI knock detector never gave me a reading as well, even though it worked on the bench. I did run this past Mark Adams who said its very difficult to get the RV8 to knock unless its running lean as well, and knock occurs well after peak torque has been passed, so its not a good benchmark for setting your timing anyway. I reluctantly gave up on my 3.9 preserp engine as I was worried Id damage it if I pushed the timing too far just to prove knock detection worked. Im sure it can be made to work as the GEMS ECU uses it, but for us who like to experiment it could be an expensive mistake if you dont pick up knock when its happening.
blitzracing said:
Knock sensors are just microphones, but are mechanically tuned to pick up the specific knock frequency of your engine, and This will vary depending on combustion chamber size so ideally you should at least try and get a pair of Rangerover P38 ones to be somewhere near correct. The rest of it is down to some fancy filtering electronics to try and pull the specific knock frequencies (typically around 7.5kz) out of the mechanical clatter the engine produces. If you are using aftermarket knock electronics , then you can simply wire the knock sensors up on the bench to the unit, then hit them with a spanner and see if you get a reading. Least that proves its working. Personally Ive tried wired in knock sensors to an audio amp with headphones to try and listen for it, after all the human brain has a pretty good audio filter in the shape of a pair of ears, but Ive NEVER managed to actually get my engine to knock, or a friends 5ltr TVR. The Extra EFI knock detector never gave me a reading as well, even though it worked on the bench. I did run this past Mark Adams who said its very difficult to get the RV8 to knock unless its running lean as well, and knock occurs well after peak torque has been passed, so its not a good benchmark for setting your timing anyway. I reluctantly gave up on my 3.9 preserp engine as I was worried Id damage it if I pushed the timing too far just to prove knock detection worked. Im sure it can be made to work as the GEMS ECU uses it, but for us who like to experiment it could be an expensive mistake if you dont pick up knock when its happening.
Hi MarkThanks for your reply and pointers it’s appreciated
It’s just an experiment as you say but as I’m always logging data I thought it would be best to give it ago, got plenty of time on my hands at the moment.
If you recall, I used to get pinking when using 95 RON and my Standard 1992 TVR/RR Dizzy was set at 14Degrees BTDC and Vacuum attached. I could only run it on 98 RON. We put this down to High Compression.
Based on my research, the standard vacuum advance of 16 Degrees BTDC on light to medium throttle coupled with all in static of 32 Degrees BTDC at 3500 could have given me a high at 48 Degrees BTDC at almost 50% throttle and didn’t it pink! Using 95 RON!
However, that was before I mapped the car from its standard tune, so it could have been lean too. I’ve moved on since then but still avoid 95 RON…
Cheers
MPO
Edited by MPO on Sunday 14th August 21:01
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