Persistent Myths

[Siestarider]

Considering this forum is like most societies, myths arise and seem to be persistent in spite of the data. So I am going to lay out a few of my favorites. They are my favorites because I have tried them myself, am a data junkie, and F=MA

1. Bolt-ons can improve HP/T. No, anything bolted on needs a tune adjustment to be effective. No, the car cannot learn to use bolt on power bits on its own, it must have ECU mods to do anything with bolt-ons. The only exception is that bolting on a better intercooler will reduce the times the stock ECU pulls timing/boost in response to stock IC intake temps running too high. Reduce power loss maybe a better way to look at it. Of course, tuning is paramount.

2. Cold air intakes add power. This myth is tricky. 2J intake adds power with tuning. Mountune intake, which supposedly adds a second cold air source to stock intake, does not. Yes, I have logs to prove it. Biggest problem with Mountune is that the lower "cool" air hose end is located in a pressure zone lower than ambient. What it really does is provides a vacuum leak at the air box. That big mouth snorkel may be useful in this regard, but I have not seen the data.

3. Our cars overheat on track, therefore an oil cooler, bigger radiator, or both are required to run stock turbo on track. No, everyone who has spent any effort at all in making sure the intake air actually has to pass a heat exchanger can run stock on track just fine. If the car is not reducing power due to heat, Ford engineers have allowed those conditions. If coolant at 230F and oil at 250F were dangerous, the ECU would pull power at those instead of higher temps.
If you are serious about tracking, both undertray and air dam mods show great promise in reducing coolant and oil temps.

4. Our spoiler/hatch tail is non-functional. Surprise. Pressure data show it applies downforce. Not a lot, but above ambient pressure, so its doing something for us.

Feel free to add your own favorite myths. Its only cost me a few grand and a lot of fun to identify these, plus lots of reading here and on other forums where enthusiasts gather to swap ideas.

 

[Hijinx]

Here's one that can be a little tricky, depending on the setup.

Lag with a big turbo makes for a slow car in-town. This myth makes its bed in people's past "experience" and in budget set-ups. But it's not all myth, here's why: a big turbo Fiesta, when done right, is only 10ths of a second or so behind a "stage 3" stock turbo or a Cyborg turbo to nearly any in-town speed at WOT. I've looked at many logs between my stock turbo, my two Cyborgs and my DHM (in 3rd gear) to come to this conclusion. What I looked for was normal in-town speeds of 20-45 mph. The "donkey kick" may not be there, but the car is hardly slower.

 

[Bluedrank]

2. Cold air intakes add power. This myth is tricky. 2J intake adds power with tuning. Mountune intake, which supposedly adds a second cold air source to stock intake, does not. Yes, I have logs to prove it. Biggest problem with Mountune is that the lower "cool" air hose end is located in a pressure zone lower than ambient. What it really does is provides a vacuum leak at the air box. That big mouth snorkel may be useful in this regard, but I have not seen the data.

I'd be very interested to find out if connecting the mountune or CPE lower tube to a velocity stack routed through the fog light cover does anything noticible. The sektune intake looked really interesting, and i wonder if it would help that lower tube be more functional.

 

[Joker328]

Oh god, we already have one flame war going. Did you really need to kick off another one?

 

[JasonHaven]

I'm all for some consensus being had on various pros/cons of different upgrades. Flame wars or not.

 

[Siestarider]

I almost mounted a NACA duct in experimental undertray tonight so I could try feeding Mountune lower inlet with that. Ran out of time prepping for track day tomorrow. But will eventually get to it. Even if it does not improve pressure losses in intake system, it might work for brake cooling hose.

I used to use 2500-6500 rpm pulls in third to evaluate mods, if delta t does not decrease, you do not have more power. But Hijinks makes a good point. Big turbos produce their mojo at higher rpms, so my technique is too wide an rpm range to pick that up.

I assume flame war is not my bag, so regrets to those having fun with that activity. I used to enjoy arguments, but on an internet forum you don't know who you are arguing with. I just don't see the point.

 

[Bluedrank]

Interesting thought, but I'd be terrified of sucking in rain. These Florida summers would make that setup undrivable I'd imagine.

 

[Wimp Lo]

Interesting thought, but I'd be terrified of sucking in rain. These Florida summers would make that setup undrivable I'd imagine.

I don't see what rain has to do with it, I'm pretty much waterproof so I'm good to go unless there is a hurricane evacuation or something.

 

[Bluedrank]

I don't see what rain has to do with it, I'm pretty much waterproof so I'm good to go unless there is a hurricane evacuation or something.

An intake grabbing air from the undertray in florida just seems scary to me. The car's pretty low as it is. It rains basically every single day in the summer, and it can be blue skies at 1pm and tornado warning at 2pm.

I'd just be too afraid of hitting a big puddle and sucking it all up from the undertray.

 

[Wimp Lo]

Oh, I thought you were talking about something completely different.

I've heard stock airbox with Bigmouth drains water just fine. I'm in California so I don't have to worry about it so much.

 

[Bluedrank]

Nah, another guy in florida is talking about hooking the mountune intake up to a NACA duct in the undertay. I was commenting on how scary that sounds considering the amount of rain we get. It sounds like rain vacuum to me.

 

[RAAMaudio]

I will take a wider power band any day over a donkey kick or laggy setup so I can have power on tap nearly all the time. It might not be as engaging and sometimes not feel as fast as it is but it sure makes it easier to be fast more often with far less time lost finding the right gear or bringing up the revs, in town, or on your favorite twisty road. Being much easier to modulate it will be far easier to avoid time consuming and tire wearing wheel spin, which also gets less attention from those with the authority to write costly tickets.

