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1996 Geo Prizm 7Afe Turbo Build

Thaddaeus G November 29, 2010 in Pre-1997 Toyota Corolla and Geo Prizm

I am going full race/ extreme street looking for 400-450hp out of a fully forged and cryo blocked 7AFE and 7afe head with forged 4age intake and exhaust valves, 3 way head job masterpower turbo, tial wastegate, synapse bov, air to air intercooler.

I need some links to corolla suspension that will be good for autocross.

I am buying the shell Thursday which is fully stripped with 1400 dollar custom rollcage and a older 7afe engine for the rebuild with a 5 spd tranny for 350 body is rust free.

I am also wondering how hard it would be to take a blacktop 4age 6spd and mate it to my 7afe.

I am going to cryo the gears in it too.

The 4AGE has a similar bolt pattern as the 7AFE engine, so I don't see any issues with throwing that transaxle in there. If anything, I'd recommend running the E-series transaxles - they have a reputation of holding up to more power than the standard fair C50/C52 5-speeds and C160 6-speeds. If you decide on the 6-speed from the 4AGE, I'd get the one with the 12C ID code, as those have LSD equipped.

I wouldn't put too much faith into cryo treatments. Those are only worthwhile if there are known stresses in the materials being treated. Most of the parts that you will be looking at this point will be quite homogeneous, so stress relief - the biggest benefit of cryo treating, doesn't help. Some point at greatly increased surface hardness - but has been proven that surface hardness has not changed or in the best cases, improved by 1 Rockwell hardness - which is within measurement tolerance. But if they are going to do it anyways as a package deal - it won't hurt either.

There is a good section for suspension upgrades on TRD Forums for the 7th generation Corolla, be easier to send you there than just cut and paste here, plus there are other great information for boosting a 7th gen Corolla -

In any case, post up some pics when you get the parts. A shell + roll cage + rebuildable core drivetrain for $350 is pretty cheap.

Also curious why you are sticking with the 7AFE to build that much power. You could go the 3SGTE route and spend less on building up the engine to get the same power goals. 400-450HP is also a lot of power for autocross in most areas. Unless you plan on dragging the car and/or longer tracked road races (tracks like VIR or similar).

I have started to decide tonight that instead of 7AFE I will be getting a 4age head and doing a 16v 7AGE swap with the HKS adjustable cam gears and Porche timing belt. I have looked around enough to realize that the 4AGE head is the sex and I don't wanna go with the 20v as it's harder especially to tune the ecu for the ITBs with a turbo. There are alot more performance parts for the 4AGE head and as for the 400-450 HP goal that would be with like maxed out boost I want either fully adjustable boost or a boost controller that levels up as per gear.

That "Frankenmotor" 7AGE should be a good choice. G-heads are well known to flow well and takes to modifications nicely. Doesn't mean that F-heads are poor - in some cases (ie, boost) they can put up a decent fight with G-heads. But for your power goals, better to start with a better flowing head and build from there. There are a few out there running a boosted 7AGE (7AGTE) in the 330-440 power range on 18-28PSI of boost - so your goals are wholly attainable.

thanks for the link i have found a whole guide on the suspension there and will add it to the list. do you know of any good methods of eliminating wheel hop and/or wheel spin? i know a 400+ hp fwd car will spin alot and i am looking to somewhat eliminate this as power doesn't matter much if you can't efficiently put it to the ground. (nobody wants to sit n spin lol)

ive heard of the alltrac but i don't want to convert my car to awd just to get traction plus i heard thats an automatic anyways which i refuse to drive. and what are the widest tires that you can run? the guy im buying the shell from said he ran 205's no prob but for 400+ hp can these be wide enough?

also, is it better to use big port or small port for a boosted engine. i would assume big port, but i will have a harder time finding a big port as i live in the usa and i can get a 4age 89 mr2 head for 100-175 bucks.

Should be able to find a bigport one - as most of the 4AGE 16v are the big port variant. The small ports were more common on the newer 4AGE, like the ones used in the AE92 Corollas. Smallports actually make good power up to 200HP and better for N/A setups, but beyond that and for boost - better to go to the bigport. But I agree - trying to source this locally, you'll probably find more small port 4AGE heads.

That doesn't mean that the smallport is poor in comparison - just easier to get there with the bigport. Just means more tuning on your part to hit those power levels.

As for eliminating wheel hop or atleast reducing it greatly is part engineering and part art. Biggest issue is limiting the motion of the wheel in relation to the chassis (toe changes) and understanding the dynamic processes that cause the toe to change. Being FWD doesn't help matters either. Springs, struts, sways do nothing to control wheel hop. Torque mount inserts (motor mount inserts), unequal length and/or heavy duty driveshafts, beefy steering knuckles, urethane mounting bushings instead of rubber, rod ends or spherical bearings at key suspension points - can all help in reducing the chance for wheel hop. Tire choice as well - the sticker the tire, the worse wheel hop can be.

