maf and throttle body diameter

[vijen6]

very interested in this also .. subscribed .. thanks for the great read so far TRK

[The Radium King]

sorry all. been too busy moving across the country, driving and, most recently, dealing with an (i hope) rms leak. all parts are in a box, hopefully to go in before the end of summer.

the road to hell ...

[Johnny Danger]

King,

Any updates on the project ?

[smlporsche]

Suscribed

TRK I would love to see some pics when installed (and hopefully dynoed)

[AndyA6]

So, what is new?

[The Radium King]

got the old stuff torn out and just putting it together now; i'll post pics and part numbers once i get it running in a few days.

[AndyA6]

Originally Posted by The Radium King

got the old stuff torn out and just putting it together now; i'll post pics and part numbers once i get it running in a few days.

Super! I am 100% sure a lot of us can't wait!

[al83s]

Thanks to this thread - I will have to start digging in my V8 Touareg to measure the throttle body there. Thing looks identical. and those are dime a dozen on ebay. Will post once measured.

[Homeboy981]

Any new news? Inquiring minds want to know! Have been waiting for the saga to continue.

[AndyA6]

Well, I will order the parts this or next week. Only thing I have to figure out how to connect from the TB to the (stock) intake.

[The Radium King]

i'll have more soon. what i can say is that the oem rubber couplers are stretchy enough to fit the larger plenum, but you can also get silicone reducers to do the job (dimensions posted earlier in this thread). the aos line will fit, but perhaps get a hair dryer/heat gun on it to make sure it doesn't crack when repositioning.

the larger 3" inside diameter throttle body has a 3.25" outside diameter. further, the oem maf housing/airbox has a 3" inside diameter and a 3.25" outside diameter. so, you need a duct that is 3" inside diameter but will fit over something 3.25" in diameter. several options:

- you can get that spectre flex 3" duct with rubber boots on each end (the rubber should stretch to 3.25"). folks say to not use rubber, but it's good enough for porsche ...

- you can do similar to what pedro does and use the oem duct; cut the resonator box out and tie to a 3.25" long-leg elbow to the throttle body. that dog don't hunt for me, however, as the oem duct is very thin and will easily collapse if you tighten the hose clamp too aggressively.

- you can try what i'm attempting - throttle body to 3.25" elbow. saw oem maf housing off of airbox and attach to elbow (this gets the maf closer to the throttle body like on the 996/997 for more responsive readings). 3" flex duct to bmc dynamic air intake located where oem airbox once was. This is a bastardisation of what has already been done by insite and jhandy (and others i'm sure).

** edit to add that i've read in several places that using a bmw 3-series maf housing is equivalent to sawing off the oem maf housing however, having ordered one and compared the two, the bmw unit is 70 mm inside diameter and the porsche unit is 74 mm (so, i've got a bmw maf housing for sale if anybody wants one ...).

[AndyA6]

Ordered the parts! Should have tem next week.....

[The Radium King]

ok, throttle body is in:



i used the oem rubber boots to install the plenum (otherwise use two 3.75" to 3.25" reducers). you can see the aos tube; not connected but will go on once i get some heat on it. the whole thing clears the engine cover, throttle connector plugs right in. removed the bracket that the previous throttle body bolted to; replaced the bolts that held it in place because they went straight through to the bellhousing (used washers to get same depth as previous).

so, final parts list is:

one $42.43 997 110 416 03 997 plenum
two $ 3.05 999 512 539 01 hose clamp (for the larger plenum)

four $ 0.27 900 385 025 04 bolt (larger throttle body requires shorter bolts)
four $ 0.15 N 011 524 27 washer (for above)
one $ 5.49 997 110 319 00 throttle body gasket

and one 74 mm throttle body from a 996, 987 or cayman. i bought mine used for $100 as there are lots around (996 from wreckers, cayman from guys who do the gt3 throttle body mod to their cars); find the right seller and you should be able to get the bolts, washers and gasket as well.

the final step is the connection from throttle body to maf housing. you need a 3" duct that will mate to the 3.25" flanges on the throttle body and the maf housing. i recommend the following $20 spectre 3" flexible duct because it has a rubber lip that should stretch to 3.25":

3" Dia Air Intake Flexi Ducting Air Intake Tubing Expands for Universal + CLAMPS | eBay

i haven't done that as i'm doing a custom intake as part of this project, but figure it should work ok. other options are a custom silicone build or repurpose the oem duct in some manner. regardless, all in for under $200.

and no, i've no idea if it improves power; by the time i get my car running i'll have the larger plenum and throttle body, new intake, udp, deleted AC, cleaned injectors and lighter rims; i'll have no idea where the improved performance is coming from (as long as there is improved performance ...).

[AndyA6]

Looking good! I ordered my parts already, they are on the way. Must have been hard to get those OM rubber boots on the larger Tee??

[The Radium King]

not at all; more than stretchy enough. gives it a stock appearance. what you see in that pic is less than an hour of work.

[AndyA6]

Well, I ordered silicon reducers, hope they work, otherwise I will follow your lead! Thanks for your feedback!

[The Radium King]

yeah, i'm going to keep an eye on the rubber to see how it wears; bad place for a leak. 12 years old and still supple, however; must be all the oil my aos is puking into my intake that's keeping it in good shape.

[AndyA6]

Getting there!








This Spectre air duct is not too bad! Got it at AutoZone today.... All other parts are brandnew.

Install should be fairly easy, only "worry" I have is the AOS connection, hopefully nothing will break.

[The Radium King]

the aos took me as long as fitting the plenum. get a heat gun and get the heat to it - it responds well to heat. a bit of meticulousness and you will get a perfect fit. the clips at each end of the aos tube don't like shear load (only tension) so make sure you form properly for the clips to hold.

looking good; you can be first to report perceived benefits.

[AndyA6]

Originally Posted by The Radium King

the aos took me as long as fitting the plenum. get a heat gun and get the heat to it - it responds well to heat. a bit of meticulousness and you will get a perfect fit. the clips at each end of the aos tube don't like shear load (only tension) so make sure you form properly for the clips to hold.

looking good; you can be first to report perceived benefits.

Thanks for the tip! And yes, hopefully there will be some gains, let's see