RSS Plenum
#31
You haven't done your homework. There has been near universal praise of this mod. Ian has recently raised an as yet unanswered question: why didn't it feel good to me? I hope he adds closure to that thread and does not leave it unresolved to confuse folks like you who come later. Then there has been lardas...er...larddog, who seems to enjoy negative attention and has no experience w the plenum but knows how to bust'em. Please do a search and read the results. As I said, to my knowledge all who have installed it have liked it with the possible exception of Ian who should address his "deplenum" post in all fairness to the product and it's potential users.
#33
I too am anxious (and hopeful) to see the dyno results. As to the "near universal praise", those have all been totally seat-of-the-pants and could be easily attributed to the Hawthorne effect. If you recall, a few months ago, the majority of folks were clamoring for more scientific (and independent) proof, but one by one they settled for the butt dyno. I too, agree that the design of the OEM plenum looks sub-optimal, however 27 bhp seems hard to believe. BTW, even if it's half of the claimed increase it will be a cost effective mod in comparison to other alternatives.
We'll soon see. I'm also curious to see florindi's results because his "dyno after a week" approach seems to allow time for the ECU to recalibrate. [AWE: are you putting the requisite 50 miles on in between?]
We'll soon see. I'm also curious to see florindi's results because his "dyno after a week" approach seems to allow time for the ECU to recalibrate. [AWE: are you putting the requisite 50 miles on in between?]
Last edited by RickinColorado; 04-17-2008 at 03:34 PM.
#34
There is a lot of misinformation out there regarding modern Bosch fuel injection and adaptation routines.
Full throttle adaptation on the street can take a while to happen, simply because it is hard to do repeated full rpm WOT acceleration runs on the street.
However, it is very easy to do full throttle adaptation on the dyno, since you can do full throttle pulls all day long. Exposing the fuel injection ECU to full throttle operating conditions in such a condensed manner results in very quick setting of full throttle adaptation.
Usually we see power curves stabilize within 4-5 dyno runs on most cars after a part change. Proper care must be taken to ensure that the engine is not being overheated, as that will cause the ECU to take protection measures and pull back ignition timing or enrichen fueling, which will corrupt results.
What does take several miles of driving to ensure full adaptation is part throttle mapping. This is because of the multitude of loads that the car sees at part throttle. Driving on a level surface in 4th gear at a fixed rpm takes different mapping than the same rpm and gear going up a hill. All these variables are accounted for after many miles of driving, allowing the ECU to "tune in" on what your engine needs for all these different operating conditions.
Yet, the full throttle environment has far fewer variables to account for, which is why full throttle adaptation can be done so quickly on the dyno. Full throttle maps are much different and less numerous than part throttle maps.
Full throttle adaptation on the street can take a while to happen, simply because it is hard to do repeated full rpm WOT acceleration runs on the street.
However, it is very easy to do full throttle adaptation on the dyno, since you can do full throttle pulls all day long. Exposing the fuel injection ECU to full throttle operating conditions in such a condensed manner results in very quick setting of full throttle adaptation.
Usually we see power curves stabilize within 4-5 dyno runs on most cars after a part change. Proper care must be taken to ensure that the engine is not being overheated, as that will cause the ECU to take protection measures and pull back ignition timing or enrichen fueling, which will corrupt results.
What does take several miles of driving to ensure full adaptation is part throttle mapping. This is because of the multitude of loads that the car sees at part throttle. Driving on a level surface in 4th gear at a fixed rpm takes different mapping than the same rpm and gear going up a hill. All these variables are accounted for after many miles of driving, allowing the ECU to "tune in" on what your engine needs for all these different operating conditions.
Yet, the full throttle environment has far fewer variables to account for, which is why full throttle adaptation can be done so quickly on the dyno. Full throttle maps are much different and less numerous than part throttle maps.
#35
Guys,
This is a *very* hot topic, and we are making sure a 100% fair test is conducted. The last thing we want to do is provide false data, whether good or bad.
We're wrapping up our testing today and I will then attempt to present a detailed and thorough synopsis of our findings. Please forgive me if the presentation does not happen until tomorrow, as it is somewhat late in the day here already.
We appreciate your faith in us to provide you with unbiased results, and we do not take that trust lightly.
