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oldeskewltoy
oldeskewltoy UltraDork
9/3/15 7:21 p.m.

TRoglodyte
TRoglodyte SuperDork
9/3/15 9:52 p.m.

Witchcraft and magic, burn the witch . Such patience and craftsmanship are artwork, well done!

oldeskewltoy
oldeskewltoy UltraDork
9/8/15 6:47 p.m.

oldeskewltoy
oldeskewltoy UltraDork
9/16/15 3:22 p.m.

dotted line is short radius turn, below shown as a "negative"

cmcgregor
cmcgregor Reader
9/16/15 5:16 p.m.

These all look really really nice.

How much would it cost one to have this type of work done? I have a spare BMW M10 head (actually a whole motor) sitting around that I've been thinking of doing a mild turbo build on. I'd have to ship it to you, obviously, but do you have a ballpark figure for a fairly simple 2 valve per cylinder head?

oldeskewltoy
oldeskewltoy UltraDork
9/16/15 7:19 p.m.

In reply to cmcgregor:

Please email me, I'll be happy to discuss this further - oldeskewltoy@yahoo.com

Knurled
Knurled UltimaDork
9/16/15 7:44 p.m.

Wow, what's up with that shelf right before the guide?

oldeskewltoy
oldeskewltoy UltraDork
9/17/15 11:33 a.m.
Knurled wrote: Wow, what's up with that shelf right before the guide?

assuming you mean the unfinished exhaust bowl?? red dotted line?

That was just part of what allowed me to find an 11% gain in volume @ .350" lift.

The bowl to port work didn't hurt....

oldeskewltoy
oldeskewltoy UltraDork
9/17/15 12:16 p.m.
oldeskewltoy wrote: The bowl to port work didn't hurt....

a bit less drama...

oldeskewltoy
oldeskewltoy UltraDork
10/14/15 10:20 a.m.

oldeskewltoy
oldeskewltoy UltraDork
11/19/15 4:42 p.m.

removing some nasty bits from an SR20VE combustion chamber

oldeskewltoy
oldeskewltoy UltraDork
11/22/15 2:33 p.m.

Working the SR20VE intake short radius, bowl, and port

oldeskewltoy
oldeskewltoy UltraDork
11/25/15 4:46 p.m.

and the VE's exhaust side....

oldeskewltoy
oldeskewltoy UltraDork
12/31/15 12:11 p.m.

new client.... something called an NB....

and a bit closer view of that port.....

oldeskewltoy
oldeskewltoy UltraDork
1/6/16 7:10 p.m.
oldeskewltoy wrote: something called an NB....

More Miata.....

oldeskewltoy
oldeskewltoy UltraDork
1/25/16 6:18 p.m.

The Miata head just about finished... waiting to get 3 angle...

oldeskewltoy
oldeskewltoy UltraDork
3/29/16 10:22 a.m.

resurrected.....

Opti
Opti HalfDork
3/29/16 1:11 p.m.

It looke there was a substanstial amount of volume added to the ports on the last picture showed with the molds.

I say this because most of the domestic 2 valve heads people worry about keep the runners small and efficient and not unnecesarily large, which can show good flow numbers but bad power.

Do you ahve any info on runner volume before and after and how the engine it went on made power?

oldeskewltoy
oldeskewltoy UltraDork
3/29/16 6:15 p.m.
Opti wrote: It looke there was a substanstial amount of volume added to the ports on the last picture showed with the molds. I say this because most of the domestic 2 valve heads people worry about keep the runners small and efficient and not unnecesarily large, which can show good flow numbers but bad power. Do you ahve any info on runner volume before and after and how the engine it went on made power?

This???

oldeskewltoy wrote:
oldeskewltoy wrote: The bowl to port work didn't hurt....
a bit less drama...

Unported Exhaust: .050 - 32.45 .100 - 65.52 .150 - 90.95 .200 - 110.12 .250 - 122.80 .300 - 130.25 .350 - 135.48

Ported exhaust: .050 - 34.98 .100 - 65.03 .150 - 93.67 .200 - 113.32 .250 - 131.88 .300 - 142.53 .350 - 150.92

the intake @ .350" is @ 197.8cfm, while the exhaust is now @ 150.9, the exhaust to intake flow ratio is now a tick over 75% at peak lift, and over the lift range the exhaust to intake ratio is now about 71.5% (was 61% stock). This head's owner has not told me if the engine is back together.

