Custom inlet manifold - Suggestions please...

[Ben Wilson]

I stuffed it

Part of this project is learning to use my henrob welder and I put to much heat into the materiel trying for nice fillets and managed to warp it..

I still think the ideal has merit, I'm in the middle of building up blocks and jigs to hold it all in place while I weld it this time...

Unfortunately, I don't think devcon could handle the heat of welding the plenum on - I might try it on a bit of scrap today and see what happens. I'll definately be wearing a respirator while I do that.

[jmac]

Dave's right on this - it doesn't need to be a protruding bellmouth, you can get maximal flow without them (though it will work pretty well, it's not necessary so you can save some time/$$)

There is a formula (and I don't have it here) that's been brought up on

http://www.theoldone.com

forums (which kick ass) I think R/D = 0.5 but I'm not sure which radius and diameter is inolved.

There's a post about it in the ASK TOO section, where he also provides scans of some of the adaptors they use for flow bench work where they need an optimally flowing inlet of some particular dimension

Actually I'd strongly urge visiting the site in general to get insight as to what works and what doesn't (It's one of the best signal:noise ratios you'd ever find on the net)

Another thing they push is the practice of measuring the port floor and roof from the inlet valves, and actually shaping the mouth of the runners to that the runner lengths (floor vs roof) are equal. Generally the roof is longer. It apparently makes a big difference in flow quality (lowest disruption/turbulence, and generally more uniform flow throughout the port, it's all relative)

John McKenzie

[Nero]

John TOO/ENDYN have some unusual theories that at times are not supported by other more educated luminaries such as on eng-tips etc. I agree that there are some good things about the site, but I would prefer to see more emperical evidence of the benefits of their theories.

[Matt]

Larry Widmer/TOO is somewhat of a crack-pot....

[jmac]

out of interest, what stuff in particular are you after more evidence on?

I'm not saying he's perfect, but I can personally attest that he's not the only source I've been exposed to the port wall length matching theories.

He's also (by a country mile) not exactly alone in the runner entry shaping stuff.

How about running a motor with somewhere in the neighbourhood of 11:1 compression and >20psi boost on pump fuel?

One thing that did impress was when someone had a problem with an oil seep from where an aux breather pipe was welded into the block. Without hesitation or even being yet asked to, he stepped up and said he'd pay whatever costs the guy had, to take it to a workshop and get the motor pulled, packaged and shipped back, he'd repair it and then freight it back and pay for it's reinstallation.

And rightly so, but I've never heard of anyone ever doin that - they normally only do the work and offer a warranty in the first place if the customer removes and ships it (unless they fitted it)

What about the carbon fibre inlet Endyn designed (but being carbon fibre obviously they didn't build). I recall on a honda site one of the first ones was put on a highly developed turbo honda, with what was (up until then) the best option ( a heavily modded factory or aftermarket I forget) and it made something like 10% gain, and it also pick it up across the rev range and in fact had a wider power band. Hardly bloody cheap (costs more than I would spend on a whole car) but it did 'produce'

He was called a crack pot about 20 years ago for his 'theories' about swirl and flow quality, over pure cfm, try and find anyone who doubts it now.

It's ironic, but another one of the things he talks about is transient response, and how two motors with similar dyno hp readings can produce differing 1/4 performance due to it. A long time ago when I was just getting into turbo holdens, (and the 'technologically overwhelming garret drawthrough kits) there was a couple of manifolds available. I ended up tracking down a stage (strata) 5 manifold. At the time, the turbo specialist who sold it to me, was reluctant to do so as it showed absolutely zero hp increase on the dyno. But I was adamant,because at the time, a person I knew through a friend of a friend had one on an LJ. With the swap from the st 1 inlet to the st 5m and no other changes and no alteration to the wastegate (so identical boost levels) the car ran close to a whole second quicker.

At the time, I knew that he wasn't a bullshit artist, and I couldn't figure out how the hell the two seemingly mutually exclusive claims could be true. It wasn't until years later that I was introduced to this, and it finally explained things. Strangely the manifold was larger so you'd think it would drop velocity a bit, maybe it needed to be slowed down a touch, maybe it was some weird quirk of the extra volume and it being a drawthrough (and a manual)

having said all that, I'd welcome any feedback, as I don't think anything is 'etched in stone' either. I'd also appreciate a url for the site you mention (unless its eng-tips dot com ) as I'm a 'junkie' for any technical exchanges.

