Sleeper69

I’ve read many arguments on this v-mount setup and it sounds like bullshit to me. I’m wondering if anybody can come up with a plausible explanation for its superiority because I’m just not convinced.

I’m graduating from OSU this may with my bachelors in Mechanical Engineering
Technology and I will be happy to back up any statements I make with technical data.

gingenhagen

my understanding of the v-mount is that it's a compromise. A top mount with a radiator will give you better radiator performance at the expense of intercooler performance. A front mount will give you better intercooler performance at the expense of radiator performance. What point is it exactly that you disagree with? You disagree with it being superior? Superior in what sense?

DragonRx7

Why don't you start with what points you don't think jive?


IMO, just from a strictly legal and cost perspective, it's better that it's set so far back that less people (including cops) are likely to see it and think "Hey, maybe he has something worth stealing (or illegal) under the hood." Also, if you're in a front end accident, it's less likely to be as damaged as a front mount.

First gen man

iTrader: (24)

Reduces turbo lag (shorter tubing).
And a better distribution of the incoming air, between the two.

Sleeper69

I’ve read a couple of thread on the 240 forums speaking of nonsense about static and dynamic pressure. As far as I know there is only one kind of pressure and it’s static. I guess I want to see what people thinks makes it better than a good shroud.

Thats a good point I didn't think of. Im in Oklahoma and we dont get inspected so thats not an issue. Good one.

Sleeper69

I have heard that argument but the problem I have with it is that the temperature differentials are quite large for the radiator but not for the intercooler.

Heat transfers based on a temperature difference and the difference between air from the turbo and ambient air isn't that large when compared to the difference between ambient air and engine coolant. Not to mention that engine coolant cools better than the intercooler air. That is to say that it ejects its heat quicker into the outside air than intercooler air can.

The heat you inject into the air after the intercooler vs. ambient temperature would be the difference between a cool day and a warm day. Either of which your cooling system is able to maintain its temperature at a constant value with a controlled flow rate that is obviously operating under maximum capacity most of the time.

Sleeper69

That’s a point but it’s really relative to individual vehicle setup and I’ve seen these and all different model vehicles.

First gen man

iTrader: (24)

Well on almost any vehicle, v-mount's make it so you can use shorter intercooler tubing.

I like the concept of a V that the air is rushing into, kinda makes more of a parachute
for the air, instead of a big wall for it to hit. (yes I understand there's holes in an intercooler)

With some good ducting, I think it can use the air actually coming into the air damn more efficently than an average FMIC.

Sleeper69

I’ve very seldom seen a front mount with a good shroud on the intercooler. I think it has to do with space. A good shroud actually has the shape of a trapezoid so that when some of the air deflects off the intercooler at anything other than a perpendicular angle it will be caught by the shroud and make a second or third trip.

I still dont think the Vmount would be any more efficient. I think it would be less actually without being shrouded as well. When you make a 3 dimensional shape out of two heat exchangers you need to block the other two exits at the ends as well and make sure they seal well at the their tops.

First gen man

iTrader: (24)

Hold on, none of this makes sense to me.. A trapezoid is going to make my air flow through my front mount at a perpendicular angle everytime? Where would you mount this trapezoid? Please clear this up for me some I don't get it.



Yes, thats common sense. And who is gonna run a V-mount without sealing it all up?

First gen man

iTrader: (24)

I think the real purpose of a v-mount is, like I stated before, to even distribute the incoming air between the radiator and the intercooler. And in my opinion, there is no better way to do so.

fcdrifter13

arnt you supposed to run some kind of vented hood with a v mount. I am sorry my knowlegde on them is little.

As far as the trapzoid thing. Isnt it like you dont want to funnel the air but spread it across the surface of the IC. In simple keyboard pictures like this \ / instead of this / \ front of car is the bottom of the page.

Sleeper69

I pointed out that realistically, distributing the air is unnecessary because of the temperature differences between the turbocharged air and the engine coolant are large enough that the little temperature the intercooler puts into the air before the radiator doesn't affect it. The radiator isn't even cooling at its full capacity under normal circumstances so the added temperature is of little importance.

First gen man

iTrader: (24)

trapezoid is a 4 sided figure with two of the lines parallel, so I'm not sure how that shape would ever add anything to the performance world.

Epitrochoids are cool though..

Sleeper69

Think of the the trapezoid as a reverse funnel with an extremely large hole. You will never be able to force all the air through the intercooler but the air that gets deflected in streams at an angle other than directly back will hit the inside shroud before going back out the front of the car and get deflected once again back towards the intercooler. The intercooler has to be recessed into the bumper a little for this to take place.

