Bang for Buck Mod

[KRAM36]

Originally Posted by jsceash

So you took the end out of the 90mm MAF, jerry rigged it in the 75mm original MAF, which you then reused. The air box is mounted without all the grommets and screw, and the tubing although larger than stock is still reduce throughout. Why did you bother?

You could have got the same air flow improvement out of the original air box by de-snorkeling, replacing the original inlet tube with a 3" smooth pipe with no chambers, and a high flow air filter.

The improvement for this mod come from using the 90mm MAF and 3-1/2" air inlet tube.



The metal above the MAF inlet joint need dented up about 1/2" (Brad Roberts told Kram this needed to be done in his previous posts about this mod) All the screws and grommets can then be mounted along with the 987 MAF. 1, 3.5" coupling sleeve from eBay. 1, 3.5" to 3.25" 90 degree elbow from eBay, 1, 8" x 3.5" aluminum air tub from eBay use about 4", 4, 85mm - 100mm clamps I use 4 stock 987 intake clamps. No glue no epoxy no rigged connector. The tune from a 2004 986-550 Spyder

What isn't mentioned is the cross flow tube need removed, TB needs removed, plenum needs removed, the drive side intake need removed, fuel rail needs disconnected, wire harness needs unclipped from plugs injectors and sensor on the driver side and pulled back. Driver side air grill and the snorkel need removed. before you can remove or install the old air box and the 987 air box. To improve access to the lower part taking off the driver side rear wheel and wheel inter liner help along with the driver side header pipes.

Or remove or drop the engine 2-3".

"jerry rigged"? I'll have you know that's the most professional looking 987 air box to stock 986 MAF I've ever seen. Why did I bother? 20 HP gain for not much money is why.

This is "jerry rigged".





Are you just a complainer? Did you not read my post as to why I did it this way? I also gave the links on how the installs are done and then posted the parts needed.

Your in a dream world if you think a 986 air box with a high flow filter is going to match the air flow the 987 air box will deliver, even with using the stock 986 MAF housing. My car is so much faster after this intake upgrade I have to get new brakes as I'm hitting the corners at such a higher rate of speed, the stock brakes are not cutting it, even with the "restrictions" and no tune needed.

Question asked, Best Bang for Buck Mod. So do you want to spend $200 on a UPD for 5 hp gain or spend $300 and get 20 HP? The car roars at WOT with the snorkel on, runs better through the hole RPM range. This is a Mod you will feel, UPD, not so much.

[jsceash]

Are you just a complainer? Did you not read my post as to why I did it this way? I also gave the links on how the installs are done and then posted the parts needed.

Your in a dream world if you think a 986 air box with a high flow filter is going to match the air flow the 987 air box will deliver, even with using the stock 986 MAF housing. My car is so much faster after this intake upgrade I have to get new brakes as I'm hitting the corners at such a higher rate of speed, the stock brakes are not cutting it, even with the "restrictions" and no tune needed.

No I don't live in a dream world. If you have some documented data on your HP gain post it so we can see.

Here is what I've done in five years of tracking a my car starting with the original 2.7 motor. I can say for some time I've run almost every configuration of air intake on track and have hours of data recording to back them up.

In the 2.7 with an smooth 3-1/4" inlet pipe upgrade plenum and 74mm throttle body stock MAF stock air box desnorkled. My recorded improvement is 19-20 HP

The next year I ran a Agency power box with a cone filter a SLIGHT improvement.

The next year I had the 987 box stock MAF. The rest was the same as above. I had "NO" improvement in HP or Torque. But I wasted an entire weekend getting it installed IHAVE NO PROBLEM SAYING IT WAS JERRY RIGGED. I could only get 2 bolts in it was cockeyed high in the front low in the back and towards the motor in the rear.

Using your prices the straight pipe throttle body and plenum would have been $170 without 4-6hours removing the intake injectors and all the other crap.

This is a fact I can say the 987 air box never was installed right until I removed the 2.7 motor to install the 3.2/3.6 conversion. It's flush to the cover now the flange had vibrated against the top spot Brad had previously mentioned and made a flat spot that was nearly through. It was bad enough I bought another one.

[KRAM36]

Originally Posted by jsceash

No I don't live in a dream world. If you have some documented data on your HP gain post it so we can see.

