Kilroy's 99 TA

I would think that putting longtubes on a car and keeping the stock Y is like putting a wider seat on your toilet....

won't really help increase flow!!!

Bad Habit Bird

iTrader: (12)

The car actually made a lot more power and sounded MUCH better with the longtubes on it. So you think that it wont make any difference if I change to a larger Y-pipe?

McRat

Some folks may call BS, but I dyno'd a stock 2000 SS before and after 2.5" custom Y install. 15rwhp. Got witnesses. Not sure why it gained so much. But it showed up on the track as well. Cut 0.13 off my ET. 13.01-12.88.

Bad Habit Bird

iTrader: (12)

was the 2.5 Y you had made mandrel bent?

Bad Habit Bird

iTrader: (12)

As of right now I have basically every bolt on for my car right now, but when I installed the Grots I just had my factory Y-pipe modified so it would work with the headers.

So my question is how much of a gain would I see from taking off the factory Y and going with a 2.5 or even 2.75 Y-pipe?

RPM WS6

iTrader: (3)

[quote]Originally posted by McRat:
<strong>Some folks may call BS, but I dyno'd a stock 2000 SS before and after 2.5" custom Y install. 15rwhp. Got witnesses. Not sure why it gained so much. But it showed up on the track as well. Cut 0.13 off my ET. 13.01-12.88.</strong><hr></blockquote>

Did you use a FM Y collector? Did you remove/gut the cats at the same time?

McRat

Heck, I drove into a muffler shop and told them to make me 2.5" Y-Pipe and throw a cutout on it. I went and had lunch. Came back and there was an Aluminized Mild Steel 2.5" Y stuck to my bone stock cats and a 3" Zed-style Cutout. I assume it was mandrel bent, how else would you bend it? Then I drove to the dyno.

Cost ~140 intalled. Looks good, fits good. Dyno'd +15 capped, +18 open.

Something does sound fishy, because no one else is getting that big of gains from a Y-pipe. Even SLP, "King of the Inflated Horsepower Claims", says they are good for 5-8.

I'll take it though. I'm no dyno-racer. I test the car on a dyno, then run it at the track. So far, the dyno agrees with my results. My theory? I don't have one. It doesn't make sense.

99 Black Bird T/A

iTrader: (4)

[quote]Originally posted by McRat:
<strong>Something does sound fishy, because no one else is getting that big of gains from a Y-pipe. Even SLP, "King of the Inflated Horsepower Claims", says they are good for 5-8.

I'll take it though. I'm no dyno-racer. I test the car on a dyno, then run it at the track. So far, the dyno agrees with my results. My theory? I don't have one. It doesn't make sense.</strong><hr></blockquote>

I think the slight increase in exhaust flow bumped your A/F ratio in the direction it needed to go and the change in A/F resulted in most of the gain. Did you have A-tap logs that might show a A/F change?