Question about top mount vs front mount intercoolers

[sleeper3]

So I was reading up on the issue, and it appears that to maintain the same boost pressure on the intake side, a turbo has to produce more boost in a front mount application than a top mount. At least that's what I read in CP-E's adobe file about their delta core intercooler for the speed6. I'm wondering if that would cause more wear on the turbo and burn it up.

I'm trying to decide between a top mount and a front mount, and everything is pretty obvious as far as core size, air speed, pressure drop, and heat soak go. I'm just wondering about this one. Seems kind of strange, but everyone knows that colder air is less dense than hot air, so as the air passes through the intercooler it's going to lose some of it's pressure due to the cooling process itself. Anyhoo, thoughts?

 

[clos561]

im going to get a tmic upgrade. and eventually get a scooped hood less pipe less lag

 

[AutoXRacer]

You always have pressure loss with a FMIC increasing turbo lag. You're adding so much more volume to fill with air between your turbo and throttle body. According to a thread in the Lounge Forum, there are no substantial differences between a TMIC and FMIC in terms of overall performance for a street car/daily driver unless you are running a big turbo to over come the pressure losses. The advantage of the FMIC is that it won't get heat soaked as the top mount, but the TMIC cools off so quickly that I personally can not justify the install time and headache of installing a FMIC.

Just my .02 cents...

 

[udontknowjack]

little late to the party question....on the other forum theres over couple hundred hits about the same topic.....got the $ and track/race your car alot go with the fmic....just ur daily drive car low on the $ go with tmic....do a little search....atp fmic claim 30-40 whp gain over stock unit with their and sri....thats what im going with atp fmic....also i see u have cpe cai....not many fmic offer now will work with fmic....

 

[happy and angry]

but everyone knows that colder air is less dense than hot air

Then everyone knows wrong.

 

[AutoXRacer]

atp fmic claim 30-40 whp gain over stock unit with their and sri....

WHAT!!! (huh) Can they claim that much power over stock...?
That seems a little exagerated to me...I could be wrong. (huh)

Can anyone shed some light to this...? Is this possible?

Here is something I just read:

What difference does a FMIC make anyways? Seriously I don't know if there is actually a good explanation for it..

if you look at the real science behind it, for all but the highest horsepower applications, there is no benefit to an FMIC over a well engineered top mount intercooler. subaru guys don't make an FMIC upgrade priority one for that reason. you can easily make a ton of power before even needing an FMIC and you'll find that people that switch to those and do nothing or little else first will actually be robbing themselves of power and pressure.

vendors like to sell FMIC kits because normally there are good margins and high prices. people like to buy FMIC kits because, lets face it, they look damn good in that grille. i roll my eyes every time i see someone bicker about an FMIC core not filling the entire grille. if you like blocking air flow to the radiator and condensor, by all means run that huge core. if your car pushes enough pressure and air flow to efficiently fill an oversized core (and stock boost, trust me, it doesn't) then by all means go for it.

most of the FMIC producers out there run smaller cores up front because of smart engineering. turboxs is the only one i can think of that presently doesn't. length of flow path, pressure loss and materials use is alot more important on any intercooler than a big mouth bling core up front.

end rant.

Then everyone knows wrong.

I'm thinking he meant colder air is more dense... (smash) (lol2)

 

[clos561]

i think it meant, 40whp over stock with the intercooler upgrade AND the intake

 

[happy and angry]

I'm thinking he meant colder air is more dense...

I certainly hope he did.

 

[AutoXRacer]

i think it meant, 40whp over stock with the intercooler upgrade AND the intake

Oh, I would believe that... Intake roughly 20-25HP + FMIC 20HP...
Thats what a TMIC yields; 20HP...according to some dyno sheets.

 

[sleeper3]

Then everyone knows wrong.