This is a *very* hot topic, and we are making sure a 100% fair test is conducted. The last thing we want to do is provide false data, whether good or bad.
We're wrapping up our testing today and I will then attempt to present a detailed and thorough synopsis of our findings. Please forgive me if the presentation does not happen until tomorrow, as it is somewhat late in the day here already.
We appreciate your faith in us to provide you with unbiased results, and we do not take that trust lightly.
#36
Why does it seem that only peak numbers matter to everyone? If it only gains 2whp peak but 15whp across the midrange that would be significant imho.
#37
If the car is rated @ 355 factory hp and the mods do not improve it, or only by a few hp, it's of no interest to me.
#38
This was my post that referred to the results obtained over at Rennlist - no confusion whatsoever....
"..... I've not seen any independent dynos of the plenum on its own so I've no idea what to expect! Seems there are one or two cynics on here that are expecting a sensational zero however.....
One of the members on Rennlist had before and after dynos done on a full 997S AWE system last year and it produced a creditable 23BHP increase at the wheels - about 28BHP crank - not bad at all......"
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"..... I've not seen any independent dynos of the plenum on its own so I've no idea what to expect! Seems there are one or two cynics on here that are expecting a sensational zero however.....
One of the members on Rennlist had before and after dynos done on a full 997S AWE system last year and it produced a creditable 23BHP increase at the wheels - about 28BHP crank - not bad at all......"
__________________
Last edited by Ian_UK1; 04-17-2008 at 04:29 PM.
#39
Why is this of no interest?
#40
This was my post that refered to the results obtained over at Rennlist - no confusion whatsoever....
"..... I've not seen any independent dynos of the plenum on its own so I've no idea what to expect! Seems there are one or two cynics on here that are expecting a sensational zero however.....
One of the members on Rennlist had before and after dynos done on a full 997S AWE system last year and it produced a creditable 23BHP increase at the wheels - about 28BHP crank - not bad at all......"
__________________
"..... I've not seen any independent dynos of the plenum on its own so I've no idea what to expect! Seems there are one or two cynics on here that are expecting a sensational zero however.....
One of the members on Rennlist had before and after dynos done on a full 997S AWE system last year and it produced a creditable 23BHP increase at the wheels - about 28BHP crank - not bad at all......"
__________________
#41
My example above wasn't supposed to refer to the plenum - just a thought experiment for you. If you hit the throttle at 3000rpm and your car pulls way harder than stock but by 7000rpm it only pulls the same, then you have a much faster car with nominally the same BHP. It's all about area under the curve.... but that's another discussion for when I've had some sleep. It's gettin' late over here!!
#42
If a mod gives you a shed-load of extra mid-band torque but the same top end power (hence top speed too) then you have a vastly improved car. Under most give and take, day to day driving conditions it will easily out-accelerate the standard car.
Why is this of no interest?
Why is this of no interest?
I also thinks it's very misleading when a companies state say a +30hp gain in power (without disclosing exactly where the gain is) when the engine itself still turns out the same or a fractionally better # over the factory max power.
Last edited by 500; 04-17-2008 at 04:38 PM.
#43
Not to sound like an a$$ or anything, but you should do some research by running a few searches. I would be stunned if the results showed an increase of 5-10whp peak or for that matter across the rev range.
#44
Because of there is no true gain in overall/max/.peak power it's of no interest to me. Peak power also affects much more than top speed. Plus there are plenty of mods out there especially for forced induction cars that greatly improve max power.
I also thinks it's very misleading when a companies state say a +30hp gain in power when the engine itself still turn out the same or a fractionally better # over the factory max power.
I also thinks it's very misleading when a companies state say a +30hp gain in power when the engine itself still turn out the same or a fractionally better # over the factory max power.
#45
Because of there is no true gain in overall/max/.peak power it's of no interest to me. Peak power also affects much more than top speed. Plus there are plenty of mods out there especially for forced induction cars that greatly improve max power.
I also thinks it's very misleading when a companies state say a +30hp gain in power when the engine itself still turn out the same or a fractionally better # over the factory max power.
I also thinks it's very misleading when a companies state say a +30hp gain in power when the engine itself still turn out the same or a fractionally better # over the factory max power.