SR5 - 4A-C engine

[Mux213]

Ivan,

You are forgetting taking the stock carberators off and putting some nice webers on them

Really, just take a look at the paradise racing site, there is alot more to be had for the 4AC than you think.

It just never will be fuel efficient

And yeah, I guess when you got the 4AC running with that gear you would have spend more then buying a good second hand 4AG. If you have the tools, room and knowladge to do the swap yourself and forget about the rear axle mods, brake mods, suspention mods, etc, then it probably wont make much difference.

But if you have to let someone do the swap for you, hell you'll spend a whole lot more $$$ then tuning a 4AC

Then again, I dont have any hands on experience with the 4AC, I'm just going on what little knowladge I do know about carbed engines. With carbed engines having some good carberators can make all the difference in power especially compared to stock where fuel efficiency was more on the minds of the manufacturer then power.

Jamie, owh I thought from his site that he was doing a turbo on a 4AC. Well I dont speak the language so....

[The Doctor]

mux213 Wrote:Ivan,

You are forgetting taking the stock carberators off and putting some nice webers on them

Webers are nice, but imho Solex/Mikuni's (The ones Toyota uses on 18R-G, 2T-G and lots of others) are just as good and not so freaking expensive!

[Mux213]

The Doctor,

Hehe I saw what Mikumi's can do on a rotary engine a 110hp 12A from a friend of mine ran around 150hp with mikumi's and another exhaust header

Then again, rotaries are much more sensative to these kind of changes then piston engines..

[NoHachi]

Quote:You are forgetting taking the stock carberators off and putting some nice webers on them

Quote:The way to tune the 4AC is by:
Wilder cams
Better carbs or probably just a rejet from the current ones

What I'm saying is: just slap those webber mikuni, solex whatever (they're all weber dcoe copies) onto a 4A-GE and you just lost a lot of the wiring troubles. The rest of the swap is just peanuts. Throw in a wild bunch of cams a you're looking at 160+horsepower and a far nicer powerband.

Its not all that easy though. Setting up carbies is a lost art and not that easy at all. I would prefer the wiring mess I think.

[alimonos]

Nohachi we tried a carbyrated 4age in a Starlet and it had less power than the tvis base configuration man!
Of course we didn't change any cams as you said...
The solution you wrote is tested? writeup details about cams and carbs... :wink:

[Mux213]

NoHachi,

Hehe putting carbs on a 4AG would be very interesting aswell indeed. Simplyfies the swap a whole lot.

Alimonos, its what NoHachi (or Ivan taking over his PC, dunne know) is saying, carberator tuning is a lost art. Also I wonder if a 16v head with cams designed with an EFI in mind is the best combo. The thing is, an EFI can control different fuel/air ratios depending on RPM and other engine vitals. Combine this with how 16v improves airflow over the RPM range you have an engine with much more power over a larger range while still being fuel efficient.

A carb has a fixed setup and really is targetted at a certain RPM at which the mixture is optimal and power is greatest but at other RPMs you are dumping way to much fuel into the system. Or if you want fuel economy you simply can't reach that max potential of the engine (which is why I think a 4AC has more potential then you might think). Well atleast thats how I understand it, I am far from an expert on this subject, more or less repeating what I've learned from websites and people

The thing with carbs is though that once you know how, they are alot easier to tune, no complex electronics to worry about, just a few screws that you can turn to adjust the mixture and away you go

My dad used to tinker with old Fiats when he was in his late teens, early twenties and got some very nice results putting hi performance carberators on these engines and playing with the settings But in the end there is a reason why all cars use EFI these days

[The Doctor]

it's pure economics, you can't get passed EURO3 norms with a carb engine.

EFI is nice, but carbs make such a nice sound and are pretty good in what they are designed for
Only, the big environmental problem is starting a carb engine, thats where the problems with the Euro norms are

[Mux213]

Doc,

Exactly, and that is a result from a carbed engine using way more fuel that does not get burned properly.....

So either you have an engine with little power, or an engine that is very fuel hungry. EFI helps solve that