MCXpress help needed

Hey guys,

I'm still having an issue with my MCXpress Apex having major turbo flutter. I have the 290 kit with the 19T Turbo in it. Currently I'm running 17lbs of boost and it runs great, except when I let off the throttle. My blow off valve on the intercooler will not lift, and I get turbo flutter coming out the back. One thing I did notice is that when i pulled the tube off the blowoff valve while the sled is running, it doesn't even really do anything. it doesn't even drop in RPM or anything. I do feel a little bit of vac, but hardly anything, my boost guage isn't showing much vac either at idle, but still shows full boost when I'm hard on the throttle.

Having a look at the way the lines to the boost gauge, and the blowoff valve are routed, they are connected to the cylinder closest to the brake, and then there is a line running to the cylinder closest to the belt.

On the cylinders, they are hooked up to the top vac port. One thing that I did notice is that the line hooked up to the vac port on the brake side slid off no problem when I went to disconnect it. It didn't take much at all to pull it off. The other side where the belt is, I couldn't even get it off.

Could this be where my vac leak is? I haven't tried running the sled with the port plugged yet, cause it's late, but I'd like to get his fixed.. I seen an apex in the mountains with the same kit, except the blowoff valve was on the charge pipe, not too sure how the lines were routed though, and it worked perfectly.

Any info would be great. Thanks.

Hey Sly,

I did have a look yesterday and proved all the lines kink free. I also blew some compressed air through them to ensure there was no blockage, plus I put them in the house to ensure there was no ice in them.

Any other ideas?

I forgot to mention, I have put a different BOV on it, to try to figure it out. I put a turbosmart veeport on it. And it is at the lightest setting. When I push on the piston to lift it, it hardly takes any pressure...I'm thinking it is a vac issue. I'll let you guys know what I find out tonight...


Thanks guys..

Thanks for the suggestions guys. The one port that I had suspected, the tube comes up while in boost and then when i let off, the tube is about half way up the vacuum port and probably eventually slides down. I'm going to try glueing this and see what happens. Yesterday I plugged off the brake side port and just utilized the belt side port to see what type of vac I was pulling with my boost gauge and i was showing -5lbs at idle.

If this doesn't work I'm going to try another source. There is another tube right below the vac port (a grey tube) on the brake side that feeds to a sensor right in front of the throttle body. Would you guys recommend utilizing this one?

Also, I still do have the MHI BOV, so i could put the Veeport on the charge pipe if the vac relocation doesn't work... I'll update you guys on Friday or Sat.