Advanced Engine Theory and Design

[Mike Licht]

Here is a good book that I liked, Scientific Design of Intake & Exhaust Systems by Philip H. Smith and John c. Morrison Now it was written in the 70's and does not cover turbos but there is some very good info there on the pulse tuning topic
Mike

 

[Gentry]

HI Guys,
I'm new to the Buick community but I have a couple of questions that will certainly relate to engine theory.
We're building a car to run in this year's Bonneville event. The car will be powered by a 3.8 turbo v6. The problem is that electronic fuel injection is not allowed in this class, we have to run a carburetor.
I've ordered some books (turbochargers, HP Books) and will gather what information I can but the biggest problem, as I understand it, is that you can't run more than about 15 lbs of boost with a carb.

Does anyone have any experience with this?

 

[Alky V6]

HI Guys,
I'm new to the Buick community but I have a couple of questions that will certainly relate to engine theory.
We're building a car to run in this year's Bonneville event. The car will be powered by a 3.8 turbo v6. The problem is that electronic fuel injection is not allowed in this class, we have to run a carburetor.
I've ordered some books (turbochargers, HP Books) and will gather what information I can but the biggest problem, as I understand it, is that you can't run more than about 15 lbs of boost with a carb.

Does anyone have any experience with this?

I'll do a little research myself. Are you stuck on whether you will be using draw through or blow through? Using an aftercooler? What sort of intake manifolding to the heads? You do realize you will probably be dealing with distribution problems?

 

[Gentry]

Carb turbo

The rules are completely open in this class other than displacement and the fact we have to run a carburetor. We can do anything else.
I would think the blow through would be better than a draw through and I thought I'd run whatever good aftermarket intake manifold was available - preferrably a single plane.
I understand many people are using the belt-driven superchargers these days and many kits come with a box to put the entire carb in.
Using the belt-driven supercharger is certainly one method but I thought that, with all the technology already developed for the turbocharging systems in these Buicks that the turbo might be easier than a supercharger.
I thought I might actually run the stock-type '87 turbo setup including intercooler but instead of the pipe blowing into the EFI intake, I'd have it blow into one of these carb boxes. The carb boxes are sold through places like Summit.
Purchasing and using one of the '78-83(?) carb turbo engines seemed like a possibility but it doesn't appear that there's a good way to use an intercooler. You mentioned in your thread something about an aftercooler but I don't know what that is.
The plan would probably be to go have fun with a stock type engine, probably change the heads and cam. Maybe change to a higher-performance engine or a Stage engine for the next year.

 

[Alky V6]

Sorry for the change of term on you. Intercooler is the 'popular' term. The 'proper' term is aftercooler.

If you're looking for a maximum efficiency blower system, nothing beats a turbocharger system. That is the plain, hard truth. You're tapping into the 30 some odd percent of power that the engine generates, then expells out the exhaust pipes in the form of heat energy. That is almost totally free energy to turn your blower. Back pressure caused by the turbocharger system does take some power.

To run a belt driven blower, you must generate extra power just to turn the blower before you see a benefit, while still even more free energy is expelled through the exhaust system. The only benefit I see with the belt driven blower system is ease of installation.

I agree that the blow through would be better. Especially if you were to have an intake backfire.

 

[Alky V6]

Ok, I'll bite...what is "Pressure Pulse Tuning"? Anything to do with the length of the intake runners and the movement of the peak torque up or down the RPM scale? Corky Bell's book talks about the optimum size of the intake plenum. What is the theory and calculations?
Conrad

Refer back to page 3 of this thread. If you stills have questions, let me know and I'll try to answer them.

