IT'S #&%$ing HOT!!!
 

...and my car runs like shit because the MAF I'm using doesn't have a temp meter.

Does everyones else car run like shit in the hot weather? Everytime the weather gets hotter I have to re-tune.

It was harsh working the track in the morning today, I can't beleive what the afternoon would be like.

Nah, we drive subarus!

It's not so much that we drive subarus... it's that we don't drive DSMs. :P :lol:

I was kind of worried about my car overheating. As a two driver team it had every little time to cool down between runs, but it was fine.

It was fine in the van. :cool:

Werd. :D

I'm using the LS-1 maf.:roll: I didn't know it didn't have a thermometer until my car started running worse with the hotter weather and I looked for a solution on DSMtuners. I thought it just stayed a constant 78* :P

So no one's car's performance decreases with the hotter weather? Just... my... poor.... dsm...:(

Yes, everyone's car loses power in the heat. I honestly can't say how much, but it's especially noticable in any car that requires an intercooler. I want a larger TMIC. TuboXS claims a 20whp increase on the stock turbo (WRX). Plus bigger means more heat exchanging.

MY car doesn't have any noticeable effects but most likely because I am putting so little down to begin with.

No, bigger means more thermal mass to cool off once it gets hot. Large topmounts are not a helpful for autocross. Dig up the backissue of SportcompcatCar where they did the article comparing the bigass APS topmount with a stock one on a modded WRX.

Did they tune for it?

Yeah, I believe they did, I have the issue somewhere, I'll have to look for it. They ended up with the same intake temp, and less HP.

Is that a magazine about Mercury Cougars?

And the Mercury Lynx and Bobcat too!

That's just weird. I'll have to read the article, but as I understand it, in addition to disipating heat quicker, the pressure drop is much less through a bar and plate IC (by 3psi or somthing). Doesn't that make better use of the turbo's efficiency range?

Usually yes, they were baffled by the results, then went into some pretty technical explanation about what caused the results, that I won't even pretend I understand.

Well somebody pretend to understand it por favor, I never got SCC...

I'll go to the garage and see if I can find the issue to scan, but basically the problem was simple. 6 pounds of aluminum takes WAY longer to cool off than 2 pounds of aluminum. Also, the massively thick core actually reduced airflow. So once your IC got hot (like, say, sitting at a red light, or staging for autocross) it would take much much longer for the airflow to cool it off and get the benefit of an IC at all. I can't remember the hard data (they put a few thermocouples on the car with both ICs and dyno'd them and drove them around) and basically found that the larger IC would result in lots of timing being pulled for several minutes after getting moving again, while the stock WRX IC took like 15 seconds to return to within 10-15 degrees of ambient at 25mph+. The heat sink effect works both ways. Of course, if you managed to get your giant top mount cool before starting your runs or your hot laps, then you would benefit from the larger core.

No. The efficiency map is a table that shows at what flow/pressure ratios the turbo will heat the air the least. But putting that less-hot air through a hot IC defeats that. And pressure drop across the IC has no effect on power anyway- the pressure drop comes from cooling the charge. No pressure drop, no temperature drop. One may argue that the tube and fin style of Ic is more restrictive, but the added cooling benefits outweigh it, both in my opinion and that of almost all manufacturers.

So it wouldn't really be effective (a top mount) unless it was constantly kept cool, like with an IC spray? Or a bottle of water dumped on it before racing?

All this on a stock set-up of course.

I would agree with this. I believe the proper intercooler [size] to get is the one you're making just enough power for. I have my huge greddy FMIC and I wish I'd had gone with something smaller. Too late now I guess...

Sell it duh.

Actually it's a moot point on a front mount, because it doesn't heat soak. Bigger still isn't necessarily better though, because anything bigger than you need to get your charge temps back within 10-15 F of ambient is just adding system volume and lag. But, the overall losses from an oversized front mount are less than an oversized (and heat soaked) top mount.

The real problem with the APS intercooler seems to be core thickness, and the bar-and-plate construction actually. Making an IC with more area is a good thing, but the core thickness made it flow less well, and the added mass (partly thickness, partly due to core type) defeated the purpose of the larger core. The best IC for Subarus with moderate turbos (medium-sized GT30 or smaller IMO) is the JDM v7+ TMIC, but the USDM is only a bit smaller. Hence the lack of upgraded topmounts in SECCS on STis, for the most part.

It is supposed to be 89 tomorrow, with a chance of rain in the afternoon. The record was set in 1970 at 90'. just thought I'd share that. :)

FMIC's can also heatsoak, but just probably not as often as TMIC.