Additional port work (finally completed)

[fastblackracing]

Correct. Thats why our engines probably for 95% here make peak power under 6000.
The presence of turbo boost can extend the usable range by increasing cylinder fill but peak is generally under 6k.
Optimized cam profiles and port efficiency can help push that up slightly.

Change the valve size in that program and watch the rpm range change with it.

 

[fastblackracing]

Makes it sound like i cant just send my heads to any machine shop!

It would be smart to use a shop that is well versed in our Turbo Regals. There are several out there that do good cylinder head work.

 

[Wahoo]

What are your goals?

I have to refresh my motor so the heads will be off, figured i might get them ported/polished.

To me although im unexperienced, id perfer form them to only need to he done once to make them the best they can be. But money is the limiting factor.

 

[Mike T]

The question of cc's was brought up. Some of the cc's were recovered by the use of different style valves. The photos below illustrate how different the valves are from stock units. In all of the reference pictures below the three coins were in for every shot.

The intake valves are larger than stock @ 1.77

 

[Wahoo]

Seems like its not worth going to a valve thats only that much bigger, but i dont know how much of an improvement that slightly bigger valve is.

 

[TURBOTIMMER]

You'll probably get different opinions on the valves. For the heads I'm currently working on, my machine shop recommended replacing my valves because of the style of keepers the stock ones require, so I bought new stainless 1.77/1.50 Ferrea valves on eBay. I'm basically trying to copy the heads on my rosewood car which were hand ported by Weber Racing way back in the 90s.
The others on this post have way more equipment, experience, and knowledge than I do when it comes to flow rates, etc. What I have is a die grinder, some carbide burrs, and a little common sense. Most of my work involved is in the throat area and the valve bosses. When you remove the valves, you'll see why.

 

[Mike T]

Seems like its not worth going to a valve thats only that much bigger, but i dont know how much of an improvement that slightly bigger valve is.

Your right.....just going to a little bigger valve won't make much of a difference. What does make a difference is when you do a lot of little things and the cumulative effects begin to add up.

I blew the stock head gaskets on this motor about 15 years back and while it was apart I cleaned up the exhaust ports, reworked the throat areas just a little and had a 3 angle valve job done along with better springs. These few changes made a difference that I could feel in the car.

Each time the motor is apart I do a little something different mostly because I enjoy it. I can honestly say that it has made more power every time.

There is a whole lot of basic stuff in this tread and it probably bores the heck out of most guys but I've also thrown in a couple things trying to get a little feedback and opinions from those that have "been there and done that".

I love looking at the details. The dish in the intake valve is about 2.8 cc and the exhaust is .5 cc.

 

[Mike T]

Another example of something small that will help... and I apologize to you guys that already know this kind of stuff.
A good 3 angle valve job and blending the edge of the last cut into the throat area will help flow at low lift.

The area from the pointer inward toward the guide could use a little blending. Basically just rolling the last sharp edge into the throat . This will get a new valve job with a little wider seat (was never satisfied with how narrow the 45 was).

The edge that I'm pointing to will get a small 30 degree back cut. This will get air flowing better right of the seat. Probably wouldn't make much difference at or beyond .300 lift.

This is from the intake side @ .050 lift and I think you can see how if the two areas were corrected how it would add up to better flow sooner.

The exhaust side needs a little more attention. Still not sure how far I want to cut the guide back.

 

[TURBOELKY]

I'll post those flow numbers up when I get home of the champion heads, a hand ported head and a stock head etc.

 

[Mike T]

For those interested in the differences between the stock type valley gasket and the 1200's.

The head is rough ported for the stock type gasket and you can see from the over hang that there is not a huge difference. Note that port to the far left appears to be slightly larger than the other two.....well that's because it is. For some reason Felpro made that port .025 wider on both sides of the gasket.
My fix will be to make them all this size and use the smaller diameter template for the intake manifold.

1200 over the valley type

12oo over valley type on the "big hole"

 

[bison]

Correct. Thats why our engines probably for 95% here make peak power under 6000.
The presence of turbo boost can extend the usable range by increasing cylinder fill but peak is generally under 6k.
Optimized cam profiles and port efficiency can help push that up slightly.

Change the valve size in that program and watch the rpm range change with it.

I disagree that the head flow is the reason why most make peak power under 6000. The biggest reason is because of turbo limitations and restrictions in the combination that cause the turbo to fall shorter than it should. The choke flow point of the turbine and its housing will usually occur at low rpm due to the mass flow the engine is moving. So that's the rpm range the max effort turbo limiting combo is pigeon holed into. Like trying to fart through a mixing straw. The overlap has to decrease and the CR increase once exhaust pressure starts running away or power will go backwards if increasing rpm. Tall gearing, on point converters, and narrower power bands than an NA engine because of it or you will have a slow car.


