EDALVA21

Alright guys here we go. I have a 2000 A4 trans am, with these mods (free ram air mod, mti lid, k&n filter, smooth below, ported mass air, cut-out, flowmaster, and tb bypass.) I ran 12.9 at 107.89 on stock tires.

Now Im installing (Pacesetter lt's, 3in. pacesetter y-pipe, 4in. mufflex exhaust system, dual cut-outs, transgo shift kit, ssf 3500 torque converter and nittos.)
What should I expect with all these mods that Im going to do too the car!!!
Thanks in advance for the input.

RollinSScamaro

iTrader: (25)

hmmm if you hook up good at the track i think you can expect a 12.2-12.4maybe even lower if you are running real good that day! you never know till ya do it! good luck!

Lithium

iTrader: (47)

Yeah, somewhere around 12.2 sounds about right for those mods.

BBQLS1

12.5, but I'm conservative.

BBQLS1

Let us know how you did.

Wnts2Go10O

iTrader: (12)

4 inch for bolt ons.. no more low end for u..lol. 12.4-5 et

LiteEmUp

if u hook then u can also expect to buy a 12 bolt in the near future

Swang

iTrader: (3)

yeah, you dont need 4 inch, unless youre driving a MACK. go 3 inch max.

EDALVA21

Well I went with the 4in. because I know Im going to go with bigger stuff later on and didnt want to buy two exhaust systems, you know??? Im thinking of a 408ci. Pretty soon. Plus didnt want to drop my car or anything like that. Just want it to run!!!!!

Red99TA

iTrader: (11)

The 4" exhaust won't be the restriction on a 408...it'll be that 3" y-pipe...go duals.

86 IROC

iTrader: (14)

See my sig, similar mods, same year car. I have a little bit more left in my set up as soon as I start getting the car to 60' better. The FL heat is here too, I may have to wait until winter to best that ET & MPH.

GT Griller

iTrader: (8)

im gonna give u the benefit of the dought and say 12.0-12.2 just cause if u hook and with that 3500 stall u wont need much low end and ur headers will move u top end very well.

EDALVA21

So do you'll think Im going to have problems with that 4in. exhaust?

LS69TA

iTrader: (30)

Slow98Z is running low 11.90's consistently with pretty much the same boltons.

Swang

iTrader: (3)

Quote:
Originally Posted by tim99ws6
well. His theory is to increase backpressure, and in effect bring the torqu into a more useable range. 2.5 is probably plenty big enough to flow for bolt-on cars. They trick is the bigger the piping, the less the backpressure, the slower a car "feels".....it actually will increase Hp by freeing up backpressure, but with a larger piping, you'll lose some bottom end tq. That's why some guys think that when they open their cutout, their car "feels" slower, but in actuality, you're just sacrificing bottom end torque for top end hp.


The guys theory in effect has some merit, but i seriously doubt he'd be "doing you a favor" by dumping a 3" exhaust for a 2.5 exhaust!
I think youve got the jest of it, but backpressure is not what helps you out, its exhaust velocity. Kind of like over porting a head can kill velocity and hurt power, too big an exhaust can theoretically do the same. Its the reason stepped headers and merge collectors exist. Bigger isnt always better when youre trying to eek out every last possible ounce of power. The slightly smaller 2.5" pipe will boost velocity without creating too much backpressure. The added velocity will create a stronger scavenging effect as the pulses go through the X pipe and down each leg of the exhaust. In order to run at optimum, you shoudl run the smallest pipe without building backpressure. That will keep velocity up and will increase torque everywhere, not just down low.

What does all this mean in the real world? Probably nothing. Any change between 2.5" to 3" pipe would be well within the dyno's margin of error, as well as within any drivers variance. The guy isnt necessarily trying to screw you over, but he is a little irrational about how much it will help you (not likely any at all)



thats is quoted from another thread going on. read the part about velocity. take what you may from that. but 4 inch just seems...how do i put...excessive

EDALVA21

I mean will the 4in. drop my performance or will it be the same of a 3.5? What do you'll think? Thats about the only thing thats wrong with what im going with remember I will also have my dual cut-outs. I was planning on putting that exhaust in for sound and performance, you know.

EDALVA21

Another thing the tubes are 3in. the muffler is 4in. sorry if I got people confused. So do some of you'll still think that its to big????

777

iTrader: (21)

if that's the case what should i run with my mods and numbers in sig...keep in mind that i have 315 street radials...however, once they are warmed up they are pretty sticky...

kkkevvvinnn

ya your prob going to need to get a 12 bolt rear end to replace our stock 10 bolts. If you have sticky tires that 10 bolt might not hold up. I would say you will be at around 12.3-12.5

jay_99z

iTrader: (5)

With 3500 stall....... low end = won't be seen.



I'd say 12.3- 12.4