John McKenzie

[Nero]

it is eng-tips.com and there are some high powered people who occasionally grace the from (e.g. the senior power train engineer for jaguar etc) having said this the forum varies a bit in quality ATM and you are supposed to be a 'qualified engineer' to post.
My 'critical' comment should be more viewed as a sceptical comment. I have no doubt that the people there are successful at doing what they do and are also successful in the business too. However some of the theory that is expoused e.g. the swirl is not new now and was not new then with Chev in particular having produced a head that predated his theories by a few years. But my sceptical nature wants more information and independant testing. The stated swirl was measured how? Is it the correct amount of swirl for the droplet size/suspension ratio of the fuel with the coumbustion chambers used and how did they make changes/measure swirl etc?
I have had a short conversation with a Mr Duckworth re barrel throttles/ports (he has his masters thesis posted somewhere on the net) and some of the thoughts I'd had re endyn were not matched by what I was told or the answers to the question I asked at the time of TOO/Endyn.
The port measurement you mention is a fine theory and is largely true however it is a tiny advantage if done correctly that is difficult to see is worthwhile.
As far as his offer of the work...no issue it is generous. In fairness it does support his business to develop a reputation as helpful and also in fairness I know some businesses that are very helpfull in Melb (though I doubt that they would pay for shipping!)
The transient response is interesting I have a book on my shelf by guy croft that goes a bit into transient response tuning...again its not new (lets face it nothing is) but I do like the focus on this testing and not the woftam of steady state dyno figures.
So in short I do not think that TOO/ENDYN are crap, but they are not pushing any new boundaries in tuning theories/techniques. What I do applaud is their willingness to publish infoprmation on the net as they do and to support the market they are servicing.

[jmac]

I don't think he ever claimed to invent swirl. He was one of the first people outside of manufacturers to look at stuff like that (with any seriousness) for performance though.

I'm buggered if I know how he measured swirl, but from memory he indicated it was work in aeronautics that either gave him access to the computing power or software (remember we are talking about something that happened well over 20 yrs ago)

He's big on laminar flow testing (which I think are covered on how stuff works?) basically trying to achieve aws consistent a flow as possible in any section of the port. If you look at what's available for cleveland 4v heads these days, tongues to fill in the port floors especially, they end up flowing as much or more, but even at the same flow produce more power and a wider power band. He was doing stuff like that in the 70s for prostock as far as I know. He does show pics of drastically filled in ford ports, I'm fairly certain they are 4v cleveland by the look but am not 100 percent.


Could you email me any info you have on rotary valve engines? I do recall a website some time back that I visited. I haven't heard a hell of a lot about them lately. Believe it or not the main place I've heard about them (but not seen in the flesh) is their use on (drumroll) holden grey motors! They certainly made sensational power for the limitations of that engine, and for that time in history. I think I've heard about them in go kart racing, but only as a passing comment - anyone?

jmac@alphalink.com.au

[Ben Wilson]

TOO has always managed to bug me for some reason, which in my experience usually means he has a good idea what he is on about - I don't know why good engine builders/tuners always rub me the wrong way....

As for my manifold, take 3 of the inlet trumpets is coming along, I seem to have been able to get around the distortion problems for the moment, I think I might just leave the little 'corners' as they are, just round the edges of them with a die grinder.

No matter what I do, it's got to be better than the factory one...



Note the careful finish Toyota put on the edges of the factory runner....

[Billzilla]

Quick tip, Ben - Most of the air going into the trumpets comes in sideways, not straight in.
You need as much clear area beside the end of the trumpet as well if possible.
I quite agree that pretty much anything would be better than the stock manifold.

[Ben Wilson]

I was working on a variation of that sort of concept, hopefully, by merging the edges of the trumpet into the plenum, I will get a sort of 'infinate trumpet' effect..

[Ben Wilson]

Got it worked out - With some careful cutting and hammering I managed to get the tubes to merge nicely with the trumpets.





It even fits in the engine bay...

[Billzilla]

VERY neat indeed.
What's the rest of the plenum going to look like?

[buzz]

neat. how is the henrob going?

[Ben Wilson]

Bill - Rest of the plenum? It's basically like the photo at the top of the thread..

buzz - Getting there, I'm spending a lot less time searing at it than I used to. I have sucessfully welded aluminium with it (but it wasn't pretty....)

[hamish]

Ben, what sort of lens & flux did you use for the Ally?