Ram Air Intake

[Matt64341]

I read that the performance gain from better intercoolers would be very good. not something i would attempt to design myself, but depending on price, i would buy it.

but theres not a lot of room to work with between the fans and the timing belt / alternator on the left side...

 

and the intercooler design changed a little in one of the years, 99 maybe? i dont know exactly which year it was but the fitting would have to be changed for older years.

[///BHRpowered]

that is a common myth, you won't really GAIN anything, maybe at hte most 2-5hp, the benefit is that you won't LOSE as much hp as the engine warms up and heat soaks them.

 

I seem to remember them saying around 1800 or so unless they ran into problems, assuming after an inspection it is possible, I was very insistant that if the engine has to be removed that it NOT be done, first of all I don't want that, and 2nd the chance of reconnecting every vacuum line, especially for a shop who has never seen a MCE, let alone many mazda's is 2 great a risk

[Renboy]

Fitting would be the exact same throughout the years. The difference in intercoolers came in '97. Speaking strictly of North America here, the previous years had the intercooler bolted to the intake manifold, and the rest of the plumbing. Whereas '97 and later models were only bolted to the intake manifolds, they used spring clamps to hold the intercooler to the rest of the plumbing. This change was good and bad. Good because there was two less gaskets to buy when removing the intercoolers, but bad because the clamps come from the factory upside down and are a pain in the ass to rotate right side up. Not to mention when rotated up, they tear the hood liner apart.

 

None the less, the install wouldn't be all that hard. There are a few things that would need to be moved/modified, but nothing someone with a clue couldn't figure out.

[Renboy]

2-5hp my ass. I remember reading a long criticism of the stock intercoolers and how ineffective they are. I can't remember the exact details but the temp drop from in to out was minimal. With a half decent system with minimal pressure loss, you would gain a lot more than 2-5hp. Not to mention you could jack the ignition timing to make even more since the mixture would be a lot colder.

[///BHRpowered]

Nope, no real gains, you simply wouldn't LOSE as much power, lets say for arugments sake (and this is not based on anything just a number) that right now your losing 20hp from the stock intercoolers, car is all stock and making 210hp, change out to an efficent front mount and you'll start with 212-215, but then only drop down to say 205, instead of 190, you could argue you've gained 15hp, but not in reality.l

 

install would requite trimming part of the bumper, but it is by no means easy, all the connections are a mild task, but making the custom piping to pump the whole thing, that is the time consuming, and costly part.

[Renboy]

You're just splitting hairs now. By that same theory you don't gain power by adding headers, you simply remove a bottleneck allowing the engine to run closer to it's maximum potential. A power gain is basically the same as the removal of a power restrictor.

 

You wouldn't have to trim the bumper. Replace the stock fans with slim fans and move everything back a bit. If there's a will there's a way.

[///BHRpowered]

No, headers is increasing base line power. YES, the engine is producing the extra power, but your doing something to let it, and the headers will produce constant numbers, when you turn the key and the engine is cold those intercoolers will give you the 210hp, but as it all gets hot your going down, the fmic simply keeps you from losing them, frankly, I see it as more of damage control then a performance gain.

[Graham]

I have always believed that an improved intercooler only gives you a safety margin, but I know that colder air lets an engine produce more power. From memory, every 3 degrees C cooler = 1hp.

 

I've heard of tests with stock (top mount) intercoolers having intake air temps over 70C and this dropping to approx 40C with a front mount. That's a drop of 30 degrees = 10hp gain if the computer handles it (and it should).

 

Biggest difference with the Milly IMO? Superchargers don't add quite as much heat as Turbos. Can you guys confirm - is the SC too hot to touch or is it never that hot?

 

But cooler air is more dense and it will still be at the 14?psi which means it can burn more fuel for more power.

If combining an intercooler with more boost + more fuel you will get real gains. I don't think that's advisable for an MCE unless you have deep pockets, but just an intercooler won't do nearly as much.

IMO not worth US$1800 though.

 

Can the SC be bolted onto a 2.5 engine? That could produce a beast.

[mts]

I wouldn't recommend touching the S/C with bare skin.... looking for blisters.

 

The ABV regulates the boost pressure, and War20B tried to change the boost I believe, and the S/C was making awful noises. There is a way to disable the ABV and make all of the boost go to the engine all of the time. risky though, and deep pockets are needed if it goes bad. I think the S/C will put out around 22 psi at top rpm.

[///BHRpowered]

I don't know if it can be bolted to the 2.5, but there are various S/C and turbo's for that engine that could be made to fit a millenia.

 

your going to have 7psi in first gear, and 14 in all others no matter what, but I would be very impressed with even a 3hp gain, BUT, I would expect to NOT LOSE up to 25hp from heat.

[enginph]

The air coming from s/c is probably very hot and if its cooled down to say 40-50C it would improve things. Anybody have a number about the air temperature after the s/c? MTS or Ren you should have an educated guess.