Here is what I've done in five years of tracking a my car starting with the original 2.7 motor. I can say for some time I've run almost every configuration of air intake on track and have hours of data recording to back them up.

In the 2.7 with an smooth 3-1/4" inlet pipe upgrade plenum and 74mm throttle body stock MAF stock air box desnorkled. My recorded improvement is 19-20 HP

The next year I ran a Agency power box with a cone filter a SLIGHT improvement.

The next year I had the 987 box stock MAF. The rest was the same as above. I had "NO" improvement in HP or Torque. But I wasted an entire weekend getting it installed IHAVE NO PROBLEM SAYING IT WAS JERRY RIGGED. I could only get 2 bolts in it was cockeyed high in the front low in the back and towards the motor in the rear.

Using your prices the straight pipe throttle body and plenum would have been $170 without 4-6hours removing the intake injectors and all the other crap.

This is a fact I can say the 987 air box never was installed right until I removed the 2.7 motor to install the 3.2/3.6 conversion. It's flush to the cover now the flange had vibrated against the top spot Brad had previously mentioned and made a flat spot that was nearly through. It was bad enough I bought another one.

This may be the case on your setup with a 2.7L engine. I've read the stock ECU tune can only compensate up to a 20% increase in air flow. I've also read that the ECU can not correctly read the air volume when using the 987 MAF house without a tune. Sounds like when you put the 987 air box with the 987 MAF house you exceeded the 20% air flow, which would yield the car running lean and with the 987 MAF house a tune was needed. I'm surprised your HP numbers didn't go down.

It's also a known fact that Porsche put the smaller air box on the 986 to keep it's performance down. They cut the nuts off the 986 with that air box.

Originally Posted by Brad Roberts

It's tough online to see me smiling when I post "tongue in cheek" comments Thanks for not getting offended. It was meant in jest.

Yes, it went away and the engine air inlet temp went WAY down. Down to what we expected to see based on a stock CaymanS. GM has a division dedicated to inlet air temp on the Corvettes. After meeting a person who works in that group, and what I have seen on professionally raced Boxster's and Cayman's... I take air inlet very serious (to the point of covering the entire intake/air box/piping in the gold foil to keep the temps down. Heat kills!!!

Porsche cut the nuts off the Boxster's and Caymans. The trend for larger throttle bodies and larger headers is well founded, but you have to match it with a larger air box. So far the CaymanS airbox has proven to be *good* up to 420hp. I have not tested past that (GrandAm M97 engine in a CaymanS)

[KRAM36]

Originally Posted by jsceash

No I don't live in a dream world. If you have some documented data on your HP gain post it so we can see.

Here is what I've done in five years of tracking a my car starting with the original 2.7 motor. I can say for some time I've run almost every configuration of air intake on track and have hours of data recording to back them up.

In the 2.7 with an smooth 3-1/4" inlet pipe upgrade plenum and 74mm throttle body stock MAF stock air box desnorkled. My recorded improvement is 19-20 HP

The next year I ran a Agency power box with a cone filter a SLIGHT improvement.

The next year I had the 987 box stock MAF. The rest was the same as above. I had "NO" improvement in HP or Torque. But I wasted an entire weekend getting it installed IHAVE NO PROBLEM SAYING IT WAS JERRY RIGGED. I could only get 2 bolts in it was cockeyed high in the front low in the back and towards the motor in the rear.

Using your prices the straight pipe throttle body and plenum would have been $170 without 4-6hours removing the intake injectors and all the other crap.

This is a fact I can say the 987 air box never was installed right until I removed the 2.7 motor to install the 3.2/3.6 conversion. It's flush to the cover now the flange had vibrated against the top spot Brad had previously mentioned and made a flat spot that was nearly through. It was bad enough I bought another one.

You do make a good point, in the fact you can get a 20 HP gain with just upgrading the intake from the stock 986 air box.

$170 to get 20 HP increase, hands down the best bang mod for the money. Really makes the UPD for $200 and 5 HP gain look even more silly.

I've always estimated I got a 20 HP increase, but always felt is was more. My brother who has taken many rides and driven my Boxster before the intake and air box upgrade. I took him for a ride after the upgrade and also let him drive it. I then told him about the header, cat delete pipe, Borla muffler, 987 MAF house and larger intake pipping with a tune plans. His exact words were. "Your car is too fast right now, you don't need to do those upgrades". He is 6'-3" at 260lbs, even with the extra weight of him in the car, his impression was the car is too fast already.

