144 psi to much for pump gas?

t30mg

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Brush Prairie Wa

• Mar 1, 2017

• #1

I installed a mcb fix kit with forged pistons in a 13 pro this winter.
I mentioned on another thread that it has 144lbs psi and another helpful SW'er mentioned thats high enough to cause DET on pump gas.

I only run clear 91, is this really a recipe for DET on an otherwise stock sled?

Stock and fresh Doo's spec 150 and run pump gas without probs, but perhaps their timing accommodates the higher compressions?

 

diamonddave

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• Mar 1, 2017

• #2

That caught my eye in your other post. It will depend alot on lots of variables like altitude your riding and your squish. Not familiar with their kit but some fix kits will tighten up squish to the tight side. But 144 sounds pretty high to me for pump gas.

What altitude are you checking compression? Is that same hot and cold?

A stock Pro/Axys will have 125 at sea-level.

 

A

adamg

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Mar 14, 2011

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Saskatoon, SK

• Mar 1, 2017

• #3

t30mg said:

I installed a mcb fix kit with forged pistons in a 13 pro this winter.
I mentioned on another thread that it has 144lbs psi and another helpful SW'er mentioned thats high enough to cause DET on pump gas.

I only run clear 91, is this really a recipe for DET on an otherwise stock sled?

Stock and fresh Doo's spec 150 and run pump gas without probs, but perhaps their timing accommodates the higher compressions?

Click to expand...

Doos inject fuel differently, can't really compare their compression numbers.

 

BILTIT

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Lloydminster, SK

• Mar 2, 2017

• #4

At 2200ft 145psi is too much for pump on my sled, i run 30%av. At 8000+ft you should be fine on pump.

 

t30mg

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• Mar 2, 2017

• #5

diamonddave said:

...
What altitude are you checking compression? Is that same hot and cold?

A stock Pro/Axys will have 125 at sea-level.

Click to expand...

I checked it warm at 300' elevation. I ride between 2500-4k'

 

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kgra

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• Mar 3, 2017

• #6

At that elevation should prob run 94 octane pump fuel. you could try to run the sled in ethanol mode with non ethanol fuel as it will add fuel and reduce timing slightly. As mentioned squish height plays a large role in timing so you'll probably just have to play around.