differences in big port and small port oem cams

[jonny514mcl]

just wondering is the duration and lift the same on both these engines?

[jondee86]

According to Club4AG, the big port cams are said to have a tiny bit more
lift (7.56 vs 7.1) and a fraction more duration (240 x 232). However, even
though this swap is often recommended, I have never seen a post with
figures to prove that there is any measurable gain.

Where are the "Mythbusters" when you need them

Cheers... jondee86

[nzae86]

Hi there , I tried this swap and dynoed the car before and after with no other changes ,(smallport) and there was no noticeable gains to be had , so swapped back to the originals .The figures may be different between the two types of camshaft but maybe the head differences prevent any gain ?

[jondee86]

nzae86 Wrote:The figures may be different between the two types of camshaft but maybe
the head differences prevent any gain ?

Quite likely. Toyota will have optimised the cams for each engine. They
would have tested many different profiles before they settled on the the
one that best met their goals for the engine.

Meeting emission standards, and having an engine that worked well with
an auto trans, would have almost certainly been part of the design brief
for the smallport. Because, having lost the "sporty" RWD platform, there
was no longer any need for a "sporty" free-revving engine when the
smallport was being developed.

So yeah, hardly surprising that there is no gain when swapping cams. Bit
like when I put GZE cam covers on my smallport...

Cheers... jondee86

[ZDoman]

I had bigport cams in my car, I havent't dynoed it, so I can't say any results, only my butt dyno showed something But I can confirm the information from the club4ag, we have measured the cams and we found the same differences.

[Sam-Q]

I have heard reports of 3kw, I can't personally verify it though