Exhaust / CAT question.

[Ras12]

Has anyone ran their stock PRV with no CATs? As a registered antique vehicle I only need to meet safety standards and not emissions (sorry). I have a leaky EM gasket and was considering installing headers and a magnaflow exhaust and wanted to know if there were ant advantages or disadvantages?

Thanks

[pezzonovante88]

Has anyone ran their stock PRV with no CATs? As a registered antique vehicle I only need to meet safety standards and not emissions (sorry). I have a leaky EM gasket and was considering installing headers and a magnaflow exhaust and wanted to know if there were ant advantages or disadvantages?

Thanks

I ran with no cat. When I got the car, the car was so old that it essentially gutted. I then had it removed and had custom cat-back exhaust system installed.

[David T]

I ran with no cat. When I got the car, the car was so old that it essentially gutted. I then had it removed and had custom cat-back exhaust system installed.

It is mostly dependent on the laws in your State. In many (not all) States after so many years they no longer test emissions or if you drive less than a certain # of miles. Some States do look to see if the cat is still there so there is something to be said for keeping the cat and gutting it. You also have to consider the consequences if you sell the car and what the new owner will have to do and what State he will be in (or not). The cat does reduce the exhaust noise kind of like a pre-muffler so the motor will sound louder. Doing headers and a less restrictive exhaust will help the motor breath better but don't expect much additional performance without making other changes like cams, improving the intake side and the fuel system. For what you can spend you do not get a lot if you only do the exhaust. The first iteration of the Island Turbo did not have cats and it was noisy. The next iteration added cats and it was quieter. A loud exhaust may sound impressive but after a long drive it gets tiring. My advice is to just replace the exhaust gaskets (and whatever else you break in the process). BTW in most States the PRV runs so clean it will pass the 81, 82, 83 year standards without a cat as long as they don't look for it and the engine is in good tune.

[chris williams]

It's very common to de-cat DeLoreans over in the UK where emission rules are not that strict on early 80's cars. Never really caused any issues and frees up a couple of HP! However getting hold of the de-cat pipe seems to be more of an issue.
Chris

[Delorean Industries]

I know a guy.

[chris williams]

I know a guy.
;) I had seen your posting on on your new slimmer ones do you do de-cat pipes as well?
Chris

[5875]

I ran with no cat. When I got the car, the car was so old that it essentially gutted. I then had it removed and had custom cat-back exhaust system installed.

New owner of 5875...

I like what the PO did with the exhaust...it's more my wife that doesn't appreciate the extra "car smells" in our garage! I've visited with a fellow local DeLorean owner who still has the stock exhaust system versus mine without the cat and muffler and I do find my exhust smells a lot more. That being said, I have a few extra HP to compensate. This summer I will likely add a muffler to the system as I find it a touch too loud for my liking. Case and point, I brought mine for regular servicing to a locally respected classic car garage and the owner mentioned on start-up that it sounded like their was "an exhaust leak" - not exactly the sound I'm aiming for!

[Delorean Industries]

;) I had seen your posting on on your new slimmer ones do you do de-cat pipes as well?
Chris

Yes. Right here:
http://www.deloreanindustries.com/test-pipe-kit/

Dropped the shop I phone in a vat of coolant.... Isn't exactly taking calls right now. Feel free to email me with any further questions.

[Gary]

Washington state doesn't require cars over 30 years old to have emissions. So I had a delete pipe made for my stock exhaust system. I cant really tell if it improved anything. The exhaust note isn't much different. I was surprised however that it didn't smell like gas when I pulled out of my garage! If your cat is good (not plugged) I probably wouldn't go through the extra expense unless you were upgrading the entire system.

