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Combination Synergy
It does not matter whether you are building a solid daily driver or a full out track car. Performance will depend upon how well the various parts of the combination work together. Failure to match the individual parts to one another can turn a street driven car into a miserable experience or turn a race car into a poorly performing experience that does not live up to expectations or investment. One major part such as Turbo, Intercooler, or Torque Converter that does not match up with the combo can produce less than desirable results.
As is normal for me, I probably use way too many words to get this point across.
It is probably worth considering that the prices for stock, or near stock, turbo Regals have gone up considerably in recent years for cars in good condition. I am not sure that race cars are worth the money that was put into them in most cases. This may be a factor to consider before heavily modifying one. Just sayin'...
For simplicity's sake, I will assume that the following are the basic parts of the combination.
Air filter/maf/inlet to the turbo. If we go to speed density engine management, the maf disappears and some race cars may not use anything before the turbo to maximize intake flow. Personally, I don't like the oiled type filters as they pass a lot of dirt in a dusty area. I would rather have a dry type paper filter.
Turbocharger There are probably a 1000 turbo options available today...or maybe it is only a 100? Just guessing, but, basically, there are two kinds-Journal bearing and ball bearing. Beyond these two types, there are various housing, portings, etc. to improve performance. The two types may perform the same at wide open throttle once the rpms have come up but they require different stall speed converters to get there and drivability may suffer on a daily driver as a result. For the street, the BB version is hard to beat as one can run a tighter converter and still get a quick spool when opportunity calls. Drivability is better but the BB costs more. On the other hand choosing the correct journal bearing turbo for you car may save you a lot of money and give you excellent drivability. Some work very well without requiring an excessively loose torque converter. Your call. Do your homework.
Intercooler There are two basic types. Stock location or front mount. With a given turbo, the intercooler should provide a minimum pressure drop at a given boost. I would say, ideally, that pressure drop should be less than 1 psi at the maximum boost that will be run with that turbo.
What important is the term "given turbo". A large turbo that is capable of flowing a lot of air will need an intercooler that can receive\pass through this flow without creating excessive back pressure and pass it on to the throttle body.
While this may automatically trigger the thought that a front mount is required, it should be noted that people have gone 9.0 secs in the quarter with a stock location unit. It should also be noted that the major resistance to air flow on a stock location unit is usually in the inlet neck and those people that go very fast have probably spent time enlarging/modifying the inlet neck to reduce flow resistance at that point.
It takes a lot more air flow to go 9.0 sec that it does to run in the tens with a street car so keep that in mind when setting goals no matter what kind of intercooler you choose. In fact, there are a lot more Buicks running in the tens reliably than there are running nines. Be realistic!
Having a stock location unit simplifies coolant cooling in an area where ambient temps are routinely high.
Having digressed, as usual, let me add one more thing about intercoolers. On a drag race car, there is little charge cooling that can occur in ten seconds by air flow across the intercooler core. The intercooler is simply acting as a big heat sink that absorbs heat out of the charge air into the surrounding aluminum and fins. This has been demonstrated more than once by blocking the intake to stock location units so that that no ambient air flow occurs across the core during the run.
This is particularly true on a drag car where the time in operation is so short. What is really important is getting the intercooler cooled off before the next run! Those that monitor air temps before and after the intercooler have demonstrated this repeatedly.
Methanol injection or E85 users have learned what really cools the incoming charge. Still, this heat sink factor provided by the intercooler cannot be totally disregarded.
In conclusion to the above, it is important to remember that on a street car, throttle response depends upon the velocity of the air going into the throttle body and a giant intercooler with a large volume of air inside it will respond more slowly to throttle input so that the car may seem momentarily slow to respond when you press on the gas the gas pedal in traffic. The factory did a great job in balancing components so that the car always felt like there was no delay between foot and rear tires.
Throttle body/plenum When the air comes out of the intercooler it runs into the throttle body. Enlarging the size to the throttle body to 70mm and porting the inlet to the plenum is a substantial increase in potential air flow and requires a 3" hose rather than the stock 2 1/2". In my experience, I have not noticed a significant throttle response difference and it certainly helps to increase potential air flow into the engine. I don't know if anyone is offering modified stock throttle bodies now that Steve Monroe has retired. Running a 70mm unit allows a larger than factor intercooler do its job without creating a serious back pressure problem that may increase charge temperatures.
Cylinder Heads Stock factory heads have no problem running into the 11's. Ported Iron stock heads easily run into the 10's. Faster than that, one might consider a set of aluminum heads with bigger ports than the iron heads. It's all a matter of reducing back pressure so that more cool air can get to the combustion chamber.
Short Block (Camshaft, compression) Some how, we often pull considerable power gains out of engines that have cast cranks and smaller rods than some lawn mower engines. Some seem to get by with the stock block for a long time while others may see the crank break into two pieces while driving 30 mph. Prior abuse probably has a lot to do with it.
Most rebuilt engines go with a minimum of forged pistons and many go ahead and install forged cranks and rods for some insurance. With more extensive mods, one may use a girdle to try to tie the lower end together.
It has been fashionable to allege some magic in the engines that require a magic endowed machine shop. This is largely BS. Any competent machine shop can build a good engine if they have competent machinists and the desire to do so. The one mistake that many shops may make is to open up the clearances like a Chevy engine instead of adhering to factory specs which are much smaller than a Chevy engine.
