4a Turbo Conversions: Start With 4age Or 4agze?

[e70van]

Hi everyone, I'm looking to save my KE70 van from daily duties and give her the attention she deserves. :? (in no particular order: power, paint job, front coil-overs and a clean interior )

 

The van has a standard bigport 7rib running (standard ecu) in it atm but I'm looking to go turbo.

 

I want around 120-140kw atw max for it. i want this power and no more because i have a t50 and a t series celica diff. not wanting to go W box, r31 diff etc etc.. plus i don't think I'm that greedy :( she will move along not bad with this power :D

 

Now the main thing running around in my head is: do i work on my bigport and setup a turbo with this or buy an old GZE and use that as my base??

 

I have to work to a budget (we drive corollas, don't we all?) but at the same time i want to do it right the first time. is $3500 around the money?

 

financially speaking, a few notes to make:

driveline:

my bigport motor has a new 200mm exedy h/d clutch. would be nice to reuse this and not buy a 212mm like GZE's need.?

 

engines: stick with the beast i know, rebuild the bigport add GZE toyota pistons and GZE h/gasket OR buy a GZE, hope its in good condition and fit it..? (don't like this idea much.)

 

either way i will still have to setup oil drains, lines etc.

 

*I've just realized i've got alot of questions about this.

 

*which turbo to use? t25/t25g I'm thinking, will get that power and they are cheap to buy.

*which exhaust manifold and where do i get one?

* ignition system: on a N/A 4ag does this need to be changed to cas,coil packs because the 4age distributor doesnt adv/ret with boost?

* i do like factory toyota ecu's, and would have no problem running a GZE ecu if it can make the 120-130ish with lowish boost levels. (I'm hoping i can run 10 maybe 12psi tops to get that power. i'll be honest, i haven't researched this part much)

* does a GZE have a knock sensor?

 

 

I guess that's a start to my questions. any help, links appreciated.

 

click, post thread!

 

Andreas

Edited August 21, 2010 by e70van

[MRMOPARMAN]

if your only after 140kw, a gze will do everything you need, if in good nick. however you have to ask yourself, honestly, if you will be chasing more power in 6months time. a good 4a rebuild will end up a similar price to a gze front cut imho.

 

however, since you already have a smallport bottom end ( double check to conform though) it would end up rebuilding what you have slightly cheaper than buying a gze. only disadvantage is you don't get the cas. not a problem till over 200rwkw done right. ae101 gze pistons are cheap and a renound to handle 250rwkw +

 

a t25g would be the go, as far as 2nd hand turbos go. 140wkw would be right in its efficiency range, and have room for a bit more (170wkw approx)

 

a gze computer would work, but be a comprimise. a comprimise you may have to make if you want the car engineerable.

[TheNOBBLER[RL]]

Yeah, I'm with Cam on keeping the existing engine. You already have it and pistons etc don't cost the earth.

 

I think late bigports were 7 rib (as you have said yours is) so that should be a perfect start for a turbo project anyway. Your goal is quite achievable and should last a long time as it won't be to stressed

 

 

JP

[e70van]

Thanks for your imput fellas. :(

 

I was thinking 2nd hand GZE, but they aren't getting any newer and you really don't know what your getting.

 

As much as i like toyota ecus they are not ideal if your chasing every last kw, but look at all the r&d they have put in them compared to someone else tuning your aftermarket microtech for example. the toyota ecu will start, idle, drive everytime, any weather conditions. the wolf3d i had on my old 3sgte gave me the sh*ts.

 

the motor is definitely a seven rib. (red writing on valve covers too) but with the smallports i noticed they have an oil drain pipe on the back of the head.. do they also have knock sensors? these are handy to have are they not? retards timing when motor is warm, under too much load?

 

MRMOPARMAN In regards to the ignition system are you saying i can run my distributor/single coil setup for boost as long as I'm not pushing the motor to 200kws?

 

If i end up chasing more power i will be removing the 4a and looking into a 3sgte or 3rz, w box, another diff upgrade, brakes etc etc.

Edited August 22, 2010 by e70van

[MRMOPARMAN]

i don't think it will be a power figure where the ignition can't keep up, it will be a boost level / rpm where it missfires/crossfire will reveal its ugly head. but theres are millions of motors out there running single coil distributors and making 50kw per cylinder or more.

