2.25" --> 2.5" MID-PIPE experiment...

[crispone]

^^^ Not much of a shot... but you "might" be able to see that the mid-pipe is now the SAME diameter as the TRD exhaust diameter. I had a local shop eliminate the section between the flange on the converter, (including the resonator), to the flange that connects to the TRD muffler. They retained the flange at the tail end so I can still make "changes" readily if necessary....

Initial impressions are:

NICE SOUND! I definitely picked up in "throatiness", without being annoying... and I believe I have better flow. Since I only drove a short while to run some errands, it's difficult to tell if/how much improvement I have gained. (It FEELS like I have gained... ESPECIALLY initial torque at lower RPM and "wind-out" power through the top end of the RPM sweep...)


I'll get a better feel after some more driving... and report on whether I've "caused" a "highway drone" or not.... jury still out on that one.


-crisp

[Sebas007]

How much it costs ?? I want my car to sound deeper (low tone)..does it helps to do so ?

[Biggi_e]

damn crisp you got ahead of me! i was going to do the same exact thing. can you post a sound slip please when you get some time?

How much it costs ?? I want my car to sound deeper (low tone)..does it helps to do so ?

hey if you come down to my area for another meet sometime, my buddy will only charge for the welding. ill just buy extra piping when i get mine done.

[Sebas007]

damn crisp you got ahead of me! i was going to do the same exact thing. can you post a sound slip please when you get some time?

How much it costs ?? I want my car to sound deeper (low tone)..does it helps to do so ?

hey if you come down to my area for another meet sometime, my buddy will only charge for the welding. ill just buy extra piping when i get mine done.

Great great buddy !

[crispone]

Guys,

SOUND is definitely DEEPER and THROATIER.... but NOT obnoxious or excessive... it's more of a "subtle" improvement in resonance and frequency, so I have no reservation encouraging you to try it if you want to improve your sound without compromising "class".

PERFORMANCE!

I am PLEASED to announce that after yesterdays brief driving and todays commute to work on the highway (including triple digit speed cruising... in the interest of R&D feedback, of course!), the effect appears to be across the board improvement, (subtle, but it's there...), in the low, mid, and high end. The initial throttle application TORQUE under "gentle" peddle depression is most evident, and smooth torque-based responsiveness throughout the REV band in all gears. I truly think the car is stronger everywhere from this simple change! (Perhaps it is complimenting the CRISPMONGO AIR FILTER? --> MORE air IN with LESS resistance... MORE air OUT with LESS resistance... pretty basic.)


PRICE!

Best part! I have a local shop where Marty and Amos did the job for $125 + tax! (Less than 90 minutes from when I pulled up 'till I pulled, er... PEELED OUT of the drive!)


-crisp

[Biggi_e]

damn thats a lot! my buddy thats been my mechanic for years knows how to weld too, the piping should be around 20-40 bucks and welding fee for me is free! but i still pay him a little for doing it, so i say total cost around 60 or 70.

crisp, is there a deep drone noise at high rpms?

what kind of piping material did you use?

[Sebas007]

I know the principle of power gain for old engine...more air...more fuel...less restriction = BIG BOOM !!!

For modern engine control I thought the balance of pressure in the intake, engine and exhaust system had to be respected...because you could create a power loss.

I'm just curious to know about it.

What kind of stainless steel did you use ?
They provide the pipe, bend, cut and weld this custom part for 125$...nice deal I think !

[Midias]

Yea I did mine about 3 yrs back with 2.5 inch piping and a TRD muffler. I found it was a little loud cruising on the highway so I used a glass pack as a resonator very high flown and nice noise suppression. Worked great all together and I welded it my self all very easy to do.

[Down2TheC]

Ummm... isn't it 2.25 going into the cat? If so, then all you did was remove the res. Fluid dynamics would say that the smallest point/greatest resistance (cat/muffler) would need to be altered to cause more air flow. Changing the pipe diameter downstream should have minute(no) effect. I wanna hear Brian's take on it.
However the resistance (static head) of the various components is additive so removing the resonatore and replacing the OEM muffler both help.

Regardless, glad you're digging it.

[crispone]

^^^ I'm told the resonator restricts down to 2" inside... so at least THAT constriction is reduced... with respect to the "fluid dynamics" principles at work... you WOULD have to ask Brian! All I can say is... even JUST the TRD improved performance, and it was a "straight thru" design with increased diameter... furthermore, don't hot, expelled gasses expand? By allowing them to "expand" and flow more freely "sooner", don't you benefit after a certain "threshold" of pressurization past the pre-cats and main cat so early in the plumbing? (Given the BALANCE of the remaining plumbing is a "consistent" diameter?) I'm just speculating on this last point... but seems to make sense to me... (Then again... I DIDN'T sleep at a Holiday Inn last night... )


Sebas, as for BACK PRESSURE and BALANCE, I AGREE... however, in that this is a fairly "mild" change, and there IS a little "KINK" or "RESTRICTION" on the pipe JUST AFTER the cat (some kind of "reduction" in diameter to nearly 2" or so?)...combined with the fact that the pre-cats and main cat provide plenty of "backpressure" to maintain the "scavenging" effect that "MAY or MAY NOT" be taking place within the plumbing design as intended... I am SURE I have not LOST any performance... and it DOES sound a little better. (I would have to SWEAR by my BUTT-DYNO that there are subtle gains...)

BTW, not STAINLESS or anything fancy... just basic muffler shop stock plumbing... but I still think it was a VERY fair deal for a buck and quarter to get the piece carefully cut, bent, and welded to my existing flanges in just over an hour without an appointment or anything...

Well, I gotta go VROOM VROOM now!


-crisp

[PXLpainter]

Hey Chris - sounds good - was considering doing the same thing too after the headers/Y are completed.

JP said the OEM cat is already a high-flow in their opinion.

Should have more info/pics on that setup soon as well.

Would be cool to get dyno numbers on all of it...

[crispone]

Hey Chris - sounds good - was considering doing the same thing too after the headers/Y are completed.

JP said the OEM cat is already a high-flow in their opinion.

Should have more info/pics on that setup soon as well.

Would be cool to get dyno numbers on all of it...

Yeah, the headers and "Y" would really complete the package! This setup enables that to "bolt right in" with the changes I made... so it's all part of the "PLAN"!


Keep us posted at your end... we're all waiting for the headers!


PS: I DID ask my shop about the silly "crushed Y" that we have now... and they just didn't have a good solution for it. I told them JPP MIGHT be working on something, and they agreed that would be the BEST solution.


-crisp

[Down2TheC]

^^^ I'm told the resonator restricts down to 2" inside... so at least THAT constriction is reduced... with respect to the "fluid dynamics" principles at work... you WOULD have to ask Brian! ...

Then that resonator should go. And I always refer to Brian because the exh system is a tricky bitch. Logic and physics don't always apply. For instance...you'd think that bigger is better but at some point you're cooling the exhaust gas making it more dense and harder to push. (somewhere over 3" for us)

Brian knows all the rules after years of working with the things.