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Discussion Starter · #1 ·
I have a fairly broad understanding of engines and their components, but don't work on them often at all. What are some relatively easy modifications that one could do without getting themselves into a lot of trouble, but still getting some performance increase and experience?
 

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Where do you draw the line at what you'll do and what you'll pay someone to do?
 

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Yeah. I can give detailed instructions on how to port your cylinder head. Some guys would get it and do it right. Others would just make a good thing bad. It's all about where you draw the line between what you'll do and what you'll pay to have done. For instance, I pay to have alignments done. I can do it myself, but I haven't invested in the equipment to do it right, and I know someone who has. It would be dumb for me to do it myself. Not so cylinder head porting. I have the tools and experience to know I'll have something better when I'm done. That's the real differentiator for me.
 

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Originally posted by lo bux racer@Oct 18 2005, 11:10 PM
Yeah. I can give detailed instructions on how to port your cylinder head. Some guys would get it and do it right. Others would just make a good thing bad. It's all about where you draw the line between what you'll do and what you'll pay to have done. For instance, I pay to have alignments done. I can do it myself, but I haven't invested in the equipment to do it right, and I know someone who has. It would be dumb for me to do it myself. Not so cylinder head porting. I have the tools and experience to know I'll have something better when I'm done. That's the real differentiator for me.
If you ever get bored, write that up. I have the access to the tools through my stepdad, he builds drag-cars for a living... He wouldn't know his way around our new engines, he's old school chevy kinda guy.

Would a port job be a standalone mod in essence? Wouldn't the gain come from the ECU compensating for a better flow?
 

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Essentially, yes.
 

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Well, without writing it all up, you have a website in mind that explains the process? What parts you think would benefit the most?
 

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Start here. This talks about the basics, and Standard Abrasives is the most used abrasive manufacturer in the porting world.
 

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Discussion Starter · #9 ·
What i mean beyond that, though, is what suggestions you have for joe scion owner who may not want to send out the car or spend a lot but would like some simple projects to improve the car. preferably not porting the cylinders.
 

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There is nothing simple to improve engine performance without violating a host of federal and possibly state laws, even then most "improvements" are not real improvements.

There are a number of mods you can do to the chassis that significantly improve handling, but these require some significant tools and quite a bit of effort, not to mention you are best off to start with better tires (and wheels IMHO) to really make a difference.

Sorry, there are no quick and easy jobs that will make anything like a seat of the pants difference in the tC's performance.
 

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It's not cost effective. Precision casting (better than what they are doing, which is a lot better than 20 years ago) is expensive. Hand finishing heads is expensive (but Honda claims they do this to the Type R Integras) on a production basis.

Would you pay another $500 for 3 - 5% more power?
 

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Do you think the results would be worth the effort Lobux, of porting the head?
 

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That's been my experience. I usually get about 8% more power. That would be 173 hp fromt the 2AZ with no change in efficiency or smog legality. I'll take that.
 

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what exactly is porting your cylinder head..err i guess i should do a "search" :[
 

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An engine is an air pump. If you want to make more power with the same sized pump, you need to make it ingest more air. The two ways of doing this are improving it's breathing efficiency and shoving air in forcibly, wether by mechanical or chemical methods.

If you are going to forcably induct it, then start working on the breathing efficiency. Toyota did a pretty good job with the engineering, so the first and easiest places to start are where you think the company would compromise performance and cost. Places that come to mind are the intake and outlet of the motor. Essentially you are making the engine breather easier.

Be careful with cylinder head work. Air is a picky fluid and too much adjustment to the passage can reduce the actual flow in a motor. Specifically in a normally aspirated motor, air velocity and high-lift air flow are more important than the pure volume of air flow capacity at any given moment. The air is traveling across a very inefficient valve system (the single biggest loss in efficiency in a motor, even moreso than heat) and does not take a path anywhere near linear; as such the shape of the port and the thorat and seat area are extremely picky and an inexperienced hand and a die grinder can do more damage than one might expect. If you are not a professional or experienced in the real-world effects of port shaping, I'd stick to the "polish" half of port and polish. A good bit can be gained simply by cleaning up the castings and port areas and making the airflow smooth and uninterupted. It certainly is not an exact science. At least one a mortal could afford to model, or do with a die grinder for that matter.


Standard abrasives is pretty much THE name in automotive abrasives, as lobuxracer said. Just don't go crazy.
Also, make it breathe better before you make it breathe more!

If you want to gain power other than improving the moderations of economy required to sell such a car to such a market, then you will either have to (not preferably) break some laws, improve the design of a certain component, or upset the balance in the engine's performance. What I mean by that is you can add XXX mod and get 5hp peak but lose 5ft*lb in the 2000-4000RPM range. This isn't desirable for some applications, but if peak power is what you are looking for than it may be a good thing. Getting a free and overall gain is, as said before, a matter of improving the engineering or moving beyond the law-based design specs for a certain mechanism.

Obviously we all have to live with legal restrictions as far as emmisions and the equipment securing it's ensurance, but you can legally tweak a part here or there to get a few 'extra ponies'.

"Beginner mods" then. I would also like to back up the chassis tuning part. If you don't mind the downsides of a sportier suspension then improving the mchanics there can make the car feel a lot better. Akin to this, I'd like to mention that a well-trained limo driver can make the people in the back feel like they are speeding when the hypothetical Mr Collinsworth says "Step on it James, we're late for the ball" by applying the brakes more sharply, using more throttle and turning in smaller radii later. He doesn't actually have to break the speed limit!

Back on topic (again) getting a nice exhaust and intake system can improve the acceleration and top end of the car, and in rare cases the low-end if the said modifications take this factor into mind (few do). Those are typical first mods and they are good ones.

