4AGE 100kw smallport turbo rebuild

[BoostBoy]

To clarify, the GZE forged pistons can be purchased new at toyota. I have read that these will take up to 20psi max (don't quote me though). I'd say 15psi reliably. You will not need to hone your cylinders, as the GZE pistons are a direct replacement for the standard ones. You'd be suprised at how little difference there is between the supercharged block and the naturally-aspirated block.

A good example is Australia's fastest MR2 (i think it still is), using an internally standard gze, running 25psi to get 204kw @ wheels! I'm aiming for that sort of power, but not initially...mine should be a bit stronger than a gze block...it will be interesting to see if I can duplicate these results.

Does oversize mean that the pistons are actually larger and I will have to hone the block to fit them....can you just get them in the normal bore size...what's the difference?

Disregard this, I know a bit about this now...I will probably have to hone the block a little to fit some oversize gze pistons, because my standard block will be slightly worn out and not fit the standard piston size.

[roadsailing]

you have to OVERBORE a block to fit oversize pistons

HONING basically referres to giving the bores a specific "roguh" finish so your rings will bed in properly.

when rebuilding an engine, it is a good idea to overbore and hone the cylinders to fit oversized pistons, then it's like new.

then you need to run it in properly!

[feral4mr2]

A good example is Australia's fastest MR2 (i think it still is), using an internally standard gze, running 25psi to get 204kw @ wheels! I'm aiming for that sort of power, but not initially...mine should be a bit stronger than a gze block...it will be interesting to see if I can duplicate these results.

he changed his internals ages ago before he did his fastest run. running arias now if i remember correctly.

fatmr2 got ~200rwkw with a stock 4agze useing gze pistons.

[4agte]

he is making more than 204 atw from what ive read in zoom but they were using touleen and n/a cams im guessing it was blue top cams. Aparantly the 200 or so kw atw was obtained on stock internals using pump fuel.

[The Witzl]

selecting rods is more a question of RPM instead of power... this discussion has come around several times in fact, here is my favourite one - http://forums.toymods.org.au/index.p...598721f17492d1


As for the ignition system.... as i've said about 11 billion times before (and in that twincam thread too most likely), if you are going to turbo a smallport you should just fork out the 10/5ths of fuck all for a dribbletech LT10S and X4 ignition module and coil packs (~$1400-1500)..... then everything just wires up to your factory smallport shit.
BANG, fire it up when she's ready and drive it down to get tuned.

Dont waste time using a GZE computer and piggybacks and gze wasted spark systems.... just do it properly.

[DigitalPho3nix]

why aftermarket rods there is no need unless you are chasing more than 200 kw atw pleanty of times they have been proven to be reliable in big hp applications.

I wouldnt change a thing rebuild it to factory specs and wind the boost up!!!

Pleanty of people are running more than 20psi on stock gze pistons

I see it a different way. Why not get the rods done now instead of later? ie. over prepare for the impending power gains. It'll save money in the long run, and when you want to nudge the boost up a couple of psi, you can with little hassle. I reckon it just saves having to rip apart the engine again when you go for a power gain. You know what they say, once you start, you can't stop!

I think there is a huge difference in 200 'reliable' kw and 200 'unreliable' kw. Do it properly the first time around I say.

In the wise words of teh witzl, give yourself engineering headroom.

[oldcorollas]

balancing and arp bolts could never hurt i guess

just to echo...

BALANCING IS ONE OF THE BEST THINGS YOU CAN DO FOR A MOTOR

[myne]

How much is a good set of rods and at what boost/rpm level do they become an important upgrade?

[4agte]

I see it a different way. Why not get the rods done now instead of later? ie. over prepare for the impending power gains. It'll save money in the long run, and when you want to nudge the boost up a couple of psi, you can with little hassle. I reckon it just saves having to rip apart the engine again when you go for a power gain. You know what they say, once you start, you can't stop!

I think there is a huge difference in 200 'reliable' kw and 200 'unreliable' kw. Do it properly the first time around I say.

In the wise words of teh witzl, give yourself engineering headroom.

well if you allways take that point of view why not throw $100k at the motor and put in the stongest most exotic and expensive parts so that you have enough headroom incase you feel the need to wind up the boost a tad

what kind of power are you looking to make boostboy and do you intend on circuit drag racing etc?