[The Radium King]

the tune from a 2004 spyder will only work on a 2002- car (7.8 dme). I was able to get the airbox in without denting anything (you do have to modify the airbox by removing the muffler, and getting it in is a bear but very possible with engine in place).

from what i recall the 987 MAF housing ID is 83mm not 90mm (vs the 986 76mm) but yes, reusing the oem maf housing does keep one restriction in the system but is necessary unless you retune your car - oem tunes can be used (5 mins with your indy and a pst2/piwis):

2002- use the spyder tune
-2000 use a 2000, 2001 996 C2 3.4L e-gas tune (the 1999 was cable throttle)
5.2 dme cars? dunno. cable throttle cars? dunno.

while keeping the restriction in the system isn't the perfect solution, you still see benefits as can be attested to by most who have done the work. compared side by side, there is no argument that the 987 airbox can move more air than the 986. the other thing to realise is that this is a change to the overall principle of operation of the intake - from a reducing diameter system designed to accelerate the air into the cylinders and facilitate induction at low rpms, to an unrestricted system designed to move a lot of air at higher rpms - in this context reusing the oem maf housing is not that bad a compromise, although I could understand in jsceash's situation the 3.6 might suffer more from the restriction than a 2.7/3.2 car.

[Dlirium]

Holy Cow, KRAM! Thanks for sharing, this is an amazing write up! Now I just have to get up the nerve to try!!

[KRAM36]

Originally Posted by Dlirium

Holy Cow, KRAM! Thanks for sharing, this is an amazing write up! Now I just have to get up the nerve to try!!

You're welcome. This is a time consuming Mod. The hardest part I found was getting the last bolt out of the intake plenum. I took the Plenum completely out of the way, makes installing the 987 air box easy. I didn't have a hard time at all putting the 987 air box in place. Second hardest thing, making sure you cut the silicone hose to the proper length. Tip on cutting the silicone hose itself, take one of the clamps and tighten it down on the hose were you want to cut it, then just use a box knife cutting right at the clamp, makes a nice straight cut.

[mikesz]

Thank you, kram and all the others who have contributed to this and other threads that deal with this topic. I have already purchased the 987 airbox, TB, and Y connector. However, I am confused when you talk about the MAF housing. I understand you must use the stock 986 housing and MAF sensor but don't understand when you say you put the 986 housing into the 987 housing so you can clip it on?? I am not getting a visual? also, somewhere in these threads there is discussion regarding a e49 5 series BMW MAF housing?? Can someone explain and add pics if possible? Also, has anyone done this mod without removing the Left intake manifold? Can the airbox be removed/installed by just lowering the engine?

[KRAM36]

987 air box are all the same. When looking for the 996 Throttle Body, make sure it came off a 996 model number 99660511501, some people will list them for a 996 and they came off a Boxster. The 997 Distribution T make sure you get one that looks like the one I linked to, the turbo models are different. You probably can't beat that price.

You could also look for a 997 TB model number 99760511501.

[Stroked & Blown]

Anyone see gains on a 2.5, or is the stock air box 'right sized' for the smaller motor?

[KRAM36]

Originally Posted by Stroked & Blown

Anyone see gains on a 2.5, or is the stock air box 'right sized' for the smaller motor?

Pedro offers a kit.

TechnoPower Kit

You can have this guy bore your TB and do your own thing for the rest of the air intake system.

http://www.maxbore.com/pictures.html

[Lapister]

Kram, Did you end up shaving off the top of the 997 -T for clearance? I recall you expressing earlier in another thread of a thick ridge hitting starter.

[KRAM36]

Originally Posted by Lapister

Kram, Did you end up shaving off the top of the 997 -T for clearance? I recall you expressing earlier in another thread of a thick ridge hitting starter.

I have not yet. I plan on doing it though. It's not a huge issue and depending on the car's transmission will depend if the starter get's in the way. The trans on the left is a 6 speed and the Tiptronic trans has the starter in the same higher location, so it get's in the way.



Just talked with the man at Softronic. He said using the larger 987 MAF Housing will yield no gain with the 996 TB, is could also hurt the cars performance even with a tune. He also said do not go to a larger TB, like a 82mm TB on a stock 3.2L engine (no internal engine changes). It will actually hurt the cars low end performance. The 996 TB he says is what to go with and stick to the 986 MAF housing.

