Are any of you guys running the single 4 inch exhaust by Mufflex? If so did you order your Y pipe from them? I just recently had the Mufflex 4 inch single exhaust installed but I didn't order the Y pipe to go with it, so the installer had to make the factory Y pipe work which is kinda defeating the purpose because now I have a factory Y pipe that goes down to 2.5 or 3 inches going into a huge 4 inch pipe. That has to be restricting my exhaust flow. Is there any companies out there that makes a Y pipe that goes into 4 inch single pipe?

 

to me what allways restricted the 4th gen exhaust was the 2 into one into 2 ,i run a 2.5 true dual now with headers ,takeing out the cat an the huge mufflers was enough for me ,before that i had magna flow 20 x 4 inch tips wich gave it a louder sound ,i dont know of anyone useing more then 3 inch on the 4th gens unless your talking about modification,,but there also depending on years needed for emissions ,my 95 is excempt an now breaths the way it should ,but with whole different set up i needed it ,an it all varys from state to state ,i would say no there is not unless you want to mod one an i am sure guys do i could be wrong some track cars probley have 4 inch ,for your z28 true duals an a tune should make huge difference getting rid of the stock stuff ,being a 93 it should fall excempt ,so 3inch straight pipes should feel about 30 hp with a single chamber muffler or full bore ,but i also need to adjust my exhaust as the guy that did it put it to low ,they call them exhaust artist,my friend has a plan for me ,that will work on this year

 

what model/engine? 3.8 will not get any gains going that big, may have power loss in areas of the power band.

 

4 inch exhaust, so you are somewhere around 1200 hp?

 

its a z28 93 from other posts is why i said 3 inch i think ,or just run true duals with 2.5 inch an a tune should be fine, seems to me going from 2.5 to to like 4 inch tip is ok ,but realy no need for the 4 inch pipe,some guys just clear out the cat if the car falls exempt ,can make a huge difference with a better breathing muffler set up

 

I use the 4" mufflex on mine but the crossover pipe was from Edelbrock along with my headers. The Edelbrock crossover doesn't fit as well as the Hedman header crossover and hits ground objects a lot. Mufflex 4" looks great and sounds bad but it earns it's expense once over 400hp. For use with stock manifolds I think the 3" systems are good enough and I like the Summit brand 3" one into two system - over a lot more expensive one into two systems.

Just FYI, John Lingenfelter (RIP) had a 383" LT1 build that made over 450hp with the stock exhaust manifolds. Buy his book if you can, good solid info.

Hope this helps. Good luck.

 

4" is big,3" will fit nicer and be just as good if not better, like said if you aren't pushing 1200 hp

 

2.5 works fine for me at 450+,a 4 inch tip looks cool ,i have ground clreance issues enough with my 2,5 ,though installers fault on that ,going to fix that i may go up to a 3 inch pipe ,but 4 would couse clearance issues like said the 2 into one into 2 never made sence to me an that mine was starving for air after the engine swap so my only choise was true duals an headers ,i know it was all about emissions but for 95 on back they fall excempt most places now ,an some states one can run open headers practically

 

You all would be surprised how well the Mufflex 4" system fits. I had a least one exh shop tell me it wouldn't fit but I found a shop with experience installing Mufflex 4" and it was no problem and looked great. The big issue you will find is a header Y pipe to fit up. My Edelbrock Y hangs to low and scrapes with my lowered car. Hedmen makes a good fitting Y for thier headers but had to come off because not smog legal in California.