What can you feel, SOTP

[joe117]

If one were to add 25 horsepower to their Viper and thus decrease their ET by .2 seconds. Could the driver feel the change? People perceive changes in light or sound when there is a power change on the order of a decibel. A decibel, up or down, is a power change of about 25%. What kind of power change would it take for a driver to be able to notice on the street?
I'm an old guy. (caution, geez alert) I remember back when most cars had a gas pedal that made slide contact with a bent rod that controlled the carburetor. If you were to put a little grease on the back of the pedal, most people would swear that the car was much faster. We called this a "California Tune Up". I also think most people will say their car is faster if they put louder mufflers on it.
So the question is this, what can you feel, SOTP, for real.

 

[CitySnake]

I have to admit that my "a$$ has plenty of miles on it"

, however, i still can't believe that you can feel anything less than, say, about a 10% increase in HP. The reason for my opinion is that most of a 25 HP (to use your example) increase is only there in the highest part of the powerband (like above 5,000 rpm). The rest of the time the 25 HP is discounted to far less. Unless you drive the same road at the same speed in the same gear at the same rpm it would be really impossible to tell. In everyday driving a typical 25 HP increase will yield only 10 HP for most of the trip (unless you are able to drive like a wildman...well...maybe most do

). Anyway, we ALL want to feel the increased HP after ANY mod so, IMO, with that passionate "need", even after a good treatment of Zaino, I always feel the extra speed resulting from the diminished wind resistance

Just the opinion of a "well miled A$$".

 

[Mike Brunton]

I think, to definitively be able to say "yeah it has more power now", you need a good 30-40+ more horsepower. A Viper will make a good 30 more HP when it's cold than when it's hot, and can make an extra 40 or 50hp on a cold day vs. a hot day. You florida guys might not know the joys of a cold morning

, but I know when I take the Viper out when it's 30 degrees, it's VERY noticeably faster.

I dynoed on a cold day (30 degrees). Uncorrected power was about 460RWHP. I dynoed in mid July. Uncorrected was like 402RWHP. I could definitely tell the differnece there!

 

[SUN RA KAT]

I just had my Sean Roe VEC1 installed 2 days ago and after calling Sean for some advice on the settings, I set it at +6/-16 and could really feel the improved power especially since the 1st gear light throttle bog had almost completely disappeared. In the low and mid range it felt like 20 horsepower had been added. Sean says the average gain is about 15 horsepower, but whatever it is, it is very easily noticable over the stock settings for what it's worth.

Yesterday afternoon I fine tuned the settings, but didn't notice anything really noticable over the settings Sean advised me to start with. I found on my Viper the settings of +10/-20 gave the best results per Sean's instructions. I will recheck these settings when the air temperature gets cooler than the 90+ heat index I had yesterday.

 

[ElDiablo Viper]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by SUN RA KAT:
I just had my Sean Roe VEC1 installed 2 days ago and after calling Sean for some advice on the settings, I set it at +6/-16 and could really feel the improved power especially since the 1st gear light throttle bog had almost completely disappeared. In the low and mid range it felt like 20 horsepower had been added. Sean says the average gain is about 15 horsepower, but whatever it is, it is very easily noticable over the stock settings for what it's worth.

Yesterday afternoon I fine tuned the settings, but didn't notice anything really noticable over the settings Sean advised me to start with. I found on my Viper the settings of +10/-20 gave the best results per Sean's instructions. I will recheck these settings when the air temperature gets cooler than the 90+ heat index I had yesterday.

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I agree, the VEC1's changes you can feel. It is not maybe the HP but the car feels more alive.

 

[joe117]

A VEC1 might give you some improvement in drivability, fine tuning the mix at places where it isn't right. The driver could feel an improvement. I don't think that's exactly what I'm talking about. What does it take to make you feel the increase in power? How much of what you think you feel is real?
Look at all the guys on this board that can't seem to agree if rear gears really make you faster in a quarter mile. Almost everyone says, "I just changed to a 3.55 and wow". However, when they actually run it on the track there isn't much improvement. So are they feeling more acceleration or are they just feeling acceleration in different places?
How much of the SOTP is all in your head?

 

[Chuck 98 RT/10]

Peak HP can be misleading anyway. Low-end and midrange could be increased without much peak.

I knew my RT/10 was down on power, how far? Beats me, but when I put new wires on it the fun was back...and it was obvious.

 

[lleone]

The only thing I know I can feel SOTP is my wife's occasional kick. I can tell the difference in smoothness/how's the engine running, but that's the only thing I'll commit to.

