# Question on 01 330ci exhaust valve



## Don Juan (Apr 2, 2002)

Does any one know if there is any hp gains/sound on keeping the hydraulic valve from the right tip of the exhaust open? I've read the 330 exhausts are strraight pipes in the inside.


----------



## The HACK (Dec 19, 2001)

Don Juan said:


> *Does any one know if there is any hp gains/sound on keeping the hydraulic valve from the right tip of the exhaust open? I've read the 330 exhausts are strraight pipes in the inside. *


From what I understand, the valve is there so that at lower RPMs you get more back pressure, hence better low end torque and is open at higher RPMs so you get better horse power. I wouldn't dink with that valve personally.


----------



## Don Juan (Apr 2, 2002)

Just curious. On the #46Fanatics forum, a couple members have done it and mentioned a deeper sound and no decrease in performance . :dunno:

See link http://forum.e46fanatics.com/showthread.php?threadid=1966

The comments are below :

wyu
E46Fanatic

My Ride: 2001 330ci
Location: bay area
Posts: 16
330ci Exhaust flap 
Going on the advice of a few member of this board, I decided to disable that little flap that is present on 330's. (the one that closes in lower rpms and opens on higher rpms) You know what? The car seems more responsive! Its also abit louder, but I like it, sounds sporty! So my question is this: Does this really make a difference? or is it just all in my mind?

GoGo_E46
E46Fanatic

My Ride: Alpine 330Ci
Location: Vancouver, B.C.
Posts: 19
I did the same thing (might have even been my advice  ) i haven't noticed any decrease in power at all. I like the little extra exhaust note it adds as well.

__________________
2001 Alpine White 330Ci


----------



## SONET (Mar 1, 2002)

I agree with The HACK. If you put a larger exhaust system on a normally aspirated engine (which disabling the valve essentially does), it takes away from the back pressure that is necessary to produce torque at lower RPMs. All of these ric-ers you see have this problem. They put these massive pipes on their N/A cars (this will add 75HP, almost as much as my huge stickers!), and all the low-end torque is diminished. Sure, it may produce 6 more HP at the top, but the power curve becomes more 'peaky' than it was before - leaving considerably less power at the bottom end.

The increased back pressure may also be helping the catalytic converters work more efficiently. The 330 has a very low emission rating - ULEV. In comparison, the Honda Civic I looked at the other day was 'just' rated as a LEV. If you consider the difference in displacement, that is a pretty amazing accomplishment.

Bottom line: I wouldn't mess with it - it's there for at least one reason, and I highly doubt it's noise reduction. The engineers would have employed cheaper methods if their goal was just to quiet it down. 

--SONET


----------



## The HACK (Dec 19, 2001)

Don Juan said:


> *Just curious. On the #46Fanatics forum, a couple members have done it and mentioned a deeper sound and no decrease in performance . :dunno:
> 
> See link http://forum.e46fanatics.com/showthread.php?threadid=1966
> 
> ...


Not to discredit the original poster of that message, but even he himself wonders if it's just in his mind that the car feels more responsive. In reality, the SOUND that it makes probably accounts for that feeling. I would LOVE to see some dyno figures with the valve active and de-activated.


----------



## Kaz (Dec 21, 2001)

Its interesting to note that according to the ETK, only 330 and 325xi have the valve, and the other models don't. I don't know if anyone (31st330i?) has ever been able to come up with why.

Also, LEV ratings don't seem to do much with displacement, as the Ford Excursion is also a LEV. :dunno:


----------



## The HACK (Dec 19, 2001)

Kaz said:


> *Its interesting to note that according to the ETK, only 330 and 325xi have the valve, and the other models don't. I don't know if anyone (31st330i?) has ever been able to come up with why.
> 
> Also, LEV ratings don't seem to do much with displacement, as the Ford Excursion is also a LEV. :dunno: *


You mean LEV ratings don't seem to do much with FUEL CONSUMPTION. Sure, the Ford Excursion may be an LEV but it drinks gas like a hick through Moonshine.


----------



## Adrian 330Ci'01 (Apr 16, 2002)

SONET said:


> *The increased back pressure may also be helping the catalytic converters work more efficiently. The 330 has a very low emission rating - ULEV. In comparison, the Honda Civic I looked at the other day was 'just' rated as a LEV. If you consider the difference in displacement, that is a pretty amazing accomplishment.
> --SONET *


Civic is actually ULEV. I think it was one of the first to get the ULEV designation. Still doesn't detract from the 3.0's GREAT fuel economy on the HW and relatively good city considering how we drive them. :thumb:

See the spec. in the URL attached.

