Quote:
Originally Posted by semtex
Okay, the dyno results are in, and they are um . . . somewhat confusing. I went and did dyno runs on both DynoJet and DynoDynamics just like I did last time.
Let's start with DynoJet.
This is the run I did last time, before I had the headers installed:
This is the run I did this morning, after installing the headers:
Kinda underwhelming, right? A max hp gain of 3.31, and a torque gain of 2.1 ft-lbs. I mean, at this point I was thinking "what a freakin waste of money!"
So then I make the drive over to Forged Performance to do a run on their DynoDynamics.
This is the previous run, prior to the headers:
Now here's this morning's results. This first graph shows HP and A/F:
This one shows torque:
So . . . what to make of this? 
On DynoDynamics, I get a gain of +10.8 hp, which certainly makes me feel better. But I get a small loss in torque instead of the small gain I got on DynoJet! I go from approx. 251 to 247 ft-lbs. And that's comparing peak to peak. The delta in the lower to mid rpm range is actually larger than just 4 ft-lbs (unfortunately Sharif partially obscured the lines with his logo).
I'm going to go out on a limb here and say that I don't really trust the DynoJet results. I say this because the shop with the DynoJet is really close to me, and I went and did the DJ run before the DD run, so I'm thinking that my engine wasn't adequately warmed up. Last time, I drove the 45 miles to Forged and did the DD run first, before driving back and hitting the DJ.
Well, the charts are there for you all to look at and draw your own conclusions. My own conclusion from these results is that if you've already done the intakes and HFCs and cat-back, the hp gain you'll get from the headers is either negligible, or at best modest (relative to what you'll get from the other components), and you'll either lose a little torque, or at best gain a negligible amount. Are the headers worth it once you factor in installation cost? I can't answer that for you -- it's an individual decision.
All in all, I have mixed feelings on this (based on the DD results). I like the HP gain. I like 317.2 a lot better than 306.4. But I'm not pleased about the loss of lower mid-range torque. |
This is McFly from
GenCoupe.com Forums - Your Hyundai Genesis Coupe Community
Someone over on our board posted a link to this thread. I'd like to help out. If you don't find this beneficial then feel free to ignore it.
I've analyzed your Dyno graphs. I hope you find this information helpful.
Enjoy:
Why did the 370Z gain 3whp on the Dynojet and 11whp on the Dyno Dynamics?
Answer is that the Dyno Dynamics dyno wasn't done the same before and after. The 370Z continues to make more power the higher the RPM you take it. So, if you short change the car and don't run it to it's highest RPM possible, then you don't get a good reading. They have to run the car to the same RPM on the before dyno, and the same RPM on the after dyno. On the first Dyno Dynamics dyno run they ran the car to only 7100RPM, then on the second dyno run they ran it to 7600 RPM. So, since they ran the car to a much higher RPM the second time, it's only obvious that they were going to get a higher reading, and that they short changed the car on the first dyno run.
If you look at the power that was made at 7000 RPM on both [before and after] dyno run's to make it fair, you'd see that they made 305whp on both the before dyno plot and on the after dyno plot. They made no power, and actually lost power at anything below 7000RPM, in fact. That's how you should be reading the dyno plots, at the same RPM on both the before dyno plot and after dyno plot. Another way to read the a hp graph is to get better resolution of the hp plot... and this is to actually be reading the torque plots. Yes, understand a hp plot and where the gains are by reading the torque graph... and what you see is that there was a loss everywhere, except that the difference disappears at high rpms, and there is no gain/loss.
Put plainly, either learn how to read a dyno plot OR even more simply, you can throw out the Dyno Dynamics readings because the operator screwed up. RUN IT, and RUN IT HIGH!... or at least run it the same.
Hp gain on stillen headers on a 370Z, is about 10hp loss to 3hp gain, depending on where in the RPMs you are... and the gain of 3hp is only for a split second at 7000RPM. WASTE OF MONEY!
People think they know, but they have no idea.
Like I said, If you don't find this beneficial then feel free to ignore it. At the least, I hope I don't get flamed for trying to help out.