milelin

When I first saw exhaust depo’s y-pipe dyno, I just thought this was too good to be true as it was the exactly the same design fujitsubo made for the later generation VQ35HR and it made very minimal differences.

http://www.fujitsubo.co.jp/product01...00000000003927

So to find out, we made a very similar design. It is not pretty by any means but it serves the purpose. The diameters are the same with exhaust depots and the results are as follows:

http://memimage.cardomain.com/member...56_47_full.jpg

This is an average of 5 runs and the results are similar to fujitsubo’s. I will say it was a bit hotter compare to our baseline but even with the weather correction it would not be close to the dyno posted earlier. It is actually quite logical if you think more about it. Stillen, FI and others are supplying their full cat-back making 5-10whp so its impossible a y-pipe will make that much power.. given that their y-pipe is similar to stillen’s anyways. So overall, there will be gains for this mod but more like the 2-4whp range mainly in the upper range. This is not to say exhaust depot is fixing their results in anyway. It’s a great company making good stuff at a good price. Just wanted to share honest opinion with people interested in this mod. Probably just some error during the pull cause dyno reading can vary greatly from how you give throttle etc…some of u might noticed that in that dyno graph, the fuel cut off point are very different.. seems like the curve has just shifted to the left rather then up.

Some pics of our y-pipe:

http://www.cardomain.com/ride/437656/7

Black Betty

iTrader: (60)

Thanks for the insights. Did you fabricate the High Flow Cats or did you buy them from a vendor?

milelin

the HFC are from Berk. Nicely made but apparently quite rusty already only after 2 months of use..

ucla bruin

iTrader: (7)

Thanks for sharing. Do you guys sell any parts?
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote

milelin

yes. but more of a OEM/ODM nature.. we only do volume sells. I noticed there are a few vendors here, if any shops that are interested in making their own parts, please PM me for details. We do a wide range of internals and suspension components for some of the biggest brands in the business.

MaxToTheG37

iTrader: (3)

Wow were do you live... I have had berks for 4months and they only turn a purpleish orange color due to the heat...

I would put money on it saying that is what you are seeing...

No One has said anything on here about rusty HFCs and theres prolly 50 people with HFCs from FI and Berk on here...

so i give a big

UNV-IT46

iTrader: (3)

who's making 5hp for a cat back? I was the one who dynoed the y pipe and it pulled the same HP gains every pull. 4.91hp at peak. just under 15 throughout the whole curve.

vinnys coupe

iTrader: (1)

hey unv did u ever get dyno the full exhaust?

UNV-IT46

iTrader: (3)

no we've been swamped here at the shop. I am hoping to get it on today

milelin

i live in taiwan and it does rain often here so maybe thats the case..however, i will say that they really put effort into the kit, i actually met bryan from Berk in our booth in AMPA this year (AMPA is a auto parts show in taipei) and told them the gasket was top notch, it was cut by a water jet cause they use really thick copper which will be hard to make from a press tooling.

As far as the finding goes. i am just showing you wat we actually found. Maybe exhuast depot does make a 15 whp y-pipe.. Sooner or later futisubo will come out with a very similar setup and it will show very similar results. i mean, why would i want to show lower numbers on something already on my car and something that we will soon mass produce. just my 2 cents.

Exhaust Depot

The dyno numbers posted on the ypipe are SAE which means they are corrected. The dyno numbers you guys showed are STD which is uncorrected and always reads higher than SAE.

Dont take the dyno numbers from me though, it was dynoed by an independent company. Plus look at the results others have posted about it. They feel a nice HP difference. Also the claim is 5hp peak, not 15peak. Its 15 or so under the curve.

The ypipe is more restrictive than the ypipe back setup from what I could tell.

milelin

yeap, i guess we will just have to wait for someone to dyno theirs to find out.

milelin

Just an update on the y-pipes, few days ago, we had the piece removed for more testing as we are planning to come out with another design and immediately i can feel the increase of tq with the O.E pipes back on. This is especially felt when crusing. I do have the HFC so we are suspecting that further reducing back pressure wasnt a good idea. My center pipe is stock.

I know our dyno shows small gains but that was on 4th gear with the padle to the floor. plus this car is electronically throttled which made things very complicated when it comes to real life driving. Well, the truth is, the car does have much more usable tq under normal driving conditions with the O.E y-pipe back on. Looks like this will be hard one to match..

Also, just for reference, the O.E y-pipe has a 2.5 opening connecting to the center pipe, the 1.75 is only for the sections following the cat. We will try to make some changes and hopefully we can get something to work well in all conditions or else we will have to scape this project. Also, unlike the O.E cat, the O.E y-pipe is very light already, a stainless steel part wont make much difference in weight

KAHBOOM

iTrader: (4)

Ya I was thinking the same thing. With both HFCs and y-pipe, you would reduce backpressure. With one or the other you get enough additional flow for more HP but not so much that you reduce backpresure.

gan78mao

iTrader: (1)

hey milelin, i thought u had Greddy exhaust before?
how much did those fujitsubo run u?