Cylinder Head Flow Benches (recent tuning threads)

[Workshop]

Well I'm just starting out porting my own heads so anything I can learn from you guys will be great. I'm just waiting for your porting book to hit the shops as well David but at the moment I'm looking at building the FD flow bench.
Cheers

[David Vizard]

Workshop said:

Well I'm just starting out porting my own heads so anything I can learn from you guys will be great. I'm just waiting for your porting book to hit the shops as well David but at the moment I'm looking at building the FD flow bench.
Cheers

check out my post in the Stan Wiess interview before you spend time building that bench! Fail to do that and you will spend a lot more time and money building a less capable bench.
DV

[J381]

Resurrecting this thread.

Can anyone recommend someone in the UK to do a proper job on my cylinder head (3SGTE - MR2 turbo)?
Rebuilding the engine with a large GTX series turbo, so naturally I want the head done.

Cheers.

[Pumaracing]

To be honest most places are so useless at cylinder head work that it's unlikely anyone on here is going to recommend someone else with a clear conscience. Standards can vary from a quick pass with a flapwheel to polish the ports which achieves nothing right the way up to the best possible port shape modification and seat cutting profile. Trouble is the cost is usually not that much different for either standard of work.

[stevieturbo]

J381 said:

Resurrecting this thread.

Can anyone recommend someone in the UK to do a proper job on my cylinder head (3SGTE - MR2 turbo)?
Rebuilding the engine with a large GTX series turbo, so naturally I want the head done.

Cheers.

I'd be more concerned about the block than the head.

I think Fensport use JEM racing engines ?

Or maybe try that CNC heads place ?

[226bhp]

The guy at Deltaparts has considerable flowbench experience with this head, cam spec and it's brothers, from what I learned it isn't great, but ultimately it depends on what you want and your budget.

[Kokkolanpoika]

Every head porter can make good CFM readings´s from bench, but those readings are not real life power. I´m not a flowbench fan. I have seen to many bad ported head´s witch make way to mutch power vs bench readings.. You cannot´t quarantee that last CFM`s give the last horses.
Example some toyota starlet 5k engine (1.6l) make 190hp with fully bench worked head´s. They make copuple of heads´s and compared witch one is better. But last one they make without bench, they raise port volume mutch over optimal and engine make 204hp and also it will make approx 0.3bar vacuum. So throttle bodies will now resist flow also. They think that 215hp would be quite optimal if change bodies to 45mm. Now it will run 42mm.. Inlet valve is 41mm diameter, throat +90-92%.Engine will run +9000rpm.
https://www.youtube.com/watch?v=22l1-JKpGDQ

Some head porter use ~92 throat´s.. Why there is a rule that 85-88% would be better.? You can get all valve area to use if use bigger throat. Also you can use smaller valve if want? But´t as i say, every head will need it´s own trick´s..

http://www.ebay.co.uk/itm/Rover-V8-Head-Porting-Mi...

[PeterBurgess]

Interesting observation on flow bench dependency by some tuners. We too have found oversize ports work well in TR4 heads. Some factory ones had 'ideal' size ports whilst others had 'way' oversize inlet ports according to the number crunchers. The big ports make big power at high rpms and big torque at low rpms contra to that indicated by the mathematical approach.
Flow benches are a good tool but not the be all and end all of power development. One also needs power testing capabilities and best of all...championship wins to verify the work. If you consistently beat the opposition it doesn't matter how many cfm they have

Peter

[Mr2Mike]

This guy has an interesting porting methodology for bike engines.

[anonymous-user]

Mr2Mike said:

This guy has an interesting porting methodology for bike engines.

I've no idea why american "Tuners" (and i use that word sparingly) feel the need to state the bleeding obvious, but wrap it up in WooWoo and myth as if they are some sort of messiah?

B*llSh*t of the highest order!

[Pumaracing]

Mr2Mike said:

This guy has an interesting porting methodology for bike engines.

That old b0ll0cks has been around on the web for years. I wouldn't go quite so far as to call it interesting. It's typical American hyperbole with very little data wrapped up in a sh!t load of exaggeration, advertising claims and pretty coloured type faces. There are no actual measurements of port diameter versus valve size before and after or how this compares to other engines, say non-bike ones.

It's very simple in essence. If a port is too big then making it smaller will help but if it's too small then it MUST be enlarged. Every engine is different. The 1600 Ford CVH has 42 mm inlet valves and 30 mm ports. The Ford Pinto engine has 42 mm inlet valves and 36 mm ports. One is too small, the other too big. Near as dammit they both flow the same as stock because it's the port bends that limit the flow not the port size between the manifold face and where the port starts to bend. Once the port bends have been rectified the CVH ports need opening up a lot and the Pinto ones don't need to be touched. In fact filling in the redundant parts of the Pinto ports as Vizard did with his "Apple" heads 40 years ago helps flow. Do the same on a CVH as this American idiot claims and you'd kill it even further.

