Nov 1, 2009 8:34:33 PM
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porschephile1
- Junior
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- Loc: Texas , United States
- Posts: 65, Gallery
- Registered on: Apr 23, 2009
- Reply to: STRADALE
Re: The result of IPD Plenum + Exhaust
Porschephile - Did I understand this correctly; this was referring to the difference of just the IPD plenum - "The overall improvement for my car across the whole power band is roughly 4-5%. At my level that is roughly 25 hp"
Stradale,
The graph above shows the effect of a 75mm IPD plenum and a 75mm throttle body added to a 996TT that previously was modded with EVOMS GT700 kit. The 4-5% improvement is an average increase in g forces measured on the performance box and calculated with their software. This data was run in July when my car had about 580 whp. Thus 4-5% of that would be roughly 25 whp. The graph shows only the effect of the plenum and throttle body. I believe it is more or less congruent with prior claims about the plenum.
Here are some more data I collected at the time I installed plenum/TB This is a 60-100 or so with very similar atmospheric conditions. The blue line is GT700 alone and the red line is GT700+ plenum. The software is a little goofy and wont let me superimpose the runs exactly but if you look closely you can see that the plenum line starts at a lower speed but then accelerates past the non-plenum line. The green line is linear acceleration in gs of the plenum. The black line is linear acceleration of the non-plenum.
Next I have a 60-130 mph done entirely in fourth gear to remove the variable of shifting. Again atmospheric conditions were as similar as possible. (Once summer hits in south Texas every day is almost identical to others ie hot and humid!!). Again, the plenum is the red line and the nonplenum is the blue line. The software again wont let me line the runs up perfectly, but you can see the red line starts at slightly a lower speed and then passes the blue line by 130 mph (and keeps pulling away even above 130). You can see the pattern I described earlier here as well. The red line catches up to the blue line fairly early in the run then holds relatively even then pushes significantly ahead in the higher rpms. The actual time of the 60-130 runs was 7.37s for the plenum and 7.53s without the plenum/TB. Remember, this is a fourth gear ,no shift, run in heat and humidity.
In these last two graphs, the gains of the plenum are less. More along the lines of 2-3%. But you can still see the pattern in both graphs with greater power immediately after the turbos hit then laying back abit and finally a harder pull to the redline at the top.
