Intake Manifold Swap: The answers to your questions of late.

[Hornung418]

You should port and polish the heads to complement what you are doing.

This is only a bolt on mod. But if i had the time, to build the motor up I would just buy a new motor and build it up and then swap it in. When I graduate, I'll consider building the motor but for now this should be fine as a DD

I wonder if there are any gains to be seen on the 323i from this.....

Should be a much freer rev to redline and more top-end power. Low end torque should take a minor hit, but not enough that you should see any difficulty passing.

Shark Injector or ActiveAuto. And yes, everything bolts up the same way it came off, even the connectors.

Oh, so all I have to do is chip it? I was expecting to need to remap the air:fuel ratio and swap the DISA Valve function for that of the M54.

[SWISS]

After getting the car up and pulling stuff off to do the shifter and driveshaft service my homie pointed out the exhaust is waaay smaller on the 323i than the 325i. So getting more in by swapping the intake is just going to bottleneck after the exhaust valves. Probably cause them to heat up and burn out.....

[Hornung418]

After getting the car up and pulling stuff off to do the shifter and driveshaft service my homie pointed out the exhaust is waaay smaller on the 323i than the 325i. So getting more in by swapping the intake is just going to bottleneck after the exhaust valves. Probably cause them to heat up and burn out.....

Lame
Well...It's a good excuse to get some headers

[Tom D]

a engine is a basic air pump. if your going to try and squeeze more air in, then you have to get more air out.

be careful when buying headers, many are merely designed for the WOW factor and have nothing to do with performance.

headers are only the start, you have to look at the exhaust as a whole, i.e.; high flow cats, bigger/smaller pipe, freeflow exhaust muffler.

also back pressure plays a big part of the picture. too much or too little, it's all relevant.

[SWISS]

a engine is a basic air pump. if your going to try and squeeze more air in, then you have to get more air out.

be careful when buying headers, many are merely designed for the WOW factor and have nothing to do with performance.

headers are only the start, you have to look at the exhaust as a whole, i.e.; high flow cats, bigger/smaller pipe, freeflow exhaust muffler.

also back pressure plays a big part of the picture. too much or too little, it's all relevant.

Good points.
On my Z3 I had to have the header flanges trued and milled for the egr valve and smog. I used a magnaflow 3" in/out hi flow cat in factory location and spaced the O2 bungs within reason. The rear one had to be moved back a few more inches later as full throttle would throw a CEL. Thing was loud and revved crazy.

[Hornung418]

a engine is a basic air pump. if your going to try and squeeze more air in, then you have to get more air out.

be careful when buying headers, many are merely designed for the WOW factor and have nothing to do with performance.

headers are only the start, you have to look at the exhaust as a whole, i.e.; high flow cats, bigger/smaller pipe, freeflow exhaust muffler.

also back pressure plays a big part of the picture. too much or too little, it's all relevant.

All valid points.
But since I'm not forcing any more air in than the engine wants, merely allowing the engine ease of access to more air, I shouldn't have to worry about this, right? It will takes what it needs...

[Iceman00]

Should be a much freer rev to redline and more top-end power. Low end torque should take a minor hit, but not enough that you should see any difficulty passing.

No. You shouldn't see a power loss at all. Who told you this?

Oh, so all I have to do is chip it? I was expecting to need to remap the air:fuel ratio and swap the DISA Valve function for that of the M54.

No, it's a plug and play swap. With out a tune, which will change the cam timing, and alter your A/F ratios(which is what Active Auto/ Shark does) you probably will not get the full benefit of this swap, or any other mod.

After getting the car up and pulling stuff off to do the shifter and driveshaft service my homie pointed out the exhaust is waaay smaller on the 323i than the 325i. So getting more in by swapping the intake is just going to bottleneck after the exhaust valves. Probably cause them to heat up and burn out.....

No it's not. The E46 323 exhaust is a dual sub 2" pipe into a single 2.5" pipe. The 325/330 is a dual all the way back. There isn't much power to be gained on the exhaust period, much less with dual pipes (with no crossover)

a engine is a basic air pump. if your going to try and squeeze more air in, then you have to get more air out.

be careful when buying headers, many are merely designed for the WOW factor and have nothing to do with performance.

headers are only the start, you have to look at the exhaust as a whole, i.e.; high flow cats, bigger/smaller pipe, freeflow exhaust muffler.

also back pressure plays a big part of the picture. too much or too little, it's all relevant.

