With all these mods it begs the question of what is "significant"... so what is a noticeable difference... personally whenever I do a mod I go out and time the 100-160km/h (62-99mph) in a 3rd gear roll on on the same strip of road @ 20C (68F)... my stock porsche (PSE & K&N) can do it in 5.7 seconds in 3rd gear... ALL DAY LONG. I believe this is a good measure because your starting at 4000rpm and finishing a few hundred RPM shy of redline; also your not shifting gears to eliminate variables... I start the watch the same time the accelerator pedal "slaps" the floor; just to be accurate; I also make sure temp and humidity are within 10% of eachother during runs. I have come up with 5.7 (+- 0.1) seconds consistently on over 20 runs.

So with a chip and headers... how much time can you shave off this type of run?

Fabspeed cold air intake claims you can reduce 3000-6000 rpm by 0.42 seconds and for the low $$ spent on cold air intake that is very significant... do you think a chip will reduce this measurement by a full half second? I'm doubtful...

At the end of the day, many will hit the dyno only to see if they have made more HP... but the real test is a timed run between speeds or a point A->B test (accurately measured) which shows a decrease in time; cause in the end... thats what we are all after... and from what I've read on other threads about tuning... the best dyno graph doesn't necessarily equal the best performance on the street...

my 2 cents.

 

After looking at these 2 before and after graphs the torque curve is EXACTLY THE SAME... what's up with that... more HP but exactly the same torque? hmmmm...

 

yes i would agree that real world numbers are more valuable but i would have to argue the method of testing.

it's really hard to see noticeable real world gains from incremental HP increases. i think even tuner 9ff tuned a 3.4L and gained 30 BHP they on recorded gains in the tenths of a second (sorry, need to dig up the artice for the exact number). let's say ~3/10ths of a second for 30 BHP. well, what's the margin of human error? ~1/10th for the fastest of reaction times (think drag racers) and ~10/10ths for the slowest. there's such a huge variance that "stopwatching" can negate any performance gains.

you and i have been PMing each other and debating on various testing methods and i am just bringing it out for further discussion with others (not picking on you )

where you can see the small gains on an NA996 is on the track. being in the 4500 to 7200 rpm range for most of the time you will benefit from HP increases up high in the rev range. on the street what you need is more torque. get a supercharger. with small gains that you think may not translate well to the street then why mod at all?

 

Carlos,

reaction time doesn't come into play here... you hit the stopwatch at the same time you slap the accelerator...

try this: tap your hand on your desk and your foot on the floor at the same time... you can do it exactly the same time on your first try I bet.

Next time you hit the stopwatch is when the needle crosses 100... its a no brainer... in fact pick your favorite stretch of road and do the 3rd gear roll on as I have desribed and I bet you will not be off by more than 1/10th of a second... do 4-5 runs on the same day to negate temp and humidity differences and you will see how accurate this method is; make sure you start your roll on at the exact spot on the road each time to eliminate grade differences that are not visible to the human eye.

But if you say 30HP is only worth 3/10ths of a second...well... is that of the 0-60 measurement or some other measurement... 0-60 3/10ths would be significant! it really depends on the measured interval.... I mean Fabspeed claims 0.42 seconds from 3000-6000 rpm... that seems to be pretty good value for the $$ spent no?

on my Volvo C70 I shaved off 2.5 seconds from 100-160km/h!!! but these are the kinds of gains you get with modifiying a turbocharged car.

Seems to me that Dyno tuning works best... unfortunately here in Toronto there is nobody to do this.... oh well.

