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Discussion Starter · #1 ·
Apparently the air that comes through the radiator and enters the engine bay isn't much warmer that the ambient surrounding air. I was thinking why not make an intake that sucks in the air directly behind the radiator? You get a ram-air effect, plus the air shouldn't be any hotter than the air near the hot asphalt that the HotShot intake sucks up. It looks like there's a space for it on the drivers side of the radiator too. What do you guys think?
 

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From what I understand, the radiator is what cools the engine. The cold air is flowing through the radiator to dissipate the heat from the coolant. So knowing that, wouldn't the air from the back of the radiator be hotter than in front of it?
Correct me if I'm wrong but that's my understanding.
 

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The air coming out of the radiator is indeed hotter than the ambient: if it wasn't there'd be no heat transfer from the coolant to the ambient.

Figure that the coolant within a hot engine is somewhere in the 200oF range. It follows that the water entering the radiator will be about that temperature. I don't have data on the thermal gradient across the radiator under the many varied operating conditions, but it's safe to say that the air coming out of the rad has a significant heat content under equilibrium conditions (that is, the engine is hovering around 200oF, neither heating nor cooling significantly), regulated by the thermostat and cooling fans. I will guarantee you, even in the absence of instrumented testing, that the air a HS filter is exposed to, even "near the hot asphalt" is cooler than the blast-furnace conditions under the hood directly behind the radiator.

As well, the radiator makes a good diffuser, negating any ram effects that might be had by locating an intake behind it. As the air passes through the tiny slots between the fins and winds around the tubes, it loses considerable velocity, crucial for a "ram effect".
 
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Discussion Starter · #4 ·
So that's why you asked about the rad temps in the post below. Well, for this situation I would not recommend putting your intake right behind. The air is somewhat warmer, albeit not hot, but still not what you want for intake. Now if it can be routed in FRONT of the rad....
 

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I have a 93 mx6 v6 its an auto tranny and most of u gys know that a cold ait intake doesnt fit in there that goes to the bottom, since my father is a mechanic we found a way the piping is only 2 inches but its better than just a filter. There is a spot in front of the battery and what we did is we cut the metal and stuck the poiping down there so that the filter sits behind the driver side foglight. the piping goes from the MAS senodr it works good but when u open the hood that little box on the right thats attched to the radiator we had to remove and make something else cause it was in the way the piping would not have gotten down there
 

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rad fan air is hot, do not use this air unless you want a slow car. here's a simple and cheap CAI. Ractive shielded filter slips right over the VAF. Flexible aluminum dryer ducting 4" diameter from the filter down to the splash guard. Secure the ducting so that it faces forward and wedge it between the opening in the splash guard. Total cost <$50 for a ram air CAI.
 

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in case anyone wants to know... its not too hard to put a 160 degree t-stat to lower underhood temps. if your satisfied with them already, or have the stock airbox, advance your timing after the new t-stat. good for pulling a few extra ponies...
 

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I've never dealt with timing before. Is it difficult to advance/retard the timing? Is this something better off left for a shop? How much extra hp are we talking about? Is it noticable with daily driving/quick starts? My racing days are over and I would like to add alittle more pep if possible?
 

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k im guessing you have a 6 so i cant really help you...well...maybe... ok at the distributor, there are 2 bolts that hold it in. loosen them both and rotate the entire distributor assembly while the engine is running and while checking the timing with a timing light. and your distributor is different than mine so... things might be a lil different... you will probably notice it but not by much. like hollowing out the cat. maybe 5 HP
 

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the cat. will make it louder. i have done that to mine and notice a very small increase in power if any. but i dont know i thik it might lose torque with out the bask pressue. later
 

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MX-6 BOY jr said:
running a colder t-stat actually will make your computer think it is hot all the time.
explain...
 

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colder t-stat is a bad idea, this lowers the mean operating temp. Engines have an ideal operating temp for proper fuel atomization etc. Also reads engine temp for fuel ratio, ie. start up vs. warmed up. Using a colder t-stat will just cause the cooling system to run more often. If you want to improve cooling efficiency (narrowing the range of engine temps while maintaining mean temp) get a more efficient rad or use Redline water wetter.

Timing is self adjusting, advance is not very likely. Computer will just retard any advance you may have set, depending on knock-sensor.
 

