boost=horsepower

[sheetwright]

I was wondering, what is the rule of thumb for boost to horse power? Is there a formula for this? Say some one says they have a sled with (X) amount of horsepower now, and they want to add (X) amount of boost. This new added amount should add how much horsepower to the sled? That is what I am trying to figure on my new sled setup. A lot of people say not to run anymore then 10-12lbs for trails on a Nytro. BUT this amount of boost equals how much horsepower per pound of increase (for a lack of wording)? When someone tells me that by adding 10lbs to my stroked sled, I should end up with aprox. 250 (+) horsepower. I want to know how they come to that? Is there a chart, or just a guesstamite?

 

[woodsrider]

Use the sticky at the top of the forum page

 

[Blue shadow]

For every pound of boost is 10 hp more

 

[mulot30th]

For every pound of boost is 10 hp more

on a 150hp engine and turbo speaking.

blower is more like 8 to 9 per # of boost.

 

[HURRICANE]

There is alot of things that affect the amount of HP per # of boost.For example,on an apex engine,if we port the head and gain 20hp pre boost,as a rule of thumb,we should double the HP at 14.5lbs boost to 40hp.BUT,we also gain HP per # of boost.So,if we can gain just 1hp per # of boost,that's an additional 14.5hp.That now totals 54.5hp more at 14.5lbs boost.This is real world stuff.We have dynoed trail sleds to 300hp at 18lbs boost with stock motor and a Bender kit.But our big bore race engines make 400hp at 18lbs boost,properly boosted.The difference is huge.

 

[sheetwright]

There is alot of things that affect the amount of HP per # of boost.For example,on an apex engine,if we port the head and gain 20hp pre boost,as a rule of thumb,we should double the HP at 14.5lbs boost to 40hp.BUT,we also gain HP per # of boost.So,if we can gain just 1hp per # of boost,that's an additional 14.5hp.That now totals 54.5hp more at 14.5lbs boost.This is real world stuff.We have dynoed trail sleds to 300hp at 18lbs boost with stock motor and a Bender kit.But our big bore race engines make 400hp at 18lbs boost,properly boosted.The difference is huge.

That is the confusion. Since I am allready running some motor and after market mods. Engine has been stroked, and Pat left some slop to run boost. Obviosly some of the mod's I have now will have to go, to make room for the boost kit. Right now I am supposidly around 170hp without boost. That is why I am asking. It is a stage two MPI kit that will be going on. I assume some of the pro's with this stuff go by their years of experience, and gut feeling prior to dynoing. Just didn't know how close the sticky info gets you when the sled itself isn't all stock? Guess I will go with 10lb's equals 100(+) extra horsepower? Which if right I think the 10-12 range will be right in the ballpark I wanted to be. I remeber a guy telling me a couple weeks ago that I should go more on the horsepower. Since he has had guys come back spending extra money later to create more power. when they could of just done it cheaper at once in the begining . It is just figuring out the data to make the sled take you just to the point of a skid mark , but still managable on the trails . Such a fun decision to make, and figure out. Thanks for the pas,t and new help, Dave

 

[genesmob]

HP per lb of boost

Im sure this doesnt work all the time, so dont shoot me, but its usually pretty close with similar intake temperatures.

Engine HP divided by 15 times Turbo boost plus Engine HP = Turbo Boosted HP

Example=Average RX1 with lowered compression for boost 135hp divided by 15 = 9hp/lb times 15lbs boost =135hp plus 135 engine hp = 270 total hp.

 

[sheetwright]

Thanks for a lll the help guys This should get me close