Stock airbox intake flow (pics)

[SpIcEz]

Originally Posted by maytag

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Start with the exhaust. Get it to breathe better there, then maybe a hi flow air filter can help. Then increase the size of the TB, and you will want to increase the size of the intake feeding it. But just throwing on an intake that can feed more air than the motor can use isn't going to help it.

And then there's the risk of introducing hot air while you're at it.

I 100% agree, that an intake by itself, wont give you much.
Exhaust, plenum, throttle body, etc.. are necessary to actually benefit.

And we are agreed as well that heat management is key. Its obvious by the placement and closed nature of our engine bay that, its not enough to just throw in a filter with more direct intake route.

There just seems to be this contention that there is no way to make more power than stock box, which I just cant believe from experience.

[maytag]

Originally Posted by SpIcEz

There just seems to be this contention that there is no way to make more power than stock box, which I just cant believe from experience.

Nah, you're right. I think where things get lost is the real cost:benefit. Take my 5.7 hemi: Its pretty easy to add a CAI and swap a tune and find 20hp. Hell you can find 12-15 with the CAI-alone.
But with the m96 in the boxster, you need to spend large dollars on multiple modifications to see the same sorts of increases.

On mine, I've done headers, de-cat, by-pass valves, 78mm tb, 987 airbox and intake with the EVO filter and riser , lwfw, udp, and a tune. Yeah.... add that up in your head. Haha. I bet I've found maybe 5HP on top. (Though I've fattened the curve a bunch). I haven't had it on a dyno, but I've got a lot of years on the "butt-dyno".

Why'd I do it then?
Can't help myself. I modify, therefore I am. It's what I do. It's the bigger part of the fun of an enthusiast-car, to me. I've got some mods I don't like much, and next year I'll change them.

I think ya just have to be realistic about what you may find, and to many / most people the cost: benefit to modifying the M96 in the boxster just isn't there.

Fun fact: i'd probably get more performance increase by going on a diet and dropping 30lbs. Hahaha

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[Starter986]

Originally Posted by maytag

Fun fact: i'd probably get more performance increase by going on a diet and dropping 30lbs. Hahaha

There's 60HP right there. :dance:

[SpIcEz]

Originally Posted by maytag

Fun fact: i'd probably get more performance increase by going on a diet and dropping 30lbs. Hahaha

Indeed, Im in that same boat

Installed Sparco Chrono Road seats, as my stock seats where torn appart and wanted something to hold me better.

However, to fit my fat a$$ I probably ended up with heavier seats than stock, or at the least no weight loss...

They look good though

As for the rest, you are right, people assume because you get massive intake gains on some cars, you will get it on others.

I agree with "I modify, therefore I am!"

It takes every inch of my soul not to tinker with my winter car, but so far, so good.

[Topless]

The whole point of modding a car is to measurably increase performance and that is tougher on a Porsche because those crazy Germans already did a pretty good job. Just bolting on sexy parts won't get it done. We need independent measurement and verification to separate legit gains from the BS, and get beyond the marketing hype which is pretty rampant.

All of this 986 stuff was tested extensively about 20 years ago and the results were interesting and often disappointing. Aftermarket products failed to meet their claimed HP improvements across the board. Fabspeed makes sexy products and their exhaust is arguably the best looking and best sounding of all aftermarket exhausts. They claimed a 22hp bolt-on gain but independent testing showed the stock exhaust actually made more power with a fatter torque curve. They claimed a 15hp gain with the EVO intake but independent testing showed -3hp and higher intake temps.

Underdrive pulley- Verified 3-5hp gain to the wheels across the RPM range by reducing parasitic drag.

Weight loss- Verified improvements in acceleration, braking, and cornering.

Plenum- Combined with TB, exhaust, and custom software tuning- 10-15hp depending on model with more improvement on the 3.2L.

Airbox- 987 box performed the best gaining 1-2hp on 3.2L

If we are serious about improving performance we need to do the math, and before and after testing to confirm that gains are real and not just marketing BS.

In an earlier life, we used to hot rod Ford, Chevy, and Honda motors to race at the drag strip and off road. Detroit mfg tolerances were pretty loose then with a lot of internal friction and you could make 30hp verified simply with a balance and blueprint, getting everything up to the engineering specs. Add a real intake manifold, Holley carb and custom exhaust instead of those stamped things from Detroit and there might be another 30hp verified as we allowed all that displacement to measurably breathe better. Porsche doesn't miss much, tolerances are a lot tighter, and we have to get more creative to squeeze more power from these well-tuned little mills.

