Stage 2 exhaust ports

Any real world experience with taking the d port on the exhaust side to to full round port increasing the size substantially?..I hear on large cubic inch engines it does work however the flow bench says different ..
The more and more I think size matters more than flow especially on the exhaust size

 

Here you go, I might have the only back to back test done on the same, same bench, same cylinder test.

Now my TE2 heads were cnc ported by Scott Brown. B4 they even go bolted on I drove to pick my bottom end up from Mike Phillips. He had his best hand ported set of TE2 heads there and surprised me with this test........he knew I was making a round trip to get the heads then the short block. My heads the exhaust is basically round, Mike's is still d shaped.

I believe Mike had this setup on a 4.350 bore.....don't know if a bigger bore might help.
My heads have 2.25/1.75 11/32 valves......not sure but I think Mike's had the same size valve.

Now I do know these heads can go bigger than what mine are, I ve seen flow sheets where TE2 go ove 400 on the intake side.....but don't recall what the exhaust numbers were on those heads.

* is where Mike's head maxed out at .620 lift then actually fell off.
My head ran into seal to retainer contact at just over .730 so as assembled i couldn't run .800

So the numbers don't show a massive difference........but his hand job was alot alot more than Scott's cnc job was.

I'm sure there is more in these heads but can't say how much.

What i don't have is velocity numbers from either head

 

Don’t get into racing flowbenches. It’s not everything. One of my engines has heads that don’t have the greatest numbers,but it makes 772/710 on 92 octane.
My heavily modified Stage2 heads still have the D-shape. Those made 865HP with 505”.

 

Mine are round (-ish). I've never had my heads on a flow bench.

 

I still call mine D-ish

 

You can also make gains with the correct header,built for your engine,not a general application. Step or multi-steps and a merge collector bs a generic collector.
This collector might look goofy,but it gained plenty of HP.

 

Here are the recent numbers from my TA Stg 2 TE, hand ported heads. Hope you can read them. The graph wouldn't load.

 

Always found this interesting ..now does this relate to our Buicks with tiny ports on big engines ?

 

BES engines share the same philosophy on CFM

 

I was told by a serious engine builder back in the day that the floor in the exhaust port is not very critical and there is little to be gained if any by lowering it. All the air is being pushed up and out.

The same guy also told me CFM flow is bragging point but port velocity is just as important. There comes a point where the port is too big and the air speed slows down and power is actually lost.

Also many folks look at the flow number at the top of the chart. Its another good brag but any flow number above the actual valve lift number is meaningless for that particular build. Ie- flowing 340 at .850 lift when the cam only nets .560 valve lift.

 

Fairly similar approach to my heads. Buick heads lack volume / cubic inch, so on a typical race build you won't make a Buick head "too big" in my opinion.

 

Yes I agree with that Gary ..just need to figure out how to make my junk work lol..bbf and BBC have it too good

 

Two intake ports which one is better
Port A Port B
.200 158. .200 160
.300 225. .300 233
.400 288 .400 312
.500 336. .500 350
.550 348. .550 361
.600 372. .600 350
.700 380. .700 noisy fluctuate 350-370
Running engine .700 plus roller port A 2.26 valve port B 2.22 valve same CSA etc

 

I would not go less than 2.250 on Buick race engine. Especially with a bigger bore on a Tomahawk.

Years back John Zerucha worked on a scrap Stage 2 heads with different valve sizes and throat percentages. His findings showed definite improvement with a larger intake and more percentage than the conservative number he used prior. The car backed up the findings on his timeslip.

I have a spread sheet with his sizes and percentages somewhere. He ended up matching the flow bench results of some of the bigger names porting Buick heads at the time.

 

I provided Keith and Duane Diabo with a scrap Stage 2 SE head years ago for R&D also. Some of what Duane learned went against conventional wisdom, and his port work development on that head ended up in both mine and Ken Montour’s 530’s Stage 2 SE heads. Heads have always been an issue making big power with Buicks, as we all know. And it isn’t about just peak flow numbers either.

 

They always say "can't have too much intake valve" whoever they are lol...mine were cut to 2.22 for the 4.35 bore at the time ..I always felt my 2 464 engines were over achievers because of the heads

 

Gary you know if he tried a 2.30 valve ?

 

Cone engineering is the go to for the day guy for merge collectors

 

My 487 cid with stage 4s 2.300 intake 1.80exh
Exhaust still stock shape.
Turn it 7500 with no issues
7200 it made 834 hp 681Tq at 5600 & still going
271/277 cam

 

Thats a strong exhaust side, but I bet the bigger 1.8 valve helps out there