Hey guys and gals, it seems there is some confusion about COBB's OTS maps and what to make of upgrades. Here are a few thoughts:
1. The stage of the map simply refers to the amount of load, boost, and timing the map will run. The Stage 2 maps will target higher power levels than a Stage 1. So how is that related to the mods list? (read on below ... )
2. The HPFP: The more airflow that enters the motor, the higher demands for fuel. That airflow increase comes from increased boost. The HPFP is a cam driven pump and it will struggle with 16-17psi or greater on the stock turbo. A larger turbo will push it over the edge at lower boost. If you have a very nice flowing exhaust and intake then you will need an HPFP at even lower boost levels ... and on top of this not everyone's car will behave the same. To take the guess out of this, I suggest you perform a test. Load the map that you will run and do a 4th gear WOT run from 3k RPM to redline on a COLD night. The cold air is denser and will stress the pump further. If you see fuel pressure drop in the 1500-1400 psi range under WOT you know it's time for an upgrade. However there is more to this. If the ECU senses detonation, it will pull timing AND richen the fuel mixture. If this is the case, and the pump is on the edge, then it will bring pressure down quickly.
So why do you care about pressure? Well, the direct injection system acts against cylinder pressure when injecting the fuel. The lower the pressure in the fuel system the harder it will be to deliver that fuel and the fuel will atomize and mix with the air poorly. If this happens you not only lose performance, but knock can occur which may lead to the dreaded zoom zoom boom. So my suggestion is to buy the upgraded fuel pump for peace of mind, especially if you have exhaust modifications installed.
3. Now what about other modifications? Well, I will tell you that on the MPS cars the turbo is the largest restriction. So it doesn't take much to "max it out." The biggest bang for the buck in terms of performance will be an HPFP, an intake, a race pipe, step colder plugs, and a custom AP or VersaTuner tune. This will maximize what the stock turbo can do and with high quality fuel and reasonable ambient temperatures you will be close to 300whp (220kw). Having tuned 90+ MPS cars this is what I can recommend for the stock turbo. Remember this is not OTS Stage maps since these are not built for a particular customer car and are more conservative to fit a broad audience. You can see some results in the blog here (
Blog : Stratified Automotive Controls)
In terms of the OTS maps, with an upgraded HPFP you can go ahead and run stage 2 maps. I would only consider the HPFP as the must have modification for running stage 2 ... and in some cases even stage 1.
A downpipe is nice but I would get a front mount intercooler or methanol injection to cool the charge air before going with a downpipe since the gains from timing are more beneficial. After that I would get the downpipe but the gains start to be diminishing.
Also if you have access to E85, with a custom tune, it does wonders in small mix quantities like 25%. You can expect the cars to make 320-340whp (235-250kw at the wheels) and 400 ft lbs of torque (540nm at the wheels) on the stock turbo.
Beyond this you will need a larger turbo.