Increasing Horsepower doesn't always mean adding stress to internals

MustangLife

Active Member
Jan 5, 2003
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Chattanooga, TN
Just some info I learned today from a local guy, that I never really thought about before, but is common since if you think about.

Increasing horsepower by lets say via uncorking exhaust does not add stress to your engine internals

For example: You have a 380 rwhp blown gt with stock headers. You than add aftermarket headers lets say long tubes to car and get an estimated 40 more rwhp to increase hp to 420 rwhp.

Now you have 40 more horsepower worth of heat and pressure inside the cylinders you would think. But no you haven't.

What tears apart pistons, ring lands, rods, cranks and blocks isnt power. its pressure and heat in the form of pumping losses. Everyone knows that your pistons are pumps working against the crank to produce power at the flywheel. What most people forget is that the pistons are also working to evacuate the cylinders. Exhaust pressure is a very real frictional load that benefits the longevity of the entire motor whenever its lessened.

Even though you gain power with headers, youre gaining that power by relieving resistance (harmful resistance, at that) against the pistons.

Something else to point out is 99/01 cobra guys push there limits farther than us. 4valve guys in boost applications go to 430-480rwhp give or take a few on the stock shortblock, but 2valve guys wouldn't dare to try to push a stock 2valve shortblock to numbers close to the 500rwhp range or so. But we have basically the same rods and pistons as them. But people say our weak link is the rods and pistons. When that is true, but there is alot more involved than that.

I understand that some may agree with this and some of those that are close minded and will probaly try to flame me for this post. Just thought I would share some info with yall.

Josh
 
Yeah... Here is what I will say... I saw Stock mustangs with turbo kits at like 480 rwhp... You can get a stock gt block to say 500 rwhp no problem really... But the thing is reliability... You can do it but something could go in a hour or week or anytime... Forged is reliable at 600 rwhp... As in starting all the time... You gotta compare horsepower with reliability... But you have a good point!
 
Its true, but when you get to some serious blown engines, the problem of compression cant be fixed by simple easy breathing. The non forged pistons usualy found on 2v make higher compression, causing more of that pressure you talked about. It gets to a point where compression is too much for those pistons and you wil snap the rods like twigs :damnit:
Ive seen friends do it to their imports...they turbo their stock engines, take the boost to 15 or 20 psi, and the rods and cylenders cant take the pressure, no matter how good the exhaus or blowoff valve.
 
Right but I think the point he is making is this. If all things are left the same(boost wise)and you say uncork the exhaust and make the engine more efficent then the added power will not add more stress to the internals. Kind of like making a stock motor make more power NA first, say to 300hp then add on a 8-10 psi S/C'er. The engine is more efficent and the boost takes addvantage of it.

That way you will make more power without sacrificing reliability too much.