Test Pipes

[mikemax99]

I've done a research on the forum but didn't find anything, i know that some parts of the g37 exhaust system fit the ex but can we install the g37 test pipes or cat delete?? I've done this mod in the past with good results for the hp and better gas millage. Want to know if possible on the ex.

Mike

[EibachMBZ]

I don't see why not.
If the G37 HFC fits my car the G37 test pipe will fit too.
I don't recommended though cause w/o the CAT you are not only polluting the environment but you might also poison yourself to death just by idling your car in the garage,
I had CAT delete on my previous car because its' a turbo and it does help ALOT but I am still regret of doing it. When I was circling around parking lot looking for a parking space or stuck in traffic I can smell craps coming from my tail pipe.
I am giving up on power mods for the EX. No matter what you do with the available product now, your car is still going to be slower than a stock EX37. Save the money and just change car later on...

BTW, just to let you know too
There is a dyno testing done for the FX35 just recently
A stock FX35 produce more power than the same FX with cold air system and cat-back exhaust. I found this very interesting and was exactly like what I thought too (This is no news to me because alot of the 350Z were experiencing the same result long ago).

[gr8330]

BTW, just to let you know too
There is a dyno testing done for the FX35 just recently
A stock FX35 produce more power than the same FX with cold air system and cat-back exhaust. I found this very interesting and was exactly like what I thought too (This is no news to me because alot of the 350Z were experiencing the same result long ago).

Do you know what the numbers were?

[mikemax99]

with the test pipes we still have the pre-cat on the system?? I know it's not as good the oe system but not as bad as completely open exhaust. They claim some good hp for the money with these pipes. EibachMBZ What do you think of your high flow cat?? worth the expense??

[EibachMBZ]

BTW, just to let you know too
There is a dyno testing done for the FX35 just recently
A stock FX35 produce more power than the same FX with cold air system and cat-back exhaust. I found this very interesting and was exactly like what I thought too (This is no news to me because alot of the 350Z were experiencing the same result long ago).

Do you know what the numbers were?

Yes.

257 RWHP 225 RWTQ with cat-back and cold air...
259 RWHP 235 RWTQ stock...

[EibachMBZ]

with the test pipes we still have the pre-cat on the system?? I know it's not as good the oe system but not as bad as completely open exhaust. They claim some good hp for the money with these pipes. EibachMBZ What do you think of your high flow cat?? worth the expense??

There is no pre cat system...
The header is very short and it connect directly to the cat on our cars.
I got a good 10whp gain with the HFC, I think you can expect somewhere around 10~13 with the test pipe.
Does it worth it? I really don't know...
HFC are expensive, they are also really hard to install... I can't really feel any performance gain with my butt dyno... (That is one reason I took it to machine to have the actual reading)

[SteveTheTech]

BTW, just to let you know too
There is a dyno testing done for the FX35 just recently
A stock FX35 produce more power than the same FX with cold air system and cat-back exhaust. I found this very interesting and was exactly like what I thought too (This is no news to me because alot of the 350Z were experiencing the same result long ago).

Do you know what the numbers were?

Yes.

257 RWHP 225 RWTQ with cat-back and cold air...
259 RWHP 235 RWTQ stock...

Thats some expensive power loss there.
Now if you are doing it for acceleration and sound factor than that is fine but I am glad people are finally starting to realize these cars hate minor mods.

The guy that works next to me has a 2007 M35S with a Stage 2(?, long tube) and 3/8" intake spacer and has decent "seat of pants" acceleration but no marked improvement in fuel economy over the 40+ mile commute.

I have been a skeptic of aftermarket mods like some intakes,TB bypasses, drop in filters, underdrive pulleys and the such. The quality is usually not as durable as factory, that is especially true for UD pulleys. The only things these cars really like is remapping the ECMs. But no one really wants to hear that a computer (not UpRev) like Impul or Stillen is really what is needed to maximize what you already have. Even with those several thousand dollar addons improvements are still only going to be marginal.

The G guys have been dumping tens of thousands of dollars into coupes since they were new and still not getting impressive results (imo). They sound pretty cool but long term reliability of the vehicle is never as good.

