hausherrs

Whats up! I will have a new set of X51 headers this Wednesday and will have them installed before bed time. Tomorrow I am taking the car to the dyno to have a baseline done. So I will be able to show a before and after. The only mod I have that will affect the WHP/TQ will be the Aasco flywheel. Other then that everything is stock with PSE.

I will probably remove the stock headers tomorrow evening and have it all cleaned up and ready for the new on Wednesday.

Would any one mind sharing the bolt tq specs?

Thanks!!

Steven <-- excited I get to tear something up tomorrow...

Dave07997S

Looking forward to you reporting back...

alexb76

EXCELLENT. Looking forward to reviewing the numbers. You can probably quanify all the claims about X51 headers. Make sure the tempreture is as close in both runs, and try to repeat as close of a setup as you can!

Cheers!

Edgy01

Take a look at my postings from a couple of years ago. Worth noting before you get into it.

https://rennlist.com/forums/997-foru...-awe-cats.html

https://rennlist.com/forums/997-foru...we-cats-2.html

Para82

Very interested in your install, especially how your exhaust sound with PSE turns out...

Edgy01

Exhaust manifold M8x28Tightening torque 17 ftlb

hausherrs

Interesting... Much higher then I expected. Temp was 58, Sport OFF, driven 45 minutes prior to dyno.

SAE HP - 329.7@6700 & TQ - 278.7@4700
STD HP - 344.7@6700 & TQ - 291.4@4650

Thoughts??

Headers go on tomorrow then I will run it again.

Steven

hausherrs

STD chart

alexb76

Nice!!! Relatively flat Torque curve between 3000 to 6500 looks great... totally different than my Tubro car! gotto love the flat-6!

Can't wait to see the next dyno result to see how and if it changes.

Dave07997S

Numbers definitely look high but as long as you use the same dyno and give the car some time to adapt to the mod you will get a good idea if there was any gain.

Putting the headers on the car and dynoing right after the mod is complete will not give you an accurate reading in my opinion.

You need to let things adapt for at least 100 miles and then go back and dyno.

You can speed the process somewhat by resetting the DME and then drive around with a couple of good WOT passes to redline to let the DME re-learn the airflow changes.

Dave

hausherrs

I plan to do the install this evening and it will probably be next week some time before I can make it back there. Luckily the shop is about 2 miles from my house so I can just stop on the way home.

Question, how do you reset the DME? Also, considering that there are no visible mods on the engine I would almost have to assume that the ECU has been flashed to get numbers like that on the dyno. How would I go about finding out if its been flashed?? As I said before, the only thing I know of that would affect the dyno numbers would be the flywheel but I cant see it freeing up 30 hp. I have the working log with DME info. Has all kinds of software revision numbers etc.

Thanks in advance!

Steven

RonCT

Everything I've read over the years regarding dyno is that unless you do them back-to-back with multiple pulls (ie: 3 before, immediately swap, 3 after) the numbers won't really mean anything. Reasons given were ambient temperature, humidity, etc. I guess it all has an impact on power.

Dave07997S

Ron they usually can adjust for atmospheric changes when the info is put into the dyno such as all the variables you showed. Doing a dyno run right after the install will skew results as the maps will not be adjusted to the airflow (if any) changes. Remember the arguments or debates during the old roadfly days..

I miss those days..

Dave

Dave07997S

Steven a LWFW can usually free up 10-12rwhp so if your SAE numbers are 329 subtract 12rwhp that would put us at 317rwhp...that is definitely attainable on a strong 997S on good fuel.

Dave

RonCT

Long live the old RoadFlea debates! I can see a tuning shop that designs products (like AWE, Fabspeed, etc.) having well-tuned dynos with weather station equipment to equalize for conditions. Even then I'd wonder with a single pull one day and a single one a week later.

I've never done a dyno because whether it says 1 HP or 10, it doesn't matter to me. I'm not trying to justify a $ / HP. I'm interested in the science and practical experience. 9 out of 10 racers find X to work better than stock and if the science agrees, I'll try it. I'll see from my TraqMate whether there's any difference, however subtle.