Perhaps the V-mount is used because space is short for a proper shroud.

DragonRx7

As far as pressure goes, the static pressure that enters the front of the car would normally flow through the rad and IC and then kinda swirl around the bay and then out the bottom of the car = turbulence. With the V shape and sealed ducting and a reverse scoop in the hood, it creates a negative pressure behind the rad and the IC. The rad's neg. pressure zone being under the car and the IC's zone being above the IC and out the hood scoop.

The way I'm understanding it is that it's essentially like a funnel. The air comes enters at speed A and due to the neg. pressure (vacuum) leaves the area from behind the rad and IC at speed B (B being a faster speed than A)

All this in conjunction should allow it to work better than shrouding from a FMIC to the radiator because the air will still create the turbulance after the IC and before the rad and also after the rad until it swirls around and leaves from the bay.

First gen man

iTrader: (24)

Even if the intercooler was at ambient temperature, it would still block air, and defiantly scramble what actually goes through the air.

It's decently common to need a bigger radiator when you front mount any car.

First gen man

iTrader: (24)

As on any set-up, a vented hood, done right, usually helps.

Sleeper69

The problem with a lot of these assumptions is that air flows like water at these speeds which is not the case. At driving speeds air is already turbulent in nature due to its viscosity. Air's low viscosity gives it a low Reynolds number which is what determines laminar and turbulent air flow. Air streams at this velocity are a product of statistical accumulation of flow paths.

For the air to do what is suggested above the entire system would have to be very stream lined and wind tunnel tested to prove its abilities. You could check the efficiency of a V-mount vs. front mount but it would not be conclusive because the different setup changes so much about the heat exchanger orientation that there we be little certainty as to the cause.

Air flows through a heat exchanger such as an intercooler better than it is given credit for. The majority of the air that hits the intercooler passes through it. When you shroud you are scavenging to add efficiency.

Sleeper69

I dont know that the intercooler blocks air as much as assumed but most people running fron mounted intercooler have aftermarket radiators to begin with mainly as an upgrade. The stock plastic shouldered radiators are lower quality but capable of doing the job. Ive seen many front mount kits running on the stock radiator with no problem.

Monkman33

iTrader: (28)

Front mount + rocks = uhoh

but i really have nothing useful to add.

Sleeper69

werd on that. No one likes their intercooler looking like **** and a front mounted intercooler gets there in a short time. Another good point.

Sleeper69

So far the only verifiable reasons to run a V-mount that I can see are those of simple practicality. Nothing wrong with that but I just wanted to see if anyone could convince me on the technical aspect. I still think its just one big steaming pile of speculation.

classicauto

iTrader: (3)

Temperature difference - temperature schmiference, that isn't the point

If your a mechanical engineer and you can't see ANY possible benefits then, well Im at a loss for words...

The BIGGEST point (temperature differential aside) is that the intercooler while out fron disrupts the flow of air to the rad, that is obvious and indisputable, it IS blocking the rad - barnone, even if air flows through it and remains relatively cool, it still IS being blocked to a certain extent. The V mount cures this.

And obviously, I mean come on - you are a mechanical engineer, you should know that running one setup over the other isn't going to produce magical differences in power, turbo lag or anything else (unless one setup is done COMPLETELY hacked) so this entire argument is moot and a waste of space in this section since the argument is had monthly anyways

And be honest, this thread is not so yo can research the benefits, you are looking for people to make points you can chop down with your degree. If you were truly interested you would have two cars with different setups and go do a bunch of windtunnell testing and report back with your results, not listen to a bunch MORE sepculation and leave your opinion up to it alone.

Sleeper69

I’m not arguing that a front mount doesn't block some air but people are thinking about this completely two dimensionally. Nobody had pointed out the fact that when you increase the volume of the area the incoming air goes into like you do with a V-mount, the air moves more slowly. That’s just an example of one of the factors that’s never been taken into consideration in any of the arguments I’ve heard for it.

The V-mount setup claims to cure a real problem that I have never seen exist in any of my experience using a front mounted intercooler. This would be a big difference if you had overheating problems.

As for the purpose of this thread; I thought maybe I could have something to add to it or maybe give something for others to think about.

Just like you, I don’t have the money for wind tunnel testing to prove or disprove the benefits of this setup. If you had read my previous posts, that’s what I said would be necessary to prove this. I was looking for some substantiated evidence by professionals that had gone to this setup and not speculation. I’m only chopping down the points that sounded like incomplete thoughts when I heard them argued before.

I’m not up to date on the subject and I have read about it in other forums and the rx7 crowd is usually more intelligent so I thought I could get real evidence here.