I've been putting a lot of thought into re-doing my exhaust. currently my car has:

Flowtech headers, 1.5" primary, 2.5" collector, 2.5" pipe.
3" Arvin catalytic converter
2.75" GM intermediate pipe
Flowtech Afterburner muffler (3" in, 2.5" outs)


I allready bought new headers, hook 2460 - ceramic coated. So heres what I'm thinking of putting together at the end of this
month:

Hooker 2460 headers, 1 5/8 primary, 3" collector
Dual 2.5" mandrel bent (custom) pipes from collectors
Y-pipe - 2.5" to 3" (flowmaster?)
3" Intermediate pipe, prolly dynomax, hooker, or slp
Keep the muffler, put the flowmaster back on, or hooker, or
slp?

As you can see I'm not sure what parts to use for some of the connections. I was thinking of using some custom 90" bends, and
pipes for the headers to a y-pipe adapter.

As far as the y-pipe adapter, I was thinking either a flowmaster,
or maybe even a cutout ?

After that, I'm thinking a catsound cat - but a shorter one to compensate for the y-pipe.

Cat-back I have no clue. I could get dynomax i-pipe, hooker catbck, or an slp for a 4th gen.

-- Joe

 

From Summit:
Catco direct-fit high-flow cat CTO-9118, $117. Hooker catback HOK-16823, $265. Flowmaster Y, FLO-Y250300A, $38.

Install them, have the downpipes fabricated to meet the Y inlets.

You could have gotten Hooker 2055 from Jet Hot for $570 shipped (headers & y-pipe ceramic coated inside & out). All mandrel bent, no fabrication would have been required at all.

 

I paid $261.00 shipped for the 2460's coated inside and out, and
the 2460 is better header. Thicker, larger collector, longer collector. Thats why I went that route.


What do you think of dynomax cat back? there is a local guy selling one for $100.00 (new)??

The only problem I see with CTO-9118 is its direct fit.. 1) its longer than I think I want, and 2) the ball flange would cut down on the pipe size, much like the 2055's do.

-- Joe

 

Some ideas..

 

..

 

You said that in another post. Can you back up the "thicker" part? I haven't seen anything on the Holley/Hooker website that says that.

I've gotten more comfortable with Dynomax in general in the last year or so. I'm considering some of their quieter mufflers for the '57 this winter (their Bullets are great for performance, not so great when you see Smokey in the rearview).

I've stated in several posts what to do about the 2055 ball flange. When you do that, there is no significant difference between the 2460 collector flow and 2055 collector flow. You can do the same thing to the direct fit cat if needed (I haven't seen one, so I haven't measured to know for certain that it's needed).

The length would be solved in your last view (which is roughly what the 2055 y-pipe looks like).

 

Yeah sorry, figured you'd just take my word for it.

2460 is a "Competition header" which is outlined in this description on Hookers website:

http://www.holley.com/HiOctn/ProdLin...HHCH/Comp.html

2055 is a "Super Competition header", which is outlined here:

http://www.holley.com/HiOctn/ProdLin.../ESHHinfo.html

I've called and talked to Chris at Hooker and he verrified. Comp headers have a slightly longer collector, and are 16 gauge instead of 18 gauge. Super Comp's are more expensive because they are "exact fit" headers for a vehicle, and are CARB approved.


You can goto the actual header pages and look at the specs on each one to verify the collector length i'm referring to.

Watch it, I may take offense to that.

I understand that, and agree with you on the OEM style collector. But I still don't want it on my cat.. 3" is small enough.

Plus, I think the direct-fit cat is gonna be a 2 3/4 on the flange side to begin with, and then the ball will restrict it even furthur. makes the whole 3" i-pipe a useless purchase. We don't need to slow the pressure down coming from the kitty.


Keep in mind, I'm not saying 2055's are junk.. I'm saying I think 2460's with the right y-pipe will outflow them, for less money. Thats all. I have absolutely no flow bench data to back that up, its just a hunch. ok?

