Intake plenum and 911 throttle body

[Ben006]

With my plenum the throttle body stays in the normal position and doesn't rub anywhere.

With 911 plenum it's another story

[Ben006]

I did a bit of reverse engineering on my own part now that I have a scanner !
here is the superposition of a stock 986 plenum, and my carbon fiber one !





As you can see, the transition is more straight between the two tubes and it has nicer bends.
For that I had to move the throttle body to the left and forward a bit to clear the starter solenoid !
What took months before would take only hours now !

[ike84]

Originally Posted by Ben006

I did a bit of reverse engineering on my own part now that I have a scanner !

here is the superposition of a stock 986 plenum, and my carbon fiber one !











As you can see, the transition is more straight between the two tubes and it has nicer bends.

For that I had to move the throttle body to the left and forward a bit to clear the starter solenoid !

What took months before would take only hours now !

I'm not sure how that would fixing the rubbing? My 996 plenum is a straight T and the issue is space between the starter housing and the engine cover, not the angle of the plenum. Also, if you've changed the angle/location of the TB, is there enough play in the stock piping to make up for this? My stock intake is long gone but from what I remember there's very little if any play in those accordion sections.

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[Ben006]

Well, mine doesn't rub because the throttle is where is was stock. No above the starter solenoid wich makes it too high.

you can not reuse the stock intake tube if you go to a bigger throttle body.

[Rpetrecz]

Originally Posted by Ben006

Well, mine doesn't rub because the throttle is where is was stock. No above the starter solenoid wich makes it too high.

you can not reuse the stock intake tube if you go to a bigger throttle body.

Now that some time has passed. Any luck with some dyno runs? Curious to see the numbers. Definitely interested if theres some good gains and they come back in stock.


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[Ben006]

Not really unfortunately, I've been too busy building the company for the last 6 months :/

I have a customer that picked up around 30Hp with the plenum, exhaust, and a tune on his 2.7L 986.

Right now I'm testing the 996 version. it still needs a bit of work...

I had a youtuber that was supposed to come (piston Kirk) but due to COVID he couldn't make it. We'll see in the winter if he can come and we'll do a back to back dyno with the plenum installed and removed.


Ben

[Rpetrecz]

Originally Posted by Ben006

Not really unfortunately, I've been too busy building the company for the last 6 months :/

I have a customer that picked up around 30Hp with the plenum, exhaust, and a tune on his 2.7L 986.

Right now I'm testing the 996 version. it still needs a bit of work...

I had a youtuber that was supposed to come (piston Kirk) but due to COVID he couldn't make it. We'll see in the winter if he can come and we'll do a back to back dyno with the plenum installed and removed.


Ben

The shop I work at has a dyno if you’re going to get these back in stock soon and want some solid data


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[PaulE]

Originally Posted by Rpetrecz

The shop I work at has a dyno if you’re going to get these back in stock soon and want some solid data


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And I'm a customer of that shop if you need a car to test it on! They already have the "before" dyno data on my car!

[El Vikingo Tropical]

Hi Ben
Have you made something for the 987 3,2?

[Ben006]

Originally Posted by Rpetrecz

The shop I work at has a dyno if you’re going to get these back in stock soon and want some solid data


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Originally Posted by PaulE

And I'm a customer of that shop if you need a car to test it on! They already have the "before" dyno data on my car!

Thanks guys !
I'm waiting on a few tools to make a V1.2, easier to fit and a bit better looking

Originally Posted by El Vikingo Tropical

Hi Ben
Have you made something for the 987 3,2?

I'm not sure of how the 3.2 987 inake is !
Is it the same as the 3.4 m97 or the same as the 3.2 m96 ?
if it's like the 3.4, I was to supposed to scan a car to finish the part... but the owner couldn't make it.
So I'm waiting on another occasion !

[Danimal]

Just thought I would post a link to the dyno on Ben’s website. There is also a YouTube video by Piston Kirk that reviews it. I’m on the fence about whether it’s worth it.


https://benautodesign.fr/en/home/20-plenum-admission-carbone-986.html

[Newsguy]

That link only takes one to the catalog page. No dyno there.

[Danimal]

If you scroll through the photos, it’s the last one on the right.

[Ben006]

Originally Posted by Newsguy

That link only takes one to the catalog page. No dyno there.

