THE PLENUM "friendly Chapter 2"

[porschester]

Hi once again everyone.......and.... :welcome: I am RE-opening the topic to anyone that could educate US on the "PLENUM". We all may have different opinions about what we think of the PLENUM but the goal should be to assess and figure out if it is a Modification worth our effort and money, while safe enough to to keep the reliability and integrity of our Porsches. It has been a hot topic lately and few people have posted their opinion on 6speedonline. As RennTech subscribers who like to come to this forum to learn, share and interact between us, lets build on this topic so that we could get to the bottom of it, and reach a balanced verdict of what the PLENUM can or can not achieve in our "bottom line" search for additional horses. What could we, us, owners of 997 and 997S realistically expect from the RSS PLENUM once we put the $995 for the relatively small iron cast piece. The company Roadsportsupply.com which I talked to, claims 24HP/22TQ on the 997 and 27HP/25TQ on the 997 S. If indeed anyone has seen and felt that kind of difference before and after the PLENUM was installed beyond the benefit of the doubt I certainly will put one. Others put the increase more in the 10-11HP. During my telephone conversation with Roadsportsupply they even claimed that their figures were conservative!!! Lets make Renntech, the premier forum for the PLENUM debate. If we conclude it is worth it, it could be Bang for Dollar, one of the best and easiest mod add on yet.

I am including the link that states the HP/TQ increase of the different PLENUMS:

http://roadsportsupply.com/IPD_Plenums_Porsche.html

Thanks in advance for sharing any mentoring, and advice. :lightbulb:

Cheers :renntech:

Porschester :thumbup:

Edited October 1, 2007 by porschester

[dndodd]

Hi once again everyone.......and.... :welcome: I am RE-opening the topic to anyone that could educate US on the "PLENUM". We all may have different opinions about what we think of the PLENUM but the goal should be to assess and figure out if it is a Modification worth our effort and money, while safe enough to to keep the reliability and integrity of our Porsches. It has been a hot topic lately and few people have posted their opinion on 6speedonline. As RennTech subscribers who like to come to this forum to learn, share and interact between us, lets build on this topic so that we could get to the bottom of it, and reach a balanced verdict of what the PLENUM can or can not achieve in our "bottom line" search for additional horses. What could we, us, owners of 997 and 997S realistically expect from the RSS PLENUM once we put the $995 for the relatively small iron cast piece. The company Roadsportsupply.com which I talked to, claims 24HP/22TQ on the 997 and 27HP/25TQ on the 997 S. If indeed anyone has seen and felt that kind of difference before and after the PLENUM was installed beyond the benefit of the doubt I certainly will put one. Others put the increase more in the 10-11HP. During my telephone conversation with Roadsportsupply they even claimed that their figures were conservative!!! Lets make Renntech, the premier forum for the PLENUM debate. If we conclude it is worth it, it could be Bang for Dollar, one of the best and easiest mod add on yet.

I am including the link that states the HP/TQ increase of the different PLENUMS:

http://roadsportsupply.com/IPD_Plenums_Porsche.html

Thanks in advance for sharing any mentoring, and advice. :lightbulb:

Cheers :renntech:

Porschester :thumbup:

in case the PM didn't work try this;

http://www.6speedonline.com/forums/showthread.php?t=75107

[Dave07997S]

Hi once again everyone.......and.... :welcome: I am RE-opening the topic to anyone that could educate US on the "PLENUM". We all may have different opinions about what we think of the PLENUM but the goal should be to assess and figure out if it is a Modification worth our effort and money, while safe enough to to keep the reliability and integrity of our Porsches. It has been a hot topic lately and few people have posted their opinion on 6speedonline. As RennTech subscribers who like to come to this forum to learn, share and interact between us, lets build on this topic so that we could get to the bottom of it, and reach a balanced verdict of what the PLENUM can or can not achieve in our "bottom line" search for additional horses. What could we, us, owners of 997 and 997S realistically expect from the RSS PLENUM once we put the $995 for the relatively small iron cast piece. The company Roadsportsupply.com which I talked to, claims 24HP/22TQ on the 997 and 27HP/25TQ on the 997 S. If indeed anyone has seen and felt that kind of difference before and after the PLENUM was installed beyond the benefit of the doubt I certainly will put one. Others put the increase more in the 10-11HP. During my telephone conversation with Roadsportsupply they even claimed that their figures were conservative!!! Lets make Renntech, the premier forum for the PLENUM debate. If we conclude it is worth it, it could be Bang for Dollar, one of the best and easiest mod add on yet.

