I highly recommend a little reading assignment for some of you guys.

Maximum Boost
by Corky Bell

He explains in detail how doubling the output power with forced induction only results in 20% more load in the most critical part of the power stroke. This is not speculation, all the formulas, etc are explained in detail. The added load is compressive in nature and not the most the most important aspect of engine design.

Inertial loads, which are not much of a factor if at all in adding FI to an NA engine, are critical aspects to consider when designing any piston engine. Over revving due to missed shifts or raising the rev limit are far more damaging than FI could ever be. As an example raising the rev limit from 6k to 7.2 k results in a 144% increase in inertial loads wether or not FI is added.

BAD tuning, over revving, improper heat management, poor maintenance, etc, kills far more FI engines than adding a reasonable amount of boost ever will.

Rick

 

I've heard Corky Bell is the sizzle for boost information. I need to hit the library and check it out.

 

Tiz the bible for turbocharging.

 

The book is a bit old now but the engineering is still the same, best thing I ever read about making some fun power. I will be a die hard turbo guy all my life now that I really understand what is going on with being boosted(I have owned this book for a number of years;)

I just updated the info a bit, added inertial load issues.

Rick

 

GJ

 

 

Just what little I know about 'forced induction' agrees with this. It stresses engines more, just not to the extent that it should cause damage - BUT it allows/supports/encourages OTHER behavior that can easily damage an engine.

(Now, about the subject line, Rick - 'back in the day' we often referred to those big GM rootes type superchargers (like the 6/71s
or 8/71s) sticking up out of the engine bay as "blowers" and it was common to say that an engine with a 'blower' on it was 'blown.' Totally different use for the word historically. )

If course, some of those blower setups were, uh, bigger than our entire engine compartment...

 

I am reading it, and its the best 20 bucks i spent on a used book.

 

hey tomas is that a pic of you working on an old car of yours?

 

Main factors with blown motors is driving style, horrible maintenance, over-rev, and tuning.

Also causes can be putting too large of a turbo with high psi levels on a motor that logically cannot handle the levels.

For instance: 1.8l stock, throwing on 20psi turbo. Now, this motor will blow, it won't last, tranny will give out and the main reason for this would be the f/i set up.

Not only do you have to keep up with maintenance and drive in a mature fashion, but you also have to use a great deal of common sense. Most n/a motors, infact 90% of all n/a motors (for that matter) are not designed to be boosted. If they were, 90% of the time they will have f/i from the factory. With that said, prep-build/work should be, and in some cases has to be recommended for the life of the motor and trans. In most cases, its just simple work because most aren't running a very high psi on street driven cars. But doing this will allow the motor to run more cleaner, put more power to the ground, run less of a chance of running too lean or too rich with a proper tune and so on.

Telling people to go read on here is like telling a 10 year old to study. Most aren't going to do it. Why? Lazy. You have to tell them on here, no offense to anyone but its the truth.

 

90% of vehicles would simply not come with FI no matter how well they were set up from the factory. In fact, many manufacturers that sell a turbo version of their motor, also sell an NA version. This is because of marketing concerns, emissions concerns, and overall drivability compared with expectations. In fact, only about 3% of cars sold have forced induction to begin with. You need to realize that a Toyota Camry wouldn't be FI if it came with a perfect 8.5:1 compression ratio, and had a hand built forged internals engine with a ported and polished cylinder head. People don't buy them to go fast, they buy them to get from point A to point B. This is true of most cars sold.

 

Killer and Single,
This thread is not about what ever reasons the manf decides to turbo thier particular cars or not, nor how they build them if they are designing to be boosted. You both make some good points but a bit off topic.

All this thread is about is what damages an engine when boosted and within a resonable amout of boost, what the real culprits are that cause the vast majority of NA to FI conversions to fail. Those things being mentioned already on the first post.

That is it, do things right and you can safely raise the power output of any NA engine, within limits of the design of that particular engine of course. It has already been proven the 2AZ can produce a great deal of power in the 15-20 PSI range but not advisable, in the 10 and maybe as high as 12 PSI range there should be no long tern ill effects other than possibly just plain wearing things out 10-20% sooner. Since the 2AZ is an exceptionally well built engine, that means ALOT of miles down the road.

Moral of this story, do not be afraid of the big bad boost, just use some common sense and the right parts and tuning and you will be just fine;)

Rick

 

Very good book, I would recommend this as well Good thread raamaudio.

 

This is a great thread and great info. We are running 15psi pn our stock tC and racing the crap out of it without incident but with a great tune.

We see N/A guys blowing up. Properly caring for your car will allow you to run more boost and longer. It goes back to the guys who rush the install are never happy but the guy who takes his time has nothing but good things to say. They both install the same parts on the same car.

99% of all issues and internet myths are from some of the reasons listed in this thread. The biggest problem is that noone ever comes on auto forums and says i screwed up and installed a line wrong and blew my car up. It is always the parts are wrong etc...


These are great books and knowledge that any novice tuner should at least skim through to learn the basics of what is fact v. forum fiction.

 

With ZPI's experiences as an important example of what can be done with proper tuning I may be overly conservative with my long term reliability estimate of 10 PSI, 12 upper limit. It is probably a bit higher yet as long as your fuel has high enough octane.

Rick

 

Corky is a genius. True story, I've seen his engineering first hand.

 

I have to pipe in here and say a few things.

There is always a right and a wrong way to do things. The best advice is always read up on what your doing and take your time before you act.

I know a person that is running a 96 Toyota truck that has been turboed for many many years now. He curently has over 150k miles on it with no problems.
This truck is used for rock crawling but for the most part is a stockish truck.
He did read alot about it and knows more then most people I know about turbos and what to/not to do.

All I can say is read everything you can and talk to as many people as you can that have had experiance with modding engines.

Looking for this book this weekend....

 

I have a 96 Tacoma that was had an SC but it was not the best setup, TuRD is what I called it at the time. But it sure pulled a heavy load, insanely so, many times. Just did not have much more pep driving it around.

It has had a rough and interesting life, been hit and run many times and fixed, 7 page feature article in Mobiel Entertainment Magazine in 2002, 160k hard miles, still runs like a champ and only a few minor repairs ever. Not one time did it fail to get us where we were going, 7K snow cover mountain pass, 121 degree desert, keeps on ticking.

It need some love now, going to freshen things up a bit and paint it again, then build a low boost turbo system for it

Rick

 

I'm going to have to check this one out.

 

great info but there will alway's be people who will overbost or do a bad tune job then blame every body else for there blown motor than try to get the factory to cover thr repair's after they pull all the after market part's off. that is why so many people are afraid of the turbo.