Bolt on performance

[Lugnutz]

What have some of guys done to improve performance (while maintaining the reliability) of your Buicks? More, cleaner air. Ignition options? Spark plugs?

Any other tips appreciated.

Thanks,

 

[The Roadagon]

A good set of headers and a free flowing exhaust system should improve performance a good amount,when tuned properly it will improve engine efficiency therefore fuel economy. Also a good high perf. air filter with
cold air or ram air will help. Having the computer tuned will also impove perf and sometimes fuel economy. If you make all the changes above and do them properly,your will definately feel seat of the pants perf.gains. I run
an electric water pump which is supposed to give you a few extra HP,to date I have had no reliability issues with it,however some may say they are
unreliable. ed

 

[MrBuick (Magnum)]

Quite a few things. 😀


What year is it? EDIT: Ok it's a 95 sedan. Sweet deal. I know a thing or two about 95 Roadmaster Sedans. (Ha, all 5 of my Roadmasters have been 95 Sedans.)

I'll add some stuff later tonight when I get my work done. 🙂

 

[The Roadagon]

Quite a few things. 😀


What year is it? EDIT: Ok it's a 95 sedan. Sweet deal. I know a thing or two about 95 Roadmaster Sedans. (Ha, all 5 of my Roadmasters have been 95 Sedans.)

I'll add some stuff later tonight when I get my work done. 🙂

Cory, Ok, I hope you were planning to go public and not PM
Lugnutz,because you know, we all want to hear what you have to say. I
just gave LN general data that would help anything from a milk truck to a
new Corvette! So if you found some more horsepower in the old LT1 ,
then we all want to know. ed😉

 

[Lugnutz]

Cory..................not that it matters but my new toy is a RMW.....I screwed up on my acronyms and called it a RMS.........so wagon not sedan!!!

But I think it's the same engine!!😀

 

[The Roadagon]

Cory..................not that it matters but my new toy is a RMW.....I screwed up on my acronyms and called it a RMS.........so wagon not sedan!!!

But I think it's the same engine!!😀

LN; As far as I am aware,yes, the wagon and the sedan LT-1 engines are the same.

 

[MrBuick (Magnum)]

For a 94-96, this is the basic bolt on formula I follow.

1. Make sure everything is up to snuff, before adding performance items. Extensive tune up and check. Plugs, wires, fuel filter, PCV valve, O2 sensors, clean MAF/TB, check intake gasket, brakes, trans drain and fill, axle drain and fill, etc.
2. Make sure everything is in well working order, damn it!!

(Ok, that was just a warm up) 😀

1. Cold Air Intake.
2. Catback / Muffler swap.
3. PCM tune(mail order tune)
4. Valve Springs (Valvesprings alone, make a huge improvement)
5. Headers
6. 1.6 Roller Rockers
7. Transmission shift kit
8. Lower gear ratio in the axle / posi traction
9. High stall torque converter
10. Bigger MAF sensor(Stock F-body MAF) & Bigger TB (Note that both of these require a PCM tune for them to work correctly, and in the case of the TB, not burn the tranny up!)

11. Bigger cam shaft
12. Heads & Cam package.

That just covers the go fast part. That doesn't include the need for replacement lower rear control arms to get this power to the ground, better tires to help hook up off the line, or a better suspension if your sedan has the crap FE1 "Water Bed". It also doesn't cover anything like Nitrous, Super Chargers, or Turbo Chargers. To me, any of the 3 is cheating, when you are already working with a decent displacement V8. But I can't deny the impressiveness of these Turbo 4 bangers, and a V6's. Boost on an LT1 normally means big bucks, and lots of headaches. You can have a very fast car without them. It still takes lots of money and time.

There is no right order to follow, but I do feel that the Big 3 you should do first, are a CAI, Catback, and PCM tune. I also feel so strongly about performance valvesprings, that I would highly consider doing them before a PCM tune. I did on my cars. The stock valve springs have a tendency to create "valve float". Most agree it will happen above 5000 RPM, but I feel on most engines, it is happening MUCH sooner than that. You really don't even need that many miles on an engine, for them to be tired. On my 94 Fleetwood, and 95 Red RMS beater, valve springs alone made a huge improvement on how the engine felt above 4000 RPM.

From #3-#10, you can pretty much do it in whatever order you feel helps your wants the best. If changing the gears wasn't so expensive, I would put it much lower on the list. For shaving time at the drag strip, a high stall is by far the best bang for buck. A bigger cam doesn't give a huge improvement, until it has some support from other bolt-ons.

 

[MrBuick (Magnum)]

1 & 2. The CAI & catback are pretty self explanatory first mods. More air in, more air out, less restriction in doing so. By far, the biggest issue with the stock catback, is the factory mufflers. Replace them with a performance set, and you easily have 75% or more, of the stock restriction in the catback. The CAI, the stock air box opening is not large enough, and the "first base" chamber causes turbulence. The "Home Plate" chamber is really not a restriction, but just gets in the way.