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[TURBOELKY]

I'm going to post up flow numbers in a new post. I don't want to pollute your thread with controversy lol.

 

[Mike T]

I'm going to post up flow numbers in a new post. I don't want to pollute your thread with controversy lol.

I just checked your thread out and thank you for taking the time to do the testing. I would have had no problem with it being inserted here but I think it's the start of a great thread that should stand alone for others to see. Should be interesting to see the what everyone thinks.

 

[Mike T]

I disagree that the head flow is the reason why most make peak power under 6000. The biggest reason is because of turbo limitations and restrictions in the combination that cause the turbo to fall shorter than it should. The choke flow point of the turbine and its housing will usually occur at low rpm due to the mass flow the engine is moving. So that's the rpm range the max effort turbo limiting combo is pigeon holed into. Like trying to fart through a mixing straw. The overlap has to decrease and the CR increase once exhaust pressure starts running away or power will go backwards if increasing rpm. Tall gearing, on point converters, and narrower power bands than an NA engine because of it or you will have a slow car.


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Bison I have no doubt that you correct in what you are saying but do you think that the air velocity may also begin to be a problem? I'm still learning like a lot of guys and quite honestly the mach factor is something new to me. I have read up on it a fair amount and it does seem to be a consideration.

 

[bison]

Bison I have no doubt that you correct in what you are saying but do you think that the air velocity may also begin to be a problem? I'm still learning like a lot of guys and quite honestly the mach factor is something new to me. I have read up on it a fair amount and it does seem to be a consideration.

In theory the air speed should be a problem based on the engine speed and displacement but with the performance I've seen with complete garbage heads it says otherwise. Garbage iron heads trapping 145mph at 3400lbs. Way above the norm. There's only a certain amount of air you can get in the cylinder. The flow is either reversed (back flow due to reversion, none, or positive into the cylinder. There's several degrees of crankshaft rotation that is lost fill time due to back flow on most turbo engines. Efficient NA engines will be just the opposite and may actually lose part of the incoming charge out the exhaust valve due to superior scavenging. In the turbocharged engine it's just like chopping off intake duration under higher drive pressure vs manifold pressure conditions but even worse than that for cylinder fill since inert gas becomes a large % of the intake stroke. Not only is the cylinder not filling its polluted with a bunch of inert crap taking up valuable space. The piston has to travel far enough down the bore to equalize the pressure differential and beyond that it will begin filling. Looking at an efficient NA engine this won't happen. The camshaft, head flow, displacement, bore size, deck height, and CR can create much more predictable air flow into the cylinder at a given rpm on an NA engine. Basically the turbo just buffering both ends of the spectrum. Very positive till drive pressure to manifold pressure ratios get unfavorable. If the manifold pressure and drive pressure remain close to 1:1 more of the theories that apply to NA engines apply. Also why that same engine will show great power at low boost and the owner will be posting all over about it but will suck once the drive pressure starts taking off and the back flow murders the cylinder fill. You're left with a high pressure inert gas at tdc just waiting to punch the new intake charge right in the face as the valve begins to open. Going back to the partial drive pressure discussion in the intercooler thread you can see clearly why reducing this pressure relative to manifold pressure will always net an increase in mass flow if the charge temp improves, is linear, or even increase to a certain extent. With all this real world it seems that turbo engines do like larger port volumes than would be considered normal for the engine size and displacement. Possibly because of the dilution and delay of cylinder fill at low intake valve lift but that's a theory in itself


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[Mike T]

Thanks for the detailed explanation. My car behaved a little like you are describing. It would pull really hard to about 5200 and then gently taper off. The boost would continue to creep up but the pull was not proportionate and I'm certain that it was not valve float.

This time around It's getting a 210/210 roller and a different exhaust system which may help with this.

 

[INEEDAGN]

Current trends in cylinder head porting try to limit the air speed in the intake port speed to .5-.55 mach or slightly under which is 563 feet per second.We are talking flow bench numbers here.
This is important because as the air speed goes up the air can no longer follow the turns in the port near the valve and the air goes turbulent
causing the max flow capability to drop. [ Thanks for the link jerryl

One of the tips in one of my Smokey Yunick books, is that if you have to deal with a choke point such as pushrod clearance, to increase the cross sectional area AFTER the pinch and leading up to the turn. This expansion slows the velocity and helps the airflow make it around the short side radius instead of slamming into the roof and disrupting flow. It supposedly works on any design but really helps if you have a pinch point.

 

[Mike T]

Set up outside of the shop this morning to avoid getting dust everywhere. Ended up putting in a 10 hour day on the exhaust side and still have a lot of blending to do.

 

[Mike T]

 

[TURBOTIMMER]

Looks really good, Mike. I started on the exhaust ports on mine, but I'm gonna fill my egr ports with aluminum before I go any further.