So all I have to do now is get my exhaust upgrades done, forget the larger 987 MAF housing. I will be getting a tune from Softronic as I want every bit of HP I can get out of this engine.

[Lapister]

Thanks, Thats nice to know we are utilizing the best combo of parts to up our ponies. And I hope you don't mind one more question. Just for clarity, for our 987 intake the only needed part is the unit and flat snorkel? I was concerned about the small rubber elbow for Maf to air but I don't need either.correct? Thanks,

[The Radium King]

Originally Posted by KRAM36

Just talked with the man at Softronic. He said using the larger 987 MAF Housing will yield no gain with the 996 TB, is could also hurt the cars performance even with a tune. He also said do not go to a larger TB, like a 82mm TB on a stock 3.2L engine (no internal engine changes). It will actually hurt the cars low end performance. The 996 TB he says is what to go with and stick to the 986 MAF housing.

umm ... so what was porsche thinking when they put it on the 550 and added 8 hp? the 550 is basically your engine with the 987 airbox / maf housing and a factory tune.

no gain? not likely. most likely no gain for softronic. you've been upsold. instead of 1/2 hour at your indy getting the spyder tune pushed onto your car, now you're out $800 to ... softronic.

[KRAM36]

Got the larger pipe ordered, but it's coming out of China and had to order a fitting for the Tiptronic venturi tube from China too, then will have to have the fitting welded onto the pipe. So it will be a bit before I have any feedback on that.

[Lapister]

Kram, Need another clarification, on the Honeycomb 75mm for Maf they come in different ratios for cells. Remember which one? Seems default on website is 4:1 ratio. Gathered most parts and getting jazzed!

[jsceash]

The real problem isn't the 987 MAF or the 996, 76mm throttle body. It the stock 996 Plenum. There is a lot of engineering data some in this post.
http://986forum.com/forums/general-discussions/31693-maf-throttle-body-diameter-10.html
That discuss the problem, which is the Plenum design that create a massive turbulent blockage.
Then a spin off where a members was designing a retro plenum, very similar to IPD's design. I don't know where this led after the thread died.
Intake plenum and 911 throttle body

The IPD does make this transition but the price is somewhat objectionable to some members.

[KRAM36]

Originally Posted by Lapister

Kram, Need another clarification, on the Honeycomb 75mm for Maf they come in different ratios for cells. Remember which one? Seems default on website is 4:1 ratio. Gathered most parts and getting jazzed!

Yes 4:1

Originally Posted by Reebuck1

KRAM36 where did you order the larger pipe from and what size was it?
I to am wondering if the larger diameter exhaust pipe will give me a pick up in HP
and still provide enough back pressure. My CAT by pass is 40mm.

80mm 3 1 8" inch Aluminum Turbo Intercooler Pipe Piping Tube Tubing Straight | eBay

Originally Posted by jsceash

The real problem isn't the 987 MAF or the 996, 76mm throttle body. It the stock 996 Plenum. There is a lot of engineering data some in this post.
http://986forum.com/forums/general-discussions/31693-maf-throttle-body-diameter-10.html
That discuss the problem, which is the Plenum design that create a massive turbulent blockage.
Then a spin off where a members was designing a retro plenum, very similar to IPD's design. I don't know where this led after the thread died.
Intake plenum and 911 throttle body

The IPD does make this transition but the price is somewhat objectionable to some members.

The 987 MAF housing is an issue. The ECU can not read the air volume properly with the 987 MAF housing. You will get a CEL and run the car lean using it without a tune.

The 997 Distribution T has just about zero turbulence because of the generous radius it has coming off the TB tube, allowing the air to flow smoothly into the plenum.

IDP plenums are a waste of money. I had a long discussion with the guy that does the tuning at Softronic and he said never to use one. He also said not to use the 987 MAF housing as it will hinder low end performance, unless your foot is to the floor 90%, using the 987 MAF housing is a bad idea for a street car.

[Reebuck1]

KRAM36 where did you order the larger pipe from and what size was it?
I to am wondering if the larger diameter exhaust pipe will give me a pick up in HP
and still provide enough back pressure. My CAT by pass is 40mm.