If I could get those types of numbers from mine I'd be a happy camper... But between my gears (switching to 4.30s), 12 bolt, and a denny driveshaft, there's probably going to be quite a bit of parasitic loss next time I get it on the dyno... I'll be happy if the net result is in the 380 rwhp range.

 

Are you still running the stock injectors? If so, I wonder if you are running out of inj at ~ 4000rpm? My TQ & HP really starts to climb at that point....or maybe it's the restriction of the stock lid.

 

Yes, still stock injectors. I'm sure I'm giving up a considerable amount with the stock lid. I think I'll have Jason e-mail me my stock tune when I get HPT, and start from scratch and try to do a decent SD tune. I've been lurking around the forums at HPT's website, and found that awesome step-by-step sticky. I never liked that MAF monkey business anyway. Once I get that nailed down, hopefully my numbers and A/F will look more like I think they should.

 

Well since the car is going rich at 4000 rpm I'd say he's not running out of injector.

 

Ok, where to start, First I want to say thats a nice setup and I am not bashing you, just pointing out some places where you've made a mistake.

1. "Those are the SAE numbers" No they are not, they are the uncorrected numbers, the numbers on the second graph are STD correction which reads higher than uncorrected most of the time.

2. "The uncorrected numbers are 395.1/364.9" No, thats the STD corrected numbers and its not even that on the HP, Win Pep always screws up the little point when you let off the gas, note the big up spike at the end? thats a smoothing factor problem. With out the spike the max is actually around 385 rwhp. again thats STD the uncorrected would be lower and the SAE would probly be around 380 with your conditions.

If you use the conditions you listed above, your correction factor is .963 based on this calculator: http://wahiduddin.net/calc/calc_cf.htm

So, if you take your graph of uncorrected (winpep, without the spike) you are at 377 peak rwhp.

Ryan K.

 

Duh, I guess I shoulda looked again at the A/F graph....sorry.

 

You are of course quite correct. Those are the STD numbers, and I previously amended my post in the Dyno forum about this, but forgot to do so here. According to the rest of the printouts I got, the STD numbers are .99 of the uncorrected numbers, making uncorrected HP/TQ 399/369 (approx.). Applying the weather data into the SAE equation nets a result of 383/354.

Yes, the spike at the end does indeed make the peak HP number somewhat inaccurate. However, when it hit the rev limiter (shown by the dip before the spike) HP was still climbing. If we assume a HP curve in line with what is shown on the graph, that would put HP at the RPM at which the spike occured at only slightly less than the spike itself, I would say in the neighborhood of about 1-2 HP. With each delineation of the graph equaling 5 HP, that would put the peak HP before hitting the limiter and the peak HP of the spike at a little less than 5 HP apart. Due to this, the actual SAE HP at that RPM would be approx. 382. Pretty good guess on your part!

Man, math sucks! It took me so long to track down equations and convert everything that my Subway sandwich is soggy now.

BTW- Don't blame me for claiming those first graphs were SAE, blame WinPEP 7, cause those are the numbers it spit out. The output graphs I exported all say CF: UNCORRECTED no matter what conversion factor I graph it under. Keep in mind, this is the same program that gives me different peak HP/TQ numbers every time I open my dyno runs, by between 5-10 HP/TQ! Go figure.

Don't worry, no bashing taken!

 

Damn! I wish I would have found that! I just found the equation and did the math. My math was good though, cause I did get the same CF, but I rounded it to .96.

 

don't worry bro when you get back back up here i will take care of all that stuff, hopefully 1.6 will be out and then it's mafless for you too. car runs so much better. Let me know when you get back in town, and we will tune you right up, mught have to do some dyno time, or borrow a wideband from someone, but hopefully will have access to a axle dyno real soon.