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

[dohc122acr]

Great job north. I'll be referring people to the thread from now on. You nailed it so far.

[srt4flrn]

I actually had a few questions, I was thinking about getting the MPx BFMIC or the AGP direct fit intercooler but cant decide between which one, but reading your thread it seems that the AGP may be a better solutoin for me, and all my mods are in my sig. Also I dont know if i should get a DSP or not because my buddy has a guy who can custom tune my car and he said he needs a DSP in order to do it. Im mainly getting a custom tune because i cant use the 93 with my AGP wastegate. But do you think I should get the DSP to custom tune it? Do you think it would work? Or should I just take it somewhere to get a custom tune? I was thinking about taking it to turbo666 but its quite a drive from where i am. My goal is o hold atleast 18psi.
Thanks!

[Big_Don]

Quote: Originally Posted by srt4flrn

I actually had a few questions, I was thinking about getting the MPx BFMIC or the AGP direct fit intercooler but cant decide between which one, but reading your thread it seems that the AGP may be a better solutoin for me, and all my mods are in my sig. Also I dont know if i should get a DSP or not because my buddy has a guy who can custom tune my car and he said he needs a DSP in order to do it. Im mainly getting a custom tune because i cant use the 93 with my AGP wastegate. But do you think I should get the DSP to custom tune it? Do you think it would work? Or should I just take it somewhere to get a custom tune? I was thinking about taking it to turbo666 but its quite a drive from where i am. My goal is o hold atleast 18psi.
Thanks!

You wont be able to hold 18psi to redline on factory turbo. You may however spike higher than that but it will fall down to around 15psi due to how small the turbo housing is. If I were you, I would get an OEM wg and sell the agp. Upload the 93tune and call it a day. You will be spiking around 20 psi and you will have better driveability.

[srt4flrn]

well i dont really see why everyone hates on the agp wastegate haha but if i was going to sell it id rather get a stage 2 wastegate not stock, but i dont know where to get one, any ideas? and id be able to use the 93 on that one then right?

[Luis05srt4]

Quote: Originally Posted by srt4flrn

well i dont really see why everyone hates on the agp wastegate haha but if i was going to sell it id rather get a stage 2 wastegate not stock, but i dont know where to get one, any ideas? and id be able to use the 93 on that one then right?

Im trying to do the same thing i have been looking on ebay and craigslist every day and no luck finding a stage 2 wastegate. There was one a couple weeks ago but i passed thinking that my agp was better. Im not going to lie though i like the way it performs . It feels like it holds boost better then stock.

[srt4flrn]

Ya i like my agp a lot too, ive just beend reading up on both and honestly i think im going to keep it because as long as you learn to drive it right and not PTB youll be fine, so i think im just going to get the DSP and get a custom tune, i was also wondering when i get the DSP for a custom tune will i need the 3 Bar/TIP pacakage with it? or the update kit? or just the DSP itsself?

[Luis05srt4]

Quote: Originally Posted by srt4flrn

Ya i like my agp a lot too, ive just beend reading up on both and honestly i think im going to keep it because as long as you learn to drive it right and not PTB youll be fine, so i think im just going to get the DSP and get a custom tune, i was also wondering when i get the DSP for a custom tune will i need the 3 Bar/TIP pacakage with it? or the update kit? or just the DSP itsself?

I Mite just do the same . I have to research some more and find out how to drive it with my agp .

[srt4flrn]

Quote: Originally Posted by Luis05srt4

I Mite just do the same . I have to research some more and find out how to drive it with my agp .

all you have to do is just make sure you dont boost to much partial throttle unless your gonna go WOT just stand on it, but for casual driving make sure you stay lower than 5psi id say, you might have to take it slower in 1st and 2nd gear also but its not that big of a deal, i think the agp is worth it though for just a little bit of getting used too

[rw44]

FM wga. Works with dsp and no ptb like agp.

[NorthNJSRT4]

Quote: Originally Posted by srt4flrn

I actually had a few questions, I was thinking about getting the MPx BFMIC or the AGP direct fit intercooler but cant decide between which one, but reading your thread it seems that the AGP may be a better solutoin for me, and all my mods are in my sig. Also I dont know if i should get a DSP or not because my buddy has a guy who can custom tune my car and he said he needs a DSP in order to do it. Im mainly getting a custom tune because i cant use the 93 with my AGP wastegate. But do you think I should get the DSP to custom tune it? Do you think it would work? Or should I just take it somewhere to get a custom tune? I was thinking about taking it to turbo666 but its quite a drive from where i am. My goal is o hold atleast 18psi.
Thanks!

BFMICs are for cars putting down around 400+ WHP. They take longer to pressurize which decreases your power band and drop some pressure across them which makes causes the turbo to run higher pressure at the turbo housing to compensate (decreasing longevity and increasing charge temp). Unless you plan on going big turbo soon, the AGP direct fit is the best choice.