 

you may have to upgrade coil, leads plugs, ignitor etc. depends which ecu you go for also.

 

knock sensors are handy. not all 4a's have them. I'm not sure which do or don't. however if you go aftermarket ecu, have a decent tuner and give them the time to map the engine properly, i knock sensor should be fairly redundant. remember a motor is only as good as its tuner.

 

but like jarrad says, 140rwkw is quite a conservative power output from a 4a. if you build it right the first time, more power is just some bolt ons and a tune away. no need to swap to another engine unless you don't like peaky motors, or are chasing a tractable 220+rwkw. that sort of power in a dirty xe7x chassis will be more than you'll ever need!

[ke70dave]

  e70van said:

As much as i like toyota ecus they are not ideal if your chasing every last kw, but look at all the r&d they have put in them compared to someone else tuning your aftermarket microtech for example. the toyota ecu will start, idle, drive everytime, any weather conditions. the wolf3d i had on my old 3sgte gave me the sh*ts.

 

well it all depends how much effort you put into the tuning, if you tune all the enrichment maps (air temp, water temp, cold start) then it will drive fine in all conditions. problem is with alot of aftermarket ecu's they just get tuned for power, not driveability.

 

i vote rebuild your 4age with the gze pistons, then you get nice new rings and bearings.

[e70van]

From what ive read the last few days i think I'm going to stick with my 4age and turbo that.

Is it impossible to get an engineers cert with an aftermarket ecu in victoria?

 

few questions on the ignition setup, what do i need if I'm running an aftermarket computer like a microtech? gze CAS or can i mod my current dizzy?

 

Are the ebay highmount exhaust manifolds any good or should i splash out on a kelway manifold? will a t25g work on a highmount manifold without too much modifying on the wastegate etc?

[e70van]

damn, i thought there would be more people on here able to answer these questions..

 

Are there any good write-ups on 4age turbo conversion floating around the net that someone could kindly direct me to? :)

[MRMOPARMAN]

its not impossible to get an aftermarket ecu engineered. however it all comes down to 3 things. ecu choice, tune and engineer you end up using. work out which engineer your gonna use, and go through the build with them. its the only way to be sure!

 

on the ignition front. you should be able to use either gze cas or your original dissy, depending on type of ecu. better off asking your tuner what ecu they prefer to tune, then ask them if it will run your original dissy. some ecu's don't like mitsubishi ignition systems eithout mods, but toyotas are *usually* ok.

 

ebay manifolds people have had varying success with. some people reckon their good, some people reckon they crack. the turbo will go on, but expect it to need mods. any mods needed should be relitively easy to fix though.

 

if you want more info, go and register with www.toymods.org.au pretty much everything toyota has been done cand covered many times there. also alot more knoledgable people there than i.

[e70van]

cheers moparman :) ill ask the questions on toymods :)

Edited August 25, 2010 by e70van

[BLUDGER]

if your chasing a good aftermarket ecu go an ems, cheap and easy to use. mate had no probs gettin his done up here in qld and we program it ourselves on his laptop while driving it round.

[ke70dave]

also check out the new haltech sprint range, can get something decent for under $1000.

 

being a turbo engine you have more choice of ecus as they will easily run on a map tune (manifold pressure vs revs)

 

with an N/A you are a little bit restricted as its best to get an ecu that can run both map and tps. to get the driveability in the low tps readings.

 

the dizzy mods it will depend on what your ecu accepts as a signal, from what i understand easiest way is to use a GZE cas, or i belive that a small port 4age dizzy is similiar to the gze cas, where as the bigport dizzy is a little bit more basic, though it can be used if modified correctly. (once again pending the ecu accepted signal)

 

so you will need to pick an ecu, and then find out what signal it requires, then figure out how to mod the dizzy.

[e70van]

thanks bludger and dave :blinks:

 

i will look into ems/haltech, atm ive been looking at microtechs (everyone seems to have a microtech! bah!)

 

Dave, i found a thread on toymods about modding dizzys which is pretty interesting but i noticed if i ran a dizzy setup it would leave me stuff all room for a high mount turbo/intake piping.