redCORTEX

Hey guys,

I'm at a loss here and want to see if anyone has experience out there. I've got a '13 GT Auto with Boss IM and Steeda tune. I came from a '14 MT with stock IM and Steeda tune. So far, I'm not feeling the pull like I did with my last car. I think that has more to do with the tranny than the manifold but I'm not sure.

I do plan on LT headers, bigger TB and CAI later this year and a Procharger in ~2 years. I'm thinking about going back to a stock IM to remedy the lackadaisical feeling of this car but can't help but wonder if the LT/TB/CAI will make a decent seat of the pants improvement. Also, with a Procharger, are there more appreciable gains with the Boss IM over stock?

Also SERIOUSLY considering upping to 3.55 gears over the stock 3.15. This is a DD(that I drive like I stole it) and I do plan on monthly 1/4mi once I have a bit more done to it (dedicated slicks).

I know I'll get a lot of "It's up to you" but I'm looking for anyone who has similar mods or experience with this situation to input their opinions.

Thanks,

kirk35

I can tell you what I learned with my last car, 2004 GTO (see sig). My choice in mods was similar to yours. I installed headers, then a cam & 3k stall then a Procharger followed by the Edelbrock Victor Jr. and finally P&P heads. The Boss intake has a powerband similar to the Victor Jr., it looks pretty sitting there but kills low end torque. The LT's will also have a little loss in the low end, but not nearly as much as the Boss IM.

Enter Procharger, the centrifugal isn't known for bottom end power, but believe me traction will become a distant memory. The boss intake and headers allow for more airflow which is going to lower your boost level when compared to the same pulley set-up on a totally stock engine. Don't worry because you'll make more power with less boost, remember boost psi is just a measurement of the air that isn't making it into the engine.

The path I would take is to put the stock manifold back on for now, get the LT's skip the CAI since you can't use it with the Procharger and the factory CAI is fine, just not as pretty.

Once you get the Procharger bolt the Boss intake back on and you'll have a beast, the centri's love an engine that can breathe. As far as gears go, once you get the blower I don't think you'll want gears unless you plan on running drag radials all the time. You might want to invest in a good 3k stall and aftermarket trans cooler, way more bang for the buck than any other mod.

scottmach

The Boss Intake only works on an auto with a loose converter and shift points north of 7500. Upping the gears will do absolutley nothing for you. Take it from someone with first hand experience here. If you're not willing to do the two main things I pointed out you'll be better off with the stock intake.

redCORTEX

Thanks for the input guys. I think I'll hold off on the gears for now. I'll probably wait until I have the LT and X-pipe before I do anything just to see if it feels better. Hoping the TB increases throttle response some. If I'm still not happy I may just switch to a stock IM for the time being. That being said, they're super cheap and readily available so I wouldn't be losing anything to just try it. Plus I'd get to turn a wrench.

Any idea if the install kit for the Boss IM (rails and lines) also fit the stock or will I need to pick up more than just the intake and cover?

Thanks,

scottmach

A throttle body will be a waste of money and nothing more than money pi$$ed away. You're concentrating on the wrong side here. These cars see gains on the exhaust side, not the intake sides. Yes it may feel a little better with throttle response but there are better things you can do. Longtubes will help but in the end they're just a band aid for your problems with the Boss Intake. You need a converter. Your stock one flashes to 2000 rpm give or take a few, right where the Boss Intake doesn't want to be.

cruisin5268d

The Boss Intake Manifold really needs some other upgrads to shine and help balance out its pros and cons.

breathegood

For a naturally aspirated application, just about any mechanical modification you make on the intake or exhaust to increase HP will hurt low end torque. It's just the simple physics of how an engine works. Tuners can compensate for this somewhat with software wizardry (some better than others), but only to a certain extent. Intake, TB, manifold, heads, cams, headers, mid-pipes, and cat-backs will all work together to create gains in the high RPMs that are greater than the sum of the parts, but low and mid-range torque generally suffer for it.

The free solution - learn to drive it a little wound up.....I did this with my car when I had CAI, heads, cams, & headers. 5th gear was basically useless, and it took some engine speed to get rolling from a stop. It wasn't the friendliest drive around town (or fuel efficient), but on the highway it sure was responsive (read: FUN AS HELL) in the next lower gear for any given speed. Not really applicable in an auto, sorry.

The not too expensive solution - A new tune. Dyno time and/or a custom email tune from a different vendor may make all the difference in the world. I'd go here before spending $$$ on anything else, including replacing the Boss manifold with a stocker. Ask specifically about auto shift points to get the most out of what you have.

The band-aid solution - gears.....changing out the diff ratio won't actually change the torque curve, it will just get you into the meaty part of the curve at a lower speed for a given RPM.

Forced induction - there's plenty of information on that in the forum, so I'll just say not all FI applications are created equal. On a stock block, a turbo or centri may give wicked results at red line, but may not necessarily resolve the "lackadaisical" feel in casual driving while not in boost. Food for thought.

Displacement and/or Compression ratio - A built motor is the only way (mechanically) you're going to gain significant low RPM torque without FI. A positive displacement supercharger is effectively the same thing as increasing displacement.

redCORTEX

I really appreciate the feedback on different outlooks. I think the above snip pretty much sums up my problem. I was good at driving my '14 MT wound up. It was FUN AS HELL. I think I have to just accept the fact that it isn't the same car. I'm going to keep my general plans but add in some research on a torque converter.

Just have to make time for the track...

Thanks,

redCORTEX

Ok so after some research I came up with the following game plan as I hope to have a ~$3000 budget this summer.

$1200 UCA/LCA/Koni Yellows/CC Plates - Really not negotiable, hopefully you all agree.
$1200 Circle D Converter - I'll talk to Chris to figure out the best one that fits my plans. It really hurts to spend this much $ in one place...
$600 - I have a choice here of either swapping my DD tires over to Michelin PS2 or getting LT Headers and O/R X-Pipe. As my car currently has garbage tires (not even Pirellis) I think I have to go with the PS2's and save the headers for the future.

I may pick up a $100 CAI if I come across one used, for looks. Let me know what you guys think.

Thanks,

scottmach

Once you install the converter you'll realize it was the best mod to date, regardless the cost.

And I'd consider adjustable shocks/struts.