bigport or smallport

[rthy]

should get dyno sheets up

[Nikkojoe]

Just so you know, its 88kw for an ADM bigport 4age (and later aw11's with afm). JDM were 96kw for a bigport. All the diff was the ecu (one is tuned for higher octane petrol).

A smallport is newer, has 7rib block and slightly higher compression. In many ways its similar to a gze, just the pistons are forged and lower comp on a gze.

IMO a fresh bigport vs a fresh smallport will not have much in it, nor will you notice the difference. The power levels could easily be altered with simple bolt ons. Who knows, the 100kw quoted engine power output could have been achieved by a better exhaust design, could easily make up that 4kw.

[Rian]

96 kw as you said came out with the jap tune for high octane 105 or watever it is...

while the 100kw came out here tuned to our petrol/domestic market.

id think thered be more than just 4kw in it.

[Nikkojoe]

True, but the smallport doesn't benefit (to a limited extent) with higher octane petrol if both are run on stock ecu. Smallport will always be marginally better, not too much in it. I would go a smallport if its available and just going to stay stock. As for a developement engine, a late model 4age bigport (found on late aw11 and s1 ae92) would be my choice as it has a 7rib bottom end.

[slydar]

its quite a noticeable difference from my first hand experience. ive owned 86s with both engines.

the small port is better in almost all situations. the "big port is better for turbo" thing is also wrong.

turbos compress air. they dont "blow" it. so.. you still want the superior flow of the small port, to flow as much compressed air as possible.

also, the difference isnt just port size. the small port has a much better short turn radius.

just have a think about it.. do you really think toyota would update to an inferior design?

small port is newer and better, its as simple as that.

the only time a big port might be worth considering is a really really high hp engine. like well over 200hp NA and like, well over 350hp FI.

obviously though, we are not always spoiled for choice, and big ports are still good motors.

[markiitourerv]

For street use the smallport would offer better drivability.

As a bonus, the smallports use a map sensor instead of afm, so intake mods are easier.

[.ady]

mainly using for street use. getting really positive stuff out of the smallport now after this thread....might go and jump into one and see what its like...

[DRFTR86]

me and a mate on here (fatke) when we built are n/a motors, he had a small port and i had a 7 rib bigport, for kicks, we swapped the heads, both p&p, same cams, same valve springs. so mine was a 7 rib bigport bottom end, small port head, quad throttles, his was smallport bottom end, bigport head, twin webers, and i can safely say his engine takes the cake, even tuned by the same tuner, but before all the mods and hybrid integration, for street use you will be fine with the smallport, killed my bigport day in day out

[.ady]

how about 3 rib big port bottom end with small port head and quads?

[Arch]

+1 for smallport

slightly higher comp, 7 rib block with oil squirters.

revs harder esp in the top end, no point ever revving a bigport over 7k, smallport usually good power to 7.3k, also they are newer so you can usually still find good ones. obviously harder to find with your rwd manifolding, but sitll pretty easy these days