Wow Ben.

I put 200 miles on the car today. Pulls much harder across the rpm range. I'm thrilled with the results. The quality of the piece is clear to see when you look at it, but the proof is in the pudding, and I have to say the pudding is pretty good.

I am headed back to the dyno (hopefully next week, waiting for a time from the shop) to verify the gains. Once that's done I will post about the install. Cliff's notes: 987 box is a pain (we knew that) Ben's Plenum is easy peasy; I also came up with a decent way to attach both using existing silicone piping and a bit of aluminum pipe. Stay tuned!

This P0306 code has hampered my ability to drive my car. It ran fine before. I pulled off a coil from another boxster and it did th e same thing. Flashing p0306. So what I have done:
1 coolant flush
2 oil change
3 pulled off intake/fuel rail/injectors and painted
4 plug change
5 tb and plenum change.

Would the fuel injector have anything to do with this code? I haven't really driven the car, just around the block a few times. It has no power.

the code came after the plug change right ?

Make sure you have a spark on cylinder number 6.
If you removed the injectors, did you change the seals?

One thing you can do is swap the plug/coil or injector (one at a time) from cylinder 6 to another and see if the code moves to that cylinder, once it moves, you've found what is causing the trouble :)

Yes, put new seals on the injectors, but had no ideal if they are balanced.

After I put back on the intake manifold, it wouldn't rev right. I was thinking I had a fowl plug. This was before I added your plenum, so I know that's not the issue. Tonight Im pulling the whole sides coils off and pushing them back in.

To check for spark, I put the plug in the coil and ground it while trying to start the car right?

I believe the coils ground through the bolt, so you have to have them in place :/

keep us in touch!

I have a dyno session set for tuesday am. i'll share results then!

Cool! Can't wait to know!

I think all three of you have put it in?

It's soon time to make them available!

If you're interested, you can already send me a PM!

Once I'm done with the shifters, the plenums are next!


Ben

Hi guys
I'm a bit behind on this due to holiday and work commitments. Also the 2 hoses I ordered came wrong so hope to get on with soon

After switching coils, I'm still pulling the P0306 code. Car wouldn't rev pass 2000. I unplugged the MAF and it revved fine. So next thing is I'm going to pull the MAF off another boxster and try it out. So heads up, if you pull one of these codes, unplug the MAF to see if it clears up the problem.

Weird that it only misfire on one cylinder though.
You might have a dirty cyl 6 injector too.

The injectors have a little disc filter in them.That may be plugged ? The injectors are pigs to remove with the engine in the car. Really need the special tool.

All right everyone, sorry for the delay.

I put 350 or so miles on the car after the 987 airbox and ben plenum/big tb install. It feels significantly stronger and the sound is better/louder than the desnorkeled 986 box i had before. I felt from the midrange up it really woke up the engine. From a "feel" perspective, this has been a wonderful upgrade.

Unfortunately I only got 3hp and 3tq according to the dyno (223 hp up to 226, 196tq up to 199). Temps were within a few degrees of one another, humidity was similar. I was quite surprised about the results. In order to better understand if my car is an anomaly it'd be great to see the results from a couple other cars.

The dyno guy (Hutter performance-- typically a GM tuner, but they had, of all things, a 962 there for a tune when I was there. They're a really well-respected shop in Northeast Ohio) said there was room for more power if I got a tune, but he didn't think there was a lot there to be gained.

So the numbers don't appear to be there, on my car, anyway, but if I hadn't gotten it dynoed I would've thought this was a solid 15 hp+ upgrade. Wish I could have reported a more positive result, and I hope I am an anomaly! I'm still very happy to have done this, though.

Eddy,

Thanks for posting the results. Did you get a graph showing output through the rev range? I would think with the mod there is more area under the curve, ie there is more power throughout the rev range vs being 'peaky'. I think max values are interesting, however more so is how much more power you are getting across all engine speeds. This is likely why you are feeling more of a positive difference than reflected in the max hp and tq values.

From what we have seen, your results are about average, with most of the small gains at the high end of the RPM curve.

I've been driving for little over a year with this mod and equally surprised at such low numbers. My experience with this mod is a bit of low end sacrifice with great mid/top. I've got to give it more gas out of the hole mostly due to the bigger TB but once past 4k it really wakes up. Acceleration is greatly improved once past that 4K area and quickly reaches redline.

