Intake plenum and 911 throttle body

[madmodz]

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.

[eddy]

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.

Originally Posted by madmodz

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.

[Ben006]

Originally Posted by madmodz

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.

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!

[mavis.d]

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

[Ben006]

Thanks for the feedback!

I'm glad you like it too!

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

[mavis.d]

Originally Posted by Ben006

Thanks for the feedback!

I'm glad you like it too!

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.

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!

[Ben006]

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

[Ben006]

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.

[Gelbster]

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:
987 v 986 Air box
We really need Ben to design an easy to fit one!

[Ben006]

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. :/

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

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.

[Gelbster]

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

[The Radium King]

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

[Ben006]

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

[geraintthomas]

So just to clarify, all I'd need to purchase is a 997 75mm throttle body, fit this onto the manifold and the throttle body, and fit the existing intake tube onto the other end of the throttle body? Sorry, seemed to be a couple of things that have changed on this page and the previous page in terms of tubing!

[mavis.d]

Originally Posted by geraintthomas

So just to clarify, all I'd need to purchase is a 997 75mm throttle body, fit this onto the manifold and the throttle body, and fit the existing intake tube onto the other end of the throttle body? Sorry, seemed to be a couple of things that have changed on this page and the previous page in terms of tubing!

You will need a Throttle Body and larger intake tube and bends from the MAF to the T/Body. I still have to tidy up the pipework but if you look at my running report in Boxa.net there's a couple of pics. If I'm not too delicate after Christmas tipple on Tuesday I might sort it out then
http://www.boxa.net/forum/index.php?/topic/61193-mavisd-running-report/

[Ben006]

You can't reuse the stock intake tube since it's made for a 68mm TB, the 74mm won't fit inside!

Making an intake tube is just a matter of assembling an aluminum tube and two silicon coupleurs

Mavis, we can't see the page :/

[mavis.d]

Originally Posted by Ben006

You can't reuse the stock intake tube since it's made for a 68mm TB, the 74mm won't fit inside!

Making an intake tube is just a matter of assembling an aluminum tube and two silicon couplers

Mavis, we can't see the page :/

As you can see from the second pic the angle needs to tidied up. The aluminum tube is 76mm and each of the silicon couplings are 76-83mm

[Gelbster]

Mavis - it would be really great if you could specify the adapter coupling - do you mean a 90 degree elbow reducer 76/83mm ? Or a different angle? Like this??
eBay item number: 282061203413

Imagine how much easier your project would be if the airbox was not in the engine bay? Yes , a CAI outside the engine bay - it can be done ! But I don't want to hijack Ben's Thread.

[mavis.d]

Originally Posted by Gelbster

Mavis - it would be really great if you could specify the adapter coupling - do you mean a 90 degree elbow reducer 76/83mm ? Or a different angle? Like this??
eBay item number: 282061203413

Imagine how much easier your project would be if the airbox was not in the engine bay? Yes , a CAI outside the engine bay - it can be done ! But I don't want to hijack Ben's Thread.

It's a 90 degree elbow but I think a 45 might work better so may give it a go with one of those. BTW your ebay number brings up no items

[Gelbster]

Originally Posted by mavis.d

It's a 90 degree elbow but I think a 45 might work better so may give it a go with one of those. BTW your ebay number brings up no items

Try EBay USA ! It works just fine.