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8,575 Posts
Discussion Starter · #1 ·
Hello all,
This will be the new thread for all FAQ and DIY information for the Forced Induction Forum. I will be adding all threads from the past that have been useful to all of us. In an attempt to keep the information neatly organized, only moderators will be allowed to edit the FAQ.
Thank you in advance for your cooperation and support. http://****************.com/smile/emthup.gif
If you do not see the information you are looking for, don't forget to search both recent and archived threads. Many topics have been discussed in the past and there is a good chance you will be able to find some information on the subject you researching. If your search does not yield the information you are seeking, please don't hesitate to post.
In the future if you see something I missed or something that belongs in the FAQ please send an instant message to one of the Forced Induction moderators and ask them to add it.

Modified by herbehop at 1:16 PM 5-4-2007

8,575 Posts
Discussion Starter · #3 ·
Re: Forced Induction FAQ *NEW* (herbehop)

FI : Forced Induction
FMIC : Front-Mount InterCooler
IC : InterCooler
FPR : Fuel Pressure Regulator
FMU : Fuel Management Unit
BOV : Blow Off Valve
DV : Diverter Valve
MAF : Mass Air Flow sensor
MAP : Manifold Absolute Pressure sensor (Also a word to describe a table of values, such as an ignition map)
CR : Compression Ratio
DP : Down Pipe
WG : Waste Gate
A/A : Air to Air Intercooler
A/W : Air to Water Intercooler
WHP : Wheel Horsepower as read by a dyno
BHP : Brake Horsepower (basically the same as crank HP)
WTQ : Wheel Torque
AFR : Air Fuel Ratio
WB or WBO2 : Wideband Oxygen Sensor
SMIC : Side Mount Intercooler
W/I : Water Injection
EMS: Engine Management System (usually aftermarket programmable)
VR: Variable Reluctance (crank sensor) or short for VR6
posted by:
and Angular

Modified by herbehop at 7:01 PM 1-4-2007

8,575 Posts
Discussion Starter · #6 ·
Re: (herbehop)

How do I pressure test my intake system for boost leaks?
Posted by: Angular
A: Construct a "air compressor to turbo inlet adapter" using a PVC coupler, PVC end caps, and other misc hardware from a place like Home Depot. This will fit onto your turbo compressor inlet and allow you to pressurize the intake. Drill a hole in the PVC end cap and thread in a 1/4 male quick-connect fitting that your air hose will attach to. If it doesn't fit tightly (air tight!), use some 5 minute epoxy on the threads. Purchase an adjustable air pressure regulator from Sears for $35 if your air compressor doesn't already have one. Attach the adapter to your turbo inlet. Dial the air pressure down to ZERO and connect it to your adapter. Remove the oil filler cap as air will usually sneak past the TB and ultimately need to escape from the crankcase. Slow increase the air pressure to 10 PSI and listen for leaks (you will hear them if they are there). If you hear a leak feel around with your hand to verify where the air is coming from.
Note: This technique is basically the same as AWE Tuning's FAQ on how to pressure test the Audi 2.7T intake system, except for single turbo applications you connect the air source directly to the turbo compressor inlet.

8,575 Posts
Discussion Starter · #7 ·
Re: Forced Induction FAQ *NEW* (herbehop)

Injector Sizing - Posted by Jeffrey Atwood

Injector sizing:
These are for the Mk3 cars, BOTH VR6 and 2L
but the general philosophy can be applied to ANY car.
This is for NON FMU application. This is NO guarantee that you WILL
make these hp numbers just that you can support it.
Note: HP calcs assume .55 BSFC and 85% duty for REFERENCE only, and the boost
is 'close' to where you'll need to be.
Stock inj. size: 19#/hr
6cyl: 176whp 4cyl: 117whp
~8psi of boost: 30#/hr
6cyl: 278whp 4cyl: 185whp
~12psi of boost: 36#/hr
6cyl: 333whp 4cyl: 222whp
~16psi of boost: 42#/hr
6cyl: 389whp 4cyl: 260whp
~20psi of boost: 48#/hr
6cyl: 445whp 4cyl: 296whp
~24psi of boost: 52#/hr
6cyl: 482whp 4cyl: 321whp (I have been here, 333whp B16A)
~33psi of boost: 62#/hr
6cyl: 575whp 4cyl: 383whp