On another note, before I swapped to the larger TB I ran just the stock 987 airbox and that alone made a big difference with the old setup. Just wanted to pass that on in case one would under go that route. So, I'm thinking a lot of the gains were probably mostly due to the 987 air supply.

I have found this mod to be wonderful! I did what is mostly this mod about 300 miles ago - I installed a 997 TB and plenum while keeping the stock 986 air box. I have a 986S with 2nd cat deletes, Crios mod muffler, and UDP. Also have a fresh MAF and spark plugs.

Just updating the throttle body and plenum has yielded fantastic gains for me - although subjective (no dyno) it is clear the car has increased power throughout the rev range and is much more responsive. My car always had great power above 5k rpm however was a little flat under 4k, as if it was waiting for a turbo to spool up. I wanted more uniform power delivery. With new TB and plenum it feels like I have a new engine - really opens it up from lower RPM's and loses much of the 'choked down' feeling. Character of engine feels more like a 911.

I am sure that Ben's plenum will bring great results as his design has smoother curves - and be easier to install. This is an easy, cheap mod that is highly impactful and one that I recommend.

Thanks for the feedbacks on your experiences guys, even though you're using a different solution :)

I also was really surprised with the results as I felt the same as you!

A flatter power curve, a small loss below 2000rpm, but a solid gain between 2000 and 4000, and still better breathing after.

You can see here: https://www.youtube.com/watch?v=i6wD-U7kONc that I'm always in second gear, between 3 and 4500rpm, and the car doesn't lack power despite having 117 000miles! No problem initiating a drift either!


I want to start selling them, but I really believe that you NEED supporting mods to get results.

Mavis, Madmodz, any update on yours ?

Ben

That is what counts, your satisfaction!
I bought the complete IPD package and it is noticeably louder and pulls stronger...and gas mileage went up a little. They (IPD) show an average of +15hp@wheels on their dyno charts. And I am happy, too.
...no matter if it is a +5 +10 or +15hp gain...it just feels better. That is what counts.

So after a long wait I finally got the plenum and 74mm t/body installed. Did it after work last night and finished tonight, it took about 3hrs in all. In the end I went for a K&N filter rather than the 987 air box due to time constraints, also looking how much space there isn't it looks a pig of a job!
Hard to get many thoughts on the way home as it was wet and dark so giving it full beans on country road didn't seem to sensible. I have a trip over the Yorkshire moors to Whitby this week so we'll see how it goes. :)

http://i898.photobucket.com/albums/a...d/IMG_2774.jpg

It looks really good in black and without oil stains like mine ^^

Wow, how did you get the 3/4" silicon hose to fit over the 1" AOS tube? It wasn't intended to be like that, but if it fits that's cool! It doesn't collapse at idle with the EZ-coil right?

Give it some time before getting results ;)

Ben

I did. I've been at an event all weekend and will share the graphs soon. it is a slight gain not just in peak but from the middle on up.

:eek: what should i have done with it?

Deleted due to sideways photo. see below for photo of dyno graph

You were supposed to cut the accordion hose and reuse the quick disconnect on the AOS, but there is not problem to do like you did :)

Did it take a lot of effort to get it like that??

Thanks Eddy for sharing!

http://986forum.com/forums/uploads02...1479171202.jpg

here you go

Ahh :o

It took a bit of time but then I put in some very hot water and it went on OK I did it that way because I don't like butchering standard kit in case I have to go back to square one in which case you're kippered unless you have a spare.

You can sacrifice that accordion hose without worrying, it will break if you look at it too much!

I'll try what you did on one of my spare AOS to see how it goes, it might make things easier for me!

Still can't get my car to drive right. Just got my maf in the mail. I was thinking of going to the stock plenum and tb to see if I can get this car running right. Just put a 2nd new plug in it and switched injector 5 over to injector 6. Still pulling P0306. Hopefully the maf is the issue.

Eddy, did you use the 997 airbox on both runs? That airbox alone should be at least 5-10 hp. Was a fan pointed to your air inlet during dyno.

First session was stock desnorkeled. second was 987 airbox + ben plenum + 74mm tb.

I did not have a fan blowing into the air inlet on either run. Good that I did the same thing twice for control, probably not ultimately best for numbers.