The reason that this is a problem (large clearances) is due to the Buick oiling system is different from most GM engines with the oil pump being in the front cover rather than in the crankcase. Attempts to use high volume pumps with Buick V8 pump gears bring some problems with them such as oidrain back out of the pump into the pans upon rare occasions and additional strain on the front cam bearing and cam sensor drive and the oil pump drive shaft itself. For a daily driver, I would prefer to minimize this strain.
Having said all the above, these engines can benefit from additional compression along with a bit longer camshaft duration such as something like 210 or so degrees at 0.050" lift. This should increase the operating power band from something like 5000 rpm to 5800 or so. Race cars may take a bit more.
With regard to the compression ratio, many good engines run 9-9.5 CR along with the slightly larger camshaft duration and increased lift. This helps add some power back down in lower rpm ranges and timing is usually reduced somewhat to offset the higher static compression ratios.
You should always talk to some experienced turbo Buick guys and discuss your goals and your budgets before setting course!
Exhaust headers Stock headers can allow the production of pretty high power levels before becoming a bottleneck. The problem is that most factory headers are in bad shape and may be cracked, warped, or otherwise bad and may have been repaired for the last 25 years or more.
Exhaust leaks before the turbo really kill the spool.
Aftermarket headers are available for a price and I suspect many would argue the value received for the price. Some aftermarket headers may have less than the required quality needed to last. Do your research if you go this route before letting go of the money. In fact that is good advice for any mods. Don't buy a car and immediately start pumping money into it until you have spent enough time researching things and have developed a good feeling about the vendors you are considering. There are some really good people out there, but, there are some that never seem to be put out of the business.
Torque Converter In my opinion, this is probably the most important key to success in building a really enjoyable street car or a successful strip car. There are two basic types of torque converter. The first type is the lock up converter which is used on the cars from the factory. At a given speed or load, the converter will lock up which removes the slip from the equation which improves fuel mileage and minimizes the engine speed required to cruise down the road at the lowest rpm. My opinion is that this is the best type of converter for street and/or street strip cars.
The second type of converter is the non-lock up unit which never fully locks up but does minimize slip as engine speed exceeds the stall speed of the converter. This type of converter weighs less than the lock up and will spool up a bit quicker as a result. The inner workings of these converters can be very complex in order to provide the desired stall speed quickly and efficiently, but then minimize slip after that point in order to maximze power to the rear tires. My OPINION is that this type of converter is best for an all out race car although I admit that I have seen some work quite well on a "driver" without undue loss of fuel mileage. Some cheaper converters may slip something like 20% at wide open throttle and one runs out of rpm before getting to the finish line. This also generates a lot of heat that does the transmission no good.
I said it elsewhere, but a good quality torque converter is not cheap. This is not the place to save money. Spend up front and don't have to do it again.
Injectors, fuel lines, fuel pump, fuel management Injectors have to be sized large enough to provide sufficient fuel to support the horsepower that is the goal of the build. Injectors are rated in pounds of fuel per hour. Often we select injectors that will feed 30 or 40 percent more fuel than we estimate we need for our horsepower goals. This allows not only some top side but also insures the injectors operate with no danger of erratic behavior. Any good vendor should be able to assist you in your needs.
A good 340 size fuel pump should take you into the tens without a problem. If you are spraying alcohol, it will supplement the fuel need with methanol to some extent and this provides more upside.
Any more pump and you will likely find that the fuel lines have become and obstacle to fuel line and the car will need to be replumbed to handle more fuel flow. Some times, people go to a half inch line for the delivery side and used the existing 3/8" as a return line and that will provide more flow to the engine.
Some single pumps in the "340" category may tend to overwhelm the return line at idle and give fuel pressures higher than desired at idle. This may make the engine idle richer than desired. If it is just a small amount that goes away as the throttle is opened slightly. It may necessitate a larger return line in some cases and on some really quick cars, there are pump controllers that can lower the voltage to the pump at lower rpms.
If the problem is small, the blm tables in the chip may adjust for the extra fuel. Speed density type chips often allow for control of the A/F ratios at idle and that may resolve the problem.
Since the '90's certain people have bad mouthed the factory ecms. They are only 8 bits, they are too slow, they are not reliable, etc. It may be that given the age, that may now be a true statement as they will continue to become more problematic altho it is not yet that common a problem. Components like capacitors do age.
Turbotweak and Bailey Engineering joined together and have produced an aftermarket fuel management plug and play system that they call ecu-GN. It uses a MegaSquirt fuel management system that is very sophisticated in operation but can be set up like a factory ecm. When delivered, it comes set up to run your particular combination but you can custom tune to your hearts desire and run it with a modern digital instrument panel. Unlike most standalone systems, this one should run well right out of the box and you can fine tune it for your own desires.
Here is a link to the system https://www.turbotweakstore.com/ecu-GN-Standalone-ECU-for-Turbo-Buicks_p_85.html
If you want to go all out and still have something you can learn to use to maximum extent, add this digital dash https://dd-efi.com/products/12-3-pro-dash-84-87-grand-national
Not cheap but compared to a transmission rebuilt for performance, this is not all that bad. That's my story and I'm sticking to it. You can tailor that however you wish to best suit your significant other! We've come a long way in the past 40 years!
Okay, I quit! I am not getting to 9" rear ends, Turbo350 transmissions, and all the other stuff.