'96 Civic Pilot.

http://www.hondacars.com/models/civic_sedan/features.html


----------



## SONET (Mar 1, 2002)

I hate to beat this into the ground, but I am finding a [reputable] source that says otherwise.

http://www.fueleconomy.gov/feg/noframes/17558.shtml

The car I looked at was not marked ULEV. Keep in mind that the Civic is offered with at least two different motors.

--SONET

Edit: Removed lousey attitude.


----------



## Adrian 330Ci'01 (Apr 16, 2002)

Weird, the Civic has been ULEV for quite a while. It is currently advertized for the base engine and the lower power (non Si SOHC) VTEC engine.

I don't doubt your intentions to keep us informed but it seems unlikely that Honda of all manufacturers could not design a 1.7 L ULEV engine, and then lie about it.

CHeers,

Adrian.

P.S. Just checked your site (cool thanks!:thumb: ) and you were looking at the 2.0 L engine which I have never heard of. The 1.7L engine is ULEV:
http://www.fueleconomy.gov/feg/noframes/17556.shtml


----------



## Kaz (Dec 21, 2001)

Adrian 330Ci'01 said:


> *.
> 
> P.S. Just checked your site (cool thanks!:thumb: ) and you were looking at the 2.0 L engine which I have never heard of. The 1.7L engine is ULEV:
> http://www.fueleconomy.gov/feg/noframes/17556.shtml *


The 2l is in the new Civic Si, and is also the base RSX engine.


----------



## Adrian 330Ci'01 (Apr 16, 2002)

So to SONET's original point, Honda does make an engine << 3.0 L that is only LEV.

I'll shaddup now..


----------



## 31st330i (Jan 11, 2002)

Don Juan said:


> *Does any one know if there is any hp gains/sound on keeping the hydraulic valve from the right tip of the exhaust open? I've read the 330 exhausts are strraight pipes in the inside. *


it's not hydraulic (liquid or _hydro_ *pressure*) or even pneumatic (air *pressure*). it's vaccum actuated. the vacuum source is controlled (open or closed) by a solonoid which is in turn controlled by the ECU. the solonoid is located inside the trunk bust beneath the left rear tail light. in fact (on a sedan anyway) you will see a small seem in the sheet metal just below the tail light. the vacuum solonoid is just begind that seem. the relaxed position is open (simply sated as "normally open").

that said, the valve's only purpose is apparently to prevent interior exhaust resonance. to the best of my knowledge, the valve is only closed on decel and perhaps cruising. disconecting it will likely reduce your cruising speed fuel economy as well as increase interior resonance and NOT increase HP one bit.


----------



## bmw325 (Dec 19, 2001)

The Bentley's manual concurs w/ 31st330i-- the flap is there to reduce interior exhaust noise at idle.


----------



## Nick325xiT 5spd (Dec 24, 2001)

I have to wonder if there's a way to disable it temporarily. It would e nice to do a back to back comparison. (Yes, my engine is too quiet).


----------



## alee (Dec 19, 2001)

Nick325xiT said:


> *I have to wonder if there's a way to disable it temporarily. It would e nice to do a back to back comparison. (Yes, my engine is too quiet). *


Wouldn't it be easy enough to disconnect the solenoid?


----------



## 31st330i (Jan 11, 2002)

Nick325xiT said:


> *I have to wonder if there's a way to disable it temporarily.*


simply disconnect the vacuum hose at the muffler. screwa a small bolt into the line or shove a golf tee into it. secure it with a tie strap so it doesn't rattle.

you could also cap off the vacuum at the solonoid inside the trunk. you'd need to remove the trunk liner, though, which means that it's more work.


----------



## 31st330i (Jan 11, 2002)

alee said:


> *
> Wouldn't it be easy enough to disconnect the solenoid? *


that would very likely trip a fault code.


----------



## alee (Dec 19, 2001)

31st330i said:


> *that would very likely trip a fault code. *


I thought that's what the obd2 software from the group buy was supposed to solve.


----------



## 31st330i (Jan 11, 2002)

alee said:


> *
> I thought that's what the obd2 software from the group buy was supposed to solve.  *


that's a hack approach and more work in total. just disconnect and plug the vacuum line at the muffler (when the car is cold, of course).


----------