 

[SUN RA KAT]

At part throttle a 3.55 rear gear will accellerate faster than the stock 3.07. Full throttle drag racing causes the 3.55 to spin more in 1st, but more importantly, an extra gear shift has to be done, which is why the 3.07 vs. 3.55 times are so close.

 

[Makara]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by joe117:
A VEC1 might give you some improvement in drivability, fine tuning the mix at places where it isn't right. The driver could feel an improvement. I don't think that's exactly what I'm talking about. What does it take to make you feel the increase in power? How much of what you think you feel is real?
Look at all the guys on this board that can't seem to agree if rear gears really make you faster in a quarter mile. Almost everyone says, "I just changed to a 3.55 and wow". However, when they actually run it on the track there isn't much improvement. So are they feeling more acceleration or are they just feeling acceleration in different places?
How much of the SOTP is all in your head?
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I while back I put a large K&N cone filter on my jeep. I swore up and down that the jeep felt much faster all around but especially on the high end of the revs. I wasn't sure if I just was expecting the car to be faster so I willed myself in to believing it was or not. Anyway, I was giving a ride to a friend and we were getting onto the highway and I punched the throttle. He asked me what I had done to the car recently because the car felt faster. I have no doubt that by removing the huge airbox on the jeep, I freed up more than just a few HP but I can't imagine that I made a 25 HP difference or anything. I definitly felt something and my friend definitly felt something. When I drive another friends Jeep, some year same model, it feels slow.

With the viper, it seems harder to tell. Feeling a difference between 185 hp and 195 hp (the jeep) makes the difference between 450 and 460 hp seem pretty small. I imagine that the fact that the viper has such a hard time putting all of it's power to the ground at low speeds does not help. That being said, it felt to me that the high flow cats, belanger exhaust, vec-1, and smooth tubes added enough power I could feel. I certainly saw the improvement at the track.

 

[Roland L-Ocala FL]

Add 25 HP to a PT Cruiser, and you will definitely "feel" the difference. Add 25 HP to a Viper, and you may not even really notice it. However, if you change the torque band a bit along with it, now you may feel it, even if it is only 10 hp. Sometimes adding Horsepower alone may not be noticeable, but if you add torque along with it, now you will feel a difference. Some mods add horsepower at very low rpms and the torque comes in at lower rpms, while other mods will add hp at very high rpms, and that is much harder to "feel" by the seat of the pants.
My 2 cents worth.

 

[Mike Brunton]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by SUN RA KAT:
At part throttle a 3.55 rear gear will accellerate faster than the stock 3.07. Full throttle drag racing causes the 3.55 to spin more in 1st, but more importantly, an extra gear shift has to be done, which is why the 3.07 vs. 3.55 times are so close.

<HR></BLOCKQUOTE>

I gotta disagree with you on this one. It doesn't have much (if anything) to do with traction, or the extra shift. A 3.45 should be able to run through the traps in 4th, and 2 Vipers, one with a 3.07 and one with a 3.45 with an equal launch, you would expect the 3.45 to be alot quicker, but it won't be.

The problem is that in the 3.07 car, you can run to, say 55mph before you hit 2nd. In the 3.45 car, you might only hit 45. The torque multiplication is less in 2nd gear, so the 3.45 is putting LESS power from 45mph-55mph down to the ground. Of course, when the 3.07 car hits 2nd, it is down against the 3.45 car - but the 3.45 car hits 3rd and is at a disadvantage again.

The key is average power being put down. It's not possible to say "gears will make a car go faster over a given distance" because it often isn't the case. In something like the 1/4, it's a tradeoff of how well you can launch, how far you're going, and how many shifts you will need to make, and into what ratios. Even a 3.55 that can hook often won't out-pull a 3.07. I raced several and never lost to a car with gears and similar other mods.

 

[joe117]

Mike, I think you are right on the money. I don't want to get the gear thing started up again but, it look's like the guys who have done the before and after say that gears don't give a Viper much, if anything, in a quarter mile. And yet, the guys who have just changed gears all seem to feel a BIG boost in SOTP. They must be feeling something. The guys who, posted above, who say they can feel air cleaners or plug wires must be feeling something. Air cleaner upgrades should be a high rpm improvement. Plug wires shouldn't give you much of anything unless you are replacing bad ones. Most seem to agree that it takes more than a small HP increase to make a .2sec change in ET. Can anyone feel the .2sec? That's less than a 2% change. Can you feel the change when you are working out with 2lb extra on your 100lb free weights? Can you tell when you are going 51mph or 50mph? Can you feel 2% of anything? How can we have big SOTP improvement without much, if any, measurable improvement in ET?