I thought that right, but typed it wrong. my bad.


anyway, this isn't a "convince me of your views" thread. this is a simple question about wear and tear on a turbo from spooling more pressure to make up for the front mount intercooler. I'm just wondering if anyone has had experience with this.

 

[sleeper3]

who here has been running a front mount for a long time?

 

[AutoXRacer]

I thought that right, but typed it wrong. my bad.


anyway, this isn't a "convince me of your views" thread. this is a simple question about wear and tear on a turbo from spooling more pressure to make up for the front mount intercooler. I'm just wondering if anyone has had experience with this.

There should not be any additional wear and tear if the turbo is being operated under nominal conditions; nominal boost pressures, lubrication, and temp... Along with correct engine timing...

 

[sleeper3]

nominal boost pressures.....

 

[AutoXRacer]

nominal boost pressures.....

Within the efficiency range of the turbo...

 

[sleeper3]

I guess that's what I am asking... I don't have any way of measuring the actual boost the turbo is producing, and I don't know what range I would need to stay in if I could see it.

 

[AutoXRacer]

I guess that's what I am asking... I don't have any way of measuring the actual boost the turbo is producing, and I don't know what range I would need to stay in if I could see it.

I hear ya...

On boosted cars it is very, very important to see what your engine is doing before starting to modify it. And regarding to the efficiency rating of your turbo, you can get that from the vendor...

The one for our stock MS3 turbos is posted some where in this forum...

 

[sleeper3]

I don't think I am being clear enough or something.

I have a boost gauge. I can see my boost pressure after the intercooler. the turbo is creating more boost than that, though, because as the air is cooled, it looses pressure, due to becoming more dense.

The actual boost that the turbo is producing is more a function of the intercooler than the turbo I think, as the computer is reading boost after the intercooler just like I am. The only way I can think of to monitor the actual boost is to install another gauge upstream of the intercooler so that you can see both pressures. I don't really want to do this, as I think drilling/tapping would be involved. just wondering if anyone else has thought of this.

 

[fourthmeal]

Sure, its thought of, but the turbo is well within operational parameters at 15.6 psi. Hell, if you had a more efficient intercooler, one that saved a pound of boost in loss, you'd have virtually the same nominal parameters.

Less pressure drop the better, so get whichever one you want. A lot of FMIC'ers of the MS3 crowd claim no extra lag, which is great to hear. Perhaps the additional flow created by the better design compensates for the larger volume within the system. A little give-take with a little extra take.

 

[Powerslave]

You always have pressure loss with a FMIC increasing turbo lag. You're adding so much more volume to fill with air between your turbo and throttle body. According to a thread in the Lounge Forum, there are no substantial differences between a TMIC and FMIC in terms of overall performance for a street car/daily driver unless you are running a big turbo to over come the pressure losses. The advantage of the FMIC is that it won't get heat soaked as the top mount, but the TMIC cools off so quickly that I personally can not justify the install time and headache of installing a FMIC.

Just my .02 cents...

i read that this is not true, I read that even tiny turbos move like 200 liters of air per second they move sooo much air soo quickly that a few more feet of pipe or a bigger intercooler is compltetley negliable. not noticable as far as the air is concerned, lag etc.. I could be wrong but I read that in an article called "boost myths" in turbo magazine.

 

[sleeper3]

i read that this is not true, I read that even tiny turbos move like 200 liters of air per second they move sooo much air soo quickly that a few more feet of pipe or a bigger intercooler is compltetley negliable. not noticable as far as the air is concerned, lag etc.. I could be wrong but I read that in an article called "boost myths" in turbo magazine.

I agree 100%. the volume of air added to account for piping is probably charged in such a short amount of time, you wouldn't even notice. cost you 2 tenths of a second to take off 3 tenths of a second type thing. Of course, I have no first hand experience, but it makes sense.


more and more, I think I am going to go front mount. I just want to be able to work in the bay a little easier. maybe that's a stupid reason, but whatever. I like being able to see the head covers.