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dj petey said:
Engines have an ideal operating temp for proper fuel atomization etc.
and that temp is below 160F.

Also reads engine temp for fuel ratio, ie. start up vs. warmed up.
from what i understand from changing them on NUMEROUS cars, the t-stat is a mechanical device. it has no electrical properties whatsoever. thats what engine coolant temperature sensors are for... and the computer only retards timing when the knock sensor says so... you could probably get 4-6 degrees without triggering it.
 

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JspecMX-6 said:
and that temp is below 160F.
Not true. Engines actually prefer to run hot. In fact, as the temperature goes up, things like piston-ring friction go down.

However, there are at least a couple of problems with high operating temps:

- higher engine temps increase the temperature of air passing through the intake, heating it more reducing its density
- higher running temperatures can also incite conditions that may lead to detonation or even pre-ignition
- higher under-hood temps are hard on the vacuum lines and other goodies under the hood

Running too cool is tough mechanically on the engine:

- cool temperatures mean increased piston ring friction, more wear and higher motoring losses
- the oil may not heat enough to boil off volatiles from blowby, leading to the formation of acids, varnish and sludge in the sump

and the computer only retards timing when the knock sensor says so... you could probably get 4-6 degrees without triggering it.
Since the original poster to this thread (willmx6) has a 93 LS, I thought I'd clear up some confusion about changing the timing on the V6:

On 1993 (and 1994) V6 cars, there are two crankshaft position sensors, one in the distributor and one down by the crankshaft. The one in the distributor, NE1, is used by the PCM when:

- cranking (i.e. the key is in the "start" position) or when the engine RPM falls below 500
- when the TEN (Test ENgine) pin in the Diagnostic box is grounded
- when NE2, the sensor down by the crankshaft, has failed

To adjust the timing, you are required to ground TEN, then turn the distributor till the timing marks read 10o BTDC. When TEN is grounded, the PCM switches to the NE1 sensor in the distributor. When you turn the distributor housing, you are also turning the NE1 and G Hall-effect sensors, thus changing the trigger points (with respect to the crankshaft) as the NE1 vanes pass through it. This appears to cause the timing to change. This 10o BTDC setting is the baseline setting and ensures that the cap tower/rotor relationship is correct and that the NE1 and G sensors are properly phased for their respective tasks. Once the jumper is removed from the TEN pin however, the PCM switches back to NE2 again for crankshaft information.

But the NE2 position hasn't changed. The PCM is receiving pulses from the NE2 sensor exactly as it was before the distributor was moved. The actual run-mode timing parameters are determined solely by the PCM and not by the relative position of the distributor. To make real changes to the spark timing in a 1993 KL03, you'll need to change the PROM. You can get tricky and dial in some offset timing by fabricating some sort of adjustable mount for the NE2 sensor or by re-locating the trigger wheel on the back of the crankshaft pulley, but you won't make any permanent (i.e. once TEN is ungrounded) changes to the spark timing by moving the distributor around.
 

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that was useful... i wonder if its the same for the 4. i konw that the timing is set to 12oBTDC. i wouldnt be surprised if the method of adjustment is similar(if not the equivalent). sooo... build your engine, then advance timing when you get your PROM done. ...or keep the TEN pin grounded...j/k 8D
 

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JspecMX-6 said:
that was useful... i wonder if its the same for the 4. i konw that the timing is set to 12oBTDC. i wouldnt be surprised if the method of adjustment is similar(if not the equivalent). sooo... build your engine, then advance timing when you get your PROM done. ...or keep the TEN pin grounded...j/k 8D
I'm not really sure Jspec, to be honest. The V6 was equipped only with Mazda's MECS-II engine control system whereas the 4 banger was, in variants, equipped with both the MECS and Ford EEC systems. IIRC, the EEC system used the TFI ignition...I do believe that turning the disty on these systems actually does affect the run-mode timing since the pick-up is in the distributor. I think the earlier (93-94) MECS 4-bangers had a very similar system to the V6 MECS (with separate NE1 and NE2 sensors etc...) and as such, operated very similarly in terms of distributor adjustments to the V6.

However, without doing more research, this is pure conjecture on my part. Sorry I couldn't offer more info (my focus, as a KL03 owner, has always been the V6 rather than the 4...)
 
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