Minimum increase in h.p. to actually feel it?

Not the early europium associated with a modification but in day to day driving what is the minimum increase in h.p. that is required to make a difference? Back in the day it was an increase of somewhere around 35-50hp although I hear some folks swearing that they feel and can use a + 5 hp increase. So with the Cayman what are the feelings of those who have actually measured before and after results of their modifications?

I can certainly "feel" 20 at the wheels, less than that I don't know.

I noticed when I had the catback installed and my guess is that is maybe 15 on a good day? Depending on the mod, like desnorking, the sound may make you feel like something is happening.

Another way to look at it is that less weight gives the effect of more HP. So how many pounds equates to what HP? (I don't know) But the CS tank is 16.9g. 1/2 half tank is say 8.5 gallons at 6.2 pounds of 93 octane (depending upon temperature or something like that) equals more than 52 pounds. Do you think you can feel the difference between a full tank of gas and half tank of gas? There is a calculator here Ray Hall Turbocharging - Java drag racing calculator I'm just using 3300 pounds as an example plug in 295 hp at 3300 pounds get 1/4 mile in 13.03 plug in 295 hp at 3250 pounds get 1/4 mile in 12.96 I'm guessing you can't feel the difference between 50 pounds. But what about losing 1/2 the gas and your 150 pound passenger and you get: 12.76 secs. I'm still guessing in daily driving your never going to feel that. So how many pounds is the equivalent of how much HP???

As this is a subjective question I think I can give a likewise subjective answer. So can I tell the difference? desnork: No Evo: No Headers and catback: Yes Flash: Ask me in 2 weeks time. Less weight? Full tank and passenger Vs 1/8th tank of juice and no passenger: Yes! So now I drive on empty all the time and tell potential passengers, " dont come you may get whiplash or a sore shoulder from going around corners". LOL :crazy:

Now this gave me a smile Best

I think the average person can only feel 10-15% On a CS, you shouldn't be able to feel 20 hp

When I "modded" my 2.7 I could tell the difference. That was 50HP extra horsepower that no one disputes. Big difference. Half of that would be 25. I would be able to feel 25. No question. In my 2.7, I got to the point where a track instructor needed to be able to "justify his weight" for me to want him in the passenger seat.

Ok, well the "cost" of weight changes is usually estimated at 8 hp/ 100 lbs, so 50 lb weight loss gains you the equivalent of 4 hp. As for how much you can "feel" -- before my Snap Flash, I honestly thought I could feel a real difference changing from 91 octane to 93. Since it wasn't double blinded, I admit there could have been a significant "placebo" effect. The car felt much "revvier". That can't be more that 5 hp gain, right? Since my Snap Flash, I swear I can feel a difference. Scott claims 12 hp gain at 93 hp, but the car really feels more responsive, and my G Timer showed an improvement of 0-60 times from 5.5 to 5.17 without really burning up my clutch (I did get a 4.7 time, but I'm not sure I believe it). Greg

If I use the same calculator: plug in 295 hp at 3300 pounds get 1/4 mile in 13.03 plug in 295 hp at 3100 pounds get 1/4 mile in 12.76 Now calculate for HP based on 200 pound difference and it comes up with 12.76 at 3300 pounds - ~314 hp So maybe 50 pounds is the equivalent of 5 hp (more or less). So Santa Fe, can you feel the difference in daily driving with less than a half a tank of gas?

Minimum increase in h.p. to actually feel it? Easy..! I have noticed that whenever you do an expensive modification, you "feel the improvement"... righty away!

So it appears our modders are not as into science (before and after dynos) as I thought. So how about some guesses based on real world experiences? Developing a consensus benchmark that can be tested over time would be helpful to future modders. Surely everyone that has posted about a terrific modificaton has some thoughts.

I don't think I can reliably detect a 10% difference in power; especially if the exhaust sound also differed. I had a car where an increase of only 18 hp was very obvious to everyone, but that was about a 50% hp increase; from about 36 to about 54 ('60 VW stock versus with Judson supercharger). I wasn't sure that I could actually feel a 10% gain (25 hp) with my RSA, but I could sure hear it.

The problem with science is that while it is easy to see calculated numbers, the butt dyno is unreliable unless you can have successive trials and ideally blind testing. Does my car feel peppier? sure. But does it feel peppier because I know what I've done to it or does what I've done to it make it feel peppier... I don't know.

I got about 20 hp (so the dyno says) from my catback, intake & desnork. I will be going back to the same track I went to in June with a bone stock car. I'll let you know if it translates into a better track time.

I can't back it up with any imperical data, but I would suggest on a car to car, seat of the pants to seat of the pants, the figure would best be expressed as a % gain over what ever your base configuration for the particular car. I don't believe a +10 bhp gain in a 600+bhp Viper is going to be very apparent without a lot of sophisticated data logging equipment. I have buddies that race Spec Miata 's, and they'd swear +10 bhp on a 115-117 (ATW) base Miata is something they would pick up on inside of 1 or 2 laps.

Very true, I was thinking about a 295 hp car of course. My very dated experience from my old hot rodding days (what we now call modding) suggested that a 10% increase was the minimum that an educated driver could detect (or about 30 hp on a 300 hp engine). But things have changed so much that a new standard is needed. Vehical weight is also an important factor that has changed.

I would say a 10% difference in power is significantly noticeable.

It will also depend on where the extra HP is. If it is all top end then no way are you going to notice it at lower rpm's. Does Torque follow HP ar would there be different correlations with pre and post-mod? Bill

As you stated, hp and torque are correlated, and different performance mods can affect each somewhat differently. I'm not up on what different mods do to each on the CS, but if one by-passed the primary muffler on a 964, there would be more hp gain than torque gain, but if one by-passed the secondary muffler, there would be more torque gain than hp. If one by-passed both mufflers, there would be a small loss of both hp and torque; at least that's what the trusted tuners claimed.

My last modified car was my new 1980 911SC which had around 200 hp and weighed a bit over 2500 lbs. When I finally eeked out a dynoed 10% increase in hp I remember being disappointed in the everyday use and feel. My buddies went the after market turbo route and I have no idea how much additional hp they added but it was very noticeable (and limited since they tended to blow up after not too long).