My first flowbench test. 7MGTE

[Flannelman]

The head is out of a 87 Supra targa top. Rather large beast!

The work so far is on the Intake only.
Also, the work is on a floating pressure bench, not a constant state. Difference is, at low lift my bench has high vacuum and at high lift there is low vacuum.
My fault for the following flow figure mistake. I didn't have springs on the exhaust valves. This resulted in the valves being sucked off the seats, giving secondary flow path for air. It my have been only 0.1mm, but a leak is still a leak. It has skewed the results for the STOCK figure only. All numbers are in CFM (Cubic Feet per Minute)

STOCK INTAKE...................PORTED INTAKE

2mm.......89....................75
2.5mm.....98...................87
3mm.......111..................110
3.5mm.....117..................130
4.0mm.....124..................140
4.5mm.....130..................155
5.0mm.....142..................162.5
5.5mm.....163..................170.5
6.0mm.....167..................183
6.5mm.....174..................188
7.0mm.....177..................196
7.5mm.....188..................201.5..........Stock cam peak lift point
8.0mm.....195..................204
8.5mm.....200..................206
9.0mm.....203..................207
9.5mm.....205..................209
10.0mm....207..................210


As can be seen in the lower lift points, the exhaust valve opening has altered the results.

Effectively, I have filled the floor of the port, straightened a wall, removed material from the valve guides and performed de-shrouding in the combustion chamber.

The port modification I have made is best explained like this

Stock Port Opening Size........... 2.616Inch2
Modified Port Opening Size....... 2.093Inch2

The ports have been filled a great deal using Devcon Metal Putty. Its a 2 pak metal filler

What has me wondering as to what this work will do when the engine is built and run in. It is to my understanding that airspeed is torque. The flow number is about power potential.

Stock air speed @ 7mm............162FPM (Feet Per Minute)
Modified air speed @ 7mm........225FPM

Not only has shrinking the port size increased total airflow, but airspeed has risen sharply.

Only time will tell when the supra is strapped to a dyno will this modification show its true worth in a turbo application.

Thought this would be an interesting read for the Gearheads on Toyspeed.

[blackmk3]

Very interesting read

I assume your going to complete a retest with the exhaust sealed up?
Interesting about the port speed. Ive just finished porting the head on my 7mgte. The intake ports are huge and i wondered if they were to big.
I basically just cleaned up the casting marks and opened the divider up slightly in the intake.
Exhaust got opened right up.

Do you have any pictures of what youve done and the combustion chamber mods?

[Vertigo]

Think of it this way.

Higher airspeed into the cylinder means less power used pulling that piston down during intake, this applies at all RPM ranges, therefore more torque. Theoretically there will always be a limit to how much torque you can free up with airspeed.

Higher flow means greater amounts of air is able to enter the cylinder if needed. That works out to be at the top end of engine air requirements, which is wherever on the RPM range you have tuned your setup, whether this be through intake runner length tuning or force feeding.

[Flannelman]

Photos... Was in a rush. Post these later

The setup is essentially stock internals (just my port work) with bolt on upgrades. Largest change comes from aftermarket header system to a single aftermarket turbo. 750cc injectors and link g4 storm

My understanding of airspeed is it comes into effect in the latter part of the intake cycle. With speed comes momentum which fills the cylinder after BDC. Increased speed=increased ram effect. As the cam is unaltered, I would imagine that when the valve is slammed shut, it will generate a greater wave pulse in the intake tract. Whatever stock lengths are tuned for will be amplified.

Exactly where and what the torque/power curves are going to do, only a dyno will answer

[Vertigo]

When the intake charge is compressed, I can see how it might impart some force on the piston, but not when there is a partial vacuum, as in NA applications.

[Flannelman]

Modified Combustion Chamber (head needs a skim to bring the compression back up)





Stock port 7MGTE





Crappy photo sorry... Modified port, Clay used as its a good price and easy to work.





Stock valve guide area





Modified valve guide area (big flow increase)





Side by side view of ports, stock/modified



I can't do a retest of the stock port as I no longer have a Stock port to play with

[blackmk3]

Interesting work. What have you decided to do with the exhaust?

Found this article, you may have come across it aswell reguarding the casting diffrences in the intake of 7mgte heads dependant on year and purpose
http://users.tpg.com.au/users/loats/tec ... ences.html

[Flannelman]

I haven't seen that article, but have read of the #9 and #11 differences. Always wanted to know, thank you!

Exhaust is very similar to the 4age 20v. From what I learnt there I will apply to the 7M. I expect to break 155cfm at peak lift as the valves are bigger on the 7M

[Flannelman]

Stock exhaust flow Vs Ported (test was backwards, Vacuum applied to port and drawn through from cylinder)

Lift----------Stock-------------Ported (In CFM)

2mm.........71...............74
2.5...........83...............96.5
3.............103..............106
3.5...........110..............114
4.............120..............122.5
4.5...........128..............134.5
5.............132.5............138
5.5...........136..............143
6..............140.............154
6.5...........145..............156
7..............149.............162
7.5...........151.5............166........(stock cam lift point)
8.............154...............168
8.5...........155.5............171
9..............158.5...........173
9.5...........159..............174
10............160..............176

Not as big a gain as I would like, but 10% isn't to be scoffed at.

Material was removed form the roof, forming a V rather than a Y. The walls were blended into the new roof line, but the basic Y shape was left on the floor. The center branch was reshaped to give more room around the guides and improve the transition of the two valve bowls. Port exit remained the same size. Combustion chamber side saw minor deshrouding.
This work could benefit with a larger exhaust valve.

Best thing is the owner has brought back the stock gear. So the dyno will be showing what the head work will do on effectively a "stock" engine.
Only difference (that I know of) is ARP head studs and HKS 2mm metal head gasket.

I will give the full rundown when its dyno time.