Catalytic converters - same dimensions across NA1/NA2 or ?

[Speedmaster]

As the title states, I am trying to figure out if earlier, NA1 cars had different sized catalytic converters than say 1997 - 2000 and then 2001+.

I ask because I understood that to be one of the major reasons why OEM headers didn't line up to meet the CCs on install (never mind the connector setup AFTER the CC.)

I checked OEMAcuraparts.com and they use the same part number across the board.

Thoughts?

 

[DRIFTER]

They are different by year but interchangeable if you change it all out. So a complete exhaust system from a newer car will fit on the older cars.

91-94 cats are different then 95-99 and the 00-05 are different. I believe you could buy adapters for them I know Dali use to make them back in the day.

I don’t believe the cats were different size internally just different dimensions. Lots of people with older cars ran the newer style exhaust system swaps back in the day because the ones on the 3.2 flow a lot better and produced decent power gains on the older cars. Mainly due to a less restrictive header design. You could get them cheap when people upgraded there system and sold the stock stuff.

SOS has a high flow cat that replicates the OEM ones to trick visual if you need that.

I know when I changed mine out the internal dimensions were surprisingly small. I put Random Technology cats on my car about 12-13 years ago and they matched the headers and exhaust ID much better then the stock cats. I remember it being a noticeable difference on how the car felt and sounded after switching to a less restrictive cat.

 

[Speedmaster]

They are different by year but interchangeable if you change it all out. So a complete exhaust system from a newer car will fit on the older cars.

91-94 cats are different then 95-99 and the 00-05 are different. I believe you could buy adapters for them I know Dali use to make them back in the day.

I don’t believe the cats were different size internally just different dimensions. Lots of people with older cars ran the newer style exhaust system swaps back in the day because the ones on the 3.2 flow a lot better and produced decent power gains on the older cars. Mainly due to a less restrictive header design. You could get them cheap when people upgraded there system and sold the stock stuff.

SOS has a high flow cat that replicates the OEM ones to trick visual if you need that.

I know when I changed mine out the internal dimensions were surprisingly small. I put Random Technology cats on my car about 12-13 years ago and they matched the headers and exhaust ID much better then the stock cats. I remember it being a noticeable difference on how the car felt and sounded after switching to a less restrictive cat.

Thanks for the detailed response; much appreciated.

I'd like to throw my headers on (ceramic coated now) but don't want to do the job and find out mid-stream I need adapters. That would be no fun.

 

[DRIFTER]

Headers came in 91-94 and 95-05 dimensions. If you need to adapt a 91-94 header to a 95+ cat and exhaust SOS sells adapters separate.

As long as your headers are 95+ Dimensions it should bolt right up.

 

[Speedmaster]

Headers came in 91-94 and 95-05 dimensions. If you need to adapt a 91-94 header to a 95+ cat and exhaust SOS sells adapters separate.

As long as your headers are 95+ Dimensions it should bolt right up.

You sure on that? If so great.

But my understandig is...

91-94 & 95/96 are manifolds.

97-99 & 00+ are headers.

All meet up at cats (but arrive via different length manifold/header collectors. Post cats are where the adapters sit, if I recall correctly.

 

[docjohn]

the 97-99 headers are 2 inches longer than the 00-05..and the 91-96 manifolds are the same..the 95 and 96 cars were obd2 thus have different O2 sensor locations..

 

[Speedmaster]

the 97-99 headers are 2 inches longer than the 00-05..and the 91-96 manifolds are the same..the 95 and 96 cars were obd2 thus have different O2 sensor locations..

Thanks DocJohn (and others). Do you happen to know if the O2 placement in the headers is proximate for manifold and header? I am wondering if I will need extensions on the O2 sensors.