So I am slowly working my way up to a VF-22 setup, and I am considering an intercooler. First let me say that I am almost 100% going with a TMIC just to avoid the hassle of the FMIC. So I have been told that bigger isn't neccessarily better and I should do a little math to see what size I need. So this is what I did, using this site:

http://www.turbosaturns.net/articles...er_sizing.html

I take my displacement (122 CID) and multiply it by max RPMs (7000 give or take) and divide by 3456 to get 247 cubic feet of air per minute NA. Assuming 85% volumetric efficiency of the engine, this lowers it to 210 CFM. If I want to run 21PSI at 7K that's a pressure ratio of 2.42, so my actual flow would be 510 CFM. Here's the part I don't understand exactly: I multiply that final flow rate by the "air density ratio." I didn't know where to get this, so I used the article's value of 1.49 for 80 degrees F and 74% adiabatic efficiency. That means I need an intercooler that can flow 765 CFM! (At 6K it's still 656 CFM). That's a big intercooler. The TXS TMIC only flows 635CFM from what I hear. That's why I think the number I calculated must be a bit high. Can someone knowledgeable see if I came to this number correctly?

 

three guys here on Oahu sold their expensive tmics to upgrade to fmics. Do it right the first time.

San

 

Ummm... STi V3s ran VF22s with dinky intercoolers. Your stock intercooler is actually bigger than the one that came on the 22b. If you've settled on a top mount, get a USDM or JDM V7/8 top mount. They flow great and "de-heatsoak" quite quickly. They're also cheaper than every other option at $599 new and ~$400 used.

 

You guys concentrate on drag racing, since you don't get much autocross or roadracing opportunity. those kinds of driving are better served by top mounts actually. Plus, at least 2 of those 3 are running turbos that make a VF22 look like a stock XT turbo.

 

Ordinarily I am drawn towards applying science to applications such as this...but in the case dealing with anything talking about airflow and estimating volumetric efficiency, I usually end up reading a lot and then going with my best guess (I still don't feel like I've figured anything out specifically yet, though.)

All I know is that I have been seeing a general egt decrease of up to ~100 dg F. The normal variable is: how hot does it get while driving up the H2 (a highway that travels up about 900ft towards the middle of Oahu.) I haven't tried any other sort of testing beyond normal driving on the highway, though. I don't expect too much of a difference for drag, but hopefully it will help me the next chance I have at a trackday or such.

I gave my PWR tmic to a drag racing friend with a similar setup to my car, although he had steadily used the stock tmic before, and he didn't see any increase in his et, and his trap actually decreased. (I hope when I try to sell it, no one reads this. Nah, I'll be frank.)

I remember a magazine did a similar subjective review of, I believe, the APS tmic vs the stock tmic. I don't remember too clearly, but if I recall correctly, they pretty much stated that the two were equal in all aspects except the stock was more resilient to heatsoak.

Someone please correct me if I am wrong.

 

The article you were referring to was in SCC, and it was the APS topmount. They never saw more than ~2-3 hp out of it, and that came from several hours of dyno tuning and frankly, normal variance of the WRX. They also commented how the stock IC would dissipate heat far faster than the larger core IC. Both would heat up at a standstill, but the stock would get back down to ambient+30 or so after just 10 seconds above 20 mph, while the big core took much longer.

 

So you really think I could run 21 psi on an STi TMIC? That would save me a few $$...

Someone told me the bar and plate design was better than the tube and fin though...

 

That's not what I was saying and isn't what I'd recommend, but yeah. I think 21 is nearing the limit, though.

 

So what would you recommend?

 

I would recommend the Greddy FMIC (v-spec or rspec? IIRC). Mine was pretty inexpensive and I'm happy with the obvious lower temps.