I am including the link that states the HP/TQ increase of the different PLENUMS:

http://roadsportsupply.com/IPD_Plenums_Porsche.html

Thanks in advance for sharing any mentoring, and advice. :lightbulb:

Cheers :renntech:

Porschester :thumbup:

There were actually a couple of dyno's posted for a 3.6 not the 3.8L S motor. The 3.6L motor made 10rwhp at the peak, and 23rwhp more at it's widest delta..so RSS seems to be quoting the most amount of hp increase within it's rpm range. At the peak it seems they are worth about 10rwhp according to what I have seen. Than again I know someone who got it and took it off his car and "gave" it to someone...he felt it was worth zip...

If you look at RSS's dyno sheets given on the 6speed thread you can see that it made a little more than 11rwhp at it's peak.

Dave

Edited October 1, 2007 by Dave07997S

[porschester]

Thanks Dave for your input......If we saw an effective 10rwhp increase with the 3.6L, can we assume that increase in rwhp with my 3.8L 997S would be more?...Also dave do you think that adding the Plenum to current mods I already have (TUBI, X51 intake and GIAC) will bring a difference and improvment in acceleration??

Cheers

Porschester

[phillipj]

Thanks Dave for your input......If we saw an effective 10rwhp increase with the 3.6L, can we assume that increase in rwhp with my 3.8L 997S would be more?...Also dave do you think that adding the Plenum to current mods I already have (TUBI, X51 intake and GIAC) will bring a difference and improvment in acceleration??

Cheers

Porschester

Just wanted to put my experience here. I just installed one last week on my 3.4 996. There is a noticable improvement in power from 4500 to 6500 rpm. I have no idea what 10 hp compared to 20 hp feels like.

I'm very happy I made the mod. I would no way put the stock one back on. I have the GIAC chip, Fabspeed intake and Fabspeed mufflers.

I mentioned in a previous post, if anyone is going to install one I can give them some simple tips to make the job much easier.

Glad we can have a good discussion on this topic.

Phillipj

Edited October 1, 2007 by phillipj

[porschester]

Hi Phillipj....Thanks for sharing with me your experience with the Plenum. It seems like you are quite happy, and felt the difference. After giving much thinking about it, I decided to go ahead and order myself one via the Porsche dealer, they extended the price of $816...definitely less than the $995 advertised on the RSS site. So your 996 since installing the Plenum has performed and felt a little better at 4500-6500 rpm?? No engine light?? or loss of low end torque or anything like that...!! You can confirm that the money you spent was worth the change???

Was it the RSS plenum you installed or another one??

Thanks Again for your feedback

Cheers

Porschester

[phillipj]

Hi Phillipj....Thanks for sharing with me your experience with the Plenum. It seems like you are quite happy, and felt the difference. After giving much thinking about it, I decided to go ahead and order myself one via the Porsche dealer, they extended the price of $816...definitely less than the $995 advertised on the RSS site. So your 996 since installing the Plenum has performed and felt a little better at 4500-6500 rpm?? No engine light?? or loss of low end torque or anything like that...!! You can confirm that the money you spent was worth the change???

Was it the RSS plenum you installed or another one??

Thanks Again for your feedback

Cheers

Porschester

Porshester,

Just to go over your questions. No CEL (it has nothing to do with electronics and is after the MAS so it wouldn't trigger one.) No loss of Torque. The power band is the same just with more grunt. I really love it. I bought mine from Chuck Jones here on Renntech. He had a fire which totalled his car and he sold the mods he had done. That price from Porsche is good! Is it an RSS? Mine is the RSS.

