Horsepower Increase

[joe117]

If you were getting 400 RWHP to the ground you might do a 1/4 mile in 12.6 seconds. Note, these are just ballpark figures but they are probably about right. If you were able to pick up 40 extra horsepower and get it to the ground, you would probably see about .3 second improvement in your time. That would be less than 2.5 % improvement. Others may disagree but I don't think you could feel that. If you put a 100hp nitrous kit on the car, you would probably drop 1 second from your 12.6 second time. I know you could feel that. The nitrous would give you the power right from the time you push the button. A cam and heads job might not give you anything at lower rpm.
My bet would be that it would take 50 hp to give you a small seat of the pants feeling that something good has happened.
You will probably hear from lot's of folks who swear that they could tell the difference when they put on smooth tubes. They must have very sensitive seats of the pants.

 

[GTS Bruce]

Probably take at least a 10% increase to feel anything.I think what you feel with the filters and tubes is more responsiveness. Bruce

 

[Dr Roof]

Not sure, i went from Bone stock to 800rwhp no in between here! As you can imagine I felt the difference immediately!

 

[phiebert]

I agree with GTS Bruce, its a percentage thing. I have done mods that apparently bumped HP by 15 and didn't feel them. I changed exhaust and "think" I felt that (probably a 30 HP boost). But when you are starting at over 400 it is a small percentage. It's all relative, if you had a 15 HP boost on a VW Bug you'd probably feel it a lot.

To be honest, I have a 225 HP shot of Nitrous and don't feel that as much as I expected...so maybe my feelers are just broken!

 

[NJVIPER]

...when do you actually experience, not "feel/imagine", the difference in acceleration/performance? Every 5, 10, 15hp...how much?