Dual cat header options
#1
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Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Dual cat header options
A couple weeks ago one of my cats started rattling, wasn't a huge issue but now I think that it's intermittantly getting clogged. So that means I need some new cats, however if I'm going to mess with that I may as well get headers and a Y-pipe. I have the dual cats on my car and don't particularly want to convert to a single cat set-up for various reasons. One being that two 2.25. cats will outflow even a single 3". Another huge factor is that smaller diameter pipes/cats means more ground clearance, and I need all I can get, I'd better than stock exhaust clearance. I also need to stay with shorties and stock exhaust routing to stay legal in the STX class so that rules out long tubes for now. Unfortunately aftermarket support for dual cats is very limited. So far I've only come up with:
Edelbrock TES #68762
Hedman Hedders # 68491
Dyno Don's
Hooker 2056 (out of production)
SLP Tri-Y's ( out of production)
The SLP's and Hookers haven't been available since around 2005 so I wont consider those. You can count out the Edebrocks due to their horrendous collector design. I'd love to have Dyno Dons but they're a tad spendy for even the mild steel versions, and there is very,very little info on the Headmens, not even any pictures. I'd prefer to make my own Y-pipe but I don't have my own welder or access to one otherwise it would be done already.
Are there any other options out there? I guess I never really looked into the shorty header options for our cars much and even the "best" ones have pretty iffy collector designs.
Edelbrock TES #68762
Hedman Hedders # 68491
Dyno Don's
Hooker 2056 (out of production)
SLP Tri-Y's ( out of production)
The SLP's and Hookers haven't been available since around 2005 so I wont consider those. You can count out the Edebrocks due to their horrendous collector design. I'd love to have Dyno Dons but they're a tad spendy for even the mild steel versions, and there is very,very little info on the Headmens, not even any pictures. I'd prefer to make my own Y-pipe but I don't have my own welder or access to one otherwise it would be done already.
Are there any other options out there? I guess I never really looked into the shorty header options for our cars much and even the "best" ones have pretty iffy collector designs.
#2
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Car: '90 Trans Am-12.45@110.71
Engine: 355 w/AFR 195's Elem. 400/430 HP/TQ
Transmission: Tremec T-56
Axle/Gears: 12 Bolt 3.73
Re: Dual cat header options
It doesn't get any better than this:
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Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: Dual cat header options
Don, that sure looks good!!
#4
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Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Dual cat header options
Yup, I'm considering your headers. I just want to at least evaluate EVERY option out there. Don would you perhaps be able to make a set with a true merge collector instead of a formed collector, or a Tri-Y set up? That's my biggest gripe about shorties and that where the majority of horsepower is gained or lost.
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Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Dual cat header options
See something like those are what I wish were publicly available.
#7
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Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Dual cat header options
I ended up ordering a set from Dyno Don. I don't see how people think they're that expensive as the turn out to be cheaper than an equivalent set of hooker 2055's. Can't wait to get these on my door step.
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#8
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Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Dual cat header options
Look like my headers just arrived, I'm pleased with how they turned out. I'll be able to install them after the holidays. Here's some pictures I took.
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Car: '90 Trans Am-12.45@110.71
Engine: 355 w/AFR 195's Elem. 400/430 HP/TQ
Transmission: Tremec T-56
Axle/Gears: 12 Bolt 3.73
Re: Dual cat header options
Awesome pictures, with your permission I would like to save them to my collection.
#11
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Car: '91 Camaro Z28, '85 Camaro Z28
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Re: Dual cat header options
Of course, feel free to use them however you please.
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Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Dual cat header options
Well I figured I should update this as it is now 4 months later and I've finally got these installed. The install was fairly straightforward, thankfully I had no issues removing the old manifolds. Well, except for breaking my Hypertech fan switch. :duh:
I removed the AIR box and associated tubing and tucked away the wiring. I left the pump in there for now until I either get a delete pulley or figure out how to reroute the belt. It's nice to be able to see the passenger side valve cover for once! Eventually I want to relocate the diverter valve and coolant hose to an out-of-sight location to try and simplify the look even more.
The passenger side was a bit tricky to get in there. I ended up being able to slide it in from the top but I had to remove the spark plugs, dip stick tube, unbolt the little bracket that holds the coolant hard line to the frame rail so I could bend it out of the way, and I had to stress the A/C box just enough to slide the header in there.
The drivers side was much easier. After removing the manifold, I unbolted the steering shaft and rerouted the brake lines to the outside, as close the the strut tower as possible. The stock O2 sensor wire worked just fine, I just had to reroute that portion of the harness too and slthrough connector for the CTS through the gap between the motor mount and block, that way it can't come anywhere near the primary tubes. I also routed all my spark plug wires under the headers tight against the block and used some protection sleeves. I like the fact that they're hidden and out of the way.
As you can see I was able to retain the alternator brace. I simply used the stock manifold bolt and cut down a spacer to the right length. I will do the same for the A/C brace on the other side but it'll take some grinding on that brace as will interfere with the #4 primary.
Underneath I was able to tuck up the down pipes to gain better than stock ground clearance . I'm pretty excited about this because with my ride height I need all I can get. It was half the reason why I went with the dual cat down pipes rather than the single pipe. The other reason is because it will make it a lot easier for me to convert to true duals down the road. :wink: I also wrapped the down pipe where it crosses under the oil pan to try and reduce oil temperature.
