Ebay Y pipe reviewed and dyno'd
 

Got my $99 ebay Y pipe installed and dyno'd today.

I tried taking some pics on my phone, but they didn't show up later when I tried to load them on my computer, not sure what happened with that. Anyways, the pipe is one of these:
http://i.imgur.com/P8AQ8.jpg

Ebay Y Pipe Weight 10.41 Lbs
Stock Y pipe Weight 14.51 Lbs

Dyno runs were done same day, a couple hours apart, 3 before runs and 3 after runs are shown. The car had a tune on it before the Y pipe was installed, and the tune was re-tweaked a bit after install. So runs are comparing tuned vs tuned.

Only other mod currently is PPE Longtube headers. Exhaust after Y pipe is still stock.

http://i.imgur.com/Kv1Iz.png
How it sounds:
With just PPE headers and stock exhaust, there was an annoying rasp starting at 2300 RPM, even at very light throttle. This was annoying to me because it made my car sound obnoxious even when I was trying to drive conservatively, just putting around between stop lights, etc.

With the new pipe, it seems the rasp doesn't start until 3000RPM, and only when giving more than maybe 20% throttle. So if I'm cruising and accelerating lightly, I don't get the rasp like before, it's more controllable. At WOT it is a bit louder than with the stock Y pipe, but not a whole lot.

Overall I am pleased with this purchase. Can't go wrong for $99 shipped.

thank you! awesome gains for $100.

Whats with all the weird drop offs in TQ at around 3-3.5k rpms? :ugh2:


What's the ID of the new Y-Pipe?

The PPE headers do rasp a lot. The XYZ Y pipe with cat helped with it My setup rasps in the mornings, but after the cat is warmed up, it isn't discernible anymore. Then again, your Y pipe was %$400+ cheaper.

I've thinking to order this Y pipe for a good time now, it definetly goes into my list of most performance for your buck modifications. 50hp for under $2,000 (tune incl.) sounds good?

Where are you getting 50hp from a Y-Pipe from? :ugh2:

Woops, after a second look i think the rpm axis index labeling got cut off on that image. If you look at where the torque and rpm cross (5252 rpm), then you can count the bars from there. Really it looks like some power is lost below 2700RPM, which isn't that big of a deal in my opinion. If you are trying to go fast, racing or whatever, then you be above 2700 RPM 99% of the time anyway.

Oh if you mean the other blips on the torque(which actually show as gaps in the power graph), I think the inductive ignition pickup was getting some interference or bad reading, but if you look at the rest of the graph it's pretty clear where the curve really is.

The pipe is 2.5" to 3".

Yeah, that's what I was referring to. Yeah I'm not doubting it, it's pretty flat. :tup: Good gains.


The 2.5 to 3" is good, but now you just need to drop off the rest of the stock pipe cause you're choking up all that free flow you've gained from the headers/Y-Pipe. :(

Yeah I'm definitely planning on replacing the rest of the exhaust eventually. The idea right now is a custom single 3" pipe from the Y back. One step at a time... Hopefully with the right muffler/resonator combo it won't be too insanely loud.

Probably something very similar to TypeOne's custom exhaust

Overall with this car I'm trying to keep a very lightweight theme. Single exhaust should save a few pounds and single 3" will give plenty of flow.

I like the idea/look of the single exhaust. It just looks weird with our bumpers having the dual tip cutouts. That's the only downside.

Have you looked at, I believe Amuse makes a single exit exhaust for us? (I know you're looking for low cost, but just for an idea on piping/routing.)

Yeah I've seen that, "Amuse R1000" titanium single exhaust. Ridiculous price, something like $3K or whatever. Will definitely take that design into account, but really there's only so many ways to route a single exhaust. I'm actually toying with the idea of aluminum exhaust. Vibrant makes some all aluminum mufflers which could be used.

The only thing that makes me cautious of doing that is that I think the lightweight material could make the tone more raspy/ricy sounding.

It will probably carry a lot more volume with it too. Just due to the thinner metal.

Whichever you choose, just be sure to get 18" resonators if you want to reduce rasp. Most setups are fairly quiet at steady speeds and idle (cold starts are an exception). It's when the car is accelerating where it can get loud. I have a Tanabe exhaust and it's considered quet... not so much anymore with the PPE's and HFC

I still believe that after the stock cats, the Y pipe is the next most restrictive part of the stock exhaust. I saw great gains with my Tanabe Y pipe, and it looks like you got some nice gains too!

These are interesting gains. Nice gains but can it be? The tune itself could give up to 20 hp if I'm not mistaken. I just ordered one for the hell of it.

This is always going to be a gain over the stock pipe, but you should note that it's tuned Vs re-tuned, and not just tuned Vs tuned ;)

The merge point is why you lost a little power in the range, there is actually an optimum point at which the pipes should merge to optimize both figures. Hence the MD XYZ pipe merging earlier.

But even comparing to the tuned numbers (the first 2 pulls), those numbers are very impressive.