One last little tidbit: unspring weight is the bane of a car's performance, specifically in stopping, accelerating and turning. Working on that can make the car a lot more fun to drive.
 

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Originally posted by SK VR4@Oct 19 2005, 09:37 AM
An engine is an air pump. If you want to make more power with the same sized pump, you need to make it ingest more air. The two ways of doing this are improving it's breathing efficiency and shoving air in forcibly, wether by mechanical or chemical methods.

If you are going to forcably induct it, then start working on the breathing efficiency. Toyota did a pretty good job with the engineering, so the first and easiest places to start are where you think the company would compromise performance and cost. Places that come to mind are the intake and outlet of the motor. Essentially you are making the engine breather easier.

Be careful with cylinder head work. Air is a picky fluid and too much adjustment to the passage can reduce the actual flow in a motor. Specifically in a normally aspirated motor, air velocity and high-lift air flow are more important than the pure volume of air flow capacity at any given moment. The air is traveling across a very inefficient valve system (the single biggest loss in efficiency in a motor, even moreso than heat) and does not take a path anywhere near linear; as such the shape of the port and the thorat and seat area are extremely picky and an inexperienced hand and a die grinder can do more damage than one might expect. If you are not a professional or experienced in the real-world effects of port shaping, I'd stick to the "polish" half of port and polish. A good bit can be gained simply by cleaning up the castings and port areas and making the airflow smooth and uninterupted. It certainly is not an exact science. At least one a mortal could afford to model, or do with a die grinder for that matter.


Standard abrasives is pretty much THE name in automotive abrasives, as lobuxracer said. Just don't go crazy.
Also, make it breathe better before you make it breathe more!

If you want to gain power other than improving the moderations of economy required to sell such a car to such a market, then you will either have to (not preferably) break some laws, improve the design of a certain component, or upset the balance in the engine's performance. What I mean by that is you can add XXX mod and get 5hp peak but lose 5ft*lb in the 2000-4000RPM range. This isn't desirable for some applications, but if peak power is what you are looking for than it may be a good thing. Getting a free and overall gain is, as said before, a matter of improving the engineering or moving beyond the law-based design specs for a certain mechanism.

Obviously we all have to live with legal restrictions as far as emmisions and the equipment securing it's ensurance, but you can legally tweak a part here or there to get a few 'extra ponies'.

"Beginner mods" then. I would also like to back up the chassis tuning part. If you don't mind the downsides of a sportier suspension then improving the mchanics there can make the car feel a lot better. Akin to this, I'd like to mention that a well-trained limo driver can make the people in the back feel like they are speeding when the hypothetical Mr Collinsworth says "Step on it James, we're late for the ball" by applying the brakes more sharply, using more throttle and turning in smaller radii later. He doesn't actually have to break the speed limit!

Back on topic (again) getting a nice exhaust and intake system can improve the acceleration and top end of the car, and in rare cases the low-end if the said modifications take this factor into mind (few do). Those are typical first mods and they are good ones.

One last little tidbit: unspring weight is the bane of a car's performance, specifically in stopping, accelerating and turning. Working on that can make the car a lot more fun to drive.
Wow you really know your cars!! keep up the good info to help us "kids"
 

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Originally posted by SK VR4@Oct 19 2005, 09:37 AM
Be careful with cylinder head work. Air is a picky fluid and too much adjustment to the passage can reduce the actual flow in a motor. Specifically in a normally aspirated motor, air velocity and high-lift air flow are more important than the pure volume of air flow capacity at any given moment. The air is traveling across a very inefficient valve system (the single biggest loss in efficiency in a motor, even moreso than heat) and does not take a path anywhere near linear; as such the shape of the port and the thorat and seat area are extremely picky and an inexperienced hand and a die grinder can do more damage than one might expect. If you are not a professional or experienced in the real-world effects of port shaping, I'd stick to the "polish" half of port and polish. A good bit can be gained simply by cleaning up the castings and port areas and making the airflow smooth and uninterupted. It certainly is not an exact science. At least one a mortal could afford to model, or do with a die grinder for that matter.
I would only differ with this by saying there is much more to be gained by focusing on low lift flow. Big peak numbers look good, but nothing beats a 3 - 7% increase across the board from getting the low lift flow right. Low lift numbers affect the entire duration of the cam, where peak numbers only mean something for about 10 degrees or so depending on the grind.

The key advice I would give the junior head porter is leave the carbides in the box. Do everything with cartridge rolls. It will be a lot slower, but you'll get a feel for what it is you want to achieve without terrorizing the head in a few seconds. One bad move with a carbide bit and the head is scrap metal. If you leave the carbides alone and focus on making the existing ports free of sharp edges and turns, unshroud the valves at the edge of the combustion chamber, and remove all sharp edges from the combustion chamber, you'll get everything the factory intended and a little more.

FWIW, polish is a poor word to describe the finished surface. Intakes should be a little rough to discourage fuel from forming droplets on the walls. Exhausts can be fairly polished, but a mirror finish is what a lot of guys use to hide their mistakes. You can have a beautifully mirrored finish and have the port walls so wavy that they flow worse than rough cast and you are hard pressed to see it unless you know exactly what you're looking for.

It's also critically important to understand some key relationships between cam grind, rod length/stroke ratio, and port cross section. There are a number of (thankfully) inexpensive programs you can buy to evaluate these things with computer models instead of committing them to metal before you test.

The other huge plus to port work is that everything you do to increase flow after you've done the port work gets the same bump. So if you add forced induction after getting a 25% flow improvement, the forced induction will also see a 25% gain. It's one of those, "you just can't lose deals."
 
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