To Cat or Not to Cat??

[1batt4u]

Hi all,

I rememebr reading, without the catalytic converters the Delorean has around 170HP. Sound right??

I am in the processs of changing the whole exhaust system, are the cats really necessary?? I live in New York so the cats are not mandatory.

What do you guys recommend??

Thank you!!

[opethmike]

No way there is a 40 HP gain from going cat-less.

[TTait]

You will notice a performance boost without the cat - I ran a hollow cat for more than a year until I had to get smogged again.

[DeLorean03]

I dont have a cat on mine, and there's no way I am getting 170 HP. Maybe 140-145 at most.

[WelmoedJ]

Removing a cat gets you an additional 12 HP at the most.
The 160 HP power is only found in European versions of the PRV.
The US version, without cat will reach about 140-142.

Mind that these figures only refer to SAE (crank) HP, not wheel HP!

Dyno (wheel) figures go from some 90 (auto) to some 110 (manual) for our standard DeLorean engine.

[DMC3165]

Hi all,

I rememebr reading, without the catalytic converters the Delorean has around 170HP. Sound right??

I am in the processs of changing the whole exhaust system, are the cats really necessary?? I live in New York so the cats are not mandatory.

What do you guys recommend??

Thank you!!

Where we live any vehicle that's 25 years old or order doesn't have to pass emissions anymore (but you already know that). I think our motors can be set up to produce 170 HP but not with stock settings (timing, fuel pres, maybe cams not sure). My exhaust is bone stock with Cats. It's still in good shape so I'm leaving it until I need to do something. I'll probably go with a stage 1 from DMCH or a Hervey setup. I'll see when the time is right.

[TTait]

Where we live any vehicle that's 25 years old or order doesn't have to pass emissions anymore

Not in California I'm afraid. We have to pass every 2 years and before we can sell it...

Any car after 1977 has to pass here, and that date is no longer rolling, it sticks...

I enjoyed not having a cat for a while - the gain was similar to what I have now with Stegers cams. If the cat wasn't so hard to bolt up to the muffler I would probably swapped my hollow cat back on and only installed it for the smog tests.

[content22207]

... I think our motors can be set up to produce 170 HP but not with stock settings (timing, fuel pres, maybe cams not sure).....

Not unless you're planning to replace the pistons too -- Euro PRV's are 9.5:1 compression. Fueling is commensurately different as well (you could probably create a reasonable facsimile by running the frequency valve open loop). Euro CPR's have the same final control pressure as North American units, but they start lower and take longer to get there (with no Lambda to contend with, they run rich the whole time manifold pressure is down). Richer overall fuel metering allows a slightly more aggressive spark advance curve (base timing is actually retarded from North American spec: 10 degrees BTDC).


Bill Robertson
#5939

[A Van]

152hp at the flywheel, 119hp at the wheels, stock fuelling with UK performance exhaust.

We have a few guys who have fitted the Euro fuelling with DeLorean engine, one guy with such a set up and a UK exhaust, got 158 and 124 respectively.

[DMC3165]

I don't want to misquote anybody but someone should ask Justin Mettee about his car. I think he said he's making about 190 HP on a stock bottom end. I don't remember what's been done to it aside from cams and exhaust.