Modified by herbehop at 11:43 PM 1-3-2007

8,575 Posts
Discussion Starter · #11 ·
Re: Forced Induction FAQ *NEW* (herbehop)

Wastegate Springs
Posted by: I am Jack's VR6
TiAL wastegate spring list:
Wastegate - 35mm
BAR // PSI // Color // OD
0.30bar // 4.35psi // Sm. Yellow // 1.875in
0.45bar // 6.53psi // Sm. Red
0.65bar // 9.43psi // Sm. Green
0.8bar // 11.60psi // Sm. Blue

Wastegate - 35mmHP
BAR // PSI // Color // OD
0.95bar // 13.78psi // BigYellow // 1.875in
1.10bar // 15.95psi // BigRed
1.35bar // 19.58psi // BigGreen
1.5bar // 21.75psi // BigBlue

Wastegate - 38/40mm
BAR // PSI // Color // OD
0.25bar // 3.63psi // Sm. Yellow // 1.875in
0.4bar // 5.80psi // Sm. Red
0.5bar // 7.25psi // Sm. Green
0.6bar // 8.70psi // Sm. Blue
0.7bar // 10.15psi // Big Yellow 2.36in
0.8bar // 11.60psi // Big Red
0.9bar // 13.05psi // Big Green
1.0bar // 14.50psi // Big Blue
1.1bar // 15.95psi // **
1.2bar // 17.40psi // **
1.3bar // 18.95psi // **
1.4bar // 20.30psi // **
1.5bar // 21.75psi // **
1.6bar // 23.20psi // **
Wastegate - 44/46mm
BAR // PSI // Color // OD
0.2bar // 2.90psi // Sm. Yellow // 1.875in
0.3bar // 4.35psi // Sm. Red
0.4bar // 5.80psi // Sm. Green
0.5bar // 7.25psi // Sm. Blue
0.6bar // 8.70psi // Big Yellow // 2.36in
0.7bar // 10.15psi // Big Red
0.8bar // 11.60psi // Big Green
0.9bar // 13.05psi // Big Blue
1.0bar // 14.50psi // **
1.1bar // 15.95psi // **
1.2bar // 17.40psi // **
1.3bar // 18.95psi // **
1.4bar // 20.30psi // **
*All Standard WG35mm Springs can also be used for WG35mmHP
**You can combine Big&Small Springs to get the PSI that you need for HP

8,575 Posts
Discussion Starter · #12 ·
Re: Forced Induction FAQ *NEW* (herbehop)

How to find turbo trim
posted by: killa

How to find the turbo trim:
The Trim is just the relation of the inducer to the exducer squared.
(I/E)^2 x 100
Take for example the T3 60 trim, its inducer measures 1.830" and its excuder 2.367" just like every other T3 exducer.
Divide the inducer (1.830) by the exducer (2.367) and you get .7731305. Square that number and you'll end up with a .5977, easily rounded off to .60. Multiply that .60 by 100 and you get a T3 60 trim.
Let's now do it for a T4 application:
T04E 60 trim:
Inducer: 2.290"
Exducer: 2.950"
Now, do the same formula (I/E)^2 *100
2.290/2.950 = .7762711 = .6025 or .60, multiply by 100 and you get a T04E 60 trim
Same trims, but totally different wheels.
T-series, however, work a little different. the number after the T stands for the size of the inducer in millimiters, so a T-61 would have a 61mm inducer.
Hope this helps

8,575 Posts
Discussion Starter · #13 ·
Re: Forced Induction FAQ *NEW* (herbehop)