I have had mine on for two weeks now. Just today I went on one of my favorite on - ramps and was really impressed by the difference. It's really quick.

I raced a couple of young guys in a new 997 4S the other day. They barely were able to pull me. The driver had a pasenger and I was alone. He pulled up to me when we came to a stop and said. "WHAT DID YOU DO TO THAT THING?" Sweet... Worth every penny.

Are you going to install it yourself? It's a pretty easy job. I can tell you one tip that will make the job even easier if you are. Let me know. You can PM me and I'll give you my cell number.

Hope this helps. I have no bias on this. If it didn't make a difference I would let you know.

I'm sure your S with your current mods is really quick already. This mod should bring a smile to your face. Maybe try to do some rough 0 to 100 times before you install the plenum. Then do them again after the install.

Take care and let me know if I can be of help.

Phillipj

Phillipj

Edited October 2, 2007 by phillipj

[CoreyNJ]

Just to add to the topic. Also a disclaimer I have no association to RSS, I just do a lot of research before I go with anything on my car non-porsche.

The Plenum is a part that is changed on the power kit by porsche, though not to as engineered a device as the RSS piece. So on a powerkit car, the gains would be minimal. On a non-power kit car with the simple plastic T, there are areas of the RPM range where turbulance causes some hesitation in acceleration/deceleration. The molded shape of the RSS piece smooths those out so that it feels like a compeltey different car.

As for HP gains, their are some gains, but it took RSS nearly 2 years to bench flow this solution out. It wouldn't make much sense for Porsche to spend their time going after 1 part to "maybe" get a small HP gain, but to attack all the percieved HP "bottlenecks" in the car at once and to do them in the most cost effective manner. So the powerkit gets dual intake, smoothed out plenum design (not as advances as RSS), smoothed out intake runners, header/exhaust modification, minor engine tweeks and computer changes that would guarantee porsche is able to make it's power goals.... 1hp more than the 996 GT3.

[phillipj]

Just to add to the topic. Also a disclaimer I have no association to RSS, I just do a lot of research before I go with anything on my car non-porsche.

The Plenum is a part that is changed on the power kit by porsche, though not to as engineered a device as the RSS piece. So on a powerkit car, the gains would be minimal. On a non-power kit car with the simple plastic T, there are areas of the RPM range where turbulance causes some hesitation in acceleration/deceleration. The molded shape of the RSS piece smooths those out so that it feels like a compeltey different car.

As for HP gains, their are some gains, but it took RSS nearly 2 years to bench flow this solution out. It wouldn't make much sense for Porsche to spend their time going after 1 part to "maybe" get a small HP gain, but to attack all the percieved HP "bottlenecks" in the car at once and to do them in the most cost effective manner. So the powerkit gets dual intake, smoothed out plenum design (not as advances as RSS), smoothed out intake runners, header/exhaust modification, minor engine tweeks and computer changes that would guarantee porsche is able to make it's power goals.... 1hp more than the 996 GT3.

CoreyNJ,

Great information. Thanks!

Phillipj

[Dave07997S]

Just to add to the topic. Also a disclaimer I have no association to RSS, I just do a lot of research before I go with anything on my car non-porsche.

The Plenum is a part that is changed on the power kit by porsche, though not to as engineered a device as the RSS piece. So on a powerkit car, the gains would be minimal. On a non-power kit car with the simple plastic T, there are areas of the RPM range where turbulance causes some hesitation in acceleration/deceleration. The molded shape of the RSS piece smooths those out so that it feels like a compeltey different car.

As for HP gains, their are some gains, but it took RSS nearly 2 years to bench flow this solution out. It wouldn't make much sense for Porsche to spend their time going after 1 part to "maybe" get a small HP gain, but to attack all the percieved HP "bottlenecks" in the car at once and to do them in the most cost effective manner. So the powerkit gets dual intake, smoothed out plenum design (not as advances as RSS), smoothed out intake runners, header/exhaust modification, minor engine tweeks and computer changes that would guarantee porsche is able to make it's power goals.... 1hp more than the 996 GT3.

