So i went to the local exhaust builder with a resonator, dynomax VT muffler and a 3" SP cutout.

I told him I wanted a X pipe from my downpipes. 1 side goes to res/muffler, the other 3" side to the cutout.

Well he merged the 3" downpipes into a 3" Y, then resonator to a long run of 3" back to another Y under the trunk that split into the muffler and the SP cutout.

The car is super quiet, like you can barely hear its running. But my real concern is the effectiveness of the cutout in the rear of the car, after all that single 3" piping and resonator.

I wanted the X so that the cutout was as close to the turbos as possible. It wasnt an inexpensive setup either, which really has me feeling buyers remorse right now.

I was just so wrapped up with how quiet it was (coming from turndowns and having to wear ear plugs everywhere), that it didnt really dawn on my the cutout location.

I think I will drive back there tomorrow to discuss it with him. Already out a lot of money, but its really not what I originally discussed. I just feel like I'm SOL since I already paid.

 

do you have pics? I would like to see the set up if you dont mind

 

This thread needs some photos.

 

pics! and a soundclip!

 

so you were pushing your "bigger" turbos through just a single...3"....not even a true 3' dual... man....(i haz 4")
get that cutout as feasible close to the turbos i guess...should be a worthy mod (sp cutout)...stop complaining of the cost int he sense that it wasn't done appropriately in the first place

 

davidv - THANK YOU... that made me

Rich... have you done the math, doesw it restrict flow? Maybe Terry would know for sure.

 

So if I understand you correctly Rich... you essentially have a single 3" exhaust prior to the SP exhaust cutout at the rear of the car? For comparison, I don't recall seeing anyone with a Z or G run more than 500-550whp with a 3" single AAM or JIC exhaust and open wastegate dumps.

I think it would be more ideal to have two SP 3" exhaust cutouts with them installed prior to the Y, and then run a single 3" the rest of the way back with your resonator and muffler. That would give you the best of both worlds IMO... a quiet & mellow exhaust for low boost street driving, as well as a completely symmetrical and unrestricted exhaust for your high boost settings.

 

Pics or ban

Based on my mental image I don't see the cutout as being of much use on a good hi-flow muffler given that all the cutout does is bypass the muffler in the rear meanwhile single 3" piping all the way back??

 

jtgli is running a single and 700+whp, not sure if its 3" or 4" though. Open dumps too.

 

no pics

ya pretty much. if he woulda made the X pipe, instead of the Y, it woulda been a full 3" dump right after the turbo and then the normal exhaust on the other side. I figure that would flow enough bc they are straight thru mufflers and less restrictive than a gretty TiC or GTM true dual...

i;m goin back tomorrow bc he put the cutout tip out the back and I told him i didnt want that anyhow. I use that side to jack up the rear of the car at the track.

 

According to his 700whp thread, he has a custom 4" single exhaust.

https://my350z.com/forum/forced-indu...whp-thead.html


There's a big difference in flow between a 3" and 4". Supras run 1000+whp with a 4" single exhaust. Not saying that Rich couldn't make more than 550whp with a single 3". I just haven't seen anyone push a 3" single on a VQ beyond ~550whp IIRC.

 

Hmmm... I'm doing almost the opposite with my G... 3.5" downpipe Y'ed to dual 3" all the way back with resonators and mufflers. I personally don't like the single muffler look on the G compared to the Z. It should flow plenty without the need for an SP exhaust cutout valve and I don't think the sound will be obnoxious for me.

If I were to run a single exhaust with a high power TT setup such as yours... I'd run two 3" exhaust cutouts (one off of each downpipe) before the Y... or I'd Y the 3" downpipes into a single 4" all the way back and use one 4" cutout inline before the resonator and muffler.

 

ya i wanted to keep it simple. there's really no room under the car for 2 cutouts with the oil return pump and the turbos. thats why i think he just did a Y because it woulda took a lot more time on the mandrel bender to get it right. I like the single because I can use the open side to put my jack in under the pumpkin to lift the rear end in 1 spot. makes swapping to DR/slicks much faster at the track.

my breakin tune made 620DD at 14psi (wastegate springs, no BC) with my turndowns, so the cutout has to be relocated.

at this point, the money was spent, so the best I can do it b!thc that he didnt do the X pipe like I wanted. we'll see how it goes tomorrow. every turn, i feel i get raped on what I want vs what I receive. So bored of this car!

 

Rich if you paid for something you did not gt, then I would go back and tell him. That is not right on closer inspection. He took the easy way out, not the way you were quoted.

 

well I took it back, he said no problem dont stress....

gotta call dynomax after I get the car back. I think that flapper valve is making a racket. good thing for their 90 day sound guarantee. Its too quiet really. Although the exhaust guy alluded that the car "could make a lot of money" being such a sleeper. HAHA

i'l post pics of the final outcome when its done. basically just a dual 3" exhaust, 1 side mufflers and the other is straight pipe.

 

ya, there would be more restriction having it on the rear.

based on resistance in physics area x length (a little more complex) would be the defining thing in something like that. So as you increase the length of the pipe you will increase the resistance to flow.

Now, how much, i have no idea. I would want it the way you want it: downpipes to an x pipe with 1 going to a muffler and the other to the cutout. That way there is almost zero resistance on the turbos when they spool.