Tuning is one of those subjects that is in the eye of the beholder and can be considered to be an extremely simple subject, or an extremely complex one. It depends upon the experience of the tuner and the depth to which he wishes to pursue the subject as well as what tuning tools he is working with.
Fortunately, modern chip makers have greatly simplified the process IF we purchase a chip that was burnt with our particular combination in mind and our cars SHOULD run well right off the bat with very little tweaking required. Note IF and SHOULD!
Far too often, I see cars that have all the bells and whistles and they don't run well at all. No amount of magic parts will make a car run well that has flaws inherent to the drive train. Yet many will fight taking care of the basics before they try to up the power.
If the engine has low compression on one or more cylinders, if it has a flat cam lobe, burnt valves, worn out timing chain, a turbo that is pushing oil into the engine, weak valve springs, a bad coil pack, module, etc., then you can buy every performance part a vendor will sell you and the car will still be a dog and you will be broke. If the engine is not healthy to begin with, it will only be worse as you start adding boost. If the fuel system will not support the demands of the engine, you will shortly have no engine as you crank it up. If the alternator will not supply the required voltage under load the engine may fall on its face...and so on.
That is the reason we harp on the need for a good scan tool that can record data which in our case is PowerLogger for cars with conventional chips. We also have to monitor fuel pressure and feed that info into PowerLogger as well.
Further, if you have the wrong torque converter, burned out clutches, or a worn out limited slip in the rear, bad shocks, worn out suspension bushings, bad u-joints, engine/tranny mounts, etc., you are wasting your time and money.
Note that I believe a quality converter that is correctly matched to your turbo is the single most important item in achieving consistent, quick times. I try to ignore fan bois and watch what the top guys are running when it comes to a converter. I don't care about how cool a vendor appears to be. I want to see how successful his product is heads up on the track. Yes, it might cost you around a $1000 bucks, but...the way it performs is pay back enuf.
Assuming that one has the patience to build a good platform where everything works as it should with the understanding that our cars are more than 30 years old. All the original stock parts have many cycles on them. There is no sense blowing a head gasket to prove original fuel injectors can hit the 11's You will have to go through your car from top to bottom and be sure everything is right before you can expect it to run up to its potential.
Don't assume that your car will run tens just because you bought ten second parts. There are plenty of 12 second cars out there sporting 10 second parts. There has to be a synergy between parts in order to get the desired performance out of the car. Spend a little time learning the difference between measured performance versus theory, empirical results, opinions, and magazine articles or internet claims. Don't fall for magic numbers or magic parts.
Okay, this is a section titled Tuning and I am ranting about getting basics working right and nothing about tuning. As I stated at the beginning, modern chips made specifically for our combinations should run very well from the start if all else is well in the drive train.
I am not going to delve too deeply into specific tuning as we have a number of options. My opinion is that ten second cars and slower run just as well on a chip as they will on an aftermarket fuel management and there is a lot better chance to keep from blowing something up on a correctly programmed chip made for ones particular combination.
If one is computer savvy and understands the basics of tuning, then I would have no problem in suggesting the ecu-GN aftermarket management system which is offered by Eric Marshall and Bob Bailey which offers many bells and whistles and has added luxury that it can come programmed with defaults tailored for your particular combination so that it will crank and up run well right out of the box. It's based upon the MegaSquirt3 hardware with a custom turbo Buick front end. It's plug and play. It costs nearly a couple of thousand and I don't think it will provide gains for the average guy in the ten second or slower range car, but, if one likes to tinker and put his hands more fully on, it can be fun.
For the new to turbo Buicks owner, I would suggest a chip that is driven by a wide band O2 sensor such as the TurboTweak 6.1. It's kinda hard to screw up unless one just goes nuts with timing or fueling without understanding what he is trying to achieve.
My comments below are directed toward daily drivers that are spraying alcohol for the most part as that seems to be the most common combination. Note that some cars that spray a lot of alky are knocking on the doors of the 8 second quarter-mile so I am not saying I am targeting slow cars.
Now, Tuning in general-What can I change to make my car run up to its potential?
There are really only three things that you can do to alter the tune of the engine assuming you have addressed all the basics.
1. Change the fueling. (Match it to the boost-or vice versa)
2. Change the timing.
3. Change the boost.
If you want the simplest possible answer, run as much boost as you can with as much timing as possible with the leanest air fuel ratio possible without incurring detonation. Note that damaging detonation can occur without you ever hearing it and that is why we must monitor timing retard as the computer has better ears than most of us do.
Having said the above, I will note that cars running on nothing but gasoline are easier to tune that those spraying alky. Cars spraying alky may well require quite a bit more fuel to be pulled out to get them out of the hole in a hurry.
I will also state that cars that are running on E85 are easier to tune that those on pump gas as the A/F ratio is not particularly crucial on E85 but it may not be the best combination for true daily drivers as the conversion is not cheap and fuel mileage is poor.
My Own Basic Assumptions when Tuning
1. I can run less fuel in first and second than I can in third and fourth (don't shift into fourth before the line-hold it in third).
