Why yes it is me. That pic. was taken at the NBL grands in KY. I have raced all over but have never been to that track in NJ. I don't know how old you are but, these days a lot of people in their mid 30's who used to race in the 80's are back into it.

 

How do you then explain Synergy's 27 bhp gain with no internal mods? That wasn't measured by a butt dyno.

 

If I had to guess, I'd say they could do it with very good bolt-on parts and the following:

1. Good qality fuel (93+ octane)
2. Nice COOL day (better yet, a winter morning)
3. Re-flashed chip with higher rpm limit

That might do it but with some risk with the higher rpm limit.

MC

 

Fair question.

First I did not say no gain. I'll leave room for the right set of parts to cause some gain.

Second, that 296 reading is a little low for a 3.8L "S" motor. I'm not saying it didn't happen, but "S" motors generally turn 10-14 more WHP than that particular one.

Third, I didn't see multiple pull data. One can easily get a 3-5 WHP deviation from one pull to the next. So, statistically speaking, considering range and SD's, the gains as reported are subject to possibly being somewhat greater than reported to being a lot less.

Now consider that he likely spent $7-10K on all that. Further, I'll bet $1000 to any taker here that an X-51 will pull numbers that make his gains look much smaller.

Finally, read his subjective comments. I commend him greatly for them. Whether he pulled 5 or 35 more WHP, he feels like the real delta is kinda small. As I would expect from a less-than-10% increment.

In the real world I can tell you that unless you're pulling 25% more WHP, it's just not that much faster. And as I said before, it gets slow fast. And before you know it you need a bigger fix.

 

3.8L will pull about 303hp

 

Fair enough. I've heard 305-310. One I heard of pulled 312. Again, with this a complex circumstance, deviation is significant.

Either way there goes about 25% of Synergy's gain vs. your experience.

 

i pulled 312 on a very cold car..but repeated between 300-305

 

Age old discussion on car boards. I pretty much agree with allegretto's school of thought, but I'll throw in one other thing. I don't believe most tuner dynos are really very good at getting to the truth. There is the issue of bias, lack of reproducibility over multiple runs, and a general lack of adequate controls to detect relatively small differences. Even more important is the issue of whether an A:B dyno comparison can be extrapolated to real world performance.

Most manufacturers use a very expensive dyno set-up that is almost like a wind-tunnel. This creates a huge airflow to mimic the changes in intake charge as the car is in motion. Most tuner dynos are insufficient in that regard. They can indicate a dyno improvement that actually translates to a real world power loss. Unless dyno tests are done under VERY rigorous conditions I would actually rather see controlled performance data, whether 0-60 or 1/4 mile times.

The best online write-up of this stuff that I have seen is by Steve Dinan, BMW tuner. It should be mandatory reading for anyone arguing dyno results.

http://www.dinancars.com/whitepapersFile.asp?ID=9

 

good read - too many problems with dynoing - anyone here with a stock s wanna race ?

 

CAF-

I've read that.

I would like you to read ours as well.
http://awe-tuning.com/pages/faq/awefaq_main.cfm?FAQ=22

 

I would agree with pretty much everything in your write-up, but you don't address the problem of getting adequate, realistic airflow at the front of the car. I think that's a BIG omission in most dyno testing, and the one most likely to result in deceiving results when trying to apply dyno results to real world performance. It also means you can't really trust A:B before and after testing, especially with ECU mods.

 

Also don't forget that many of these exhaust systems are not 50 state legal or unproven. Sure I wouldn't mind pay 70% less for the same amount of power increase (if it works) but more importantly, will I have to strip it down everytime a smog check comes along? I haven't seen one manufacturer say 50 state smog legal. I happen to know that the cat is one of the clog links in an exhaust system and having hiflow cats or straightpipes removes this bottleneck, hence you get more gains than with a cat.

 

There is no way we are going to fix the Dyno variation problem here. The question isn't what is the absolute HP (as this would require some type of known standard with which to calibrate all dynos), the question is can we replicate the same test conditions such that the variation in test is minimized so we get the DELTA. The DELTA is all we care about. How much did the mods get you (probably on average which will help to minimize the measurement system error)? That is the question and the answer to how tuners can make specific claims (not just on a small sample run under their ideal conditions).

 

Believe me, you are preaching to the choir. We have invested thousand of dollars and spent years trying to find the best way to move more air. This is something that every dyno operator struggles with. The only thing you can do is adjust your testing accordingly.

Even Dinan can't get adequate airlflow. This is a quote from this article regarding what they use:

"actually designed for ventilation systems installed in high rise buildings!"

"This powerful fan produces 38,000 cfm of air flow @ 75 MPH, which is still less than the 150 MPH air that a modern BMW might see at redline in 5th gear, but it certainly provides a closer to real-world scenario than the more common fans I have seen used in dyno facilities."

Like I said before. This is not something new to us. We have had several dyno shops calling us for advice becuase we are known throughout the industry as a leader in airflow research.

 

To All

I am glad to see that this thread has initiated a vigorous discussion about the issue of reasonably priced performance modifications to the 997S. Aside from the half-assed comedians waxing their cars for more speed, most of the responses were germane to the topic and often informative. They served the true purpose of this forum, which is to share information and learn about our cars.

I think that the issues raised cannot be finally resolved without comparative and scientifically conducted dynamometer testing of a variety of aftermarket products. This would most likely require participation and funding by a group of aftermarket producers and/or a major Porsche enthusiast publication. Mike @ AWE's offer is commendable and exposes their company to risk they do not do not have to assume. Is anyone else willing to step up to the plate? Proven dynamometer horsepower is much more impressive than horsepower at the brochure.

A final question, is it worth it? Thousands of dollars for what? The only answer I can give is that there is no reasonable cost methodology for attaining moderate power improvements to the 997S other than exhaust, intake and ECU reflashing. It is the only game in town.

Regards

Mike