I have a 1980 L48 that was totally stock. I have since added a DUI ignition upgrade, new Taylor wires and Delco Rapid fire plugs, an Edelbrock higher flowing air cleaner, and true dual ss ehaust with magnaflow high flow cats and Magnaflow straight through mufflers. I was hoping for some decent improvements in power with these changes, but got nothing more than changing the exhaust tone. My questions are 1. do I have too much air flow and need to re-jet? 2. could the timing need to be adjusted? 3. or am I just expecting too much from subtle changes? I am trying to maximize my power on a budget controlled by 'the boss'. Any tips are greatly appreciated.

:confused:

 

Welcome to forum :D

1) New wires -> No gain unless old wires were completly trashed
2) New air cleaner -> No gain unless old element was dirty as ....
3) New plugs -> No gain unless old were fouled bad
4) New dual exhaust -> should have felt something from that if everthing else was the same it should have given you a HP gain you would notice

Check to see if your timing is about 36 deg at 3000RPM


[Modified by MotorHead, 8:59 PM 10/14/2003]

 

First of all you are bound to have a pretty good running 80 L-48, the things you have done so far, are subtle as you stated. The problem with subtle changes is that they usually don't produce a "seat of the pants" performance increase.
The things that are really important to increasing performance are getting more fuel and more air into the engine, and out of the engine. Your true duals and high flow cats have probably provided your engine with the ability to breathe a little better than a stock L-48. The real problem with your engine is that it has pretty enemic heads and cam. The heads are pretty weak "polution control" heads with 76cc chambers. Your compression is low and the cam is relatively mild. All these things combined don't give you much of a base to gain real noticable power increases with inexpensive and simple bolt ons.
There are three things that are going to give you the most performance increase and are relatively easy to do.
First the cheapest and easiest to do, headers. Dynomax ceramic coated headers are about $230 and should give you enough extra power to feel it in the seat of your pants, my guess and it's just a guess (12-18hp) Doesn't sound like much but your car was rated at 190hp when it new, so that's pretty close to 10%.
Next thing is a new cam, here you have to be careful, the right cam is really something that should be done with extreme care. With the low compression of your engine, you need a cam that accentuate the compression you have and not reduce it. Longer intake duration cams effectively reduce actual compression levels, in a car running 10-1 and iron heads, this isn't all bad, but in your engine it isn't desireable. I don't pretend to know which cam would work best in your engine, I'd leave that to the experts. A cam, lifters and new springs is fairly inexpensive to purchase, the real trouble is the amount disassembly required to install them. It pretty much requires disassembling 50% of the engine to install and you'll run into a lot of "while your at its" while doing the job.
The next thing to consider is a new set of heads, probably the most important and expensive bolt on you can add. A good set of aluminum heads will can cost anywhere from $900 to $1400, but they along with the right cam can produce a gigantic performance improvement. If you are looking for a package check into the Edelbrock Performer and Performer RPM package, of intake, heads and cam. Pretty good performance at a fairly inexpensive price.
I've rambled long enough and probably given you more information than you wanted to hear.
Good luck and welcome to the forum!

 

Thanks for the welcome, I really like this site. I new the plugs and wires would not make much difference, but I thought for sure the dual exhaust would have a noticable difference. I'll check the timing tomorrow. I do notice that the previous owner has a lot of the vaccum line cut and plugged. I also notice a raspy sound from the carb area when I give it the gas. It just seems like its getting a lot of air. I will probably pull the plugs too and see how rich/lean things are running. UH OH, wouldn't you know, I turn my back for a minute and the Marlins just grabbed 8 runs in the 8th! :mad

 

Thanks Smokehouse! This is exactly some of the information I was looking for! Ironically, the Edelbrock RPM performer package is what I was looking to do next. The heads will have to wait awhile. Do you think headers will make that much of a difference? I have been told that vette mani's are the next best thing to true headers.

 

i went with hooker headers, but am going with the dynomax with the new motor going in. 75-82 corvette exhaust and intake manis are no better ones off a silverado or the basic four door, IMHO. you might see a little difference on the dyno,,,,,but you wont see shot on the street

 

In my humble opinion, headers are the best single investment you can make for a noticeable performance improvement. If you figure HP to $. Ram's horn manifolds are just ok manifolds, better than most, but not anything like headers. The stainless steel "shorty" exhaust manifolds that were put on some of the later C-3 and C-4 'vettes, were an improvement over the Ram's horn, but still not a set of true headers.
Just remember the lower base you start with the lower amount of hp you can expect from adding headers. On a high performance crate engine (ZZ-4, etc.) running stock ram's horn manifolds will absolutely choke the performance, and headers will really allow the engine to rip. With a low compression L-48, headers are not going to turn it into a screamer, but you should notice a difference over your stock manifolds.

 

I agree, but a VERY close 2nd, if you can live with reduced MPG-figures, are rear gears.
Most of the mods we make on our cars result in higher power at higher RPMs; if it can't 'wind-up' fast, it'll just sit there and 'lug' itself silly.
I had 3.73s put in my '82 a week ago (waiting to correct a broken speedo-gear now), from the OEM 2.87s, and just a little driving (25 miles?) told me the ol' Cross-Fire will be a whole 'nother animal (or, as much 'animal' as a Cross-Fire 'CAN' be..... :rolleyes: )