Actually Coryey I think they only change the plenum on the X51 cars as the intake manifolds have a different opening to them and it is to accomodate this. The plenum is changed but just for that purpose, it is still the basic design as the non X51 part.

If the RSS plenum works it would probably work even better with the x51 with the intake, throttle body and not to mention the cleaned up heads the X51 has along with the better exhaust manifolds.

Dave

[CoreyNJ]

Just to add to the topic. Also a disclaimer I have no association to RSS, I just do a lot of research before I go with anything on my car non-porsche.

The Plenum is a part that is changed on the power kit by porsche, though not to as engineered a device as the RSS piece. So on a powerkit car, the gains would be minimal. On a non-power kit car with the simple plastic T, there are areas of the RPM range where turbulance causes some hesitation in acceleration/deceleration. The molded shape of the RSS piece smooths those out so that it feels like a compeltey different car.

As for HP gains, their are some gains, but it took RSS nearly 2 years to bench flow this solution out. It wouldn't make much sense for Porsche to spend their time going after 1 part to "maybe" get a small HP gain, but to attack all the percieved HP "bottlenecks" in the car at once and to do them in the most cost effective manner. So the powerkit gets dual intake, smoothed out plenum design (not as advances as RSS), smoothed out intake runners, header/exhaust modification, minor engine tweeks and computer changes that would guarantee porsche is able to make it's power goals.... 1hp more than the 996 GT3.

Actually Coryey I think they only change the plenum on the X51 cars as the intake manifolds have a different opening to them and it is to accomodate this. The plenum is changed but just for that purpose, it is still the basic design as the non X51 part.

If the RSS plenum works it would probably work even better with the x51 with the intake, throttle body and not to mention the cleaned up heads the X51 has along with the better exhaust manifolds.

Dave

It's a very different cast part, not a plastic part like the non powerkit models, atleast on the 996 it's not.

Edited October 3, 2007 by CoreyNJ

[cgng30]

Just to add to the topic. Also a disclaimer I have no association to RSS, I just do a lot of research before I go with anything on my car non-porsche.

The Plenum is a part that is changed on the power kit by porsche, though not to as engineered a device as the RSS piece. So on a powerkit car, the gains would be minimal. On a non-power kit car with the simple plastic T, there are areas of the RPM range where turbulance causes some hesitation in acceleration/deceleration. The molded shape of the RSS piece smooths those out so that it feels like a compeltey different car.

As for HP gains, their are some gains, but it took RSS nearly 2 years to bench flow this solution out. It wouldn't make much sense for Porsche to spend their time going after 1 part to "maybe" get a small HP gain, but to attack all the percieved HP "bottlenecks" in the car at once and to do them in the most cost effective manner. So the powerkit gets dual intake, smoothed out plenum design (not as advances as RSS), smoothed out intake runners, header/exhaust modification, minor engine tweeks and computer changes that would guarantee porsche is able to make it's power goals.... 1hp more than the 996 GT3.

Actually Coryey I think they only change the plenum on the X51 cars as the intake manifolds have a different opening to them and it is to accomodate this. The plenum is changed but just for that purpose, it is still the basic design as the non X51 part.

If the RSS plenum works it would probably work even better with the x51 with the intake, throttle body and not to mention the cleaned up heads the X51 has along with the better exhaust manifolds.

Dave

I don't think it's a plastic part like the non powerkit models, atleast on the 996 it's not.

my feed back: i was goig to post a seprate post on my mods, but here it is. i first installed the rss plenum , and saw an immediate response in throttle and it pulls harder at speeds. when i rev the engine i do here a squish sound of the intake ??? anybody experience that. after that i installed the x51 carbon fibre air box, x51 headers, and modified the regular mufflers mk ii mod, and vow i even saw more difference then before, the car pulls harder now and take off is a lot easier and faster :) and exhaust sound is little louder and deeper, thats what i was looking for (200 $). next is euro sport suspension, i am assembling the suspension kit in my basement (winter project)

cheers

Ronnie

[Dave07997S]

Just to add to the topic. Also a disclaimer I have no association to RSS, I just do a lot of research before I go with anything on my car non-porsche.

