Originally Posted by SoundPerformance

What size are the stock DPs on the APS kit?? I can't see needing anything larger than a 3" on a twin kit. A pair of 3" DPs would be good for 700 RWHP per turbo.... or 1400 RWHP total.

Originally Posted by Glex25

I tried searching the forum but can't seem to find many people running the 3.5" downpipe apart from maximumsportz.

I have a few questions plus I would like to hear from people that actually have it and used it.

1) How do you like it? Droning?

Basically sound no different than the 2.5" down pipes. the catback is going to determine if the car drones


2) What exhaust you have connected with the downpipe? APS 2.5" ->The 3" is INSANELY loud.

3) Did you change over from a HFC setup or TP setup? I swapped out from the 2.5" APS pipes

4) How did it affect your AFR?
Don't know exactly because I did it at the same time as other parts and had the car retuned. If the catback is kept the same, it isn't going to be a dramatic difference

5) Difference in turbo spool?
Doubt you would be able to tell, but with the retune, my power seemed to come on slightly faster.

6) What kind of gains did you see from this upgrade?
This will really depend on what your build consists of... if this is a stock motor, the pipes are not limiting the power so there really is no gains. If you are pushing the limits of a full build, it may help a bit, or at the least take some thermal load off the motor


7) Does a adapter exist to add a Tial BOV to the APS TT system?
[B]If one doesn't, I am sure you could have a shop weld in the appropriate plate/bungB]

I know I will probably need a tune.
If all you are adding is the larger test pipes, a retune would be advisable, but doubt it would be 100% necessary

I do have a map that adds a little extra fuel for track events.
If I do have to get it retuned I have a set of DW600cc injectors I might as well throw in.
Would I have to revert the injector harness back to stock over the one that the APS kit comes with?

Originally Posted by Glex25

While we are at it.
CJM Stage2 Fuel return system would have I have to change anything in the Gas tank sender unit over the APS modification?

http://www.airpowersystems.com/350z/...uel%20Pump.pdf

Originally Posted by Glex25

Ziv I have a motor I'm tearing down for a build.
I'm still on stock block @ this time.

For some reason my tuner believes my HFC might be creating
backpressure to the point that it might be stressing the wastegate solenoid.

Why do you say "for some reason"? This is exactly what I would expect from a restrictive exhaust (which is what any exhaust system that has a catalytic converter is)

When I first got the APS system installed I use to see smoke coming out of my exhaust
on deceleration and since then I have used HFC. I have done the shortening of the
oil return tube per APS instructions and hopefully that issue will not rear its ugly head
with the new pipes.

Would think it was nothing more than improper oil level or the returns

For now I'm just looking to add the pipes but if i need a retune I would like to
add the additional fuel elements so when its time to replace the block it will be
less things I will need to troubleshoot in case something goes wrong.

Originally Posted by Glex25

Ziv u a meanie

Yeah I know the HFC are holding me back.
As I said I'm just afraid of the oil smoke on deceleration coming back
(The return line has been modified per APS instructions and oil level is always on point no higher than the L line on the dipstick)

Not really sure how test pipes would have anything to do with the oil situation I am just a simple farmer though

and If it was test pipes that was needed then the APS 3.5" is the way I would go.

They should be at my house by tomorrow
I'm more afraid of how far my AFR would be going from HFC
to TP.