As far as Test Pipes go, I do not know if you all understand what these are but basically they remove the engines primary emissions control material. On anything 2002+ made by Nissan the catalyst serve several engine control functions. They are designed to retain Oxygen to complete the controlled conversion of exhaust gases (mainly CO) to CO2 and purge the waste depending on how the sensors before and after the catalyst say about the oxygen flow rate of the banks exhaust flow. They also provide a small amount of resistance to motion of the exhaust flow increasing back pressure in the exhaust manifold which is actually desired on these engines as it helps warm the catalyst up and functions like a classic egr would. These new engines use valve timing overlap to actually suck in a small amount exhaust gases on the intake stroke to a) cool the intake chamber, and b) provide another opportunity to reduce exhaust emissions.

These really are one of if not the worst modification an Infiniti owner can do to their vehicle.
You will loose torque.
You will loose fuel economy.
You will have check engine light issues (unless you decrease the O2 sampling rate of the downstream sensors, or otherwise alter the O2 sensor signal).

Sorry for the rant, I feel informed owners make smarter drivers. Plus test pipes might (and should) void your engines' warranty as well as make it illegal to operate on US highways. In some states the police can impound your vehicle for defeating required emissions control devices.

I do highly support adding a new muffler or cat back system. They have such a decent purr to them, especially on a cold morning. But do not go into it for the numbers.

Plus dyno runs are erratic and as with any test if you are looking for specifics you need to average several runs. What is the old Mythbusters saying...."Three times makes it science"

[EibachMBZ]

I agree with Steve.

The HFC I have did increase power and no CEL... The O2 sensor is there and everything works great so far. I guess that is one option other than test pipe.
The drop in K&N filter I had did not gain any power on dyno, however it helped the overall power band.
Peak HP is about 200~300 RPM earlier than stock but that is about it...
With both mods I don't see any MPG improvement...

As far as remapping the ECU, I have already talked to Techno Square about it.
They are very popular here when comes to remapping ECUs for Nissan and Infiniti.
The problem is that they do not have anything off the shelve for EX35 to start with so everything have to be custom from ground up... This including removing the ECU from my car or find a used one, send it to Japan for decoding and send it back for more tuning... They did quoted me a good $500~600 for the remapping plus 10~15 other EX35 journey w/o nav (exactly same ECU as my car) to start the project... I can't even find 10 EX35 that have a simple drop-in filter here how am I going to find 10 that are doing ECU remapping?! I gave up

Normally when we are on dyno we do atleast 3 runs. So I guess that is science?

[SteveTheTech]

The HFC I have did increase power and no CEL.

Don't think I'm a wet blanket but I think HFCs are more dangerous to your engine than test pipes.
The reason they tend to cost about $1000 less than OE is not just profit. They are not made to the same standard and quality of original. They alter back pressure enough that harmonic resonance is possible that has caused the catalyst material to break up and during valve overlap become lodged in the engine. If the dealer notices this you will be up a creek if there is ever a failure of the catalyst.
There was a guy in the G forum who actually had to buy a full engine after a failed HFC broke up and destroyed 1/2 of his new 3.5VHR. When it happens it is quick and devastating.

The drop in K&N filter I had did not gain any power on dyno, however it helped the overall power band.
Peak HP is about 200~300 RPM earlier than stock but that is about it...
With both mods I don't see any MPG improvement...

That is because they rely on oil to stop contaminants and increase the filter hole size. That is why they feel so different. Some people swear by them others hate them...in either case they are great for traffic.

Normally when we are on dyno we do atleast 3 runs. So I guess that is science?

Adam and Jamie would be proud.
I see misread dyno sheets all the time here. Although it is worse...much worse on other forums.

[mikemax99]

It seems complicated to have some extra ponys on this nissan. My vq30de and my vq35de has some hidden hp but this vq35hr have nothing to free up easily

[SteveTheTech]

Those were both fairly inefficient engines(comparatively)....Welcome to the 21st century and precision fuel management.

The Stillen Intakes and exhaust sound good but there is really not allot of power to gained there.