bigport to smallport install

[sketchy]

Hello,

I am interested in installing the smallport 4age into my ae86 so doing some reading on how people have done this. I have a few questions that i'd appreciate some advise on.

One issue i have come across is the inlet manifold. The smallport (non t-VIS) engine is a FWD application and so the inlet manifold points the opposite way to the RWD T-VIS version. This needs remedying to complete a successful install!

One solution i have seen is to use the RWD inlet manifold but remove the T-VIS from the RWD 4age inlet and install the T3 bigport to small port adapter (https://technotoytuning.com/toyota/16v4a...rt-adapter)

The other method i have seen is to cut'n'shut the FWD non T-VIS inlet to work the other way round so the throttle body etc. does not point towards the firewall.

Does anyone have advise on advantages/disadvantages of both options? Of course i could go ITB, but thats a project for another day! At the moment i wish to keep stock ECU.

Presumably if keeping a stock ECU i would need to use the smallport one rather than bigport? Would the smallport ECU give me any problems with the loom/electrics for my ae86?

Thank for any input.

James

[totta Crolla]

I have done this and I am using a cut 'n shut inlet manifold.
The cut 'n shut is straightforward for anyone who can accurately cut and weld aluminium just make sure they get the angle of the throttle body somewhere
close to the TVIS inlet otherwise the TB can foul the bonnet.
You will need somewhere for the air temperature sensor to screw into and
you will also need to get some bosses welded on to allow fitment of the throttle cable.
It is all worth the effort and the smallport inlet is half the reason why the
smallport makes the power it does.
I used big port injectors in the smallport fuel rail and a big port ecu, there
were no problems with this.
The smallport ecu is completely different to the bigport and requires
extensive rewiring.
A spigot bearing will need to be fitted into the crankshaft, an easy job
just tap it in using a suitable drift.
Expect a couple of clearance issues with the water pipes and the
oil return from the head, easily solved though.
Bigport cams with adjustable pulleys are a worthwhile upgrade especially if you already have the cams.

[oldeskewltoy]

the smallport to largeport adapter may not line up. I recently showed what I did to make it fit properly....

http://www.aeu86.org/viewtopic/ost-019-c...highlight=


I have a smallport in my AE71 (similar layout to AE86) My manifold is slightly different from many... the entire top plenum was cut off the runners and reversed. This put the vacuum bits on the outside of the manifold. I did this because it made more sense in MY application

[sketchy]

Thats some great info, thanks for the direction.

Thats good news on the injectors and ECU.
I had read that the bigport cams had a more desirable duration/lift. I'll probably look to use these.

Given the 'fitment' issues of the big port to small port adapter, i think i'll steer clear and go for the cut and shut of the FWD inlet. Especially if this is a contributing factor towards the increase in power

Still deciding/researching on what options i have on the rest of the engine internals to use.

Now need to source the engine!

[totta Crolla]

You can also use the big port distributor.