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I've a Sliver anniversary L48. My exhaust (below the axle) keeps catching on the bumpy roads we have around here.
A '78 car is not required to have smog equipment in the UK.
Lovely car to drive, but an L48 won't pull the skin off a rice puddling.
I liked Hot Wheels cars as a kid.
THE SOLUTION to all this maybe to fit Doug's headers and side pipes! What do you reckon? Do they look cool (ceramic or chrome?), will they make more power? Any other tweaks to wring a bit more power, bigger jets perhaps if the motor's breathing better?
Side pipes look cool. The power difference is minimal. In fact more power can be had with exhaust out the back depending upon the design of each.
Also, if bumpy roads is your issue, side pipes won't fix that either. If anything they are lower, again depending upon the headers you have now.
Go with sidepipes if you want the look and sound. Go with out the back if you want power and a bit quieter exhaust. Clearance is close and debatable either way.
tech. speaking exhaust out the back gives you better performance,
because you have room to build a system. with many muffler/ exhaust possibilities.
but nothing beats side exhaust for cool factor !
I've a Sliver anniversary L48. My exhaust (below the axle) keeps catching on the bumpy roads we have around here.
A '78 car is not required to have smog equipment in the UK.
Lovely car to drive, but an L48 won't pull the skin off a rice puddling.
I liked Hot Wheels cars as a kid.
THE SOLUTION to all this maybe to fit Doug's headers and side pipes! What do you reckon? Do they look cool (ceramic or chrome?), will they make more power? Any other tweaks to wring a bit more power, bigger jets perhaps if the motor's breathing better?
Any help or advice please?
I actually have Doug's ceramic coated side pipes on my car. My engine is modified now (Aluminum heads, cam, intake), but when I first installed the side pipes and headers, my engine was stock.
A couple tips. Side pipes need baffles otherwise they are essentially just a straight pipe (RIDICULOUSLY loud). A lot of the misconception about the power sidepipes make is due to the different baffles. Most of the baffles on the market SUCK for power. They may quiet the side pipes down, but they do it by restricting too much airflow. The answer is to buy the STS baffles. There's a guy on the forum here who makes and sells them. I have them in my side pipes and they are fantastic. No power loss that I can tell from running straight side pipes to running side pipes with STS baffles. So if you like the look of side pipes, get the Doug's ceramic coated and the STS baffles. You'll gain some horsepower if you have a stock exhaust and it will sound much better as well.
Also, make sure you rejet your carburetor correctly after installing the side pipes (use an 02 sensor or learn to read plugs) and RECURVE YOUR DISTRIBUTOR! If you do those, it will somewhat wake your L48 up.
If that's not enough, it's time for some small chamber heads to raise compression, a bigger cam, and a nice dual plane intake. I did that on mine and it is a totally different beast. Shreds tires and throws me back in the seat when I get on it.
Not all sidepipes are built the same but most follow a common pattern. The fact is, sidepipes may not decrease clearance but could actually increase it. My sidepipes, Hooker stainless steel, increased my clearance compared to the lth's that I removed. The lowest part of my sidepipes system is even with the bottom of my oil pan. My old header collectors were below the bottom of the oil pan and the exhaust pipes under the rear spring were even lower. My sidepipes make good power but they have max flow inserts.
Not all sidepipes are built the same but most follow a common pattern. The fact is, sidepipes may not decrease clearance but could actually increase it. My sidepipes, Hooker stainless steel, increased my clearance compared to the lth's that I removed. The lowest part of my sidepipes system is even with the bottom of my oil pan. My old header collectors were below the bottom of the oil pan and the exhaust pipes under the rear spring were even lower. My sidepipes make good power but they have max flow inserts.
Agreed. My Doug's are almost exactly even with the bottom of my oil pan.
I think instead of blaming the exhaust for your problem start looking at your suspension. If you have a steel spring install a composite spring. Replace all your shocks with Bilstein HD.
Like some have mentioned already, my sidepipes are not the lowest point on the car. Also, side pipes can most definitely improve performance.
I ended up having to go up 2 jet sizes on my '71 stock engine when I installed the side pipes. Your results may vary but most likely some change will be required. I do not have any baffles or mufflers in my pipes.
A few further points:
It's currently all stock, exhaust manifold to tips, as it left the factory. So I'm sure there most be some power improvement, as I'll be dispensing the cat converter and won't be trying to cram everything down one pipe.
In the cold, wet north of England, I think we have different bumpy roads to you. A lot of roads have a lot of crown, to let the water run off, and we get a lot of dips in the wheel tracks. I take your point about a composite spring and HD shocks, but the ride height looks OK, and the ride is reasonably firm. If there's a problem, it's probably the exhaust is saggin, but at best, it could only be about 3/4 " higher.
Mobird, thanks for your comments, a couple of questions if I may lease:
Is Doug's ceramic coating a nice durable, mark-resisting finish?
I can get the whole Doug's thing as a complete kit here in the UK, I'm trying to find out what the muffler/baffles inserts are...
I can read plugs a little, but what jets would you recommend to get me going? ...1 or 2 sizes?