Not a huge change at the outlet 33.6mm to 34.6mm. What I have done is to change the internal shape from a "Y", to more of a "V". This change allows for smoother blending/less turbulance as the exhaust leaves each valve.

As to the effectiveness of the exhaust re-taper. the only dyno I have with a mostly* stock engine shows substantial performance increases.

    • Skippy's engine is 10.7 to one 4AGE running stock cams, and she plants 120whp and 109#/ft at the wheels. Those numbers related to about 135crank hp and about 120crank #/ft. Stock 4AGE plants 112hp and 100#/ft at the crank. So with a 1.2 point compression bump, I'm making 20% more hp, and torque.

Here is port work similar to Skippy's...

Opti
Opti HalfDork
3/29/16 6:32 p.m.

I guess its the picture, but it looks like a lot of material was removed at the taper, but in the second example it doesnt seem as extreme.

Thats a heck of a gain on an otherwise stock engine.

oldeskewltoy
oldeskewltoy UltraDork
3/29/16 6:38 p.m.
Opti wrote: Thats a heck of a gain on an otherwise stock engine.

It also produce a flat torque "curve"...

Here is my exhaust work on a 2 valve head....

oldeskewltoy
oldeskewltoy UltraDork
3/31/16 10:47 a.m.
Opti wrote: It looke there was a substanstial amount of volume added to the ports on the last picture showed with the molds. I say this because most of the domestic 2 valve heads people worry about keep the runners small and efficient and not unnecesarily large, which can show good flow numbers but bad power.

Velocity is nearly as important as volume......

A few interesting things on exhaust..... 1) The 2 molds are for the same engine, but different heads. The one you commented on is a 20V 4AGE 1.6, the other casting is from the 16V version. The 20V outlet is 33.6mm (+ or -), where as the 16V outlet is 29-30mm. The 16V uses 25.5mm valves, the 20V uses 26mm valvezs So with the Toyota, the valves got a tiny bit larger, yet the port grew quite a bit more.

Now as a different POV... Nissans SR20 begin with 30mm exhaust valves and a "small" port, and by the time the VE was produced the valves shrunk 1mm, yet the port grew rather substantially.

Pics of 4AGE exhaust ports 16V and 20V

oldeskewltoy
oldeskewltoy UltraDork
4/27/16 7:45 p.m.
oldeskewltoy wrote: More Miata.....

+17hp, +15#/ft - new engine now makes old engines peak torque or more for over 3000 rpm!

oldeskewltoy
oldeskewltoy UltraDork
6/13/16 12:47 p.m.

oldeskewltoy
oldeskewltoy UltraDork
6/21/16 2:15 p.m.
oldeskewltoy wrote:
from another forum said: It will be interesting to see the before and after flow-rate comparisons.
OST said: and the results.... (before) exhaust: .050" - 29.8 cfm .100" - 62.4 .150" - 95.8 .200" - 112.2 .250" - 118.3 .300" - 121.3 .350" - 121.8 Intake: .050" - 39.4 .100" - 79.8 .150" - 118.8 .200" - 150.2 .250" - 171.9 .300" - 177.8 .350" - 180.2

and now with porting, same valves, old valve job (further improvement likely with fresh 3 angle)

Exhaust: .050" - 30.4cfm .100" - 64.4 .150" - 96.5 .200" - 114.3 .250" - 125.5 .300" - 129.3 .350" - 132.0

Intake: .050" - 39.4cfm .100" - 80.0 .150" - 122.2 .200" - 156.7 .250" - 182.2 .300" - 197.3 .350" - 204.0

.300" = 7.62mm, or just a tiny bit more lift then early stock cams(7.5mm). .350" = 8.89", or nearly 9mm.

So.... flowing through the stock ports I gain 10cfm@ .350" lift on the exhaust side, and I gained nearly 24 cfm on the intake side.

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