Are my Rings/Ring lands/Pistons blown? How do I tell?"
Posted by: lugnuts
- Rings dont blow, its your pistons. "ring lands" are the grooves in the pistons that hold the rings in.
- If you just put a turbo/sc/or nitrous on your engine and now its running on less all of its cylinders, and/or there is a massive amount of oil and smoke coming from your crankcase/valvecover breathers, the chances are the problem is broken piston ring lands caused by detonation. How you check the condition of your engine is to do a:
1) compression test and/or 2) leak-down test.
Testing the condition of your engine" or, "Denial aint just a river in Egypt"
1: Compression Test.
Very easy to do. Cost of compression gauge is ~$35 at Sears or any other auto parts store. Time to do test is 10 minutes - 1 hour. *Much* less time than trying to find correct information on the Internet.
Basically you remove all of your spark plugs and install the gauge, open the throttle, and crank the motor 5-10 times. Measure and record the readings form every cylinder. Compare them to specs for your motor (Bently manual) or if you want general common sense answers then 140-220 (depending on the compression ratio of the engine) is good , less than 100-120 is telling you there is a problem. And if you have some cylinders at say 150 psi and one or more at less than 100 then you have found your problem right there.

2: Leak-down Test.
Consult your local technician. Leak down testing is good when you want to find your specific problem before tearing the engine down. But if your engine has 100 psi or less on one cylinder then you may find this step to be a waste of $$$.

8,575 Posts
Discussion Starter · #14 ·
Re: Forced Induction FAQ *NEW* (herbehop)

How to read a compressor map
Posted by: O2VW1.8T
taken from honda-tech

using a map of a T04E 60 trim I will explain all the numbers on the map

1-left side, PRESSURE RATIO
(14.7 + amount of boost) / 14.7 = PR
so to figure out the PR for 8 PSI
(14.7 + 8) / 14.7 = 1.54 PR

2-bottom side, AIRFLOW RATE UNDER BOOST (LB/MIN on this map)
Most methods of calculation your engine's airflow rate will give you the answer in cubic feet per minute (CFM). However most compressor maps measure airflow rate in pounds per minute (LB/MIN). As some of you may know the weight of air varies with the temperature. To convert CFM to LB/MIN use the following numbers.
@ 48 degrees F : (CFM * 0.078125) = LB/MIN
@112 degrees F : (CFM * 0.070318) = LB/MIN
@175 degrees F : (CFM * 0.06251) = LB/MIN
Say for example our airflow rate is 500 CFM , and the temperature is 112 degrees F.
(500 * 0.070318) = 35.16 LB/MIN
*For those of you that know anything about ideal gas law, if you know a better way of explaining how to convert CFM to LB/MIN, your input would be appreciated. But please explain it in "laymans" terms, so that everyone can get a grasp on it.

3-dotted line on far left side of "ovals", SURGE LIMIT
It is important to try and keep yourself on the right side of this dotted line whenever possible. If you fall to the left of this dotted line you will experience compressor surge. This type of compressor surge will occur when there is too much boost, but not enough airflow through the system, usually this is between idle and the point at which full boost is reached. The chirping sound that can be heard is a result of the oscillating air. This sound is often described as a "Snakelike" sound or a che-che-che sound.
*staying in the "surge limit" area for too long could possibly damage your turbo.

4-numbers on far right, 46,020, 69,640, 83,972 etc, COMPRESSOR RPM
This is RPM at which the compressor fans will be turning. an average RPM is between 90,000 and 130,000. The line that branches out from each of these numbers that goes towards the surge limit line shows you the RPM range of the compressor fan across the entire compressor map.

This is related to the temp of air and how much it is being heated up as it is being compressed by the compressor. A low number (60%) means that the compressor is heating the air more a high number (78%) means the air is not heated as much when it is compressed.

