Mcx270 burp for the intake at low rpm

[Martens199]

Hey guys,
Riding out in revy today testing out my new SRViper with the mcx 270 turbo. Noticing that between 3000-4000 rpm when throttle held at a constant speed. I get a burp or backfire coming out of the intake on the turbo. It does it intermittently throughout the day. Not backfiring out the exhaust.

 

[Armani]

Hey guys,
Riding out in revy today testing out my new SRViper with the mcx 270 turbo. Noticing that between 3000-4000 rpm when throttle held at a constant speed. I get a burp or backfire coming out of the intake on the turbo. It does it intermittently throughout the day. Not backfiring out the exhaust.

Have the same on mine, MCX is working with a new map to eliminate that,, but give the sled some miles, and the burping reduces

 

[Jabakanada]

My friend had same? problem with his 270MCX Viper or he saw lean conditions before boost. He relocated the intake temp sensor between the air cone and the turbo (He has pulled the air cone outside the hood, cold air intake). Problem was solved. He is seeing now no higher AFR than 14,5 in any given rpm and of course a lot lower at WOT. This is against the instructions from MCX kit installation but now the sled is running good. If you wanna try this I suggest that you have proper AFR gauge or nerves cold as steel when you make long WOT pull

As far as I am concerned MCX designed this kit by using pre-manufactured test drive/expo snowmobiles which had different fuel maps or ECU software. That's why you get additional A4 paper with normal installation instructions for pressurizing the barometric sensor from MCX IC/plenum.

 

[Martens199]

Yeah mine is snorkelled out the hood as well, this is really when I noticed the coughs from the filter. I also have hear they are coming out with some new programming, I don't have and afr gauges so I better wait for the update!

 

[Jabakanada]

I have noticed that other kits have located that intake temp sensor to intake hose before turbo. MCX tells you to tie it up to wire harness near clutch.

And as I understand how this machine is running it only gets richer AF ratio after this modificafion.

 

[Martens199]

Ok yeah mine has been tied up against the frame. Which kits have you seen it in the intake hose? Any high altitude kits did you do that to your sled as well?

 

[Jabakanada]

http://www.ty4stroke.com/threads/turbo-install-help-needed.133112/ that link goes to Viper topic and MPI kit installations. There is couple pics about that sensor location. I have different ecu software than stock and mine works well with temp sensor located like MCX instructions says. I might still do that sensor relocation because I pulled my air cone outside and I guess it will be problem when we get dream pow after 1-2 months and underhood temps gets higher and higher. It's easy to make hole to silicon hose and ziptie that sensor to the hose before turbo. If it makes engine running richer before the MCX efi-box kicks in and solves the problem then I guess it's worth of trying.