4age swap questions

[20vtercel]

I'm actually a bit confused by the sudden obsession over the need for frame rigidification. I watch quite a bit of shows on TV about people SERIOUSLY upgrading their HP and they never have to boost their frames. I mean if this is just a "do it because you feel like it" thing then I'm fine with that, but I don't really understand why people are trying to justify it. Bent frames come from collisions or REALLY REALLY powerful engines like a 500HP big block. Not an un-turboed 4cylinder swap out.

I hope this isn't offensive to anyone. I'm not trying to offend anyone, but I don't actually understand why a few people are so interested in this.

The answer to your question is simple.....


What is the difference between what you see on t.v. and real life??? (and this goes for everything) You sometimes never know the whole story!!

Actually, you'd be suprised to know that most cars that get built on tv are re-worked to incorporate frame strengthening.

Also, what you see on tv is older cars with "<span style='color:red'>F U L L F R A M E S</span>" not unit bodies where there is a 1/4 frame in the front and 1/4 frame in the back. Not to mention a car in the 60's was made with HP in mind and cars nowadays have light and economical and $$$ making built into them.

Simply put...and any car guy should know this...you cannot put more than stock hp into unit body frames and expect that nothing is going to happen.

Take my camaro for example...It is a unit body. Stock, they have a problem with stress cracks starting right behind the b pillar at the roof. Guess what?? 190hp into a unit body is not a good thing. Same goes for mustangs and other cars. It is something that cannot be ignored and if you chance it...it's your problem!!!!

Oh, and i mean no offence...but there are some shows for good information and overhaulin', two guys garage (shadetree mechanic), or HotRod TV etc...are not by any means that!!! They are just about bolt-ons and slapping stuff together. It gives the viewer the basics but doesn't really go into the support for what they've done. One of the biggest laughes i get out of thoes shows is the pronunciation of the products. You can tell those guys are just hosts and not much more than that!!!

I like the overhaulin' show...they do the baer break upgrade, but what they don't tell you is that they had to upgrade the break bootser to power them!!! and so on and so forth.

IOW, you can't believe everything you see on TV!!!

Oh and another thing. 1,000,000 hp in our cars will not hurt anything...90ft lbs of torque will!!!

Remember - Torque is the power of the engine to get a mass to move. HP is the speed of which it reaches your peak power!!!

What did you use as an air cleaner and filter box?

I put a k&n cone on the end of the afm and stuck it in the fender. FWI!!!

I have no use for crap equiment like filter boxes. pffft

What happened to my frame?? Why?

It twisted cuz of the torque. Why? our frames are weak.

Trust me...you have 80hp 79ft lbs of torque. You more than double your hp and double the torque. Say the braces were only designed for the lower hp. You now need braces that are 4 times the strength of originals to handle double the torque.

[20vtercel]

i have heard of this foam type stuff you can spray that will make the frame more rigid,  will that work?

Yes there is structural foam that can be sprayed into the frame of your vehicle to strengthen it. It still does not combat the frame twisting problem. THe foam was basically designed for transverse mounted, FWD cars. It acts as a flex strengthener not a torsion or lateral strengthener

[Jonsblckhwk]

thanks for the further explanation

i guess ill have to get some temporary cheaper stuff or have a bit more downtime

thanks for the help.
so will a tubular frame be cheaper than like 1000?
and should i got to a machine shop to have it built or where else would you go?

[20vtercel]

I hope i didn't offend anyone. Seems like there is no one else replying to this thread. I re-read my information and it seems like I may have come across as being a little curt. This was not my intention!!

[russkiypenguin1]

not really.

basically it goes like this. for some reason(and you've outlined them) you think that our frames won't accept what I consider to be minor engine upgrades. I understand that to some a 80% increase in HP sounds significant but to me that's not a big deal.


I know guys who increase their HP in similar ranges on other vehicles and they NEVER think of increasing their frame strength. And they drive them for years with no problems. And I must say that they never have had any problems over the past 15 years. For that matter I know corvette buddies that step up from 330 HP(and enormous amounts of torque) to 550 HP and would NEVER consider frame reinforcement for it. These are guys that drive their cars every day.

I don't know why I'm trying to detail all the reasons why your response pissed me off.

Here's the bottom line. Your response pissed me off. I'm from Missouri. Show me. Show me a twisted frame from an upgraded engine on a Tercel Wagon and I'll believe you. Until then you'll just piss me off.

