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-   -   VF engineering tune (https://rennlist.com/forums/997-forum/1120887-vf-engineering-tune.html)

bgoetz 01-19-2019 09:26 AM


Originally Posted by Appraiser (Post 15576936)
Not sure where the $700 came from...?

My anecdote was to highlight the point that it took several thousand to get a "meaningful" performance increase out of that Honda F20. I'd have to dig out the dyno sheet to see what the stock number was, I want to say 204-ish. In my experience it wasn't as simple as a few hundred flash for 220 whp and all was good. I would expect the same or more for high caliber cars such as the Boxster or 911. I'm sure you get what I mean when I say meaningful (material delta at all rpms used).

I'm in the camp that believes Porsche wouldn't have left meaningful power on the table if the cost/benefit didn't support it. I dunno if I buy the emissions arguments; gearing, ancillary components for startup/temperature, filters, etc. play more to that than engine tuning in my completely uneducated opinion.

A meaningful 10 whp increase across the usable power band is hard to find on relatively modern naturally aspirated cars with aftermarket parts. And there's plenty of Boxster race cars out there every weekend trying to find it!


If you have an 06+ S2k the tune is as simple as a flash and costs around $700. I think lots of them result in around 220whp or 10whp gain. The flash is basically what the tune is for the 997, likely similar gains at a similar cost, which IMO is worthwhile given you can spend 2x on an intake for this car and it changes very little in terms of power.

vern1 01-19-2019 12:13 PM

For 10HP why bother? Maybe it makes a noticeable difference on a car with 200hp but no one is ever going to notice 10hp on a 355hp car. Feel the same way about the intakes as well btw

For real noticeable improvement you have to go FI or boring etc and that comes with a material cost

bgoetz 01-19-2019 12:49 PM


Originally Posted by vern1 (Post 15577703)
For 10HP why bother? Maybe it makes a noticeable difference on a car with 200hp but no one is ever going to notice 10hp on a 355hp car. Feel the same way about the intakes as well btw

For real noticeable improvement you have to go FI or boring etc and that comes with a material cost

Whp, so a stock 997 C2S probably makes 300whp and weighs 3,100 lbs, so ~10.3lb/hp. At 310whp that # goes to 10lb/hp, essentially like removing 100lbs from the car, which I notice an extra 100lbs of weight in my C2S in terms of acceleration. Now it isn’t the peak whp but the gains throughout the power curve that make it really noticeable (the 20+ whp graph in this gap).


https://cimg3.ibsrv.net/gimg/rennlis...6507e25ce.jpeg

Milo2361 01-19-2019 12:58 PM


Originally Posted by bgoetz (Post 15577783)


Whp, so a stock 997 C2S probably makes 300whp and weighs 3,100 lbs, so ~10.3lb/hp. At 310whp that # goes to 10lb/hp, essentially like removing 100lbs from the car, which I notice an extra 100lbs of weight in my C2S in terms of acceleration. Now it isn’t the peak whp but the gains throughout the power curve that make it really noticeable (the 20+ whp graph in this gap).


https://cimg3.ibsrv.net/gimg/rennlis...6507e25ce.jpeg


cant zoom in legibly on the graph, but how does one get rid of that dip that looks like its around 5200rpm (both HP and Tq)? I've seen it on nearly EVERY dyno sheet for a naturally aspirated 997, and while I could kind of feel it when my car was stock, once I did full exhaust and intake after the rebuild, the dip is really pronounced at WOT. pretty much non existent when I'm not flooring it, but its annoying and it shouldn't be there.

bgoetz 01-19-2019 01:28 PM

Try this:

https://www.fabspeed.com/porsche-997...peed-ecu-tune/

it is just a dyno from Fabspeeds website. Looks like the dip is still there, the hp is just bumped up a touch.


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