As for tire - 205 will go up pretty fast with even half that much power. If you got a drag radial - it might be able to hold up. But you are likely looking at "tubbing" out the front end to get max traction. That will make the car pretty much useless in an autocross event. Another option is to dial back boost at lower RPMs, so that you are not burning up power spinning those wheels. Here FWD helps a little, since more weight is placed on the drive wheels. But weight transfer is not optimal in a FF setup - so it is a give/take sort of thing.

Width can be as wide as you want. Since you have basically a rolling shell, you can stuff a big of a tire as you want. Widebody is the easiest way - tire just sticks out further. If you are looking for a sleeper look, then you'll have to move the suspension points inwards to make more room for a larger tire. That said, there are a couple of 7th gen Corollas running a 225 tire on mildly lowered setup without major clearance issues. If you ran a spacer - like a 10mm one, might be able to stuff in a 235, maybe a 245 tire. Still, a DOT legal drag tire, would offer quite a bit of grip. As long as you don't sidestep the clutch on launching, should be able to put some power down.

AWD is an interesting idea - 100-112HP per tire. Be one hell of a swap - not sure if the investment to make it work will be worthwhile in the end. The weakpoint there will be with the center differential and matching transaxle. The Celica ST165 and ST185 were available with 5-speeds, so you do have standard shift options. Corolla SR5 All-Trac sedan/wagons were also available with a 5-speed.


A suspension prepared for autocross or track use should not have any wheel hop problems. Even for straight line acceleration, like drag racing, you will not want a soft suspension that transfers weight to the rear in a FWD car. If you want it to turn well, you're already looking at a stiff suspension with shocks that can handle high spring rates.

Oh, and definitely run a limited slip diff if you want to have any acceleration in turns. For that much power, you're probably better off with a clutch type than a torsen diff.

Are you building it for SCCA SMF class?

honestly im new to autocross so i don't know what class i'd be in yet. i know if i build a turbo 7age i might be up against cars that are way beyond me. eventually i want to race with other people on larger tracks but autocross i am going to use as kind of a catalyst to get my skill level up for that. i'm a decent street driver but comparing street racing to track racing is like comparing street fighting to boxing. i know this as my buddy was a real bad ###### in high school and kicked everyones ###### in fights, then he went to box in heavyweight and got his ###### whooped. lol.

what i would love to see is something like this:

7age fully built with masterpower turbo

intercooler of course

megasquirt II

ford edis (hopefully 2 coils per cyl)

6 spd t60

performance suspension

performance clutch

i am going back to look at the shell again tonight and will be posting pictures of the shell so everyone can see the rollcage.

i'm picking it up thursday.

oh and why masterpower turbo?

my buddy had a ep3 turbo k20 civic si hatch that he totalled by hitting a huge deer at 75mph head on yet he was able to salvage the turbo kit.

he also has a tial wastgate, synapse bov, and air to air intercooler that i want to acquire.


Here's my $0.02 on building a custom sports car: If you think you will be using it for track days, autocross, time trials, or similar events and will want to be competitive over time-- read over the rules of talk to someone in the group as early on as possible. Knowing what you will do with the car beforehand can save a lot of money, rework, money, undoing/redoing upgrades, money, or having a severely outclassed car. Did I mention money? I always feel bad when we have a new person show up with a basically stock car, and have to compete in an extreme category (about where your finished car would wind up) because they have either an aftermarket blow-off valve or a different hood.default_ohmy

On the flipside; if you want to build a general kicka## car that is fun to drive-- build it how you want it! Even if it isn't competitive in a specific class, it will still be fun to take to the track, autocross, etc. One driver in our local AutoX group is having a blast driving a slightly modified VW Bug in a class better suited for highly modified 400-600HP sportscars.

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This is the shell I'll be picking up Thursday night.

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And this my friends, is what happens when you turbo a stock 7afe and shoot nitrous into it.

Notice the hole under the oil filter. Thats where the rod shot out.

Car looks pretty decent, a good place to start a project car. Roll cage looks very nice as well - hard to tell from the pics, but looks like it is welded to the floor. Just double check that the weld is backed up by a piece of metal or bar welded to a fairly large bracket and then welded to the floor. Cage looks plenty strong, just curious that the mounting points are equally beefed up to take the additional loading (bar will not blow through the floor on impact).

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like this?

Yup, that made it a clearer. Looks like there should be plenty of meat on that pad.

Interesting that the cage doesn't extend from the main hoop, following the roof-line, down and following the A-pillars. Just goes straight from the main hoop to angle down straight to the floor by the leading edge of the door. More of a sprint car roll cage design, where there isn't much in the front of the car. The way the top bars run by the rear window, is the way I'd expect it to run to the front of the car. Looks like the roll cage is designed backwards from typical convention.

Probably will still work - depends on the events you plan on participating right now. As the design will work plenty well for stiffening the car, more than a protection thing, which most roll cages for the type of driving you want to do are designed for anyways.

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