03 vs 03

[Tim Lester]

Hi I have a question for everyone I ran an 03 cobra last week end from 70 mph to about 110 mph and I pulled him about a car and a half, My car is all stock except for a K&N, I did'nt talk to the guy that I raced but he had a catback exhaust system not sure what else if anything. I know when you free up the exhaust you lose some boost, Now is it possible that he did'nt gain any power with the exhaust, or what he lost in boost he gained it back with the exhaust, an even trade off. Just makes me wounder???

Also is anybody running pulleys with the stock exhaust system?

Thanks tim

 

[03CobraBro]

Thats something I'v been wanting to know too. Anyone out there running pullies without an aftermarket system?

Personally I dont mind the stock exhaust. I like my cars alittle bit quieter, in the 03 Cobras case I want to make sure I can still here the blower over the exhuast.

Anyway Ill be getting a 2.90" non slip pulley and a Diablo sport chip, hopefully by christmas time (and ill be running stock exhaust). If this winter isnt too harsh and the state doesnt go over kill with salt this year, providing you havent already upgraded, ill let you know how it works out.

 

[loose nut]

Originally posted by Tim Lester
Also is anybody running pulleys with the stock exhaust system?

That's a great question! Seems like most everyone installs the pulley as a later mod than the exhaust...but surely someone has some info. This could be interesting.......... :shrug:

 

[hj16]

Originally posted by Tim Lester
Also is anybody running pulleys with the stock exhaust system?

Thanks tim

Tim, I'm running a 2.90 with the stock exhaust. In a word, it sucks. Yes, I'm making more boost but thats not exactly wanted. When I switch over to an aftermarket exhaust next spring I'll lose about 2psi but will pick up anywhere from 30-40rwhp.

Boost (psi) is a measurment of restriction. Our engines are just air pumps, making alot of boost isnt very effective at moving air. When you open up the intake side (CAI, TB, Pulley), you should also open up the exhaust to keep it efficient. Yes, it does need backpressure, and thats why a 2.5" aftermarket exhaust is used on most modded cars (380-600+rwhp)

Now, to your race-
Chances are that you can shift better, or your car was stronger from the factory. Hell, some stock 03s only Dyno'd 350rwhp, while others Dyno'd 380rwhp stock.

 

[03CobraBro]

How large are the stock pipes? I was under the impression they were already 2.5.

My dads running 2.5's on his 5.0 and they measure out just about exactly the same as the stock tubes on my Cobra.

 

[hj16]

Originally posted by 03CobraBro
How large are the stock pipes? I was under the impression they were already 2.5

Stock pipes are 2.25" but in some areas they are crimped down to 1.9". The 4 restrictive cats take away alot too.

 

[03CobraBro]

Originally posted by hj16
Stock pipes are 2.25" but in some areas they are crimped down to 1.9". The 4 restrictive cats take away alot too.

Iv been thinking about removing the cats... Would there be any noticable difference?

 

[DD2000GT]

More boost does not necessarily mean more power.

When I had just my Densecharger, my boost gauge hit a little past 10. After I put my catback and X-pipe on, my boost dropped to 8 1/2 or so, but the dyno showed much more power with the addition of my exhaust system.

My guess would be that at 70 MPH you dropped it into 3rd gear and he had it in 4th gear.

 

[NJCOBRA10thA]

Regarding hearing the supercharger over the exhaust. I have a Borla stinger and stock pullies for now and i have no problem hearing the supercharger when I hit it.

 

[mmars]

Originally posted by 03CobraBro
How large are the stock pipes? I was under the impression they were already 2.5.

My dads running 2.5's on his 5.0 and they measure out just about exactly the same as the stock tubes on my Cobra.

The mufflers also have something to do with it. The stock pipes are 2.5", but the mufflers are very restrictive.

I put the 2001 Cobra exhaust on my 03. Less restrictive, nice tone. Best $100 I spent.

--Matt

 

[b34TgNu2]

How do u know the 2001 cat back exhaust is less restrictive than the 2003 .... Just Wondering

 

[mmars]

A very good friend of mine at SVT. The 2001 cat-back was originally going to be used. However, the noise levels were too high and they had to create a more restrictive cat-back.

--Matt

 

[coleman]

when i had my 2.80 & chip installed, i had the stock exhaust.
i only made 409/455 with that combination.
with 3" manifold-back exhaust, my #s climbed to 442/480.
stock exhaust was holding me back!

 

[unit213]

Stock exhaust here...

Video

 

[Orange Poison]

Is the 2001 catback still a 2 & 1/4 inch?

 

[RickSvt]

When I put on my 3.2 pulley, steeda cai, magnaflow catback, I am seeing on the stock gauge about 11-12, its past the 10 mark. I didnt lose any boost when I did the catback.

After I installed the exhaust, no intake and pulley, I was doing about 9.....no loss in boost

Rick

 

[hj16]

Originally posted by mmars
The stock pipes are 2.5

They are 2.25", but you are right about the 2001 CatBack being less restrictive.

 

[wjfawb0]

I am getting a 2.95" no slip installed along with the metco aux. idler tomorrow. I'll be getting dyno tuned as well. My car only has the K&N aircharger kit right now. I'll post numbers tomorrow night.
My understanding is the stock 03 exhaust is 2.25" just like the GT exhaust diameter. I may go for a Dr. Gas offroad X in the near future.

Remember too. CFM (cubic feet per minute) is the real ruler of power capability. Porting and polishing heads and intakes can actually drop boost because it flows more CFM. You'll make more power and less intake pressure cause it flows better.

-Jason

 

[Ghoust]

the other thing you have to consider here is the fact that no 2 cars are created equal. Especially supercharged vehicles. You just might have a factory freak on your hands!

 

[Friendchicken]

it was probably your shift points were better than his. But, yes- there are factory freaks... chances of you having one is rare tho.