It makes complete sense that if you go to a lager intercooler you will increase the amount of turbo lag. In my opinion the response time of the stock setup was perfect. It was very quick to respond and I loved it.

Now before I get to my question I will explain my current mods and future mods.

Current.
Fresh rebuild w/ small street port
3 inch dp
Pfc
Racing beat exhaust w/high flow cat
Intake
Boost controller
Water/meth kit 50/50
Fliudyne rad
Large after market intercooler with proper duct (stock mount) intake temps are around 50 degrees
Stock turbos sequential

Future mods will be
BNR stage 3 turbos sequential
Wide band
Larger injectors
Thermal protection (wrap or what ever)
Water meth 25/75 or 100% meth.

My goals for the car is complete street drive ability, like stock but faster.

So my question is....
will the future mods increase or decrease the turbo lag? Will the newer turbos hit sooner and compensate for the larger intercooler? I know the stock unit is not efficient enough. Should I go for a medium sized unit?

What else can I do to bring the response time back to stock levels?

 

Turbo lag and boost response arent quite the same thing, but often interchangeable as far as what you feel. With larger single turbos you may never achieve quite the same amount of response as the factory setup, but there is alot you can do to help minimize lag and increase boost response. With sequential BNRs and a good quality SMIC, I doubt you will see any negaitve difference in boost response. Size of the intercooler isnt everything when it comes to flow, there is alot to be said of the construction of it. A smaller IC may actually be more restrictive than a larger one depending on alot of variables. You are definitely on the right track though, just make sure you have a good sealed system (no exhaust leaks) thermal wrap will help keep the heat in and velocity up. I would also recommend looking at some sort of thermal barrier for the LIM to keep intake temps down as much as possible.

 

it is the longer piping of FMIC's that can make a noticeable drop in response

 

Even breathing out the exhaust (including porting) can have an effect on response, but the power you make (similar to the cooling achieved by a larger IC), are trade-offs you accept. As long as you're talking about sequential stock-based TT's, your response should be pretty good if everything's working correctly.

 

Going to BNR's will have no noticeable increase in lag compared to the stock twins. However, obviously it takes a bit longer to go to 14-16 PSi then it does to 10 PSi but they will hit harder and feel better.

None of the other things will affect response.

thewird