The Plenum is a part that is changed on the power kit by porsche, though not to as engineered a device as the RSS piece. So on a powerkit car, the gains would be minimal. On a non-power kit car with the simple plastic T, there are areas of the RPM range where turbulance causes some hesitation in acceleration/deceleration. The molded shape of the RSS piece smooths those out so that it feels like a compeltey different car.

As for HP gains, their are some gains, but it took RSS nearly 2 years to bench flow this solution out. It wouldn't make much sense for Porsche to spend their time going after 1 part to "maybe" get a small HP gain, but to attack all the percieved HP "bottlenecks" in the car at once and to do them in the most cost effective manner. So the powerkit gets dual intake, smoothed out plenum design (not as advances as RSS), smoothed out intake runners, header/exhaust modification, minor engine tweeks and computer changes that would guarantee porsche is able to make it's power goals.... 1hp more than the 996 GT3.

Actually Coryey I think they only change the plenum on the X51 cars as the intake manifolds have a different opening to them and it is to accomodate this. The plenum is changed but just for that purpose, it is still the basic design as the non X51 part.

If the RSS plenum works it would probably work even better with the x51 with the intake, throttle body and not to mention the cleaned up heads the X51 has along with the better exhaust manifolds.

Dave

It's a very different cast part, not a plastic part like the non powerkit models, atleast on the 996 it's not.

It's plastic for the 997, the X51 throttle body for the 997 will fit the non X51 plenum according to RSS.

Dave

[phillipj]

Just to add to the topic. Also a disclaimer I have no association to RSS, I just do a lot of research before I go with anything on my car non-porsche.

The Plenum is a part that is changed on the power kit by porsche, though not to as engineered a device as the RSS piece. So on a powerkit car, the gains would be minimal. On a non-power kit car with the simple plastic T, there are areas of the RPM range where turbulance causes some hesitation in acceleration/deceleration. The molded shape of the RSS piece smooths those out so that it feels like a compeltey different car.

As for HP gains, their are some gains, but it took RSS nearly 2 years to bench flow this solution out. It wouldn't make much sense for Porsche to spend their time going after 1 part to "maybe" get a small HP gain, but to attack all the percieved HP "bottlenecks" in the car at once and to do them in the most cost effective manner. So the powerkit gets dual intake, smoothed out plenum design (not as advances as RSS), smoothed out intake runners, header/exhaust modification, minor engine tweeks and computer changes that would guarantee porsche is able to make it's power goals.... 1hp more than the 996 GT3.

Actually Coryey I think they only change the plenum on the X51 cars as the intake manifolds have a different opening to them and it is to accomodate this. The plenum is changed but just for that purpose, it is still the basic design as the non X51 part.

If the RSS plenum works it would probably work even better with the x51 with the intake, throttle body and not to mention the cleaned up heads the X51 has along with the better exhaust manifolds.

Dave

I don't think it's a plastic part like the non powerkit models, atleast on the 996 it's not.

my feed back: i was goig to post a seprate post on my mods, but here it is. i first installed the rss plenum , and saw an immediate response in throttle and it pulls harder at speeds. when i rev the engine i do here a squish sound of the intake ??? anybody experience that. after that i installed the x51 carbon fibre air box, x51 headers, and modified the regular mufflers mk ii mod, and vow i even saw more difference then before, the car pulls harder now and take off is a lot easier and faster :) and exhaust sound is little louder and deeper, thats what i was looking for (200 $). next is euro sport suspension, i am assembling the suspension kit in my basement (winter project)

cheers

Ronnie

Ronnie,

Glad to hear you have had the same kind of results I have had with the RSS plenum. Does the "squish" sound happen right when you hit the throttle? Like a sucking sound? I have that as well. But it's not a bad thing. I have a 996 with a chip, airbox mod and mufflers. All I can do is the headers and I think I have squeezed every last hp out of the 3.4.