2. I can run more timing in first and second than I can in third and fourth. ( 1&2 are due to the fact that the load on the engine is low due to lower gear ratios in first and second than third and, also, when first pulling to the line the combustion chamber has not had time to heat up a lot. Therefore, one can get away with more timing and a leaner A/F mix without as much danger of detonation at launch (due to the cooler combustion chambers). By the time the car hits third gear, the chamber is hot and one can not get away with as much timing or as lean a mixture as at launch.
3. I can run more timing with small turbos than I can with a large turbo.
4. Race gas is for real race cars. Alky injection is for anything driven regularly on the street if for no other reason than the cost and difficulty in finding leaded race gas..
5. Boost makes more power than small changes of timing-particularly on the street on alky.
6. Due to the lack of change in ambient conditions, I can run closer to the edge consistently at the track than I can on the street so I leave more margin for error on the street.
7. I can run closer to the edge in the 1/8th mile than I can in the 1/4 mile because the combustion chamber does not have the time to build heat and cause detonation.
8. Any amount of timing retard resulting from real detonation will do some damage to your engine and will eventually cost you a lot money as well as slow you down.
Before you start changing things, get a spiral notebook, or a logbook made for such things and write down the particulars of each run-temperature, barometric pressure, humidity, wind direction, wind speed, track condition, etc. as well as the performance details. It's nice to be at a track that gives you info on several waypoints down the track so you can break the run up into segments for analysis. If tuning for the street, write down the particulars and what you have done...also, put some comments in PowerLogger so that the people trying to help you can understand the differences. Be sure you are logging fuel pressure and boost in PowerLogger.
If at the track, make a few runs to dial in your launch technique in order to determine how much boost you can leave at without spinning the tires and how much tire air pressure is optimum. At the beginning, this may take a few tries until you get it figured out. Then it should be a lot easier and quicker.
Finally make two or three runs to obtain some baseline numbers to see if you are running consistently as it is impossible to make decisions on fueling and/or timing parameters if the car does not repeat itself under similar conditions. Remember that changes in air temperature, barometric pressure, humidity, etc. will affect your performance so try to do your tuning when there is not a lot of change going on.
There should not be any timing retard ...but, if there is, LIFT! Reduce the boost or add fuel if it appears to be lean, and try again.
Miles per hour is a better indicator of horsepower than is time as time is affected by launch and track conditions more than miles per hour at the line. At the beginning, concentrate on improving the mph in the lights and then go back and analyze the waypoint information and see if you can tweak the fueling/timing to improve the waypoint numbers-if at the track, of course.
Once you have miles per hour at the finish line optimized and see no other obvious problems such as richness or leanness through out the run, then go back and start trying to find out to improve your short time at the 60' mark.
When it comes to drag racing, it is worth remembering that for each 0.10 second that you can knock off at the 60' mark, you knock approximately 0.15-0.20 off your time to the finish line. How well your car gets thru the first 60' and how consistently it repeats the performance is make or break when it comes to success.
Learning how to launch the car may be the most difficult part of the equation.
Some additional comments that probably go somewhere above.
If you push first and second too much, you will create a lot of heat in the combustion chamber and this may push third gear over the hill so be careful and don't cause detonation in third by going too far in first and second. Tuning is a tedious business and there are no short cuts nor magic numbers.. It is all about what works on your car with its combination and the ambient conditions around it on a given day. That is the reason I like to leave room for a margin of safety. I like living to fight another day instead of fixing what broke because I was too aggressive.
Okay, I have not mentioned timing other than casually. I think most of Eric's chips have defaults of 23 degs in first and second and 21 in third and fourth. That seems to work well on the street in most conditions. At the strip you may get by with adding a couple of degrees more, but, you have to be careful and not make big changes at any one time. Adding timing in first and second can greatly affect the spool up and the launch. If you can stick the tires, it can get you out of the hole quicker...or it can make you break traction. In third gear, I have not seen as much difference and I have seen some awfully quick cars that never used anything but the defaults. Having seen a couple of cars go 10.4 secs in the quarter with timing set at 18 degs in all gears has biased my thoughts on timing-I admit. Too much timing can give you regrets a lot faster than too little. Might note that these cars had the stock factory cam in them as well.
I am not going to mention programming the alky controller other than strongly suggest you start with it set as the manufacturer suggests and read all his notes on tuning the alky flow. Talk to him about changes. I don't normally promote vendors over another but, to my knowledge, Alky Control is the only vendor making Buick specific kits and the suggested settings in the instructions will work as well as possible in most cases without additional tweaking for most cars.
I am going to mention valve springs in this section because it is vital to have an engine that pulls strongly to whatever rpm you require to cross the finish line in third. I used to suggest Comp 980's but they often die after a handful of runs. When they do, the car will not pull in third gear. Now, I suggest quality springs that have a seat pressure of 100-125 psi. Comp 981's seem to be better quality and last longer from various reports than do the 980's we used to suggest all the time. Note, I am talking about flat tappet cams here, not roller cams.
Finally, accept the fact that the quicker you
go, the faster something will break. The corollary to this is, the faster
you go, the more expensive it will be to fix it when it does break. Stuff
happens and none of us are exempt. It's just that it happens a lot faster
to idiots who ignore the warning signals.