Soooo, what does a bigger throttle body do? Installed mine! - 986 Forum - The Community for Porsche Boxster & Cayman Owners

I thought I start a new thread about this. Current setup:- -No snorkel -Stock airbox/filter -Stock MAF -Spectre hose to connect MAF and TB -997 throttle body -997 "T" -Underdrive pulley -Bypass pipes -Drilled muffler -Stock ECU When I got my car I had the feeling it was somehow restricted, especially between 4 to 5,000 rpm it felt flat. Don't get me wrong, drove nice and all but being somewhat spoiled I wanted more power. Also, having owned and driven several 911 (old and new) and other rather powerful cars I think there was more available. Reading this and other forums I concluded I was not alone. So I started to mod a bit, first was the UD pulley and Pedros Technotorque "T" and together with the bypass pipes, desnork and the slightly modded muffler things def got much better, no question. Engine felt much more alive so to say. The sound was domintaed by the intake noise (like a deeper/darker roar) and the flat spot was almost gone, great success! BTW, our long time Porsche tech at the dealership said "that thing goes, what did you do??" More and more reading led me to believe that a larger TB would be the way to go. First I was thinking IPD but that piece is just so expensive! So finally the new TB is in. Installation is straight forward. See other thread for details. OK, intial observations:- -Sound, this roar under WOT is gone, the engine note/intake sound is much lighter and suprisingly less overall noise. Finally the exhaust note can be heard, nice! Overall much more Porsche and not just intake noise.... I hope you understand what I mean!? -Absolutely no drone! Very quiet at highway speeds and under part throttle. -Engine feels way more alive compared to my previous setup, throttle response is "right there", nice! -No loss of torque in the lower rpms. -No more flat spot between 4/5,000 rpm, just smooth revs all the way, even powerband and great driveability, nice! -at 5,500 "VTEC kicks in, yo!" Sorry, couldn't resist, lol. Having said that my butt-o-meter is very pleased, nice! At that point the engine just sings and the sound is loud and mean, just like a good old Porsche should be! -Maybe it is just my imagination BUT I feel the engine runs smoother??? Oh, same tech drove my car again today and was impressed. So there, it's not only me... How much more HP? No idea! I wonder if I should get an ECU tune, though. That would be the last modification for me. I also would love to drive either back to back a stock 3.2S or, even better side by side, anyone in Utah up for it? Not for bragging and juvenile "racing" but to get a feel if all this modding really does something. Later, Andy

Nice write up Andy . At this point, it would nice to see someone on the forum offer this as a upgrade "package" that includes everything from the tb, plenum, ducting, clamps ect... so other members like me can buy one !

I'd like to see some before/after dyno results.

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Me too! Who is first?

This was just the confirmation I needed to start the hunt for parts on E-bay. One thing though, when I pulled my snorkle long time ago I noticed that the hole into the airbox is well below the diameter of the intake tube after the MAF housing. Guess that this is another restriction in the system that could be improved. Anyone know if this hole possible to enlarge in a safe way?

OK, folks, time for a little update! Car runs absolutely flawless, a joy to drive! Totally smooth and linear powerband. Sound is -for me- perfect, getting positive comments, not too loud but noticeable different. No drone, and as described earlier not so "dark". Once the engine hits 5,500 rpm there is def. more power compared to before. No CEL either. I am very happy with this mod. Again and again I am surprised how smooth the engine runs and how fast the car actually is. Later, Andy

Total $$ to do these mods? Total hp/tq gain? Subjective "butt dyno" results are fun, objective results are better. I am ashamed to admit that my car feels much more alive after I change the oil. Sad but true.

got mine going too - first drive yesterday. not a true 'back to back' as i've also cleaned injectors, added udp and added low-temp tstat, but now i can feel the car push me back in every gear over 4k rpm. also seems to rev higher more eagerly as 'blips' are quicker. very happy. i am also feeding the new plenum from a bmc dynamic air intake wich works good but has a low spot between the filter and maf and i'm worried about water collecting, so i am about to install a cayman air box. the cayman air box has a 3" inside diameter and a huge filter area. also, looks like it will only require a 45 degree silicone elbow to mate the cayman airbox to the new plenum/throttle body. when done it should be 99% oem - 997 plenum, 996/997/cayman throttle body, reuse 986 maf housing, cayman air box, some short silicone pieces. topless, if you read the other thread there is a guy on planet 9 who did the same thing to a cayman and got 8 hp proven on the dyno. cost is under $200 ($50 for the 997 plenum, $100 for a used throttle body, $50 for misc. silicone).

... a custom ECU remapping you're leaving a lot of power on the table. Happy Boxstering, Pedro

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Hi JD. if i'm not wrong, that is exactly what Pedro offers in his "Techno Power2" kit. TechnoPower2 Kit only with a remap for the ECU included.

So what I've gathered is that this won't work on the 2.5l?

i'm guessing here (so the info is worth what you pay for it) but i presume your car is cable throttle. so, you need to find a larger throttle body that is also cable throttle. according to the link below, the 1999 996 c2 throttle body is larger inside diameter, same outside diameter, bolts to the 2.5 plenum, and is cable operated. the intake duct should be direct connect also, unless the 996 throttle body is physically longer. http://986forum.com/forums/performance-technical-chat/13277-bigger-throttle-body.html should be plug and play. best to find the used part someplace, however, as Auto Atlanta is charging $1,366!

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Or go to Pedro's website, solution right there!

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Though the hole for the airbox is in fact smaller than the intake tube, it has a greater cross-sectional area than the throttle body. The cross-sectional areas are as follows: Base of the snorkel: 96mm X 75mm ellipse = 5,655 mm^2 68mm throttle body = 3,632 mm^2 74mm throttle body = 4,301 mm^2 Of course, it never hurts to get more flow, even if just to hear more of that lovely intake sound, but it's not a point of restriction.