How important is the Y pipe type?

[V6Celi]

So one of my winter projects is to buy or have built a better Y pipe. The exhaust post-cat is nice but the Y pipe is crap thanks to the local exhaust shop. There seems to be 2 different types of Y pipe and I am wandering which is the best design for performance. There is the type referred to as “dats” which seems to be just a pipe from the front bank to the cat with a short pipe from the rear bank connecting to the top of the pipe. A very simple design (but all examples I’ve seen for sale are overpriced for the design). The other design is like the “OBX” pipe which appears to be a Y pipe with both the front and rear banks having an equal length pipe before the merger of the two. Does anyone know which type offers the best overall performance, mostly for power? Has anyone dynoed the different types to find out? If this has already been discussed, just point me to the thread as I was not able to find an answer using the search facility.

BTW, my motor is the 1MZ, but it seems the answer would be the same for any V6.

Thanks, Jim

[Mr_Krispy1183]

Dat's pipe was just meant for those who retained the stock exhaust mani's, whereas the OBX/JP Performance design were designed as full headers from the primaries to the y-section.

[V6Celi]

Dat's pipe was just meant for those who retained the stock exhaust mani's, whereas the OBX/JP Performance design were designed as full headers from the primaries to the y-section.

Thanks for the reply. I did see this when looking at pix of the different types of Y pipes. The factory used an OBX style Y pipe (although not as nice) with the stock manifolds, so I think the better performing design would work regardless of whether you have headers or not. I my case, the early “shorty” header style factory manifolds are the only choice I have without building custom headers (a future project).

[Chinky420]

also, dat's it's a slightly smaller diameter pipe (i believe 2.5" or 2.75"), rather than the OBX which is a 3" pipe.

3" pipe causes a loss of backpressure resulting in a theoretical loss of torque.

2.5" (I think that's what it is) maintains some backpressure, while not suffocating the engine.

but also what krispy said above, dat's is meant to bolt up to the stock headers (with minimal modifications), while the OBX is a full exhaust system based on the JPP set (headers+y-pipe)

yeah, the stock y-pipe is atrocious...even something as simple as a fabricated 'dats' style y-pipe would yield you some gains.

[Chinky420]

(sorry for a double post)
the 3" pipe is better for forced induction, while a 2.5" pipe is better for NA engines.

surprisingly, my dat's y-pipe doesn't have too many problems with turbulent exhaust flow causing inconsistent performance. no backfiring, no popping in the exhaust gurgle, etc.

oh but i also think i have an exhaust leak, which may (or may not) help with alleviating turbulent exhaust flow.

[Midias]

OBX headers have a 2.5 inch pipe NOT 3 inch. The Dat pipe and obx are about the same. I think a lot of people get confused because the OBX exhaust is 3 inch. I think dawgs gained over 20whp going from cali manifolds to federal with a dat pipe and a magnaflow cat.

[hskrsolara]

^^Correct. i did not feel any gains going from my OEM manifolds with Dats pipe to OBX headers and OBX y pipe. However, I just put on the OBX 3" exhaust, so hopefully that will show up on the next dyno. Personally, I feel that the OEM manifold with Dat's y pipe is the best performance bang for you buck out there.

If I had to do it again, I would have stuck with my oem headers, dats y pipe, and OBX 3" exhaust, also knowing that I am going to 6 psi.

For NA, I loved my greddy evo2 with dats y pipe and OEM headers.

[02slera]

Thats interesting. so there is no real reason to put headers on this car? the stock exhaust manifold is just as good?


From what i have read here about the Y pipe... any upgrade is good as the stock one is not good, so go with whatever is cheaper.

[V6Celi]

^^Correct. i did not feel any gains going from my OEM manifolds with Dats pipe to OBX headers and OBX y pipe.

Well, it's good to know that the OEM "headers" aren't that bad. I suppose it's also good to know that the Y pipe type doesn't matter as long as it is not the stock Y pipe.

Thanks for all the replies.

[jetbtkng]

headers are always better than stock, period, the stock exhaust is crap, and if your boosted you want a setup like obx or simular, 2.5in just not good enough when your going to run bigger boost, i gained 32.5 hp with obx complete exhaust...................

[SleeperSolara]

Thats interesting. so there is no real reason to put headers on this car? the stock exhaust manifold is just as good?


From what i have read here about the Y pipe... any upgrade is good as the stock one is not good, so go with whatever is cheaper.

Not true at all.
If you look at the OEM 1MZ header it's design is horrible.
If you look at the OBX version, the flow design is way better.

[Eye8Pussies]

the stock headers aren't terrible...the stock y-pipe is terrible, the stock headers just don't have high-smooth flow in mind, which is similar to most stock manifolds- they can be cast, which means crappy merges

and the obx headers are def in a huge improvement


hskrsolara -> if you didn't feel the difference between stock headers and the obx ones, you either didn't tune it, or your tuner doesn't know how to tune properly

[jetbtkng]

^ i was going to say the same thing, but im trying to be a good boy, lol.............

[hskrsolara]

well, you guys can say what you feel, we're all big boys here.

What I am saying is what I saw with my own eyes, on the dyno with about 3 hours of tuning. We all know the stock manifold "design" is crap, but I am challenging how much that contributes to loss of horsepower. The y pipe is easily the biggest bottleneck on our oem system. My problem was I was not able to perform the header install myself, due to lack of time and lack of a lift. So, I paid my mechanic to do it for me, which rarely happens with anything on my car. I have a big chunk of $ invested in those OBX headers and y pipe now.

Personally, I think your $ goes farther with a Dats y pipe and 3" exhaust, simple mods that anyone can do with minimal equipment. Not that 1 option is way better in performance than the other.

I'm just saying that, on the dyno, I showed no gains from going to the OBX headers and y pipe, from my Dats pipe and OEM manifolds. Both dyno's had the Greddy EVO2 exhaust. Now I have the full OBX system, per Frank's awesome reviews, and am hoping the new bottleneck was my Evo2 exhaust, and now that is eliminated. If I had a digital copy of the dyno, i would post it, but I dont. I don't have time to make crap up, im calling it as it is.

Now, the 1 thing i forgot to mention is that the other mod i made, between dyno visits, was the supra BBK. I wouldn't have thought it would have caused any decrease of whp, but it is a possibility since the supra rotors were much larger and heavier than the oem. Even if it was the cause, I dont care, cause I love the stopping confidence that I have now.

[Chinky420]

OBX headers have a 2.5 inch pipe NOT 3 inch. The Dat pipe and obx are about the same. I think a lot of people get confused because the OBX exhaust is 3 inch.

whoops, thanks for the fact checking!