D0OE exhaust ports

[travis]

Increasing the bowl radius ( cutting out the taper as the bowl drops down to the guide) on the back side of the valve bowl down near the guide is a sure fire way to drop off low lift flow and add pulses into the flow at certain lifts, that on a flow bench can be heard and seen in the test pressure bouncing up and down.

Have you had this head flow tested yet in stock form?

I only cleaned up one cylinder, and took the sharp lip out of the short turn and blended the bowl a bit. The factory taper is still there. Should have these tested this weekend

[PRH]

How I would have gone about the exhaust is.........

-Test as is
- test basic bowl blend
- remove emissions bump, retest...... see if it’s worth the time to mess with it or not.

[mag2555]

Here's my flow test of these stock E7TE Exh ports with carbon, rust and all, and then a test of then just cleaned up by means of a 80 grit roll with no blending done, but the the air injection Boss ground away.

Stock valve flowed @28"

.050". 18.3
.100". 37.6
.200". 76.2
.300". 101.3
.400". 109
.450". 110.7
.500". 111.4

Flow test of cleaned out port with air boss ground away.

.050". 18
.100". 37.5
.200". 78
.300". 110.8
.400". 123.3
.450". 125.5
.500". 127

[Carnut1]

On the power porting thread I posted some E7 cutaways that are helpful. The backside of the exhaust bowl is very thin. Thanks, Charlie

[Carnut1]

$T2eC16J,!)EE9s2ufWcHBSGzyR,ujQ--60_1.JPG

I dug up that cutaway, you can see how limited the bowl is. Lots of metal on roof and ssr to work on.

[PRH]

Here's my flow test of these stock E7TE Exh ports with carbon, rust and all, and then a test of then just cleaned up by means of a 80 grit roll with no blending done, but the the air injection Boss ground away.

Stock valve flowed @28"

.050". 18.3
.100". 37.6
.200". 76.2
.300". 101.3
.400". 109
.450". 110.7
.500". 111.4

Flow test of cleaned out port with air boss ground away.

.050". 18
.100". 37.5
.200". 78
.300". 110.8
.400". 123.3
.450". 125.5
.500". 127

Wow....... those things are pretty weak ootb.

Getting the ex into that 150cfm range should be more than adequate for the power levels you’d expect to see from the type of combo heads like this would typically be used on(call that 300-400hp).

[mag2555]

The stock Exh to int ratio is not that bad coming in at 72.5%, with the air injection boss gone and the 2 minute port clean up it hits 84%.

[mag2555]

Here's the 3rd flow test that I did not put up the other day .

.050". 19.3
.100". 37.8
.200". 77.5
.300". 111.5
.400". 125.4
.450". 127.6
.500". 129.8
.550". 130.6
.600". 131.3

I only put in 4 minutes worth of time so I was not expecting much change , and it turns out I was right, lol!

For this test I blended out the upper part of the cylinder side wall from the change over point of the bowl and runner out to the flange.
Cut back that cylinder wall side of the valve guide & used a long strip of 80 grit paper to blend in the short turn a hair.

Next up I am back to the Intake side if I have time tonight.

Charlie, thanks much for the cut away photos, and yes that nice thick meat on the short turn should make for a great chunk of added high flow by means of larger valves for sure!
The rework looks like it could make for a added .050" of short turn height.

I also plan on tapping the air injection hole for a Aluminum bolt to thread in so I can close off that ditch in the roof.
It being there is not a issue now with the mostly unstreamlined valve guide sheileding it , but it will be once I boat tail the guide.

Looks like stuffing in a 1.55" or 1.60" valve with the needed port work should make 180 to 190 cfm doable with good strong low lift numbers.

[mag2555]

So I did a bit more Exh side work on Saturday and a lot more on Sunday Travis.

1.450" valve @28"




.050". 18.3
.100". 37.9
.200". 77.4
.300". 115
.400". 128.9
.450". 131.5
.500". 134.4
.550". 135
.600". 136.7
.650. 137.4
.700". 138.2

Then since I knew I was at the point where gett more high lift flow above .400" lift was going to cut into the other flow numbers I had I stepped up to a 1.60" valve size.
I would have liked to go to a 1.50" or 1.55" valve but I had non on hand .


Flow test , 1.60" @28"
Note that this test valve is Tuliped and has a .030" 30 back cut.
I reworked the port to make the best use of the above valve shape factors.
Pictures will be forth coming as my free time was short both days, sorry!


The second column is for change over the stock 1.450" valve, the third column is flow change over the last flow test.
.050". 23.6. 5.3. 5.3
.100". 53.7. 15.8. 16
.200". 110.4. 33. 34
.300". 137.9. 23. 36.6
.400" 141. 11. 32
.450". -------9.5. 30.3
.500"---------6.6. 29.6
.550"---------6
.600"---------4.3
.650----------3.4

[GARY C]

Does anyone have any dyno data on these heads?
Preferably stock vs any mods surly there is something out there?

[travis]

Does anyone have any dyno data on these heads?
Preferably stock vs any mods surly there is something out there?

The very limited amount of dyno data I have found on the ‘net shows home ported E7’s, with no other changes, can be worth 25-40hp with thoughtful porting and other supporting mods already in place (intake, exhaust, cam, etc).

I think the lack of dyno data is for one or 2 primary reasons...either it is a budget build and dyno time usually is far outside the budget, or it is some sort of top secret class rules type build

[GARY C]

Does anyone have any dyno data on these heads?
Preferably stock vs any mods surly there is something out there?

The very limited amount of dyno data I have found on the ‘net shows home ported E7’s, with no other changes, can be worth 25-40hp with thoughtful porting and other supporting mods already in place (intake, exhaust, cam, etc).

I think the lack of dyno data is for one or 2 primary reasons...either it is a budget build and dyno time usually is far outside the budget, or it is some sort of top secret class rules type build

I am guessing most of the stuff done and published with these were pre internet days.

[PRH]

I’m sure Bill C has some dyno data on them....... but it might be in that “top secret” file.

[BILL-C]

I’m sure Bill C has some dyno data on them....... but it might be in that “top secret” file.

I promise i will dig up some dyno sheets for you, just need a little time to deal with some problems at work. One of our brand new C6FE castings turned into a lawn sprinkler on dyno and had to start over on another set. Just put in a 14 hr day and have to get right back after it after a little sleep. Gonna be a few days before i have any play time.

[gmrocket]

It would be nice if someone had some actual power numbers instead of just what flows better, I think it has been established over and over that exhaust flow numbers and bigger exhaust valves rarely equate to more power. You will find several race heads on the market that have a 1.55 exhaust with a 2.225 or larger intake valve which also blows a hole in the Int to Ex percentage theory...

Does that still apply if it's a 9:1 engine or 15:1?