I don't have Sirio Sti engine...but I agree on his remarks on plus 12 engines

Agree... in fact needed to change my gearing to a 16/22 from 17/23 on my MTX4 and I play with the spurs to compensate the wear on the tires (this is what wake up really). Love the insane whine of the Sirio.

Rainer,

Never tried 12 + 3 so i dont know what the powerband is like with that motor, but what he is correct about is the 2630 pipe works very well with the Sirio motor 2611 also works well.

Hey Robert,

Have you tried the STI with the Skyline pipe? I tried the 2630 again but the power delivery felt quite flat (even after a retune). I'm going to try dropping a tooth on the second gear pinion to see if it wakes up with the 2630.

Dave

I run the 2630 with Short header on my STI with tall gearing and the bottom end grunt is awesome. Better than the 2611 IMO. On my MTX-4 i run 18/24 and 60/53, and it still light up out of the corners. The power deliver is far from flat on my car . Maybe even too abrupt.

Yes 2630 much better lower temps....the whole nine yards.... have you tried different head clearances with the pipe and different percentages to get a nice tune

Yes it is very good...

I run 20% with the stock shimming. Can I go lower on the head clearance?

Dave

On a short track, maybe but i wouldn't. They are shimmed for 16%. Also take into account that the 2630 is shorter than the 2611 so you will increase the chance of detonation if you lower the head clearance. What car are you running?? If it's an MTX-4, i can help you out with a clutch set-up.

I'm running 25% at 20 thousandths clearance ...i tried going down to 18 thousandths and started blowing plugs so i went back up....since you are running lower content you might be able to lower to 18 need to be very careful when doing this not to damage motor....hope this helps

i found stock gearing alot better but im running a SIR pipe.

um yes but i dont agree about the pipe and i will say i dont like the sti on a short track it kinda sucks BUT ON A BIG TRACK WATCH OUT BABY AND I RUN 16% with it for now.and he prob dosent crash hard so he dosent break cranks

Odd, on the local short track here, the Sirio seems to do ok.......But i guess i could be wrong.

that guys post in the 720 thread is very well done. He never once said one engine was better than another, he has explained the difference in powerbands.

I only run tall gearing because thats what my local track requires. Front straight is around 270Ft including sweeper, and back straight is around 180Ft.

It's a bit of a myth that the STI does not make much torque. Sirio engines in the past were more RPM motors, but EVO3 and EVO 3 STI dont lack anything in the torque department. Also, not all engines work with the same gearing and clutch set-up.

Agree... with such straights you need to adjust the gearing, but on my track, if you want to be quick, you need to have a serious holeshot coming out turns. Shifts are 5 or 6 (depending drivers and engines), less shifts and you're losing time, more and you're shot.

16/22 on my MTX4 is what gives me 6 shifts and does wonders, gas mileage improves with such short gearing.

Is a great engine, with torque, but love the way it rips thru the 1st gear with mind-blowing acceleration coming the hairpins.