SMG

For those of you that were interested, done some tests on heads today, heads tested WRC ported head from Japan, did not think it looked that great and it wasnt. Flowed air uptill .450 but max flow on inlet was 152cfm head stopped flowing air at .400 as far as power is concerned. Exhaust was better 127cfm at .400 lift max flow 132cfm at .500. Tested MY00 head std, very good 159cfm at .400 after that no real gain in flow/power. STD ex port flows 114cfm at .400 so room for improvment here. Im hopeing i can get the ex to flow 135/140cfm at .430 as you can guess the more air flow through the ex port the more gas to spool the turbo. The objective of increasing flow through the port is to get better gas flow at low lift as well. A good step would be to run a .400 lift inlet cam as flow is great upto .400. For those of you who are after big hp a head that flows well until .450 is the objective and a cam to match. High flow heads and high lift cams have prose and cons, may be we will go into this more later. Next to be tested will be std MY95 and one of my high flow MY95, then high flow MY00, then some work on std and ported manifolds. I will at some point show the complete flow graphs of all heads. Steve.

UkLegacyT

steve, i was one of those that spoke to you about this a while back, have mailed you off line mate

ian

David_Wallis

Any chance of some pics of the differences between heads and ports??? (Mail me offline if you prefer not to post?)

David

SMG

Ian YHM,
David i will post some pics, but will not be until next week.

Flow results on STD MY95

.300 lift 134.7 cfm
.400 lift 140.9 cfm
max flow 142 cfm

Flow results on ported high flow MY95

.300 lift 143.2 cfm
.400 lift 169.5 cfm
max flow 172.4 cfm

Some good improvments here and with the right cams will make a big difference.
Steve.

.400 lift 169.5 cfm

David_Wallis

I await your posts!!!

David

Adam M

nice work SMG,

and very important.

Looking ofrward to seeing what you can achieve.

Trout...

SMG - will you be doing any work on Sti V heads? And what is the lift of Sti V cams - do you know the profile?

Excellent work!

Trout

Cosie Convert

Good stuff, you don't see much of this type of data posted.

One thing not to lose sight of is port velocity, it is possible to reduce this too far by using big ports. This can hurt performance, particularly in the mid range.

Quite difficult to quantify head modifications without back to back dyno traces.

Andy

Silver Wings

Steve

Gotta be boring here - but I was the manager of the 'flow bench' in one of the world's top engine design companies...ooooooo I hear you say....and the main thing was how the heads performed on a dyno rather than on the flow bench. The reason being that swirl and tumble of the fuel/air mixture in the cylinder can be more important to the combustion process than the pressure drop in the ports, especially in a turbo.

Have you or are you about to produce results from a dyno or rolling road to show the improvements?

Colin

SMG

I agree with all comments made, and RR tests will be done , i dont inlarge the port a great deal just reshape and this is were the main gain is, the air flow gain in the port is only as good as the cam you run with it ,std scoob port is large to start with so no real gain in going bigger. Valve throats are small at V/seat and restrictive, on later heads the v/seat area is less restrictive and gas flow is greatly improved. lets say you port your head and the flow under .200 lift is similer to std a little better at .250 and at .300 and .350 .400 great improvment, if your running your std wrx cam with only .310 lift, your gains will not be great but if you raise lift .400 the benifits will be greater. Lets not forget the basics bhp is a figure that you get from a torque reading, and you get more torque from getting more air into the cyl, hence the turbo. Im just scraping the surface with the imformation ive given you here, and there are many many things to consider. With cams check valve to piston clearance i run a min of .050 , check valve springs are not coil bound at full lift .050 between coils if youve recut v/seat is fitted spring hieght correct etc etc.This imformation is free and and intended for your benifit and interest olny, i will help with what i can, and hopfuly prevent mistakes that are all to easily made and can be expensive. I use a super flow, bench with flow com and port flow analyzer v3 with temp correction. I will be doing some port velocity tests soon.
Steve.

David_Wallis

Sounds interesting... a bit over my head.. but sounds beneficial to beat you andy!

David

Tim_K

Hey Stevie G

I wonder who's head produced 172.4cfm then?

SMG

hhhhmmmmm i wonder.

SMG

Trout i think your port is the same as my00 design so i will be doing some work with these very soon. I have about 10 heads from veriuos years and models and have seen about another 10, some were sti. There seems to be 3 veriations of port but only 2 are common, head type should be identifible by inlet manifold flange.O/E cams ive measured so far have been wrx .310 later engine poss sti .335
and a pair of cams from a competition engine that should be std but someone may be cheating, they were .370.Valve timming figures on std cams, inlet opens very late this will benifit low down torque but effect mid/top end power, and overlap is very short.