I used Mr Gasket header bolts, and I really like them. They are both an Allen head and hex head all in one, which means I was able to fit an 11mm socket on all the accessible ones and a wrench or Allen socket on the rest.
For gaskets I used Percy's dead soft aluminum stackable gaskets. No review on those yet but they seem nice and I've only heard good things about them, plus they were pretty cheap in comparison to the competition. $30 off the shelf at my local Autozone.
Today I'm getting the 2-1 merge made and the Y-pipe welded up, so hopefully my exhaust will be done by the end of the night ::fingers crossed:: I'm getting sick of these open down pipes already.
I removed the AIR box and associated tubing and tucked away the wiring. I left the pump in there for now until I either get a delete pulley or figure out how to reroute the belt. It's nice to be able to see the passenger side valve cover for once! Eventually I want to relocate the diverter valve and coolant hose to an out-of-sight location to try and simplify the look even more.
The passenger side was a bit tricky to get in there. I ended up being able to slide it in from the top but I had to remove the spark plugs, dip stick tube, unbolt the little bracket that holds the coolant hard line to the frame rail so I could bend it out of the way, and I had to stress the A/C box just enough to slide the header in there.
The drivers side was much easier. After removing the manifold, I unbolted the steering shaft and rerouted the brake lines to the outside, as close the the strut tower as possible. The stock O2 sensor wire worked just fine, I just had to reroute that portion of the harness too and slthrough connector for the CTS through the gap between the motor mount and block, that way it can't come anywhere near the primary tubes. I also routed all my spark plug wires under the headers tight against the block and used some protection sleeves. I like the fact that they're hidden and out of the way.
As you can see I was able to retain the alternator brace. I simply used the stock manifold bolt and cut down a spacer to the right length. I will do the same for the A/C brace on the other side but it'll take some grinding on that brace as will interfere with the #4 primary.
Underneath I was able to tuck up the down pipes to gain better than stock ground clearance . I'm pretty excited about this because with my ride height I need all I can get. It was half the reason why I went with the dual cat down pipes rather than the single pipe. The other reason is because it will make it a lot easier for me to convert to true duals down the road. :wink: I also wrapped the down pipe where it crosses under the oil pan to try and reduce oil temperature.
I used Mr Gasket header bolts, and I really like them. They are both an Allen head and hex head all in one, which means I was able to fit an 11mm socket on all the accessible ones and a wrench or Allen socket on the rest.
For gaskets I used Percy's dead soft aluminum stackable gaskets. No review on those yet but they seem nice and I've only heard good things about them, plus they were pretty cheap in comparison to the competition. $30 off the shelf at my local Autozone.
Today I'm getting the 2-1 merge made and the Y-pipe welded up, so hopefully my exhaust will be done by the end of the night ::fingers crossed:: I'm getting sick of these open down pipes already.
Last edited by DBLTKE; 04-18-2012 at 10:18 AM.
#13
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Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Dual cat header options
Almost finished! It was a lot of work with plenty of cutting and rewelding yesterday. We had to call it a night before we were 100% done. All we have left to do is actually put the final welds on the pipes but the piping is all fitted and hanging correctly. I'm very pleased with the merge that this guy made. I just might come back to him with a few more projects. Here's a teaser.
Just to clarify I am running a single 3" for now with an SLP loudmouth 2 cat back. I imagine that in a year or so I will switch to true duals. today we're going to finish up the rest of the welds and fab up a hanger to use in the stock location by the transmission. Stay tuned.
Just to clarify I am running a single 3" for now with an SLP loudmouth 2 cat back. I imagine that in a year or so I will switch to true duals. today we're going to finish up the rest of the welds and fab up a hanger to use in the stock location by the transmission. Stay tuned.
Last edited by DBLTKE; 04-18-2012 at 10:09 AM.
#14
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Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Dual cat header options
Clearance is pretty tight around the front right corner of the subframe by the RF tire, the pipe has about .75" of clearance to the subframe, but there is no contact and no rattling/vibration. There's still plenty of space above the pipes to the floor. Enough room to have SFC's, yet they still tuck up higher than the subframe. The lowest part of my exhaust is now my muffler in front of the axle.
#15
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Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Dual cat header options
The ground clearance is awesome you can barely even see the pipes under the car
#17
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Re: Dual cat header options
DBLTKE -
Great photos and great thread. I ordered a set of Dyno Don's headers as well and they will be arriving tomorrow. Manifolds are off and I'm looking to install by this weekend. What plugs and plug wires did you end up using?
Your car looks great.
Great photos and great thread. I ordered a set of Dyno Don's headers as well and they will be arriving tomorrow. Manifolds are off and I'm looking to install by this weekend. What plugs and plug wires did you end up using?
Your car looks great.
#18
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Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
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Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Dual cat header options
I run NGK plugs, one step colder than stock and Taylor cut-to-fit plug wires with all 90* ends.
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Car: 1989 GTA
Engine: L98
Transmission: WC T5
Axle/Gears: 3.45
Re: Dual cat header options
Bringing up an older thread, Are you using Dyno Don's on a T5 tranny or the 700r4? I want to clear my slave cylinder on my T5. Thank you.
#20
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Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: Dual cat header options
As you can see in the pix above, the pipes run on the pass side of the car and the slave is on the driverside of the trans tunnel. No issues.
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