Performance Upgrades

[scrasm]

I want to thank you for being helpful in the purchase of my all original '81. OK, now do you have suggestions as to where to start to add horsepower? I have read exhaust system is a good place to start, but any other minor altercations without changing the motor and breaking the bank?

Steve

 

[Hib Halverson]

Two good places to start:
1) Goals. How do you want the car to perform when your modification project is complete?
2) Cost. What is your budget for modifications?

 

[simbadb]

I want to thank you for being helpful in the purchase of my all original '81. OK, now do you have suggestions as to where to start to add horsepower? I have read exhaust system is a good place to start, but any other minor altercations without changing the motor and breaking the bank?

Steve

As Hib Halverson is already aware. I went with: Flowmaster, SLP Cold-Air Intake and Hypertech Tune. I know a Hypertech tune can not be done on your 81 but I would think the exhaust mods and Intake mods would prove a good start and are not too expensive.

 

[Sensei]

The exhaust is the biggie. I replaced my exhaust and FELT a HUGE difference (shorty headers, 2.5" true duals w/ no cats and high flow mufflers). A couple of years after that I rebuilt the engine with Dart heads, Flat top pistons, Edelbrock intake and a Comp cam. With all of that, I did not feel as big a difference as I did with the exhaust alone. God bless, Sensei

 

[scrasm]

Two good places to start:
1) Goals. How do you want the car to perform when your modification project is complete?
2) Cost. What is your budget for modifications?

I don't want it to be a race car, but I would like another 100 hp. I would like to spend a couple thousand a year for the next few years improving the car. A piece by piece process over the next couple of years would be fine.

Steve

 

[simbadb]

I don't want it to be a race car, but I would like another 100 hp. I would like to spend a couple thousand a year for the next few years improving the car. A piece by piece process over the next couple of years would be fine.

Steve

Not a race car; then remember "Diminishing returns" For $2500 - $5000 (Total) you will be able to accomplish %90 of the performance improvements you seek. The temptation is always to just do that "One last thing"..."Well I already have that dismantled, why dont I just do this now" Have to resist that one, or you will be looking at a $30,000 C3.

 

[minifridge1138]

I don't own an '81, but I have tinkered a bit with my 1982.
I've sort of ordered these based on ease/price. And these are just ideas.

1) Complete tune up. It almost sounds too easy to be true. Replace spark plugs, plug cables, cap, rotor, worn hoses, fluids, brake pads, rotate/balance tires, clean the carburetor (1981 may need different cleaning procedure), and lubricate the grease fittings. This won't result improved dyno numbers, but you'll be amazed how much better the car will drive with some new parts.
2) Exhaust is a great place to start. The only thing you may have to worry about would be an emissions test. If you want to go all out, start at the headers and work your way to the tail pipe. What i love about this, is you aren't really increasing the power out of your motor, you're just getting the hidden power that is already there. Headers + Mufflers will be around $500. I've seen improvements ranging from 3hp to 30 hp.
3) Intake. Now that you have no problem getting the exhaust out of the car, it is time to improve the air coming in. K&N Filters are a good start. They'll last forever and can help a bit. Intake manifold (i know 1981 is a bit different than other years, but i'm sure people here can suggest a suitable manifold). $50 for K&N filter. $200 for an Edlebrock or Holley intake. $?? for 1981 carb.
5) Camshaft / rocker arms. This is a combination of intake and exhaust. More aggressive cam+rockers will increase the amount of air/fuel coming in and exhaust going out. I've known quite a few people that replace the camshaft as their only project. They get quite a difference and the engine looks all original. Roughly $400. Most cams are about $200 and so is a set of rocker arms.
4) You now have air coming in and exhaust coming out. Time to improve cumbustion. Heads are the easiest way to do that. And often, heads will offer the best power-to-dollar ratio of any project. New pistons can also help with that.
5) Rear Differential. This will add zero power to the engine, but it will get the power to the wheels a lot faster. 1982 came with 2.7:1 gears. (i'd bet 1981 was not too different). The downside to this is your gas mileage will suffer. 1982 was a different transmission, but with 2.7:1 gears I run at 1800 rpms at 70 mph. Moving to 3.55:1 gears would bring me to 2300 rpms. My highway gas mileage would go from 22mpg to 17mpg. This depends on if you want to smoke tires or cruise. This is not a do-it-yourself job. GM used shims to align the ring gear, and it can be a pain to get a new one aligned. This is one i'd probably take to a skilled mechanic.

Those are some of things you can do. They range from cheap and easy (air filter) to things you probably won't do yourself (differential). Every car is different, so what works for me may not work as well for you. Most of these can be done for under $1000 each. (Exhaust and Intake combined would probably be around $1,000 if you do it yourself).

