i have been wondering with all the possible mods that can be combo'd up in about any way conceivable for our cars-has there been anyone that, say, did a set of rockers, or bolted on a (fill in the blank) and said something like"it sure felt faster" and maybe then did a dyno or track run or 2 and saw an improvement. how calibrated are most peoples butts? thats the bottom(pardon me)line to my question. can an additional 10 at the rear wheels be felt by most? does a change in how the motor sounds throw the butt out of cal? just wonderin.

 

YES

 

LOL.

I haven't yet dynoed my car but have sure "felt" an increase before after relatively minor mods (granatelli, or air foil, smooth intake bellows). Even when it is such a minor increase that it makes only 5 rwhp it somehow always feels as if it is more "responsive" after any new mod. Or oil change. Or car wash. Kind of like wives and girlfriends after you get them a gift--they are always more "responsive" .

 

When I went from stock manifolds to open Hooker LT's I felt a difference. But when I sprayed a 75 shot at the track I didnt feel it.

 

if your car sounds louder (to an extent) it will typically feel faster as well, which is why exhaust mods are so popular with any car. Half the mufflers that get sold for imports might give them 1-2 HP over stock, but since they make the car significantly louder it FEELS louder.

 

There may be people out there with calibrated butt-o-meters, but I never met one. We have cars come into the shop that are modded and the owner thinks are making a lot power and find that they are no better or even a little down from stock! A good driver might be able to discern a difference of 25hp or so. The faster the car gets, the more absolute (vs. relative) change will be needed before the B-o-M can detect it.

And, of course, a mod that makes the car louder will also make it seem faster. Just because someone installed a part, says it "feels" faster, and then dynoed it and found a hp increase of "x", doesn't mean that they can discern a difference of "x". You would need a "blinded" experiement to verify the ability to discern a difference. Try it with and without the mods, without informing the driver.

Rich Krause

 

I can personally vouch for the louder feeling faster effect.

A few weeks ago I had the cats cut out and straight pipes welded in (one of the very few benefits of living in a 3rd world country with no emission laws) I had a few other things done at the same time, one of which was a PCM tune. For the first few days I actually thought they had screwed up the speedo calibration because it felt/sounded like I was going so much faster than what the speedo read Then I checked the speedo with a stopwatch and realised that my B-o-M needed the calibration.

The opposite is also true: Riding my bike I tend to go faster when wearing earplugs as the sensation of speed is less.

I find that my personal B-o-M is a very subjective measuring device, even something as simple as the song playing on the radio can skew the reading! Maybe some people out there have more sophisticated models.

Dutchie
'96 Z28

 

oh the complexities of the butt. so is a 10 hp gain fairly indescernable? at what hp gain do you really go "well that was worth the money" whilst driving. over and above the stock average lt1 output? 40hp?

i do believe that is correct, for sure.

 

catbacks are suppose to be good for 10 rwhp and cai as well but i didn't feel anything when i did mine. I did feel a diff. when i did my headers and those are suppose to be around 20 rwhp. So i would say it takes at least 15-20 rwhp to notice a diff.

 

I agree with that.
I believe that my b-o-m calibration is all screwed up at times. Everyday it seems to be different. When i did my catback it seemed faster but i believe that to be because of the sound. With my CAI i felt it up top better. So i guess my B-o-M does a alright job of detecting hp. But then again my BRAIN-o-M would be a little discouraged if it didn't so maybethats whats going on.