Twin Webber's...

General discussion about our beloved Tercel 4WD cars
86creamdream4x4
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My tercel:: Ex 86 tercel 4x4 automatic

Twin Webber's...

Post by 86creamdream4x4 » Fri Mar 30, 2018 10:03 pm

I'm putting together my ( build plan ) for when we grab a wagon.. Has any body put a twin Webber carbarator set up on a stock tercel with volicty stacks? If so how did you it?
Thanks bryant

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Petros
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Re: Twin Webber's...

Post by Petros » Fri Mar 30, 2018 10:41 pm

you would have to fabricate your own manifold, that would be costly. I am not aware of any one that ever put in duel webbers, the engine is not suitable or it, it is an eight valve head, and they are small valves at that. so it is limited in power.

We had one forum member that installed four Yamaha 750 (36mm) motor cycle carbs. apparently they can be purchased cheap because many like to up grade their bike to larger carbs, so there are lots of stock yamaha carbs available cheap. he cut off the factory manifold and used rubber hoses and hose clamps to adapt the carbs to the engine. he took some time messing with the jets, but those too are common and available. It really looked cool to see four little carbs in the engine bay on a Tercel4wd. he got it so the economy was similar, but with a lot better throttle responce. This seems to me to be a cheaper and better approach than to use costly duel side draft webers. I can not find the link to the old thread, but it is in the archives.

But frankly, if you are going to that much trouble you should just go to the 4age (16 valve engine) and there are dual carb manifolds available for that engine, it would be a fairly easy swap. biggest issue would be to fabricate a new exhuast header to fit in the tercel, but it is doable.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

86creamdream4x4
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Re: Twin Webber's...

Post by 86creamdream4x4 » Fri Mar 30, 2018 11:54 pm

The Yamaha carbs sounds neet! Here I was thinking of doing a complete motor swap to something that in newer and fuel injected so I can toss on a huge turbo.. Now you got the old hamster spinning in his wheel... If you find the link send it to me... I'd like to get a good look at it
Last edited by 86creamdream4x4 on Fri Mar 30, 2018 11:59 pm, edited 1 time in total.

86creamdream4x4
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Re: Twin Webber's...

Post by 86creamdream4x4 » Fri Mar 30, 2018 11:59 pm

I've been here for about a week and I love it.. I'm always meet with knowledgeable and insightful advice!! You people make me want to sell every thing I got and run .. Not walk run to grab a wagon..

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helipilot77
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Re: Twin Webber's...

Post by helipilot77 » Sat Mar 31, 2018 6:10 am

If your going with a 4A-ge it would probably be best to get the throttle bodies off of the 4A-ge 20 valve since it is bolt-on. you might have to run a stand alone ECU to make them work but it would be cool.
. / TOYOTA
./_| |/|/ |]

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Petros
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Re: Twin Webber's...

Post by Petros » Sat Mar 31, 2018 7:45 pm

I would not advise trying to turbo a 3ac, the head design is marginal and will give you nothing but head gasket trouble. It does not cool evenly and will compromise the head gasket fast to force more air/fuel mix into it with a turbo. you will need to replace the head gasket every 2-3 months (I got good at replacing head gaskets on the 3ac after I tried to tweak it for more power, than gave up on it and went to the 4ac...ultimatly I want to go 4age with efi.).

the 3ac is not suitable for more power, the 4ac is an easy swap and the water jacket in the head is redesigned and should take a lot more abuse, plus you get 100 cc more displacement. but as pointed out, going to the 4age is the ultimate up grade, double the horse power (in stock form), and improve the reliability and the fuel economy as well. though that is a much more complex swap than the 4ac, but at least all of your "hard point" bolt up will be the same. issues come from custom exhaust, hood clearance, and flywheel mods. All are solvable, but if you can not fab your own parts it will drive costs up considerably.

here is the Yamaha carb conversion thread, unfortunately the links to the picture are all broken now.

viewtopic.php?f=2&t=6690&hilit=prescott

attached is a picture I found of these carbs mounted on a 4age using the simple rubber hose and clamp adapter, it looked similar to this installation but it was on a 3ac (I recommend going to the 4ac for better reliability and a little more displacement).
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'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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LowBuckCanuck
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Re: Twin Webber's...

Post by LowBuckCanuck » Sun Apr 01, 2018 2:53 pm

Petros wrote:
Sat Mar 31, 2018 7:45 pm
I would not advise trying to turbo a 3ac, the head design is marginal and will give you nothing but head gasket trouble. It does not cool evenly and will compromise the head gasket fast to force more air/fuel mix into it with a turbo. you will need to replace the head gasket every 2-3 months (I got good at replacing head gaskets on the 3ac after I tried to tweak it for more power, than gave up on it and went to the 4ac...ultimatly I want to go 4age with efi.)
Turbo-ing a tercel always comes up, and you always advise against it it Petros, but has anyone ever tried supercharging a 3a? I've been looking at the Aisin AMR300/AMR500, small (and cheap to buy) superchargers designed primarily for 250cc-1000cc, and 1000cc-1600cc engines, respectively. Wouldn't it be possible to lower compression with a thicker headgasket, then put the boost to it? Supercharging would definitely be less of an undertaking, no oil supply/return lines needed, and no exhaust turbo manifold needed either.

All this is purely academic, I just wanted your opinion on it.

86creamdream4x4
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Re: Twin Webber's...

Post by 86creamdream4x4 » Sun Apr 01, 2018 5:10 pm

OK guys .. Let's say that I'm going with a 4ac. Do I need a flex plate to marry it to the 4x4 transmission? Or is it a direct bolt?

tercel4wdrules
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Re: Twin Webber's...

