3.2 Exhaust Modification

[KatoKato]

Hello,

I'm planning on installing a cat. bypass pipe and cone air filter on my stock 3.2L engine.

Would this also require a change in the DME chip so I don't destory my engine in the process?

Thanks for your help,

[MotoSook]

I don't think you'll destroy the engine running a stock chip with a cone filter and pre-muffler, but you will leave a few HP's out in the ether w/o a tuned chip.

Why do you want a cone filter? The stock one flows fine.

[KatoKato]

Originally posted by Souk
I don't think you'll destroy the engine running a stock chip with a cone filter and pre-muffler, but you will leave a few HP's out in the ether w/o a tuned chip.

Why do you want a cone filter? The stock one flows fine.

Cone filter mainly for aesthetics. Makes that part of the engine compartment much less cramped.

Is a pre-muffler the same as a cat. bypass pipe?

Thanks for the input,

[bigrubberjeep]

Look into the Euro premuff that "looks" like the stock one, it will help you pass the visual part of a smog test. Then again, your in Canada. Do you have smog laws over there?

[don911]

I recommend the Dansk pre muffler over the fabspeed. I've had both and like the dansk better.
No problem with the stock chip with a cat bypass/pre muffler. I agree with Souk on the cone filter issue.

[MotoSook]

A cat by-pass is just a straight pipe. A pre-muffler has a chamber with a perforated "liner." The pre-muffler is quieter, and it's suppose to give 8-12 HP over the cat. I'm sure there is some gain with the by-pass pipe, but no one has quantified it...that I know of. It's likely to be very close behind the pre-muffler.

I made my own pre-muffler recently that is even quieter than the Danks or Fabspeed pre-muffler. It has a very throaty sound at idle and filters out the tinny sound of a 911 across the RPM range. I have to wait for warmer weather for performance testing.

[NoLift911]

BTDT--

Not that those mods are a waste on their own - but a strong argument could be made that without a chip you would see minimal gains if any - other than sound.

Unless the engine space is of a huge concern save yourself some money and remove the horn and drill a few holes in the cover. I made a cup style airbox out of my lid in 5 minutes using a table saw. The sound is awesome accelerating in the upper RPM ranges.

Mods need to be done as a package in order to take full advantage of what you spend for them.

DME (Steve Wong)
Free flowing exhaust (Dansk)
Airbox mod (Drill holes or just use cut frame)
Cat-by pass (Fabiani)

The 3.2 will respond favorably to these modifications for a small amount of money.

-Jeff

[bigrubberjeep]

Originally posted by nolift911
BTDT--

Not that those mods are a waste on their own - but a strong argument could be made that without a chip you would see minimal gains if any - other than sound.

Unless the engine space is of a huge concern save yourself some money and remove the horn and drill a few holes in the cover. I made a cup style airbox out of my lid in 5 minutes using a table saw. The sound is awesome accelerating in the upper RPM ranges.

Mods need to be done as a package in order to take full advantage of what you spend for them.

DME (Steve Wong)
Free flowing exhaust (Dansk)
Airbox mod (Drill holes or just use cut frame)
Cat-by pass (Fabiani)

The 3.2 will respond favorably to these modifications for a small amount of money.

-Jeff

I agree 100% for sounds, the airbox mod is the best and least expensive.

[paulgtr]

where are you all cutting the holes in the airbox? does any body have a picture? I have a 3.2 and am interested in freeing up some horsepower.
waiting on a chip and want to do some exhaust modifications.
was also thinking about removing the airbox and going to a mass air flow type from autothority.

[MotoSook]

Cutting holes in the airbox is only for an audible gain...no HP gain. The MAF "upgrade" is little to no gain.

You want a change...get a pre-muffler, muffler and a Steve Wong chip.

[paulgtr]

steve wong? what's the difference betyween his and other folks' chips?
I have been planning to go to b&b headers, but have been told they are of no use on a stock 3.2, is that right?

[Oh Haha]

Hey KatoKato,
I told you these guys would give you more info than you take in!

He and I have been PMing like mad trying to help him out with his wants vs. what will be most cost effective and maybe pass smog testing.
I have an SC so I didn't need to worry about any chips. i told him he needs to be aware of a possible lean condition when changing the exhaust from totally stock.
You all with the DME cars will be more help than me.
Thanks,
Wayne

[Porschekid962]

search steve wong and this board and see what comes up.

[MotoSook]

I know someone who had a BB exhaust system on his very clean 3.2 and he sold it all! He went back to the stock headers with a pre-muffler and Steve's chip.

Search "Steve Wong" and you will have plenty to read.

[Wil Ferch]

coupla things:
- don't jsut drill the air box cover...completely section it...saw off the lid to only allow a "band" with the clips to remain, so it holds on the filter element properly. Frees up a lot of space. A la "cup" lid.....
- euro premuff will gain 6-8 hp. Straight through pipe is closer to 0 hp gain( say 0-3). Bruce Anderson's book talks a bit about this...

Wil

[Wavey]

Originally posted by Souk
Search "Steve Wong" and you will have plenty to read.

No *****.

[MotoSook]

Wil: it's been a long time since I read BA's book, and it was before I owned a Carrera, but if removing the restricton (cat) and adding a premuffler can gain 8 HP, one would think the by-pass pipe has some gain (allows for more free flow than with the cat). Can you quote BA? I don't have my book handy.

Edit: Dave, watch it...I might revoke some of my free Guinness offers! )

[NoLift911]

Right Wil - that is the best way to go

I think Bruce Andserson's book is good but a little misleading in terms of results if I remember correctly...

I would like to see this for a totally stock unmolested 3.2 84-89

Stock dyno run get a baseline.

Add DME get dyno result.

Back to stock then do airbox mod (I think I remember he said even without a filter this yielded little or nothing at all) get dyno result

Back to stock do muffler mod, get dyno result.

Back to stcok do cat-by-pass mod, get dyno result....

Then try them together sequentially and finally all at once.

He just kept dynoing things with other mods if I remember right which was confusing.

All that said I think without going to headers you leave roughly 5 hp on the table with the above mods in place...alone I have no idea as it was not done that way.

Clear?



-Jeff

[jbrinkley]

someone asked

[Wavey]

Originally posted by Souk
Dave, watch it...I might revoke some of my free Guinness offers! )

Hey, I was just agreeing with you, pal. He'll definitely have plenty to read!