3. The PCM tune does more for the car than just helping power. It does, since the Air/Fuel ratio is adjusted, along with the timing tables. The stock downshifts are plain lazy and conservative, for one. If takes way to long for it to realize you want a downshift, and won't down shift when you still have some RPM left in the next lowest gear. The upshift RPM can also be raised for WOT, and part throttle. Every LT1 car has 2 shift pattern tables. For both up/down shift point, and commanded line pressure. There is the normal table, and then a slightly more aggressive table. The Camaro's were always in this aggressive mode. The Firebirds had a button to take advantage of it. It can be wired up to work for any 94-97 LT1.(yes, 97. They still used the LT1 in the F-body in 97) The stock "Aggressive" tables, are hardly worth the effort. But it's worth knowing if you wanted a separate set of tables for the drag strip, or for towing. The commanded line pressure can be raised, which makes part throttle, and WOT shifts feel firmer. It's enough, that my bone stock 94 9C1 could get a 1-2 tire scratch when it was cold, and on crappy tires. There is much more to it. Removal of the rear O2 sensors on 96's, removal of the VATS system, EGR, AIR pump, any trouble code, adjust the speed-o for different tire height/ gear change. The PCM on the 94-96 LT1, controls a LOT.

4. A quality set of budget valve springs can be had for around $100-$200. They are not hard to swap, but it is time consuming, and labor intensive. You can change them without removing the head, or using compressed air to hold the valves up. They will rest on the piston when it is at TDC. I had never changed a set of valve springs on a head OFF an engine, and I did them on my 94 Fleetwood. Took me around 4 hours. Swap the valve springs, and you can bump the shift RPM up. Which is one reason to do them before a PCM tune.

5. Headers are normally a big under taking. They can cost a friggin ton and nearly install on their own. Cost very little, but may require clearancing / mods to the car. Or bolt right to factory cat pipes, and have draw backs of their own due to design, or availability. I have used the expensive long tube / Tri-y's, and the cheaper long tube/mid tube headers. There is no right way to do it. But I do feel that shorty headers are the wrong way to do it. 😀

6. 1.6 roller rockers are extremely easy to install. Remove the nut holding the old rockers on, put the new ones on, and tighten them down to zero lash. Then fire the engine up, and adjust the lash on each rocker. Well, it seems extremely easy to me, since I was born a gear head. 1.6 roller rockers are like doing a mild cam swap. They add to the duration, and lift. They MUST be done after valvesprings, or at the same time. Putting 1.6 rockers on the stock valvesprings, will only make the valve float issues worse. The 1.6 roller rockers help in rwo ways. The increased ratio has more output on the valve side, forthe same exact imput on the cam side. Meaning it opens the valves farther, and for longer. If you use full roller rockers, you also have a reduction in friction loses. It's interesting to note, that dyno test on an LT1 have shown that the powerband will start about 300 RPM sooner, and contine about 300 RPM longer, using 1.6 roller rockers vs stock stamped 1.5's. I did 1.6 roller rockers a few months after valvesprings, and was impressed that you could feel the improvement of them alone.

7. Doesn't really do much for performance, but it's something that one should really consider doing. A 4L60E with a proper shift kit, will last longer. Shifts faster, and firmer, which is a good thing for the tranny. Plus, it's fun to chirp the tires on the 1-2 shift. Don't ever use a shift kit, WITH a commanded line pressure increase in the PCM. Shifts while moving at idle will become so hard it makes you cringe. I put a replacement trans in my 96 Caprice 9C1, that had a very aggressive shift kit. Aparently the PCM had the tables bumped up, which I didn't know. The trans coming out of the 96 9C1, had a shift kit as well... But I forgot it had a vacuum modulator, so the PCM didn't control line pressure. I later put that trans in my 95 RMS "Jesus". Stock PCM it was great. Mail order tuned PCM that had the trans tables bumped up... made me cringe again. I can tolerate a lot, and both times the 3400 rpm high stall converter was soaking up some of the harshness.

8. Lower gear ratio in the axle. The stock gear ratios were 2.56, & 2.93. 2.56 was standard, and 2.93 was optional. It came only with the towing package, or livery option(limo & hearse). Even then, 2.93 is still not enough for these boats. It's decent for highway mileage, but 3.08 is still great on the highway, and it was used on the 94-96 Impala SS / LT1 Caprice 9C1. 94-96 L99 Caprice 9C1's, had 3.23's. 93 and older cars, used 3.08 in the towing package sedans, and 3.23 in the towing package wagons. Many of the 9C1's had 3.42's. This is all worth knowing for junkyard hunting, since the axles will swap. Just keep in mine you really only want to swap a sedan axle in to a sedan, and a wagon axle into a wagon. Has to do with the overall width, and the spacing of the lower control arms. They can be forced, but it's a poor idea to me. If you want to spend the money on a new gear set, and the labor to install it, 3.73's/4.10's are a riot. They make the car feel much lighter, and more fun to drive. Positraction is also worth talking about. Many of the cars don't have a posi, or if they did, it's worn out. The stock posi's are sort of hit or miss with how long they last. Some are junk before 100k, others have over 200k, and still work strong. If you are swapping in an axle, or having one rebuilt, it is really worth adding a posi. Positraction is where both tires will spin, vs just one.

