Fielding Interest - Trading Stage I Exhaust for Stock System (CA Owner)

[Lwanmtr]

Id offer to trade my stock exhaust, but you'd have come up here and help me take it off... (and put the new one on)..lol

[Ryan King]

UPDATE -

So for now. I bought those aftermarket Catalytic Converters and will try to have them welded up by a local well known shop.

I really thought the idea over for awhile. A lot of what I think "killed my cats" was my Distributor was "tuned" to 18 degrees. This really adds a lot of extra unnecessary stress to the cats. So I have reduced the timing to within spec...about 14 degrees. I have a Stage II with Dons Crazy Cams from DMCCA. I don't really notice much of a performance reduction and I feel like the engine runs better being at 14 degrees. I will see how the numbers look after SMOG.

Aside from getting a stock exhaust, I feel like this the best long term solution available right now.

[Rich]

Really good to see this update, Ryan. I think you're on the right track.

You probably know that one of the Calif. smog test checkpoints is ignition timing. The timing spec is 13deg. BTDC +/-2deg so without adjusting down to 14deg. as you did the car likely would've failed on that criteria before they even sniffed the exhaust. Or did it ever pass smog at 18deg?

And just out of curiosity did you need to run premium (91 octane here) to keep the engine from pinging with that 18deg setting? Am setting aside the effect of the Stage II cams for the purpose of the question.

[vwdmc16]

Agreed, my local inspectors always check that too. I don't know how you can run that much timing and not have detonation, I just bumped my engine back up to 15 degrees which really perks up the responsiveness but I get a bit of pinging if I stab the throttle hard at lower rpms (vacuum advance works quickly), but I always run 87 octane too. Im curious how much more timing I could get away with on 91.

Side note I also have DpI cams and a volvo distributor, also still have my stock exhaust on untill I can dyno it and swap back to my DMCH system for back to back testing.

I'm having to keep my stock exhaust system in a box for 23 months between smog testing, because I cannot find anyone in the area who will visually pass and aftermarket exhaust kit on my car. Also according to the five gas analyzer I have, the DMCH exhaust system burns cleaner than factory.

[David T]

With CA being so strict you may have a hard time passing with those cams. Certainly not having the timing to spec will cause you to fail just as not having the stock exhaust, I don't think the Stage II is an approved part. To find out just exactly what base timing you should set you need to get in touch with DMCCA about their cams. You should probably use the highest octane you can get. If you hear any pinging you are doing damage to the pistons. Too much timing, too fast on the advance or not enough octane. Could also be the motor is running too hot. California is a tough State. Best to stay as stock as you can and you should be able to continue to pass.

[opethmike]

Agreed, my local inspectors always check that too. I don't know how you can run that much timing and not have detonation, I just bumped my engine back up to 15 degrees which really perks up the responsiveness but I get a bit of pinging if I stab the throttle hard at lower rpms (vacuum advance works quickly), but I always run 87 octane too. Im curious how much more timing I could get away with on 91.

Side note I also have DpI cams and a volvo distributor, also still have my stock exhaust on untill I can dyno it and swap back to my DMCH system for back to back testing.

I'm having to keep my stock exhaust system in a box for 23 months between smog testing, because I cannot find anyone in the area who will visually pass and aftermarket exhaust kit on my car. Also according to the five gas analyzer I have, the DMCH exhaust system burns cleaner than factory.

I run DPI cams/heads/exhaust, stock distributor, and EFI. I use 93 octane fuel here in NYS, and I have been running 20 degrees timing with no issue. I idle at 14.0 AFR, cruise around 14.5, and WOT is 13.1 AFR.

[David T]

I run DPI cams/heads/exhaust, stock distributor, and EFI. I use 93 octane fuel here in NYS, and I have been running 20 degrees timing with no issue. I idle at 14.0 AFR, cruise around 14.5, and WOT is 13.1 AFR.

As strict as NYS is, CA is another level stricter. Over there, even if you can pass emissions, if you don't have stock parts, or approved parts, they will still fail you. You may also be doing your timing advance differently too because you are using EFI. Not exactly comparing "apples with apples". The fuel may also be different, more or less Ethanol and other "things" in it. Altitude (Baro) can also be part of it too. Especially if you are using a knock sensor. That will automatically de-tune your timing so you don't ping if you're EFI controls timing.

[opethmike]

As strict as NYS is, CA is another level stricter. Over there, even if you can pass emissions, if you don't have stock parts, or approved parts, they will still fail you. You may also be doing your timing advance differently too because you are using EFI. Not exactly comparing "apples with apples". The fuel may also be different, more or less Ethanol and other "things" in it. Altitude (Baro) can also be part of it too. Especially if you are using a knock sensor. That will automatically de-tune your timing so you don't ping if you're EFI controls timing.

Uh... okay?

I wasn't trying to compare apples to apples, but I guess specifying in detail how I am doing what I am doing doesn't suggest that?

Also, thank you for letting me know how EFI works. I had no idea. It's not like I designed my own setup or anything.

[DKDMC]

Man I have the spec exhaust and headers on my car now. I hope I don't have smog issues next April! this is stressing me out!

[vwdmc16]

I run DPI cams/heads/exhaust, stock distributor, and EFI. I use 93 octane fuel here in NYS, and I have been running 20 degrees timing with no issue. I idle at 14.0 AFR, cruise around 14.5, and WOT is 13.1 AFR.

Efi and 93 octane? Lucky guy! Apparently we can't be trusted with an extra two octane points here in California.

Have any horsepower numbers? I'd love to know