https://www.speed-engineering.com/s...-7-8-headers-y-pipe-2006-09-6-0l-engines.html
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Best inexpensive headers?
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https://www.speed-engineering.com/s...-7-8-headers-y-pipe-2006-09-6-0l-engines.html
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https://www.speed-engineering.com/s...9-trailblazer-ss/exhaust/headers-y-pipes.html
website says the expected arrival time isn't until 1/20, if you can wait a few weeks, this is the way to go
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and then this will increase that final y-pipe termination from 3" to 4"
https://www.jegs.com/i/Flowmaster/389/Y300400/10002/-1
https://www.jegs.com/i/Flowmaster/389/Y300400/10002/-1
I have had these on for 3yrs now and still like them. FYI i bought them when they had a sale for $550 to my door so it was an easy answer compared to over 2k for the better brands. Here in NJ we have emissions testing and i wanted a set with cats.
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In California, I'm supposed to have cats, right?
Reviving an old thread, can anyone verify a place to buy Speed Engineering headers?
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You can buy headers and y-pipe or just headers. I highly recommend their headers but I detest their y-pipe just as much as all the aftermarket single 3" cat-backs. Oddly Speed Engineering makes 2 different true-dual 3" exhausts for the Silverado, one of which I think will bolt right up to our TBSS but haven't verified yet. Just go bigger than a single 3" whatever you do.. no sense in putting on headers to clog the rest of the exhaust up. Good luck!
Thanks for the info! Are you saying their y-pipe isn’t worth buying? If not, is there an aftermarket one that fits up to those headers? Ideally I’d like to go with a true dual setup. That being said, could an exhaust shop work off of those headers and create the rest, or should they start from the end of the y-pipe?
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It's not just speed-engineering's y-pipe, its all the manufacturer's y-pipes for us. 3-issues..
one being that they merge to a single 3"; 2-3" pipes merging into a single 3" just makes no sense..
2nd issue being that it creates an imbalance (read power suck) between the driver's side and pass side engine banks bc drivers side becomes 3 feet longer before it can merge with other side, this negates any benefit of potential exhaust scavenging by merging both banks as soon as possible after the headers.
3rd issue is that the longer driver's side pipe runs directly under the transmission.. we have enough problems keeping our 4L70's cooled down, the last thing we need is a hot exhaust pipe radiating intense heat above to our trans.
one being that they merge to a single 3"; 2-3" pipes merging into a single 3" just makes no sense..
2nd issue being that it creates an imbalance (read power suck) between the driver's side and pass side engine banks bc drivers side becomes 3 feet longer before it can merge with other side, this negates any benefit of potential exhaust scavenging by merging both banks as soon as possible after the headers.
3rd issue is that the longer driver's side pipe runs directly under the transmission.. we have enough problems keeping our 4L70's cooled down, the last thing we need is a hot exhaust pipe radiating intense heat above to our trans.
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Part of the problem is with the exhaust routing being off center in the vehicle, ideal set-up would be similar to corvette routing.. all pipes being equidistant and x-pipe merge right after the headers.
The farther back in the vehicle that both banks are merged for exhaust scavenging reasons alone is the less performance benefit (if any) that will be produced.
Another reason to merge both engine banks is for noise-canceling and sound. Merging both banks results in a 2 decibel reduction on straight (no muffler) exhaust, less than 1 decibel reduction when combined with mufflers. It also changes the sound.. most people saying it sounds more "exotic" and less "hot-rodesque"
The farther back in the vehicle that both banks are merged for exhaust scavenging reasons alone is the less performance benefit (if any) that will be produced.
Another reason to merge both engine banks is for noise-canceling and sound. Merging both banks results in a 2 decibel reduction on straight (no muffler) exhaust, less than 1 decibel reduction when combined with mufflers. It also changes the sound.. most people saying it sounds more "exotic" and less "hot-rodesque"
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Another point to consider is the cross-sectional area in all the pipes and their relation to potentially lessening weight.
These figures are based on a full-length exhaust exiting the rear-most aspect of vehicle. Shorter exhausts (rear-axle dump) will be much more forgiving to these given hp limits.
2.5" pipe is 4.43 sq inches of cross sectional area
3" pipe is 6.49 sq in (not adequate for 400hp)
dual 2.5" is 8.86 sq in (stock 400hp C5 z06 size)
3.5" pipe is 8.95 sq in (lighter 400 hp alternative)
4" pipe is 11.79 sq in (optimal for up to 550hp)
dual 3" pipe is 12.98 sq in (optimal for up to 625hp)
4.5" pipe is 15.03 sq in (optimal for up to 700 hp)
dual 3.5" pipe is 17.90 sq in (optimal for up to 900hp)
5" pipe will be 18.67 sq in (optimal for up to 950hp)
dual 4" pipe will be 23.58 sq in (optimal for up to 1250hp)
Example- Factoring in the total circumference of dual-2.5" pipe vs a single 3.5", we have 15.71" and 11" respectively. This means that the total weight of dual 2.5" will be 43% heavier than a single 3.5", but both will support an equal amount of power.
These figures are based on a full-length exhaust exiting the rear-most aspect of vehicle. Shorter exhausts (rear-axle dump) will be much more forgiving to these given hp limits.
2.5" pipe is 4.43 sq inches of cross sectional area
3" pipe is 6.49 sq in (not adequate for 400hp)
dual 2.5" is 8.86 sq in (stock 400hp C5 z06 size)
3.5" pipe is 8.95 sq in (lighter 400 hp alternative)
4" pipe is 11.79 sq in (optimal for up to 550hp)
dual 3" pipe is 12.98 sq in (optimal for up to 625hp)
4.5" pipe is 15.03 sq in (optimal for up to 700 hp)
dual 3.5" pipe is 17.90 sq in (optimal for up to 900hp)
5" pipe will be 18.67 sq in (optimal for up to 950hp)
dual 4" pipe will be 23.58 sq in (optimal for up to 1250hp)
Example- Factoring in the total circumference of dual-2.5" pipe vs a single 3.5", we have 15.71" and 11" respectively. This means that the total weight of dual 2.5" will be 43% heavier than a single 3.5", but both will support an equal amount of power.
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Of note- all of gm's gas hd trucks, starting with the 360hp 6.0L, terminated in a 3.5" pipe. The factory tbss over-the-axle pipe necks down to as little as 2-1/4". Assumedly to maximize profits, GM used the same middle-to-rear exhaust pipe for all 3 engines used on this platform. This exhaust size wasn't even adequate for the 4.2L sixer; it's just god-awful restrictive for the 5.3 and LS2.
And people actually wonder why the corvette LS2 made 430hp, yet the tbss (with much better intake manifold) struggled to squeeze out 400....
And people actually wonder why the corvette LS2 made 430hp, yet the tbss (with much better intake manifold) struggled to squeeze out 400....
Wow, lots of great info! All good things to consider. I had considered making a custom dual 3” exhaust, using the y-pipe as the sacrificial piece to get things started.
How beneficial is wrapping the headers? I had considered this from the start to help keep temps lower under the hood and near the tranny, but I wasn’t sure how much tighter the clearance would be on the spark plug wires.
How beneficial is wrapping the headers? I had considered this from the start to help keep temps lower under the hood and near the tranny, but I wasn’t sure how much tighter the clearance would be on the spark plug wires.
Can you still get the headers at a discount? Thanks, Mike
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