Just picked up!! SmallPort 4A-GE!, One Question???? Options

[94STcoupeKyle]

Hey i just now got home from picking up my 4A-ge its the 16 valve, i wish i could have gotten the 20v but hey i just about stole this motor, i got it for $75 bucks,

it only has 25,000 miles, its a japan spec 4a-ge.



What could i put on it to make it about as fast as the 20v









Please dont rag on me for being the 16valve, i kinda wanted to be original

This post has been edited by 94STcoupeKyle: Jan 31, 2006 - 9:00 PM

[94STcoupeKyle]

How much difference is between the smallport and the bigport?
like the HP and internals?

[Kwanza26]

How much difference is between the smallport and the bigport?
like the HP and internals?

There were two versions of the bigport... the 7rib block version and 3rib block version. The later (87.5-89) had the 7 rib blocks with 42mm rod journals as opposed to the older bigports with 3 rib blocks and 40mm rod journals. The newer big internal versions also used different piston pins, which were full float with clips as opposed to the older ones which used 18mm press fit piston pins. The older "smaller" internal versions aren't as strong as the much more stout "big" internal versions. I wish I can find pictures of the rods side by side to show the significant differences in size and strength... however, the side effect of the "big" internal version of the bigport engine was that it made less power because of the added weight of its moving parts. The good thing about it, was it was a hell of a lot stronger than the small internal version. The reason this engine was called "BIGPORT" is because of the intake design and the head's ports. Bigports used TVIS, which were a series of butterflys built into the intake manifold designed to increase intake velocity and in turn, increase low-end torque. Smallports, which came much later (1990+) eliminated this system. Bigports made anywhere from 112-127 hp depending on which ecu and metering system is used. Mechanically speaking... there is no difference between the motors besides the big and small internals. The heads, compression, etc, were all identical.

Smallports are just that... they have smaller intake ports and were designed to eliminate TVIS. Because TVIS was eliminated, they do have slightly less grunt in the low-end, but make up for it with a superior port design and higher compression. Smallports had the 7rib "big" internal block with high compression pistons (10:3:1). That's pretty much it as far as differences go. The rest is pretty much the same as the bigport. Smallports made about the same amount of torque as the bigport, however on a very different curve. They however, made more horsepower... between 130-140 depending on the ECU and metering system (MAP or AFM).

Visit Bill Sherwood's page for more detailed information...

http://www.billzilla.org/4agstock.htm

This post has been edited by Kwanza26: Jan 31, 2006 - 10:02 PM