Smog Equip Info

[captras]

Does anybody have any idea how much horsepower/performance change I can expect from my 75 L48 with removal/disconnect of the smog pump and/or elimination of the cat and installation of true duals?

 

[photovette]

I don't know the exact number, but when I switched to true dual exhaust on my 1977 L-48, I could really feel a difference. That'd have to be about a 20hp increase I'd think.

The air pump is easy, cut the belt and see if you notice any difference--you won't, it's such a low power drain. My '77 didn't come with A.I.R. from the factory, so I didn't have to yank it out. However, I bought a 1 year old 1981 Corvette in 1983 and the very first thing I did was yank the A.I.R. system--mainly cause it takes up so much room.

 

[brusso]

I did exactly what your asking about. When done, I was able to notice a difference in top end performance. The biggest help was getting rid of the 30lb restrictive cat. Also, don't over pipe your stock 350. Don't go with anything over 2 1/4" pipes unless you plan on doing some serious mods to put out over 400 hp or so. Don't know for sure, but it has been said that going to an off road type exhaust(no cat duels) alone will give you 20-30 more hp. So with those changes plus some minor timing and fuel richening techniques you can get that stock 165 hp up to about 195-200.

 

[captras]

Thanks for the info

 

[like2drive]

I recently moved to NC from SC where there were no emissions testing or inspections. I've been working on the 81 for over a week in hopes of passing the required inspection that mandates that all original equipemnt must be on the car, eg...smog pump, air tubes, cat, vac hoses, etc. When I finished putting all this stuff back on, I could really tell a negative difference .... The main reason I removed it originally was because theres no way my exhaust is cleaner with all this stifling junk. It't be taken off again as soon as I pass and get my sticker. Its worth it to me to spend a week a year swapping parts to get to drive a purring vette. Incidentially, currently I'm stuck on repairing my handbrakes!! a safety requirement.

 

[mike weyman]

like to drive,what part of the e brake are you having fun with.if it is the plate that the brake lever tilts on at the wheel, i have an easy fix, just let me know. mike

 

[like2drive]

Thanks Mike, but it's one of those repairs that just keeps expanding! After studing the repair manuals, I knew that I had to get to the shoe brakes that function with the hand brake. First thing, though, is drilling out the factory rivets that hold the disc onto the spindle (the shoes are behind the spindle). I messed up the first disc by drilling too big of a hole before I got the darn rivets out. Then I found that the real problem was that the adjusting screws for the shoes were froze, a spring was broken, and each rear unit had a bad clip. So, being that RIKs, (a local corvette supply, 40 miles, 1 way) was the quickest source for the hardware package, I drove there this morning to get this job done. I didn't get new shoes because my old shoes were not worn.
However, when I got back, in preparing to re-install, I sanded the crystlalized glaze and cleaned the inside of the disc as well as the old shoes. on the last shoe, I found it had small cracks across the rivets at 2 places. Advance Auto said they would have me some new shoes tommorrow. I hate safety and emission inspections!! I'll be lucky to have it back together by Sunday when I go to church. (I need to go!!...this mess puts me in a bad mood).....I suspect the sermon will be something along worshiping false gods....yeah, or wasting the talents god gave me, yeah, ....or God works in mysterious ways....oh..yeah. you know, I just like2drive.