ttso

iTrader: (1)

Hi guys,

Anyone can explain the con/pro on AAC vs ABC engine? It seems AAC engine able to run at higher temp than ABC, is this correct?

disaster999

iTrader: (1)

bump

afm

Actually both platforms can run at high temps......but AAC can sustain better compression at those temps produced at high RPM's, and flame outs are less probable. At least that is my experience with Sirio's ABC and Collari's AAC engines.

AFM

trashcar

iTrader: (2)

AAC will not run at or take the overtemp abuse that an ABC engine can tolerate. At the correct operating temp for an AAC engine it will out perform an ABC engine due to the like expansion rates of all components. They do not tolerate high temps as it weakens the sleeve. Sirio is an exception as is Palmaris as I believe both are parent bore motors.

afm

Palmaris have BRB p/s, and have nothing in common with Sirios
Sirios are ABC only now, Collaris are AAC, both are made by Star Motors with Collaris made with their specs, like Nova based engines made by Novarossi.

Don't know of any other engine with AAC, so how do you say AAC sleeves weakens . My experience with early AAC Sirios and now with AAC Collaris ,is that they take more high reving high temp abuse than ABC.
AAC has better heat disipation properties than ABC, plus the better expansion rates.

AFM

trashcar

iTrader: (2)

Have two 421p aac sleeves split at ports niether saw temps above 240 both great running engines very high rpm. Replaced with factory ABC and head no further problems and will tolerate higher temps still would not recommend.Have tied palmaris BRB sleeve in r1wc works very well,the motor I was speaking of is his twelve with its one piece sleeve casting the new collari "sirio" is the same style.

afm

Ok you are referring to the .21 Sirio WCR, which has that one piece casting sleeve...
I'm talking about .12 Sirio's and Collari's, which have removable AAC sleeves, and have no problems.

So we can rephrase your statement, saying that on .21 engines removable AAC's don't work yet.......but they work fine on .12's for quite a while now.

AFM

trashcar

iTrader: (2)

Sorry for any confusion I was referring to .21 I guess I should have been more specific.

afm

No problem, on the contrary it's refreshing to discuss about AAC platforms, which are not so popular and have a lot of myths and taboos.
Papo

rahvintheevil

Well I just bought two Brand New Sirio .18 tx's for 60.00 for the first one and 80 for the second one. My question is are these True ABC or AAC? Also anyone have experience with this engine? I'm trying to put it in a Revo and it came with a tmaxx header unfortunately so now I'm left trying to find a header setup that will work, so far the os .18tm header I have will barely work if I jam it on and use an external rubber gasket and will probably work but its a tad on the big side and I would rather use what is meant for it. I knew about the scarcisty of parts when I bought these mills but opted to anyways at those cheap prices I couldn't resist.

So anyone who can answer if its AAC or ABC and also what I can do about a header setup for a revo for this.... and yes I tried the stock revo header pipe and it doesnt even closely fit, though I havent tried the platinum pipe yet and guess thats a possibility

Thanks

Roelof

The .18 is ABC...

We are busy with an AAC engine like the Sirio 2003WCR:



The main thing with AAC it the better cooling of the sleeve and that works a tiny bit on the piston too. You can run a hotter combustion without overheating the piston and a hotter combustion means more power.... Overheat on aluminium makes it softer and could low down the lifespan of the piston.

We have seen when a P/S set is at the end of life and fitting a new piston the lifespan of the set is shorter. The sleeve is weakening and expands more easy by the pressure of the combustions and the pressure of the pinch by the piston.

With this knowledge it is wise to take some time when warming up an AAC engine, let the heat slowly fight the cooling, do not force it.

Regarding Sirio, I believe the .21 onroad are the only AAC engines they make.

wingracer

iTrader: (24)

They don't have a .12 AAC anymore? I always thought it worked better on the .12's than the .21's

GMartinez

iTrader: (91)

my experience with the AAC & ABC
1 AAC break in take's more time to come in than the ABC
I could be more aggressive with the tune on ABC pushing the temp a bit
A friend of mine's rushed his AAC & pitted the top of the piston
AAC seemed to have more topend than the ABC also

wmay11

iTrader: (3)

Does AAC out perform ABC? And are the sirio AAC motors the way to go, I think they the only people that make .21 on road AAC engines?

Roelof

In theory AAC is better. But if it is realy better then all brands were making AAC