Post by tercel4wdrules » Sun Apr 01, 2018 6:16 pm

The 4A-C is direct bolt-in... Just need the water pump housing and the motor mount brackets from the old 3A.
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86creamdream4x4
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Re: Twin Webber's...

Post by 86creamdream4x4 » Sun Apr 01, 2018 8:51 pm

Sweet ..

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Petros
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Re: Twin Webber's...

Post by Petros » Sun Apr 01, 2018 11:17 pm

LowBuckCanuck wrote:
Sun Apr 01, 2018 2:53 pm

Turbo-ing a tercel always comes up, and you always advise against it it Petros, but has anyone ever tried supercharging a 3a? I've been looking at the Aisin AMR300/AMR500, small (and cheap to buy) superchargers designed primarily for 250cc-1000cc, and 1000cc-1600cc engines, respectively. Wouldn't it be possible to lower compression with a thicker headgasket, then put the boost to it? Supercharging would definitely be less of an undertaking, no oil supply/return lines needed, and no exhaust turbo manifold needed either.
it is not the compression ratio that is the issue, it is the peak pressure achieved during the combustion cycle. it erodes away the head gasket and causes it to fail. I had a high compression engine (flat top pistons plus milled head surface), about 11.25:1 compression ratio (vs. stock about 9.4:1), that raises the peak pressures during compression. when you super charge or turbo charge the engine you are effectively using the boost to also raise the peak pressures, and you will suffer the same problem. It is a waste of time to get more power out of the 3ac if you expect it to be reliable. in stock form is not a bad engine, but anything you do to get more power out of it effectively raises the peak pressures in the combustion chamber and you risk the same head gasket problems.

Realize there is no magic to produce more power, you have to increase the volume of air and fuel going through the engine, that will increase the peak pressures during the combustion process. Putting on a supercharges does not generate more power output unless it is increasing the interal pressures during combustion. going to a larger displacement engine does that without raising the pressures as much, and the 4a head is an improved design that does not have the same uneven cooling problems as the 3a head.

if you do not believe me, go ahead and give it a try. I am trying to save you the trouble I learned the hard way.

good luck.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

teranfirbt
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My tercel:: '86 SR5 4WD, 5AFE, lifted rear, 195/70/14 tires
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Re: Twin Webber's...

Post by teranfirbt » Mon Apr 02, 2018 5:58 am

While I'm all about off the wall builds and a little craziness, I think the fact of the turbo 3AC matter is that it's not practical. You'll put a ton of work into building a custom turbo manifold, all of the intake plumbing, intercooler, oil lines, coolant lines, fuel injection (you'll want a stand alone fuel system for boost!!!) and end up with ~100-115 horsepower, which is the rating for a stock blue top 4AGE.
In terms of a swap, all of the 6 bolt crank A engines should bolt straight up to the Z54 transaxle, with the possible exception of the 7AFE due to oil pan clearance. That covers the 4AC, 4AF, and 4AFE. The 4AGE requires either a modified Tercel flywheel or (possibly, I haven't confirmed) swapping in a 4AFE crank, although that only works for the early big port 4AGE.

At one point I had CBR600 throttle bodies on my 3AC (mostly for giggles) and I've now got a 4AFE swapped in.
The CBR throttles were built up by taking a factory intake manifold, cutting off the flange, then using it to build up a custom adapter manifold that use factory Honda throttle body boots. Control was done with a Megasquirt ECU running Alpha-N load sensing (which is a huge pain in the ass).
The 4AFE has a custom intake manifold and exhaust header, along with some custom bits to make the cooling system work. It's not quite the same as pictured since I added AC back in, the header is different to clear the compressor.
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LowBuckCanuck
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Re: Twin Webber's...

Post by LowBuckCanuck » Mon Apr 02, 2018 9:56 am

Petros wrote:
Sun Apr 01, 2018 11:17 pm
it is not the compression ratio that is the issue, it is the peak pressure achieved during the combustion cycle. it erodes away the head gasket and causes it to fail. I had a high compression engine (flat top pistons plus milled head surface), about 11.25:1 compression ratio (vs. stock about 9.4:1), that raises the peak pressures during compression. when you super charge or turbo charge the engine you are effectively using the boost to also raise the peak pressures, and you will suffer the same problem. It is a waste of time to get more power out of the 3ac if you expect it to be reliable. in stock form is not a bad engine, but anything you do to get more power out of it effectively raises the peak pressures in the combustion chamber and you risk the same head gasket problems.

Realize there is no magic to produce more power, you have to increase the volume of air and fuel going through the engine, that will increase the peak pressures during the combustion process. Putting on a supercharges does not generate more power output unless it is increasing the interal pressures during combustion. going to a larger displacement engine does that without raising the pressures as much, and the 4a head is an improved design that does not have the same uneven cooling problems as the 3a head.

if you do not believe me, go ahead and give it a try. I am trying to save you the trouble I learned the hard way.

good luck.
So the 4a is able to withstand these pressures?

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helipilot77
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Re: Twin Webber's...

Post by helipilot77 » Mon Apr 02, 2018 11:03 am

If you want a boosted engine go with the 4A-gze out of the MR-2 it came from the factory with a supercharger, and was made to take the punishment. I agree with Petros the 3A cylinder head cooling design is a weakness. If any perfomance mods are done it is best to swap to a 4A engine before proceeding.
. / TOYOTA
./_| |/|/ |]

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LowBuckCanuck
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Re: Twin Webber's...

Post by LowBuckCanuck » Mon Apr 02, 2018 12:32 pm

The problem is, you get to creative with engine swaps and modifications and you grenade your transmission. Now, on my dream build I'll get a custom transmission made with hardened internals.

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