Limitations of 3" Downpipe?
Launching!
Joined: Jun 2006
Posts: 209
Likes: 2
From: Middle of MI
What kind of build you doing? Depending on where you're at in MI, there's gotta be someone who you could peek at their car.
I'd agree with NicD that for under 600whp, you shouldn't have a problem running the WG pipe to where you can go to 3.5". I'm guessing this isn't an all out build? Thus the reason for a bit of civility with the WG? A cut out somewhere in there could get you some more hp if you really needed it.
I'd agree with NicD that for under 600whp, you shouldn't have a problem running the WG pipe to where you can go to 3.5". I'm guessing this isn't an all out build? Thus the reason for a bit of civility with the WG? A cut out somewhere in there could get you some more hp if you really needed it.
On The Tree
Joined: Aug 2013
Posts: 174
Likes: 0
From: Lake Stevens, WA
why are you so determined for a recerc wastegate? yes they do seem to quite it down some. in fact the last one i built for myself was open and noticeably loud, but given the car and the fact your WOT making a pull really makes it a mood point. not like your creeping past the law WOT 80+ mph are you? lol
Im making 600whp with full 3" exhaust and recirculating my wg. I just like it for being quiet for the sleeper affect. I have an electric cutout after my cat for when a little more muscle is needed.
TECH Regular
Joined: Oct 2014
Posts: 415
Likes: 2
To answer the original question, I think John from LJMS hit the nail on the head about the point in which it becomes a restriction.
Unfortunately in these 4th gen F-bodies as some have pointed out, room becomes the restriction as to how big you can go, and your choice of how you want your exhaust to go determines the rest.
I am shooting for 1,000 at the tire in my F-body. 3" downpipe would not get me there. I am hoping that my 4" downpipe into a dump under the car will get the job done, but the car is easily a month, if not two before it will be ready to find out. Finding room for the 4" downpipe has been a big problem with clearance. I am getting it done, but there has been a lot of custom fabrication and time involved with getting it done (hence why my car is also still on jackstands, and not running yet).
Good luck with your build.
Unfortunately in these 4th gen F-bodies as some have pointed out, room becomes the restriction as to how big you can go, and your choice of how you want your exhaust to go determines the rest.
I am shooting for 1,000 at the tire in my F-body. 3" downpipe would not get me there. I am hoping that my 4" downpipe into a dump under the car will get the job done, but the car is easily a month, if not two before it will be ready to find out. Finding room for the 4" downpipe has been a big problem with clearance. I am getting it done, but there has been a lot of custom fabrication and time involved with getting it done (hence why my car is also still on jackstands, and not running yet).
Good luck with your build.
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I like recirculation. I've always been worried if anything goes whack. The wg will blow fireballs in the engine bay. If its vented to atmo.
I've never seen it happen. But I've heard about it. I like the quiet sound. That's why I'm putting a CAI on my turbos. To quiet em down but still breathe better than with a just a filter over the compressor. Quieter. And breathe colder air.
I've never seen it happen. But I've heard about it. I like the quiet sound. That's why I'm putting a CAI on my turbos. To quiet em down but still breathe better than with a just a filter over the compressor. Quieter. And breathe colder air.
if your wastegate is set up to flow good (primary angle) and you dump it back in at a good angle not 90* to the flow it will not cause you any issue. I run mine back in at a 45* angle and it works perfect. last turbo was a 3.5 dp going to a homemade 3"
y pipe and dual 3" flowmasters and tailpipes out the back . still doing the same with my 4" down pipe and s480 turbo and the same exaust system . I thought id get some boost creep with my 38 mm gate and exaust backpressure but it still holds 10# steady. didn't like the screamer pipe at all.
y pipe and dual 3" flowmasters and tailpipes out the back . still doing the same with my 4" down pipe and s480 turbo and the same exaust system . I thought id get some boost creep with my 38 mm gate and exaust backpressure but it still holds 10# steady. didn't like the screamer pipe at all.
Thing is though, WOT is so loud anyway I cant see how the screamer pipes make any difference. I run Magnaflows which are quiet normally but at WOT those suckers are still loud so the screamers are really irrelevant at that point IMO.
Now, sitting there on a 2 step - yeah, you'll notice the screamers.
Now, sitting there on a 2 step - yeah, you'll notice the screamers.
Thread Starter
TECH Resident
Joined: Oct 2009
Posts: 793
Likes: 0
From: Michigan
The sound varies on different setups, but some people just don't care for the completely unmuffled dump pipes blasting away. It's a personal preference thing.
69-chvl, I'm curious if you've ever experienced a car with a recirculated WG? I have, and I don't want my next setup to NOT have one!
Another little interesting tidbit I've noticed along the way is that some people end up with better boost control when they are recirculating than when their dump tube is open to the atmosphere. I'm not sure if it's because of the added resistance in the down pipe diminishing the flow through the turbine a tiny bit in favor of the wastegate, or if it's because of the bernoulli effect pulling the flow through the wastegate dump tube (or maybe both).
69-chvl, I'm curious if you've ever experienced a car with a recirculated WG? I have, and I don't want my next setup to NOT have one!
Another little interesting tidbit I've noticed along the way is that some people end up with better boost control when they are recirculating than when their dump tube is open to the atmosphere. I'm not sure if it's because of the added resistance in the down pipe diminishing the flow through the turbine a tiny bit in favor of the wastegate, or if it's because of the bernoulli effect pulling the flow through the wastegate dump tube (or maybe both).
my car has a nice rumble at idle but at rpm in boost I can hear the engine in the car but outside all you hear is the sound of the turbo whistle. I love it.
my screamer pipe was three times louder than the exaust exiting behind the rear wheels. before I added the intercooler I got a little aggressive on the tune and I could hear it spark knock plain as day. I dropped the timing down 2 degrees and it was quiet again. I love it quiet.
my screamer pipe was three times louder than the exaust exiting behind the rear wheels. before I added the intercooler I got a little aggressive on the tune and I could hear it spark knock plain as day. I dropped the timing down 2 degrees and it was quiet again. I love it quiet.
