1998 SC2, MagnaFlow Exhaust Question

[bumpdraft]

Does anyone know what the differences are between the Heavy Metal Grade Federal vs. the O.E.M. Grade Federal ?

I know the Heavy Metal has more catalytic material, but is there any other difference?
What makes me wonder is the fact that the “better” HM catalytic converter costs less than the “worst” O.E.M. catalytic converter.

Is one more restrictive to exhaust flow than the other?
The images appear to be CADD drawings, so differences might not be apparent.

HEAVY METAL


O.E.M.


This could be a dumb question because I submitted it to MagnaFlow thru their contact question form and have received no reply....

[Macgyver]

The OEM one is likely California/CARB compliant and has more catalyst material for better emissions. Fed spec is more than enough for the other 49 states. Both will be stainless steel, I don't think Magnaflow even makes mild steel components.

[bumpdraft]

Originally Posted by Macgyver

The OEM one is likely California/CARB compliant and has more catalyst material for better emissions. Fed spec is more than enough for the other 49 states. Both will be stainless steel, I don't think Magnaflow even makes mild steel components.

That sounds plausible, but both the HM and the OEM website images have a disclaimer, “Not for sale in California”.
Maybe the HM is for California-type emissions requirements in states like New York, yet the HM doesn’t meet the current, ever-stricter CARB requirements. That seems to agree with what I could find on the MagnaFlow website...but it would be nice if they would come right out and say it.
Thank you

[bumpdraft]

I guess it is possible that the HM has to be connected to the MagnaFlow HM Manifold.

[bumpdraft]

Originally Posted by Macgyver

The OEM one is likely California/CARB compliant and has more catalyst material for better emissions. Fed spec is more than enough for the other 49 states. Both will be stainless steel, I don't think Magnaflow even makes mild steel components.

It seems like there is an emissions penalty built into the price.
Meeting only the Fed emissions costs $69 more than meeting California/CARB.
The O.E.M. costs $69 more than the HM.

[TomM96]

I've spent a few hours looking around the net for my car, which will get a new exhaust.

I detect bullxxxx. My guestimate is that the Saturn OEM cats have rectangular honeycomb matrix in the canister. Walker sells replacement cats with such a matrix, and that was the Saturn OEM in my '97 DOHC.

The Sat OEM 'precat' on the Ex Man of a '99 also has that rect matrix honeycomb.

I THINK the later LEV CARB compliant employ another type element, which
has Slightly higher resistance to flow... which consists of American-made cannisters with an interior material filler that is a COIL of corrugated
metal sheet with ceramic substrate deposited thereon.

I think the Sat OEM is probably imported- it requires precision manufacture.
The corrugated coils are just wrapped up and slid into place … thus not-so-precision.
Where the Sat OEM & Walker rectangular matrix have equidistant square 'holes' for exhaust flow,... the newer stuff - corrugated - is fit in a wrapped
coil; the 'holes' are curved shape like almonds, but compressed-- so the flow will try to stay in the middle of a tapering elliptical aperture.

They probably both work. The HM may just refer to the heavier gage of the sheet metal comprising the tubes/cannisters, which might resist corrosion longer. JUST GUESSING. I got a used ExMan with precat from one wrecking yard, and I want to inspect some parts from a LEV CARB compliant vehicle before I buy my replacement.

iT JUST OCCURRED TO ME THAT THE REASON WHY THE JUNKYARDS DO NOT USUALLY SELL THE CATS <ASIDE FROM LEGALITY>, IS THAT THEFT WAS A PROBLEM, AND THE LEGISLATORS DON'T WANT THE WRECKING YARDS TO BE A GOOD MARKET FOR STOLEN CATS.

ANYBODY ELSE ?

Too bad the customer service has not replied in transparent fashion.

[bumpdraft]

Thanks for the good information.
I wonder if MagnaFlow’s O.E. and HM both have the same corrugated coils and the only difference is the amount of catalyst deposited on the coils. It doesn’t seem likely that there is more than one type of corrugated coil.
Customer service: I looked more closely at the specifications on MagnaFlow’s website, and the over-all length is the same for both the O.E. and the HM. So maybe my “fit” question was not a good one

The Walker sounds good, but it is the pipe forward of the converter that fails first. I am shopping for a stainless steel system from the converter forward to the exhaust manifold. The MagnaFlow system looks good in Magnaflow’s CADD drawings.

My 1998 original converter had AC Sparkplug stamped on the shell. I remember being in the AC Sparkplug model shop and seeing ceramic extrusions for converts sitting on a shelf. I think they were for diesel...
(That place had a 5-axis E.D.M. that could cut to 4 decimal places; Could have been 5 decimal places if the machine’s foundation would have been more substantial. 4 was good enough for their purposes, ...I was told...if I remember correctly...Walking into that place had the feeling of walking into Mission Control at the Kennedy Space Center)

[TomM96]

> The Walker sounds good, but it is the pipe forward of the converter that fails first.

