bp vs sp cams

[Secks]

ok, call me a dumbarse, call me lazy for not searching every thread on this site, but im in a truck in the bush.
Why do i keep seeing corollas advertised with the small port motor with the big port cams installed? Is there a performance boost to be had with these, and if so, why? lift or duration differances?
I'm curious because i have a set of standard bp cams layin round that were my spares for an old trd ported head, and even though im not using the old head, maybe i can use standard BP cams?
Any info will be consumed.
cheers...
s-ecks.

[-GT-]

ok, call me a dumbarse, call me lazy for not searching every thread on this site, but im in a truck in the bush.
Why do i keep seeing corollas advertised with the small port motor with the big port cams installed? Is there a performance boost to be had with these, and if so, why? lift or duration differances?
I'm curious because i have a set of standard bp cams layin round that were my spares for an old trd ported head, and even though im not using the old head, maybe i can use standard BP cams?
Any info will be consumed.
cheers...
s-ecks.

Yes you lazy dumbarse, and yes it's because of slight lift and duration differences.

You ask me for the actual specs and you'll get called worse.

[Secks]

Specs dont really matter.... guess i'll chase up some adj cam gears and slap em in on the weekend or so...
Cheers mate.

[X kyle X]

i'd recommend measuring the cam lobes first tho..

as there is speculation that the first serious bigport (3 ribbed model) had the increased duration and lift and that the second serious bigport (7 ribbed) had the same cam profile as the smallport...

wether or not this is true is still open to conversation/debate...

but for what it is worth just measure them up..

and yes the lift and duration for both types of cam is readily available off the net..

[trdee]

The difference is in the duration (240deg vs 232deg) and the lift (7.56mm vs 7.1mm)

[Mr Revhead]

the ONLY person i know to have dyno tested this, had a LOSS using the big port cams.

kyle, i cant remember the out come,l but i looked into that some time ago.
cant remember if it was on here or another forum i posted the results.


easy enough to confirm anyway, just look at the EPC

[Mr Revhead]

the ONLY person i know to have dyno tested this, had a LOSS using the big port cams.

kyle, i cant remember the out come,l but i looked into that some time ago.
cant remember if it was on here or another forum i posted the results.


easy enough to confirm anyway, just look at the EPC

[X kyle X]

Well I had WSID tested mine, with a smallport engine I ran a 15.8 second pass, installed BP cams, the next week I ran a 15.5

But I suppose u can take the above on very little, as it was a different day and different conditions... so I wouldn't use that as hard evidence lol

[Ben Wilson]

as there is speculation that the first serious bigport (3 ribbed model) had the increased duration and lift and that the second serious bigport (7 ribbed) had the same cam profile as the smallport...

I've measured cams from an AE82 bigport and a smallport and I couldn't detect a difference. The AE86 cams might be different.

[X kyle X]

yeh ben I have heard that before aswell, which is why I stated that the different serious of 4age have the different cam specs, im not qouting this as my truth just as what I have read.

1. 3 ribbed bigport 4age (found in early aw11, ae82 and ae86) - 7.56lift 240 duration

2. 7 ribbed bigport 4age (found in later model ae82 and maybe later aw11) - smaller cam 7.1 lift 232 duration

3. 7 ribbed smallport 4age (found in ae93 sx) - 7.1 lift 232 duration

Im open to more debate about this as I find it hard to believe toyota would change the duration between the bigport models, but there is also speculation that the later bigport 'supposedly' made 2 extra KW

[Hiro]

the ONLY person i know to have dyno tested this, had a LOSS using the big port cams.

kyle, i cant remember the out come,l but i looked into that some time ago.
cant remember if it was on here or another forum i posted the results.


easy enough to confirm anyway, just look at the EPC

Peak power loss doesn't mean a loss of power though, could just shift it slightly lower.

[trdee]

ive seen dyno graphs from two people swapping bigport cams into their 4agze and they both gained ~5kw

[Dimitri]

the ze cams are smaller again. itd be an almost worthy swap in that case, but for the time it takes, i personally would not bother.

it takes a long time to do and you will need to buy shims ( typically about 1/2 youll be able to swap around, the rest youll need to buy, i got away with 5 when i did it).

[Talasas]

We swapped a head on a mate's Smallport for a cleanly built one with Bigport cams, after a clean tune with an eManage he gained 16 kW at the wheels. That is with the stock cam gears. The reason you'll find it's hard to get results from people is because very few can justify swapping 1 item that's so time consuming and getting an average dyno reading for a before and after. Often we tend to bundle the jobs into one so we swap several things at a time while x and y are removed/apart etc.

[-GT-]

Peak power loss doesn't mean a loss of power though, could just shift it slightly lower.

Do you perhaps mean;

Peak power loss doesn't mean a loss of torque though, could just shift it slightly lower.

or;

Peak power loss doesn't mean a loss of mean power though, could just shift it slightly lower.

because i think you'll find

Peak power loss does mean a loss of power.