Is the knock sensor playing with me, Apex 2011

[Stigapex]

Hello

I have a 2011 Apex, with MCX 290, running at 16-17 psi, at premium fuel.
When I hold the throttle open for 8 to 10 seconds something is working against the sled. I can't see at the RPM-gauge in that speed, so I don't know if it's falling, but something is working against the sled. First I thought it was something with the track or clutches, but I can't find anything wrong with that. When driving in 3/4 throttle open ,around 100 MPH, nothing wrong. But if I then hit full throttle, after 8-10 seconds something happens. Also if I hit full throttle from zero, after 8-10 seconds somethings wrong. The 2011 Apex have a knock sensor, could it be the knock sensor, that is detecting detonation? How will that feel? I can't see any warning light

 

[DooAssassin]

You are playing with fire running 17psi on pump gas. You will not feel or hear detonaton it just happens. After a few times something will give. Don't run 17 on pump run 14 Max. Also if the knock sensor kicks on the rpms will not be as high during, untill the knock sensor senses no knock then it will go back to normal.
I am telling you don't run 17 on pump, I accedentally ran 17-20 because my boost guage wasint working correctly and ovaled my cylinders. Good luck

 

[DooAssassin]

Run race fuel at 17 psi and see if it still does it. I have a good feeling you won't have that problem anymore

 

[Riceburner]

I agree with all Dooassasin wrote.

Don't go over 14 lbs on pump gas.

It is very likely the knock sensor. It retards the timing which will pull power from the engine.

Probably that is what you are feeling.

 

[TBird]

x3, the kit is designed to run 14psi - 290hp.
Running 17psi on pumpfuel is playing with fire.
Turn it down to 14psi to verify that it runs perfect on that level.
Running more then 14psi can work from day to day depending on fuel quality, but it can also say kaboom!!! not so fun, it's alot nicer to run 14psi and avoid problem, 290hp is plenty fun! .

 

[nate007]

The fuel thing is the first thing, as everyone else said, RUN RACE FUEL. Also, it may not be the case, but what are your AFR's when this anomaly happens? This could be a reach, but if you're running the stock fuel system you could be starving it, as a lag after a certain time on boost could be consuming more fuel than the stock pump/regulator, etc can deliver?
Try race fuel first, if that doesn't do it, watch your AFR's closely, and add a fuel pressure gauge. If the fuel pressure drops at the time it starts "dragging", you're not getting enough fuel.

 

[Stigapex]

Sorry, I'm a little late to answer, but have som problems logging in.

I have tried it running at 14psi, the same problem, but it seems that I could hold full throttle a little longer,maybe 15 seconds.
It's not so easy to get hold of race fuel around where I live, and it's extremely expensive.(Everything is expensive in Norway)
Is there anyone that sells racefuel in Northern Sweden to an ok price. I use to spend some time in Piteå in Sweden,
so if there is someone around there who has racefuel, let me know.
I don't have a AFR gauge, but will add the MCX unit to the sled next week, to see if it's running lean at top.

I was reading the MCX dyno for the 290 kit, and it says 105 kpa and thats 15,2 psi.

 

[TBird]

Yes, the graph shows ~105kpa, but Erik writes "With lower compression, turbo pressure is set to about 100 kPa. (14 psi) The power is about 290 hp."

You really need the AFR gauge, and with the display you also get logging which is perfect,,
Running 14-15psi on our premium is one thing, it's scary enough, but running 16-17psi on premium is really scary, especially during so long pulls as you do. If you plan to continue to run 16-17psi i would look in to meth, especially with our crazy prices on race fuel!

 

[Stigapex]

Yes, the graph shows ~105kpa, but Erik writes "With lower compression, turbo pressure is set to about 100 kPa. (14 psi) The power is about 290 hp."

You really need the AFR gauge, and with the display you also get logging which is perfect,,
Running 14-15psi on our premium is one thing, it's scary enough, but running 16-17psi on premium is really scary, especially during so long pulls as you do. If you plan to continue to run 16-17psi i would look in to meth, especially with our crazy prices on race fuel!

Not usually doing long pulls, but had to try, when the conditions got perfect.
I thought of adding meth and launch this autumn.
We usually only do 660ft pulls, but I have problems hanging up with the 270MCX Nytro.

Do you know someone selling racefuel in Northern Sweden. Usually it's a little cheaper in Sweden then in Norway.
Price in Norway 50NOK/liter = 57SEK/liter = 33USD/gallon

 

[TBird]

Well, since i have no trouble beating Nytro270 there must be some issue with your setup.
A good running setup don't come easy, there are many hours of tuning, nad with the MCX display you get a really good tuning aid.

The only ones i know that can have race fuel up here are MCX, Tikka Racing, PF Racing but they don't sell fuel so they sell if they have anything @ home.
Best bet to get race fuel up here are http://g-son.hube.se/index.php?page=ag&info=ag
Storumans Skoterskrot have sold VP, don't know if they do anymore http://www.skoterskrot.se
I know Race shop have fuel but it's in south http://www.race-shop.com/ShowSearchResu ... hstring=vp racing