supercharger on apex

[DC5]

Last year it ran 138.9mph with an expert x suspension with a stock Mach z track, 96 trail studs and pump gas.

 

[puddytatman]

That is impressive!

I was just wonderring what amount of boost can you give a SC or turbo on pump 91 fuel and what does that boost equate to in HP?

At what point do you need to start mixing with race fuel?

ptm

 

[sledheadgeorge]

That is impressive!

I was just wonderring what amount of boost can you give a SC or turbo on pump 91 fuel and what does that boost equate to in HP?

At what point do you need to start mixing with race fuel?

ptm

Here you go. This calculator will help you.

http://www.toyzfortrucks.com/boostcalculator.xls

 

[puddytatman]

I thank you for this info and very overwhelming for a novice at this. Now if I am deciphering it correctly is it saying you can run 12 lbs of boost and get 263 HP on pump 90.?/??????? I truly must learn a lot about 4 strokes vrs 2 strokes as it sounds like you can get huge HP on just pump 91 with no worries or reliability issues.

ptm

 

[DC5]

That was 13lbs of boost with lower compression on 91 octane. 12lbs with stock compression on pump fuel is not a good idea.

 

[SoCoRX1]

Im going to run stock compression on pump fuel at 10PSI. Im at 10k+ altitude and am told pump fuel is ok this high.

 

[SPEED]

PTM
I am at sea level ,run 10 lbs boost 240hp dyno,ed . Have stock compression @ 10 lbs boost , sea-level your stock fuel pump will fall short (go to dyno-tech and read article) I run a different in tank pump (higher pressure) To run pump fuel (premium) at this boost BE CAREFUL .I run 50/50 mix ,race fuel and premium. I am not saying you can't run straight premium and be safe all I am saying is to err on the safe side. I have trail rode my S/C home on pump premium ,just took it easy (do not know quality of fuel your getting) with no issue's. When I leave camp and head for the lake to beat the hell out it I make sure I am running 50/50. You will love the S/C for all around use
Art

 

[puddytatman]

I appreciate the honest replies as this is all that is asked. I know when I took my Mach Z 1000 twin to dynotech this year to dyno with the new boondockers system I only had pump 91 as that is what is most available to me. We got 219 using half the adjusters capability but Jim said no way going to let me give more nos without race fuel. I know this is 2 stroke vrs 4 stroke and it appears the 4 stroke has way more tolerance but with the cost of repairing one I rather mix to be safe. Initially I wondered what you truly get for boost and HP on pump 91 that you would not be afraid of holding for 2000-3000 feet WOT at or around sealevel for flatlanders?????

Thanks for replies.

ptm

 

[BlgsRX-1mtn]

I'm a little late on this subject but below is a link to a video of my SCRX-1mtn running a 162x2x15 Challenger track on pump fuel 5 lbs boost while clutched for 10 lbs boost against a Summit Rev 800 151x2x16 with reeds, clutching and a can. I weigh 275 with all gear Robb weighs 180 with all gear.

This was on a alpine lake @ 8600' elevation. The reason for the boost/clutching mis-match was so I could do a quick pully swap for 10 lbs boost one the jetting was dialed in (tested three sizes and was dailed in three hrs later).

The second vid is a climb with the same set-up made 10 minutes after the lake run.

As for reliability, I had 2400 miles on the sled when the SC went on. I now have 3800 miles. A blown blower belt as the only cause to need a tow. I now carry a spare belts (one for the Crank/Jackshaft and one for the Jackshaft/Blower). The mileage might seem low to you flatlanders but the majority of my miles are all in deep snow which create heavier loads on the motor than those seen blasting down the trails.

I can hit 11,700 on a groomed trail which is way over the suggested max rpms of 9800 from MPI. When running a 40% grade hill in 2' of powder my max rpms are 9750. Both of these rpms were taken from my multifunction gauge which data logs max rpms which reset to 0 prior to a 1000' climb and a 1/4 run on the groomed trail.

Jim

http://media.putfile.com/rx-sc-vs-800sum

http://media.putfile.com/BlgsRX-1mtn-w-boost

 

[rxrider]

I run 9.13:1 compression, 16 lbs of boost on pump gas 98 octane RON (equals 93 octane US), making about 285 HP. Beyond 16 lbs of boost I start feeding her racefuel, I've been at 18 lbs once, all I can say she flies making 300+ HP. One have to ride a turbo/SC sled to understand what it's all about.

I run a stock ripsaw 136" with 162 studs, speed tops out at 210 KMT or 130 MPH running stock gearing. Sled has 10000 kilometers or 6200 miles on the meter, 2 seasons with a turbo. Still holding together.