The real FAQs about Forced Induction (addition: 06/16)
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The real FAQs about Forced Induction (addition: 06/16) - 5/1/2007 11:29:54 PM
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SovXietday
Posts: 1868
Joined: 6/29/2006
From: Harleysville, PA
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Okay, so it's time this forum had some good solid answers to the basic forced induction questions, and even the not so basic. Remember, we're trying to design this forum around intelligent discussions and good questions to setups that you want to try. There are many wonderful resources all over this forum and many knowledgable people who would love to answer the questions you have... as long as they're not the generic ones on this following list. Yeah, we get tired of answering the same thing over and over again too. So, to start...
"How much PSI can I run on my engine?"
Common answer = "6 to 8psi." Yes, it's also the wrong answer. The correct answer to this question would be "I have no idea." Why? Keep reading please.
"How many pounds of boost can I run on my stock B16A2 with my T3 Super 60 turbo, tuning on Crome Pro?"
Notice how this question is structured. We need to know AT LEAST 3 things in order to tell you about what you could safely run.
1) What engine you're running, and if it's built (if so, how) or if it's stock.
2) What turbo and as many specs of the turbo that you can give.
3) What you will be tuning with.
Other things that would be great to know would be things like.
4) What size injectors and fuel pump are you running?
5) What MAP sensor are you running?
The truth to the PSI myth is simply this. It doesn't matter. What matters is how much power the engine makes. With good tuning, the following can reasonably be held with these listed engines.
D16Y8/D16Z6 - 225whp - 250whp
D15B/D16Y7 - 200whp
B18A1/B18B1 (LS) - 300whp
B16A2/B18C1/B18C5 - 350whp
B20 - 350whp
K20A2 - 350whp - 400whp
F22C - 400whp (Don't count on the stock S2000 rear holding up to that though)
Built with stock sleeves = up to 500whp.
Built with Sleeves - you better know what you're doing by then.
So, what you need to determine is about how many pounds of boost will get you to your desired goals on the turbo that you have. Smaller turbos will take more boost, larger turbos will take less boost. In the case of the original question, a Super 60 turbo can be maxed out on a stock B16, they're good for about 275-300whp.
Turbo sizing is only one factor to how much boost you can run. You also need enough injector to supply fuel to the engine. Fuel pressure and injector size both will determine what injectors you'll need, but most commonly you will need 550CC injectors for 300whp. There are plenty of injector sizing charts floating around the internet, google them and find out just what size you'll need for your application.
Lastly, along with turbo size and injector, you need to have a MAP sensor that can read the amount of boost you want to run. MAP sensors are measured in units called "bars." 1bar = 14.7psi. The stock Honda MAP sensor = 1.75bar, without going into too much detail the first bar of the MAP sensor is used to read vacuum. The remaining is left for our precious boost. In the case of the Honda MAP sensor, you have a total of about 12psi available until the MAP sensor is maxed and you can no longer tune the car correctly. There are 2, 2.5, 3, 3.5, 4, and 5bar MAP sensors available. Most people use the Motorolla 2.5bar MAP (~22psi) and the GM 3bar (30psi) MAP sensor. These are necessary if you want to boost safely over 12psi. My suggestion would be to only go with what you need, as your partial throttle will suffer the more bars your MAP sensor can read.
"Will this 'ebay link' work well? I like it because it's shiny and they say it's good for blah blah blah."
This is America, we live in a capitalist society and we always have. You get what you pay for, always have, always will. No, it is not good, yes, it will break, yes, it will probably ruin your engine when it does. Stupid question, next!
"What do you mean by "chipping the ECU" and what does it mean to "tune" a car?"
Ok, sit down and learn this. It's very important. First off, if you do not know how a standard internal combustion 4cycle engine works, you need to learn this before any of this will make any sense. Learn it, live it, understand all of it.
As far as chipping an ECU, it basically entails the user installing a programmable 28pin EPROM chip into the ECU. This chip will hold the tuning software and all of the available information for your tune.
Picture from www.phearable.net (ECU and tuning services site.)
