FMIC sizes - Page 2

kjewer1 · #16 02-08-2009, 02:29 AM

Rather than guess if it's big enough, try to get a TC in the outlet pipe somewhere.

I've seen people use radioshack units that come with displays, etc. If you run speed density and can log the intake manifold temp sensor, that works too. Make some pulls and PM me the numbers and I'll let you know how it's doing. This doesn't take pressure drop into account of course, that would require two pressure sensors or boost guages to check before and after. I don't know what size your turbo actually is, but at 15 psi pressure drop shouldn't be excesssive on that core. That's a little easier to guesstimate than temps.

SilvrEclipse · #17 02-08-2009, 09:21 AM

Kevin - At what point do you need to upgrade the intercooler? I would assume when the temps start to go really high under boost. The only problem is that during the summer here my temps get over 140*F sometimes but ambient is almost 100*F also. In the cooler months it stays down more but still increases.

My last time at the track temp was probably in the mid 70s, off the line intake temps were a little below 100* and were around 135* at the end of the track. On a small 16g at 18psi. All 5 runs had the same starting and ending temps for the most part. Its also an ebay intercooler, 24x7x2.5 I believe. I have been looking for comparisons of ebay intercoolers from name brands but haven't found anything.

kjewer1 · #18 02-09-2009, 03:19 AM

Where is that temp sensed from, before or after the IC? 140 after the IC with 100 ambient would not be uncommon for most popular cores. A 50 degree rise in a quarter mile pass is fairly typical. A good core however, which is huge and is going to cost you real money, might pick up 15 in a quarter mile, in comparison.

SilvrEclipse · #19 02-09-2009, 06:56 AM

The temp sensor is about 3" in front of the TB.

kjewer1 · #20 02-10-2009, 12:55 AM

Cool. So my previous information is relevant to your situation. Picking up 40 degrees in a quarter mile run is normal, is that how long it takes to get to 140 or was it a single gear pull?

You won't find much info online, you're better off doing your own testing. Which of course costs time and money.

SilvrEclipse · #21 02-10-2009, 07:41 AM

The temps get up that high in a one pass. Ill post a log of the run when I get home so you can see what Im talking about.

SilvrEclipse · #22 02-11-2009, 09:17 AM

Here a pic of my 5th run. I let the car cool some in between runs also. The white line at the bottom of the log is the MAT sensor.

http://i189.photobucket.com/albums/z...g?t=1234365341

kjewer1 · #23 02-11-2009, 02:14 PM

Wow. So this is a case where I'm inclined to say the IC is underperforming more than the peak number would let on, based on the shape of the curve. The IC usually acts as a heat sink primarily, and then a heat exchanger. This one seems to have very little heat sink capacity, since you have an over hand curve there, which tells me that the temp actually rises faster than what you see there, and as it levels off, that's just the sensor catching up to actual temp (all but the most expensive and delicate TCs are quite slow). Normally with a good IC you see an under hand curve, in other words, temp stays lowerlonger and then starts to ramp upwards, as opposed to yours that spikes quickly and starts to level off.

To try to illustrate, a typical 24x12x3.5 Garrett core on my EVO would pick up 20 degrees from a stop to the top of third, but then be at 50 degrees total gain by the top of fourth. Slow rise initially, spiking up at the end. To continue the exercise, going to a 24x13x4 garrett core resulted in 0 degrees rise by the top of third gear, and 14 by the top of fourth. So this maintained its heat sink capacity for a very long time and all of the temp gain happened in 4th gear. This was at 25-30 psi on a maxed out 50 lb turbo. But now I'm rambling, you get the idea. I think you might benefit from a better IC.

david-b · #24 02-11-2009, 02:48 PM

Quote:

Originally Posted by kjewer1

Wow. So this is a case where I'm inclined to say the IC is underperforming more than the peak number would let on, based on the shape of the curve. The IC usually acts as a heat sink primarily, and then a heat exchanger. This one seems to have very little heat sink capacity, since you have an over hand curve there, which tells me that the temp actually rises faster than what you see there, and as it levels off, that's just the sensor catching up to actual temp (all but the most expensive and delicate TCs are quite slow). Normally with a good IC you see an under hand curve, in other words, temp stays lowerlonger and then starts to ramp upwards, as opposed to yours that spikes quickly and starts to level off.

To try to illustrate, a typical 24x12x3.5 Garrett core on my EVO would pick up 20 degrees from a stop to the top of third, but then be at 50 degrees total gain by the top of fourth. Slow rise initially, spiking up at the end. To continue the exercise, going to a 24x13x4 garrett core resulted in 0 degrees rise by the top of third gear, and 14 by the top of fourth. So this maintained its heat sink capacity for a very long time and all of the temp gain happened in 4th gear. This was at 25-30 psi on a maxed out 50 lb turbo. But now I'm rambling, you get the idea. I think you might benefit from a better IC.

So, would a thicker core or a wider core be a better heatsink? I have a small FMIC on mine (stated in 1st post) so I could imagine how badly that's going to be when I upgrade and raise the boost.

Lastly, now that I'm thinking about it. Would having more items behind the IC cause problems? Say for example you have the A/C Core, radiator and fans directly behind the IC. Would those actually slow down the rate of heat disapating from the IC because the air has a harder time flowing by each unit (and also usually being warm also)?

kjewer1 · #25 02-11-2009, 07:45 PM

I expect heat sink capacity would have more to do with mass and inside surface area than with dimensions. Ambient flow through the core is important, but from a heat exchanger perspective, not heat sink, naturally. Both need to be taken into consideration, depending on what you use the car for.

SilvrEclipse · #26 02-12-2009, 01:13 PM

Damn so my intercooler sucks. I guess the cheap ebay intercoolers aren't very good for making lots of power. I guess I will have to invest in a better intercooler this summer.

LandoAWD · #27 02-12-2009, 02:08 PM

Quote:

Originally Posted by SilvrEclipse

Damn so my intercooler sucks. I guess the cheap ebay intercoolers aren't very good for making lots of power.

Depending on which core, I've seen guys in the 5xx to 6xx WHP range on them. Then again, I'd wager that is a miniscule sample of Ebay users overall.

SilvrEclipse · #28 02-12-2009, 04:50 PM

Kevin - What intercooler do you run on your cars? Or which would you buy if you were me.

kjewer1 · #29 02-12-2009, 06:22 PM

That's a very difficult question to answer. So many variables around packaging alone make it impossible to even know where to begin...

The RWD runs an Ebay core, 24x12x4 inch roughly, and it sucks. I went 8s on it, but there's probably another 50 whp on the table. The EVO ran the two cores I mentioned previously, both work quite well, with the 4 inch unit doing VERY well (Buschur sells kits with this core, and I think ETS or AMS does a well). The 3.5" example was an SBR/Kinetic kit.

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