[Jonsblckhwk]

he he dont you/didnt you have 4wd rwd?

because i only plan on fwd which doesnt have as much of a torsion issue
yay one less expense

now ill only have to await more unexpected expenses

[3A-C Power]

If you have an 86, unfortunately the AE101 tranny won't fit because it's a transverse mounted one. You're stuck with the Z53 FWD tranny, and the front diff that goes with it, and that will be your weakest link in the car (assuming the frame doesn't break)

The front wheel drive Tercels before 87 different than any other FWD or RWD in the way the engine torque is supported by the frame. Because it's front wheel drive, the opposing torque comes through the drive axles which run sideways, so the engine/tranny assembly rotates front to back. That torque has to be opposed by an equal amount of torque by forces at the motor and tranny mounts which are basically two positions when looking at the car sideways. The force is proportionately less as the motor mounts get further apart. The Tercel has the tranny mount all the way at the end of the tranny, so the force at the motor mounts and the tranny mount is alot less than it would be in a conventional transverse FWD layout, where the mounts are all under the hood. When you put it in 4WD, half the torque goes through the driveshaft and twists the frame between the motor mounts and the rear axle. Something to consider for those who wish their tercel was RWD when it isn't in 4WD. (I still want it that way, so we'll see how my frame holds up)

The point 20V was making is that most of the modified cars are body on frame construction rather than unibody, so they have a heavy rail frame that goes the full length of the car. Unibodies are all stamped out of sheet metal. That doesn't inherently make them weak as they use many stampings of different thicknesses of steel which are cleverly designed to add the most strength in the right place with only as much metal as is needed. The end result is cars with a better strength-weight ratio but weaker frames overall, because they don't put in any more strength than they have to.

The Tercel has very nice box sections on the front end, and thinner ones on the back, but in between there's nothing but the floor.

A car like the AE86 Corolla was probably made stronger because they planned to use the 4A-GE in it. Is there an example of one that came with a more powerful engine later on in it's production but with the same frame? Perhaps the AE82 Corolla (84-87 front wheel drive). There were FX-16 GT-S's, Chevy Novas and regular Corollas elsewhere in the world that had the 4A-GE. They could have upgraded the engine and just did some calculations to see if the frame was good enough, or they could have designed the frame with allowances for future engine upgrades. Unfortunately the Tercel only ever came with the 3A engine with 86 hp at most.

I think you could get away with using more power as long as you are reasonable to the car. I don't mean you can't step on it, I mean you have to be smooth in doing so. My reasoning is that the 3A-C can spin the front wheels on dry pavement, and in doing so it exceeds the maximum torque that can be placed on the Tercel drivetrain. When you twist a frame due to engine torque, there are two forces involved - the engine and the wheels. The wheels just have to give back what the engine puts out (x the gear ratio x the diff ratio). If you jack the car up, you could pop the clutch at the redline and not do damage. If you hold the brakes down and do the same thing, there will be damage. The torque the wheels are able to get in driving conditions is limited by the peak adhesion value of the tire - which is around 0.8 (0.8 times the weight on that tire, so the maximum torque is that times the radius of the wheel) Once that torque is exceeded, the wheel starts spinning and the frictional force and resulting torque at the wheel goes way down.

You can put that kind of torque into the Tercel's frame with the stock engine, but only for a couple seconds. You are using the inertia of the engine to put out a torque that is way higher than the 70 ft-lb the engine is rated for. Because people can and will do that, driveline components are designed to safely handle 3-5 times the maximum torque of the engine. The principle of impulse and momentum is at work here. Momentum is mass times velocity, in the case of the flywheel turning it's rotational speed times moment of intertia (mass in a rotational sense) of the flywheel. Impulse is force times time that force is applied. The impulse is equal to the change in momentum. When you have that flywheel spinning at 6000 rpm, pop out the clutch and it goes down to 3000 rpm in half a second, there's an impulse in the drivetrain of a certain force over that half a second. In reality the force is much greater at first and we would use derivatives and integrals to find out the force as a function of time, but multiplying and dividing gives the basic idea for simplified situations. To get the force, take the impulse and divided it by the time. If the time is zero, the force is infinity. If the time is really close to zero but not quite, the force is some very large number. In this situation, the spring in your clutch pressure plate is more critical than the torque of the engine - if it's hard enough to lock the clutch to the flywheel twice as fast, you end up with alot more torque. It's only for a fraction of a second before the wheels get spinning and the engine slows down, but metal doesn't need alot of time to break. Maybe we should use the 3A-C clutch and flywheel to be on the safe side?

