tazswing

At the end of the straight this weekend at The Ridge Motorsports Park I was seeing 135F IAT which was more than double the ambient air temperature at the time.

Is this an expected IAT for a MSM? I was getting the car up to 120mph by the end of the straight.

I do plan to wrap the intake, just before the throttle body, in reflective heat tape and I have already wrapped up the radiator hose that basically sits on the intake. I feel that the IAT is picking up radiant heat from engine compartment that is soaking the metal intake body vs this being the actual air temps. It is just hard to believe that the Fab9 FMIC can't cool the air charge more than this.

Begi "cold air" system
Fab9 FMIC (smaller of the two)
Stock MSM turbo
~190rwhp tune
vented hood, some radiator ducting,
larger radiator

patsmx5

iTrader: (16)

I hope people that actually track their cars will post here. I've asked, and nobody that tracks there cars would post there AITs.

I have only drag raced my car, but with 28 PSI, I had +100*F over ambient crossing the line.

Question: Is your AIT sensor open or closed element? Where is it located?

I tested a GM Open element sensor and I could heat the back side of the sensor with a heat gun and it didn't affect the air temp reading inside the pipe. It's virtually immune to heat soak in the engine bay from my testing.

tazswing

The sensor is located in the metal element of the intake just before the throttle body.

Stock photo from Begi's site but my sensor is on the other side:




That gives me a good idea: I am going to put a heat gun to the back side of the IAT sensor and see how much and how fast it changes. The sensor itself may need to be wrapped-up with rest of the intake.

The sensor is what Rev. sent me, which I think is a Bosch not a GM.

Itty

Not to sidetrack, but is that The Ridge Motorsports Park in Shelton, WA? That's a pretty cool little track. I've never driven there, but we actually had a bike race there last year.

patsmx5

iTrader: (16)

Well if it is affected by engine bay heat, best solution is to just put a sensor that isn't. Second best would be to move the sensor out of the engine bay, closer to the intercooler exit. I don't think wrapping it will really fix it, only delay how long it takes until it heat soaks if the sensor is affected by engine bay temps.

tazswing

Yes. Very fun track. That and Oregon Raceway Park are the two like to visit. ORP is in the middle of friggen nowhere, though.

Yeah, I was thinking about getting a coupler that I could tap closer to the FMIC outlet but I actually worry about producing an erroneous reading the opposite direction.

Test and tune, test and tune...but it would be nice to have a target.

Itty

I'll have to take my car there someday... when it's ready.

Based on the rate of speed the air enters the engine under full throttle, I wouldn't be worried in the slightest about air "warming up" between the intercooler and the intake manifold. Heat soak is a much bigger issue for people around here from what I gather, which is why immediately after the intercooler is the most popular spot.

tazswing

That's a good point, too. I'm going to do some heat-gun testing just to see how much heating that metal up might effect the sensor. Making slack on the sensor line is easy so a new tap at the end of the day would be rather easy.

codrus

IMHO, if your turbo intake air temps are too high then wrapping the intake isn't going to do ****, you need a better intercooler (or better ducting for the existing intercooler).

As for the sensor heat soaking, datalog it and look at the temperature curve. You'll probably see it drop slightly as you come out of the corner and get on the throttle, that's the intake charge cooling it down and taking out whatever heat soak was in it. Then it will bottom out and start rising along with the intake charge.

--Ian

Savington

iTrader: (31)

All the pictures I've seen of the Vibrant/Fab9 cores show no turbulators, so it wouldn't surprise me if they don't pull that much heat out. I ran a Precision core with turbulators in my black car, and I would typically see 25-30*F over ambient running at ~350whp.

Wrapping your intake will do nothing. You need to draw cooler air into the turbo, or cool it better once it's exited the turbo. A couple of extra IAT sensors before the turbo and before the intercooler will tell you exactly where your issue is.

tazswing

Wel, that sucks to hear.

When are you going to offer a FMIC?

patsmx5

iTrader: (16)

Really? Is that average, or max temp? So on any given day beating on the car at 350whp on a racetrack, your AIT's were never more than 30*F over ambient that day? Exactly what Precision core intercooler were you using?

Savington

iTrader: (31)

Max temp at the end of a 5th gear 100-120mph pull. Core was a Precision 600hp with restricted airflow. Air temps of 85-100*F, IATs in the 110-130*F. I've posted that data here before. Bigger core, yes, but also a lot more airflow and a lot more boost to contend with. 135*F in 65*F ambient means you're running 170*F IATs in 100*F heat, and that's not what a good intercooler should do.

tazswing

So, this one?

http://www.precisionturbo.net/heat-e...er---600HP/394

Oh, and the smaller Precision is basically the same dimensions as the Fab9...crap, now I want to do head to head testing!

