Huge low end loss with H pipe

[KungFuHamster]

i didnt notice any power loss down low at all with the addition of my O/R X-pipe. i had the car retuned via email tune from BBR and it runs great.

i think its in the OP's head.

 

[2011IngotGt]

What mufflers were you running?

Well, I put the stock mufflers on to test the low end, and it seemed like I got all my low end back. BUT it sounds too ricey and muffled like that, and the tips are too small. Now I'm frustrated. I might end up taking off the h pipe and selling it.

thanks

 

[Boss281]

My car hauls ass and I can't say I detect any low end loss. The Boss mani and CAI/custom tune was a bit of a dog, but adding the Lethal h-pipe really woke it back up, and moving from 3.31s to 3.73s really made this thing crazy fast on the road again. It's loud as shit and I'm swapping the Hushpower muffler for a GT500 muffler in an attempt to find something less drone prone...

 

[MikeVistaBlue06]

You reduced back pressure so it it follows that low end torque would be affected.

He actually increased backpressure by increasing the dynamic sonic resistance portion of the impedance aka the "AC" portion if you're into electronics. There is a soundwave hitting and forming a resonant node that is pushing back on the low end. That hampers the engine from making power.

Same principle that is used to cut pipes for pipe organs--the length and diameter of the pipe will determine its natural or resonant frequency.

Just remember "More's Law" doesn't always work. When you look at a pipe and think bigger is better, you are correct for the "DC" steady flow condition. However, we send pulses of gas down these pipes and they behave much differently than a steady stream. Something bigger may not be better.

HTH

Mike

 

[FalconGTHO]

/\ Good to see you back, Mike.

 

[pacettr]

Top end for sure, but it would go sideways when shifting 1-2 and 2-3 every time even half throttle. Now, it's a dog until it gets to at least 3rd.

Not a huge deal, but I'm a fan of nasty low end power, I don't get to 130 mph too often

This made me lol...

i didnt notice any power loss down low at all with the addition of my O/R X-pipe. i had the car retuned via email tune from BBR and it runs great.

i think its in the OP's head.

werd

 

[Fullboogie]

I gotta say, my car does seem to have some low end loss with my O/R H pipe. So much so, that I put the stocker back on, removed the oval Maggies, and went with Stingers. Sound isn't quite as good, but the positive change in low end is enough for me to keep the current setup.

Wonder if it has to do with whoever's tune is in the car?

 

[MikeVistaBlue06]

Another thought is that a larger setup may change the scavenging effect, such that it takes more airflow in a larger pipe to re-create the same scavenging effect of a smaller pipe thus it makes more power on the top end.

You can think of this it terms of toilets (of all things). Some flush better than others, all other things such as water level, etc. being equal. The reason is the scavenging effect or the ability to setup a "suction" at a given flow rate.

HTH

Mike

 

[Jared@Lethal]

Just curious. For those that seem to think they lost power down low have you actually done any testing on a dyno to validate an actual loss? Or are you just basing this on feel?

If dyno testing was done can you please post your graphs. It would be very helpful to others to see actual proof of a loss rather than an opinion of loss.

If it's based off of feeling or opinions alone that's not very good data. Not trying to say that there's no way you could have lost power but without any actually testing there's really nothing solid to back it up.

Jared

 

[Boss281]

FWIW, my Lethal h- actually gained some of the loss caused by the Boss manifold. Runfile8 is before the hpipe at 393hp, the hpipe went up to 399. Gains were higher in different parts of the curve:

 

[Bmr4life]

FWIW, my Lethal h- actually gained some of the loss caused by the Boss manifold. Runfile8 is before the hpipe at 393hp, the hpipe went up to 399. Gains were higher in different parts of the curve:

How do you guys get electronic copies of your dyno runs? Do they put them on cds or something? Email them to you?

 

[Boss281]

I installed the free DynoJet WinPEP program, and Woodbine Motorsports just either sends me the files or sticks them on a thumbdrive when I'm over there...

 

[Bmr4life]

I installed the free DynoJet WinPEP program, and Woodbine Motorsports just either sends me the files or sticks them on a thumbdrive when I'm over there...

Awesome, thanks.

I plan on getting a few runs done.

First 3, stock, Bama Performance tune, Bama Race tune.

Next 3, Bama Race with H, Bama Race with H and JLT CAI (gotta be quick with the swap out), and some random pull.