Put my new rims/tires on

takza · Post by **takza** » Fri Apr 16, 2004 4:34 pm

GTSSportCoupe wrote:Anyhow, after all this I have a choke that works really well, decent mileage, good power cold and hot, and a shitty idle (rough and loping).

I have that kind of idle as soon as I open my air bleed....which is a small amount of air bleed into the PCV line. I'd still think vacuum leak somewhere?

tercel4wdrules · Post by **tercel4wdrules** » Fri Apr 16, 2004 5:44 pm

GTSSportCoupe wrote: Everyone will have their own opinions, but I think its safe to say that within the world of minor-modified/un-modified Toyota A series engines, you are best off with the EFI variations (as far as all round reliabiliy, efficiency and power goes). Installing an EFI engine into an originally carbed car is a fair chunk of work, but will pay off for years if done well. If you are building a 4age race engine - carbs can be great (eg. Formula Atlantic 4age).

Back in the old days carburetors didn't have so much stuff added to them and were easier to work on (I think, correct me if I'm wrong) but I think were much crappier and fuel injection didn't exist in the early days. Nevertheless EFI is the future for cars and if anyone wants to "modernize" a Tercel 4WD by switching over to an EFI system then that person should, that's my opinion.

3A-C Power · Post by **3A-C Power** » Sat Apr 17, 2004 6:39 am

I'm going to EFI not because of the power, but for smoothness and refinement. The extra power is a consideration of course. The 3A-C carb has this unique feature where if you step on the gas below 3000 rpm, nothing seems to happen. Fuel injected cars that are running properly never display that characteristic. The get less power at lower rpms, but it is more like a progression from slow to fast. The 3A-C has this magic rpm where it starts to behave like an engine.

takza · Post by **takza** » Mon Apr 19, 2004 4:48 am

3A-C Power wrote:The 3A-C carb has this unique feature where if you step on the gas below 3000 rpm, nothing seems to happen. Fuel injected cars that are running properly never display that characteristic. The get less power at lower rpms, but it is more like a progression from slow to fast. The 3A-C has this magic rpm where it starts to behave like an engine.

I was going to ask this question........

Where do other people get this power boost? Mine starts in at around 2300-2400 RPM...and as far as I know, this is the secondary barrel opening up. Pretty sure that the RPM this happens at can be adjusted some.

For best MPG, you'd want the second barrel to stay closed for the most part when cruising. If you try to cruise at say 3000 RPM...you are going to be running partially on the second barrel....which is probably why some report poorer MPG if you try to run it above 55 MPH?

3A-C Power · Post by **3A-C Power** » Mon Apr 19, 2004 6:07 am

The secondary opens according to throttle and rpm. Mine seems to go on just below 3000 if I'm giving it lots of throttle.

takza · Post by **takza** » Mon Apr 19, 2004 8:30 am

Seems to be mostly vacuum controlled, with some mechanical linkage also. My second barrel kicks in at about 2300 RPM at maybe 2/3s throttle.

tercel4wdrules · Post by **tercel4wdrules** » Mon Apr 19, 2004 11:34 am

How do you know when your second barrel kicks in?

Typrus · Post by **Typrus** » Sat Aug 06, 2005 10:19 pm

He never got answered...
I wonder the same. When I push on my pedal, I get this part where I feel added resistance, about 2/3 the way down. Is this the mechanical linkeage part? Or is it a scalded monkey waiting to jump out of my engine once I get my problem fixed? lol. I need to cut back on the physical labor and coffee >.<

In my opinion, a properly tuned EFI will generate more raw power than a properly tuned carb. What is easier to "tune"? A carb. A carb can be taken apart, rejetted, and dropped back in by a person in their garage, with minor tools, if they have done it a few times before. EFI requires new injectors, new programming to go with said injectors, and a few other things. Thats not so easy.
What system is used in 7500 horsepower Top Fuel Dragsters? EFI. How much does a Top Fuel cost? I have no friggin clue but I imagine around $500,000. What does a backyard muscle-car drag enthusiast use? Carb. Cost? Well, if the car was bought recently from another owner then tuned, maybe $100,000, but if the guy had had it in the family since new and just fixed it up, maybe $40,000. What speeds are Enthusiasts hitting? 11's and slower. DAMN fast for Mr. Joe Average. What are TF's hitting nowadays? 3's? 4's?
A carb is reletively easy to soup up. EFI is not so easy.
You want to start right up, drive hard all day, and get good economy without spending a hefty sum? EFI my friend. You want a monster with great power and a (shivers in delight) B-E-A-utiful tone without massive expense? Carb it up.

As Fumes has shown us, its not impossible to change around if you go for the right system.

Diesel engines have been around for over 100 years. Diesels, by their very design properties, CANNOT be carb'd. They would pre-ignite ALL over the place, and have almost zero efficiency. They have to utilize fuel injection directly into the combustion chamber or a non-valved partition of it. Fuel Injection has been around for a LONG time. Just not Electronic Fuel Injection. And I don't think gas works in a mechanical injection pump, so FI has been a diesel thing for many years. Thats one reason why diesels are so efficient, along with the fact that they directly inject a premeasured amount of fuel directly into the combustion chamber, so there is near no overspray and waste. Timing is controlled by the injection point. Only thing the intake valve lets in is air (and in modern systems, EGR and CCV blowoff, which tends to clog the intake manifold). In modern systems, it just takes a single exhaust expulsion to tell the computer what to change in quantity or advance/retardation, so black soot is minimal in stock systems. In fact, in almost every state but Cali, catalytic converters are not required due to the sheer efficiency of combustion. I just wish gassers could work the same way.
Diesel has around 20,000-45,000 more BTU's of energy per gallon than gasoline. Thus given part of the increased efficiency.