The 4A-GE puts out twice as much torque when you have it to the floor with the clutch out, but you can get the same torque with the 3A-C by revving it and letting out the clutch quick - you probably do it all the time because you have to in order to get it moving. In real world driving situations, the extra torque of the 4A-GE would help a great deal even if you never exceed the same torque you put out every time you start off in first gear with the 3A-C. Trying to accelerate to pass on a 2-lane road for example, with the 3A-C you could go from 3000 to 6000 rpm in 3rd and put out close to the same torque all the way through and get up to 100km/h, but with a 4A-GE you could go from 3000 to 8000 and be doing 130 before you have to shift, with torque increasing the whole time. For a while, you would be putting 2x as much torque out, but again this is nothing compared to when you start off.

Acceleration force (what pushes you back in the seat) increases directly with the torque at the wheels, so a good indicator of how much torque is in your drivetrain and your frame is how much you're being pushed back. Or how far your inclinometer goes back during acceleration. Try flooring it in extra low on dry pavement and popping the clutch out, while crouching forwards in the seat. You'll be slammed back really hard. Is the frame okay? Can you imagine getting anywhere near this much force from flooring it in 3rd gear on the road? Imagine accelrating twice as hard as you can right now through any gear, and it's still not anywhere near as hard as that clutch drop.

Now where you will get into trouble is if you do clutch drops from 8000 rpm instead of 6000 with more static torque on top of the inertial torque and a clutch that grabs harder. Not to mention if you use 4WD all the time, doubling the peak adhesion. That brings me around to the fact that remains that the only one of us who as actually used a 4A-GE in a Tercel, has twisted the frame. He did the conversion for fun, and no doubt had lots of fun with all that power (plus a turbo) and should the desire remain, could have reinforced the chassis and been back in business. But why bother when there are much faster cars to be built?

I'm used to 62 horsepower, it's all I've ever had, and I still don't drive that hard even to get what I can out of the 3A-C. I've driven the Tercel 4WD since I was 16 (I'm 23 now) and at this point of my life I could afford something about 10x as fast (not that that would be wise, but if I really wanted to, I could). The fact that I've remained with the Tercel goes to show that power is only part of the equation for me. I have other reasons for going to the 4A-GE 20 valve completely aside from power - the technical feat of doing so and the appreciation of the engineering that went into that engine. They are also very smooth and efficient in stock form. It's not practical by any means. I'll probably screw the tranny, front diff, rear diff and maybe the frame, before I either conquer those weakness through design or decide it's not worth it and revert to a 4A-C or 7A-C with a Weber, stronger cam, head work and 2" exhaust which would be practical, safe and give me all the power I need. Or I could be okay because I'll be careful with all that power, understanding what is safe for the car that it's in and what would cause damage.

20V Tercel, thanks for all you contribute to this board and giving us encouragement to go ahead with our projects knowing it can be done.

[Jonsblckhwk]

so is the z53 fwd tranny the stock tranny?
would it be cheaper to beef up the stock tranny or make a different tranny fit?
and what am i looking at ballpark to get the tranny to hold 250 whp

[Thereminator]

I agree 3-A,20vTercel has supplied great amounts of info. from the "other side"! I hope others appreciate your skillfull explanation of all the value's(torque ect...)in question. I myself,in keeping with my typically selfish nature,hope that you opt for the modified 4-AC...Webber...Header's...Performance Cam...Ever-so-slightly Milled Head...Let the drooling :blink: begin!!!

[Jonsblckhwk]

god knows i appreciate any help i can get from anyone
but there are VERY few people who i can ask multiple questions to and recieve frequent and accurate answers
and for that 20vtercel i really do appreciate it.

and without your help i would pretty much be SOL on my project car.

i dont know what i would have to do if it wasnt for people like 20v tercel and JDLangevin (technician doing the swap) and a few other people.