 

Intercoolers in milly open at 4000rpm! So whatever size i/c you put it will just work above 4000. They are not stupid and they know i/cs are small. But the aim here is a surge of power rather than continuous. At highway speeds when you wanna kick-ass acceleration, you have "stored" cold air in i/cs. Floor the throttle, rev up above 4000 and you will have it. But this is instantaneous, which is not a design flaw since you typically dont hold it above 4000 for extended periods.. At slow speeds if you always rev up i/cs get very hot hence inefficient.

 

With an easy mod they can be made on all the time, which will prolly not cause a CEL (but will cause a code).

[mts]

I have a laser thermometer, I will try and remember to get the actual values on mine... the S/C body, before the IC and after.

 

At 4000rpm, the S/C is probably around 18-20,000 rpm.

[Jdubs99]

The air coming from s/c is probably very hot and if its cooled down to say 40-50C it would improve things. Anybody have a number about the air temperature after the s/c? MTS or Ren you should have an educated guess.

 

Intercoolers in milly open at 4000rpm! So whatever size i/c you put it will just work above 4000. They are not stupid and they know i/cs are small. But the aim here is a surge of power rather than continuous. At highway speeds when you wanna kick-ass acceleration, you have "stored" cold air in i/cs. Floor the throttle, rev up above 4000 and you will have it. But this is instantaneous, which is not a design flaw since you typically dont hold it above 4000 for extended periods.. At slow speeds if you always rev up i/cs get very hot hence inefficient.

 

With an easy mod they can be made on all the time, which will prolly not cause a CEL (but will cause a code).

 

Is this confirmed? I can see maybe some ineffeciency up to this point, but unless there is some type of ECM controlled actuated valve that i haven't seen, I can't see how that would work.

 

[Renboy]

It is actually somewhat efficient to reroute boost. Unless you're running pure septane knock isn't a factor without load. The higher the rpm's the more load there is on the engine. When there is load, the boost goes through the intercoolers to get cooled to prevent pink/knock. At lower rpm's this isn't really needed, and it also saves the pressure drop that naturally occurs with intercoolers. That actuated valve does infact exist, just to the right of the access port above the s/c. It's not perfectly effective though (like I described above). That valve is open up to 4000rpms allowing air to go through the intercoolers, and bypassing the intercoolers and going straight to the intake manifolds. Above 4k the valve closes, and only allows the pressurized air to go through the intercoolers.

[enginph]

If you ever remove the black "do not open" cover you saw it.

 

[MazdaMomma]

[Jdubs99]

Cool, another lesson learned about my car. I'd add this piece of info to one of the stickies.

 

Punch me in the head if I'm retreading this, but the valve is there to manage pressure loss and ensure smooth power across the RPM band. I guess this is my big question.

 

Let's say you can remove that valve, and get the FMIC fabbed up. After the engine reaches operating temp, isn't the drop in intake charge temp going to be greater as an end result in power going to be greater than the pressure drop? I realize the larger common pressure in a single FMIC is going to cause a huge drop in pressure, but ambient temp of the charge should be a dramatic difference from two small engine mounted intercoolers already heated a significant amount. I could be wrong, maybe my sense of increasing power would only matter for a car at speed. Maybe the engine would have drivability issues down low. I don't have the formulas to do the math, and i know there are some other variables involved, but it just stands to reason in my mind that getting the intercooler(s) away from the engine is going to make one hell of a difference.

[///BHRpowered]

No the air going INTO the s/c is cold, or atleast amb temp or slightly cooler, the problem is the tiny intercoolers being in the middle of a heat producing engine, so it really super heats the air once in there. A FMIC would give slightly cooler air from being lower, but not much, however it wouldn't heat up as much, hence keeping you from losing power

[mts]

Here are more pics of it....

 

[attachmentid=782]

 

[attachmentid=783]

 

I was thinking of installing a solenoid valve here that could be activated from the driver's seat to divert all the air to the intercoolers... not sure yet...

 

[attachmentid=784]

 

 

 

 

 

No the air going INTO the s/c is cold, or atleast amb temp or slightly cooler, the problem is the tiny intercoolers being in the middle of a heat producing engine, so it really super heats the air once in there. A FMIC would give slightly cooler air from being lower, but not much, however it wouldn't heat up as much, hence keeping you from losing power

 

 

 

When air is compressed, the friction between the molecules generates huge amounts of heat. That is why it needs to be cooled again after compression. Cooling is relative, if the intercooler drops the temperature 20 degrees it is effective. There is no heat picked up in the intercoolers, the air leaving the S/C is far hotter than the top of the engine.

 

[mts]

Superchargers achieve performance gains by increasing the density of the air/fuel charge within the combustion chambers of an engine. This increase in density is achieved by forcing additional amounts of air (beyond the amount of air that normal atmospheric pressure would force into the engine) at the lowest temperature possible. CFM measures the volume of air that an engine is flowing, while MAF (mass air flow) also factors in the temperature of the air charge, since a cooler charge is more dense and therefore more powerful. So in more technical terms, supercharging increases both the volumetric efficiency of the engine and the mass air flow through the engine to produce gains in both horsepower and torque.

