Ariel.Club Forum

I dunno...porting has always worked for me,no matter what the engine.Granted,too big is just as bad as not big enough. A happy medium!

If you dredge up the GM tunerzine PDFs on the 1000hp Ecotec builds the "ported" ecotec heads flow about as much as the stock K20A heads.  It's very easy to get K20A heads up to 350CFM though porting.  And yes the ecotec ports are tiny bt they don't have to be very large when you foce feed the intake side. :shrug:

I ported the Focus head,it dropped 2psi of boost (twin screw blower) and gained 35wtq.No other changes.Not even the tune.(measured on the exact same dyno) 

Similar gains with other cars as well,so porting is im-port-ant...

I have read that.  Boost is not necessarily hooked directly to power, ... we shall see

The positive displacement blowers like the TVS Eaton/Harrop and the original roots Eaton are not very good at "pushing" air through restrictions,where a turbo can overcome this, as it is unlimited in how much air it can move as it is not linked/limited to engine speed directly. I honestly believe you will see a significant gain in torque with the head ported.I have personally seen it in a few of my own cars running superchargers.No other changes other than heads/intake/exhaust all ported and port matched and the torque gain was amazing. I actually had a drop in boost pressures,with the torque gain. Strange,but true.

[quote="MadMaxAtom and company"]
You running the 2.95" pulley on the TVS,and Shinoos exh?
[/quote]

2.95" and Fortress exhaust (not restrictive at all and loud)

You running the 2.95" pulley on the TVS,and Shinoos exh?

Mark, I would like to be optimistic that you are correct, however, the torque curve is super flat and peaks usually come early.  If you look at a turbo torque curve the added boost that a turbo can deliver down low just makes numbers that you are not going to catch with a direct parasitic device.  Turbo is still the way to make power it just depends on the users tolerance for lag and they are getting much better at that, as you have said.

That is probably what is affecting your torque numbers,I would bet on it. With a well ported cyl head,you should be in the 350whp/tq range. Damn..that would be plenty for me.

My belief is that they did the minimum amount necessary and walked away from the ports.  The problems arise when you force more air in.  On my hp curve you can see a spot where it just sort of flattens out from not being able to more air effectively.

I have a friend that ports also,and is quite famous among northeast racers,who lives right down the road..hmm.  No...I'll wait till next year when I upgrade the pistons etc.Don't want to put too much pressure on those stock pistons. I'll do some blower cams at the same time.Nice fat torque curve is my goal.  I am amazed how well the stock head flows,according to the link you supplied.

I am not going to say I told you so, .... no wait that's next year!  Told you so, I need to get off my a** and get a spare head to the friend the head portin' guy.  If you want CNC port work M2Race would be the one...
http://www.m2race.com/product_specs.asp?ID=5

Considering GM calls the Ecotec the next "small block Chevy"performance motor,they sure did strangle it! Even the head exhaust runners are tight. I'm not going to pull the head and do a port job now,but believe me,it will be on the to do list for next year.Wow. I'm sure the GM 1000hp motors head ports are opened up..a LOT   :H:

You have to love motors that to some degree are bottled up from the factory.  It gives us all something to do.    heh.

It is amazing that they would strangle that side so bad ...