I'm doing a little research on exhaust and was looking for some opinions on these. (Yes, I searched and didn't find the answers I was looking for).
First: Can you use cats with these? If so, where do they go? single or dual?

Second: Do these mandate a true dual exhaust? Any body have pictures of their setup?

Third: Would these be too much for my (stock) ZZ4? How about a 350/383/400 pushing 400rwhp (my final goal)?

Here's my requirements/info:

Must support 400rwhp.
Must be quieter and sound better than open headers.
Have to be able to use an O2 sensor. Heated is ok.
Have to have cats. Single or dual doesn't matter. Location doesn't matter.
Have to have mufflers. Single or dual doesn't matter. Location doesn't matter. Tailpipes must exit straight back under bumper.
Dual system (if required) must utilize a balance or crossover pipe.
Pipes must clear Moser 9" Ford rear, Steve Spohn retrofit T56 crossmember/torque arm, and Global West SFCs.

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"Beware he who would deny you access to information, for in his heart, he dreams himself your master"

'84 Black Camaro ZZ4 M5 (V-6 in a former life) -- street beast
'91 Medium Blue Metallic Z28 A4 (UB-HSTRY's old ride) -- currently broken
'99 Navy Blue Metallic Firehawk #120 M6 (99.44% stock) -- daily driver

 

99Hawk,

I am swapping my SLP 1-5/8" headers for the Hooker SuperComp Long Tubes (HSCLT). These headers are the ultimate for performance. The cons are that this exhaust system is the most expensive exhaust system to buy. $400 for headers, $250 for coating, and $250 for Mufflex Y-pipe. That's at least $900. If you want to do it right then you will want to buy 2 Y-pipe kits from mufflex: one that will serve as your off-road pipe and one that will serve as your emissions pipe. Tack an extra $250 and two cats for $100 each and the price jumps to $1350. Tack on professional installation because the Y-Pipe from mufflex MUST BE WELDED TOGETHER then you are looking at close to $1500. Add on a Mufflex single 4" system and that puts the total cost of the exhaust system at $2000. That is a fookin' lot of money!!!!!! But, this is the only system that will support serious horsepower. The biggest problem with headers that are currently on the market is that there is no 1-3/4" header that has a 3" outlet except for the HSCLTs. The SLP's totally suck in this area because their advertised 2-1/2" collector actually necks down to 2-1/4" up in the collector. I'm sorry but 2-1/4" collectors just don't work on cars with big horsepower.

Anyhow - to get to your questions ... I have done A LOT of research in this area to attempt to find everything that might cause this installation to go awry.

1) O2 sensor should go in the TOP of the driver's side collector (i.e. should be pointed UPWARD). I had IRS weld the O2 bung in this position from the shop.
2) MUST use a heated O2 sensor. I think the PN is a Bosch 3177 heated 3 wire sensor.
3) I have heard that the stock oil cooler gets in the way. I removed mine.
4) I have heard that the knock sensor located in the passenger side of block gets in the way. I am relocating mine to the driver's side of the block.
5) I have heard that you need a smaller starter. I am lucky because I already have a ministarter on the car.
6) I have heard that you have to jack the engine up and slip the headers in from the bottom. You'll need to remove the oil filter on the driver's side and possibly the starter on the passenger's side.
7) Assume you will have to bend some brake lines around.

Yes, you can run catalytic converters with the HSCLTs. But, there is no 'bolt-up' installation. Using these headers requires fabrication. Mufflex has a Y-pipe for us thirdgenners who want to use these headers. However, it comes in pieces and you have to weld it up. It is a 3" Y-pipe so imagine having to mate that to cats somehow. Luckily, I will most likely be driving to Mufflex (about 3-1/2 hours away) and I will get their 3" Y-pipe but ALSO have them fab a 2-1/2" Y-pipe with cats.

You do not need a dual exhaust system. Their Y-pipe is meant for the single exhaust system.

Its a tough and costly install but there is no other substitute. Now - please keep in mind that I have not done this install yet. I am just passing along all the information that I have discovered from others.

A cheaper alternative is to have cutouts welded into the Y-pipe so that you don't have to worry about upgrading your stock single 3" exhaust pipe with a Mufflex 4" system.

The HSCLTs will work great on a 350. What really will determine how much power you make is your choice for the REST of the exhaust system.

Tim

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• Program your own PROMs!. Read my article to get started!
• Research and Experiment before asking questions.
• This is not a chip store. Go to the classifieds if you want someone to sell you a chip or give you a BIN.

TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

I too don't live that far from Mufflex (4hrs?) so I would most likely have them do all the fabrication work. Bolt up is not an issue.

Couple more questions:

You say you don't need a dual exhaust system for this. That's great! But, now my curiosity has got the better of me and I wonder if Mufflex could somehow fabricate one. Yes, I like to have all the information I can get .

I assume I can "jack" the motor up with my engine lifter and/or install the headers on the motor with it out of the car.

What HP level do you think the Mufflex 4" becomes a necessity?

I was hoping to stick with just one Y pipe, with cats. Can that be made to work with the 3" pipe?

 

well...i personally dont feel that one should spend that much money and have 2.5 inch cat(s). i personally have the LTs on the way and will get the y pipe from IRS...i hear its cheaper from them than mufflex....hook that up to my Random tech 3 inch cat...and the rest of the exhaust is 3 inch too. maybe one day 4 inch will be needed. they are gonna go on a 305 for now...and expect to lose a LOT of torque...but that fine...cuz the 400 will be in in no time. anyways....i found it cheaper. 360....from muscle motors (GP) i think its still goin on

im not gettin em coated....just gonna put 1200* ceramic paint...about 30 coats.

the y pipe is supposedly 200 from irs

my cat cost about 200.

the catback varies. mine is under 200. hooker.

anyways....traxion is right....they are the only feasible choice for serious power.
good luck.


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Rick
90 Camaro RS 305 TBI
400 small block, Hooker 1 3/4 LTs, Random Tech Cat, Hooker aero chamber cat back on the way!!
TH700-R4 with Trans-Go shift kit (corvette servo here...but not installed yet)
MacEwen Motorsports White Gauge Overlays
14" K&N X-Stream Open Element
GTS Headlight and Taillight covers
5% Limo Tint all around
Classic White Chevy Bowtie sticker on rear window
http://www.geocities.com/esvalenz

Man if my camaro were a rice-rocket all those mods would give me what...easily 50-60 hp!!!

"Just because I've done it, doesn't mean I knew what I was doing!" - Me