Can anyone tell me if a 3.5" test pipe will make a big difference in sound and performance if you attach it to the 2.5" exhaust. I currently have APS TT with the APS 2.5" test pipes and exhaust.
Also, when is advisable to run Water Meth Injection. Will you see any power gains if installed.

Cheers

 

you'll have to check with zivman and mrtomcat, they both have the 3.5 TP attached with the 2.5 exhaust. I'm certain that mrtomcat got his car to 600whp with that setup and water injection.

you'll def see power gains with w/m when you advance timing properly. most ppl add it just for added safety. if I were you I'd take the car to a shop that has installed many W/M kits and know what they are doing.

 

My assumption is stock motor:

the 3.5" won't make a big difference at the power levels you will be seeing. Unless you go with a build, you won't really "need" the bigger pipes. that said, I think they are nice and worth the money.

I am not a big fan of W/M injection. I like to keep things simple - well as simple as they can be. Adding W/M injection may add some safety to your setup, but not really anything more than a proper tune would.

On a stock block, you can make more power than the block can handle without the 3.5" pipes or W/M so I just say, save all those upgrades until you come to the point you build your motor and shoot for 500+

 

Hi Zivman, my engine is far from stock.. I PM you earlier. But just for everyones info, here is my setup:
https://my350z.com/forum/showthread....light=veilside

I currently still have the Unichip and standard Fuel System, which will change to the Haltech EMS and APS Extreme very soon. Will be taking this week for first Dyno run after Rebuild. I am hoping to get 450whp. What PSI will give me that HP? Once I receive my new stuff I am hoping to do 600whp. Do you think this is achievable? and will the 3.5" test pipes benefit me with current build and is there a difference in exhaust sound. What is your current spec on your car?

Regards
Noer

 

With your compression ratio, I would think about 12-13 psi should net you 450 whp on a conservative dyno.. considering I don't see cams listed. with the 2.5" exhaust, 600 is going to be hard to come by. I think it is doable on a GTM type dynojet, but not a forged performance dynodynamics. Even with a dynojet reading, you are going to have to push 18+ psi on a racegas map. At that point, the bigger pipes and W/M injection will definitely be beneficial. I think you will be limited by your stock cams and the 2.5" exhaust.

The 3.5" pipes won't affect exhaust note much at all.

My current setup is as follows
GTM spec ED arias pistons .020 over 9:1 CR
Eagle rods
GTM stage 1 FI cams
GTM spec ARP 2000 head studs
HKS head gaskets
JWT valve springs/shims
Forge actuators - red springs
HKS Fcon Vpro with knock amp
HKS EVC 5 EBC
APS TT conversion
APS extreme fuel system
ATS twin disc carbon clutch
APS 3.5" dumps
APS 2.5" exhaust

Thing is, my motor is just getting back to me today and is not yet up and running. My previous build was similar to that listed above except 8.8:1 CR on stand arias pistons, stock cams, and oem HG and standard ARP head studs.

Car made high 400's low 500's at 14 psi (depending on dyno). With my current setup, I am looking for a lower boost tune at about 1 bar (14 psi) at around 500 whp and maybe shoot for the moon at 18+ psi to see what I can pull for the hell of it. First things first though, need the motor back in the car and get things up and running and broke in

 

My tuner told me if your going 3" one place, you got to have it in another.

Aren't the outlets on the turbo manifold from greddy only 2.5 anyway?
I wouldn't see an advantage in going over 3" all the way back.

 

With the big test pipes and 3" exhaust, it will definitely make the higher HP goals more realistic, but you need to ask yourself if the noise factor is worth it or not. Me, I am fine giving up the HP for an enjoyable ride

 

Bro you do NOT need to get the APS extream kit for your goals IMO. Meth and pump gas will get you there easy or a race gas tune @18-20 psi. Look at the dyno graph of an extreme kit. It takes forever for that thing to spool. IMO you'll have more fun with your APS TT, and will feel faster. Save your money. I yet to see anyone with a APS extreme kit put down some track #'s.

As far as the 3.5 pipes I had them on my old set up and it did sound a bit louder than my 2.5. I hav ethem onmy current set up and love them.

Also dont get all round up on dyno numbers, thats all they are numbers.

 

I think by "APS extreme" he was only referring to the fuel system

 

Oh my bad

 

I just recently switched out my APS 2.5 test pipes and Injen SES exhaust for the APS 3.5 test pipes and the Greddy Evo TT exhaust..Went from 385rwhp to 425 rwhp on 93 octane on the same DynoJet ..I have the 5AT and a stock block.I believe JT from PF had me at 10psi w/ A/F at 11-11.2

 

You gained 40whp@10psi just by changing to the 3.5" dp's and Evo TT exhaust? That's not believable. Did you get tuned as well?

 

Yes that was with a tune from JT at PF and was a mid to agressive tune. There are dyno sheets somewhere in these forums to back it up, its just not worth my time to find them. B.S. is not a part of my vocabulary, so believe it.

 

Learn how to explain yourself better next time. You made it sound like you gained all that power just from the exhaust enhancements which is total B.S. The reality is you gained most of that power from the tune.

 

Why would you ask a foolish question like "was that with a tune". Of course it was, I could care less what the #'s are on the dyno, to me a dyno is for tuning. I'm not really concerned about the #'s.I hope your not saying that having bigger test pipes won't yield more flow/power. To be honest I really don't know what your saying...
If you don't know what your talking about, which is the case here, you should go back to the N/A forums.I don't know why I would have to explain myself better, guys with knowledge about cars I'm sure understood. Where do you guys come from with all your stupid knowledge...

OK now its your turn to bash me, but you will not get another comment back from me because it would be a waste of time.

 

does anyone know if the larger test pipes make the spool a little faster compared with the 2.5?

 

Yes that was the first thing I noticed....

 

coachk, by about what RPM or how many RPM's faster did it spool up?