Installation & Review: Yamaha OEM Turbo & MPI Stage One Upgrade

[tmk50]

I find very little to no lag on my MPI kit. Keep the RPMs up and don't free wheel it like a two stroke. I have been on 4 strokes for since the 2002-2003 season. I quit letting all the way out of the throttle very early on - the first yamaha 4 strokes had a lot of engine brake, so I didn't have much choice I guess....

 

[christopher]

Certainly an acquired skill of NOT letting the engine slow back down to idle


Sent from my iPad using Tapatalk 2 pro.

 

[BigFish BC]

Now as for the report on the ride that we took yesterday it was overall a pretty good ride.

I believe the largest thing that I learned from this trip was turbo lag. Now when I would be riding at really slow speed be it on the trail or in powder and I would grab a handful of throttle. The sled would make about three bogging sounds and lose power and thing hit me with full power.

Now I thought with a turbo that I would not lose power when I hit the gas but just the additional "turbo" power would come a few seconds later.

This led me to be carving in the snow and I would go to pull a hard turn in the snow and lean into it and then grab the throttle to power out of it and the sled would bog for a second or two and the sled would end up falling over.

From what everyone has been telling me, I need to be brapping the engine more to keep the turbo spooled up so its ready for when I need that instant power.

sounds like something is still off all rear mount turbos have a hesitation but not measured in seconds.sounds like you have a fueling bog ,to rich to lean.on rear mounts clutching the sled for a 4000rpm engagement will help allot too.

 

[adairtd1]

I also get pretty much zero lag on my mpi kit.

 

[Powder Man]

My push kit has no noticeable turbo lag too. I agree about your fueling being off. I would pay close attention to what your gems box is doing when you have the hesitation and try to adjust it out. The dobeck style fuel controller is a pain and why I went to the bridge from physcosled, no more pushing buttons trying to tune out those flat spots.

 

[christopher]

No doubt the turbo is NOT "dialed in" yet.
But I also had a chance to ride his sled a bit on Saturday out in some open meadows.

Now, understand, I ride almost 100% on a Supercharged Nytro, so my power-response expectations are VERY different from the average Turbro rider. With that in mind..

I would be riding through an open meadow with 1foot of fresh on it.
Would roll into a nice turn, hit the gas and keep right on rolling over, fear I was going to biff it and then WOOSH the turbo would hit and the sled launch and it was all I could do to hold on for the ride as the sled powered through the turn and righted itself again.

For "ME" there was a huge lag. Maybe a full second or so, but it seemed like an eternity for a guy used to a supercharger with INSTANT throttle response.

His sled was FASTER than mine, hands down, but mine was QUICKER every time.

In the open the turbo was a "BLAST".
In the tight the supercharger RULED.

Small precised applications of power were easy with the supercharger, and took much more "Skill" or concentration with the turbo.

Both the Turbo and the Supercharger require some very specific thumb technique and for the most part they are just the opposite of each other.

 

[2Huskies]

My push kit has no noticeable turbo lag too. I agree about your fueling being off. I would pay close attention to what your gems box is doing when you have the hesitation and try to adjust it out. The dobeck style fuel controller is a pain and why I went to the bridge from physcosled, no more pushing buttons trying to tune out those flat spots.

I guess the next step for me is to learn how to use the Gems Box. Ill be honest, I do not know how to use the buttons on it.

But I have faith that Matt@MPI will hop in here and help out. Or Powder Man if you want to tell me how you did it.

 

[Matt@MPI]

I hit 95 miles an hour and the top rpm I saw was 9380 to be precise.

What's your secondary clutch set up like?

 

[2Huskies]

That would be however it was set when we purchased the sleds.

 

[Powder Man]

To tune with the gems box you need an air fuel gauge, I run an aem digital. Watch the gauge when you have the hesitation/bog, the lights on the gems box will be lit the color in which mode it is fueling red green or blue. Adjust each mode according to what your gauge reads rich or lean.

It takes a little time for proper tuning and you'll have to continually make minor adjustments based on elevation but you should be able to tune most of your problem out. The constant adjustment and trying to get it tuned perfect is why I went to physcosled's bridge controller this year. I haven't gotten on the snow yet so I can't comment on the performance yet, but it should run much better.

You may need to adjust your secondary as well, can't remember what mine was at low boost. I'm different than you as I'm running more boost. I have stock rollers fully loaded stock arms and a shock wave in my secondary, forgot about springs and what the secondary is wrapped too I'll have to look.

 

[Matt@MPI]

That would be however it was set when we purchased the sleds.

Was the sled brand new?

 

[2Huskies]

Yes off the show floor Matt

 

[2Huskies]

Powder, what do you mean when you say shock wave in the secondary?

I understand the fully loaded arms but, nothing really in the secondary.

 

[judger101]

the shockwave is an adjustable helix on the secondary. it allows you to change the ramp angle of the helix. while not the best way to adjust rpms you can fine tune your rpms by changing the shockwave helix angle.

 

[Powder Man]

Yes sorry about the vagueness, the shock wave is meant for minor adjustments in rpm 200-300rpm or so. Like others have said get your primary right first. I rarely adjust my shock wave only when I'm having rpm drop due to snow conditions bogging the sled down. If you have the room for more boost that'll have the same effect on rpm bringing revs up. I was running as much boost as I could last year and I was short 200-300rpm in deep powder adjusted the shockwave and brought the rpm's back where they needed to be.
A lot of guys don't like the shockwave helix, I've had no issues with mine but only have 600miles or so on it. I'm by no means a clutching guru, my setup came from Dustin at outlaw it works well for me but I'm sure I'll have to change again as I'm running more boost this year.

 

[2Huskies]

So this helix allows you to change the Rpm on the fly?

 

[2Huskies]

Also, since installing this turbo I have massive ice build up. All over the sled, skid, tunnel, under the tunnel. How do you mediate this?

 

[Powder Man]

It's not on the fly, there's a set screw you loosen then turn the helix one way or the other for rpm decrease or increase. Others might not like it but its worked well for me.
The ice build up I haven't experienced that much, but our snow is not super dry fluffy snow. I'm not sure what to do to fix that, maybe a turbo blanket to insulate the turbo and keep it from melting snow so bad.

 

[801]

Well I have this to throw out there~ I have bashed the Groomers hard~~ as everyone knows~ but i did have the opportunity to ride CBP's sled this past weekend~ he has got it down~~ the turbo is sweet~ as i am familiar with them also~ this is a sweet setup he has~ carves really nice and the way he has his suspension is tits!!!!!!! what ever ya do~~ DON'T CHANGE IT!!!!!!!! it came up on one ski with ease and would stay there without effort~I am really impressed~ i have been a ski-doo and polaris owner for years but i could carve easier with this than i could my 2013 RMK polaris~ so much so that i could see one in my future~~ Thanks Chim Chim and Christopher~~ the trip was a real eye opener!!!

 

[christopher]

This is one of the real mysteries we have not figured out.
Chim-Chim's sled ABSOLUTELY lays over easier than mine does!
He has the bone stock suspension and I have the SKINZ/KMOD.
And his is MUCH more agile in laying over than mine is.