OOOOH it's been a while since I've last been here :O

Here is the dyno graf :
https://benautodesign.fr/261-large_default/plenum-admission-carbone-986.jpg

No other mod, not even an air filter, worst scenario for the plenum.
Still managed a noticeable gain !

[Danimal]

Curiosity got the better of me and I ordered one! I already have your shifter and side lever. Do you have any other 986 products available or in development?

Is there an air filter you recommend or have experience with?

[Ben006]

You ordered it from Uniwerks Design ?

For the air filter, if you are willing to clean it every 6months, a K&N does make a difference once you have the plenum !
If you don't want to bother with maintenance, the paper filter will do.

Fitting a 987 airbox is such a pain, both in term of physically fitting it and electronically making it work !
Though it's the best option for a 986...

Right now I'm stalled on the new and improved throttle pedal, as I had other products to finance first.

Once the others products are up and selling, and the new website is working, I'll get back to it

I do have rear toe links for 986 too. Adjustable to be able to retain good alignment on lowered cars.


And I'm also working on an affordable lap timer / g meter solution
Not 986 specific, but an affordable way of tracking lap times or rally stages time without hassle, USB-C power, setup a few coordinates and go !

As I still work alone (and got back to work for Porsche) everything takes soooo much time to develop...
Add to that my 3 broken cars

[Newsguy]

Ben, curious about 987 airboxes. I know the difficulty installing them even engine-out, but there are no electrical connections so what do mean when you say they are hard to integrate electronically?

[redpepperracing]

Originally Posted by Newsguy

Ben, curious about 987 airboxes. I know the difficulty installing them even engine-out, but there are no electrical connections so what do mean when you say they are hard to integrate electronically?

If I had to guess I would say he is referring to the fact that there is more airflow, especially if you do the larger throttle body, that the computer can't compensate. At least that was my experience. When warm and at idle I was showing around 17-18:1 AFR, which is VERY lean. I used an APEXi SAFC to modify the AFR and so far it's working very well. I should be going to the dyno either this week or next to see where I landed on power, and to possibly fine tune it.

@Ben006 you mentioned a throttle pedal, I was just about to order the assembly from Rennline, are you working on something similar? If so, any rough timeline? I'm not in a rush, but I'm willing to test anything for you! I already have your shifter and side bushing and LOVE it!

[Danimal]

By electronically, I thought he meant the tuning or flashing required to use the larger 987 MAF, or the finagling required to keep the 986 MAF.

But I didn’t think about the fuel trims… 🤔

[Ben006]

Originally Posted by Newsguy

Ben, curious about 987 airboxes. I know the difficulty installing them even engine-out, but there are no electrical connections so what do mean when you say they are hard to integrate electronically?

As redpepperracing said, you have to correct the AFR.
The 987 airbox uses a 3.5“ MAF housing.
The 986 a 3“.
The MAF sensor is the same, but in the bigger housing it measures considerably less air mass (as the velocity drops with the increased diameter).

When driving around, it’s usually OK as the the DME is running in closed loop, constantly adjusting the fuel trims to keep the afr in the right place.
Though, when going WOT, the DME is running in open loop, and relying on it’s long term fuel trim and adaptations to adjust fuel.
There is a chance of running quite lean.

The bigger throttle body has kind of a similar effect but the MAF is still reading correctly, so the adaptations and fuel trims are accurate
I always recommend driving around for a week after installing. You’ll know when the adaptations are done as you’ll take your car one day and feel the bump in power.
The first few days the car will actually loose power as the DME detects a change in the throttle position / MAF relation and pulls timing to avoid failure.



For the throttle pedal, as much as I would love to bring it to the market quickly… the last prototype I test myself wasn’t up to my liking (even though my guinea-pig loves it), and I made several changes to improve the movement of the pedal.
Rennline product is available and tested. I can’t compete for now :/ hopefully mid 2027

https://imgur.com/gallery/FVnLhJY#K3VckPV
https://imgur.com/gallery/FVnLhJY#qsWt8UB


It does look awesome in my opinion, and it articulates on a carbon fiber spring !
But I haven’t found the perfect position yet.
I do have a second version being tested in a 986 that races in the UK (samrs1400 on instagram if you guys want to check his page).
I have to fetch his feedback on it ! He wins races so it must be good 😂