I finally scanned in my dyno results from my Y-pipe install. These include runs from before the install, after the 1st piece of the Stillen Y-pipe and also after the Federal exh manifold and 2nd piece of the Stillen pipe. Here's the link:

http://www.desertpearlmax.homestead....noResults.html

 

Looks good, Desert Pearl. Thanks again for providing us with such valuable data.

 

yeah man....THANKS!

 

Thanks for providing the data man. Like I figured in the Data, there is no difference with switching the pipes. All of the difference is in the programmng of the ECU itself.

 

It was also 10 degrees cooler during the full ypipe run...which might explain the 1hp difference

 

10 degree's cooler might mean more hp, but the Dyno calculates the temp, baromemic pressure, etc and should come out to close the same reading each time. Every dyno session varries on its own.

 

So there is a default temp/barometric pressure/etc that every dynomat adjusts it calculations from so temperature etc isn't a factor during the dynomat...only the car/mods can affect it?
Basically the same car should dyno the same in 50 degree rainy weather as apposed to 90 degree dry weather?
If thats true...Cool!

 

From 4000-6000rpm he gained an average of about 3hp. Also there is a 5hp/3tq gain at 5000rpm. Also it seems to show a loss of torque below 3800rpm. Now even though his peak power or torque didn't change his car will accelerate quicker than before. BTW Desert has the throttle response above 4000rpm improved at all since the manifold swap?

 

This is true. The dynojets adjust back to 0' elevation and 60F temperature. The CF number shown on all dynojet plots is the correction factor. If you go to my dyno site linked above and click on one of the raw data files you will see both the uncorrected data and the corrected data. This does give shops that want to inflate their dyno results a means of doing so. If you want to make an intake look like it gave you more power, just put a Bic lighter infront of the temp sensor, the CF will shoot up and give you higher corrected HP numbers. The good thing is that this number is always shown on dynojet plots, so be sure to look for it.

 

If I read the dynos correctly - and it is hard to because the torque colors are not identified on the combined graph -the manifold addition showed a substantial loss of low-end torque and hp up through about 3500 rpms compared to the 1 part y.

Looks like 15 ft lbs and as much as 10 hp. I'd say you need to look at the rpm data from even lower before considering this mod.

It may be faster than stock but no way will it be faster than with just the 1 piece y. In fact, I just looked again and it was even lower than stock through about 3300 rpms.

 

I bet a Coke that the federal dyno plot simply shows lower torque below 3500 because the dyno operator didn't go full throttle until ~3500. If you look at a lot of dynos, you'll see a huge difference in torque at the lowest shown rpms between runs sometimes. Even with the cars in the same condition, the numbers at lower rpms vary widely...simply due to the operator not flooring it soon enough.

I personally like it when the dyno operators floor the throttle from as early an rpm as possible so that you get a snapshop of the true power curve through all rpms...but unfortunately a lot of operators think the customer only wants the peak numbers, so they only focus on the higher rpms for full throttle data collection. I guess a lot of customers only want the peak numbers, though...maybe don't really understand the importance of non-peak numbers as well.

 

This was it exactly. I recall him easing into the throttle in this run. He was trying to keep it from downshifting and I guess he forgot that he could just punch it as he did a few days earlier. We made a couple of runs after this one, but we didn't allow the car to cool down between runs, so they netted less power on each consecutive run.

 

when you dyno an auto, shouldn't you stick it into 2nd gear and then floor it? You would probably get a more accurate result if it stayed in the same gear.

 

Nope, Autos you need to use 3rd gear with OD off. It's the most accurate gear.