[myne]

Yeah there comes a point where you question the point of upgrading more and more bits just to simply make sure it doesnt blow up.
Toyota already heavily over-engineered the gze, so surely a decent balance and a thorough rebuild is enough?
What's the max on a stock smallport gze bottom end with stock redline? 250-300kw?
I think thats enough for most of us.

[oldcorollas]

ahh, but if you are talking kw, then you are talking rpm...

250kw at 6000rpm is a lot more boost than at 10,000rpm...
250-300kw at stock redline is a shitload of boost, and then you may have other issues...

it would be nice if people talked about torque and the width if their powerband, but alas no.. it's all about the kw

[myne]

Heh, that actually crossed my mind.

Afterall, the force (400ft/lb @ 2000rpm =152hp)
Is actually probably lower than (133ft/lb @ 6000rpm = 152hp)

But how do you draw the line?

We all know a single pre-ignition can cause pressures many times higher than expected, so is that what we engineer to?

[BoostBoy]

fatmr2 got ~200rwkw with a stock 4agze useing gze pistons

Aparantly the 200 or so kw atw was obtained on stock internals using pump fuel.

pete-repeat....that's what I posted the first time...standard internals ~200kw @ wheels

The fact that the pistons were changed when seeking more power, gives me an indication that the standard ones were probably not much good after this.

Dont waste time using a GZE computer and piggybacks and gze wasted spark systems.... just do it properly.

Yep, I never intended to use the standard ecu and/or piggyback systems...will be most likely going microtech (or dribbletech if u like) with the X4 ignitor box...why, because it does the job no more and no less...I don't care about Motec this and that, etc, etc., and paying an arm and a leg for one.

I think there is a huge difference in 200 'reliable' kw and 200 'unreliable' kw. Do it properly the first time around I say.

That's exactly right and that is what I intend to do...BUT in reality there is always constraints...in my case (and in most peoples) it is the budget. But I would love 200 'reliable' kw and to run daily like that.

what kind of power are you looking to make boostboy and do you intend on circuit drag racing etc?

so is that what we engineer to?

I'm glad this was brought up. We engineer to what we want out of the car and the motor! I'm not going to be circuit racing (I wouldn't choose a FWD for that) and I will be doing a few runs here and there (I chose a FWD for that to be different, but also not the best choice for drag racing), I want it to be a reliable daily driver with power when I need it...but the main reason is so I can have some fun. Clearly I don't want to spend a fortune for a few runs here and there...but I do want it to be reliable and make some good power when I want it to.

Just to let you all know, I'm chasing 200kw @ wheels, possibly low 13s/high 12s quarter mile.....but eventually I want the potential to go low 12s. So with this in mind I don't want to keep stripping the motor and rebuilding with stronger parts, but on the other hand I don't want to get something that's overkill and blow the budget in the process. I'm trying to find a happy median but that's always hard to do!

I will be happy if the motor can take power in the ~160kw-200kw @ wheels range initially, but potential for ~250kw @ wheels or whatever gets me to low 12s. If this means I will need forged H beam rods, then so be it, if this means I need forged Arias pistons then so be it. Many people have built a ge motor for this power and it is only from their experience with the parts to use, etc., and reliability that I will listen to. I'm not going to base any decision on rumours or heresay, only on facts...because I want to do it once right the first time.

[4agte]

yup agree 100% if your chasing that much power it will atleast need forged pistons but im sure someone who has experince with a build like that will tell you what you need. Backyarder has a pretty seriou 20v im sure he could point you in the right direction.

im aiming for 200 rwks's atm and im planning to run the stock motor if it pops it pops and then ill rebuild it but im quitley confident it wont

[BoostBoy]

yup agree 100% if your chasing that much power it will atleast need forged pistons

Maybe you're getting your wires crossed here as well...as was stated previously the GZE pistons ARE forged and ceramic coated. It's just a matter of how much power they can take versus the aftermarket Arias pistons and the like.

That's basically what I want out of this thread:

How much is a good set of rods and at what boost/rpm level do they become an important upgrade?

answers to these type of questions. At what level of power, boost, rpm, torque, do these aftermarket goodies become an important upgrade?

For example, someone with experience and knowledge should be able to tell that 200kw @wheels in a FWD GEN3 small port 4AGE will need:

Pistons: Arias forged, new rings
Rods: standard, shotpeened, ARP rod bolts
Crank: standard
Head: standard
Turbo: GT28

etc, etc., for example. Can someone make a list like this please...otherwise we are just going around in circles.