10-4 on that; I've replaced three

I wonder if the 'OEM' designation means just that: from the car manufacturer.

It's possible that some of the aftermarket items are functionally superior to the OEM... but, lacking the (OEM) designation … they are Illegal.

Maybe allowing aftermarket competition would mean maintaining a testing facility to qualify aftermarket entrants/products.

[TomM96]

> seeing ceramic extrusions for converts sitting on a shelf. I think they were for
diesel...

The filler material of the cat for my '95K3500(6.5L hi output diesel) was exactly
same as my '97SW2 (to human eye) square box honeycomb.

[bumpdraft]

UPDATE

On 4-27-2021, possibly because I am tooostupid to comprehend their website and have no business considering a purchase of a performance product , I submitted a question to Magnaflow, trying to figure out why one product costs significantly more than the other.
Question:
“Magnaflow,
The descriptions for 49530 & 24411 are exactly the same. Please, relative to my specific engine, what is the difference between 49530 and 24411? (Saturn 1998 DOHC SC2) Why is there additional cost for the more expensive 49530?
Note that my 1998 SC2 has only one (1) catalytic converter. My 1998 SC2 does not have a converter on the exhaust manifold. Does 24411 attach to 24998? Thank you”

I will update, should there be reciprocal joy received from Magnaflow.

[fetchitfido]

While I agree the aftermarket not knowing what/how their parts fit the S-Series is stupid...GM/Saturn changed it quite often.

Applies to DOHC's, SOHC's likely have similar changes:

• Manifolds:
  • 4-2 header '91-'92
  • Fed spec manifold '93-'98
  • Cali spec manifold '96-'98
  • Fed spec manifold '99-'00 (no air pump)
  • Cali spec manifold '99-'02 (air pump)

• Downpipes
  • 2-1 downpipe '91-'92
  • Fed spec downpipe '93-'95
  • Fed spec downpipe '96-'98
  • Cali spec downpipe '96-'98
  • Fed spec downpipe '99-'00
  • Cali spec downpipe '99-'02

Cat-back:
I believe emissions level has no impact, though the one for the 4-2-1 system has a giant square 4-bolt flange instead of the 2 or 3 bolt flange used on '93+.

[TomM96]

Update on my efforts:
1) the 'ceramic' style IS the honeycomb matrix (it looks metallic, but
I now think it is ceramic). The precious metals are then Added to the
ceramic honeycomb.
2) The parts 'look up' on these is very challenging/confusing.
3) The retail sale price for the Walker 15842 generic CatCon for pre-1999
has gone up from about 150 ... to ~$200.oo. {RockAuto prices}
4) I believe Some of the pricing is odd... since some prices have not been
adjusted UP from what they were before the recent escalation in the
cost of platinum, palladium, and rhodium.
5) Last winter I shopped for a Cali-NY Catcon/downpipe for my 2000 SW2;
I expected to buy from Bosal, since that was what Chaos found worked
on his 3-Gen. But Bosal seemed to have removed their product from the
lineup. The only one I found that seemed like it would meet the Cali spec
was from DEC-Diversified Environmental Catalysts... the piping is only
Aluminized steel. Both the input and exhaust flanges feature a flat flared
pipe that is secured by compression of the flange-- the flange is free to
rotate, it is not welded. The cat features a honeycomb matrix, which i
now understand to be ceramic.
...
It cost ~$385 before ship+tax, ~$425 on arrival.
...
If i use it it will be painted with the VHT hi temp paint....
....................
Address:
DEC Catalytic Converters 2841 W. Clarendon Ave.
Phoenix, Arizona 85017 United States
https://deccats.com/contact-us/
.................................................. ...
There are mixed reports about Magnaflow. Bill had to mess with the
rotation/clock of the flange, which was welded.

If they respond to Bumpdraft email, he should ask also about the stainless alloy grade. It is likely 409. They like the #409 because it does not harden or change shape as it undergoes the thermal cycles, which some metals do. It is the OEM material = ~ 10 years.
................................................
................................................

THANKYOU Fetch for the classification of the downpipes, by year and
Fed vs Cali application.
.................................................

I am also considering WRAPPING the downpipe with a ribon/tape designed for header application. The tape will keep the heat in the pipe, and likely
keep salt water OFF the metal.

[bumpdraft]

Okay, the good people at Magnaflow have replied:

Good afternoon,

The only difference between the two converters is the different grade so OEM to HM. OEM grade will be for vehicles registered federally but still came from the factory with California emissions equipment or a California computer where as the HM is for heavy metals and has less amounts of precious metals inside and would throw a check engine light on a California vehicle. Can you provide me with the vin or the entire vehicle specifications just so that I can clarify parts for you and figure which parts would mate to what. If you have any further questions please contact us at 1-800-990-0905 anywhere between 7am-5pm PST.

