Classic Mustangs List Archive

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Mail From: (email redacted) (email redacted)

Thanks for taking over the list. I was upset when I had no interesting
questions to read.

Anyway, what do you all think about putting 3" catalytic converters on
my 70 SportsRoof?? I know I don't need them but I like to be "Green".

I would put them after my Dr. Gas crossover and long tube headers but before
any pipes or mufflers. I have a 302 -2v soon to be 4v.

How would these affect torque and HP??? I will follow them with 2.5" pipes
and mufflers.

Brian

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Mail From: Michael Gilbert Girolami (email redacted)

Can someone tell me how to un subscribe

Michael Girolami
Communication, Electronics
& Computer Systems Engineering @RMIT
Email : (email redacted)

This read-only message was archived from a public mail list.
Mail From: Keven D. Coates (email redacted)

>Anyway, what do you all think about putting 3" catalytic converters on
>my 70 SportsRoof?? I know I don't need them but I like to be "Green".

Brian,

There are certain things to consider when you try to retrofit emmissions
equipment.

If you want to put on catalytic converters you better be completely sure about
your fuel mixture. If you aren't running the correct mixture, you will clog
your cats and all that money you spent will be worthless to everyone.

You must run either fuel injection, or an emmission carb. You also can't run a
certain type of camshaft. Of course you must also unleaded gas.

Fuel injection would be ideal, but expensive, and hard to fit to your car. An
emmissions carb from Holley or others would work with some tuning, but I don't
know how they are on performance. The camshaft thing I am not completely sure
about, but I know that you can't allow too much overlap in the cam, or too much
raw fuel and air go out the exhaust valve (as is common when running a high
duration cam at low rpms) and it will foul the cats.

As I'm sure you know, catalytic converters are not magic emmissions solutions.
They simply take a very specific mixture of chemicals (combustion chemicals)
and convert them to other chemicals that are better for the surrounding area.

They need that certain mixture to work, and they are very specific. They also
run very hot, so you might want to put a heat shield above them or you could
ruin your carpet inside your car or maybe even start a fire.

You might not have too much horsepower loss with such big converters, but if
you run an emmission carb and cam you will probably lose some there. If you
can convert to fuel injection, then you can have both horsepower and emmissions
that work reasonably well together.

I am certainly not an emmissions specialist, I may be wrong on some points, but
this is my idea of how it is. Good luck!

Best Regards,
Keven Coates
'68 bent stang

Best Regards,
Keven Coates
(713)274-2656

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Mail From: Eric F. Riggert (email redacted)

Brian wrote:
< Thank you to the new admin clipped - thanks from me too!!>
> Anyway, what do you all think about putting 3" catalytic converters on
> my 70 SportsRoof?? I know I don't need them but I like to be "Green".
> I would put them after my Dr. Gas crossover and long tube headers but before
> any pipes or mufflers. I have a 302 -2v soon to be 4v.
> How would these affect torque and HP??? I will follow them with 2.5" pipes
> and mufflers.

Brian,

2.5" cats (and exhaust) is more than enough for a 300HP 302. This is
what's going on my modified '94 Cobra. (Stock Cobras have 245
advertised HP and a 2.25" exhaust, with 4 cats, 2 per side).

Also, you need to put the cats as close to the heads as possible, since
they have to be hot to work (right guys?). Leaded fuel will kill them
in a hurry, as will raw fuel (so I think a modified car with no feedback
emissions - either vacuum or electronic - equipment might hurt them
pretty fast, and then you are out your $200+). When they die, they melt
internally, and plug up the exhaust. Symptoms are no power above a
certain (low, like 3000) RPM, and the engine gets very QUIET at above
that RPM...

Regards,
Eric Riggert, '66 Mustang GT, '88 LX 5.0, '94 Cobra, SCOASCC, SMA
(email redacted)

This read-only message was archived from a public mail list.
Mail From: Sammy (email redacted)

On Tue, 29 Oct 1996, Eric F. Riggert wrote:
> Brian wrote:
> < Thank you to the new admin clipped - thanks from me too!!>
> > Anyway, what do you all think about putting 3" catalytic converters on
> > my 70 SportsRoof?? I know I don't need them but I like to be "Green".

Why? I have heard they don't make that much difference, they also rob
power, and cause lots of heat under your floorboards. I was reading about
the new 5.0 intyo an older 'Stang conversion, they mentioned that the cats
did not have to be retained even though the rest of the emissions system
needed too. This was because of safety. Think about the polution if your
car was burning on the side of the road...
-srw

> > I would put them after my Dr. Gas crossover and long tube headers but before
> > any pipes or mufflers. I have a 302 -2v soon to be 4v.
> > How would these affect torque and HP??? I will follow them with 2.5" pipes
> > and mufflers.
>
> Brian,
>
> 2.5" cats (and exhaust) is more than enough for a 300HP 302. This is
> what's going on my modified '94 Cobra. (Stock Cobras have 245
> advertised HP and a 2.25" exhaust, with 4 cats, 2 per side).
>
> Also, you need to put the cats as close to the heads as possible, since
> they have to be hot to work (right guys?). Leaded fuel will kill them
> in a hurry, as will raw fuel (so I think a modified car with no feedback
> emissions - either vacuum or electronic - equipment might hurt them
> pretty fast, and then you are out your $200+). When they die, they melt
> internally, and plug up the exhaust. Symptoms are no power above a
> certain (low, like 3000) RPM, and the engine gets very QUIET at above
> that RPM...
>
> Regards,
> Eric Riggert, '66 Mustang GT, '88 LX 5.0, '94 Cobra, SCOASCC, SMA
> (email redacted)
>

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This read-only message was archived from a public mail list.
Mail From: (email redacted) (email redacted)

Thanks Eric!

I'll check it out!! When I decide if I am rebuilding or replacing my
engine I will know how simple this conversion (EFI with CATs) will be.

Brian