Doing this allows you to use a free tuning program like Crome to edit the fuel and timing maps along with many many other features that you can not do on a stock ECU. OBD2 (96-00) people will need a jumper harness to "convert" back to OBD1. OBD0 people can either take the steps to convert to OBD1 (check out rywire.com) or you can use a program similar to Crome called Turbo Edit. Chipping services are also available for OBD0 ECUs.
Why is this important. It is important because not only does a forced induction vehicle require quantive amounts more fuel, but it also requires changes to the ignition timing in order to not detonate and cause engine failure. Explanation following.
These programs work pretty much like a table, each cell is dedicated to it's own MAP reading and RPM value.
This is a screenshot of the software Crome. These values are placed onto the writeable EPROM chip and placed into the ECU, the ECU then reads each cell individually according to the sensor readings. This picture is my high cam ignition timing, so when the MAP reads 10.7psi and the RPMs are at 7500RPMs, the ECU ignites the spark plug 19 degrees prior to TDC.
These systems allow you to have full control over how much fuel the engine has through the entire map and also timing as well. With correctly sized injectors you will be able to inject enough fuel to be stoich at idle, and rich at boost. This is part ONE of tuning, part TWO is much more important.
TIMING. Timing is what makes and breaks an engine. If it's not dead on, the engine will detonate, and destroy a piston or throw a rod. Nope, not a good thing. You may have heard of the of the acronym called "TDC" or "Top Dead Center." This refers to the piston being at the very top of it's stroke. This would read as 0 degrees on the crank pulley. So I'm sure you're asking yourself "well why wouldn't you want to make the spark happen at TDC?" Simple, ignition and fuel burn is not instantaneous, the flame front will follow the piston down the cylinder and you will lose an immense amount of power.
You need to ignite the fuel in the cylinder BEFORE the piston reaches TDC, that way when the fuel reaches full combustion the piston has reached just beyond TDC and recieves a very efficient and powerful push back down the cylinder. The numbers in the cells in the picture above is the degree on the crank pulley from where TDC exists and the TDC mark actually is. The crank rotates 360 degrees, 19 degrees before 360/0 the spark ignites the fuel.
A GREAT visual reference of what I mean is found at this link here.
http://www.autoblog.com/2007/04/27/video-so-thats-what-it-looks-like-slo-mo-combustion-closeu/
You can watch as the spark plug ignites the fuel as the piston is still coming up, and then after the piston reaches TDC full combustion occurs and the flame front strikes the top of the piston. Unfortunately there is no downstroke but I would assume you can figure it out from there... the piston goes down!
Now, if the fuel is ignited too far in advance, full combustion will occur before the piston reaches TDC and effectively slam into the piston that is going the other direction. This is one of many forms of detonation, but it can only be avoided using a chipped ECU and with a good tune. This is extremely important for turbocharged vehicles, as the very dense charge in the cylinder creates a very fast and very powerful explosion and if the timing is too far advanced (if you were to use a VAFC or an FMU) you will quickly destroy the engine, not to mention not make power!
If none of this made sense, then please just take this away. Get a chipped ECU, and get the car tuned with at least Crome... if you can afford Hondata or Neptune they will be a better choice.
"I'm running on the basemap, is it ok to boost?" (added 06/16/07)
No, it is not ok! Basemaps are something designed to allow you to drive your car from your house to the dyno. Most basemaps are extremely rich and will be just fine with low load driving to your local tuner, but a basemap is just a starting point for tuners. My suggestion would be to stay in vacuum during any driving that you need to do with your car before it is at least street tuned.
"I'm getting tuned tomorrow, what should I do?" (added 06/16/07)
Here's a very simple checklist to do before you ever get on the dyno to have your car tuned. This also applies to street tunes.
-Make sure you have no leaks and no Check Engline Lights. If you do, fix them. If you do not, you will be wasting money as the tuner will not be able to effectively tune your vehicle.
-Check your fluids! Make sure they are full. Dyno tuning will put your car through extreme parameters and it must be up to the task. Low oil or low coolant is a big problem.
-Bring a few extra sets of spark plugs. When you buy colder spark plugs for your car, buy a couple sets. 3-4 is a good number, most of them are cheap so it shouldn't set you back too far. That way, you have a fresh set of plugs if the tuner fowls them out (can happen easily) and you will use them later if you don't use them that day anyway.
