(Q/A thread) SRT-4 Performance Modifications and Upgrade Paths

[Crazyced]

Quote: Originally Posted by NorthNJSRT4

If you're trying to use an FM or S2 WGA on a stock or Stage 1 PCM with the 93tune it's not going to work right out of the box. The 93tune on a stock or S1 PCM assumes that you're using a stock WGA so the wastegate duty cycle is scaled for that WGA alone and PCM WGDC% learning is disabled. But there's a trick to get it to learn the correct WGDC% to operate an FM or S2.

1.) Boost leak test the system, tbolt hose clamp and ziptie all the lines making SURE everything is tight. If you don't have a boost leak tester you will need one to complete this step, just tightening things up isn't enough to be positive there are no leaks.
2.) Run a single vacuum line from the turbo housing directly to the WGA then set the arm so that it boosts to 8-9psi. Keep tweaking the arm until it's good.
3.) Hook the vacuum lines back up on PCM control as stock through the WG solenoid.
4.) Load the factory stock or Stage 1 tune back on the PCM, start the engine at least once.
5.) Reset the PCM by pulling the negative lead off the battery for a minute.
6.) Drive the car around doing some WOT pulls for a while until the boost levels stabilize and become predictable (this is the learning process).
7.) Load the 93tune without resetting the battery.
8.) With the handheld, set up your desired boost level to what you want to hit in 3rd or 4th gear, set up your AFR to your target in 3rd or 4th gear, datalog for knock (adding fuel or pulling timing as needed to make sure ST knock never goes over 1 count).

If you have to reset the battery for any reason, write down your DSP settings and repeat the whole process again from step #4.

If for some reason you just can't get the car's boost level dialed in you can make things easier by getting a rescale tune for the FM or S2 WGA by PMing "Turbo666".

Does it affect boost that much to flash the DSP tune on a 'resetted' PCM?

[NorthNJSRT4]

Quote: Originally Posted by Crazyced

Does it affect boost that much to flash the DSP tune on a 'resetted' PCM?

Without going through the learning process to setup the WGDC% for a WGA the PCM isn't expecting boost can be erratic, not come on as a smooth curve and be difficult to get it to hit a specific boost level every time you go WOT. When you're boosting out of stock sensor range (over 18.5psi) it can make setting up AFR difficult and unpredictable.

[Crazyced]

Quote: Originally Posted by NorthNJSRT4

Without going through the learning process to setup the WGDC% for a WGA the PCM isn't expecting boost can be erratic, not come on as a smooth curve and be difficult to get it to hit a specific boost level every time you go WOT. When you're boosting out of stock sensor range (over 18.5psi) it can make setting up AFR difficult and unpredictable.

Oh I see, I had the stock (or whatever's matching your PCM) WGA in mind.

[scramer05]

Ok sounds good. What would be the process if using an agp? My buddy has his agp off pcm co trol and is just using the dsp for tuning fuel/timing, and so on.

[NorthNJSRT4]

Quote: Originally Posted by scramer05

Ok sounds good. What would be the process if using an agp? My buddy has his agp off pcm co trol and is just using the dsp for tuning fuel/timing, and so on.

An AGP or Kinetic WGA can't be used on PCM control which is one of the many reasons why they suck with a DSP. Even with a CMR dealer's rescale tune, the lowest possible boost level they can hit is the weight of the spring (usually 15-17psi) so there's no way to eliminate the very undesirable condition that is partial throttle overboost which makes the car ALOT less fun to drive on the street.

They were great when we really didn't have any other way to hit high boost targets (I own a Kinetic and an AGP; loved them for years) but since the DSP came out and we gained full control over the PCM they're pretty much worthless now.

[MikeyB_SRT-4]

Is the AGP FMIC you listed the best thing to get on an all stock setup as far as IC's? The reason I ask is that im trying to do the few things im capable of doing myself upgrade wise before getting into stuf that i dont have the time, skill, money for proper apprenticeship, etc. to do.
Thanks

[NorthNJSRT4]

Quote: Originally Posted by MikeyB_SRT-4

Is the AGP FMIC you listed the best thing to get on an all stock setup as far as IC's? The reason I ask is that im trying to do the few things im capable of doing myself upgrade wise before getting into stuf that i dont have the time, skill, money for proper apprenticeship, etc. to do.
Thanks

IMO...The AGP Mini is the best direct fit unit available because of it's end tank design and core. Second would be the Spearco stage 1 then, on a budget, the CX Racing direct fit.

[Boostinfamily]

well that explains a few ( alot of) things.

[Boostinfamily]

correct me if i'm wrong, but with a reset PCM you can still just modify the stock tune and keep the WGDC adaptive learning right?

[NorthNJSRT4]

Quote: Originally Posted by Boostinfamily

correct me if i'm wrong, but with a reset PCM you can still just modify the stock tune and keep the WGDC adaptive learning right?

Correct but you don't get the increased torque output tables (where you get the power increase over stock) or the much more desirable 11.77AFR base point.

[Muffin 69]

If i buy a mopar cat delete downpipe do i need to buy an o2 housing?

[tunerlover3]

You dont have too. You can use the stock O2 housing.

[NorthNJSRT4]

Quote: Originally Posted by tunerlover3

You dont have too. You can use the stock O2 housing.

/Agree

The stock O2 housing is just fine on a stock turbo. Going up to a 3" only gives you a marginal gain over stock and it's a serious pain in the ass to change.

Quote: Originally Posted by Muffin 69

If i buy a mopar cat delete downpipe do i need to buy an o2 housing?

I wouldn't bother with the Mopar one, it's insanely expensive for what amounts to a just a metal tube. If you have that kind of money to spend, a 3" Needswings catless cutout with an electric opener would be alot better for the same money. If you just want a strait 3" catless downpipe, Needswings offers an extremely well made one for 1/3 the price of the Mopar DP.

[director1203]

Nice write up North. Waiting for more to come.

[NorthNJSRT4]

Quote: Originally Posted by director1203

Nice write up North. Waiting for more to come.

The next installments are coming shortly. They'll cover 'final touch' mods for maxing the stock turbo, drag strip mods to cut your ETs and big wheel stockers for those that want a lil' more out of the stock exhaust mani setup.