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1998 2.5L 2.5" Exhaust Build


simpler=better

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Jul 9, 2009
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Vehicle Year
1982
Make / Model
Mercedes
Transmission
Automatic
Went home for the weekend and got some shop time with my Brother & Dad. Since my hacked up stock exhaust was rattling, loud, rusted, and had a cracked EGR tube we started from scratch. Truck is a 1998 XLT, 2WD, extended cab, stickshift, with AC & PS. ~210k miles on her right now.

Parts:
Junkyard header & EGR tube from another Ranger (95? not sure on the year)
M10x1.5 30mm long SHCS from McMaster-Carr http://www.mcmaster.com/#91290a522/=oy43ww
"Thunderbolt" corrugated steel 2.5" cat http://performance-curve.com/25thunderboltmetalliccatalyticconverter415250.aspx
Mild steel O2 bung http://performance-curve.com/universalo2nutpair.aspx
Mild steel mandrel "J" http://performance-curve.com/aluminized-25mandrelbend.aspx
Flex pipe http://performance-curve.com/25x6.aspx
Band clamp http://performance-curve.com/bandclamp25304ss.aspx
Louvered resonator http://performance-curve.com/A3518S-8-C8-IB.aspx
2x 50ft 1" exhaust wrap (pick your favorite color) http://www.siliconeintakes.com/product_info.php?cPath=10&products_id=566&osCsid=0f27ebb908e0ab9b65ebd60ff945dc6e
2.5" mild steel vband flanges http://www.siliconeintakes.com/product_info.php?cPath=10&products_id=324&osCsid=0f27ebb908e0ab9b65ebd60ff945dc6e
2.5" vband clamp http://www.siliconeintakes.com/product_info.php?cPath=10&products_id=313&osCsid=0f27ebb908e0ab9b65ebd60ff945dc6e
Walker #18132 muffler (rock auto)
DPFE hoses # M40001 (rock auto)
EGR gasket & exhaust gaskets #MS92424 & #70149 (rock auto)
Nickle-based anti-size (this stuff is incredible-I'm a convert) http://www.amazon.com/Permatex-77124-Nickel-Anti-Seize-Lubricant/dp/B0002UENJ2
Rustoleum 1,000°F BBQ paint, brush-on (found at W*lmart)
3/8" mild steel rod for hangers (local hardware store)
2x 24" sections of straight pipe (local auto parts store)

Parts I had kicking around :
Lock washers for the bolts
Hose clamps for the header wrap
Safety wire for the header wrap
Old spark plug to put into the O2 bung while welding to keep it from warping

If I did it again I would have used 1" wrap for the header, and 2" wrap for the cat/ downpipe. The blue dye burned off almost immediately on the header itself but not the EGR tube.
Also, the front hanger needs 1/2" diameter rod, not 3/8"

Grind and knock the header bolt tubes off:





Cut the awkward flange off. The collector is ~ 2.5" diameter at this point.



Welded straight pipe onto the header to clear the starter, down to the cat, then down to a 45° bend, ending at the vband clamp. The tubing is pushed through the vband ~1/4" to help it seal properly.











It goes header->2.5" pipe->cat->elbow->vband->resonator->flex->muffler->tailpipe
The header, car, and resonator were painted, wrapped in fiberglass, and painted again. The EGR tube is wrapped as well but I didn't bother painting it since it won't ever see water or salt.

ASSEMBLE THE VBAND CLAMP AS A WHOLE before welding or you will warp it. Also, use the nickle neversieze.
Neversieze the spark plug and put it into the O2 bung while welding, otherwise the heat will warp the threads...ask me how I know.



Performance:
If you don't do anything else, wrap the header and EGR tube. That dropped my under-hood temps by A LOT. I don't get blasted in the face by a heat wave when I open the hood. Moving the cat forward, and wrapping the cat/resonator has cut down on the cab-floor heating. My wife can now put her bag on the floor without worrying about it melting :)

I didn't notice any real difference at the low end, it felt about the same as my hacked up 2" stock exhaust. From 4k-5k it seems like it might be faster, but I don't have any dyno runs to prove anything. I drove it home 8 hours, all highway. She performed more or less the same as before.


It's about the same noise level at idle, except with no rattling
It resonates pretty badly from 1800-2200 rpm.
3,000rpm is darn close to silent.
4,000rpm is about as loud as stock, maybe a little louder. Not unbearable.

I'm going to play with it some more to get rid of the resonance. Probably swap on a 2" tail pipe after the muffler, or stick a motorcycle baffle into the 2.5" tail pipe. If I need to add a baffle between the cat and resonator it will be super easy with the vband flange.


I'll snap some pics on my lunch break under the hood and outside the truck.


Other stuff about the truck:
Generic electric fan with an on/off switch from a 2.3L fox body. Kicks on at 210°F and off at 185°F. It only kicks on when I'm stuck in traffic or let it idle for 20+ minutes. It almost never kicks on from November-April.
Blocked off the throttle body coolant loop, because it kept getting in the way.
Port matched the upper intake tubes (they were almost perfect from the factory, so no gain there)
Replaced the airbox's 1.5" velocity stack with a 2.5" cut up plastic funnel/rivets (for a quieter intake, no power goal there)
CAM2 10-30 synthetic blend oil, WIX 51515 filter, Wolf's head synthetic ATF, Mobil1 75-140 in the diff
All other maintenance is kept up (fluids, spark plugs, timing belt, thermostat, etc.)
It usually gets 23mpg around Baltimore. Got 25mpg on the long trip home, at a steady 65 up/down hills. I can probably stretch it to 27 if I slow down on the hill climbs.
 
Last edited:


simpler=better

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Joined
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Messages
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Vehicle Year
1982
Make / Model
Mercedes
Transmission
Automatic
Under the hood:



 

simpler=better

New Member
Joined
Jul 9, 2009
Messages
210
Reaction score
0
Points
0
Vehicle Year
1982
Make / Model
Mercedes
Transmission
Automatic
Until I have time to make a Helmholtz tube like the Mustang guys, I present to you the redneck resonant-frequency-changer. It's now quiet up to 2,500rpm, and resonates around 3,000 but only when I'm above half throttle. Not perfect, but an improvement.


 

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