Genpu: max fmic intercooler thickness ?

About to have an Intercooler cut height-wise to fit beneath my crash bar because where I live the only cores that fit are only 2.5” thick. Would 4” be too thick to fit behind the stock grill ? My options are 3” or 4”.. do not plan on upgrading my turbo for the foreseeable future (but could go BNR s3 eventually hard to predict things)

 

This one (at 24"x6.5"x3.5") fits just fine if you carve up the plastic under tray.

https://www.cobbtuning.com/products/cooling/mazdaspeed3-gen2-front-mount-intercooler-2010-2013

edit: You could def make the 4" fit with a dremel and some time.

 

I don’t think thickness matters as much as height, something like a mishimoto core or sheepey race will require a custom crash bar.

 

There is a maximum effective thickness for intercoolers. 4 inches is probably overkil

 

Evo guys would disagree. Alot of them running huge 4" garret/ets cores making 400 whp on 93 pump gas tdo5h-16gs boosting 30+ psi daily. They swear by them.

 

They might need the flow area I'm not saying you lose power just that there is minimal gain in heat loss with a thicker core

 

Corky bell agreed with the generalization that going thicker is not nearly efficient as going taller, for cooling and for pressure drop. However this is all a generalization as airflow to a front mount as well as fitment requirements to have huge effects on the outcome. As far as the 4" core airflow support goes. The e85 16g guys run 3" cores all day while making up to 450 whp on the 16gs. On pump gas even going from a 3.5" to a 4" core makes a significant difference on max effort 16g evo builds....even though in theory it shouldn't by the generalization. The running theory is pushing the 16g way out of its compressor efficiency on a knock prone fuel (pump gas) requires extraordinarily large and efficient cores to cool the incoming charge in order to make those power levels. I am sure a less restrictive thicker core doesnt hurt either. So perhaps a combination of the two.

 

Yes if you are running a turbo way outside of it's efficiency range and super heating the air then there may be a benefit to a thicker core. But at that point outside of weird scca class rules just get a bigger turbo

 

Well it does make for a very quick spooling and fun car to drive. So there is that. Which makes them great street cars as well.

Lots of variables. For instance there is a big difference between an ets and garret cores and say something like an xs power, cx racing or treadstone. It also matters what your goals are, what other supporting mods you have as well as the fuel you plan to run. However I would lean towards a 3.5" or thicker as a general rule depending on the factors.

 

You can have a very quick spooling turbo and have it push lots of air, look at the PTE 5558 that thing spools quickly and makes serious jam definitely should a balance. Yes its also about where your spool point you want to be is. larger core will add to boost delays as you have to charge it too so there's still a trade-off there

 

Quick spool is relative. But something like a max effort cst4 450whp is going to out spool the crap out of a pte 5558. But the 5558 has made 600 whp on some applications but I personally dont consider it a fast spooling turbo. As far as front mount and turbo lag is concerned it is insignificant compared to something like a cst4 vs a 5558. I actually used to have datalogs on an evo comparing stock intercooler vs a 4" massive garret core intercooler. The difference? 90 rpm. Lol. Granted the difference of a top mount vs a front mount and extra pipping is obviously going to be more than the evo logs comparison but it's not going to be a whole lot more. Just taking a guess maybe 150 rpm or so. Will it be noticeable sure, but wont be as bad as you are implying. Besides if you are running a 5558 or any turbo of that size you should be running a front mount anyways. There is no comparison when it comes to cooling and flow. Fmic wins hands down. There is obviously a place for tmic on smaller turbos but it just depends on what your goals are.