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734RStreetScraper
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358 Posts
Discussion Starter · #1 · (Edited)
just wondering how you guys contol engine knocking.
especially the high hp and boosted monsters here.
i mean when you go above a certain compression wich turbo,s love to do you got to control the timing to prevent knocking but highspeed knocking is very hard to notice.
how do you guys check this? is it noticable on a dyno or what?
 

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From The Stix 2 Da Brix
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11,616 Posts
Higher octane fuels help prevent knocking.
 

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191 Posts
I don't know if water injection has been used on boosted raptor engines.
But this technology works I use it on my boosted mazda rotary and run the nozzle pre turbo and I only run water not a water methanol mix.
It cleans the engine and prevents detonation.
here is a link for some info. http://www.riceracing.com.au/water-injection.htm
If this was set up properly on a 700 raptor motor the results would be worth the trouble.
 

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734RStreetScraper
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358 Posts
Discussion Starter · #4 · (Edited)
Higher octane fuels help prevent knocking.
i know,you have lots of ways to prevent knocking,like higher octane/retard ingition/lower compression etc. but you want to be as close to knocking point as can be for max. power output, but when do you know you hit the turning point where the engine starts to knock.
this is important because the 1cil. makes that much noise at high rpm that i think it,s hardly noticable.
the reason i ask is i am a bit experimenting with the dyna ignition and i want to know how far i can go without damaging the engine.
 

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If I was running a boosted engine on my raptor I would rather have the reassurance of water injection instead of running funny money fuels.
You can run massive boost without funny money fuels.
I have experienced first hand what a bad batch of e85 can do to a highly tuned motor.:mad:
I would rather run premium pump gas and get the better results with water injection.
 

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Super Moderator
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Right now, by running the appropriate octane level for the compression encountered, or alcohol/methanol/other fuels. Water injection is few and far between.

How far you can go with the timing is dependent on the fuel you plan to run and the compression in the engine and the grind of the cam. If you want to devise some sort of anti-knock loop in the computer (there is no such procedure in the OEM ecu to my knowledge) then feel free, but assuming you were to get such a loop working properly I don't feel that cranking the timing to the moon and then relying on a second system to prevent damage or just running poorly would be the best choice.

It sounds to me like you have a lot of time ahead of you on a dyno adjusting timing curves. As far as procedures to prevent knock in this scenario I am not clear, one could run the desired octane and attempt to detect pinging/knock or run a higher than desired octane to prevent any and then hope it doesn't do so when you find the curve you want.
 

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I am unique
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22,621 Posts
Some snowmobile CDIs have the technology to detect knocking, the sensor is situated on the head............
It allows only very minimal knocking and the timing then gets retarded................
 

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734RStreetScraper
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358 Posts
Discussion Starter · #8 ·
did some simple recearch on internet but they say that knockingsensors don,t work well on 1cil engines because the engines make to much "noise" for the sensor to detect knock.
 

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8SEVENTY3
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1,336 Posts
Theres plenty of people that have those dynateks figurerd out....Lucas English knows where to set the timing and DL700 knows what hes doing too. You could probably contact either of them and find out anything you need to know.
 

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734RStreetScraper
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358 Posts
Discussion Starter · #10 ·
tnx. for me it,s just a learning process. but timing is not to be taken lightly as i could damage the engine severely due to detonation.
 
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