I you look closely you will see that the compressor efficiency numbers usually sit right on top of one of these Oval lines. These Ovals show you the boundaries of the compressor efficiency at the different percentiles. Think of it as a topography map that shows you different elevations or changes in elevations. The innermost Oval on the sample T04 E 60" is not labeleb but it is probably 79% or 80%, so any where inside that Oval and you would be operating in the 80% range of that compressor.

how to choose the right IC piping
Airflow velocity for different intercooler piping diameters (2.0 2.25 2.5 2.75 3.0 inches)
Hi guys,
In the last few weeks I've seen several posts on whether it is ok to use 2.5" or higher piping, or if somebody could use their ITR AEM CAI as a charge pipe. I tried to help all of them best I could, but jus a short while ago I helped another H-T member out with a similar question. I searched online and used a flow calculator to help me figure out the airflow velocity for a given area and cfm. The site I used is THIS ONE. As you guys can see it has the area in length times width instead of PiRsquare which is the area of a circle. I took the area of each pipie diameter and usd the equivalent area of a square and used those as my length and width. I made it simple and just took the area of the circle and divided by 2. The resulting number was usd as my length and 2 was used as my width.
Your actual results may vary (ie when you add an IC) so just use my numbers as sort of a bench mark to compare different piping sizes. One thing you guys will notice is that none of the velocites goes above 304 MPH or 0.4 mach. According to Corky Bell, Maximum Boost pg 61, 304 MPH or 0.4 mach is the point at which airflow meets increased resistance (drag) and flow losses are experienced.
Anyways here are the numbers I came up with. The velocities are in miles per hour and mach, and the flow rates are in cfm. Measurements for the piping are in inches.
0.4 mach = 304 MPH
2" piping
1.57 x 2 = 3.14 sq in
300 cfm = 156 mph = 0.20 mach
400 cfm = 208 mph = 0.27 mach
500 cfm = 261 mph = 0.34 mach
585 cfm max = 304 mph = 0.40 mach

2.25" piping
3.9740625 sq in = 1.98703125 x 2
300 cfm = 123 mph = 0.16 mach
400 cfm = 164 mph = 0.21 mach
500 cfm = 205 mph = 0.26 mach
600 cfm = 247 mph = 0.32 mach
700 cfm = 288 mph = 0.37 mach
740 cfm max = 304 mph = 0.40 mach

2.5" piping
4.90625 sq in = 2.453125 x 2
300 cfm = 100 mph = 0.13 mach
400 cfm = 133 mph = 0.17 mach
500 cfm = 166 mph = 0.21 mach
600 cfm = 200 mph = 0.26 mach
700 cfm = 233 mph = 0.30 mach
800 cfm = 266 mph = 0.34 mach
900 cfm = 300 mph = 0.39 mach
913 cfm max = 304 mph = 0.40 mach

2.75" piping
5.9365625 sq in = 2.96828125 x 2
300 cfm = 82 mph = 0.10 mach
400 cfm = 110 mph = 0.14 mach
500 cfm = 137 mph = 0.17 mach
600 cfm = 165 mph = 0.21 mach
700 cfm = 192 mph = 0.25 mach
800 cfm = 220 mph = 0.28 mach
900 cfm = 248 mph = 0.32 mach
1000 cfm = 275 mph = 0.36 mach
1100 cfm max = 303 mph = 0.40 mach

3.0" piping
7.065 sq in = 3.5325 x 2
300 cfm = 69 mph = 0.09 mach
400 cfm = 92 mph = 0.12 mach
500 cfm = 115 mph = 0.15 mach
600 cfm = 138 mph = 0.18 mach
700 cfm = 162 mph = 0.21 mach
800 cfm = 185 mph = 0.24 mach
900 cfm = 208 mph = 0.27 mach
1000 cfm = 231 mph = 0.30 mach
1100 cfm = 254 cfm = 0.33 mach
1200 cfm = 277 mph = 0.36 mach
1300 cfm max= 301 mph = 0.39 mach

8,575 Posts
Discussion Starter · #16 ·
Re: Forced Induction FAQ *NEW* (LSinLV)

C2 Supercharger Belt setup
Picture is courtesy of C2 Mototsports
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