Thanks you guys, this is really helpful, thanks for helping a newby numpty in a foreign land! It's a tricky habit to pursue over here!
I think I've seen a distributor advance kit on Summit's site, would that sort me out?
I have side pipes and I can not imagine that a properly installed under car exhaust would hang lower than the side pipes. How about some pictures of your car showing the ride height and the installation of the exhaust in the rear area of the car.
I have side pipes and I can not imagine that a properly installed under car exhaust would hang lower than the side pipes. How about some pictures of your car showing the ride height and the installation of the exhaust in the rear area of the car.
A bit tricky, the cars in storage, but I'll see what photos I've got...
Mobird, thanks for your comments, a couple of questions if I may lease:
Is Doug's ceramic coating a nice durable, mark-resisting finish?
I can get the whole Doug's thing as a complete kit here in the UK, I'm trying to find out what the muffler/baffles inserts are...
I can read plugs a little, but what jets would you recommend to get me going? ...1 or 2 sizes?
Thanks you guys, this is really helpful, thanks for helping a newby numpty in a foreign land! It's a tricky habit to pursue over here!
I think I've seen a distributor advance kit on Summit's site, would that sort me out?
The finish is durable as far as rock chips and anything you would normally experience on the road. However mine has a few scratches in it from installation. Haven't tried to see if they would polish out, but it's well worth it in my opinion as the side pipes cool off pretty darn quick.
Your best bet on carb jetting is to get a Wideband o2 sensor setup (think you can get the AEM one for about $150). I'm assuming you are running the stock Quadrajet carb? If so, your main jets may be fine, but your secondary rods might need to be adjusted or vice versa and it's really hard to say which when you can't monitor the A/F ratio at different RPMs. Seriously, the wideband 02 was the best tuning purchase I've made for my car.
Seriously, the wideband 02 was the best tuning purchase I've made for my car.
X 100! Plugs are harder to read these days because of the newer gasoline formulations, so I've read. An afr gauge is far better than reading plugs. When your afr is dialed in, then go read your plugs.
I have side pipes and I can not imagine that a properly installed under car exhaust would hang lower than the side pipes. How about some pictures of your car showing the ride height and the installation of the exhaust in the rear area of the car.
I found these photos:
-not got any shots looking under the back, but I wouldn't say it's on it's *** -would you?
Your best bet on carb jetting is to get a Wideband o2 sensor setup (think you can get the AEM one for about $150). I'm assuming you are running the stock Quadrajet carb? If so, your main jets may be fine, but your secondary rods might need to be adjusted or vice versa and it's really hard to say which when you can't monitor the A/F ratio at different RPMs. Seriously, the wideband 02 was the best tuning purchase I've made for my car.
Oh NOOOO! Added layers of complexity I can't deal with!
The guy with the Doug's here in the UK offers them with these:
Max Flow Mufflers (best power and sound)
Reverse flow mufflers (quieter than max flow)
Glass pack balances power and sound
The STS baffles, I've found lots of informed and researched opinions all pointing to STS. But with the weak £, shipping, duty etc they will probably be about $600 by the time I get them, is it going to be worth it? I would like to notice more power (surely dumping the cat and 2 pipes will help?), and I don't want the noise to be a drag on a journey (my wife owns 1/2 the car!).
As for the wideband O2, I reckon it's still the stock carb -although not yet checked - but I'd rather not be getting into that, I'd have to put a hole in the sidepipes for the sensor presumably, I'd rather just go one (or two?) sizes up and be in the ball pack rather than chase down the last 5hp.
But I'm very grateful for your advice. If you think I MUST do the above, in spite of cost and hassle, do tell me!
ride height looks fine but in that last picture I seem to see a lot of the muffler leading me to believe the exhaust is sagging. If you go with the side pipes get them with the glass packs, your ears and the neighbors will appreciate it.
If youre expecting to really feel the power youd want vs $ spent and the noise dont do the sidepipes. Coatings will scratch up easy
If it were me ditch the cats, do a true dual 2.5" exh get some mufflers you like dont worry about the H X etc dont even need it esp on a stock vehicle.
Exnaust like that should not cost much if you have a shop nearby they can fab one up and tuck it tight where it wont cause heat problems.
If you want to kick it up a notch then get some headers not a big deal to cut it and fit it up to them. It will sound maybe even feel a little better without annoying the wife. Yes the coatings scratch easy
Thanks for further 'sound' advice cuisinartvette (haha pardon the pun). Favourite as of this moment in time, is to get rid of the cat, have a genuine 2 pipes and clamp the exhaust up to the IRS. Or get a new wife. Or maybe both. But no doubt I'll be back to change my mind about some of the above!
I currently have side pipes on my 79 and i love the look and sound! some things to consider though you WILL smell the exhaust especially while sitting in traffic and on my car they are the lowest point of the car, about 4" off the ground. I always have to be weary of speed bumps and driveways! usually i take them on at an angle to clear them.
03-01-2017, 09:32 AM
Side pipes for looks and power?
X 100! Plugs are harder to read these days because of the newer gasoline formulations, so I've read. An afr gauge is far better than reading plugs. When your afr is dialed in, then go read your plugs.