[5875]

Speaking of exhaust systems...has anyone installed Hervey’s kit on a stock engine? I like the idea of getting rid of the passenger side cross-over and just going straight out, but taking a look on that side of the engine bay, there’s the battery wire and alternator. My concern is that there’s not enough room to fit that passenger side muffler in there, and even if there is, the heat will melt the components. A few questions:
1- Anyone have success with this install?
2- Did you need to use additional heat shields on the right-hand side?
3- Will I have to modify the alternator set-up to fit the right-hand side muffler?
4- Did you bother hooking in the Lamda sensor? (if not, how did you turn off the warning light)
5- How does the system sound?

Cheers

[Nicholas R]

Dropped the shop I phone in a vat of coolant.... Isn't exactly taking calls right now. Feel free to email me with any further questions.

Haha! I literally did the exact same thing to my first iPhone back in 2012. Fell in a 5 gallon bucket of old coolant and for a second I just stared at it until it clicked what had just happened, haha. It still worked afterward with the exception of the earpiece speaker. Pretty much had to make all my phone calls on speaker for the next year

[Delorean Industries]

Very frustrating to say the least. I damage and or destroy a good number of phones in this business. Took way longer than it should have to get a replacement up and going. Not to mention the new phone is running the latest version of IOS.... All of my hard work not letting it update for nothing....

[Victor]

Speaking of exhaust systems...has anyone installed Hervey’s kit on a stock engine? I like the idea of getting rid of the passenger side cross-over and just going straight out, but taking a look on that side of the engine bay, there’s the battery wire and alternator. My concern is that there’s not enough room to fit that passenger side muffler in there, and even if there is, the heat will melt the components. A few questions:
1- Anyone have success with this install?
2- Did you need to use additional heat shields on the right-hand side?
3- Will I have to modify the alternator set-up to fit the right-hand side muffler?
4- Did you bother hooking in the Lamda sensor? (if not, how did you turn off the warning light)
5- How does the system sound?

Cheers

Hi !
I went with Hervey's headers, no cat, and one single muffler (at the very same place as the old one) But one of the header had to be slightly modified to make some room near the alternator. All the tubing are 2'' stainless. I removed the oven of course and put a direct air induction with a K&N air filter. The Lambda light is sometime on, and sometime off.
The car sound a bit more loud though, but only at the start. When cruising, it does not make more noise than any other car.

[David T]

Hi !
I went with Hervey's headers, no cat, and one single muffler (at the very same place as the old one) But one of the header had to be slightly modified to make some room near the alternator. All the tubing are 2'' stainless. I removed the oven of course and put a direct air induction with a K&N air filter. The Lambda light is sometime on, and sometime off.
The car sound a bit more loud though, but only at the start. When cruising, it does not make more noise than any other car.

The Lambda light is only connected to a mileage counter and lights up after a set interval of 30,000 miles. It is turned off by resetting the counter. It is NOT an MIL as on a newer car and does not indicate an error code. It is only a reminder light to have the car serviced. You should have an O2 sensor in the exhaust so the Frequency valve can operate properly in "closed loop".

[5875]

Hi !
I went with Hervey's headers, no cat, and one single muffler (at the very same place as the old one) But one of the header had to be slightly modified to make some room near the alternator. All the tubing are 2'' stainless. I removed the oven of course and put a direct air induction with a K&N air filter. The Lambda light is sometime on, and sometime off.
The car sound a bit more loud though, but only at the start. When cruising, it does not make more noise than any other car.

Thanks Victor. So did you use the stock muffler then?

[Victor]

The Lambda light is only connected to a mileage counter and lights up after a set interval of 30,000 miles. It is turned off by resetting the counter. It is NOT an MIL as on a newer car and does not indicate an error code. It is only a reminder light to have the car serviced. You should have an O2 sensor in the exhaust so the Frequency valve can operate properly in "closed loop".

oh ok. Thank you very much for the info. I thought it was related to the fuel pump functioning. I will try to remember to reset the counter in the spring. I can't wait to springtime now!

[Victor]

Thanks Victor. So did you use the stock muffler then?

no. I used a somewhat smaller exhaust with double in & double out.