Quote: Originally Posted by
andre81400 
apexi neo
walbro fuel pump
rippmods returnline
boomba fuel rail
750 rc injectors
ss autochrome 3" turboback exhaust
injen intake
ultimate coldside hard pipe with hks bov
tien ss-p coilovers
apexi turbo timer
act street disk clutch in about two weeks
(with stock intercooler) how much hp will i gain with big front mount
oh my dyno numbers are 287 whp 330 tq
First, if you're on a stock turbo why in the world do you have 750 cc/min injectors
that flow 30% more fuel than stock '04+/S1 injectors when you aren't moving significantly more air since you're still on the stock turbo? You can sort-of get it to work, but installing injectors that are
way too big and then having to drop fuel pressure and pull fuel with a piggyback (and therefore jack up timing advance) isn't the best solution to needing a little bit more fuel on the top end when you try to max out the stock turbo. If your drivability is perfect and you've tested your setup and
know it's running safe (air/fuel, knock,
EGT's) under
all driving conditions and have tried something like stock injectors and a touch more fuel pressure as needed and made less power maybe it's running decent, but I've seen too many people over the years go way off the deep end on adding fuel (which is needed when you really crank up the stock turbo) and then have a ton of issues trying to get it to run somewhat decent. And I'm not talking power alone.
Sorry for the rant but there's a ton of new SRT-4 owners who are taking things that other people have done (like adding way too much fuel and then trying to compensate with a piggyback or worse, a MAP clamp) and are assuming it's safe or the "best" way to do something just because "that's how everyone else is doing it." Just like it's crazy to see people now advocating things like running S2 levels of boost on bone stock cars or that there's big improvements to porting certain parts when they don't address key other restrictions or things like intakes now supposedly are increasing power and performance on stock turbo cars. The self perpetuating myths are going to kill these cars as they age.
On to the question of a bigger intercooler, don't expect a lot more power but you will get one thing: better consistency. If you install a big front mount (and accept the risks of removing the front cross-member) the increased surface area should allow you to hold near ambient charge temps going into the engine even when you're pushing the compressor of the turbo well past it's peak efficiency where the compressor outlet temps skyrocket. The cooler, denser intake charge will resist detonation/knock better and allow for more consistent timing. For example on 91-octane here on the west coast most stock turbo, stock intercooler cars will see a little knock retard (pulled timing) of a couple to a few degrees on hot days even on a bone stock car. The larger intercooler cars usually have minimal knock retard in comparison even when you start to push the turbo (excluding knock induced because of piggyback/MAP signal alteration effects). On really hot days and under heavy load for extended periods this might give you a few horsepower but more importantly if you run at the track you'll see it be a lot more consistent in how it runs. And a consistent car is easier to tune safely for max power.
The "direct fit" intercoolers on the market usually use a bar-and-plate core that's a little thicker than the stock Valeo's tube-and-fin core. The quality and design of the different cores used will make a
big impact on how well they perform, way more than end tank design, but in general a quality tube-and-fin flows better and the bar-and-plate cools a little better. But keep in mind these traits could be switched depending on the core, internal/external fin count per square inch, passage design, etc. As a real world example many of the Spearco intercoolers which use a bar-and-plate core fow really well but don't cool nearly as well as other bar-and-plate cores.
One thing you'll notice is that because the smaller direct fit unit doesn't have nearly as much surface area it won't cool significantly better than stock and is still going to heat soak. There is diminishing returns the thicker you make a core as the ambient air passing through and scrubbing off heat starts to heat up the farther it passes through the core and eventually becomes saturated. The stock intercooler is not limiting flow on the stock turbo so there's not a big need for an aftermarket intercooler if it can't at least cool better and/or have better pressure drop characteristics. If you had a big aftermarket turbo that is pushing a lot more air flow mass and wanted to keep the front cross-member (crash bar) it might be beneficial, but less so on a stock turbo car.
