Can a Dyno really be that acurate?

Okay, i have a question, i know that Dyno's are very acurate and its good to use when tuning your car and stuff, but what about AIR? like lets say you just got a turbo and need to get ur car tuned and shit, and u wake it to the dyno, and they run your car, but what about the AIR thats suposed to be charged into the INTERCOOLER? i've seen people put these huge industrial fans in front of it, but thats still not even close to the amt of air that will be going into the intercooler while driving! So my question is, does this affect results and there fore lead into poor tuning of the motor? or is this such a slight factor that it doesnt even matter?

Firstly, Air flows over an intercooler to cool it and the fans do a reasonable job as the bonnet will be open.

Secondly, dynos are not necessarily accurate - they are a tuning tool. That is you take your base figure and add your mods and see if there is an improvement. In reality, most dynos will differ in result - always dyno on the same machine. Finally, it's very easy to get false figures from a dyno - I've watched operators set them so that a 25KW Beetle popped over 100KW at the wheels in fun

Cheers

Hmm, so that means wherever i get my engine installed, i will not let them dyno it cause they might say its pushing more power than it really is and get my hopes up :) but thanks for that bit of information, i was curious...... anyone else got any more opinions?

those industrial fans they put up are usually set to spin at around 55mph, or 'normal' cruise speed(like anyone goes that slow:)) to give you a rough estimate of what kind of figures your motor is pushing, but yes dyno's are not 100%.

OHHH, i thought it was like an ON and OFF switch with HIGH AND LOW settings like a regular fan :D

it prolly is, but some have the speed at which they blow the air around.

what about those pricey G-Tech things? Are they accurate at all? Anyone know how they are able to determine a cars hp and tq?

my friend has one and if ur on a HILL or if you are miss the Accelerate mark on the Gtech Pro, it will give u false times, but overall, its okay, but not very accurate, deff not something to measure WHP or anything..... prob only good to measure 1/4 mile time and 0-60 time, but if u wanna do that, get a stop watch, it works the same way!

forget the stopwatch, when i first got my car, i used my cd players track time thingy to guesstimate my quarter mile.

i set my trip odo to 0 and my deck to 0secs, then gunned and turned the deck on at the same time, at the middle of .2-.3 on the trip odo my deck read 17.6 secs, pretty ghetto, but i think pretty accurate.

G-tech things are ok. I tested my Si with intake, exhaust/gutted cat, and chip and it said I have 96 hp, so they are no that accurate

Originally posted by doug294
G-tech things are ok. I tested my Si with intake, exhaust/gutted cat, and chip and it said I have 96 hp, so they are no that accurate

Actually thats pretty acurate for WHP!!!!

No this thing is supposed to test your internal HP