-- Joe

 

Good luck finding a y pipe made to outflow the one included with the 2055's. IMO, it's pretty much impossible. FYI, hooker uses 18 guage on their super competition headers to help reduce weight, which may not be significant, but every little bit helps. Besides, if you are gonna wrap them, like it says in the pic, or coat them, which I am doing, the thickness is pretty much a moot point. I'm gonna stick with the 2055's still being the best headers/y pipe combo money can buy. BTW, my collectors measure 2 inches exactly and can easily be opened up to the ID of the y pipe, which I also plan to do. I just cut the air tubes off last night and grinded down the welds, and it was pretty dang easy I must say.

EDIT: oops, I forgot you are a cop so I hope you dont arrest me for cutting the air tubes off, lol, just messin with ya.

 

I dunno. I got the flowmaster Y which has a longer transition than the 2055 Y. With some stainless mandrel bends, I don't see why the 2055 Y would be any better.

My headers are coated. Being done as we speak, inside and out. The y-pipe i'll just wrap, since wrapping actually works better than coating for heat retention (ask hooker, they'll tell you - thats why it voids warranty it warps the headers) and I don't care about the y-pipe.

For a direct-fit, yep.

I don't think anyone cares about your emissions in open-loop, which is the only place those tubes are used.

-- Joe

 

Dave at ACS (the company who coated my 2460s) made this custom y-pipe for his car. I'm having pretty much the same thing done, I think, except I'm using the flowmaster Y to do the 2.5 - 3 connection (prolly his most time consuming part). It should be fairly optimized for flow, and also will make the exaust work straight forward.

I'll either have the shop bend it, or I'll buy stainless bends (which you can see are really straight forward), and weld it up:

2.5 " Stuff
90d from left collector 81ZX2953P $10.99
45d from there 81ZX2930Y $9.99 <-- not sure why?
90d from there 81ZX2953P $10.99
90d from there, into the Y-pipe 81ZX2953P $10.99
90d from right collector, into Y-pipe 81ZX2953P $10.99

3" stuff
90d from Y-Pipe 81ZX2954Y $20.99
90d from Y-Pipe 81ZX2954Y $20.99

Total: $95.93

I'd prolly just weld the ends carefully, rather than cutting/using couplers. Add $1 to each of those bends, and you get an expanded end so can go that way too.

As for reducers, I'd have the exaust shop expand them to 2.5 ID so they slide over the mandrel pipe. weld in place.

Then wrap the whole y-pipe in header wrap (have it allready).

Then sell the flowtech headers/y-pipe/new cat.

Opinions?

 

and the 2055 y-pipe. Can't remember who took this pic. Looks like the pipes are constructed almost equally, with the exception of the Y.

 

They are part of the factory's certified emissions control system. Although nobody I've heard of does a sniffer test in open loop, the requirement is that the factory system be functional. That is verified visually in areas that are stickier about it (such as California and the Colorado front range - amoung others). Some places only enforce with a sniffer, others with just a visual.

Summary: Yes, there are those who care about the A.I.R. tubes.

(Technically, we're talking Federal law; so if you operate anywhere in the US on public roads without the system, you're breaking the law.)

 

well, from looking at the pics, it looks look a good y pipe/header combo. All I can say is good luck. I hope it turns out how you wanted it. Keep us updated and make sure to include pics.

 

I sure will. Details on each cut, each bend, where I welded it.. It will be like the howto for home-made 2640 y-pipes.

-- Joe

 

Heres an e-mail I recieved from Hooker. I asked if the 16g pipes had a smaller ID (one would assume after thinking it through).

>Our 2055 headers are not equal length. Yes, the 16 guage >headers will
>have a slightly smaller id. They will be .011" smaller. No, the >2055
>y-pipe is completely different.
>Thanks,
>Chris Reid

Now I think his math is a little off, but heres the scoop.

A 1 5/8 OD primary of 18 gauge is 1.52" ID
A 1 5/8 OD primary of 16 gauge is 1.50" ID

My Flowtechs which are 1 1/2 OD and 18 gauge are 1.404" ID

I'm curious what the difference would be in flow?

 

good point. I didn't even think of the difference in diameter. The 2055's might flow a tad more just because of that, but honestly I bet it is hardly anything to worry about.

 

Well the most important thing is primar diameter. Those gases are shooting into the pipes and need no restriction there.

-- Joe