Yes and no. You're over simplifying some parts, and not focusing on others. First, back pressure is never good, and second, the most important part of the exhaust manifold would be the collector. Believe it or not, a few inches past the collector, exhaust piping size doesn't matter, though, with too small a pipe you can actually lose power.

All valid points.
But since I'm not forcing any more air in than the engine wants, merely allowing the engine ease of access to more air, I shouldn't have to worry about this, right? It will takes what it needs...

You'll need a tune. Period. Stop making this more complicated than it needs to be.

[Hornung418]

No. You shouldn't see a power loss at all. Who told you this?

You said that the gains would be in the top of the powerband while sacrificing some low end torque...

No, it's a plug and play swap. With out a tune, which will change the cam timing, and alter your A/F ratios(which is what Active Auto/ Shark does) you probably will not get the full benefit of this swap, or any other mod.

You'll need a tune. Period. Stop making this more complicated than it needs to be.

Well we were talking about exhaust gasses affecting drivability...If you really want me to have tune, why don't you buy it for me

[danewilson77]

Iceman saith....

[Iceman00]

You said that the gains would be in the top of the powerband while sacrificing some low end torque...

I don't believe I've ever said anything of the sort. Would you like to source that claim?

Well we were talking about exhaust gasses affecting drivability...If you really want me to have tune, why don't you buy it for me

Your money, I'm just providing you with advice.

[SWISS]

No it's not. The E46 323 exhaust is a dual sub 2" pipe into a single 2.5" pipe. The 325/330 is a dual all the way back. There isn't much power to be gained on the exhaust period, much less with dual pipes (with no crossover)

You say no it's not then cite the differences. How funny.

[Hornung418]

I don't believe I've ever said anything of the sort. Would you like to source that claim?


You're money, I'm just providing you advice.

I thought you said something to that nature on the e46fanatics thread...my mistake.

I'm not trying to ignore your advice, after all, it is I who came to you

[Iceman00]

You say no it's not then cite the differences. How funny.

Listen dipshit, you stated "the exhaust is waaay smaller on the 323i than the 325i" in which I corrected you in stating was entirely untrue. Are the different? Yes, but that doesn't make one better than another. I'll take the lighter single pipe over the dual. Not to mention a M54 exhaust doesn't have a crossover. ( X, Y or H pipe)

[Hornung418]

Listen dipshit, you stated "the exhaust is waaay smaller on the 323i than the 325i" in which I corrected you in stating was entirely untrue. Are the different? Yes, but that doesn't make one better than another. I'll take the lighter single pipe over the dual. Not to mention a M54 exhaust doesn't have a crossover. ( X, Y or H pipe)

Get rid of the 'tude man. Clarify your statements next time. If you contain vast knowledge on the subject, explain it such that everyone who has a middle school education can understand it! I'm here to learn and improve my skill set, but I only have the concept and general idea of this swap. I'm doing this so everyone with an M52tu motor will stop bitching about how "slow" their car is.
I've invited you to help, but you're starting to hinder my process with OT Posts and BS rants.

In other news, I've sourced an M54B30 Intake manifold possibly with DISA intact, from a member on here I've offered $175 for the whole shebang. Should know tonight what the word is on the sale. Turner Motorsports Throttle Body Adapter should be at my door buy tomorrow evening. Making headway.

[danewilson77]

[Tom D]

I'm not forcing any more air in than the engine wants, merely allowing the engine ease of access to more air, I shouldn't have to worry about this, right? It will takes what it needs...

sorry, i should have used the term "flow" instead of "squeeze"

There isn't much power to be gained on the exhaust period, much less with dual pipes (with no crossover)

back pressure is never good, and second, the most important part of the exhaust manifold would be the collector. Believe it or not, a few inches past the collector, exhaust piping size doesn't matter, though, with too small a pipe you can actually lose power.

iceman, i think you need more schooling on this subject. see below

You said that the gains would be in the top of the powerband while sacrificing some low end torque...

here is a "textbook" explanation compliments of the web:

The effects of back pressure

A muffler is an ambiguity in the performance world, as it can have both good and bad effects on power output. Back pressure is essential for peak power in almost any application, even 6000hp alcohol-burning Top Fuel dragsters have some built-in back pressure. Before we begin this discussion, take note that 1 atmosphere is the pressure that air is at naturally (uncontained) at sea level.

