10 GT3

I dynoed my 02' Carrera with the addition of a K&N 63 series intake and a Fabspeed exhaust.

History:

My baseline dyno earlier this summer was on a Dynojet 248C run at 97 degrees with a peak of 270.1 hp at 6200 rpms run with the lid closed (lid open, it only dynoed in the 230-250's). The low peak is probably due to not using a fan to get proper airflow into the engine through the rear spoiler as it would have while driving on the road.

I joined in with the local GTO club in their Dyno Day event today. A couple of the participants were mentioning that they were dynoing about 20 hp lower than they did when tuning a week ago, but I can't verify this since I did not baseline on this same dyno. My dyno today was on a different dyno of the same type in similar test conditions: 93 degrees temperature also on a Dynojet 248C. Runs were made with the lid open (I don't think lid up or down will effect the dyno with the 63 series like it does with the stock intake). The result was an improvement of exactly 22 hp to 292.1 hp. We did not have a good tach signal for the dyno, so there is no torque curve. It appears to have about the same power peak of 6200 rpms. My guess is that a fan will be necesssary to get enough airflow to match what the rear spoiler scoops in at speed to get it to continue to pull power to a 6800 rpm peak.

Hopefully this will answer some of the speculation questions about these mods since these are real world results. I don't know if the exhaust added 10 hp or the intake added 19 hp, but I can verify I picked up at least 22 hp from these mods together and I am satisfied for the $850 I paid for both. If you look carefully, you can see the car picked up 15-25 rwhp everywhere from 4400 rpms (about 73 mph) up to the limiter.

Russ Murphy

Sweet. I imagine I'll see something similar with my GHL's.

washington dc porsche

Good to know.. What's the 63 series K&N?

LVDell

Unless you ran the car in the EXACT same conditions in the EXACT same dyno at the EXACT same time adding each mod both individually and stepped then you will NEVER know if they worked to the numbers you think.

But it does feel good to see quasi numbers that make you feel like you got your $$$ worth.

10 GT3

This is actually as close it is could get to accuracy. You can't dyno with and without mods at the same time. If you were to make a dyno run with the stock airbox and then switch immediately on the dyno, you won't get the same results as after 2 days of driving under a variety of conditions so the ECU has adapted to the changes. You will most likely lose power with the mods. Some of this has to do with the changes that came along with rediness monitors and OBDii. I tried to do with intakes on my G35 Coupe and it actually lost HP with the performance intake on back to back runs. The ECU requires time to learn the changes and adapt the maps. This is part of the reason why some people don't get CEL lights initially, but get it 50-100 miles when the ECU is learning the changes.

Dyno types were identical. Both were calibrated for stardard temperature and humidity in the morning of the events. The graphs are different because each used a different version of Winpep software. Data logging was the same sample rate. Although there was a 3 hour difference between run times during the day, humidity was within 5% and there was only a 4 degree temperature difference (no surprise with Texas in the summer). Baseline SAE correction factor was 1.04 and modded correction factor was 1.03.

1999Porsche911

At WOT, there is no learning needed by the ECU. Changes are immediate. Also, if dyno's accurately account for differences in temperature, humiidy, etc, why mention what temperature you ran it in? Seems to me, if the calculation was accurate, you could run in 200F temperatures and still get the same adjusted power figures.

However, the calculations are NEVER correct and a dyno should be used as an estimated indication of HP and nothing more.

JimB

Don't be so hard on Carrera. Yes dynos vary from day to day but you have to have something to compare and the 248c seems to be pretty consistent over time. I'd be pretty happy with the results even if they are a little off.

Carrera, what gear were you in? You really should do 996s in 5th which is as close to 1:1 as you are going to get. You appear to be in a lower gear. I guess being consistent is the most important anyway.

Do you have the raw files? If not you should get them. You can download the display software from Dynojet. That would allow you to overlay your different runs.

One thing that is suspicious. Your first run has a big power loss when your cams shift at 6200. Your second run doesn't seem to have the issue. I doubt that has anything to do with your mods so I would wonder why.

Jim

10 GT3

Both dynos were run in 4th gear. I did not plan for the baseline to be done in 4th, they just did it from habit. Yes, 5th is closer to 1.0 than 4th. I intentionally had the second dyno done in 4th to match the first. I do have the Winpep files for both sets of runs. The second is logged slightly different in that there was no rpm signal. It is logged by MPH instead. Fortunately, it is not too hard to correlate the speed data to rpms. I'll try to overlay them and see how it ends up. Keep in mind that the raw data files will not have the corrections applied to them since it shows the uncorrected data. This means there will be even more of a spread between the 2 runs than you see here since there is a greater SAE correction factor on the baseline runs.

As a couple other notes. Not only were both dynos Dynojet 248C's, but they were also both above ground dynos. Both dynoes were located in the back of each shop with the rollers backed up against a back support wall. If you look at the 2 plots, the smoothing is obviously different; but there is still the same dip in the second dyno around the same rpms. It still drops a good 5 hp like the first one. I still believe that this has to do with airflow problems on the dyno as no fans were used to help provide airflow to the engine on any of the runs. I agree there there are some fluxuations from dyno to dyno and day to day, but this will account for a very small amount of error (1-2%). This difference should be minimized from the SAE corrected results.

10 GT3

Would you like to explain what the Alpha values are and what they do? You should give a call to GIAC, Powerchip or Jim Wolf Technology if you don't know or understand what they are.

1999Porsche911

You make a mod, you reset computer. At WOT, ECU is looking at his MAF reading primarily, not O2 sensors, fuel trims, etc. Timing, etc, responds to MAF reading, engine and intake temps immediately. Like I said, no learning curve for WOT.

ianwallwork

I understand there is a correction for MAF 'scaling' - in other words how the MAF output varies with flow. Some can be dead accurate at low flow but get wider of the mark at high flow, others the exact opposite. As far as I'm aware, this is calculated by the DME from the lambda corrections required at varying flows and finally extrapolated to WOT and other higher throtle openings once enough data has been acquired. This also explains why some K&N users don't get a CEL for many miles.

Ian W

1999Porsche911

At WOT, the O2 sensor readings are not even a factor. Learning is for closed loop operation only (other than knock). The learning consists of finding the proper balance for the fuel trim for startup and cruising. Again, this has nothing to do with performance at WOT. Disconnect your o2 sensors at WOT and your performance will be unchanged.

rountreed

Thanks for placing this here! I am still on the fence about the K&N upgrade based upon what I am reading but it sounds like you got your moneys worth out of these upgrades!

JimB

Are you sure? I'm no expert but don't your O2s control air/fuel. Wouldn't that be a primary area of adjustment when adding intake and exhaust mods?

Ubermensch

What 1999Porsche911 stated is correct. At WOT O2 sensors do not play a role. Fueling is based strictly on a predetermined map. O2 sensors are used during closed loop operation to achieve optimum fuel efficiency/emissions characteristics.