dude i'm not calling you a liar or doubting your findings, i'm merely stating that running a 1/4mi doesnt tell you how much power your car makes. there are lots of little things that affect you 1/4mi time, as compared to dyno #'s (which isnt guessing either).

why dont YOU just stick with your stock MAF and call things even and end this discussion?

 

Actaully you can get a relative value for power that your car is making using your 1/4 mile MPH. That value changes very little unless you screw up big time. Of course things like weather are factors when at the track but if you switch MAF's and you pick up 3 mph on the same day, you have gained some power. How much power you would have to put it on a dyno to find out.

 

what????

i mean that you have a much HIGHER probability of error with a 1/4mi run than on a dyno. on a dyno, all you do is strap down, and then slowly run your speed up.

a 1/4mi run, wow, you have to get your tires to hook, you have to shift PERFECTLY, what if the wind is blowing??just suggesting the possible errors.

 

Actually the mph on a 1/4 mile run is just a figure generated from the last 100ft. Your luanch has minimal effect over it, and is typically on average within 2 mph. If consistancy was a concern it is quite easy to compare runs with simialr 60fts, and see how much of an increase was genereated in mph. I can give an excellent example in which you would see this.
It is a known fact that not all factory throttle bodies opened 100%. In fact most were lucky to achieve 94% opening. Of course I milled the throttle stop, reset the throttle position sensor and could now achieve 100% throttle opening. My trap speeds before averaged 110.7mph, after the throttle stop I was hitting 113.5mph. Now was that a total gain of 3mph from that stop? No, some of that was weather related conditions. But the car was consistantly faster, I was still hitting traps above 111mph-112mph.
A dyno on the other hand cannot duplicate track conditions. One of those conditions would be moving air, a fan does not have the ability to simulate this. You may not even notice a gain on the dyno, yet trap speeds are obviuosly better which in turn means more power is being made.

 

is this supposed to be common knowledge, or is there any actual research that your launch has minimal effect over your trap speed? I just remember how many fouls people have because of their launch.

your right, a dyno cannot duplicate track conditions. the only difference between a dyno and a track is consistency. Consistency cannot be guaranteed at the track. who's to say that the "air flow" into and around your engine and car isnt better from one run to the next? on the other hand, if you take your car to the dyno, each pull is utilizing the EXACT same conditions as the previous pull. I mean, this is the reason why the majority of tuning (PCMs specifically) are done on the dyno, because of the consistency of the "conditions."

bigbake, what your best et time? just curious.

 

Just FYI, I ran consistently within 3 HUNDREDTHS of my best time with both the Stock MAF and the stock descreened ported MAF.

The stock MAF was consistently 2 tenths faster every single time.

 

I guess when you run 22 passes back to back you get an idea of how your 60ft influences your trap speeds. That is my personal experience, but I have also read that your 60ft is only a small part of your trap speed. It is well knonw that the 60ft is a very large part of your ET. I know for a fact that if I spin a little I can see an increase in trap speed, if I dead hook I will see a slight drop in trap. You can take all of your passes and drop them in Excel and get averages.

The only force that would change between passes is wind speed, all other conditions are the same. I typically picked days in which it was not all that windy, not much fun dealing with cross winds and or strong head winds. When I was speaking of airflow I am talking about the air that feeds your engine, these cars are for the most part bottom feeders, and depend upon the air being forced up from the front air dam. They also work on the principle of a low pressure area under the car.
As far as other weather factors, I always write down the DA for that day. So I have an idea of how much weather effected the cars run. You can also see this on night in which the temperature drops. You might pick up a tenth or two, and you will also see a mph or two through a test in tune at night. That is the beauty of a track run, I know the exact conditions that inlfuence the cars performance.

With stock motor: 11.87@113.5mph (1.59) with a 150 wet shot on stock motor sprayin 2nd gear and up 11.32@122mph (1.62). Unfortunately it was the only run I got on the 150 shot, the very next run I cracked the stock flexplate in three spots.

 

+1

I tuned a car about a week ago that had the LTFTs jacked all up, +12 to +18 ALL OVER THE BOARD.... I was like "dude, WTF have you done to your MAF?"... driver: "oh yeah, I have ported MAF ends on it...."

The thing is.... right after the swap, before fuel trims had re-learned and had a chance to lock high at WOT, it would appear to make more HP on the track OR dyno, as it REALLY leaned out the overly-rich factory calibration. So to credit these MAF ends with making power is a bit erroneous as the tune would have done the same without fucking the car's fueling overall.