 

[Alky V6]

Here is a good book that I liked, Scientific Design of Intake & Exhaust Systems by Philip H. Smith and John c. Morrison Now it was written in the 70's and does not cover turbos but there is some very good info there on the pulse tuning topic
Mike

Any book that touches on the subject of 2 stroke engine tuning should have a good section on pressure pulse tuning. It is a very, very important tuning tool for 2 strokes. Check out 'Two-Stroke Performance Tuning' (2nd Edition) by A. Graham Bell. ISBN 1 85960 619 9

 

[XxDarkSidexX]

Any book that touches on the subject of 2 stroke engine tuning should have a good section on pressure pulse tuning. It is a very, very important tuning tool for 2 strokes. Check out 'Two-Stroke Performance Tuning' (2nd Edition) by A. Graham Bell. ISBN 1 85960 619 9

droppin the knowledge you da f'ing man DON!!!! Your post is owning! Great reading.

 

[ijames]

The rules are completely open in this class other than displacement and the fact we have to run a carburetor. We can do anything else.
I would think the blow through would be better than a draw through and I thought I'd run whatever good aftermarket intake manifold was available - preferrably a single plane.
I understand many people are using the belt-driven superchargers these days and many kits come with a box to put the entire carb in.
Using the belt-driven supercharger is certainly one method but I thought that, with all the technology already developed for the turbocharging systems in these Buicks that the turbo might be easier than a supercharger.
I thought I might actually run the stock-type '87 turbo setup including intercooler but instead of the pipe blowing into the EFI intake, I'd have it blow into one of these carb boxes. The carb boxes are sold through places like Summit.
Purchasing and using one of the '78-83(?) carb turbo engines seemed like a possibility but it doesn't appear that there's a good way to use an intercooler. You mentioned in your thread something about an aftercooler but I don't know what that is.
The plan would probably be to go have fun with a stock type engine, probably change the heads and cam. Maybe change to a higher-performance engine or a Stage engine for the next year.

I think a stock longblock 86-87 would be a good foundation. Stronger than earlier engines and the front turbo location and serpentine belt setup and electric radiator fan make intercooler plumbing much easier. You don't mention what body style, but don't bother with the stock intercooler, go with a frontmount from the start if you have the room to keep the charge air hitting the carb as cool as possible. Either the Ford powerstroke setup that lots of guys fabricate for themselves or one of the good aftermarket frontmounts. Swap the intake manifold for either a stock 4 bbl one from a 4.1 or one of the buick aluminum ones. Get it running and learn how to tune it, then think about better heads and a cam. Give us some hp and rpm targets and we can suggest turbo and cam combinations.

 

[Alky V6]

Gentry. I ran across a book that would be a good primer for you.

A Do-It-Yourself Guide to:
Street Supercharging
How to Install and Tune Blowers

S-A Design
by Pat Ganahl

It has a good section on blowers with carbs. A blow through doesn't sound easy at all. Thank God for EFI. Best advice would be to find someone who has a bunch of experience setting up carbs for blower applications.

 

[Alky V6]

I came across an interesting article. Some very well documented builds on the EcoTec engine. The recommendations are very applicable to our situations. Enjoy.

http://www.gm.com/company/gmtunerso...er_600hp_control_systems_and_torque_specs.pdf

 

[Alky V6]

I know there is a growing number of individuals that are starting to map their own fuel and ignition tables. I want to cover initial mapping of fuel and ignition tables at some point, but until then I'll throw out some tuning tips every now and then.

Work on fine tuning the ignition table AFTER you have dialed in the fuel map.

In each cell of your ignition timing table, always aim for the least amount of timing that will give you the most power. In some cases there may be a window where the power will stay the same as you increase timing. Always use the smallest amount of ignition advance necessary to maintain a maximum HP number. There is nothing impressive about running more advance than you have to.

The rule is MBT (minimum best timing). Following this rule will give you a nice cushion against detonation.

 

[Alky V6]

I'm going to make this easy and recommend a book.

Engine Management - Optimizing carburetors, fuel injection and ignition systems. Author, Dave Walker. Publisher, Haynes.

This book has a fantastic section in it that simply explains the steps that should be taken when first setting up, and tuning in a new engine with a total control engine management system.

