crossflow porting results

[gerg 10,871]

Yeah nice gentle transition from runner to throat but the port opening seems smaller than the valve pocket. Call me stupid but is that less than ideal? I always thought the biggest restriction should be at the valve, or has that line of thinking changed now? Not much meat in the port roof but you could take a bit out of the floor I guess (if you wanted to open it up)

[ando76 4,354]

Current trends are to an hour glass inlet shape when viewed from one end of the inlet tract to the other. The smaller port creates greater air speed which maximises low lift gains and gets the air happening so it pulls past the 'restriction' in the middle when it hits high lift.

That is to say you will see air speed(cfm) drop off at high lift in a static situation (flow bench - constant pressure I.e 28hg) but in the real world the engine, particularly on those with good exhaust system design, will pull way harder than the bench.

Having a nice big opening at the valve with good throat diameter and an awesome seat cut and then selecting a cam profile to suit all leads to more efficiency than the old big hole - flows good syndrome. IMHO

[ando76 4,354]

I should add that my THOR cyclinder head that Cam and I collaborated on subscribes to this theory and flows well over 220cfm at .500" lift and keeps going to .600".

All with a stock initial inlet tract and I mean stock. It has just had the rough castings removed with a bit of 120 grit. No porting what so ever.

[wagoon 2,429]

I have just had my bargin cylinder head flowed after Cam at Engine Enginerring did his thing while I got a full engine rebuild at the same place. Keep in mind when I bought the head it had runner work already done and was for a 2 barrel speedway application. My setup is street/circuit racing 4 barrel soild roller cam with Inlet 256@50thou and exhaust 265@50thou. The head was flowed on the same bench by the same operator.

 

Flow figures literally the day I bought the head  

             IN               EX

100     52.605       43.42

200     105.21       83.5

300     153.64       100.2

400     192.05       119.405

500     209.58       131.93

600     197.06       133.6

 

Flow figures after Cam did combustion chamber and valve seat work only. The valve seat has a 5 angle cut.

              IN               EX

100     59.285       44.255

200     120.24       85.17

300     176.185     119.405

400     209.585     143.62

500     218.77       158.65

550     209.585     161.99

600     207.915     163.66

 

[ando76 4,354]

Look at the gains right throughout the range.  The man is a guru.  Thanks for posting them up Ryan.  Can't wait to see this monster together.

[wagoon 2,429]

Yeah Ando, I like the fact that my head now has as much flow at 400 and 550 as it at peak before without slowing down the air speed. I need torque for punch out of the corners and the way Cam has worked the head it will have loads of torque down low. I am not expecting high horsepower figures but I know it will have stupid amounts of torque, which for me is where the fun is.

[gerg 10,871]

The exhaust is the big winner there, very impressive!

[Clevo120Y 815]

Them good results fellas, I need to find the secret seat profile LOL

[slydog 7,873]

There still just numbers on the internet...need to make it go bro

[ando76 4,354]

Yeah Rob it is happening, not as soon as Ryan would like, but it is happening. 

 

Stay tuned for late November..............

[wagoon 2,429]

Thanks for rubbing it in that its not running yet Sly. Worst part will be the engine will be built and just be sitting in the shed waiting till I get the rest of the stuff I need.

[slydog 7,873]

I did get asked why mine picked up so much ET and MPH @ AFF drags a fair few time's and this is why...the cly head.     

[slydog 7,873]

First it was flowed no manifold for a baseline then it flowed with manifold on after mods. Yes not massive numbers but proof is in the results. 120.6 mph and a 11.5 ET. Any engine no matter what it is wants good cyl head and percentages and theories mean jack on a straight line engine. This car is actually better to drive now too which most said it would suffer but as the norm with this car it's the opposite. Valve sizes stayed the same (1.92 inlet and a 1.56 exhaust) all that happened was the ports and CSA was made bigger and followed manifold angles into cyl head.

So where doe's this leave SLY250? Not finished as I'm sending another cyl head down to be ported and set up for the current combo. My guy did find 11cfm thru clay in the chamber testing so we have room to go forward there along with getting more aggressive in the ports around the short turn. Issue is there's water there as Jase Stoodley can vouch for,but again it's HP waiting to be tapped into.

Props go to Ricky Naughton of LHT Race Engines for the prep and port work.

[ando76 4,354]

Nice solid gains without destroying low and mid lift figures. Ricky clearly knows what he is doing and the results do speak for themselves. Well done. 

[ando76 4,354]

Of course the engine also had an increase and compression and was run on race fuel as well so that has some bearing on the improvement in time and mph, obviously not as much as the increased flow but still a consideration. 

[gerg 10,871]

Getting a small port like that flowing the numbers is no small feat, granted the standard shape is actually pretty good and outflows the bigger 2V Clevo, but the ported results are up around 4V figures, and are more than what I've ever read about from any ported iron 2V (up around 250).

Also getting long-stroke motors to breathe is always a challenge.

Very impressive work.

The figures also back up the need for a decent roller cam as the flow flattens out sharply just after 0.550. Opening the valve much further than this would be pointless if that lift was from a flat tappet stick. The roller profile gets the valve open nice and quick into the max flow zone that can be achieved with that port, boosting area under the curve. It does this without going to a stupid cam duration and sacrificing dynamic comp in the process, which is where you'd be with a flat tappet profile.

Also backs up that age-old theory that the port restriction should always be highest at the valve (not the throat, as some have argued). Very impressive numbers!

Sent from my CPH1607 using Tapatalk

[slydog 7,873]

Next cam will have around 750-780 lift with 270ish duration to suit the combo.

Comp was actually already at 12.6 which was surprising. So only lifted .4. Next meeting will see the car tuned on petrol to compare fuels.

Next mod after would be nozzles in front of the throttle blades and new cyl head.

[Grimmy 312]

Knowing how fast your ute went with the before head gives me hope that maybe I can go fast with my little head lol 230cfm@.600

i can only dream of flow in the 250's . That's awesome ! 

[ando76 4,354]

Are there a before with intake on figures to go with this or just the bare head figures? 

[ando76 4,354]

2 hours ago, Grimmy said:

Knowing how fast your ute went with the before head gives me hope that maybe I can go fast with my little head lol 230cfm@.600

i can only dream of flow in the 250's . That's awesome ! 

Wazzys full weight xe sedan went 11.4 with a flat tappet and a generation 1 Barbagello CNC ported head. I own The same gen 1 CNC head and I have flowed it on Anthony's bench. Trust me, if you have 230cfm @.600 you will be fast. 

[CHESTNUTXE 7,311]

What would be a typical flow result on a std head ?

[CHESTNUTXE 7,311]

i should take my head and get it flowed to see where it stands,when i get it back.

[ando76 4,354]

18 minutes ago, CHESTNUTXE said:

What would be a typical flow result on a std head ?

If you go back to the very first page of this thread you will see Sean's test on a stock c1 head with a 3 angle seat cut. Stock figures would be slightly less than those. 

[CHESTNUTXE 7,311]

ok yeah i just saw that,to flow the head does it have to be bare or assembled or doesnt matter ?

[CHESTNUTXE 7,311]

im starting to catch on here ,so if you have say 210 @  500 it has potential for a real powerful engine,most of those other figures start to fall over around 600 why is that ando.