OMG that one for the three main problems with these motors others are cooling head and carb. The ramp isn't a issue run it as is save your money don't fix it you wont see a difference.

Also if anyone needs a brand new cooling head Extech NIB let me know will sell cheap.

So the piston and sleeve will also fit in the extech's

Yes.. Bur keep in mind that the Bore and stroke are slightly different between the 2 engines.

so... what happens if you use a slightly shorter conrod in your engine?

I think the sirio ,orion , werks ,use the length rod right now i'm using a sirio evo 4 sti p/s ,rod,case and a werks b5 crankshaft and engine runs good. Will see if any better or worse when i race this weekend.

Thanks for te info mate!...., i guess that i will get the kanai3 engine rod from my friend..

The Rods are the same length from Sirio & Trinity.. But, rod length Does not determine your Stroke.. The Crank determines your Stroke..

The answer to your question, how ever, is it will change port timing.. Which could be good or bad, depending on which way it changes, and depending on your driving style.. I'm not a tuner, so I don't know which way will do what. One, thing I do know for sure if you only change the crank to a shorter stroked crank, you will loose some compression, same would be true if using a shorter rod.

sirio cl7 sti and the evo4 sti use the same rod [ same part number]it all about the crankshaft stoke. I gained the compression by removing a shim and i will watch it close. Not for beginers. 16.62 evo vs werks b5 16.50 crankshaft

Has same bore and stoke so it should fit.

And the rod is the same size if so im gonna order a re-generation kit but not sure which one to order cuz there are 2 different one's on team epic/team trinity website

Port timing will be your only achilles, and depending on which way it moves it, it might actually fit your style of driving better..

I have a STi Evo 4 that needed new crank, I have a werks B7 I was considering swapping into, it, but decided against it, becuase none of the modders or manufacturers would give me any idea how well it would work.. one said it coudl either increase bottom end or loose bottom end.. Considering I wanted more, it was a gamble I decided against.. I ended up with a nice used RB S5, and am glad I got it..

Trial and error, my crank is wearing at the pin on my evo4 so that why am trying the b5 crank because its close .You cant find part on a sirio 4 sti anymore and the b5 crank has hardly no wear so what the hell.BTW the evo4is the best engine I have ran.I wished they still made parts for that engine,very smooth and powerful at the same time.

+1 my evo4 sti engine is bad as hell.. but my eb full mod extech runs awesome as well.

We re-fill the cranks on a lot of Sirio trinity engines, They are notoriuos for the epoxy coming out. We charge $15 you can run it without, like another member stated ,but it will run better with the epoxy in. With the epoxy out it enlarges crankcase volume, so you will lose responsiveness and a bit of runtime.

Lance,
Rcrenew.com

One of my Evo4's is doing this as well, which is why I was considering using the Werks crank as well.. BUt you will have to run a Werks Rod.. And, I am not sure if the wrist pin is sized different from sirio to werks or not.. So just beaware that you might waste the $75 for a rod for nothing..