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Old 12-22-2014   #1
mike100
 
Join Date: Feb 2011
Location: San Marcos CA
Posts: 1,802
Default Anybody swap 93-95 (405hp) exhaust manifolds and cats to the early engines?

I'm considering splitting the difference between long tube headers and the highly compromised early manifolds. This will help me get through the emissions check and hopefully be worth a little extra pop over the early pipe set.

Do the later pipes bolt up to the cat back exactly the same or are the a different length?

Even worth it? I'll be keeping the headers on the back burner for a bit either way, but it would be nice to have the car quiet for a little while.
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Old 12-26-2014   #2
fletchusmc
 
Join Date: Nov 2013
Location: Jacksonville, NC
Posts: 48
Default Re: Anybody swap 93-95 (405hp) exhaust manifolds and cats to the early engines?

I've got my 95 up in the air right now. Will be more than willing to take any pictures or measurements for you.
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Old 12-27-2014   #3
Hib Halverson
 
Join Date: Jun 2005
Location: CenCoast California
Posts: 899
Default Re: Anybody swap 93-95 (405hp) exhaust manifolds and cats to the early engines?

Quote:
Originally Posted by mike100 View Post
I'm considering splitting the difference between long tube headers and the highly compromised early manifolds. This will help me get through the emissions check and hopefully be worth a little extra pop over the early pipe set.

Do the later pipes bolt up to the cat back exactly the same or are the a different length?

Even worth it? I'll be keeping the headers on the back burner for a bit either way, but it would be nice to have the car quiet for a little while.
In reality, the early manifolds are not "compromised." It's the late manifolds which are compromised...to the tune of about 5-hp.

Put the late manifolds on an early engine and you loose not gain power.

Be happy with your early "header cats".
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Hib Halverson
Technical Writer
former owner 95 VIN 0140
current owner 19 VIN 1878
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Old 12-27-2014   #4
mike100
 
Join Date: Feb 2011
Location: San Marcos CA
Posts: 1,802
Default Re: Anybody swap 93-95 (405hp) exhaust manifolds and cats to the early engines?

Quote:
Originally Posted by Hib Halverson View Post
In reality, the early manifolds are not "compromised." It's the late manifolds which are compromised...to the tune of about 5-hp.

Put the late manifolds on an early engine and you loose not gain power.

Be happy with your early "header cats".
I see, the 2 cylinders get cut short on the primary length as the merge into the bigger tube.
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Old 12-30-2014   #5
Hib Halverson
 
Join Date: Jun 2005
Location: CenCoast California
Posts: 899
Default Re: Anybody swap 93-95 (405hp) exhaust manifolds and cats to the early engines?

The 93-95 manifolds were changed to eliminate a reversion problem which, if the engine was in decel and any cat substrate was loose in the space ahead of the cats, it would get sucked into a cylinder though an open exhaust valve and damage the engine.

Unfortunately, that cost 5-hp but they gained 35 from the changes made elsewhere in the engine so the net was 30-hp.
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former owner 95 VIN 0140
current owner 19 VIN 1878
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