Y-Pipe & Exhaust commentary
Dec 2007 when the 2008 XP was released, I was at dynotech Jim's in Batavia NY just after he spent several days prior testing y-pipes I asked him "what's the scandal on these y-pipes Jim?" and said this to me; Looking through the window and pointed to the puddle on the street and said, "I could piss in that puddle and yeah it would raise it a bit, but could you tell?" had a gruff "harumph". Some Y-Pipes married to a complete package did show gains; and sat down and that was about all he mentioned.
I am not savvy on these sorts of subjects; however what I could sum up is that HP gains are by virtue of rpm changes and/or flow ability and/or how tight/loose the pipe is for the application.
The question arises - what job does the y-pipe need to perform to make different power than stock. What does it do to make such a claim?
I sell clutch kits to a lot of sled owners out there and can claim to see/hear/know of just about any mod you can think of regarding exhaust, my summation would be that the customer has to beware there are exh systems for elevation ranges. Where are you're driving your sled at elevations and is this system suitable for your requirements?
Pipe, Muffler & elevation commentary
Like a certain exhaust pipe that calibrated for 3000 feet and higher; (Thanks to Mr. Holt’s test)
Test #1 - The owner tries to run it down at low elevations, 2200 feet and at full throttle reveals proper rpms for a certain time, then eventually the rpms diminish by 200.
What is happening? People blame clutching right off the bat - hold on, you're right, it is the clutch calibration because what you are calibrating for won't work with that pipe. The clutch calibration wants to work with an engine whose rated rpms don't want to change but possibly in this case, the pipe's power shape moves around with temperature variation and changes the rated rpms it wants the engine to run at.
The pipe wants to run at 8200 rpms until a certain temperature and works with “X” flyweight but after a certain time of full throttle the pipe wants to run at 8300 or higher and now the pinweight is too heavy to achieve 8300 - then the rpms diminish because the pinweight is now heavy, the pipe wants the engine to run "late"
As Jim mentions, "The pipe is too tight" for low elevations and wants to run at a higher rpm than you are trying to calibrate for. The pipe will deliver 8200 rpms for a certain pipe temperature range (and time limit at full throttle) then the pipe gets to a higher than stock temperature range and now the rpms diminish.
The pipe does not want to run at 8200 at low elevation, it wants to run higher rpms.
The pipe changes the engine personality "rated rpms" as temperature increases.
You have to change clutching but is this possible with what's available?
Test #2 - The owner puts the stock pipe back on and makes the same run to peak track speed in the snow and holds 8200 and run harder and longer time and on and off the throttle with a "come on you sucker blow up...." attitude and still 8200, and higher track speed.
Test #3 - install aftermarket exh back on and just like as if on the timer, 8200, 8100, 8000 and hang there.
..What is verdict?
Don't quote me on anything I say, if you are digging into getting aftermarket exhaust systems, need to do "due diligence" and have answers to questions for your particular situation/elevations.
Q) What will this y-pipe do for me?
I can say I can think of one 08/163 that is bone stock engine however a complete Y-pipe/pipe/muffler package and this sled could run in one lower clicker number holding 8200 rock solid than the other sled's with similar clutch kit in clicker 4.
Some of these exhaust packages work quite well and as advertised.
Is the y-pipe worth the $ if you can’t prove power increase before and after on the dyno on-your-own-engine?