Boost spike question

[smoothdawg]

I am running an OVS pg Aero kit on an 09 M1000 at 7 lbs. I have an adjustable boost controller with no BOV. Is it normal to see a boost spike when you chop the throttle? I have seen what appeared to be as high as 10 lbs. of boost when I chopped the throttle. I am worried that on a long hard pull when I let off it will spike and squeak the motor. I never noticed this prior to installing the boost controller. I was also only running 4 lbs. of boost then. There is no run on when I let off the throttle, didn't know if that was pertinnent or not. Should I be checking something?

 

[Wheel House Motorsports]

yes, you will get an instant spike up right when you chop the thing.

dont worry about it, none of that pressure is seeing your motor, theres a spike because theres a ton of air stackin up against the throttle plates and creating a pressure spike. if you have your gauge plumbed into behind the throttle bodies it will drop instantly into vaccum, but I bet yours is into the airbox.

 

[RACINSTATION]

I would get rid of the boost controller and set your boost with the wastegate arm. The controllers always cause spikes.

 

[snwman77]

Now im sure it depends on what boost controller you have but they may all have a check ball on the inlet side of the controller, the inlet side would be the side away from the waste gate controller. But what im saying is, If you can unscrew the inlet fiting from the controller, a small check ball and a spring should fall out. Take them both out, that will help with boost spike.

 

[smoothdawg]

All of my boost reference points come from the air box.

Not sure what the brand name of the controller is. Bought it from OVS.

If you take the adjustment knob apart there is a plastic ball and spring under there. How would removing these prevent boost spike? Sorry I am still a rookie to some of this.

Is the boost spike something to worry about? Ski-dooin it says no and Racinstation implies yes. Which is it? I am afraid of seizing the motor. Thanks.

 

[Coxy]

When the throttle plates snap shut, the motor goes right to what little vacuum it makes, the turbo is still moving alot of air, so inturn you build pressure up between the compressor wheel and throttle plates, your reading boost at the airbox, which is in the spike area. If you were getting your boost source for your gauge at the motor side of the throttle plates your not seeing anything dangerous there. The turbo may not like it, but your not likely to do damage to the motor.

 

[shawkins]

This is normal for an Aerocharger. One of the advantages of the Aerocharger is it has a soft surge line. Meaning you do not need a blow off valve to keep from damaging the compressor section. Also OVS uses a BLOX boost controller.

 

[smoothdawg]

Thank You all for the info. It seems logical as explained above, that the air is just stacking up in the air box causing the gauge to register the higher boost for a moment.

Just curious. How would removing the check ball and spring alleviate the spike in pressure?

 

[RideGuy]

I had a loose secondary last year and the boost was fluctuating..... It did resemble a boost spike.... F.W.I.W.

 

[Aerocharger_Brad]

Adjustable boost controllers are very handy but can cause the type of issue. Give me a call and I can get you the parts you need. There is also a video on YouTube you should watch. http://www.youtube.com/watch?v=glskvHdukiQ You can also Open the vanes to help with this. All in all you will not hurt anything.

 

[shadow conspiracy]

smoothdawg are you running dual injectors? I have the same kit and am only making 4lbs of boost as well and want to turn it up. Im not very impressed with my sled the way it is now. A 2010 stock m8 keeps up to me no problem.
I think i need to throw more weight in the primary even though my rpms are at 7450. I have my adjustables maxed out at 87grams but it seemed to pull the same rpms everytime i added weight to them. Was told to run 92 grams? Sled also likes to trench real bad and need to figure something out for that.

 

[Aerocharger_Brad]

smoothdawg are you running dual injectors? I have the same kit and am only making 4lbs of boost as well and want to turn it up. Im not very impressed with my sled the way it is now. A 2010 stock m8 keeps up to me no problem.
I think i need to throw more weight in the primary even though my rpms are at 7450. I have my adjustables maxed out at 87grams but it seemed to pull the same rpms everytime i added weight to them. Was told to run 92 grams? Sled also likes to trench real bad and need to figure something out for that.

Call OVS and get some help. Sounds like a few things need to be adjusted. They are good at helping you. Feel free to call me as well.

 

[shadow conspiracy]

Sled runs good just not making the power i thought it would(should) Its not much better than stock. Besides clutching and adding boost i cant really see what can be adjusted. I will be calling as i want to order a couple shims. I am running straight AV fuel, maybe thats part of the problem. Dont really need that fuel for 4lbs i think.