started with topspeed 2.5'' exhaust but resonator broke so i didnt want to get another resonator welded cause i wanted to try a true dual


So..maybe this nightmare has come to me out of no where heres what i had done from test pipes back..
1. x-pipe
2. 2.5'' piping
3. 2 2.5'' ti-tip mufflers
4. 2 resonators

so my goal was to go to a true dual exhaust ( but heard you lose tq on a true dual rather than a single to dual outlets).

PROBLEM// IF you notice on aftermarket exhaust for 2.5-3'' pipping there are mandrel bends meaning the pipe maintains the same diameter size from the beginning to end. WELL....I didnt notice it until i was under the my car the other day out of curiosity that the bends are ACTUALLY BENT!!!! it goes from 2.5'' in to certain areas then decreases because that are literally BENT and NOT maintaining 2.5'' diameter all the way through SOME PLACES OF THE BENDS HAVE BAD CREASES THAT DECREASE THE SIZE DRASTICALLY . SO that means the air is not going through smoothly as it should be.

DRIVING NOTICES/// from a 2nd gear 4k rpm pull it seems a bit weaker ok maybe i might exaggerate but in comparison to the topspeed its alot weaker. seems that theres a exhaust leak coming the right side..

BATTLES////I've raced many cars and noticed how each individual mod i added had increased my pull harder especially topend. but after putting a new pro-lite flywheel...and i finally broke it in
a 04 g35 with maybe intake NO exhaust... we raced a true race from a dig twice i would launch as normal and stay ahead by a door till 2nd gear and START PULLING AWAY and 3rd gear i start putting lengths on him... and its like he gave up or i seem to just pull away too hard on him..SO I no i didnt slow down.. but can tell the tq is VERY LOW with this dual exhaust... I TRUELY FEEL I WOULDA PULLED AWAY IN 1ST GEAR TO 2ND RATHER THAN 2ND TO 3RD..

SO MY QUESTION FINALY IS SHOULD I TRASH THIS EXHAUST..????

 

I would say yes... creases in the bends? Origami is a great art, but not good for exhaust... might be a good idea to wait for the Motordyne exhaust and not risk poor craftsmanship again.

 

thanks i think i might have to slap a resonator on the other exhaust and put it back on..everyone keep posting...

 

JIC full titanium single exit FTW.

 

ttt

 

very few like the single exhaust look period, plus it doesn't flow as well as dual exhausts.

OP, it is generally not good to go the custom route on exhausts for these cars. You should scrap your exhaust and get the HKS hi power exhaust and call it a day.

 

As usual Your statement is way too general and misinformed. Exhaust is exhaust. It does not know which brand it's flowing though


As far as what size pipes to use:
FLOW = HORSEPOWER
VELOCITY = TORQUE
That may throw you off at first. Let me explain: With more room for the gases to flow, you'll get better horsepower. It flows more freely with an open (wide) exhaust, so it's better for a higher horsepower band. However, you want torque, so you want to shoot for velocity. Torque is produced by the velocity (or speed) of the exhaust gases passing through the system.
If you have the same amount of gases flowing through a 3" system and a 2.5" system, the gases in the 2.5" system will travel at greater velocity, because there's less room for it to expand. Instead of expanding out, like it would in a 3" pipe, it can only expand forward and backward. It's NOT going back into the engine, so it can only expand forward, so that creates velocity. It's a lot easier to design an exhaust system designed for horsepower gains as opposed to torque gains for this reason.

 

THEREFORE???????? I should trash the exhaust

 

you are not going to get good flow or velocity with "creased bends"...

 

exhaust by itself will not change the car's acceleration atleast on first gen G35s not matter what route u go. By switching to a different exhaust it will change how the car "feels" when driving it.
When u race someone before and after there are just too many variables such as shifting technique, shifting RPM, launches. The most accurate way to check before and after results is to race that same particular person from a roll in a certain gear to notice a "difference" if there is any after an exhaust.

The only direct bolt on that will make an impact or ur acceleration without any type of ECU mod is Test pipes, that is all. All the other mods will need some type of ECU mod to compliment the gains.

FYI i have been running a stillen design exhaust with bend pipes like u describe and I have gained over 20 hp peak hp and that much tq with 3 other mods and tune and have a sweet power band. If my exhaust was that bad it I wouldn't gain that much power with it on and shave off 0.5 seconds off of my 1/4 mile time.

 

you have creases and pinch points that cut diameter by as much as .5" at some points???

Edit: I just re-read his post - he didn’t say .5" - but he did say "drastically"... are you saying your exhaust is like this Vlad?? I would think mandrel bend and welds with a smooth radius would be more advantageous... I can’t imagine a pinched bend possible helping exhaust flow or velocity or anything else... My Stillen doesn’t have any bends like that - and I can’t remember seeing any pother reputable exhausts that way... I could be wrong though

 

Well it is not "drastic" but the ID get smaller atleast once on each pipe before entering the muffler. Mine is not mandrel bend exhaust. The pipes were curved by conventional bending methods by pressing the pipes against a curved solid metal to get the appropriate angle on the pipes.

 

no wonder I kick you @ss~ !!!

I've been doing sh!tloads of research on my new tricks Spoke with Shawn, been speaking with JWT, spoke with Doug Crawford, waiting to talk with Howard at TS... be ready friend.

 

Mandrel bends are not what they're cracked up to be and people put too much faith in them. Granted you don't want significant crimping, but a small change in diameter isn't going to impact much on a small displacement motor. Additionally, most pipe bending equipment might crimp the pipe a bit on a bend, but the overall volume of the pipe remains pretty consistent as the shape of the pipe becomes more oval than round.

 

Good point.