Good luck, enjoy the car, and post some pictures!

 

[scrasm]

Wow, thanks for the info. These are great ideas.

Steve

 

[big2bird]

The single largest thing without breaking the bank, rebuild that tired old diffy, and put in 3.73 gears. $1,000. Then, change the tranny to a 89 700-R. $2,000. This will make it perform better than any other mod, and you won't even touch the engine.
If you do later, it will still help. As Cris stated earlier, start with the exhaust.

 

[GerryLP]

The single largest thing without breaking the bank, rebuild that tired old diffy, and put in 3.73 gears. $1,000. Then, change the tranny to a 89 700-R. $2,000. This will make it perform better than any other mod, and you won't even touch the engine.
If you do later, it will still help. As Cris stated earlier, start with the exhaust.

Big2bird,

Why an 89 700r4?

And are they $1k dollars now?ohnoes:crazy

 

[big2bird]

Big2bird,

Why an 89 700r4?

And are they $1k dollars now?ohnoes:crazy

I have asked TimAT to answer specifically. I know they had alot of changes/improvements by '89.

As for dollars, by the time you buy a GOOD unit outright, shorten the driveshaft, change the crossmember, modify the shifter, change the TV cable and bracket, BUY a T/C, and fluid, yada, yada, your looking at $2,000 to be realistic. No use changing it with crap. Get something that is worth it.

 

[TimAT]

Beginning with the '89 model year, GM improved the lubrication to the rear planetary gears and added larger bearings in that same gearset in the 700R4 and went to a 10 vane pump. Much more durable than earlier models. They added a couple of more things too, but I don't remember what they were. Bottom line, from '89 to I think '92 are the trannys to get if you're swapping or just rebuilding a 700. The later parts ARE direct interchange for the earlier ones. Get a set of hardend rings for the 10 vane front pump and the pump is as good as it gets too.

 

[zachh]

Bowtie Overdrives sells a complete kit to convert everything for a 700r4. To do this, the shifter needs to be modified, new crossmember/ mount, shorten driveshaft, TCC wiring, new cooling lines, TV cable. I did this to my 79, i bought their level 2 700r4, and i love it. The 1st gear is higher so she screams and ots an extremely fast shift.
zachh
www.bowtieoverdrives.com

 

[Peer81]

If you change the exhaust and later you want to change the tranny to a 700R4 remember that the 700 is longer and the original exhaust doesn't fit with a 700!
Also when you change the crossmember for the 700R4 (or take a 82 crossmember) change it to accept a true dual

Groeten Peter

 

[big2bird]

If you change the exhaust and later you want to change the tranny to a 700R4 remember that the 700 is longer and the original exhaust doesn't fit with a 700!
Also when you change the crossmember for the 700R4 (or take a 82 crossmember) change it to accept a true dual

Groeten Peter

Good point. In Kalifornia you must do this.

 

[herron]

I have the Edelbrock performance manifold and matching 4bbl installed on my 81, and it has been a nice addition. Nothing earthshaking, but nice...which is all I was after. I've been thinking about the exhaust, but after rebuilding the power steering, and the rotted bushings on the front end, am just about out of cash for a while, and was considering something simple and inexpensive, like a pair of Targa exhausts to replace the stock mufflers. That something worth doing for $160?

Also (and this is a question for next year's budget :eyerole), would you recommend the 700R4 or the 2004R trannie from Bowtie Overdrives for everyday driving? I'm just looking to improve (smooth out?) the shift...feels like it never gets in the right gear for highway speeds..........

 

[big2bird]

Also (and this is a question for next year's budget :eyerole), would you recommend the 700R4 or the 2004R trannie from Bowtie Overdrives for everyday driving? I'm just looking to improve (smooth out?) the shift...feels like it never gets in the right gear for highway speeds..........

They both have advantages and disadvantages. I went with the 700-R because parts/kits are more common.

 

[Peer81]

If you're thinking about the money...
A 200 will be a lot cheaper to build in then a 700. For the power the L81 has it doesn't make a difference if it's a 200 or 700. You can also keep your original exhaust system.

 

[herron]

If you're thinking about the money...
A 200 will be a lot cheaper to build in then a 700. For the power the L81 has it doesn't make a difference if it's a 200 or 700. You can also keep your original exhaust system.

That's good to know. Thanks. Not looking to do anything but make it a pleasanter driveabout. Didn't buy it for its speed and power....

-----
Any thoughts on those mufflers to replace the stock ones?

 

[herron]

Any thoughts on that muffler question? Is this http://www.ecklers.com/product.asp?pf_id=A4152&dept_id=1329 a good alternative?