Why are there no links on google for MD XYZ? Are they a sponsor?

They're should be links everywhere, try searching Motordyne XYZ, I believe they are a sponsor.

Is it me or does this dyno plot look different than a VHR dyno plot. So many dips and valleys and a weird torque curve. Also putting down 322hp SAE with just headers and a y-pipe does not seem realistic at all either. Do you have a video of your runs with these numbers or a dyno plot chart with RPM listed?

Also, why does it show Runfile 31+ if you did 3 before and 3 after runs... Did they do over 28 other dyno pulls in three hours?

Yes, you're right, getting 8hp from an exhaust modification is absurdly impossble, it's all a big conspiracy. You can't make more than 300WHP on a VHR, all dynos are fake, all modifincations actually lose power, etc. etc.

would you see an issue with running this with AAM's short tails?

Not all that interested in replacing the entire CBE. More into the weight reduction/looks/sounds.

Never said the 8hp was suspicious, just the 40+ rwhp over a stock 370Z (~275-280rwhp SAE) on a dynojet with two exhaust mods and the restrictive can muffler. That and the unusual torque curve compared to typical VHR dynos (and your attitude..) lol

So what was your OEM dyno in SAE?

Actual dyno figures will vary massively, only delta matters, on top of that, this *is* tuned as well. I've seen quite a few people get this kind of power from tunes and basic mods.

Just curious about the OEM dyno overlay vs these mods is all, does he have that?

Seeing as they're completely different sections, probably not. If anything, this might result in some rasp, purely due to the resonance of a larger diameter of piping. I haven't seen anyone yet combine the short tails and any other mod other than TPs, which can be very raspy at normal cruising power.

I am also looking into doing test pipes along with the expanded y-pipe, but I'm extremely worried about the sound. The short tails can get annoying if I'm floating around 3k for whatever reason. It should produce pretty good gains though, since replacing the cats and changing the Y pipe pretty much converts the entire thing to straight piping. Headers would be the next step, although at that point, the sound would probably just end up being terrible in every way: loud, raspy, and with lots of drone. Sell everything off and get a CBE at that point, just for your own sanity.

Impressive gains -- what did it put down stock before the PPE headers?

If we assume ~275-280, the PPE headers made a huge gain over test pipes alone. Nearly double.

Your car will be INSANELY loud with a 3 inch single pipe coming out of that. I had one on my car and it rattled everything.

Stock I made 292WHP SAE in ~70F weather. Keep in mind manual transmission makes ~10hp more than AT to the wheels. Also I have non-sport package, so my brakes, wheels and tires are all smaller and lighter, ironically giving it more power to the wheels than sport.

What about the torque curve do you think is strange that it doesn't match other VHRs?

My attitude is that no matter how many dyno charts and information you provide, someone on the internet is gonna argue that "something smells fishy", "i call BS", "it's fake" or that I somehow have the only 3270Z that didn't come with a VHR engine or whatever the hell you are saying and it gets old.

My header thread here has stock vs header+tune dynos, but they were done months apart so the temp difference was about 20degrees. That's all the data I got and something people will just have to deal with.

I've seen now that the ambient air temperature does make a big difference on these cars. SAE and STD correction factors are designed to account for that difference, but the engine power output fluctuates beyond what those equations account for. Looking back, if the header before/after dynos had been done on the same day, the graphs would probably show a lot less gains. Still even if the gains were only say 20HP instead of 32HP, I would be perfectly happy with that.

The "before y-pipe" dyno from this thread was the same mod configuration as my "after headers" dyno in the other thread but the days/temps were different(80-85F for y-pipe runs vs 70F for after header run) so it was already about 9HP lower from that.

I originally posted STD corrected charts in the first post of the header thread. But since everyone cried foul I posted SAE version here: http://www.the370z.com/1494488-post37.html

I have custom single 3" exhaust now that I meant to make a thread about, but I never got around to it.

I went two magnaflow mufflers inline:
Magnaflow #11219 4x9 oval, 3in/3out, 14" length, 20" overall
Magnaflow #12619 6" round, 3in/3out, 14" length, 20" overall

A big oval magnaflow right after the y pipe and then a round can on the back. It's loud but not unbearable. I actually find it surprisingly quiet given what it is, a straight through exhaust with no cats. I didn't get before/after dynos for the exhaust.

http://i.imgur.com/AjKLlh.jpg
http://i.imgur.com/83YzAh.jpg

There's actually no evidence to support that... I can show you numerous drf's where they make the same power on this car, presumably due to the locking trans.

What was the actual cf? The mild weather definitely helped a bit too.

Anyway, regardless, the PPE's netted you a solid 20+ whp (or ~7-8%) , which is substantially better than test pipes alone (and that was all that I was trying to determine... :o )

EDIT: Okay, that CF was pretty high... SAE you would have been in the expected ball park. Either way -- really great gains with the PPE headers -- congrats!

I'd love to hear your exhaust. Please post a clip!