That said, I agree, under more limiting circumstances, the laggy or big turbo cars can be about as fast as each other in town, just not as fast all around in the vastly varying situations we encounter more often than not

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It would seem logical on a stock turbo or tuned one the stock coolers could be quite effective if all the air passes through instead of around the coolers.

A bigger IC is pretty important and even then sealing them up as well as all coolers is very helpful just should be done.

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I will have to get a 2j intake sometime to test, or make one as I was going to do at one point until I realized when I took the cowl off I did not want that much noise. Of course I worked out a way to reduce that dramatically with using a bit of mat and foam so I might give it a try.

I would then compare it to my grill mounted, large diameter velocity stack inlet, 3" into round filter box(like I have seen on hundreds of race cars) heat shielded over the turbo, etc....system I built. I bet mine makes power and it might even make more than the 2j at least at higher speeds

It would be nice to take more weight off even though my whole system does not weigh very much.

I made it out of odds and ends laying around, only part I bought new was the velocity stack for around $20.

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[airjor13]

Big turbo = better MPG, yes and no. Yes if you are always off boost, no because you will always want to be in boost

But I told my wife it gets better MPG, and it makes merging "safer"

 

[MKVIIST]

This is a great thread and I'd like for it to stay on topic, I've removed a few offtopic remarks. Thank you.

 

[D1JL]

An intake grabbing air from the undertray in florida just seems scary to me. The car's pretty low as it is. It rains basically every single day in the summer, and it can be blue skies at 1pm and tornado warning at 2pm.

I'd just be too afraid of hitting a big puddle and sucking it all up from the undertray.

I would think most of you would think about this a little more scientifically.
Do you realize how much vacuum would be required to suck water up two feet of two inch tubing from the bottom of the air box.
Also how imposable even that would be with the normal air intake higher up in the air box.
Now assuming that we are talking about the Mountune system, the lower hose they supply is porous and therefore could never draw a vacuum strong enough to suck water up.

I have the Mountune CIA and this info is based on fact not fiction or speculations.



Dave

 

[RAAMaudio]

Thanks for putting this back on topic, which is a good one
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Sorry but I have to disagree, at least in theory if not in actuality.

An engine is an air pump, a very effective one, it can also suck up a lot of water until the cylinders fill and bend a rod or two since water does not compress very well. It would take very little water to do so when you consider the volume of the combustion chamber at TDC.

Though I have not dealt with it directly I have seen quite a few posts on different forums over the years about this issue and one of the members here posted about it with a WMI kit that did not shut off or something similar and broke a new expensive engine build.

I was concerned driving my car in a monsoon with a 3" velocity stack inlet in the grill it was really coming down and a lot of spray hitting the front of the car. I do have a drain in the air filter enclosure for this reason, perhaps it saved the engine, perhaps it may not of.

Most likely this happens when driving into standing water which usually means a great deal more issues as well.

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I prefer to play it safe when possible

Rick

 

[D1JL]

Yes, Rick but I am surprised at you of all people, you are still failing to consider two things.
First is the normal air intake that is above the lower tube in the bottom of the air box so water could never be sucked up the lower hose.
Second, as I said the lower hose is and should be porous so air would be sucked through the walls of the tube before water could ever sucked up the tube.

This of course is based on the use of the Mountune CIA.
However using a different CIA that deletes the normal upper intake and uses a non porous tube all the way down to the bumper, well then I defiantly agree with you.

I my opinion, and not pointed at anyone.
I do believe that people should do what ever they want.
I also believe that any extra air input from a cooler source is helpful.
I do however believe it is not correct to instill fears about a product that is not based on fact.



Dave

 

[Bluedrank]

See, I did consider it. It doesn't mean that the idea of it still wouldn't concern me. There's no reason to think down on people considering different issues.

Either way, the real discussion here is whether or not the lower secondary tube used by 2 different manufacturers is actually a detriment, and if so, can that be solved by routing it to the front or underside of the car?

 

[dyn085]

Dave is entirely right, there are no intakes available for the FiST that are of any remote danger to the engine for water ingestion. Short of driving into water that covers both inlets, there is no reasonable fear hydrolock. Air will take the path of least resistance into the engine and with two inlets you could cover one up with water and still be fine.

As for forward-facing inlets, a similar concept applies-water is affected by gravity. Any water that does come into the inlet, which is going to be minimal to begin with, would have to accumulate at a fast enough rate to fill the entire lower box up to the filter before it could even get into the tract to begin with. And the box has at least one drain hole so it would have to accumulate faster than it could drain back out...

It's true that only a few ounces of fluid are necessary to cause damage (I haven't done the exact math offhand to say how much), but you must realize that that much fluid has to enter the cylinder on one single stroke. The difference between a WMI failure that drains excessive fluid upstream of the FMIC while the engine is off, thereby leaving ample fluid available for the engine when it's at its absolute lowest rpm (starting), and a handful of ounces being slowly fed into the intake when it's being rotated at 2500 rpm (assuming a constant speed on the interstate when it's raining)...well, it should be self-explanatory.

The fear is understandable due to perpetuated rumors and stories but the science and math show us that it's unfounded.

 

[Siestarider]

I recall reading somewhere that running heater on track would not help our "overheating" problem. I tried it today when I saw 230 coolant and 250 oil. Heater on full blast reduced temps immediately, 210 coolant and 225 oil on a deliberate hot lap. I logged all my sessions today, need to work the data over as this report is based on visual sample scans of AP at speed on track.