During the combustion process, when the exhaust valve is open, all of the compressed (and depeleted) air-fuel mixture spills out from the cylinders as fast as it can, through your exhaust manifold, into your catalytic converter(s), the muffler, and finally out the tail pipe. The problem with this is, just before your exhaust valve is about to close again, your intake valve opens up, allowing the fresh air-fuel mixture to rush into the cylinders. This is called overlap, and one of the things you take into consideration when choosing a cam, because it can be used to your advantage.

If there was no valve overlap, it would be 100% impossible to completely irradicate all of the spent gases from the cylinder. This has a two-fold effect on power output, depending on what RPM the motor is running at. At low RPM, this effect actually increases torque, because the least amount of compression is lost during the intake stroke, and the ratio of intake to exhaust gases is high. Unfortunately, as the RPMs increase, there is increasingly less time to evacuate the exhaust gases during the exhaust stroke, and more and more depleted air-fuel remains in the cylinders when the exhaust valve closes. The motor becomes incredibly inefficient near its readline. A motor designed for high-torque applications, such as towing, tends to exhibit less valve overlap then normal. The type of cam used in this application is often called an "RV" cam, because a recreational vehicle doesn't need horsepower as much as it needs low-end torque to get it moving.

Your car would also run terribly if there was too much valve overlap as well. When exhaust gases rush out of the cylinder, they create a low pressure area in the cylinder and the exhaust system, sucking the intake charge right into the cylinder, and right back out into the exhaust system. This is called scavenging. When that air spills out, so does the fuel it was carrying, so the O2 sensor reports a rich condition to the computer, often causing further decreases in the amount of fuel the computer injects. At low RPMs, this effect is most pronounced as there is sufficient time to suck out a significant portion of the intake charge, reducing torque. As the RPMs increase, however, the extra velocity imparted to the intake charge increases the amount that squeezes into the cylinder after the exhaust valve closes, as the valve closes so quickly at high RPMs that barely any intake charge escapes through the exhaust system.

No doubt you see the dilemna posed to designers when they choose a cam for the motor - the right combination of power must be achieved at the intended RPM range of the vehicle - if this is a tiny four cylinder, which must spin high RPM to make any power at all, you have to design in a higher amount of overlap. If the vehicle is mostly intended for low speed towing, you design in a smaller amount of overlap for more low-end grunt. Overlap is one of the reasons why the four-cylinder Acura Integra GS-R makes 170hp at almost 7000 RPM, and your 3.0L makes 171lb-ft of torque at 2000 RPM.

You can't control your overlap without changing the cams, but the effects caused by changing the back pressure are the same. When you reduce back pressure, it is equivalent to increasing valve overlap, and when you increase back pressure, it is the same as decreasing the amount of valve overlap. That's why some people will say, "you need a muffler for torque", or, "you'll have more high-end, but less torque, if you run straight exhaust". They are right, but a muffler's purpose is to reduce sound output, not horsepower! By reducing back pressure in an exhaust system, you increase high-end horsepower at the cost of low-end torque.

You can compensate for this by increasing the velocity of the intake charge. Increasing the intake velocity has the added side effect of increasing back pressure, because there is more air to be evacuated during the exhaust stroke. Note that if you increase intake velocity past the limits of the exhaust system, the gains you achieve are diminished to the point of being non-existent. That power will be there when you do upgrade the exhaust system, which is why something as simple as upgrading the exhaust system can result in huge horsepower gains.

You can decrease back pressure by increasing the size of your exhaust manifolds, or using separate tubes for each cylinder (called headers). Increasing the size of the exhaust pipe and decreasing its length also helps, as well as installing high-flow catalytic converters and mufflers. Of course, you could just cut them off. Although it is illegal in the United States to remove the catalytic converter in a registered vehicle, the muffler is a different story...