Thank you.

Technical Support

Originally Posted by bumpdraft

UPDATE

On 4-27-2021, possibly because I am tooostupid to comprehend their website and have no business considering a purchase of a performance product , I submitted a question to Magnaflow, trying to figure out why one product costs significantly more than the other.
Question:
“Magnaflow,
The descriptions for 49530 & 24411 are exactly the same. Please, relative to my specific engine, what is the difference between 49530 and 24411? (Saturn 1998 DOHC SC2) Why is there additional cost for the more expensive 49530?
Note that my 1998 SC2 has only one (1) catalytic converter. My 1998 SC2 does not have a converter on the exhaust manifold. Does 24411 attach to 24998? Thank you”

I will update, should there be reciprocal joy received from Magnaflow.

[TomM96]

Just goes to show-- nothing like good communication, which is what
customer service can be. Efforts at interpretation/analysis fail by comparison.

George Shultz wrote an opinion essay during the Trump administration, largely
to state that 'trust' precedes agreements. In foreign policy, accurate intelligence, founded on historical analysis and espionage, is very valuable
..... and mis-interpretations abound.

Among analytic chemists, metals are "base", OR "precious"="noble".

So @ Magnaflow, OEM=OEM -> high precious metal ;

while Heavy Metal indicates 'mostly base metal', or Low precious content.

[bumpdraft]

UPDATE

Planning ahead, narrowing it down, I asked Tech Support more questions:

My QUESTION #1:
Does Magnaflow make a pipe and catalytic converter assembly to fit a 1998 SC2, engine type LLO Duel Overhead Cam (DOHC).
1G8ZG1271WZ****** Federal Emissions
DUEL OVERHEAD CAM, DOHC 1.9 Liter
Original Equipment P/N: 21013080 PIPE ASM-EXH MANIF (this is the O.E. down-pipe & catalytic converter assembly that is on my car now)

MagnaFlow ANSWER #1:
Thank you for contacting MagnaFlow Tech Support. We in fact do offer converters for your model, please refer to the following part numbers and information provided.

Pre-Cat
Part # 24998 - Rear - HM Grade Federal / EPA Compliant Direct-Fit - "For OBDII Federally registered vehicles with Federal/EPA Emission systems."

Down-Pipe & Catalytic Converter Assembly
Part # 49530 - OEM Grade Federal / EPA Compliant Direct-Fit - "For OBDII Federally registered vehicles with California or Federal/EPA Emission systems."


My QUESTION #2:
My 1998 SC2 Engine: LLO 1.9 Liter Duel Overhead Cam does not have, and never did have, a Pre-Cat, only a cast iron manifold.
Will Part # 49530 attach directly to the cast iron manifold, WITHOUT the use of Part # 24998 ?”

MagnaFlow ANSWER #2:
In that case, its sounds like you have a Federal emissions vehicle. IF the OE manifold matches the design of the # 24998 minus the converter, then part # 24411 or # 49530 might work.
The odd note I see is "California Emissions Equipped Vehicles Registered Outside Of California" for both products. Indicating to me, that we unfortunately, only offer products for 50-State or CA emissions compliant models.

——————————
——————————
Summary:
For a 1998 DOHC, it seems that the MagnaFlow down-pipe will not bolt directly to a cast iron manifold.
Meaning, the MagnaFlow down-pipe will only bolt to a Saturn Pre-Cat manifold
or
The MagnaFlow down-pipe will only bolt to a MagnaFlow Pre-Cat manifold.

Enter the MagnaFlow Part # into the MagnaFlow website for more information.

[TomM96]

I think fetchitfido post #11 explains how it might be hard for the
aftermarket to get it right.

I don't know about the 'OEM' vs 'HM'. I think sometimes the 'HM'
(or similar annotation) indicates "high-precious metal-content", as
for Cali / ELEV vehicles specification, OR to clean up the exhaust from
old/high-mileage engines.

Sooo two considerations might cause price variations:
1) variation of amount of precious metals incorporated into the particular
CatCon.
2) Different material composition of the piping from manifold to/from
the CatCon. OEM downpipes usually made from ferritic SS 409,
desired because it does not warp after hot-cold cycles. It lasts indefinitely
if operated in dry desert, but is very vulnerable to corrosion degradation
if exposed to roadsalt. They last more like 10 years; the 'plain' low
carbon steel pipes like my DEC, and the Walker product line, last only
about 5 years. I painted my DEC downpipe & Catcon with VHT,
and might remove it each summer to touch up scratched spots.

Again, I dunno what's up with the aftermarket information.
I would suggest maybe check out the Walker product -- it worked fine on
my '97, except for the corrosion factor. And the last one I put on, I attempted to paint with the VHT, which appeared to only minimally rust in the first two years ... before the car was martyred.

