Turbochargers
This article is part one of a series about turbochargers. In this article, we’ll introduce the equations you need to calculate how much air a turbocharger is flowing. We’ll also see how to calculate the pressure ratio, outlet air temperature, and density ratio. Once we’ve gotten the raw numbers, you’ll learn how to plot them on a compressor flow map and how to read the results.
Don’t worry about getting drowned in math, we’ll take you through it step by step. At the end of the article, we’ll provide an easy to use calculator you can download and use to make all of these calculations yourself without having to step through all of the equations.
What is all of this information good for, anyway? Lots of things actually; in this issue we’ll use it to see how turbo/engine performance is affected by altitude. In future issues, we’ll show you how it relates to surging, choke flow (the maximum amount of air your turbo can move), selecting an upgrade turbo, and the basics of compound turbocharging.
Let’s start out by looking at the numbers for a...
My Truck Won't Start!
It’s a cold winter day, and your Power Stroke won’t start. What do you do?
1. As we’ve stated before, the number one failure that will keep you from starting your truck is the glow plug relay (GPR). The first thing you should do is get your spare glow plug relay out and replace the one in the truck. You do have a spare glow plug relay, right? Chances are, this will get you back on the road.
The easiest thing to do is to just replace the GPR and see if it fixes the problem. However, if you want to test the operation of your current glow plug relay, here’s how:
The glow plug relay is located to the left (passenger side) and slightly behind the fuel filter, on the passenger side valve cover. It’s a lot easier to get to if you remove the engine appearance cover. 1999.5 and up truck have two relays in this location, on for the glow plugs and one for the intake air heater. The Ford workshop manuals indicate that the glow plug relay...
Cold Weather Operation
Diesel engines behave very differently than gas engines during the winter, especially starting and right after start up. This month’s tech article will explain what you need to know for operating your Power Stroke during the winter. First we’ll talk about how all of the cold weather systems on the engine work, and what you should expect from your truck during cold weather. After that, we’ll explain what you can do to keep your Power Stroke running in top condition as the winter moves in.
Starting Your Truck
Diesel engines work on the concept of compression ignition; as the air in the cylinder is compressed, it is heated to the ignition point of the fuel. If the air being brought into the engine is too cold, it may not get heated enough to ignite the fuel, or to fully burn it. This is why diesels are traditionally difficult to start in the winter time.
The glow plug system is the primary way of assisting the engine startup. When the engine oil is less than 131° F, the powertrain control module (PCM) will energize...
Stoichiometric A/F Ratio Meter
The A/F Ratio Meter is a voltmeter with a range of 0 to 1 Volt. The meter displays the output voltage of the vehicles oxygen sensor through 20 LED’s. The first LED will come on at a voltage of .050V, the second at .100V, the third at .150V, etc.
LEAN RANGE: Four red LED’s (.050 to .249V)
STOICHIOMETRIC RANGE: Ten yellow LED’s (.250 to .749V)
RICH RANGE: Six green LED’s (.750 to 1.000V)
The stoichiometric (STOICH) air/fuel ratio is the chemically correct ratio, theoretically all of the oxygen and all of the fuel are consumed. The mixture is neither rich nor lean. However, due to the fact that combustion is never perfect in the real world, there will always be a small amount of oxygen left in the exhaust. This small amount that is left is what the oxygen sensor measures.
The smaller the amount of oxygen that is left in the exhaust, the richer the A/F ratio is, and the higher the oxygen sensor voltage is. The on-board computer or Powertrain Control Module...
Testing Distributors
Testing…1, 2, 3…
Many of you have had difficulty in testing distributors with the MSD persuader found in all of our stores.
I’ll attempt to shed some light on this one more time. In addition there are some things to consider when selling the latest HOL stand alone distributors, or for that matter, any two wire stand alone distributor. First off is the counter display.
As you can see it is a simple matter of duplicating the installation in the vehicle. Coil connections, (don’t forget to give the coil + some power) and then ground the housing.
In some cases the distributor may need a ground wire in order to function in the vehicle. I do this on any two-wire distributor, namely Accel and Holley ones.
The only other important aspect is the need for full voltage at the coil + terminal.
...The Tube
Ever noticed how powerful television advertising makes it self appear? I love the latest flock of Midas brake commercials that do little to justify purchasing their product.
Turn the sound down like most people do and watch the car run out of road in a panic stop. Then the freeze-frame and the road crew comes out and lays another twenty feet of blacktop.
Boy, I guess with every set of Midas pads you get your own personal road crew. I’d rather be able to stop.
GMC’s one percenters. That’s a crock. We would be only so fortunate if one percent of the population bought these excuses for real trucks. Their capabilities are just like the commercial shows…one end of the yard to the other..that’s it…blown up, overheated, better park the thing cause we ain’t gonna cover it!
Or that Ford 4WD LTD thing that the valet parks way out in the boonies cause he doesn’t want it to get scratched? More like he doesn’t want to get laughed at by the guy that owns the Hummer.
You Import manufacturers aren’t any more innocent than the rest....
Hi Stall
Recently a customer who owns a 455 cid F-body came by to purchase a torque converter from me. I asked him several questions in an attempt to find out why he was shopping for one, (my buddy told me so) and what the symptoms were that led him to the conclusion of converter replacement.
It turned out that the old one melted with the trans, (too much stall, too little gear), and he felt that there was something missing in the vehicle’s performance. I don’t care what the camshaft or compression may be, any V-8 that has 4.210” of stroke like the ’55 does is going to have little lacking in the acceleration department, unless you take some plugs out.
The dangerous thing to a street tired car is letting the motor unload for any amount of time longer than necessary. The customer wanted a 2800-rpm converter. 11” converter is what everyone might be saying to themselves.
I told him that it was way too much, and to think about the package a little more. 850DP, RPM, headers, hydraulic, 3.73, 3500lbs and a DOT sticky tire translates...
Don't Screw Up
Well it runs. What runs? My project, that’s what, and it runs quite well to add to all the labor and $$$ invested. And what difficulties did I encounter? Well none of them have been plumbing or fastening problems for sure.
The extensive use of aeronautical hardware in critical locations on my project is one aspect of ‘overbuild’ protection that I subscribe to. I am not saying that Detroit engineers were wrong in the selection of fasteners used to screw my car together. Many of those same fasteners are still there thirty plus years later.
However when servicing some of the more critical joints on ones project the re-use of fasteners should be carefully considered. This is most important when it comes to any kind of severe use, or when that extra margin of safety will allow you to sleep at night.Lets take a real world example to illustrate exactly what I am talking about. The lower control arm bolt. How many of you have ever considered replacing these when you had the front end apart in the driveway making a huge mess?
You went through all the...
FAQ on Shifters
Shifters You supply a 5’ long cable with all of your shifters. What if I want to use a shorter or longer one?
We have found that the 5 foot cable is most suitable for the majority of the installations. However B&M does offer cables from 2’ to 12’ lengths which may be purchased separately. See listing in catalog.
Why do B&M automatic shifters have two park positions? This is to accommodate the longer shift detent found in GM applications needed to engage park in those vehicles.
Can I use a B&M Super Duty race cable with any B&M shifter? Yes, except for the Unimatic shifter & Bandit. After installing the shifter in my car it became hard to shift because the cable melted on the exhaust.
What should I do to keep it from happening again? Secure the cable as far away from the exhaust as possible using tie wraps. Also, fabricate a heat shield out of thin sheet metal and attach it to the exhaust pipe with muffler clamps to act as a heat shield.
Why do the ratchet shifters allow you to ratchet to neutral? All B&M...