I have notice that a few people are interested in force induction but afraid due to the horror stories. If anyone here could jump in and assist me with a list so we can help those that are new to forced induction I would really appreciate it. I myself have only about 2 years of experience so I am still a newbie! But hopefully I can help a little... I don't have a lot of time tonight to answer all, I will try to update with more answers tomorrow.


Turbo's do not have low end power...
Depends on the size of the Turbo! The size of a turbo that would be design for the XB engine would have to be pretty small in order to make it bolt on friendly, which in turn will spool a lot faster than a 60-1 with a Stage 5 wheel for a Honda.
Superchargers do not put wear on the engine like a turbo
The principle is the same for both, which is forced induction in order to produce more horse power which cause internals to move faster. The wear and tear should be the same as long as you have proper fuel management and continuing to properly maintenance the vehicle.

What is Tuning?
Whats the purpose of a BOV?(Blow-off Valvle)
What is a Turbo Timer?
What is EGT (Exhaust Gas Temp)?
Do I need to use 93 Octane?
Do I need an Intercooler?
What is Pinging?
What is the difference between Tubular and Log Style manifolds?
How many pounds of boost can my block handle?
Why should I upgrade my internals?

 

No matter how small the turbo, its never going to have the instant on boost of a roots supercharger.

But, people should also know that other styles of superchargers (centrifugal, such as vortech) are much like turbos, in that the boost goes up as rpms go up.

 

What is Tuning?
Sort of a broad term. Um...if you buy a already put together turbo kit it may work fine right out of the box, but if you build a turbo or want to add more boost to you turbo kit or whatever, you'll need to tune it. This may mean anything from adjusting the fuel to air ratio to changing your spark plugs to "cooler" plugs. I hope thats what you mean when you ask'd this question...I was a little unclear.

Whats the purpose of a BOV?(Blow-off Valvle)
BOV is used to relieve compressor surge without reducing compressor speed. It does this by venting out excess presure when it is not under load {when you shift}. This will prevent pressure from backing up into the compressor housing, causing the turbo impeller blade to rapidly stop or even worse, to spin backwards. Basically its like a fuse (but with psi instead of electricity). It is used to protect your turbo, and it sounds cool too.

What is a Turbo Timer?
A turbo timer is used to keep the life of your turbo nice and long. After you shut off your car a turbo timer will keep your car running to let the oil around your turbo cool down then it'll turn off your car. The intense heat absorbed by the turbo may turn the oil solid. THis is bad so most factory turbo cars ask the owner to keep the car idling for a while after you're done driving. If you don't want to sit there and wait get a turbo timer.

What is EGT (Exhaust Gas Temp)?
Turbos use exhaust gases to create boost or psi thus creating power. These gases are hot. The hotter the air the more pressure it will create. If the exhaust gas temp is too high and creates too much pressure it can damage the turbo. Its something to keep an eye on (with a gauge) to see how your engine is preforming and to make sure your turbo isn't getting too hot.

Do I need to use 93 Octane?
It depends. The octane of gas you need to use isn't due to fact that you have a turbo, in actuallity it is the compression ratio. Boosting your car makes the compression ration higher. If its too high you'll need higher octane gas. Even guys that go all motor with super high compression need higher octane gas.

Do I need an Intercooler?
In a word no. In most (if not all) its totally optional. The intercooler will cool down the air going into the turbo thus making your turbo able to handle more boost.

I'm not the an expert so feel free to correct me. I got tired and stopped short of the end of the questions...LoL...sorry maybe i'll do more later.[/quote]

 

reguarding your do i need an intercooler answer

the air/boost is produce from the TC so none of the air that the intercooler is keeping nice and chilly goes into the TC it all goes into the engine thus keeping your engine from rising to extreme temps which causes over heating. it is up to you if you want an intercooler or not it is helpful. but with the air being colder it becomes denser. its like putting a ballon filled with air into the freezer within time the ballon gets smaller because the air becomes dense so in other words it loses air which causes the full 7psi of boost to really be 6 or 6.5 depending on the intercooler which results in a gain or hp but a lose in boost good thing tho you can always rasie the boost

 

That "dense" air is what you want getting into the combustion chamber. The more available oxygen in the chamber.......the more fuel can combust with it............ie, more power. The point of a turbo charger is to force more OXYGEN into the chamber.......not just "air". An intercooler helps maintain air density, and thus higher OXYGEN concentration in the combustion chamber. Also, you want to keep the heat of the air entering the combustion chamber down as much as possible. When running high boost, there is a danger of the air/fuel mixture in your combustion chambers actually igniting before its supposed to (ie, when the spark plug fires). This can be DEATH for your engine. Keeping the temperature of the air down helps prevent this.

