I'm just wondering what are some of the faster cars with a single four inch.

I am just intersted in what a car with 1 3/4 hooker super comps a mufflex three inch y and single foru inch is capable of?

I have heard of cars in the low nines with this exhuast, is this really possible?

 

Being one of those in the low 12 second club, and soon to be part of the (hopefully) low 10 club, I can say without a shadow of a doubt, that a single 4 inch system will not sustain a car into the nines. Compounding this problem is the use of nitrous. A 4" exhaust (single) will be very restrictive for a 383 running 200 horses of nitrous. Mufflex is an EXCELLENT quality street/strip exhaust though. I own a setup.

 

i know of a guy that runs high 9s low 10s with an 85 IROC that has a turbocharged 305 in it, he has a 3" random tech catback

 

That is not low 9's, and that is also a car that builds power off of backpressure. Most of the budget guys that are in this category cannot run a single 4" due to the restriction as most of them run nitrous. I mean, lets be honest, you can make a street legal VW run 8's with a 2.5 inch exhaust, but it is going to take hella more money than a Chevy. Just thinking about the average racer here.

 

There is a guy here in our local club that runs high 7's/low 8's (soon to be the fatest LS1 on the earth) on his 382 Turbo LS1 through a 4" ypipe and cutout.

 

Here's something to think about....

George Baxter ran well into the low 9s, maybe even high 8s with a 4" Mufflex.

If you don't know his car...it's a convertible 4th gen Camaro with a Vortech-blown 383 Gen I small block that puts out well over 900 hp.

I read he switched to a true dual Borla muffler setup and ran a few tenths quicker but trapped the same mph. He believes the heavy weight of the 4" system was costing him some ET, but not horsepower.

Unless someone is putting out serious hp like Mr. Baxter, then a 3" system is more than adequate into the 10s.

 

I have personal experience...I switched from a 1 3/4 SLP shorty with a mufflex 4" setup to a 1 7/8 setup with true dual 4" exhaust and dropped from 12.3 to 12.1. I have not yet finished the fuel system on my new motor, so I can't tell you what kind of times it will post, but for nitrous, bigger is always better. You can get away with a 1.94 intake valve well into the 9's as long as you have a 1.7 exhaust. Cylinder pump is the enemy of nitrous. Getting that exhaust out is key. I am not a turbo/blower guy so I cannot speak to you about that, but if you are running nitrous, generally more flow = lower et.

 

the best turbo exhaust is no exhaust! they only work off pressure in the manifold. most turbos have at least a 2 to 1 ratio in the exhaust maniflod vs boost. did you say you have a dual 4in on a car that runs 12s?

 

12's on the old 355 motor. The new motor should run low 10's sprayed if I can hook up. It is an ovalized 4", meaning i put it in a press and ovalized it. It isnt really an exhaust, so much as a muffler off the header and small length with a turndown. Doesn't even exit the car.

 

 

I cant find my Mufflex pictures!! This is a pic from last year but you can see the low point of the mufflex system with a 4" y pipe.

 

I will be running a true dual 3" xpipe oval tubing with borla zr-1 mufflers.. my motor with juice is good for high 9s and also a daily driver in the summer

 

the benefeit of true duals is that you can flow a lot of air AND have the velocity stay high

 

I'm just a newbie, but I'm fairly sure that a single 4 inch system will have more velocity than even a dual 2 1/4 system. If you run duals w/o a crossover, only half the motor's exhaust is going through each pipe. A properly y'd 4 inch system will have greater velocity, based on more volume trying to be moved through an ever so slightly smaller orifice. Think of it like headers: Tri-y's have smaller primaries leading into larger secondary pipes, increasing velocity and torque throughout the low and mid-range. Large tube 4-1 headers have less velocity, therefore hurting bottom end, because of a simple lack of velocity.

 

i would have to say yes you can get into the nines with a 4 inch exhaust.

you can see my simple site at:
http://darcom.org

 

buddy of mine was running hooker and mufflex and was trapping around 142 in his 82 sport coupe, last i knew though he switched to true duals, havent talked to him for a while

 

dual 2" flows more than a single for im pretty sure it has to do with surface area i read it in a post a while back. bigger is not always better

 

Pi x r^2. 2" diameter has 1 inch radius. Truncating pi to 3.14 you get: 3.14x1x1= 3.14. Times 2 for two 2 inch pipes is roughly 6.28.

4 inch single= 2x2=4x3.14= roughly 12.56 sq.in. flow area, as opposed to 6.28 for dual 2 inch.

3 inch duals= 1.5x1.5=2.25x3.14= 14.173

3.5 inch duals= 1.75 x 1.75= 2.8425x3.14= 8.92445x2= 17.8489

It's simple mathematics. And considering all exhaust tubing has .040 inch wall thickness, actually try the equations with these numbers:

1.92 in for 2 in
3.92 in for 4 in
2.92 in for 3 in
3.42 in for 3.5 in

:lala:

 

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