MCX240 Boost on Pump Gas

[Northernboy]

I have the MCX240 kit with the head shim running at about 1000'. I am running at about 11 PSI on premium pump gas (91 Octane). I like the power but can I go more? MCX says max is 13PSI, but using the Boost spreadsheet 11 is 91 and 13 is 93. So am I save, should I add some Torco accelerator, so I go with meth? I guess keeping A/F ratios below 12 will help as well. Just wondering what save boost with 91 would be.

Thanks
NB

 

[kinger]

11psi is pushing it IMO, throw a dab of torco in and 13 is fine. If you do 13 I wouldn't hold it to the bar very long maybe 5-10 seconds a crack.

 

[helmic]

boost

I run 12##on 91 but add 4oz of torco per tank and its working for me...

 

[machzrobbie]

I have the MCX240 kit with the head shim running at about 1000'. I am running at about 11 PSI on premium pump gas (91 Octane). I like the power but can I go more? MCX says max is 13PSI, but using the Boost spreadsheet 11 is 91 and 13 is 93. So am I save, should I add some Torco accelerator, so I go with meth? I guess keeping A/F ratios below 12 will help as well. Just wondering what save boost with 91 would be.

Thanks
NB

Pretty sure you have a 60 thou head shim + head gasket gives you .077 - plug that into the calculator and you get 13# @ 91 octane - and 11# @ 89.9 octane. I'm running the same shim on a MPI stage 2 and running 12.5 - 13 # on 91 pump gas.

 

[Northernboy]

The head shim is 0.075" and this is on a Nytro are the calculations right?

6 lbs = 84.9 Octane
8 lbs = 87.1 Octane
10 lbs = 89.3 Octane
11 lbs = 90.4 Octane

All at 1000'.

 

[machzrobbie]

The head shim is 0.075" and this is on a Nytro are the calculations right?

6 lbs = 84.9 Octane
8 lbs = 87.1 Octane
10 lbs = 89.3 Octane
11 lbs = 90.4 Octane

All at 1000'.

sorry I did my calculations on a Apex - Nytro : with .075 shim I am getting different values than you - are you chaging the head shim values and adding the altitued??

 

[Northernboy]

This is what I come up with, is there something wrong with my numbers?
Thanks

 

[Triplerev]

What is your elevation?

 

[Northernboy]

Does anyone know where I can get some Torco Accerator in Ontario?

 

[Northernboy]

I found some and will be adding about 4oz per tank full just to be on the safe side. BTW loving the boost and would be nice to go higher!!!

 

[TBird]

Add an fuelpump, an FPR and do a remap, voila 270hp.

 

[Northernboy]

TBird...Maybe next year....boost is addictive...

 

[TBird]

Agree, i'm in the same boat
A while back, around a year ago, my boost fever was really bad, had plans to add meth, add a bigger turbo, beefing up the engine a.s.o. to start with i added some good fuel and rised boost as much my turbo could handle, what i noticed then was because i had to change my clutching to keep it off the limiter the sled got worse to drive in the trees and in really tight spot's, so right now i turned the boost down again, did some other mod's, and i'm really enjoy my 310hp Apex, what i want to say with that is that i believe that every sled / sledder has a sweetspot when sled and sledder works in harmony, that's how i feel anyway, hp isn't everything, it's every mod done to the sled put together working in harmony, do i make any sense, maybe little to deep?

 

[TURBLUE]

Agree, i'm in the same boat
A while back, around a year ago, my boost fever was really bad, had plans to add meth, add a bigger turbo, beefing up the engine a.s.o. to start with i added some good fuel and rised boost as much my turbo could handle, what i noticed then was because i had to change my clutching to keep it off the limiter the sled got worse to drive in the trees and in really tight spot's, so right now i turned the boost down again, did some other mod's, and i'm really enjoy my 310hp Apex, what i want to say with that is that i believe that every sled / sledder has a sweetspot when sled and sledder works in harmony, that's how i feel anyway, hp isn't everything, it's every mod done to the sled put together working in harmony, do i make any sense, maybe little to deep?

man i totally agree....I liked me apex when it was 260 with stock pistons at 12psi then i do mine with lc pistons @15psi..... now im trying to get the throttle response back..cause we do alot of tree riding....good comment