That's my understanding on the topic anyway.

KiL

 

Im kinda busy @ work so i will be answering questions one or two @ a time. I'll start with the easy ones!.. A couple were already answered.. let me add to those.

Superchargers do not put wear on the engine like a turbo ..
Everything is going to put wear on your engine. IMO turbo's would have less
wear then typical superchargers. Typical S/C are on all the time..Turbochargers
build boost @ a certain RPM... so if you drive around while not boosting on a turbo that equals less wear right? right!

What is a Turbo Timer?
.. This is was answer fairly well by burn0ut... but IMO it's a complete waste of money!
You can achieve the same affect by babying your care before you get home and not boosting. Spend the $100 on something else.

What is EGT?
Exhaust Gas Temp... This is what I learned from a DSM buddy of mine.

What everyone says is high EGTs = high combustion temps = lean mixture. So most would add fuel. Low EGTs = low combustion temps = Rich mixture. Lean it out a bit right? kinda.. but not really... kinda hard to explain..and to be honest with you I can't put it in my own words. Im going to post his post..

....Myth number one: The internal engine parts will melt at over 900 degrees C or 1650 F. Here is some big news. Combustion temps are over 2000 degrees and can reach 3 to 4 thousand. So why dont the parts melt? Just a few quick reasons. One is heat sink capacity. Two is heat transfer from the piston to the cylinder wall through the rings. Three is heat transfer to the oil that is splashed up or squirted on the piston and other parts. Four is heat transfer into the cooling system through the head or block. In fact, so much heat is taken out through these methods that by the time the combustion gasses get to the manifold and EGT probe, temp is down to 900 c or 1650 f ;o) Some heat is also lost in the conversion of heat energy to mechanical energy in the form of gas expansion. So that myth goes down the terlet.

Myth number two. If EGT is high the mixture is too lean. Well what happens when the mixture is (way) too rich? It is still burning as the exhaust valve opens. Fire in the manifold WILL heat up the probe. Not rocket science. I have seen a dozen people add fuel and add fuel and EGT temps dont go down. Lean out to where they are supposed to be though and its all normal again. I know it goes against the "Internet Laws of EGT Guages," but its the truth. Also, what happens when the mixture is WAY too lean? Temps go down. Why? Less fuel to support combustion. It is entirely possible to be so lean that combustion temps drop so low that there isnt enough heat energy to increase pressure enough to cause knock. I have seen this happen on my car after a baro wire mod gone wrong.

Myth number three. If EGT is too low, the mixture is too rich. Not necessarily, though this is way more possible than vice versa. It depends entirely on the setup. The more knock prone you are the more fuel you need. That slight difference in EGT temp will show itself if and only if you are getting maximum timing advance for your setup.

So what does the EGT tell you? I've said it a thousand times before, as have hundreds of other DSMers, but ponder this. You are knocking. For ANY reason, not just lean mixture. The knock sensor picks this up and reports to the ECU. Now this may be hard for some of you to believe apparently, but when the ECU senses knock, it pulls timing. The amount of timing it pulls will vary based on the "normal" knock sensor noise threshold, how strong the signal is, and how long it has been going on, among other factors. The ECU comes up with a kncok retard value, and that amount of timing is pulled back from where the full timing would be based on the timing map you are currently on. Here is what I mean by this. The timing map you are currently on is based on airflow mostly, but also coolant temp and intake temp and other factors. This map or table includes timing values for each rpm point. So lets say for where your car curently is, you are on a map that says at this rpm maximum advance would be 17 degrees. But knock retard is 3 degrees. What will your timing be? Get out the calculators. 14 degrees is what you will get.