-Do not roll in on slicks. Bring good street tires, slicks have a tendency to explode on the dyno and it will without a doubt tear your body to pieces.
-Have a game plan. How many PSI do you want to run on your engine, do you have a way of acheiving said PSI (boost controller?). Get all of your gear together before you go or you'll be going back.
-Bring a buddy. You never know what will happen, you don't want to get stranded at some dude's shop. Also, friends are good for moral support and to hold the camera while you smile in front of your newly tuned monster. 
For people who are learning to tune themselves, do all of the above and add the following.
-Bring your laptop, wideband, all necessary cables, emmulators, and burners.
-Bring tools! Spark plug pullers, 10mm wrench to pull your ECU out, phillips screwdriver to get the screws off the faceplate.
-Make sure your software is working, make sure all of your emmulators and burners connect correctly before you get there.
-Make sure you have a game plan before you get there. Remember, set timing very conservative, get your fuel curve first. Establish peak VE, reflect the timing graph (hump in fuel, dip in timing) Start slowly increasing timing, adjust fuel as needed, stop and pull a degree of timing once the car stops making power, dyno one last time and those are your final numbers. Remember on a Honda to increase fuel trim in cylinder #3 by 2-3%.
"Octane booster? Race gas? What gas?"
Gasoline has different mixes and octane ratings. The most common ones are 87, 89. 91, and 93. Some people have higher octane available at local pumps, lucky them.
Basically the octane rating is simply the amount of compression that the fuel needs to undergo before it can ignite. So, 87 will ignite sooner and burn quicker than 93 will, and 93 will ignite faster and burn faster than 100. Run the octane that you are tuned with. Running a lower octane may cause you to detonate because the charge will burn too early! Running a higher octane will probably make the engine run hotter and lose power as you will effectively be retarding the timing further and chasing the piston again. When you run race gas, you must tune for it. Race gas allows you to run a further advanced timing (slower burn) which in turn makes more power. It also allows you to run high boost applications which will keep the charges from exploding too early and once again detonating in the engine. The general rule of thumb is 20psi+ go with 100 octane or more. For any turbocharged application, I'd suggest running the highest octane that you can find at your local pumps.
"Is the B18C5 compression too high for boost?"
Compression is commonly around 40:1 with just low boost, much higher under high boost applications. Higher compression only makes the tune harder, but with a good tune the engine will be just as reliable as a low compression engine. 11:5:1 compression is peanuts when it comes to Forced Induction.
Probably will add more to this when I get the chance.
< Message edited by SovXietday -- 6/16/2007 7:42:30 PM >
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Champ White 1996 Civic Hatchback - 57trim SOHC
Black 1998 Z28 Camaro - LS1 M6
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RE: The real FAQs about Forced Induction - 5/1/2007 11:31:54 PM
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drbyers
Posts: 4301
Joined: 10/14/2005
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holy shizNat.
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RE: The real FAQs about Forced Induction - 5/1/2007 11:34:31 PM
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phan10m
Posts: 928
Joined: 10/12/2006
From: Chi.
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uhhh.. too tired to read all that..
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RE: The real FAQs about Forced Induction - 5/1/2007 11:35:02 PM
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johnny
Posts: 1906
Joined: 10/30/2006
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STICKY
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RE: The real FAQs about Forced Induction - 5/1/2007 11:40:03 PM
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SovXietday
Posts: 1868
Joined: 6/29/2006
From: Harleysville, PA
Status: offline
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My fingers burn, lol.
If anyone has a FAQ they would like me to add post up, my brain is about fried right now and I can't remember any more lol.
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Champ White 1996 Civic Hatchback - 57trim SOHC
Black 1998 Z28 Camaro - LS1 M6
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RE: The real FAQs about Forced Induction - 5/2/2007 3:17:00 AM
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gsumano
Posts: 1164
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Turbo d16y8
gt28r @ 7psi
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RE: The real FAQs about Forced Induction - 5/2/2007 5:41:31 AM
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aryiman98civic
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sticky
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