What can you tell me about the 74mm TB?

[KRAM36]

Originally Posted by edc

I think you keep confusing my cars and listing things which I haven't done! I have had 2 Boxsters both modded, but both different. One is a 550 with the standard 987 airbox and the other an early S.

I did the most work and dyno runs with the S. Mods as in my sig and posted previously ie no MAF change or 987 airbox and it totalled 20-25bhp.

As I mentioned, the TB with intake in isolation gave about 5bhp.

You don't have the same mod as Lapister posted. You can not compare what you did to what I did, they are not the same. I misinterpreted what JFP quoted you on, you listed larger MAF to TB pipe.

I'll stick by this mod gave the car way more then 5 hp gain. Even the 2004 550 Spyder had a 6 hp gain with just the 987 air box.

I've run a 2010 style Camaro SS and there was nowhere the Camaro could pull away from my Boxster. A 2010 Camaro SS has a ptwr of 0.1091983556 and in order to set with that, a 986 Boxster would need a 25 hp gain. My intake upgrade was done meticulously, not just thrown together.

[edc]

Of course the mods are not exactly the same as the other poster but given that nobody else seems willing to post up before and after dyno's or simply hasn't done it then I put my data up as a point of interest for comparison. It's not the be all and end all but at the end of the day I am not making these numbers up or telling you how it feels. I am just showing what those mods mean. My dyno plots show 5bhp or thereabouts for the intake, plenum and throttle body.

Nobody is questioning your intake. I'm sure every home DIY'er has got largely the same thing just made a slightly different way. Mine was just simple aluminium tubing and 4 ply silicone hose. I'm sure yours like mine is not using some fancy engineering computer program to test for optimum flow etc.

I wouldn't read too much in to the power and weight of other cars because if you go that far then you might as well consider diff ratios and gearing etc.

[KRAM36]

I wouldn't doubt your numbers, you didn't really do anything to help the car breath better using the stock 986 air box. You're probably lucky it gave you any hp increase.

[KRAM36]

I see now. Here is a oem picture if you need one.



Search 99611021571 - 99611021571 - Turbo Intake Plenum - ES#1483665

Crazy there is no 74mm option for you besides the IPD piece.

Maybe you could have someone with a 3D printer do one for you. There is a member on the forums here doing some 3D printed plenums to get a 74mm tb on the Boxster and keeping it pretty close to the factory location.

Intake plenum and 911 throttle body

[KRAM36]

I was wondering. They have in the description it was at the crank. Don't they have to put some kind of variable in the system when figuring the crank hp when doing the dyno from the wheels?

[Jake Raby]

On my dyno jet a well serviced 3.2S will put down 230HP in stock form.

We wear our dynes out here (we have two engine dynos and a chassis dyno) doing development. You learn a lot over time, but most of what you learn is that most dyno operators are completely lost.

Call your favorite supplier of go fast goodies and ask the first person who answers the phone what the 4 strokes of a 4 stroke engine are. You'll be transferred 2-3 times before anyone can tell you. Guaranteed.

Most of what people do to these engines result in LESS net power.

I have 996TT here now that one of these "tuners" and their products killed. They installed larger intake tubing without ensuring the suspension didn't contact the larger tubing with the car on the ground. Up in the air there's a ton of clearance, but on the ground the suspension punctured the tubing, generating debris which passed through a 3,000 dollar turbo and then sent that debris into the engine. The result is a 40 thousand dollar lesson being learned by the owner.

[stilov]

That sort of sounds like an install error. Although I do know of some inlet piping that previously was sold as a ready to fit product only later to realize it needed to altered to make work.
I feel that is a totally different subject. I originally started this thread based on a question about fitment of a throttlebody. I can see how adding a bigger throttlebody to a Boxster platform is a controversial issue. Maybe I'm a little sensitive because I have a 996t but for sure not all tuners are created equally.


Sent from my iPhone using Tapatalk

[Jake Raby]

The larger TB will usually hurt torque and only gain marginal HP, but over a very narrow power band. This is due to the intake plenums of the Boxster engine, as well as runner characteristics.

All combinations will vary in performance gains.

[KRAM36]

Originally Posted by Jake Raby

The larger TB will usually hurt torque and only gain marginal HP, but over a very narrow power band. This is due to the intake plenums of the Boxster engine, as well as runner characteristics.

All combinations will vary in performance gains.

That ending line is your saving grace. I can tell you without a doubt, cross my heart and hope to die, that my intake mods has made my car a beats. It has not lost any torque or a narrow in power band. My car is flat out hauling through the whole RPM range. I don't need a dyno to tell me the car has gain a substantial performance gain. It flat gets with it. Do it right and you will be rewarded.

[stilov]

Finally got some time to compare my good v bad throttle body just FYI.


Sent from my iPhone using Tapatalk