Now what does retarded timing have to do with this... If the timing is retarded enough, as in LESS ADVANCE, the ignition event occurs LATER in the combustion cycle, in degrees of crank rotation. If the mixture is ignited late enough, it is still burning as the exhaust valve opens. Refer to "Myth number two." Fire in the hole will heat up the probe. THIS IS WHY high EGT temps mean that you are getting knock and reduced timing advance. Read it a few times. Let it soak in.

Furthermore, the amount of change in EGT temps per change in air fuel ratio is MINOR, while conversely, the change in exhaust gas temps is SUBSTANTIAL when the timing is retarded and there is fire on the probe. Why? The increased heat caused by a leaner mixture is mostly absorbed by the motor or converted to additional mechanical engery. The latter is the cause for the increase in power when you can lean out without knocking (<- key phrase, pay attention). By the time the combustion gasses get to the probe, the difference is now slight. In contrast, the difference in temps between normal exhaust gasses and fire is very significant and it show up easily on the guage. Now it is important to remember that the higher combustion temperatures caused by a lean mixture not only increase mechanical output, but increase a motor's (or cylinder's) tendency to knock. And again, this knock brings on timing retard, which brings on fire in the hole, which brings on a high EGT temp reported on the guage. THIS IS WHY poeple confuse high EGT temps caused by mixture with high EGT temps caused by knock. Because both usually happen at the same time when fuel tuning. You can also have one without the other, as is the case with mechanical knock or phantom knock.

So now that we got that straight...

Other reasons why EGT is not a good way to tune, without a logger. The ideal temperature will vary with EVERY car and EVERY setup and EVERY set of conditions. I do upwards of 300 drag passes a year and have clearly observed and datalogged this. With that established, the only way to find the ideal EGT temp for your setup/car/conditions/gear is to datalog to see what your timing is. At the point you develop knock you can get an idea of where you want EGT. The problem is, as I stated above, when you have full timing the difference in temperature effected by changes in air fuel ratio is very small. This is complicated even more by my next point:

EGT guages are not very accurate, nor are they precise. Yet another reason to need a datalogger to verify and validate what you are seeing on the EGT guage... The probes are slow to respond, and I will explain why. The rate at which an object changes temperature varies directly as the the difference between the temperature of the object and the temperature of its surroundings. In this case the object is the probe, and the surroundings are the exhaust gasses. What this tells us is that the greater the difference in the temp of the probe and the temp of the gasses the greater the RATE OF CHANGE of temperature. So as the temp of the probe rises (or falls) to match the temp of the exhaust gasses, the difference between the two temps is decreasing. This slows the rate of change. And the cycle continues... So as you can see this is not a linear function, its a curve. This is why poeple often say that the guage reacts slow, or to estimate how fast the needle is moving to estimate where it would really be if it was faster, etc. This is a fundamental problem for both accuracy (especially) and precision (not so much). Another problem is that in general they tend to fail on the low side, meaning they will read colder than what the case really is. So you'll lean out more and more. What happens then is you seem knock "easier" and the tuning window (based on EGT temps) becomes very small and touchy. I have been there, and done that. This is not the way I would choose to tune my car But if so many people insist this is the way to go, what can I say.....


Sorry for the long post, but I'm sure everyone will learn a lot from that. I'll answer some more later.

 

wrong, no supercharger boosts all the time, when you are just cruising around, there is no boost at all.

Please drive around in a boost gauge equipped supercharged car sometime if you don't believe me.

 

i should have said most of the time. regardless.. if you have a turbo you can drive it in low RPM even @ full throttle until it starts spooling, without boost. You can't got WOT with a typical s/c @ 1500 rpms and have 0 boost. That's what i meant.

 

the blitz supercharger has a electronic clutch on it....i would guess you could shut it off all together if u didnt want to boost....i know the jackson racing supercharger i had had a valve in it that opened below 3,000 and put my manifold back into vaccum....or if i was cruising on the freeway at a fairly constant rpm is would go into vaccum....if u punch it, it would close the valve and go to boost instantly....wouldnt be hard to setup on the scion....but also for turbo...u could just setup a boost controller and run it at a super low amount of boost....or a dual boost controller on turbo would do it....but you would still be boosting a little bit....supercharger u could kill the boost completely

just read that the blitz does have a electronic clutch and u can shut it off all together.....thats beats the hell out of any turbo setup....i can choose when to boost and at what rpm to kick in at if i want...has low med high settings