 

i agree, the start is a no brainer but it's when you stop the stopwatch is when the variables kick in. anticipation leads to a large margin of error, especially when driving AND looking at the speedo AND making sure you stop the watch.

i keep forgetting that my obdii scanner came with performance measuring software which measures load, elapsed times, etc. i gotta find a level stretch of road and do some testing. i think you need to get a scanner which has this function to be absolutely sure. or even better, get an AIM or motec data logger. i wanna get one of these with the digital dash, just the geek in me

as far a 30HP being worth 3/10ths was hypothetical. i was just emphasizing that the margin of human error can be more than 3/10ths giving you skewed results. btw, the fabspeed airfilter change/slilcone hose has got to be the biggest joke! c'mon 0.42seconds?

you're in T.O.? i spent yr3 to yr17 in T.O., i went to brebeuf college prep. i've heard that things have changed. more high-rises.AUTOENGUITY-speedtracer

 

Carlos,

there is no anticipation.. I don't know where you getting that from...... your on a clear road with no traffic and your looking for the needle to hit the 100 mark... and as soon as they enter the 100 line you click the watch... that's it test over... the needles in these cars move slowly... why don't you try it the way I've described it and you'll see how consistent your times will be! give me the benefit of the doubt and try it.

As for the Fabspeed... I really don't know... never tried it; don't know anybody who has it... that is what is advertised on their website...

Peter

 

i guess this is where we have to agree to disagree.

there is ALWAYS a margin of error when it comes to human reaction times. there is a margin of error with electronic measures but at a much much smaller percentage. when you are watching the needle reach the mark you are ANTICIPATING when you should stop the watch. it's simple as that. you even said "your looking for the needle to hit the 100 mark", well, you are anticipating the moment when the needle hits the mark. just hope you don't hit stop just before the mark or just after the mark otherwise there will be error.

when there is indeed no anticipation and you stop the watch when you physically see the needle hit the mark then you are relying on human reaction times. the time it takes for your eyes to see it, your brain to process it and your body to react, can be huge (relatively speaking, we are talking tenths). again, the best times being 1/10th of a second and average 3/10. if your body reacts @ 3/10th of a sec than electronic means then your measurements are 10%~33% off or even more. the error will be worse when comparing it to other "human" timed results. you see wher i am going with this...

i'll give it a go but the scientific mind in me already knows there WILL be error.

 

I had the B&B headers, Fabspeed intake & Gemballa exhaust on my car & didn't notice any acceleration differences (sound was better though) until I got the GIAC chip upgrade. Seemed to be able to use that extra inflow/outflow a bit better when I did the chip upgrade.

 

i felt the same. without the chip's revised timing and fuel tables the engine can't take advantage of the better flow. without the giac the engine breathes better but doesn't take advantage of it.

 

If you're looking for performance for your mod money then take your OE headers and have them ceramic coated, not the aluminized heat paint but real plasma applied ceramic material. This will reduce heat migration by 30-35% and the motor will breath better due to the fact the header gas temps stay hot internally aiding in the scavanging effect of the headers. The hotter you can keep the gas the better off you are. You can spend $2-300 or $1500 for the same potiential performance gains. Your call.

 

1. set the cruise control @ 60 mph and when your ready slap the pedal and hit the stop watch at the same time - no error

2. When the needle hits 100... well you just have to get good at clicking the watch when the needle gets there... you can do it... just try it and you'll see you'll be within 0.1 second each time but MAKE SURE YOU ARE ON THE EXACT SAME STRETCH OF ROAD.

other than this method I don't know if there exists a device that can measure speed intervals... I know there is G-Tech pro but that device is not designed to start runs from speed A to speed B... but instead measures the time from certain speeds as you accelerate from a lesser speed... this is innacurate because it really depends on launch characteristics and how fast you accelerated from the get go.

 

check this link out:

AUTOENGINUITY - speedtracer

 

Carlos,

I think you found what were looking for!

cheers
Peter

 

haha, i already have it! i was suggesting it to you because you said "I don't know if there exists a device that can measure speed intervals". well now you know. it's definitely more accurate than your thumb .

 

Well after all this info, It sounds like I will be wasting approx. $4k to install cargraphic headers and cats to the existing cargarphic exhaust that I have?

My friend has a C2 (couple) and I have a C4 (cab) both are 2002, and there is a difference off the line. I would be happy with the same torque that his STOCK C2 has.

Any additional thoughts?