Rallas

iTrader: (9)

With testing I did this summer on my old BEGI Stage 1 intercooler and FAB9 intercooler I could get 40 deg over ambient on the Fab9 and 45 deg over ambient on the older BEGI stage 1 intercooler. They performed very similar for most runs, but after repeated back to back 2nd-5th pulls the FAB9 would peak out at a lower temperature with the same ambient conditions (90-105deg).


I have not seen any guidance that said 35 deg over ambient is great, 35-50 deg is OK and >60 deg is going to cause issues. I even just tried to get some input a while ago to see what the max acceptable MAT is before you begin running into issues. It would be great to get some feedback from the guys with experience. If we had some idea of what the max MAT to shoot for it would help in determining if a particular intercooler is OK or not. I understand that the awesomeness of Sav's old car could do 30-35 deg over ambient, but what does that mean for the rest of us that don't have infinite budgets.

I was testing on 100-105 deg days and saw MAT go as high as 150 deg. I think the OP was asking if the 135deg temp he was seeing is OK. 135 shouldn't be that bad. I am pretty sure I saw 150-160deg when I tracked my 1.8 before turbo and ran the factory airbox. Like Sav said, if you are seeing that much of an increase above ambient you might be ok in the fall winter, but will have issues during hotter track days.


I also run a little MSM turbo and those things aren't particularly efficient when you run it up to 14 psi like I do. The turbo Sav was using in the black car was a ton more efficient and added a lot less heat than the MSM hair dryer would. That is part of the reason he could get such a relatively small increase in air temps over ambient.

patsmx5

iTrader: (16)

Small turbo may be less efficient, but it's moving less air (mass flow of air) through the intercooler too, so the intercooler might have hot air, but not as much of it. A 250whp turbo miata with 280*F air exiting the turbo vs a 350whp miata with 250*F air exiting the turbo, the higher power car puts a larger thermal load on the intercooler. Basically you need to consider how much power the car was making too if you're going to compare one intercooler setup to another. Basically Sav's car was dumping way more heat into the intercooler than your MSM turbo was at 14 PSI, even if your air temps post-turbo were actually a bit higher.

Regarding what's acceptable? I don't have an answer. Cooler is better though. Colder air is more power and less chance for detonation.

tazswing

-Is 130*F IAT okay per say? No real answer, likely not too bad.

-Is doubling ambient air temps okay? Only if it is very cool outside so generally no.

-Is the issue simply a poorly efficient FMIC (e.g., lack of turbulators, etc.), the pre-throttle body metal heat soaking or general erroneous signal for the IAT sensor or some combo there of? Testing needed but some suspicion of the FMIC based on other's feedback.

Thanks, all. This gives me some things to test and think about, esp. just moving the IAT sensor which is rather easy and likely a revealing test.

turbofan

iTrader: (1)

Ian, didn't seem to do it on the dyno. Aside from that, I don't know if it does it when cold, but it definitely is the cam sensor. Hopefully that solves it. If not, then 6500 rpm rev limit all over again.

Savington

iTrader: (31)

The 350hp Precision has excellent internal core design. Lots of turbulators. $305 MSRP vs $175 for the Vibrant/Fab9 350hp intercooler, which should suggest something about function to you. I'll be testing the 350hp Precision IC in my NB2.

My 2871R was definitely a lot more more efficient than the MSM snail, though the power difference more than makes up for it.

sixshooter

iTrader: (12)

A small turbo moving the same mass of air as a large turbo will create more heat doing so. It will usually need to create more boost pressure to move the same mass of air. This is often due to the increased resistance to flow.

Boost is, after all, a measure of resistance to flow of air through the engine and exhaust. And when air is pressurized heat is created. The greater the pressure the greater the heat. Smaller turbos generally create more heat to make the same power.

If the OP is curious if 130F is generally considered acceptable for a max intake temp regardless of other variables then the answer is generally yes, followed by a qualifier. If your spark table and choice of fuels can handle it without detonation at the chosen power level (with a little margin for det resistance) then it is fine. Mine will handle much higher without detonation (track surface temps often over 135F in summer and air temps in the 95F range) so IAT is tough to keep low. I purposefully chose an efficient turbo, conservative spark, and 8.4 to 1 pistons to reduce chances of det.