JonnyW

Hey everyone, I own a 2013 Mustang GT Premium with the track pack. After I installed a Steeda CAI and Bama V1 93 Race tune a year and a half ago, I would easily run 4.4-4.5 0-60 without breaking a sweat. This was determined with Track Apps.

After installation of more mods, my times are much slower. I'm now running 4.8-4.9 0-60 times and am trying to figure out why my times are so terrible.

After running 4.4s with the CAI and tune, I installed
Boss 302 manifold
Kooks catback exhaust
BAMA V2 93 race tune
MGW short shifter
Powerstop drilled/slotted rotors (I'll get to these in a minute)
JHR motor mounts
Whiteline trans bushing insert
Steeda SS clutch line
Velgen VMB5 20" wheels
Nitto NT05 275/35/20 front, 305/30/20 rear

Amsoil 10w-30
Amsoil ATF

Looking at this list, intuition first tells me that my problems are with the manifold and the wheels. I would agree, however, my wheels setup plus sized meaning the overall diameter is actually a touch smaller than the track pack setup. 28.04" vs 27.76" and the wheels also weigh much less than the stockers. Front-rear, 31-33lbs vs 27-29lbs or something similar to that. The rotors I added also weigh less than Brembo's rotors. The rotational mass shouldn't be enough for me to go from 4.3 to 4.8 in 0-60 times. The only problem I can think of with the wheels, from 19 to 20 inches, that the weight is spaced out by a half inch in radius all the way around. The tire's diameter stays the same with the shorter sidewall.

As for the Boss 302 manifold, I know I lose a little power down low. But once I shift at 7400 RPM, I'm right back in the power band in second gear at 5500 RPM. Doesn't that make up for the difference in terms of times?

All other conditions are about the same, but I've tested multiple times on different days and consistently ran 4.4 before I added these other mods. I'm doing the same now and can only manage 4.8. Can anyone tell me why my times are this slow? I'd like to think that they should be the same as before.

I'm debating on unbolting the Boss 302 manifold and installing the stock coyote manifold to determine if my slower times are a result of my manifold, or my wheels and tires.

I plan on ordering longtubes in the future. Would this make up for lost power and then some considering the Boss 302 manifold? Much thanks everyone.

WJBertrand

I wonder if the larger wheels are carrying weight further out from the axle? Even if lighter overall might there be a negative effect carrying the weight on a larger radius from the axle? I agree the manifold would be my first suspicion. Seems like a good choice for high RPM road course running but not so much for drag racing or street driving.

JonnyW

That was my concern as well, but I still don't think that would have changed my times so drastically. The Boss manifold has been a mod that will look good under the hood and on the dyno, but I'm starting to wonder if it makes these cars slower.

I did read a thread earlier today about someone supposedly running his GT with the stock manifold at the strip, then installing the Boss manifold and running .2 seconds faster in the quarter that same night. However, proof has also been in the pudding that it does hurt your 60' and 1/8th, so I'm guessing it hurts your 0-60 to a degree.

Looks like I'll be installing the stock manifold to see if the problem lies within the boss manifold. Upon this, I'll also know how much, if any, my wheel setup impacts the performance of my acceleration. I'll relay back in a few days with this information. I'll need to order tunes from BAMA to be able to accommodate the stock manifold.

scottmach

You should be shifting at 7600 minimum for the Boss Intake to be effective.

Have you logged the tune for Bama so they can see the logs? Are you sure they're turning off clutch protection?

JonnyW

I would be shifting at 7600 RPM if I wasn't getting locked out. I did call Bama yesterday and they sent me info to data log. I'll be doing this later today.
What is clutch protection? I have the MT82 manual trans, very common problem with us guys is that we get locked out extremely easily. I have DOT 4 coming today and will be doing a brake fluid swap to see if that helps clutch disengagement at all. I'm curious to know how this "clutch protection" you speak of works. Also, I believe the highest limiter Bama puts on the car is 7400, I'll verify tomorrow.

scottmach

Bama was not able to turn off torque management/clutch protection in the past so I don't know if they can do it now. Very important.

Yea one of the biggest reasons the manuals struggle with the Boss Intake is because of the transmission/clutch itself not allowing high rpm shifts.

Slowbra302

Not to thread jack, but Scott, can you elaborate on the clutch protection/torque management please? Thanks!

JonnyW

Not thread jacking as I'm very curious as well. From what I've heard, the stock clutch is one of, if not the main issue with high RPM shifting. Something to do with the pressure plate/pressure plate bolts backing out?

Aside from this, I just stumbled across something very interesting. Check out the dyno numbers of coyote bolt-on mods. The boss 302 manifold robs some serious power compared to the stock manifold. Even with headers.

http://www.mustangandfords.com/how-t...s/viewall.html

So basically you'd see consistently higher numbers overall with the stock manifold. Unless of course you're getting into cams and heads to get your RPMs up to around 8000. Looks like I'm going back to the stock manifold.

AMAlexLazarus

Hey Jon - Definitely interesting. Can you shoot me a PM with your Email address? I'd like to get a look at the logs with the Bama Team. I know they're running a little behind but I'll make sure that it's fasttracked for you.

Alex

Dino Dino Bambino

There's your problem. The Boss manifold requires a custom tune and if you're using a canned tune, it may not be dialed in correctly.