More MPI Turbo Questions

sled obsessed · Feb 10, 2013

I've been trying to get my MPI 180 kit dialed in for riding low elevation. Think I am getting close with the clutching but wondering about getting the boost pressure up. Out of the box was only around ~3lbs. I have turned the rod on the waste gate ~6 revolutions (which according to the instructions should get me an additional ~4lbs). Last weekend on step up snow its was hitting 5-6lbs. Took it out yesterday and would only hit 4lbs in fluffy snow. My Question is if the engine was under more load in the set up snow will it build more boost pressure? Should I keep turning the waste gate closed a couple more revolutions (concerned that if I crank it up then in certain conditions will go a little too high)?
Even when it was only making 4lbs in the fluff it was still hitting 9k on the tach.

TABSTER · Feb 10, 2013

all the kits i install including mine run at 5 to 6 lbs at our elevation on pump gas. some boost gauges are out to lunch, they all read alittle differant. You sure that your blow off valve is closed once you build more than 4 or 5 lbs boost? 9 grand is to high for rpm. feel free to call me and will dial it in for you. i set them up to run at 8300 to 8500rpm

sled obsessed · Feb 10, 2013

not sure the BOV is not opening up above 5lbs. Would a guy hear that? Thought all kits ship with a 10lb spring in the BOV. So if you run 5-6lbs in stoon do you have that switch installed for when you go the the mountains to increase to 7-8lbs?

TABSTER · Feb 10, 2013

sled obsessed said:
not sure the BOV is not opening up above 5lbs. Would a guy hear that? Thought all kits ship with a 10lb spring in the BOV. So if you run 5-6lbs in stoon do you have that switch installed for when you go the the mountains to increase to 7-8lbs?

You will hear if its open. I do run the air switch with a 155 carb jet, and yes I run 8 lbs at elevation with 11.2 to 11.6 on A/F. If your banging the rev limiter you need to do some clutching. Also make sure belt is in good condition.
I recommend green white green primary spring, 14.5 mm rollers. I run dalton dtya-2 weights set at 80.3 grams, stock weights will work with all three holes loaded with solid steel 17.2 gr. In the secondary a white yamaha secondary spring and stock helix in position 1 and 6, 1+6=7x10= 70 degrees. This will give you 8500 rpm +/- 50 rpm. This works well...

sled obsessed · Feb 11, 2013

thanks for the info tabster, i am actually running a similar clutch setup (stk weights loaded up, same springs and rollers with a yam 41 deg helix). and at 4psi was hitting 9K on a long pull through fluffy powder. Mine is a 153, you think it needs to be clutched a little different than a 162? I had an autometer gauge on it then switched to an aem digital and they both are basically always showing ~4lbs. At times I could bounce 5-6 but it was only for a second and then back down to 4. Think I will just try to turn the boost up a little more. May twist my secondary to 80 or 90 deg first to see if that will bring the rpm down a couple hundred (although I hear thats not the best way to run yam springs). was also thinking about trying a 43 deg helix for our elevation.
Appreciate the info i am kind of a noob in the wrenching department

TABSTER · Feb 11, 2013

sled obsessed said:
thanks for the info tabster, i am actually running a similar clutch setup (stk weights loaded up, same springs and rollers with a yam 41 deg helix). and at 4psi was hitting 9K on a long pull through fluffy powder. Mine is a 153, you think it needs to be clutched a little different than a 162? I had an autometer gauge on it then switched to an aem digital and they both are basically always showing ~4lbs. At times I could bounce 5-6 but it was only for a second and then back down to 4. Think I will just try to turn the boost up a little more. May twist my secondary to 80 or 90 deg first to see if that will bring the rpm down a couple hundred (although I hear thats not the best way to run yam springs). was also thinking about trying a 43 deg helix for our elevation.
Appreciate the info i am kind of a noob in the wrenching department

Look at your primary clutch face, where is the belt running? All the way to the top of the primary? If you are unsure the mark a chalk line on the clutch face and go for a poke. I have a couple Mpi's dialed in already I will measure the waste gate push rod length so you have a ball park idea where to be. Don't recommend more twist than 70 deg. I have tried 8FS weights and 8FP loaded up but found Dalton's to work the best, pricey but so easy to adjust and work awesome. Easy peasy to tune.

sled obsessed · Feb 12, 2013

I would be interested to hear the measurement on the waste gate push rod. would be nice to know that I am not turning it too much.

TABSTER · Feb 12, 2013

sled obsessed said:
I would be interested to hear the measurement on the waste gate push rod. would be nice to know that I am not turning it too much.

Okay, I will measure them tonight. I think you need to throw more weight at the primary for home. Your stock weights will do in the alpine but little to light for us here.

sled obsessed · Feb 12, 2013

Sounds good man thanks, I think you are right about the primary weights, gonna mess around with a 43 and 45 deg helix on sat to see what that does and go from there. Like you say I likely more weight on the primary for around here.

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