I'm going to start thinking about tunes and exhaust and hopefully these will start adding up. Yesterday was probably the last 70 degree day (it snowed today) in Northeast Ohio, so naturally I had the Boxster out. I swear these numbers are low, but I can't figure any reason why they'd be off.

The MAF would cause all cylinder to go bad.

What have you done so far to correct it?

By the way, I've tried to put the silicon hose like you did Mavis, and it went pretty well, so this is the final solution!

The plenums are officially available!

I realized that mine has been on for around 6000 miles, on trackday and two autocross events already!

So 3 weeks after finishing fitting it’s time for my update.

Fitting
Total time to fit took around 3hrs. Personally I found the ends of the Plenum a bit too rounded and felt this made it fiddly to fit. Less rounded and more of a chamfer may work better, that’s my just my opinion, other than that the plenum is really well made and Ben had gone to the trouble of painting it matt black which looked good. I didn’t have the time to fit a 987 air box so have gone for a K&N filter for the time being.

Driving
Seat of the pants says that there is a good improvement. Starts at 3 and builds over 4 becoming much stronger that before. I have the speed warning set to Back to the Future speed and find it coming on much more often, which is nice!

I had planned to do a session at the rolling road next week but can’t make it now so will try get there before Christmas and find what the figures say.

Great work Ben keep up the good work

Cheers
David

Thanks for the feedback!

I'm glad you like it too! :D

What do you mean by rounded? The curve radius between the two tubes is too big and interfere with the boot? If yes, it's unfortunately one of the compromises I made for better airflow.

The wheather started to get cooler down here ("cooler" but still South Florida) and my car is responding to it very positively! Way more than the other years, which makes me think that a remap could bring the car to another level!


So, guys, as I said, they're available! A good Christmas gift to offer to your Boxster ;)

I have to finish the update on the first page too... I whish we could change the thread's title.

PM me for any questions ;)

Ben

Hi Ben
No I meant the end of the T where it meets the inlet manifold. I found that it slipped of quite easily and took some time to get fitted correctly with no air leaks. Could it be a bit longer or would that make it too difficult to fit? It could be just me though!

http://i898.photobucket.com/albums/a...8280e324e1.jpg

I see!
Making it longer would make it a nighmare to fit :/

I changed the rake of the chamfer for the next ones, there will be more sealing surface ;)

Hi guys!

I'm proud to say that the first plenum has been sold!
(Well, the first that is not for testing)

I'll post pictures of it ;)

Ben.

Airbox upgrade to 987 or aftermarket
 

Mavis said:" I didn’t have the time to fit a 987 air box so have gone for a K&N filter for the time being."
Don't get the idea that removing the airbox and refitting the larger(better) 987 airbox is easy.
The stock airbox is difficult to remove because of the confined space. In theory you need to drop the engine a few inches, unbolt and move the Bank 2 inlet manifold. Even tht may not give sufficient clearance to remove it. That is why you'll fin Threads of despair describing how to cut up and break up the stock 986 airbox to remove it.
And you think that fitting the larger 987 airbox will be easier?
for example : "
On 8/27/2016 at 0:26 PM, marseille said:

it's not that hard to fit the 987 Airbox you just to remove all the unnecessary plastic from the airbox then the left hand side manifold, fuel rail remove the rear wheel to help with access in pulling the airbox down low enough to fit into the engine bay

10 minute job then😜
And more here:
http://986forum.com/forums/performance-technical-chat/32074-987-v-986-air-box-8.html
We really need Ben to design an easy to fit one!

The only reason why I still have the stock air box is because I HATE messing with this intake manifold on M96s and M97s! especially driver side. :/


Sounds like Porsche's instructions ^^
"Removing engine: Disconnect plugs, drain coolant, remove bolts, remove engine"

I don't think I can really improve on the aftermarket air boxes available. Cheaper: yes, better: hardly.

The geeks may find this related thread interesting even though it relates to an inferior application of the M96
IDP Plenum question - Rennlist Discussion Forums

well, if we are referencing rennlist ...

here is a similar thread but with some interesting comments by mr raby himself:

Alternative to IPD Plenum - Rennlist Discussion Forums

So what he says is that what I did was the right thing to do: Increasing the inside radius!