PLM Long Tube Header

[Hyper4mance2k]

Originally Posted by Lithium

So, I finally installed my PLM header, over-pipe, and mid-pipe for the second time. I didn't want to blow up the forums when I noticed that the over-pipe inlet (2.5 inch) didn't fit the Header outlet (3 inch).
Below is the exhaust manifold outlet at 2.8 inches ID

Next is the over-pipe inlet at 2.3 inches ID

That's a ridiculous amount of material to just "overhang" into the exhaust path. As you can see form this picture its a huge restriction. Take note of how little of that flange is actually compressing the exhaust gasket, its a few Millimeters
So after a night of thinking about how terrible this exhaust was designed I decided I wasn't going to just let it sit like that. I decided to take it apart again and weld on larger portions of 1/4inch plate steel to increase the surface area of the flange. This would allow for a much better seal against the exhaust gasket and it would also give me room to port out the inside of the over-pipe flange. This still isn't the ideal way to mate a 3inch pipe to a 2.5 inch pipe but with such little space its the easiest to do without completely modifying the header itself.

Here is a picture of what it looked like afterwards, not pretty but it will at least help me sleep at night.

1) Why not just buy a 3" over pipe to match your 3" outlet header. I'm not so good at math, but 2.5"<3"...

2) Drone & Rasp are a component of header & exhaust wall thickness, and your exhaust's ability to cancel out high frequency waves. Cats eliminate drone, and proper resonators eliminate drone. The header is cheap thin wall. Without good resonators any header, especially a thin wall header will drone & rasp like mad. Your Topspeed, eBay, thin wall, poor resonated exhaust is the last thing in the world that I would expect to correctly manage drone.

3) You get what you pay for. Would I buy this header if I didn't already have one, yes. Would I expect it to perform the same as a header & exhaust 3-4 times the price, no.

[2016 Camaro SS]

Originally Posted by Hyper4mance2k

1) Why not just buy a 3" over pipe to match your 3" outlet header. I'm not so good at math, but 2.5"<3"...

2) Drone & Rasp are a component of header & exhaust wall thickness, and your exhaust's ability to cancel out high frequency waves. Cats eliminate drone, and proper resonators eliminate drone. The header is cheap thin wall. Without good resonators any header, especially a thin wall header will drone & rasp like mad. Your Topspeed eBay exhaust is the last thing in the world that I would expect to correctly manage drone.

3) You get what you pay for.

Most 3" overpipes don't fit well and rub. A lot of the overpipes are 2.5" then size up to 3" to mate with the 3" front pipe.

I figured this was going to be difficult for the Nameless header when they announced the 3" flange to go with their 3" DP/OP making it more difficult to use other offerings.

[KoolBRZ]

Originally Posted by Hyper4mance2k

1) Why not just buy a 3" over pipe to match your 3" outlet header. I'm not so good at math, but 2.5"<3"...

2) Drone & Rasp are a component of header & exhaust wall thickness, and your exhaust's ability to cancel out high frequency waves. Cats eliminate drone, and proper resonators eliminate drone. The header is cheap thin wall. Without good resonators any header, especially a thin wall header will drone & rasp like mad. Your Topspeed, eBay, thin wall, poor resonated exhaust is the last thing in the world that I would expect to correctly manage drone.

3) You get what you pay for. Would I buy this header if I didn't already have one, yes. Would I expect it to perform the same as a header & exhaust 3-4 times the price, no.

Drone is caused by rubbing and/or the tune. If yours isn't rubbing, then your tune needs the AVCS backed off some. Mine droned at 3000 RPM's bad with the tune I was using over the weekend, and had an annoying flat spot, but with the tune I loaded yesterday with the AVCS backed off to the way Shiv wrote it, (OFT 2.06, stage 2, 91 Oct. UEL) I'm not getting any drone. See video.
[ame]http://youtu.be/Qcz-XJCMOUU[/ame]

This is with a horribly restrictive 2.25" inlet - 2.5" outlet Ebay Topspeed Pro 1 overpipe, an Ebay Topspeed Pro 1 catless resonated front pipe, stock midpipe, and topspeed pro 1 axle-back dual exit muffler. My "Topspeed, eBay, thin wall, poor resonated exhaust" handles the drone just fine. Your either rubbing the frame, and/or your tune has too much AVCS overlap.

Not to start a flame war, but it's your tune, dude.

[churchx]

Someone should make oval shaped/flattened cross-section OP to fix that. After all, if aceheader managed to pass two pipes side by side in overpipe section for their header, there should be clearance to pass through for wider one, that will be both less restrictive AND have less rubbing/fitting issues vs one welded from round tubes.

