Calling Doug Thorley Headers V8 Guys

[0verland]

This has been bugging me since I've installed my DT headers and I just have to know now. Is it normal to have a wispy air noise under load? There is no sign of the noise at idle but whenever you give it gas you can hear it. I asked the exhaust shop when I first picked it up and he even took at back on the lift again and double checked for leaks with me there watching but nothing. I trust them 100% as they have done all my vehicles and other family/friends. I just really can't wrap my head around this.

My only thought is that it might be that I used the OEM manifold gaskets (per Doug Thorley they are fine to run) or I am also running the Rutech Toyota 4.7L air induction pump bypass kit & exhaust port block-off plates. Could either of these have something to do with the noise? Anyone have any experience with this on the stock manifold or DT's?

Any insight would be great. I just need to put this to rest otherwise I'll be driven insane that something is wrong. Is this normal with these headers?

 

[RaceTRaCk]

It is. The factory manifolds are cast iron with very short runners absorbing the noise. I don't have DT's on my V8 but I had the DT long tube headers on my 2nd gen Taco and it was very noticeable which didn't really bother me.

 

[blackoutt]

DUDE! I feel like I've been the only one saying this since installing them, I also did not weld cats to them and just have straight 2.5" downpipes so I'm sure that doesn't help without dampening any sound. For the life of me I cannot find a leak anywhere around the header or welds to the downpipes
but they sound like leaky airflow pulses, maybe more so on the drivers side. I've sealed off my tailpipe and pressurized my exhaust spraying with soapy water and only found and fixed small gasket leaks further downstream. Headers seem fine but for sure sound "airy" when I don't want to hear them at all except for sweet sounds out of the tailpipe.

 

[0verland]

they sound like leaky airflow pulses, maybe more so on the drivers side.

Exactly how I would describe it. I can't figure it out either. Are you running the Rutech AIP kit and plates too? That truly is the only thing I can think of that would possibly be causing the sound since the air induction tubes are being blocked, but I'm not sure now much pressure those make or enough to make the pulsing airflow sound.

 

[blackoutt]

Exactly how I would describe it. I can't figure it out either. Are you running the Rutech AIP kit and plates too? That truly is the only thing I can think of that would possibly be causing the sound since the air induction tubes are being blocked, but I'm not sure now much pressure those make or enough to make the pulsing airflow sound.

Slyfox bypass and block off plates but yes that's the only other thing I can think of is that at idle I can't find a leak at those block off plates but under load they leak. If I had another vehicle I'd pull the headers back off and have the AIP tube welded shut at the end.

Also the pulse rate sounds more like EVERY exhaust pulse, not just one leaky primary (think 5.4 ford header tap). So it's gotta be on that common AIP rail! Or just the sound of every exhaust pulse in a tubular header.

 

[0verland]

Slyfox bypass and block off plates but yes that's the only other thing I can think of is that at idle I can't find a leak at those block off plates but under load they leak. If I had another vehicle I'd pull the headers back off and have the AIP tube welded shut at the end.

Also the pulse rate sounds more like EVERY exhaust pulse, not just one leaky primary (think 5.4 ford header tap). So it's gotta be on that common AIP rail! Or just the sound of every exhaust pulse in a tubular header.

You think the plates are leaking? Hmm thats a thought.... I took a look at them when I first got the kit and it seems to be quality and Rutech claims on their website that they are made from 304 stainless steel. I just can't imagine that there is that there is enough pressure to cause any leaking but again I don't know the ins and outs of the AIP system and whats entailed.

It is definitely on every pulse for sure though. The blockoffs seem to be the common thread in the scenario though. I have checked out quite a few videos on YouTube of Kevin Billmann who has the DT headers as well and in every video I have seen of his that you can get clear audio both inside the cabin and out there seems to be no sign of the pulsing air. I cannot confirm whether he has the block off plates or not though. Kevin if your a member and can chime in... anytime would be great. :bigok:

Any how this is still puzzling me but its good to know I'm not the only one. It seems though it might be isolated down to the the AIP block off plates. Would still like to hear from others and I will be doing more research into this myself.

 

[blackoutt]

I just asked Kevin if he's running AIP block off plates. We've chatted a little on instagram so hopefully he gets back to me. His does sound nice. Although in videos mine sounds really good too but to me I'm still irked when I drive next to another car or barrier.

 

[blackoutt]

Kevin says he is not running block off plates. DT headers with high flow cats welded to them. They were smooth and quiet when new but have since developed a leak somewhere.

Mine have been airy since day 1 a couple years ago and haven't changed.

 

[0verland]

Kevin says he is not running block off plates. DT headers with high flow cats welded to them. They were smooth and quiet when new but have since developed a leak somewhere.

Mine have been airy since day 1 a couple years ago and haven't changed.

I'm nearly convinced that its the block off plates that are causing the pulsing air sound. I wonder if welding them is the only fix?

 

[blackoutt]

I'm going to order some new gaskets and take the plates out to see what it sounds like. I guess no harm with the bypass module still in place? Just seems right to block the port not in use.

From Hewitt Tech:

11) Can I install the bypass module without the block-off plates?

This is a really common question mostly because the plate installation can seem a little daunting but the block off plates are an integral part of the solution. Many times the problem is just the air In cases where the actual air switching valves are physically stuck open or leaking the block-off plates are 100% required. In other instances where the problem is just a failing air pump causing the problems they are not as immediately required but the best practice is to always install them at the same time as the bypass module. This is because even though the system is not running anymore the air switching valves have been known to leak further down the road and put you into limp mode. The only way to completely isolate the system from the exhaust and ensure that the system is not a problem again is to install the block off plates. Just install them and don't worry about it again. If you don't make sure you put them in your glove box so you know where they are if and when you need them.

