4AGE 100kw smallport turbo rebuild

[BoostBoy]

Good to be back on the Toymods forums....I can't find any of this info anywhere else

I am considering rebuilding my standard GEN3 100kw smallport 4age to cope with a turbo setup. Initially I wanted to buy a 4agze half-cut from an AE101, but I changed my mind as I discovered the motors were essentially the same. Rebuilding the standard motor will most likely save me a heap of money as well as reassuring me the motor is rebuilt with quality parts, and also save me some engineering headaches.

My main concern between the difference of the motors is the ignition system as this seems to be the main difference (besides the fact I will have to upgrade my pistons, etc, for strength). The AE101 gze has a distributorless ignition system utilising twin coil waste spark system firing two cylinders simultaneously. If I use my 4age head, I won't have this. Will this affect the performance at all? What are the advantages of this system? Will it be possible to convert my 4age head to use this system with minimal fuss?

My other questions were concerning the strengthening of the motor and also the type of parts to use. From what I can gather I will need new pistons, bolts and rods, rings, bearings, crank and a metal head gasket. What brands should I use and what compression should I run? Also will I need to strenghten anything in the head? Is the smallport head better for a turbo than the large port head?

Sorry for all the questions, but I want to do this conversion as soon as possible and now with my new mindset of converting the standard motor, I pretty much have to start all my research over again

Any help would be greatly appreciated!!

[roadsailing]

if you are wanting a budget setup, then i would just buy a MAP sensored GZE with DLI complete, it will save you heaps of money. as soon as you start trying to put together a certain engine loom, it will take ages and cost more - i know from experience.

if you were doing a proper buildup, i'd start with the smallport, pull it down and rebuild with GZE pistons, clean up the head and reco everything, then put it back together with custom turbo manifold, inlet manifold etc and use aftermarket management.

really depends on what you want.

do much more research too!

[BoostBoy]

Hmmm, I'm getting mixed signals here. Like I posted, originally I wanted a 4agze half-cut....but what's the point if the engine i have is basically the same?? Wouldn't it make more sense and be cheaper to rebuild what I have with fresh pistons, etc., and then also have peace of mind that the engine is stronger and has not been thrashed?

I am in the process of getting a quote with a 4agze half-cut and then converted to turbo, and then dropped into my Corolla. From what I can gather, that method is very expensive and I reckon it would be better for me to spend the $$$ on rebuilding and turbo converting my original motor....make sense?

BTW, I found out about the ignition system....I'm going to use a Microtech so I can just pull out the original distributor and replace it with a crank angle sensor from a gze, then I have to get some coils and wire it all up.

[4agte]

i would just rebuild it with smallport gze pistons and rings then give everything else a tidy up. Basicially new bearings seals etc.
GZE pistons can be had for less than $400 and the rings i belive are $150 or so and they should be good for up to 200rwkws.

The standard ignition should be fine save for some upgraded leads and suitable spark plugs. You can even go the route of using the stock map sensored gze computer and wiring or as i would buy a decent aftermarket ecu even a cheap one like a microtech will do. I went mid range and bought a wolf3d ver4 plus.

You will need to upgrade the injectors and even stock gze injectors will run out of puff at about 150-160kw atw which is the kind of power a half decent turbo setup should make. There are a couple of options here 440cc items from the 7mgte which are black and should cost no more than $150 then there is the 550cc 13bt rx7 injectors but im unsure of the cost.

Next will be the fuel pump i would use a walbro intank 255lhr pump the are uber cheap and work well.

[BoostBoy]

I've heard different things about using the small port and large port head. I would like to use what I have, but if there is a significant difference when using the large port head, then I might use that. I would have thought that having large ports is a better thing for flow, but I've heard conflicting things like the small port head has better airspeed and therefore better flow.

Can anyone help me out here?

[confuzion]

yeah mixed responses re smallport vs bigport, i personally used a bigport head on my ae101 gze bottom end with arias forgies and a hksgt2510 which made 250rwhp - no complaints from me. However seeing as you have a smallport already just keep it and do what the others recommended (gze pistons etc)

[BoostBoy]

Well I'm thinking of buying Arias pistons....does anyone know the cost? From what I can gather from a few searches they're around $900...does that sound right?

I just can't make sense of having the engine open and then putting in second-hand gze pistons...I'd rather do it properly and get a proper set of forgies....but then one of the factors is the major difference in cost

[roadsailing]

toyota 4AGZE pistons ARE FORGED AND CERAMIC COATED

just use a new oversized set of them, they are only around 400 bucks for a set.

[BoostBoy]

I KNOW THEY ARE FORGED AND CERAMIC COATED...what I meant to say is get a set of new forgies. I didn't know that you could get a new set of gze pistons...If there is no difference in quality and reliability then I will get the gze ones. 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?

Another question...is there any advantage of shotpeening the standard rods and crank?

[roadsailing]

sorry if you took that the wrong way, i used the second biggest font instead of the biggest.

what i meant was, if you were going to get a new set, might as well get them new from toyota.

i'd leave the crank, but get it crack tested, shotpeening the rods is a good idea, but if you are chasing huge RPM i would get some aftermarket rods.

[BoostBoy]

Ah thanks. And I guess ARP rod bolts....what about O-ringing and balancing? What do you think a full reco with all these goodies should cost me minus labour?

[4agte]

i guess its up to you with the o-ringing thing but these days with decent aftermarket ecu's is it nessecary?

balancing and arp bolts could never hurt i guess

[NVD05X]

i cant remember if he is on this forum, but try PM'ing "MrRevhead" on the twincam forum about the GZE pistons and rings...

from what i've read on there he can get them for a VERY good price.

[DigitalPho3nix]

I KNOW THEY ARE FORGED AND CERAMIC COATED...what I meant to say is get a set of new forgies. I didn't know that you could get a new set of gze pistons...If there is no difference in quality and reliability then I will get the gze ones. 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?

Another question...is there any advantage of shotpeening the standard rods and crank?

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.

As for shot-peening, I am fairly sure that it will make a difference in your reliability stakes when going for the higher boost levels. If I were you though, I'd get the standard crank SP and balanced, and new bearings, and buy aftermarket rods; like ARP for example.

[4agte]

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