dropped the exhaust for local track night...will never run open d/p EVER again.

[91tizzy]

1) I read about the vibrations.....but holy shit
2) Ran like total ass. (Im thinkin my knock sensor was pulling timing like crazy)
3) Loud and obnoxious (this was expected)
4) did I mention the vibrating?
5) how about the noise?

ok yall get the point.

All in all....not for a street car. Unless you enjoy loud and obnoxious.
I know Im not tellin most of you anything and I DID know better than to do this but figured what the hell, might as well see for myself.

Just thought I would forewarn anyone thinking about just droppin there exhaust on mostly stock car to not do this.

There is a plus side to this...i determined I have a slightly bigger downpipe and some owner prior to me hollowed out the cat before I got the car. AND the axle back pretty much fell off when I started droping it....held on by one rusty bolt.....so cant wait to bolt up my exhaust and hear it with no leaks and feel my car pull half way decently again.

 

[HIGHPSI4]

Yea, that is rough. Just got to get those gases out from under the car.

 

[TurboATM]

i had mine open at d.p for a week or 2 during the summer just for the fun of it, cruzing the blvd...nice and easy, but still able have a loud turbo spool to show off... and was it loud

 

[fulanititoo8198]

Yea what were you expecting it's going to be loud.

 

[bmoha2]

did it produce any more power or what it having too many issues pulling timing?

 

[91tizzy]

Absolutely did not gain a dam thing beside decibel rating. Dont get me wrong I loved hearing that beautiful wistle but the vibration sucked more than anything and actually lost usable power. would pull almost fine at boost but lost all the part throttle feeling of spoolin down the road. It was either go or no go thats why I think it was pulling timing out bad. I figured the drop in backpressure would help her out but it sure didnt....

yeah and I did expect the noise and I kinda liked it....so that wasnt anywhere near the issue. The vibrating/ power loss was.

 

[bmoha2]

Thru the exhaust I mean. I embarrassed myself when I asked a co worker what the whine was coming from his Ford turbo diesel. He has a monster four inch exhaust on it. He said it was his turbo. And I was like Woah! I don't ever hear my turbo like that and he said it was because he had a big exhaust system on it with no cat. Makes me wanna delete my cat!

 

[TurboATM]

i didn't really lose much of anything except low end and spool time...i gained a huge amount on top end pull

 

[Car Cannibal]

How are you reading your air fuel ratio and knock retard?

It's hard to believe that you can drop a lot of backpressure and not gain any power.

 

[habitatguy187]

You WILL NOT lose any noticeable low-end power with a bigger exhaust, this is one of the famous DSM myths... comon' people. Search and you will see this has been proven time and time again.

 

[TurboATM]

well it did cut my spool time, but gained top end very much so.


and sounding like a jet passing by was amazing, i loved the face of BIG trucks as i roared by

 

[dsm-onster]

If you don't have a true cold air intake, routing out of the engine bay. Or at least the STOCK airbox on unhacked. Then you lost power because you were putting low oxygen very hot exhaust gases in your intake. This would explaine the knock too. Since your intake temps probably went up 25+ degrees.

I gained airflow throughout the rev range going from open 3" exhaust to no exhaust. I had a proper cold air setup, too. No loss in throttle response or power at 3000rpms.

You could very well have a proper setup cold air intake, but dropping the exhaust works for most of us.

 

[JusMX141]

You WILL NOT lose any noticeable low-end power with a bigger exhaust, this is one of the famous DSM myths... comon' people. Search and you will see this has been proven time and time again.

Really? I must've been imagining that my car lost a considerable amount of off-boost torque when I went to the 3" Thermal R&D system that's on it now versus the stock turbo-back. Sure the turbo spools 100rpms sooner, but I could've sworn I had some off-boost torque before where there is none now.

Thanks for clearing that up for me.

 

[dsm-onster]

But Justin, he has a 14b. Which sees 15+psi by 2800rpms. When is he NOT in boost?

 

[JusMX141]

I think I was running a Big 16G at the time....like I say, I'm not complaining- obviously I picked up a considerable amount of power once the turbo did spool, but it definitely lost some off-boost torque.

 

[TurboATM]

But Justin, he has a 14b. Which sees 15+psi by 2800rpms. When is he NOT in boost?

i have Justins old 14b...been beating the living hell out of it for 2 years now and still not 1 problem

 

[Car Cannibal]

Jusmx141, did your boost gauge read higher when you swapped exhaust systems?

 

[dsm-onster]

Mine did, when I dropped the exhaust. I had to reset the boost controller before I logged those results I posted above.

 

[Black_Bullet]

I run open DP, I have a 3inch electric cutout on end of my 3in megan DP and when I have it open it doesnt vibrate that bad or sound too loud. Sounds very deep and aggressive and sometimes the turbo whistles .
Honestly the more I turned up the boost the quieter the exhaust drone got (though it spooled much louder)
When my cutout is closed I just sound stockish though since I left the stock muffler.

 

[No_Skillz]

How does running open DP increase vibration?

 

[dsm-onster]

I run open DP, I have a 3inch electric cutout on end of my 3in megan DP and when I have it open it doesnt vibrate that bad or sound too loud. Sounds very deep and aggressive and sometimes the turbo whistles .
Honestly the more I turned up the boost the quieter the exhaust drone got (though it spooled much louder) When my cutout is closed I just sound stockish though since I left the stock muffler.

Yep same with me. Because you're routing more exhaust gases through the turbine wheel instead of wastegating them.

 

[Black_Bullet]

Yep same with me. Because you're routing more exhaust gases through the turbine wheel instead of wastegating them.

Hmm, makes sense.

 

[Turbo Talon DL]

I've never heard of or experienced a turbo car which loses power due to lower backpressure which is the ENEMY of turbo engines. I spin tires so much more easily (not purposely ) with open 3" d-pipe. The change in my cup holders will rattle up almost a quarter inch though. It is loud and obnoxious, it smells horrible because its not going through the cat, and boost is harder to control. Overall its kind of fun to do every now and then. I'd like to do a Seafoam job with the cutout open.

 

[JusMX141]

I've never heard of or experienced a turbo car which loses power due to lower backpressure which is the ENEMY of turbo engines.

I'm not talking about while being on boost; I'm strictly talking about off-boost torque, when your car is basically a non-turbo.

The bigger your turbo is, the more you'll notice a loss of off-boost torque as your powerband is moved higher into the RPM range. Someone running an open downpipe on a T25 would think it's great because the turbo spools just above idle anyway.