 

[coleb10]

Thanks for this thread. I am planning on installing the DT headers in the near future.

 

[meltdowner]

My DT headers will be here Friday and installed in the next couple weeks. I will let you know if I hear it ASAP.

 

[SAC-CA-Runner]

I think I have this problem, but it doesn't bother me. I am running the Rutech with the plates as well. I thought it was more my injectors just being loud or shitty CA gas pinging. I also have high flow cats welded on to the headers.

 

[0verland]

I'm going to order some new gaskets and take the plates out to see what it sounds like. I guess no harm with the bypass module still in place? Just seems right to block the port not in use.

From Hewitt Tech:

11) Can I install the bypass module without the block-off plates?

This is a really common question mostly because the plate installation can seem a little daunting but the block off plates are an integral part of the solution. Many times the problem is just the air In cases where the actual air switching valves are physically stuck open or leaking the block-off plates are 100% required. In other instances where the problem is just a failing air pump causing the problems they are not as immediately required but the best practice is to always install them at the same time as the bypass module. This is because even though the system is not running anymore the air switching valves have been known to leak further down the road and put you into limp mode. The only way to completely isolate the system from the exhaust and ensure that the system is not a problem again is to install the block off plates. Just install them and don't worry about it again. If you don't make sure you put them in your glove box so you know where they are if and when you need them.

Per Rutech's website

Block-Off Plates (2 included) - made from 304 Stainless Steel, prevents exhaust gasses from leaking back into the AIP valves. For codes P1441, P1444, P2440, P2442, you ‘must’ install the exhaust block-off plates. We highly recommend installation of the block-off plates in all circumstances, but for these 4 codes, the module and the plates are required to prevent these codes.


Running them without is fine and only needed with these four codes. I just threw them in there for preventative measure but I may take them out as well to see if everything runs fine. I truly can't stand the pulsing.

 

[DZNUTS]

I don’t have any kind of ‘pulsing’ noises from my DT headers with factory cats welded on, I do not have any block off plates installed.

I can tell you this much, after that install, those headers are not coming off ever again with the engine still in the truck!!


Sent from my iPhone using Tapatalk

 

[VertigoPerformance]

I bought these headers and planned to install this year when the engine was rebuilt, (it acquired a leaky valve stem seal a couple of years back)
Major front end work sidelined the project until next year now and I'm glad because it would be nice to have the issue resolved beforehand.

Has anyone called DT and asked exactly what the issue is and how to resolve it?

 

[blackoutt]

This has been bugging me since I've installed my DT headers and I just have to know now. Is it normal to have a wispy air noise under load? There is no sign of the noise at idle but whenever you give it gas you can hear it. I asked the exhaust shop when I first picked it up and he even took at back on the lift again and double checked for leaks with me there watching but nothing. I trust them 100% as they have done all my vehicles and other family/friends. I just really can't wrap my head around this.

My only thought is that it might be that I used the OEM manifold gaskets (per Doug Thorley they are fine to run) or I am also running the Rutech Toyota 4.7L air induction pump bypass kit & exhaust port block-off plates. Could either of these have something to do with the noise? Anyone have any experience with this on the stock manifold or DT's?

Any insight would be great. I just need to put this to rest otherwise I'll be driven insane that something is wrong. Is this normal with these headers?

Also what cats/downpipes do you have installed? The stock cats may help keep it quiet?

Mine sounds awesome in videos and can't hear the pftt-ing. Even riding passenger seat where the exhaust comes out the right side it sounds good, but paranoid driver still hears the sound!

 

[0verland]

I bought these headers and planned to install this year when the engine was rebuilt, (it acquired a leaky valve stem seal a couple of years back)
Major front end work sidelined the project until next year now and I'm glad because it would be nice to have the issue resolved beforehand.

Has anyone called DT and asked exactly what the issue is and how to resolve it?

I don't believe it to be a header flaw but more of the block-off plates. Seems they aren't sealing correctly. Keep in mind the block off plates are only relevant to 05-09 as the 03-04 have no air injection. I wouldn't hesitate to install yours... They are a massive upgrade.

Also what cats/downpipes do you have installed? The stock cats may help keep it quiet?

Mine sounds awesome in videos and can't hear the pftt-ing. Even riding passenger seat where the exhaust comes out the right side it sounds good, but paranoid driver still hears the sound!

I took out the stock cats and replaced them with Flowmaster HFCs. They are the universal 3" handspun design.

I still have the stock Y-pipe installed. I can't bring myself to spend $400+ on the URD Y-pipe.

 

[meltdowner]

You guys ever get to the bottom of this? Is it looking like the block off plates?

 

[Inv4drZm]

....Running them without is fine and only needed with these four codes. I just threw them in there for preventative measure but I may take them out as well to see if everything runs fine. I truly can't stand the pulsing.....

I'm going to order some new gaskets and take the plates out to see what it sounds like. I guess no harm with the bypass module still in place? Just seems right to block the port not in use.

[MENTION=117708]blackoutt[/MENTION] [MENTION=169058]0verland[/MENTION] did you guys ever try this?

I don't have/need the blockoff plates just curious, I've got a tig welder and I want to use it for something LOL, though I probably don't need to in this instance.