82 mm throttle body
 

Hey everyone, I wanted to share some pics of a project I'm finishing up. But first, a little back story...

2 years ago I was in the market for a sports car and stumbled upon a real garage queen - 00 base with 27k miles on it. I snatched it up and had Pat Williams do an IMS replacement for me and have loved the car ever since. Recently I moved to a rural area with wide open back roads and found myself wishing the car had a bit more oomph (mostly in terms of acceleration). So, the quest for more power began.

I know what everyone is thinking at this point "oh boy, not another one of these guys". To that end I will only say that I'm not doing this for racing purposes and I'm not looking to make the car spit flames out the back. I'm a tinkerer by nature and a bit of a scientist by trade so when really studying these cars it seemed to me that there are some obvious points that can changed and possibly improved. Plus, I'm curious to see what will happen lol. So, here we are, with the first part of that mad idea - bigger intake.

Here are the parts, it's really quite straightforward truthfully. Just a bit radical in execution
Early 996 plenum (for cable driven TB)
82 mm throttle body (cayenne turbo)
2 x 45 degree 3.5" silicone intake elbows
A short segment of 3.5" stainless
3.25" MAF housing (identical size to 996 but part is aftermarket Mercedes)
3.5" T shape short ram intake for GM (mostly found on C5 vettes)

Here are the porsche "speciality tools" used
3# mason hammer
4" hole saw and reciprocating saw
Factory jack (thanks porsche)

On to the execution
Gut the intake (drop the motor to do this, you can get the stock box out intact)
Strip the trunk and relocate the ECU a bit to gain slack on the wiring harness
Use mason hammer and jack to deform the cross member downward by 3/4 inch to gain enough clearance
Use hole saw to cut opening into firewall (gasp?!?!) between trunk and engine bay and use reciprocating saw to open up the too of the engine bay enclosure a bit.
Assemble and mount components

There are a few minor things from that point - opening up the wiring harness to get slack on the MAF sensor wiring to reach the new housing, extend the AOS hose to reach new attachment position, trim out the rough opening with rubber u moulding, and knock out the vents in the trunk to provide adequate ventilation.

And now, in the name of "pics or it didn't happen"...

Now look, I'm sure there are gonna be guys who are gonna gripe about not having dyno numbers (they will come but not until later in the project, lots more to come eventually) and criticize for loss of low end torque (which I realize is a very really possibility). But like I said, this is driven by a love of tinkering and a very itchy "what if".

The next step in this madness will be a 2.5" exhaust setup, and then plenty more after that. It's gonna take me a while to work through everything so bear with me, but I promise to keep pics rolling as the progress happens. https://uploads.tapatalk-cdn.com/202...6c279e7a4f.jpghttps://uploads.tapatalk-cdn.com/202...64c472d88d.jpg

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Looking Great so far!
Please keep us posted

Cheers!

Could you elaborate on this a bit? Where is your cold / fresh air coming from?

For now I've punch out the two vents in the rear of the trunk on the sides. These were there to vent the trunk when it heated up and communicates with the area where the stock muffler was located. If this isn't enough I can remove those popouts on the trunk floor to achieve the same effect. What I will ultimately wind up doing is using ABS to fabricate a dedicated "trunk space" and wall off all the intake components, which I am going to route down and out of those knockouts to twin turbos mounted below. With two young kids and a third on the way though, that part of the project is still quite a ways away lol. https://uploads.tapatalk-cdn.com/202...141b7f9679.jpg

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Thanks Muskoka! Btw I chimed in on your motor situation. My heart goes out to you.

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I stuck a 3.4 intake/throttle body and 3.8 997 exhaust manifolds on my 2.7 rallycross boxster. I can feel that i lost some low end torque but gained higher rpm HP. I'm rarely below 4000 rpm so it works for me. I moved the air filter inside the trunk and I'm surprised at how quickly the filter gets dirty. I've raised the trunk lid in hopes of drawing in more fresh air but I still need to find a way to get more fresh air inside the trunk. The air coming from the rear wheel well is very dirty. Granted I'm racing in dirt, so you should have a lot less than me.
http://986forum.com/forums/uploads02...1611627453.jpg
Here's my build thread

http://986forum.com/forums/show-tell-gallery/73877-6-months-live-build-thread-2.html

Very cool dude! I'm a big fan of your work, I nearly cried when I got to the end of your original build thread :(.

One idea I had was to utilize the rear wing (I stole the idea from lambo) drill holes in the front face of the wing so that when air hits it it will be directed down and into the trunk. With enough perforations there will probably be plenty of airflow there. The problem obviously is water there, but if it's a dedicated track car I would think it might work well.

