Boost Calc

[zoomer]

If I'm doing this Boost Calculator thing right, based on a .060" head shim with the head gasket gives me .077" for an Apex I can run 91 with

12lbs @ 1000'
14lbs @ 5000'
15lbs @ 8000'
16lbs @ 10,000'

and also I can run

20lbs @ 1000' on 100 octane?

Is this right? That seems like a lot for both 91 and 100 octane.

And if I'm right and you just use the stock head gasket with NO headshim you can only run

5lbs @ 1000' on 91?

 

[FLYBYU]

I run 20 a little above sea level but i use 116 octane better safe than sorry. I wouldn't run 20 at 1000' with 100 octane

 

[quebecmoutainrider]

ran 2 tanks of race at sea level..19psi..run 14psi all the time at sealeve..pump 94..head shim.injectors pump ,studs..,and even my tech said it was ok..these numbers you have were pretty much the same he told me..thats why I went with the stage 2..to use 22psi above 5000..as for no shim..wouldnt go over 7psi at 1000..

 

[googlerock]

To see what the effect of boost pressure and altitude is on your static compression ratio, simply enter the three variables and the calculator will display the results in a new pop-up. This will give you an idea of what happens under boost and also how you should plan your engine for your target altitude if it is for racing or daily operations.

 

[zoomer]

Just got an email back from Leipheimer Yamaha in Butte, MT (MCXpress USA dealer) The new MCXpress 290 kit runs 14lbs of boost at sea level on pump 91 to get you up to that 290hp mark. And it will auto compensate for air pressure change. I will be looking into this kit a lot more in the near future. I just may have to buy one.

 

[quebecmoutainrider]

Thats imposible..that would mean you are getting 10hps per pound...more like around 6-8hps per pound.my sled is at 14psi and its only at 261hps on the dyno...290 at 14psi.. I wish..that means I have 370hps at 22psi..
check it on a dyno and you will be surprised..ok depressed..lol.

 

[mulot30th]

Thats imposible..that would mean you are getting 10hps per pound...more like around 6-8hps per pound.my sled is at 14psi and its only at 261hps on the dyno...290 at 14psi.. I wish..that means I have 370hps at 22psi..
check it on a dyno and you will be surprised..ok depressed..lol.

A few years ago I had same depressing results as you get now.


But since then made a turbo sled (my apex mountain) and got 280hp. at 11 psi.... and even then I left a few hp on table (too rich and too much octane for that boost level) but making hp was not the goal that day.

 

[Blue shadow]

Mulot30th how is the osp sled running?Any good speeds on 660 ft ?thanks

 

[mulot30th]

The osp is running good this sled rocks!

Only issue so far is rear suspension bent a few parts last testing day, not gone out since.



Here is a quick video of last run when sled spun bad off the line and suspension and sprocket failure occured about 400 ft from start (I suspect it was beginning to bend before that run):

http://www.youtube.com/mulot30th#p/u/5/8drOPcxexX0


which resulted into this:

 

[Blue shadow]

She sounds good at take off ,thanks for the vid.That thing got a lot of power to do damage like that.