[Turdinator]

Originally Posted by churchx

Someone should make oval shaped/flattened cross-section OP to fix that. After all, if aceheader managed to pass two pipes side by side in overpipe section for their header, there should be clearance to pass through for wider one, that will be both less restrictive AND have less rubbing/fitting issues vs one welded from round tubes.

I like that idea. I was also thinking one that tapers from 3" to 2.5" would be nice but then with a header as cheap as the PLM why not chop and weld it so the outlet is 2.5"?

[Hyper4mance2k]

Originally Posted by KoolBRZ

Drone is caused by rubbing and/or the tune.

Please don't ever correct me again. I wasn't addressing you. If I want to address you, I will call you out by name.
You have never been right when you have made something up to try and explain something you don't understand.
Your exhaust will quiet down if you mess with cam timing. If it gets quieter, you can obviously eliminate drone. If your car is tuned correctly, which yours obviously is not, then drone is caused by exhaust wall thickness and resonance not tuned out by the resonators, or adequate wall thickness exhaust components.
I have been building race cars longer than you have been alive.

[Cross]

Originally Posted by Hyper4mance2k

Please don't ever correct me again. You have never been right when you have made something up to try and explain something you don't understand.
Your exhaust will quiet down if you mess with can timing. If it gets quieter you, can obviously eliminate drone. If your car is tuned correctly, which yours obviously is not, then drone is caused by exhaust wall thickness and resonance not tuned out by the resonators, or adequate wall thickness exhaust components.
I have been building race cars longer than you have been alive.

I admit it I was laughing because of this

[Lithium]

Originally Posted by Hyper4mance2k

Please don't ever correct me again. I wadnt addressing you. If I want to address you, I will call you out by name.
You have never been right when you have made something up to try and explain something you don't understand.
Your exhaust will quiet down if you mess with can timing. If it gets quieter you, can obviously eliminate drone. If your car is tuned correctly, which yours obviously is not, then drone is caused by exhaust wall thickness and resonance not tuned out by the resonators, or adequate wall thickness exhaust components.
I have been building race cars longer than you have been alive.

I too find this funny however a lot of variable's come into play when it comes to exhaust noise. Blanketing all sound on wall thickness and "resonance" isn't completely accurate. In my experience thermal capacity and exhaust temps play much more of a role than either of the two or should I say one characteristic you have stated. (resonance is a constantly changing by-product)

[Andrew025]

Originally Posted by KoolBRZ

Drone is caused by rubbing and/or the tune. If yours isn't rubbing, then your tune needs the AVCS backed off some. Mine droned at 3000 RPM's bad with the tune I was using over the weekend, and had an annoying flat spot, but with the tune I loaded yesterday with the AVCS backed off to the way Shiv wrote it, (OFT 2.06, stage 2, 91 Oct. UEL) I'm not getting any drone. See video.

This is with a horribly restrictive 2.25" inlet - 2.5" outlet Ebay Topspeed Pro 1 overpipe, an Ebay Topspeed Pro 1 catless resonated front pipe, stock midpipe, and topspeed pro 1 axle-back dual exit muffler. My "Topspeed, eBay, thin wall, poor resonated exhaust" handles the drone just fine. Your either rubbing the frame, and/or your tune has too much AVCS overlap.

Not to start a flame war, but it's your tune, dude.

Yeah, the tune could (it does) have an affect on "drone", but you're addressing it the wrong way if you're editing the way the car runs to get rid of a noise that isn't an actual problem.

[Hyper4mance2k]

Originally Posted by Lithium

I too find this funny however a lot of variable's come into play when it comes to exhaust noise. Blanketing all sound on wall thickness and "resonance" isn't completely accurate. In my experience thermal capacity and exhaust temps play much more of a role than either of the two or should I say one characteristic you have stated. (resonance is a constantly changing by-product)

I'll give you that, but 90% of the time that's the issue. Thin wall exhaust pipes, or header pipes for that matter, will not eliminate resonant frequencies, and will themselves vibrate and add to the noise. I've spent the better part of the last 20 years building rotaries. I know all too well the pain of dealing with loud exhausts.

[KoolBRZ]

Originally Posted by Andrew025

Yeah, the tune could (it does) have an affect on "drone", but you're addressing it the wrong way if you're editing the way the car runs to get rid of a noise that isn't an actual problem.

I agree, but that wasn't why I was editing the tune. When it had the buzzing drone at 3000 RPM's it had a really frustrating flat spot from about 3500 - 4500 RPM's. I've been gradually adjusting my valve overlap with the AVCS tables in Rom Raider. I got it working pretty good with my old header, but the new long-tube header didn't run the same. It had more low-end torque, a buzzing drone at 3000 RPM's, and a really frustrating flat spot between 3500 and 4500 RPM's. I had a theory that the valve overlap I had lately been increasing, was too much for the new header. So, I copied the un-modified tables into my latest tune and loaded it up. Then I made another tune with the AVCS tables from Shiv's ESC tunes. Now I have 3 levels of AVCS tuning. The ESC tables are the mildest, then the stage 2 91 Oct. UEL is a bit hotter with more overlap, and finally my modified tune with my latest AVCS tables which is too much. Today I tried the tune with ESC tables, then the tune with the stage 2 91 Oct. UEL tables, and that one was the best so far. That's the tune used in the video.