* * *
IFF you are not in a rush, AND if you find a muffler shop which bends/welds their own exhausts, you might consider
having a downpipe made which gets clamped-OR-welded to a Walker or D.E.C. catcon.

I was considering that at one point, and I located a supplier of 18-8 (SS304) AND 316 (SS316) tubing suitable for exhaust.
I'm pretty sure that if you fitted a 316SS downpipe, it would likely last 'life of vehicle', based upon my experiment using
Carpenter20, and SS316 for the exhaust flange at the aft end of the CatCon, which seems to be the HOTTEST point in the
exhaust system (aside from interior of catcon). Those fastenings, which get dramatically deformed in roadsalt service with
carbon steel, showed NO Tarnish with SS316 after 10 years exposure (2-downpipes worth).

I can look up the tubing dealer (cheap, too, maybe $30--$60 for a downpipe, IIRC)... but its on a dead HDD.

[bumpdraft]

TomM96, That is all good info. Let’s hope it doesn’t disappear.

I am trying to find that elusive, perfect MagnaFlow vs. cobble something together.
DOHC only.
#24411 OverAllLength 41.25”, Year 1996-2002 magnaFlow.com
#23450 OverAllLength 45.3”, Year 1996-1997 ebay & magnaflow.com
(insert Fetchitfido’s manifold info....and think about it)

My spare O.E.21013080, that has a hollowed-out Cat, OverAllLength measures ~50”
https://imgur.com/a/BGdSRhQ
https://imgur.com/a/sDun34H

Also, from eBay, #23450 uses a 2” diameter pipe.
The I.D. of my spare O.E.21013080 is 1.875” at the inlet.

It appears that #23450 is the closest fit for a 1998 DOHC Federal Emissions with a cast iron manifold without a Pre-Cat.

[KevinVarnes]

Some information in this thread on pre-cat no pre-cat downpipe fitment. It looks like the same downpipe should fit either manifold style.

http://www.saturnfans.com/forums/sho...d.php?t=146671

Also, when they quote overall length who knows how they are actually measuring it or how accurate the measurement is. One guy could have measured diagonally from the manifold flange to the rear converter flange and another guy from the manifold flange horizontally back to the rear converter flange. I wouldn't put much stock in those numbers.

My guess is 24411, 23450 and probably the 49530 all fit the same. The real question is whether Magnaflow has sorted out the flange welding. I've seen several 8-10 year old reviews indicating issues with fitment related to the flange being welded out of position. It could also be operator error and maybe people ordered a part thinking they had a DOHC when they really had a SOHC. Overall, the Magnaflow looks like the only bolt in option with full stainless steel construction available (unless you find a Saturn NOS part somewhere).

[fetchitfido]

The Cali manifold is 6in longer than the Fed (at least for 2nd gen, '96-'99). The flange itself is probably the same but it's clocked to a different position on the 'circle', a different angle from 'level' and at a 6in different height.

I didn't understand it either until I had both parts in my hand.

[TomM96]

@ post #17

> Also, from eBay, #23450 uses a 2” diameter pipe.
The I.D. of my spare O.E.21013080 is 1.875” at the inlet.

OK ... but exhaust line is "tubing", which diameter is specified O.D.,
whereas water piping is specified, nominally I.D.

So, the 1.875 inlet is likely 2" O.D.
When i bought U-bolt clamps from a knowledgeable local FLAPS,
I asked for 2-1/4" clamp, and he said, try this 2-1/8" clamp --
I think I was clamping the front of the OEM catcon over the OD of the
Walker downpipe (which 2.0" OD tubing, I think).

...............
...............
re- It appears that #23450 is the closest fit for a 1998 DOHC Federal Emissions with a cast iron manifold without a Pre-Cat.

This consistent with Fetch (6" diff) comment. It is the vertical down
section which is much Shorter with the pre-cat.

My '97 (cast mani without pre-cat) had long drop section.

For '99 I have a Fed downpipe & precat, and my 2000 has Cali/ELEV
pre-cat... both are short down sections.

I tried to buy a Cali pre-cat so I could compare/measure flange
rotation, etc off car, but unable to consumate the transaction.
Thus, I was interested to observe that the D.E.C. downpipe-catcon
which I eventually bought (Rock at the time wasn't stocking Borla)
had a rotating flange to fit whatever the pre-cat flange configuration
was set at.

The telephone customer service at D.E.C was very helpful.
Mine came slightly kinked in the flexpipe section, as though the
deliveryperson dropped the box, which flexed (box torn, too).
D.E.C. advised that if it did not work, I could just return the item.

I attached a vacuum to check for leaks, and it seemed OK ... I stored
the box vertically in my bathroom temporarily, and the flex bellows
inside the braided wire cover straightened itself out, relieved of gravity.