The 93tune works just fine with the AGP WGA, however it's going to be slower in the 1/4 mile, put down less power than running the stock WGA on PCM control and not self adjust for changes in altitude and ambient air temps. Even with a custom tune you're still going to have to tweak the settings seasonally. An email tune from Turbo666 would be almost as effective as getting a dyno tune from him (a difference of only a couple whp). Full custom tunes are really only of value on a stock turbo when you're running meth, E85 or N20 and trying to push the car to the limit.

Quote: Originally Posted by srt4flrn

well i dont really see why everyone hates on the agp wastegate haha but if i was going to sell it id rather get a stage 2 wastegate not stock, but i dont know where to get one, any ideas? and id be able to use the 93 on that one then right?

The AGP WGA was a good mod back in the day when we didn't have any control over the PCM to make adjustments to the wastegate solenoid's duty cycle. It had it's negatives but being able to run higher than stock boost levels outweighed them. However, since the DSP came out and we can adjust the boost levels however we want on the PCM level you can have all the benefits of the AGP WGA without any of the problems. On a stock turbo there's really no need for an S2 or FM WGA unless you race the car or don't want to get a custom tune to change 1st gear boost levels. I ran 24-25psi on the stock WGA for a long time and only upgraded to a stiffer WGA (the Forward Motion) when I upgraded to a big wheel stocker which needed a little more spring strength to keep the WG closed in boost.

Quote: Originally Posted by srt4flrn

Ya i like my agp a lot too, ive just beend reading up on both and honestly i think im going to keep it because as long as you learn to drive it right and not PTB youll be fine, so i think im just going to get the DSP and get a custom tune, i was also wondering when i get the DSP for a custom tune will i need the 3 Bar/TIP pacakage with it? or the update kit? or just the DSP itsself?

The thing is, why should you have to learn to drive on it when you don't have to? It makes the car a lot less fun when you're constantly worrying about how much boost you're putting it in at partial throttle, looking over at the boost gauge when you should be looking at the road and babying it in lower gears so you don't roast the tires. On PCM control with a stock WGA you can floor it off the line and keep your foot down all the way through every gear. Since the PCM will automatically limit boost-by-gear and RPM to get you traction and not choke the engine the average driver is much faster in the 1/4 mile than running the AGP and having to modulate pedal inputs (which takes practice and skill to do) to stay on the fine line of making good power and keeping the tires from spinning.

Quote: Originally Posted by Luis05srt4

I Mite just do the same . I have to research some more and find out how to drive it with my agp .

See above.

Quote: Originally Posted by srt4flrn

all you have to do is just make sure you dont boost to much partial throttle unless your gonna go WOT just stand on it, but for casual driving make sure you stay lower than 5psi id say, you might have to take it slower in 1st and 2nd gear also but its not that big of a deal, i think the agp is worth it though for just a little bit of getting used too

Casual driving is where the AGP sucks the most. Just trying to pass someone on the highway and putting the car into boost then cutting the throttle to get it out is annoying. It's infinity smoother on a stock WGA to be able to go 3/4 throttle, have the PCM give you ~5psi of boost and pass the person using mostly motor without all the spitting and snarling drama of the AGP that makes you look like you're trying to race everyone (not to mention all the stress you're putting on the turbo by surging it).

[srt4flrn]

alright thanks North, my goal is to max out the stock turbo right now, and i would like to run as much boost as i can, which wastegate would be best for me do you think in order to max out the stock turbo?

[srt4flrn]

because right now im leaning towards getting the FM wastegate and might sell the AGP then

[NorthNJSRT4]

Quote: Originally Posted by srt4flrn

alright thanks North, my goal is to max out the stock turbo right now, and i would like to run as much boost as i can, which wastegate would be best for me do you think in order to max out the stock turbo?

I maxed out the stock turbo on the stock WGA (~24psi with water/meth injection and 26psi on E85). With the custom tune you'll need in the end to max out the stock turbo it really doesn't matter if you choose the stock, S2 or FM WGA. However, that being said, the FM with it's 7lb spring is the easiest for a CMR dealer like Turbo666 to tune for and has the quickest return after a shift without sacrificing any partial throttle usage (like the AGP does).

[tunerlover3]

E85 > meth for maxing out the stock turbo (without using nitrous)

[NorthNJSRT4]

Quote: Originally Posted by tunerlover3

E85 > meth for maxing out the stock turbo (without using nitrous)

They both have their advantages and disadvantages. E85 makes about 5% more power than pump+meth but you lose around 30% range per tank. Depending on where you live it can save you money over 93 octane but by me it's only $0.10 cheaper so it actually costs me more per mile to run. Areas like the midwest that have it really cheap can save money. People that live on the East Coast that can't get E85 locally (like when I lived in NJ) only have the option of running meth. The downside is having to keep the meth tank full, mixing it and storing it but on track days with a couple gallons of C16 spraying straight water from the meth tank it pisses all over E85's power potential.

Personally, I have my car setup to run either. It's just a matter of what I plan on doing. Daily driving is pump+meth 'cause it's cheaper for me (if the price of E85 dropped in Atlanta I'd run it all the time). Spirited driving on the back roads and deserted highways is E85. Track and dyno days are c16 or c23+water for the biggest numbers possible.