And for those with YEARS of experience, if you think you know it all, then those years of experience haven't taught you a thing.

[KoolBRZ]

Update. Having tried tunes that were 2 points lower, and 4 points lower, I can say that I found that the flat spot is less noticeable with the intake safe table modded to reduce overlap. See pics below;

I started with a customized UEL tune, (top pic) to find out whether it was intake or exhaust that needed modification. That showed me that the intake table actually needed to be changed to compensate for an exhaust modification!? Crazy, right. Then, just to be sure I wasn't overlooking the possibilities of shiv's EL tune. I copied the intake safe table from that, (2nd pic) and compared that as well. Turns out it works pretty good. It seemed better, in fact, then the UEL tune, except for a dreadful flat spot. With what I learned previously from the mods to the UEL tune, I felt sure I could get rid of the flat spot and keep the other advantages of the EL tune. So, I modded the EL tunes' safe table in the same areas I'd modded the UEL tune, and that's pic 3. This is the best tune I have so far for the PLM long tube header.

[Hyper4mance2k]

Originally Posted by KoolBRZ

Update. Having tried tunes that were 2 points lower, and 4 points lower, I can say that I found that the flat spot is less noticeable with the intake safe table modded to reduce overlap. See pics below;

I started with a customized UEL tune, (top pic) to find out whether it was intake or exhaust that needed modification. That showed me that the intake table actually needed to be changed to compensate for an exhaust modification!? Crazy, right. Then, just to be sure I wasn't overlooking the possibilities of shiv's EL tune. I copied the intake safe table from that, (2nd pic) and compared that as well. Turns out it works pretty good. It seemed better, in fact, then the UEL tune, except for a dreadful flat spot. With what I learned previously from the mods to the UEL tune, I felt sure I could get rid of the flat spot and keep the other advantages of the EL tune. So, I modded the EL tunes' safe table in the same areas I'd modded the UEL tune, and that's pic 3. This is the best tune I have so far for the PLM long tube header.

You should really take the time to rent a dyno for a few hours so you can try out your mapping and actually get some quanitfiable data. Otherwise you're just pissing into the wind. You can use the dyno to do part throttle tunes as well. Since I know you've mentioned pulling your trailer with your BRZ, I'd guess part throttle and low RPM torque are priorities for you. You can build an adjustable throttle-stop under the pedal to get repeatable pulls. Diesel guys do this all the time.

[KoolBRZ]

Originally Posted by Hyper4mance2k

You should really take the time to rent a dyno for a few hours so you can try out your mapping and actually get some quanitfiable data. Otherwise you're just pissing into the wind. You can use the dyno to do part throttle tunes as well. Since I know you've mentioned pulling your trailer with your BRZ, I'd guess part throttle and low RPM torque are priorities for you. You can build an adjustable throttle-stop under the pedal to get repeatable pulls. Diesel guys do this all the time.

That's a good idea. Unfortunately, I don't have the time or money to dyno at this time. I can load multiple tunes on the OFT and switch back and forth between them to find out by driving which direction to make a change, and even how much to change. I had a 35 mile trip to Wilsonville, OR from Vancouver, WA and back today, so I loaded several similar tunes and drove, trying to decide which is better and why.

With shiv cutting the write time in half it isn't too inconvenient to switch tunes. With the knowledge gained from driving and switching between tunes today I wrote 2 changes to the best tune. Small changes a little bit higher and a little bit lower then they were in the best tune help me to decide where I can make changes and how much in which direction.

Having an automatic means it's not just about peak horsepower. Because I don't clutch, or even let off the throttle, between gears, the tune has to prevent hesitation after a shift. This is primarily to prevent annoying me, because after shift whiplash probably isn't harmful, but it is annoying. Smoothing out the power-band to eliminate as much of the flat spot as possible is also annoyance prevention, because the transmission loves to shift right between 3000 and 4000 RPMs in the absolute worst place possible.

I usually shift manually because I get more response in the lower gears, but when I'm in stop and go traffic, or driving my wife around I'll use automatic mode. My wife doesn't like me to drive scary, see youtube video.

[ame="https://www.youtube.com/watch?v=fX_sQt3i2IQ"]YouTube[/ame]

People drive really fast around here! Especially souped-up Prius owners.

I would like to work with like-minded people to tune out the flat spot, and I'm open-minded about other peoples input. Come on, it isn't rocket science.