In regards to pollution, people contribute more to the cozy greenhouse by voicing their opinion on muffler removal as actually running a car without one does. Let me explain how the catalytic converter works, and you will understand what I mean:

When combustion is complete, the exhaust contains CO2 (carbon dioxide) and CO (carbon monoxide). Carbon monoxide is the poisonous gas that is formed when combustion does not occur completely and only one oxygen atom combines with the carbon atom. Carbon dioxide is produced when combustion is completed cleanly. Many years ago, engineers discovered that introducing fresh air (oxygen) to the exhaust gas in the presence of catalytic substances (such as platinum), would further complete the combustion process and bond the extra oxygen atom to the carbon-monoxide molecule, turning it into the much friendlier carbon dioxide molecule. For this bonding to occur, the ambient temperature inside the converter must be around 1200-1400 degrees. If the catalytic converter was a filter fine enough to catch little errant pollutants, IT WOULD MELT. Your car would also have no power as it would struggle to push air through the tiny little holes. Stop and think about how big an oriface the tailpipe is, even on a Geo Metro. How ya gonna shove all dat air through a cheesecloth? Huh?

Point is - if your catalytic converter is not a filter, then your muffler sure the hell is not a filter.

[SWISS]

Listen dipshit, you stated "the exhaust is waaay smaller on the 323i than the 325i" in which I corrected you in stating was entirely untrue. Are the different? Yes, but that doesn't make one better than another. I'll take the lighter single pipe over the dual. Not to mention a M54 exhaust doesn't have a crossover. ( X, Y or H pipe)

You call me the dipshit and you don't know how to design a proper exhaust? Having a Y pipe at the merge collectors is a bottleneck for flow. The 325i FACTORY exhaust manifold flows more with it's true dual setup. The 323i uses the backpressure to enhance low RPM torque. You swapped a manifold on your Z3 and you nominate yourself as an expert.

I swapped the engine in mine.

[Tom D]

incidentally,

the dual vanos controls the amount of valve overlap at varies RPMs, by advancing or retarding the cams.

swiss, what did you do with the M42? i swapped one into my E21 and am loving it.

[littlerock323]

thanks for that write up, very informative

[SWISS]

incidentally,

the dual vanos controls the amount of valve overlap at varies RPMs, by advancing or retarding the cams.

swiss, what did you do with the M42? i swapped one into my E21 and am loving it.

M44 actually.

I sold it on C list, it needed a re build oil pump went. Traded the Z in on the 323i. I am going to get another one this weekend though to start Project Z v2.0

[Hornung418]

TomD to the rescue again.
Great info to have in this thread

[Iceman00]

iceman, i think you need more schooling on this subject. see below

I was going to let this thread burn in the depth of hell where it belongs, but I decided to humor myself, and teach you a thing or two about exhaust gas scavenging and back-pressure.

Here you go:
http://my350z.com/forum/7435408-post15.html

[danewilson77]

Iceman......you're so knowledgeable on all this car stuff...

[ame]http://www.youtube.com/watch?v=6pc2k_WGm3U[/ame]

[Iceman00]

You call me the dipshit and you don't know how to design a proper exhaust? Having a Y pipe at the merge collectors is a bottleneck for flow. The 325i FACTORY exhaust manifold flows more with it's true dual setup. The 323i uses the backpressure to enhance low RPM torque. You swapped a manifold on your Z3 and you nominate yourself as an expert.

I swapped the engine in mine.

Are you an idiot? Wait...don't answer that. You are aware of what a cross-over is and does, and that the 325's exhaust has absolutely NOTHING to do with it's power gain over the 323. In fact, I have BMW's technical PDF which says NOTHING about the exhaust changes (the manifolds themselves are actually the same, save for the flanges that bolt to the exhaust). Most of the power gains were from lower friction internals, engine management changes, valve timing changes, and of course a new intake manifold.

http://www.kinmak.com/downloads/doc/...ng/Engines.pdf

Now, on the 323 from the E36, there was a noticeable bottleneck compared to the the other 3 series exhaust. More than likely do to a terrible Y pipe with a terrible merge and exit.

[danewilson77]