diferences

shogun · Post by **shogun** » Tue Jun 07, 2005 9:10 am

im thinking of going hybrid, 4ac block with all the goodies i can find and afford and a 3asu head, so what things can be used in both engines, the pistons i know i cant use in my stock one

GTSSportCoupe · Post by **GTSSportCoupe** » Tue Jun 07, 2005 9:20 am

AFAIK the only difference of significance between the 3AC and 4AC is the bore of the 4AC is larger (giving 100cc more displacement).

The 3ASU head should bolt on the 4AC no problem at all. Sounds like it'll be a great setup. You could use a 7A bottom end too if you wanted even more torque.

shogun · Post by **shogun** » Tue Jun 07, 2005 1:30 pm

the thing is i{m turbocharging the whole thing 4a block with turbo pistons and a 3a su head with the works, minus schneider cam, that will be untill i get enough money, fuel delivery is from a holley carb and rising rate fpr

GTSSportCoupe · Post by **GTSSportCoupe** » Tue Jun 07, 2005 2:06 pm

shogun wrote: the thing is i{m turbocharging the whole thing 4a block with turbo pistons and a 3a su head with the works, minus schneider cam, that will be untill i get enough money, fuel delivery is from a holley carb and rising rate fpr

Try to get ahold of a 4age/ze/20V bottom end that was made between 1990-1995. These bottom ends all share the same crank and rods, and are capable of holding up to in excess of 350hp. Obviously the pistons are different per revision, and you are using an 8 valve head anyhow, so you will have to get custom low comp forged pistons.

I believe the 4afe bottom end over the same period is also much stronger. I know the block is shared with the 4age/ze/20V, but I'm not sure about the crank/rods.

Sounds like a neat project!

shogun · Post by **shogun** » Wed Jun 08, 2005 10:28 am

thanks, im not doing a lot of boost, 6psi to be exact on 95 octane gas and 9 on c16 racing fuel, i found forged pistons, but i dont have the money to boy the whole thing, i will try with the sock block, ive made the calculations with a friend of mine that is a toyota engineer, and that are the figures we came out with

GTSSportCoupe · Post by **GTSSportCoupe** » Wed Jun 08, 2005 11:11 am

shogun wrote: thanks, im not doing a lot of boost, 6psi to be exact on 95 octane gas and 9 on c16 racing fuel, i found forged pistons, but i dont have the money to boy the whole thing, i will try with the sock block, ive made the calculations with a friend of mine that is a toyota engineer, and that are the figures we came out with

Sounds awesome! Can't wait to hear how it works out.

shogun · Post by **shogun** » Wed Jun 08, 2005 3:52 pm

that is my hopes, i was the first one in guatemala to have a twin carbed tercel4wd, then i was the first with a 48 idf in it, now im guing turbo cant wait until i have the money

nathan fisscher · Post by **nathan fisscher** » Thu Jun 16, 2005 8:54 pm

what about the 4a_e motor

tercel4wdrules · Post by **tercel4wdrules** » Fri Jun 17, 2005 9:36 pm

I'm also interested in doing a simple turbo setup, too, but to me it would be a little overwhelming and I'm just preparing my basic research for now. That way when I have money all I need to do is just take my research and planning and carry it out. In fact, I know of a fellow who turboed a 3E carbureted and converted to EFI and I believe he was running on stock internals. He just added an intercooler and ran it at a moderate-low psi. It wouldn't hurt to weld some ribs on the block for reinforcement. Good luck on your project. It's going to be spectacular and I hope you document it from beginning to end.

shogun · Post by **shogun** » Sat Jun 18, 2005 9:39 am

welding to your block can cause it to bend and create stress were there wasn{t any stock internal in the 3ac can hold up to 8psi in 95 octane gas with propper jetting of the carb, im going for a webber 32/36 with special viton gaskets for boost and rejetted to work with boost i have a toyota mr2 sw20 intercooler, and a tc04 mitsubishi turbo from then on the only thing im buying new is the rising rate fpr

tercel4wdrules · Post by **tercel4wdrules** » Sun Jun 19, 2005 4:11 pm

Good point, I guess I know why cast iron is such low in quality. So, what can you do to increase strength?

GTSSportCoupe · Post by **GTSSportCoupe** » Sun Jun 19, 2005 5:42 pm

tercel4wdrules wrote: Good point, I guess I know why cast iron is such low in quality. So, what can you do to increase strength?

Cast Iron isn't low quality, it's just not possible to weld because of the internal structure of the iron (having gone through a casting process). It is brittle and almost crystallized.

Pretty much all Toyota iron blocks can handle a heck of a beating though. You really only have to worry about pistons/rods/crank/head gasket. Running correct fuel mixture and ignition timing is CRUCIAL in a turbo setup. Especially if you are not using tough internals. If you run a lean mixture or advance your timing too much, be prepared to melt a piston, or punch a hole through it. Using a thicker head gasket is a great way to decrease your compression without swapping in low comp pistons (for a budget project).

Work with an engine that will allow you to meet your goals. There are many 'a' engine options. If your goal is around a 50% gain, you could probably work just fine with a 3ac. Or, you could swap in a reliable unmodified 'a' series engine with the same amount of power (4age). If your goal is a 400% power gain, work with a 4agze.

shogun · Post by **shogun** » Mon Jun 20, 2005 4:47 pm

build a girdle for the main caps, that is basically what youcan do to the block, then set up the limits of your engine and run 25-30% below that just to be safe

Typrus · Post by **Typrus** » Sun Sep 11, 2005 2:50 pm

Heh. Yay for older topics.
What are the different engine options for lower end power? Maybe 100 horses at the same RPM the 3AC gets its peak of 62?
What is there that will kick out high-end power? I almost immediatly think of a 4AGTE, but what else?
Does anyone know much about the "F" series engines? 5AFE, 4AFE... Where is their torque and how much is it?
G Series? Where is the torque and how much is it?

What can be done to the "C" heads? 3AC/4AC. I know the 4AC can take a heck of a beating in the power department with GE internals, but I know the heads are... Limited, shall we say. Lack of cross-flow valving, 2 valves per cylinder, low RPM engine... What can be done to help this, or what can be set on top of the 3AC block? What will the 3AC block take?

How about 6 cylinder engines? Just how impossible is it to think about a Supra inline 6? Those engines are in-f'ing-credible when it comes to power handling, I know that much. I just don't know how heavy they are, how they mount up, how much custom work would be required to put in the Supra's tranny and rear axle (For a dedicated RWD setup) I'm curious if the nose would have to be pushed out a bit (I imagine it would, as the I-4 comes pretty close) And to what degree would the body need reinforcement.

What do we have to play with?

I dunno if I already said it, but does anyone have acess to dyno charts for the various engines?

shogun · Post by **shogun** » Sun Sep 11, 2005 6:05 pm

well lets see if i can help, for the C engines heads there is a lot you can do to them, you can weld the combustion chambers for more compresion, yo can visit paradise racing where they sel valvetrain suitable for 8k rpms, that would be an engine close to 100hp to the wheels i think with 10.5:1 compresion ratio and oviusly a webber carb, the head can also be ported, exhaust ports just need to be polished, for low rpm horsepower and torque you should try finding a supercharger from a 4agze engine they are good for 10 psi and have 6 psi stock you can have heaps of power at very low rpms, and you could still be carburated