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Who or what is lambo? I've been thinking some kind of scoop too. Just enough scoop to pressurize the trunk to keep dirty air from entering elsewhere inside the trunk. Any water that would enter would leak out the bottom of the trunk and shouldn't be able to enter the motor.

http://986forum.com/forums/uploads02...1612017481.jpg
Ideally something like this is needed for the environment I race in. I'm not sure I want to take on building something that big and complex though

Wow! You guys have taken this to a whole other level! Very cool! :cool:

The lamborghini aventador has an active air management system that is ridiculously complex and equally impressive. One of it's components is the rear wing, the pillars of which are hollow and when appropriate will open up vents to channel air downward through the pillars. We obviously don't have pillars on outlet wings, but the body of the wing is hollow right? And the bottom of it communicates with the trunk. So you could theoretically turn the front of the wing into swiss cheese and it would (hopefully) pressurize enough to force air into the trunk.

Btw, those vents on the side should have a flapper on them to keep dirt out. I don't know if you still have them but it may help putting them back in to keep the dirt from the wheels out.

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Thanks man! I'm a huge fan of your videos! The series you did on your lowering springs gave me the info I needed to install my coilovers, and your intake videos were super cool. I was sad to hear you toasted the motor but I'll bet your loving the 987. How does is compare to the 986? Ever find yourself wanting to go back?

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Yeah, I was reviewing one of my videos and, you know, I do have rather a soft spot for that `04... I'm just glad that Vanessa, a racer chick, decided to buy it. More track days to come! :dance:

I probably did take those off as they're right next to my exhaust now. I'm going to seal them off with some sheet aluminum and raise the front of my trunk a little higher. If you ever look at your car after it's driven in the rain, you'll see the air coming off the side of the B pillar swings back towards the center of the trunk creating a slight higher air pressure right where the raised portion of the trunk would be. In theory, making a great location for a scoop.
http://986forum.com/forums/uploads02...1612076507.jpg

Did you do anything to seal the ecu from dirt and water?

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The dme is tucked up under and I've never seen the need to. I've had boxsters at my yard with no trunk lids and the dme stayed dry even during the worst rain storms. The immobilizer I do have inside a bag and disconnected from the floor though. I have it sitting upright between the rocker panel and seat. I also have holes drilled in the floor so water cannot collect inside the floor pans. So far everything is staying dry. Before I reinstalled the windshield, the fuel gauge would stop working when it would get rained on. Immobilizer aside, these cars are pretty solid electrically. I've power washed the whole car inside and out. I wouldn't recommend cleaning the interior of your street car with a power washer. lol

That's good to know! I'm a huge fan of rhino lining the interior of off-road vehicles, but I'm going for a bit more a subtle look lol.

If you get on Amazon there are a ton of aftermarket hood and side scoops. They're primarily used by wannabe ricers but can function as a real scoop and they don't cost much. Instead of raising the trunk lid you could just cut a giant hole in it and mount a scoop over the hole. Kinda the poor man's version of your pic earlier. The aero images of our cars that I have seen show that to be a relatively low pressure area but I'm sure it can't hurt.

On a side note, when you flashed to 996 row, did your 986 guages still work appropriately? Whenever I get an hour off of daddy day care this is next on my list to do. I've read some say everything was fine, I've seen other say not so much. Reading wayne's article on cluster swaps it seems like after flashing to 996 I can go back through piwis and actually change the cluster back to 986 while keeping the 996 tune, but I haven't seen anyone actually detail doing this.

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Well lookie lookie - I was reading into oil cooler swaps/upgrades and found this pic. They're using it to vent an external oil cooler in a 987. That would do the trick though.

https://uploads.tapatalk-cdn.com/202...2cb6c8b45f.jpg

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I have an automatic cluster in my manual car with a 996 ROW tune. Everything works but the check engine light is on and it's not on when I had the 3.2 ROW tune. Honestly the temp gauge is the only one I care about though.
I might do something like that. The more I think about it, the more I like the dragster scoop sticking way high. Instead of the intake drawing air from the trunk, id point it straight up. I'd build another engine cover that the dragster scoop would then attach to. Not only would it get a slight tunnel ram effect, the extra air not getting ingested by the motor will help with cooling the motor. I have an overheating issue when racing in 90+ temps. It's in the 90's or higher for half the year down here. My only issue with the dragster scoop would be that I would probably have to modify the roof. I really don't want to do that because when time comes to part the car out, that roof would become worthless.

edit; Another benefit of the dragster scoop would be that hot air would escape easier from the engine bay when the car is not in use in between runs. I thinking I'm about to ruin a perfectly good roof. lol

Roof scoops are awesome, like the lotus exige. Definitely a complicated build but I think that your logic is spot on. Keep us posted!

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