Quick Question On 4Age Bigport Cams &ecu Into A Small Port

[ke35 dan]

Hay, so I've got a small port 4age in my 35, but just picked up a bigport head and ecu for a case of beer. Has anyone run a small port engine on a bigport ecu before, also somewhere on here I've seen someone running a set of bigport cams in a small port, are the bigport cams better?

Thanks in advance, dan

[ke35 dan]

So no one on here has ever done either of these mods? I mite just get a microtech then

[ke70dave]

I didn't think that the difference in the big port and small port cams was enough to warrant swapping big port cams in?

 

You will have to adjust the shims if you do swap them.

 

Here is a thread that discusses this:

 

http://www.toymods.org.au/forums/tech-conversions/36502-4age-big-port-cams-small-port-head.html

 

The smallport distributor is different than the bigport distributor so you won't be able to just plug it in. The smallport has a higher compression ratio, the bigport has TVIS. I thought the injectors were different too....

 

I wouldnt be trying to make it work, it will most likely cause more troubles than its worth.

 

What is wrong with your smallport engine as it is?

 

The smallports rev go harder in the high rpms than the bigports, but the big ports have more grunt down in the lower rpms.

[B.L.Z.BUB]

Supposedly the cams have a slightly longer duration but not really enough to warrant the swap.

 

Like Dave has said, using a BP ecu on a SP is going in the wrong direction. Plugs, injectors, dizzy everything is different and your engine will run worse.

[ke35 dan]

Thanks guys, there's nothing wrong with the small port, it just didn't come with an ecu . I just have a complete b/p ecu and loom & a 20v silvertop loom & ecu, between the 2 I can match up all the s/p plugs. But all good I'll just keep looking for a s/p ecu and uncut loom. Thanks again fellas, I'll clean up the spaghetti of wires next to the rolla now.

[ke70dave]

ah i see, yeah best of getting a small port ecu or go the aftermarket ecu.

 

here is one!

 

http://www.ebay.com.au/itm/4age-smallport-16v-ECU-AE93-E92-Corolla-SX-GTi-/171317808606?pt=AU_Car_Parts_Accessories&hash=item27e3564dde&_uhb=1

[Hiro Protagonist]

Supposedly the cams have a slightly longer duration but not really enough to warrant the swap.

One thing to remember is that there are two different types of bigport cams - the later model ones are the same as smallport (EPC even calls up the same part number) and thus wouldn't make a difference, it's the earlier ones with longer duration and higher lift that make a difference (tend to be found in 3-rib/bluetop bigports but all 4AGEs these days are old enough that who-knows what cams have been swapped in at some stage)

[B.L.Z.BUB]

^the hiro we need right now ;)