Webcar and me have been debating if the elimination of the H pipe would hurt the performance of the Borla Exhaust.
At least the anoying noise has been eliminated I mean the one of the resonance on the H pipe conection.
It sounds better on our opinion.
What do you think on this course of action?

 

I would replace it with an X-pipe if possible.

 

I fully agree with that. Magnaflow makes them. And one could copy stillen's type of X pipe by butting 2 flowmaster Y-pipe's together >-<.

I picked up that Acosta Racing Y-pipe with the Magnaflow high flow cats built in and I plan on making a true duel out of it, so I've been researching this whole H pipe and X pipe thing. X pipe all the way for me

 

Only a dyno can tell you if the H or X is better. And you can't rely on other people's dynos unless you are using their exact specs in your custom exhaust setup.

Our cars need backpressure so if you are going for a wide pipe then go for the more restrictive setup. Either that or do the reverse... smaller pipe with low restriction.

Getting it right is where all the power is too be had.

If you look at the Hi-tech exhaust pics posted up here a few weeks back it has an interesting setup instead of a traditional Y pipe. It runs 2 pipes from the manifold into the resonator, one out.

I know our cars are JAP spec so they are different but we all gained over 20 rwhp out of it.

Hope i didn't go too off topic...

 

Carlos and I have the feeling that the car is a little slower, but is just a feeling... I race w my brother yesterday and the race was very close... but he have everything that I have except headers (he have Injen exhaust) so is a little hard to tell... tomorow I'm gonna take some action about this matter... I will let you know!

 

This exhaust is very interesting, its a very good looking system, the HP is impressive... I believe that Japan Spec have the same exhaust system that US spec, the difference in power is from the ECU... correct me if I'm wrong!

 

Technosquare should be able to answer that one, they got their hands on a Jap spec ECU when they did the tuning.

I don't think there is much in the ECU here in Australia as we have worse fuel than JAP and USA. It would be very hard for them to just lean us out or advance timing.

Also considering that we are only 206kw and not the 214kw in the US it kind of tells me we are detuned for our market. Detuning is done in the ECU not the exhaust...

Thats why I think Hi-tech may have just built the right combination for our car. I'm still curious to see what it would be like on the US cars. Hope someone in CA gives it a go and posts a dyno chart up.

 

Why do I need a dyno when I know what one does over the other? The H-style crossover is good at balancing sound pulses between the two halves, but does little to promote scavenging because the exhaust gases tend to follow the path of least resistance, which is straight through each pipe rather than taking the 90-degree turn through the H-pipe into the other half of the system. In an X-pipe system, however, where the two sides of the system intersect, the gasses have no choice but to intermingle as they pass through the junction. This promotes improved scavenging effects by smoothing out uneven exhaust pulses from the engine’s firing order. It also helps quiet down the exhaust, resulting in a mellower, less raspy tone. The stillen's X pipe adds up to why they dyno'd as high as they did, in spite of using their rather large 2.5" pipe diameter on their true dual. So this isn't just about a high dyno, it's about what part function's better than the other.

 

I put the H pipe back (welded) and the car put 10 rwhp 10 tq more in the peak HP so if you want to eliminate that "raspy" sound just weld the H pipe.

P.S. a free tip!

 

It got rid of the airy flutter i hear?

 

I too got tired of hearing that "airy flutter" so I went down to the exhaust shop and had that thing welded in. The welder and I also noticed that there was a small leak at the H-pipe as well. The exhaust sounds soo much better and no more annoying flutter -Ricky-

 

I have read many places that engines needing backpressure is a myth. Why would the Z need it? Backpressure would equal resistance to the exhaust flow, correct?

One person attempted to explain this by the following:

Take the core from a paper towel roll and blow through it. Now take a straw and blow through it. Which provides better flow? Well obviously, the air coming out the straw will be moving faster, but who's to say that the volume of air coming out of the bigger paper towel roll isn't higher? Just some food for thought.

 

as with webcar my car gained back 10 hp at wheels and 10 pounds of torque. I must say I was frusrated thank god this issue was resolved. Though I wish greedy came out with their exhaust

 

I'm glad for you

 

Tomarrow I'm going to go weld the H-pipe, but did you guys weld the entire system together at all the clamp sections? I don't quite like the idea of clamps to hold an exhaust system together, but just curious in. I also have the notirous rev 'n air flutter that comes as the rpms go back down. It _sounds_ like it's coming from the H pipe as well. But my $hit also rattles, so I gotta track that down to. I think for now I just might weld the h pipe and see if that fixes the not so koo kid raspiness along with the air flutter. Thanks so far for your guys's input!

--Justin

 

Carlos welded all the way, I just weld the H pipe and the pipes after... if you weld the H you gonna hear the rev 'n air flutter that comes as the rpms go back down but less then before... that sound is when the air of the two pipes colapse in the H, so you are gonna hear it just a little bit now!

P.S. Tip for everyone, you have to weld it by a electronic weld machine because the SS is more cold than the ordenary pipes (that have the muffler shops)... just make sure the muffler shop can weld SS...