[3A-C Power]

The Z53 is the 5-speed, front wheel drive tranny. Same case as the 4WD version (Z54F for 85-88, Z52F for 83-84) same bellhousing and front differential case, but shafts are different and what goes on the back is different. 2WD trannies have an extension housing where the shift linkage goes in, 4WD has the transfer an then the extension housing where the shifter goes directly in, and the rear driveshaft goes in. Upgrading the Z53 is about as hard as upgrading the Z54F, which 20V Tercel has done with a little help from his friends at the tranny shop. If you go to some random shop, it will cost a ton. Shit, I don't know what to say, 250 horsepower at the wheels is a lot for that tranny to take. I'm going to design my own tranny parts, but that will take a while and they will be different because I have a 4WD. Making any other tranny fit will be harder at any rate, first you have to find one with the same basic configuration as the Tercel's (longitudinal engine, front wheel drive) which I could name about two - the Chrysler Intrepid (those trannies mostly end up on the highway after they blow apart) and the few Subarus that aren't AWD. Maybe you could look for jobs at some tranny shops sweeping the floor and maybe pulling trannies and other stuff, otherwise it will cost alot.

[20vtercel]

Your response pissed me off.

I'm sorry you feel that way. I was trying to explain that there is more to it than just bolting in/on parts.

I wish it were that easy. I personally have seen my fair share of twisted frames and bent cradles. I'm not saying that it IS going to happen. It happened to me and I'm conveying concern that it might happen to some of you. I'm just suggesting to be careful. My bud has a frame straitener and I might just try to straighten the frame.

I'll get you your pic. You'll have to wait till the snow goes but you'll get it!!!

Thanks for all you that have used the info I have given and understand where I'm comming from. I'm not always right, but I know what has happened by personal experience...


One more example of how frames can't take torque (unit bodies). My brother's friend had a 1981.5 turbo 280Z. The head cracked and they replaced it with a 350 (direct bolt-in with few extra holes). He took the car out, no cage, punched it. never drove strait again untill he put the cage in! It had a sunroof and it buckled there. It was an easier fix than some.

I would like to add to a comment made by 3A-C Power, the part about dropping the clutch. Well, if you have pizza cutters, the spinning of the tires is the effect of delivering more power than the wheels can hold.

Say, stock 155's can hold 65ft lbs (10 ft#'s less than stock) before they spin in FWD. I put 205 avid's on my car. a performance tire. if they hold 100ft-lbs before spinning, and I'm spinning them with ease, then there is 35ft-lbs that is being delivered to either the tranny or frame. Frame is designed for 85ft-lbs (10ft-lbs more than factory power) and the tranny is built for the power of the engine...where does that extra power go to??? The engine mounts. The rotational force exirpts a down force of 17.5 ft-lbs (about 25lbs) at the passenger side engine mount, and the same upwards force on the driver's mount. So that's about 50lbs extra weight instantaniously on parts of the car that aren't supposed to see that torque. Now, 4WD you put 125ft-lbs under the hood (a stroked 4ag/7ag can have this) and with thoes same tires, you can hold 200ft-lbs. All the force is now going into the frame. your car wrenches clockwise in a fraction of a second with over 130lbs extra force on already stressed points of the car. Something is going to happen!!

just my $0.02

[Gasoline Fumes]

Remember rust will weaken a car's body too. My rusty 1984 Civic's body started to develop a few cracks with basically stock power. Just something to think about with 20 year old cars.

[Jonsblckhwk]

I just got a U2U from the guy doing my swap JDLangevin and he said:
"If it's front wheel drive, then the engine and transmission are transversly mounted, so I don't know what that guy is talking about":huh:

i cant say anything until i have the damn car.
but i guess its okay that i dont have it yet because i will have rims and tires and front struts/springs wating for it

also are there any differnces in the space for an intercooler between the 2wd and 4wd models?
if not what intercooler should i be looking for the the 2wd 86 tercel?

would a supercharged car need a different intercooler than a turbocharged car?
becuase i might ditch the supercharger for a turbocharger but i dont wnat ot have to purchase all new plumbing and whatnot?


he he forgot to mention what you already knew it is a FMI because its kind of hard to make a scoop look stock :ph34r:

not that an intercooler is as gaudy but you shouldnt see it unless you are looking

[3A-C Power]

If your 86 doesn't have air conditioning or you plan to remove it, the intercooler can go in the place that the a/c condenser fits. That would make it easy to mount and you wouldn't have to cut anything.