 

Although some manufacturers claim a specific horsepower increase, superchargers actually add horsepower as a percentage gain (percentage of an atmosphere). Assuming an engine with a compression ratio of around 9:1 running pump gas,if a supercharger gives your engine 14.7 psi of boost (another atmosphere) that will essentially double the output of your engine, everything else being equal. After adjusting for thermal and mechanical energy transfer, if an efficient centrifugal supercharger is generating 7.5 psi (approx. 1/2 an atmosphere), you will see around a 35-40% gain in horsepower and torque at your non-supercharged maximum horsepower rpm. If detonation forces you to use an ignition/timing retard system, you will of course see less of a gain because backing off several degrees of timing will greatly reduce an engine's power output. At higher boost levels, the heat generated by compressing air will produce diminishing returns as the boost is increased, although the use of intercooling or racing fuel can avoid this scenario of diminishing returns. Assuming the use of intercooling to run higher boost levels while maintaining reliability, a 100% increase can generally be achieved at around 17 psi on an engine with 9:1 compression running pump gas.

 

Detonation, or engine knock, occurs simply when fuel pre-ignites before the piston reaches scheduled spark ignition. This means that a powerful explosion is trying to expand a cylinder chamber that is shrinking in size, attempting to reverse the direction of the piston and the engine. When detonation occurs, the internal pneumatic forces can actually exceed 10x the normal forces acting upon a properly operating high performance engine. Detonation is generally caused by excessive heat, excessive cylinder pressure, improper ignition timing, inadequate fuel octane or a combination of these. Of the previous, excessive heat is usually the culprit. As an engine is modified to generate more power, additional heat is produced. Today's pump gas will only tolerate a finite amount of heat before it pre-ignites and causes detonation. Although forced induction engines usually produce far less heat than comparable naturally aspirated high compression engines, the cylinder temperatures in intercooled engines are radically cooler yet. It is rarely boost that causes detonation, just unnecessary heat. An intercooler is such a natural solution for forced induction, that in almost every sophisticated application, intercooling is part of the package.

 

For engines that are experiencing detonation problems, the primary options are the use of ignition/timing retard systems, higher octane fuel, or intercooling. While ignition retard systems can be helpful in certain situations, they can also greatly reduce the horsepower output of an engine, as any reduction in timing will reduce horsepower. And while a reduction in timing can save a motor from detonation, the excessive heat which was causing the detonation is still present. Intercooling, on the other hand, actually removes the heat which causes detonation, and allows higher boost levels to be safely run with full timing on pump gas. This produces the maximum benefit in terms of both horsepower gains and engine protection, without any additional maintenance or hassle.

 

Assuming a properly tuned system, proper oil change and engine maintenance, and similar driving, supercharging generally will not shorten the life of an engine, just as is the case with OEM turbocharging (with proper cooldown for turbochargers. A cooldown period after driving is not necessary with supercharging). This is especially true of centrifugal supercharging, which generates boost in line with engine rpm, unlike roots and twin screw blowers, whose low rpm boost can place additional strain on the engine and drive train.

 

Superchargers can be used with automatic or manual transmissions and will not increase transmission wear under normal driving. When racing, however, the additional torque provided by supercharging will place additional load on the transmission, especially when increased traction is present, such as with slicks. This impact is minimized when the boost increases with engine rpm, as is the case with centrifugal supercharging and turbocharging.

[mts]

Interesting read...

http://www.bellengineering.net/Pages/produ...percharger.html

 

http://www.gadgetonline.com/Super.htm

 

http://en.wikipedia.org/wiki/Supercharger

[Graham]

I just read an article on autospeed about the different types of superchargers, recommended as a bit of extra info with the above.

 

MTS, in the message you posted, estimating power gains, it didn't take into account the effort required to drive the supercharger.

A long time ago I read/heard that the engine can be using up to 60% of it's original power to drive the supercharger.

If this was true, then even if the forced intake from the SC was doubling the original engine's power, you'd only have a gain of 40%.

 

But it was many many years ago that I heard that, it was probably BS then and I'm sure superchargers have become much more efficient, but still they do sap engine power to operate.

 

G.

 

wow "SC 101" = my 101st post

[enginph]

Excellent writeup MTS. I dont think milly s/c consumes that much power. It is the most efficient type and there is complicated ABV system that we deal with the leaks of 21-feet hoses and makes the system further efficient.

 

MTS why dont you use CAC solenoid? Just unplug the stock control and use your own switch. Mine was broken it doesnt cause CEL and i didnt see any difference after i replaced it.

 

As a side note it is also obvious from MTS' post that with lower air temperatures we can run lower octane fuel, dont know to what extend tough.

[mts]

Since I have been running mid-grade since April or May without issue... and I actually get less O2 sensor CELs then when on Supreme... tells me something.

 

What I want to do is actually bypass the CAC solenoid maybe... so it can be used as designed or as desired.

[///BHRpowered]

I was thinking of installing a solenoid valve here that could be activated from the driver's seat to divert all the air to the intercoolers... not sure yet...

 

[attachmentid=784]

 

What would this achieve?