9. High stall converters make the car very fun to drive. They can make the car seem like more fun than having a manual trans. I didn't believe it when a friend said that, but it's true. I also was told that high stalls are always sloppy, and drive like crap. Not with todays quality high stalls. You just have to use the right converter(brand, and stall speed), and make sure you consider the gear ratio in the axle. A higher stall feels much better paired with a lower gear ratio in the axle. You would never know buffmans car has a 3000 stall converter, just driving around normally. The 3.73 gears really make that possible, as they offer more mechanical advantage at take off. I have noticed even the stock converter feels sloppier in cars with the 2.56 gears, vs ones with 2.93's. With the stock gears(I would consider this 2.93 or 3.08), you can do a high stall, but the stall speed needs to be a bit conservative. Otherwise, you will notice the spongy feeling of the converter. The engine will be revving up, but it will feel like the power is sort of lost before it hits the tires. I did a 3400 Edge stall on the stock 2.93 gears, and it was awful. The PCM objected, and put the car in trans limp mode... taking off in 3rd gear. It also made the drivetrain feel extremely sloppy. However, the exact same converter on a car with 4.10's, felt incredible. That 96 9C1 was an ANIMAL after I put the 3400 stall in it.

10. Bigger MAF & TB. Aftermarket MAF sensors are absolute crap. They just try to fool the PCM(it's smart, and will figure it out after a few trips), or just plain report data erratically. PCM tuners hate them, and I understand why. The F-body's used a slightly larger MAF sensor, which is less of a bottle neck. The bigger MAF is really one of the last mods to do, unless your CAI has the option of a bigger coupler forthe sensor. In which case, I would do them together, and do a PCM tune at the same time. Otherwise, I pair it with the larger TB for the reason of them both needing a PCM tune, and not showing much improvement until a few mods have been done beforehand. The bigger has shown improvements on very close to stock engines on some Dyno's, but I am still not sold on it. Part of that improvement is temporary, due to the engine now running a bit leaner. I still think it should be one of the later engine mods. You can get a stocker rebored to 52mm( stock is 48mm). That is a better option, than an aftermarket 52mm. The aftermarket has 52mm and 58mm units. To use a 58mm one, you need to have the openings ported on the stock intake manifold. Also, most of the aftermarket TB's have issues that need to be dealt with. Most of them don't have the idle bleed hole, and also don't allow the idle air control valve to route air to the idle air passages that run below the intake. The idle air goes in a smaller hole in the front of the intake, and pops out in each intake runner, right before the head. The passage improves the idle. When the air doesn't go through there, it won't idle as well. Most of the after market TB's have to be modded, as this circut is not routed correctly.

 

[MrBuick (Magnum)]

11. & 12. Larger cam shaft. In a drag racers world, the bigger cam doesn't really help the car, until you have done the vast majority of the mods above. I know people have been very disapointed with their times after a cam swap, then saw much larger than normal improvements when swapping to headers, or a high stall converter. I'll get into this later, as I'm tired.

 

[Lugnutz]

Hey Cory................you've certainly covered off a lot!!! Probably more than I'll ever want to do with the wagon.

It already has a new dual exhaust which was put on by previous owner. My next upgrade was air intake, the RAISS system. Upgrade to some 17" wheels off a Caprice.

Thanks for all of the great info. I will refer to this thread and site often.

 

[afaucet1]

very nice thread. I actually just ordered the Pypes street-pro cat back system for a cool $450 including shipping. My exhaust is ridden with holes right now, so it will be a welcome upgrade.

Funny thing is that I never was much of a gearhead until I bought this old boat. It has been a great learning experience these last two years, but I doubt much would have gotten done without the help of this forum. You are an inspiration to us all Corey!

 

[The Roadagon]

If you want a Raiss you better hurry,he is going out of business!!

 

[Lugnutz]

If you want a Raiss you better hurry,he is going out of business!!

Was getting ready to order and found out it won't work for me as my Buick still has the mechanical fan on it!!!

 

[MrBuick (Magnum)]

Buy the RAISS kit, and just remove the mechanical fan. Jesus started life as a towing package car, and it has an SSRI on it right now. The SSRI is extremely similar to the RAISS.