The hard bit is knowing when the port is too big or too small relative to its valve to start with. That depends on a host of factors including the port downdraft angle, the straightness of the port, chamber shrouding and very importantly the state of tune of the engine - compression ratio, cam duration, induction and exhaust system etc.

For some of this the flowbench can help but in fact basic flow theory can get you there just as well if you understand it properly. However there is another higher level of understanding which takes you past flowbench work which determines the port area and gas speeds required to generate a particular amount of horsepower per cylinder. Once you're up into that level of engine development you find that flowbench numbers and bhp ones don't always correlate any more like they used to in less highly modified engines. You can do things with the ports that don't show up as more flow but do show up as more power.

As to the hoary old myth that big ports = poor torque and vice versa. There's a grain of truth buried in that but the main straight part of the port between the manifold face and the shortside bend plays almost no part in this. If it did then the CVH would theoretically be a stump pulling tractor engine and the Pinto with over 40% more port area for the same flow wouldn't pull the skin off a rice pudding. In fact their torque characteristics as stock are almost identical. The bits of the port shape and size that actually matter have been discussed in previous threads for anyone smart enough to tease them out.

[Pumaracing]

PeterBurgess said:

Interesting observation on flow bench dependency by some tuners. We too have found oversize ports work well in TR4 heads. Some factory ones had 'ideal' size ports whilst others had 'way' oversize inlet ports according to the number crunchers. The big ports make big power at high rpms and big torque at low rpms contra to that indicated by the mathematical approach.
Flow benches are a good tool but not the be all and end all of power development. One also needs power testing capabilities and best of all...championship wins to verify the work. If you consistently beat the opposition it doesn't matter how many cfm they have

Peter

There is no such thing as an incorrect mathematical approach if the maths actually work. All you are actually saying is the maths you think, or thought, were supposed to work actually don't appear to in practice. That's only because you didn't know the right equations for all situations, or more properly because you were only applying some very simplistic rules, probably gleaned from the Superflow manual originally, which of course are not universal.

In actuality the equations that determine the maximum port sizes for best flow on the flowbench are not always the same as those that determine the optimum port sizes for bhp. The trick is knowing in which circumstances each of them apply. This leads to much more complicated equations which contain some "IF THEN ELSE" rules. If variable A is between certain limits then apply equation 1. If variable A is between other limits then apply equation 2 etc.

If all this were not actually calculable then Computational Flow Dynamics (CFD) would not be possible but in fact it's now one of the most powerful tools available for designing everything from F1 car aerodynamics to airplanes to engine ports. Sadly it is however just a tad more complex than X CFM = Y bhp, especially if ones flowbench doesn't really work properly.

[PeterBurgess]

Oh my God, and I thought my flow bench was perfect and helped me win championships all these years. Thank goodness I am not a flow bench dependent tuner, or maybe after all these years of winning championships it is still pot luck do you reckon Dave



Peter

[Pumaracing]

In the valley of the blind the one-eyed man is king.

[PeterBurgess]

And above the valley soars the Eagle and it can be heard saying, "Aquila non capit muscas"
Merry Christmas and a Happy New Year to you Dave.

Peter

[Mr2Mike]

Pumaracing said:

That old b0ll0cks has been around on the web for years. I wouldn't go quite so far as to call it interesting.

I should probably have put "interesting" in quotes.

[Pumaracing]

Kokkolanpoika said:

Example some toyota starlet 5k engine (1.6l) make 190hp with fully bench worked head´s.
They make copuple of heads´s and compared witch one is better. But last one they make without bench, they raise port volume mutch over optimal and engine make 204hp....
They think that 215hp would be quite optimal....
Inlet valve is 41mm diameter

I think someone needs to put their engine on a proper engine dyno if they think a 1.6 litre 2v per cylinder engine with 41mm inlet valves is making over 200 bhp.

[Kokkolanpoika]

Or someone has to learn to make better engines..

I do not see any reason why +200hp is not possible? If power comes around 9200rpm..

[Kokkolanpoika]

Old setup, small port heads and if remember right it has got 40mm inlet valve with this dynopull..

https://www.facebook.com/video.php?v=7644259669370...

https://www.facebook.com/media/set/?set=a.53281312...

[Pumaracing]

Kokkolanpoika said:

I do not see any reason why +200hp is not possible? If power comes around 9200rpm..

I thought we'd covered this sort of stuff quite thoroughly in the Ford Crossflow engine thread last year where the mythical 200 bhp engine didn't appear to exist and 180 bhp was the limit from a number of engine builders even using capacities up to 1.9 litres.

You seem to think this 1.6l pushrod 2v Toyota engine can match the power of the best Ford Pinto 2 litre engines with much bigger valves.

So I have to wonder what do you actually think does limit the power of a given engine or do you not have this level of knowledge yet?