Tuning is fun as long as you independently measure and verify gains along the way. This requires regular visits to a fairly precise dyno. Trusting aftermarket marketing hype is a fools errand and leads to disappointment.

These guys did a pretty good study on Boxster tuning and they did significant before and after testing along the way. A few interesting findings: They did not find improvements with an underdrive pulley as many other's have seen and verified. Also the stage 1 ECU remap caused the power to be down 10 hp vs the stock ECU tune on their modded car with a rich AFR. A custom dyno tune would probably deliver more juice if they got the AFR really dialed in.
https://www.youtube.com/watch?v=kja5LSsUT_g

[Hasbro]

Originally Posted by Topless

Underdrive pulley- Verified 3-5hp gain to the wheels across the RPM range by reducing parasitic drag.

Weight loss- Verified improvements in acceleration, braking, and cornering.

Plenum- Combined with TB, exhaust, and custom software tuning- 10-15hp depending on model with more improvement on the 3.2L.

Airbox- 987 box performed the best gaining 1-2hp on 3.2L

I'll put this here instead of a new thread as it is somewhat applicable. Care to comment on my plans on a 2.5 base? I'm thinking maybe +10 whp?

- Underdrive pully - check.

- Lightened flywheel/clutch? - In a nutshell, Raby said the 2.5 could handle this the best. Is there such a thing as a lightened dual mass flywheel?

- Weight loss- -367 lbs. (2,455) so far. Goal around 2,350, including weight added back on (structural stiffening and body work/aero).

- TB, software?, exhaust (headers, 2 cats, no mufflers (for weight loss) - still need the headers. Will I need 2.5 specific headers? Would Pedro's system work adequately with the semi-custom software? Alternatives; rolling dyno plus? I'm looking for a broad range torque improvement, not 6700 rpm hp. This is more of an auto-x/street car than track - built for fun and don't care about being class competitive.

- Manual steering.

- Re-working of body/drag but I'll leave this alone for now but it will reduce the hp required to go x mph.

[Topless]

Originally Posted by Hasbro

I'll put this here instead of a new thread as it is somewhat applicable. Care to comment on my plans on a 2.5 base? I'm thinking maybe +10 whp?

- Underdrive pully - check.

- Lightened flywheel/clutch? - In a nutshell, Raby said the 2.5 could handle this the best. Is there such a thing as a lightened dual mass flywheel?

- Weight loss- -367 lbs. (2,455) so far. Goal around 2,350, including weight added back on (structural stiffening and body work/aero).

- TB, software?, exhaust (headers, 2 cats, no mufflers (for weight loss) - still need the headers. Will I need 2.5 specific headers? Would Pedro's system work adequately with the semi-custom software? Alternatives; rolling dyno plus? I'm looking for a broad range torque improvement, not 6700 rpm hp. This is more of an auto-x/street car than track - built for fun and don't care about being class competitive.

- Manual steering.

- Re-working of body/drag but I'll leave this alone for now but it will reduce the hp required to go x mph.

Weight loss and UD pulley are a slam dunk. Intake/exhaust/DME software are a moving target and best done together with a custom dyno tune. I don't see much benefit in any off-the-shelf flash unless it gets further tuned to your specific car and mods. Everything needs to work well together and then you can find some hidden HP.

A lightweight flywheel was on my brother's 2.5L car while mine retained the dual mass. It definitely spooled up faster and was a little quirkier to drive around town. We never dyno'd B/A this change and we noticed no difference in lap times. He was usually a bit quicker on tight tracks and I was quicker on more open tracks, always within a few tenths.

The only benefit to me for manual steering is a little weight loss. The PS pump is very reliable once the UD pulley is installed.

Good luck and test/verify as you go!

[Fiddlebog]

For manual steering, is anything needed to be done to the rack, or just remove the pump and lines?

[piper6909]

Originally Posted by maytag

]

Fun fact: i'd probably get more performance increase by going on a diet and dropping 30lbs. Hahaha

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Me too!! We should get a group of members and do a "Biggest Loser: 986 Edition"!