I've had the book awhile now and just recently read over the section I mentioned above. It follows a logical path and gives basic suggestions and tips that follow the thinking and procedures I eventually taught myself after months and months of dealing with my own project. If your new at engine management tuning or just want to look at a different perspective of procedures, I highly recommend you look into this book. It follows a very logical and methodical path. And gives some very basic hints on fueling and ignition timing stradegy that you don't learn without a ton of experience. He performs his tuning on a chassis dyno, but it is easy enough to get around that and still follow his tuning strategy. I did it.

 

[Dusty Bradford]

HI Guys,
I'm new to the Buick community but I have a couple of questions that will certainly relate to engine theory.
We're building a car to run in this year's Bonneville event. The car will be powered by a 3.8 turbo v6. The problem is that electronic fuel injection is not allowed in this class, we have to run a carburetor.
I've ordered some books (turbochargers, HP Books) and will gather what information I can but the biggest problem, as I understand it, is that you can't run more than about 15 lbs of boost with a carb.

Does anyone have any experience with this?

You need to be on turbomustangs.com in the carb/blow thru section. Guys are flying with blow thru carbs. They are as fast as efi in some cases with 6 and 7 second passes. CSU seems to be the guys to deal with and with the 7531 MSD box you tune and control timing with a MAP so you get EFI like timing control over your carb'd motor.

15psi is a joke. You can run as much as your motor can take. There are bonnets for the carb so no need for a box around the carb.

 

[Dusty Bradford]

Here's a link to a nice carb set-up

http://www.turbobuick.com/forums/turbo-v8-conversions/204531-progress-pics.html

 

[Alky V6]

Thanks for the help Dusty.

 

[Alky V6]

Engine Oils

I want to layout some interesting things I learned recently. I know there are some threads that may have discussed this, but I want to make sure the knowledge is well circulated so that people can make changes to their routine if needed.

For some time now, the oil companies have been pulling out certain additives in their engine oils to comply with emissions needs. It seems that some of the additives adversely affect oxygen sensors and catalytic converters. Unfortunately, some of these additives that are being removed are EP (extreme pressure) additives. One in particular is zinc. It appears there was a master plan set into motion over 10 years ago to eventually pull enough of these additives out of the oil to keep catalytic converters and oxygen sensors lasting 100,000 miles. Why? Well, since the auto manufacturers are required to warranty smog equipment for 100,000 miles, it makes sense that they would do whatever it takes to keep those components alive for the warranty period. The widespread move to roller valve train components was a move towards the eventuality that EP additives would be at lower levels in the near future. It appears that within the last year or so, the levels have reached a dangerous level for people still running older engine designs using flat tappets. The talk is buzzing at engine shops and cam manufacturers about the upswing of cam failures. There are some important things to do to keep your cams alive with todays oils.

 

[Hot Air]

I have heard that Shell Rotella Diesel still has the additives. I know that Comp Cam recommends that it be in the oil pan whenever breaking in one of their flat tappet cams.
Conrad

 

[Alky V6]

Some of the additives available to enhance off the shelf oils that I know of:
BG's MOA additive.
GM's EOS additive.
Racing only oils.
Prolong additive.
The new Mobil 1 WITH the enhanced additive package. Check the label.
Diesel engine oils, as was mentioned. Rotella T and Chevron Delo 400.

Other questionable sources:
Lucas oil supplement.
Some of the Schaeffer oils.

Generally, you can expect the very light (5w-30), off the shelf oils to have weak EP additive packages.

 

[GARY HARVEY]

Some time ago, I went to the local GM stealership and came home with a case of their additive.
My trip was made after a visit with a friend that is a Exxon tribologist (sp) here in Houston. By the way, did you know Exxon owns/makes nearly all of the additive packages used by the major oil producers.
Zink IS becoming a scarse commodity in typical oil brands. Mobil 1 extended drain is supposed to have zink (i was told). I use Royal Purple with the GM additive in the T.
Rotella T and Lucus has been in my Ram for 250,000+ (36,000 lbs. gross) and the VT shows very, very little wear. The Texas Garage Owners Assoc. keeps up with this sort of thing and their membership suggests using Rotella FWIW.