Zuki1216
Extreme
- Joined
- Dec 9, 2015
- Messages
- 93
- Age
- 51
- Location
- Indiana
- Country
- USA
- Snowmobile
- 08' Apex LTX
07' Attak MPI S/C
07 Attak w/ MPI stage 1. Bought sled used. No shim. He was running 10-12 pulleys w/ 50/50 mix. Old gems controller. Sled starts and runs great. But I want to switch to a PCV setup and would also like to add a knock sensor so I can maximize boost w/ pump gas. Mainly trail ridden. What I've read is 5lbs max with no shim. But I'm thinking with the PCV and knock sensor I can squeeze more out of it.(don't really want to shim, seems counterproductive) I've seen old post about the Parker Motorsports knock box, but it looks like they are out of business. So any alternative?
Stigapex
Suspended
Put in a shim, mcx kit runs 14-15 psi with shim. Add a pcv ignition controller, and add some timing in lower rpm. I use a garrett 3071, with thicker headgasket and lowcomp, and added some degrees timing in lower rpm. Very fast from start
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kinger
VIP Member
Sorry unless the knock sensor is $1500 motec calibrated to the apex they won't work. Also shimming is not counterproductive especially on a sc machine when your generating 5 psi at clutch engagement. You can try but your playing with fire. 10-11 psi SC shimmed to 10:1 is a proven reliable 240-250hp just turn key and ride.
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nate007
Lifetime Member
- Joined
- Dec 25, 2006
- Messages
- 2,770
- Location
- Iowa City, Iowa
- Country
- USA
- Snowmobile
- 1. '06 Apex -twin screw
2. '04 Redline Revolt 800
3. '09 Nytro XTX - twin screw
To elaborate in what Kinger posted, knock sensors are a very finicky process to perfect, and each sensor much be tuned for each engines harmonics and "nose".
I know of one member (1CrazySledder)that had a Parker box on his sled, and he's said that the light would flicker and flash quite a bit at all times unless he adjusted it down to desensitize it enough that it was basically off.
To get one to actually work properly, you'd have to basically dyno the engine in various conditions with various grades of fuel and know 100% that it is NOT knocking. Then you'd have to continue assisting fuel quality, timing and AFR to get it to knock and calibrate the sensor to recognize the difference. Literally too scientific of a process without equipment that only OEM's can afford.
The way they combat knock is to run the engines with a bit more conservative timing and slightly richer AFR's.
There's plenty of threads here about tuning with boost so I won't get into that here, or tell you what you should do. Sorry to rain on your parade, but the knock sensor issue is one that can't feasibly or reliably be solved on a sled in the aftermarket.
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I know of one member (1CrazySledder)that had a Parker box on his sled, and he's said that the light would flicker and flash quite a bit at all times unless he adjusted it down to desensitize it enough that it was basically off.
To get one to actually work properly, you'd have to basically dyno the engine in various conditions with various grades of fuel and know 100% that it is NOT knocking. Then you'd have to continue assisting fuel quality, timing and AFR to get it to knock and calibrate the sensor to recognize the difference. Literally too scientific of a process without equipment that only OEM's can afford.
The way they combat knock is to run the engines with a bit more conservative timing and slightly richer AFR's.
There's plenty of threads here about tuning with boost so I won't get into that here, or tell you what you should do. Sorry to rain on your parade, but the knock sensor issue is one that can't feasibly or reliably be solved on a sled in the aftermarket.
Sent from my SM-N910R4 using Tapatalk