Phillipj

[porschester]

Hi Phillipj...How are you?

Thank You very much for sharing your expertise and experience with your plenum. It seems that you have no regrets installing this simple mod. Yes mine is the RSS, and no I wont do the install myself. Rich the head mechanic at The Collection in Miami, is amazing and ultra qualified, and he is the only one that is allowed to work on my car. He is a conservative, so he is not so sold on the fact that 25HP gains would be achieved, but he seems to accept a 7 to 10HP gain once he installs the RSS plenum. I am going to follow advice and run couple 0-100mph straights before and then see the "after the Plenum effect". I may be dynoing the car once all is done. Now you have mentioned that you have a 996 with headers, plenum, and engine remaping, and that you have beaten a 997 4S on a street race....its a little hard to beleive, but if you can confirm again that your 996 now delivers more power than a 997 4S and explain I would be curious. Technically my 997 C4S with the X51 package intake, TUBI mufflers, and GIAC remaping should be faster, now than I adding EVO headers and Plenum, would I get even more pull and power throught the RPM's or just once the car goes beyond 4000 RPM? Again thanks for sharing your thaughts and experiences.

Cheers

Porschester

[phillipj]

Hi Phillipj...How are you?

Thank You very much for sharing your expertise and experience with your plenum. It seems that you have no regrets installing this simple mod. Yes mine is the RSS, and no I wont do the install myself. Rich the head mechanic at The Collection in Miami, is amazing and ultra qualified, and he is the only one that is allowed to work on my car. He is a conservative, so he is not so sold on the fact that 25HP gains would be achieved, but he seems to accept a 7 to 10HP gain once he installs the RSS plenum. I am going to follow advice and run couple 0-100mph straights before and then see the "after the Plenum effect". I may be dynoing the car once all is done. Now you have mentioned that you have a 996 with headers, plenum, and engine remaping, and that you have beaten a 997 4S on a street race....its a little hard to beleive, but if you can confirm again that your 996 now delivers more power than a 997 4S and explain I would be curious. Technically my 997 C4S with the X51 package intake, TUBI mufflers, and GIAC remaping should be faster, now than I adding EVO headers and Plenum, would I get even more pull and power throught the RPM's or just once the car goes beyond 4000 RPM? Again thanks for sharing your thaughts and experiences.

Cheers

Porschester,

I'm sorry if you thought that I beat the the 997 4S! I did not! But he did not pull away from me as strongly as one would expect. I was able to stay close. Your car already starts out with 55 hp more than mine plus with the mods you have already done it will really be sweet with the plenum addition.

Please let me know how the car perfoms one you get it all done. If you could do dyno tests that would be fantastic.

Take care

Phillipj

[porschester]

Hi everyone!

Yesterday I saw the Plenum at my dealer, Its definitely not as small as some people portrayed it to be. Most importantly, the shape, texture and finishings are impressive. Its definitely a piece that looks like a good quality and well manufactured piece, now lets hope that it performs as it claims. I have ordered the X51 headers, and as soon as they arrive, they will be installed alongside the PLENUM. Compared to the OEM plastic Plenum, the RSS is no doubt an improvement.

If anyone else has experience clear performance improvements with the Plenum, please share your experience.

Cheers

Porschester,

[neil.schneider]

Porchester,

Check your pm.

[MichaelL]

I had an IPD(sold by RSS) plenum installed on my 997S cabrio. I already had the AWE headers, catalytics & muffler, Evo airbox & Giac reflash. The apparent gains from the plenum were greater than that of the reflash, which was done after the other mods. Midrange power & torque were definitely increased. Prior to the plenum, the car pulled 321 rwhp on AWE's Mustang dyno. The reflash gave 7 rwhp. I will post results when I get it on the dyno again.