Where's my boost hiding? (MPI S/C)

[A.Granath]

I only get about 3psi of boost @8000rpm (2000ft), can you guys give me some advice where to start searching?

Specs:
Nytro 2009 xtx. 2" lugs
Brand new Rotrex charger from mpi with 28/28 pulleys
Headshim
Intercooler
MCX gen5 box with 3 extra injectors
AFR reads steady 12.6 @8000rpm

I appreciate all help i can get!

//A.Granath

 

[stingray719]

Exact same thing happened to my MPI S/C Phazer. Check your pullies, mine slipped and did that same thing for almost 100 miles before the pulley blew clear off. Please note the pullies have to be installed in a certain way, call Matt at MPI and I am sure he will help you.

 

[Matt@MPI]

What pulleys do you have?

 

[A.Granath]

What pulleys do you have?

I have 28 top and 28 bottom.

I can't see how the pulley or belt can slip without being mechanically damaged?

 

[stingray719]

I have 28 top and 28 bottom.

I can't see how the pulley or belt can slip without being mechanically damaged?

I thought the same, but it did slip for about 100 miles before it blew. Check the pully design, its not a normal pully it has a center and outer.

 

[Matt@MPI]

I only get about 3psi of boost @8000rpm (2000ft), can you guys give me some advice where to start searching?

Specs:
Nytro 2009 xtx. 2" lugs
Brand new Rotrex charger from mpi with 28/28 pulleys
Headshim
Intercooler
MCX gen5 box with 3 extra injectors
AFR reads steady 12.6 @8000rpm

I appreciate all help i can get!

//A.Granath

I don't think those pulleys with the headshim and only 8000 RPM will make more than 3 psi. Those pulleys and 8800rpm with NO headshim @ 2000ft should make 6-7 PSI. I think the headshim is loosing about 2-3 and your low RPM is to blame on the other 1psi

 

[A.Granath]

I don't think those pulleys with the headshim and only 8000 RPM will make more than 3 psi. Those pulleys and 8800rpm with NO headshim @ 2000ft should make 6-7 PSI. I think the headshim is loosing about 2-3 and your low RPM is to blame on the other 1psi

Thank's Matt for your help!

I hope that this week my 31/23 pulley combo will arrive, after that i will try to get the rpm dialed in on 8800!

As for now i'm testing the 8HG-00 weights and a 43 degree helix. Before that i had STM 60Y weights but i felt that the supertip where to aggressive in the start and it was hard reach top rpm.

 

[A.Granath]

Finally i got my 23 / 31 pulley combo up and running. I still have a issue that i don't get the belt tight enough even if i bottomed the tensioner wheel. Maybe Matt@MPI can give some advice on that one?

Here is a reading from my first pull, track is just lifted from the floor... i have no snow here by the coast to do some real tests

MAP = 187.92 = 12.75 PSI @ sea level

 

[Matt@MPI]

I think that’s a lot of boost for a stage one with a head shim! Nice work! You might need a longer bolt in your tensioner. We have two different sizes to use based on what pulley combo you have. Send me a picture and I'll take a look.<O</O

 

[A.Granath]

I think that’s a lot of boost for a stage one with a head shim! Nice work! You might need a longer bolt in your tensioner. We have two different sizes to use based on what pulley combo you have. Send me a picture and I'll take a look.<O</O

Do you have different diameters on the tensioner wheel depending on pulleys? I have the adjustment bottomed out but it feels like i need 5-10 millimeters more to get the right tension.