Is it possible to do a 4ag (big port) head on a 7afe with the same wiringand map based ECU?
I know that it is better to change out all wiring and ECU, but it it possible to use the wiring that is already there?---the reason I want to do this is I only have my car to drive right now and I drive 20-30min. to work everyday, BUT I think that my 7A head is what is holding be back from getting more power.
Any help and/or even alternative is appreciated- I just need more power.

Also I have just bought and am about to install a b16 manifold w/7a flange,38mm tial wastegate, and a GT3076R ball-bearing turbo.

2 optionsL

stand alone ecu.....

or 4a ecu

not necessarily... you could have the 7afe ECU re-programed to work a 4ag, but the far less sophisticated answer is the stand alone\ecu swap.

the 7a does, after all, have several sensors etc that the 4ag does not. such as the like... three cam angle sensors. >>

hey fallenhero,

does the 4ag have some sensors the 7a doesn't have?

-playr158+Sep 10, 2005 - 1:20 PM

option 3

buy a block like i did do the motor on the side until its ready to go in that way you have your car most of the time.

if your on a budget go full 4ag harness i just started out with the bigport head and a AE101 map 4agze harness with dli but soon had to go stand alone it was easier and a little more expensive

or just get a 4ag full harness there on ebay alot the gts change over

About how much $$ does the total head swap cost?
What I was wanting to do was run the 4A head with the 7A harness and map sensors, without changing any if not much of the electrical in the car and just use the mechanical parts(head, cams, cam gears, ect..) while still running a complete 7A harness,MAP & ECU. and make adjustments for the additional air flow with my SAFC-II.

-dans_st+Sep 12, 2005 - 10:40 PM
What about ignition? ;]

The major difference between the two are the ignition systems. The 7AFE uses a dizzy with an internal coil, while the 4AG uses an external coil. Each are driven slightly different also... gear type versus slot type. If it were easy... people would be doing it left and right... however I will add... do a search for toyotaspeed_90 and read up on his 4AGE swap. He's running a modified 4AFE ecu...

As for costs... the head is rather cheap (25-100 dollars + shipping) but you also gotta consider intake manifold (50-150 dollars), distributor (25-50 dollars), exhaust manifold/header (50-350 dollars), pistons (50-400 dollars)... etc. The 4AG head has a LOT more combustion chamber room... so 7AFE pistons will make like 7 something compression with a 4AG head. If you're planning on going n/a... you have to swap over 4AGE pistons.

-dans_st+Sep 12, 2005 - 3:40 PM

before i answer this are you going n/a or turbo

because if your staying N/A fallen is doing the same might want to talk to him as to how much he has into it

turbo more money

now the route i took is on the spendy side because i upgrade everything
rods=700 turbo=700 stand alone=1500 Head and port work = 1000 turbo manifold+work= 450 injectors=300 there is an idea

This post has been edited by nik: Sep 12, 2005 - 6:17 PM

also if your looking for parts Bee AKA Kwanza26 is the man >>

I already have a turbo on my car and have a tubular B16 manifolf and my JGS flange should be in Friday I have my fuel system set-up with
1.Walbro 255 fuel pump
2.-6 fuel lines from tank
3.Aeromotive FPR
4.RC 550cc injectors
5. Apex-i SAFC II v2

Hopefully this should be more than enough fuel, As far as the external coil I would like to run it - BUT is the 4A a distributor-less ignition system??? I know that IF it is a DIS system there is no way to swap head without harness.

-dans_st+Sep 13, 2005 - 2:45 PM

the AE101 4agze was DLI and map the 4age red and blue were external coil and afm if you go and look on club4ag.com you'll probably find most of your answers

I'm 99% sure you need to swap harness with the head swap or go standalone the fuel maps on the 7af ecu even with piggy back need alot of fine tuning to get right and the difference in distributors and other sensors save your self a head ace swap harnesses

Is this a good start?

http://cgi.ebay.com/ebaymotors/Toyota-MR2-...sspagenameZWDVW

-dans_st+Sep 13, 2005 - 3:42 PM

link doesnt work

Sorry it is a "Toyota MR2 Cylinder Head 1987 MKI 4AGE AE86" is this a good building block to what I am trying to do?

how about go to www.club4ag.com and buy a smallport head and intake manifold off of one of them. Kwanza could probably get you one also... he seems to be able to get most anything. >>