ESE's works engine tuner

[husaberg]

I did spend (way too much) time reading on the subject - but as it turns out - you can only fit what there is available space for...
I picked up a barely used rad from a guy that had some bad overheating with it - whoever built it had the inlet in the top left & outlet in the bottom left side - so i figured it was short circuiting without actually cooling - I blanked off the outlet & made a new header for it making it double pass (I hope) so forcing all coolant to go down the one half & back up the other to get maximum cooling.
I then tried to concentrate on getting the best seal on the entry - whatever I'd read on entry size didn't much matter - just used what I'd got - and basing my thinking on what we had on the old bike (which worked well enough)
I think you can maybe over think a lot of this (and lots of other stuff too) a lot of the time you can look at something for a while & it's obvious whether it will work or not - main thing I think is to have a duct that has the entry well sealed - if you are scooping air - you don't want it escaping before it's gone through the rad.
All of this took a lot longer than I'd have liked - the original fairing design didn't have the space or the entry where i needed it - so had to make a new fairing - involved a lot of Glass fibre work - making new molds etc but worth the effort - I now have the rad entry I want - and also gives me a lot more space to fit different pipes - there was zero space for any different pipes with the old fairing design.

Just going back to that rad - the guy that had it made - put the inlet / outlet where it was most convenient for the rest of the bike - wrong move I'm afraid - what he should have done is think a bit harder - first - how does this system work - and next - how to adjust the rest of the bike to fall in with that - you can't let not important stuff dictate important stuff !

One thing from bradleys book was he believed the radiator would work better leaning backwards, I can't remember why?

[G Jones]

One thing from bradleys book was he believed the radiator would work better leaning backwards, I can't remember why?

I think you're correct - I spent a lot of time reading John's book - but it still came down to the "available space" - I totally hate "compromise" - but sometimes you have to - either that or scrap the project...
I have spent a lot of time reading the "Bradley Books" - I can remember him from over 40 years ago - we were both racing 125 yams at the same time...

[seattle smitty]

Air-cooled recip airplane engines have "pressure cowlings" intended to force air all the way around and through their close-fitting cooling fins. Seems to me you have the same requirement; your engine is liquid-cooled, but the radiator is air-cooled, and forcing air under pressure through the cooling fins of the radiator calls for a "pressure cowling." The pressurized air can be forced through cooling fins (of whatever kind) at a considerable angle to the airflow into the front of the cowl; think about little airplanes with opposed-four and six cylinder engines where the fins are a full ninety degrees to the air entering the cowl. No, the air doesn't blast into one side of the cylinders; instead it builds pressure and shrouds turn it a full right angle so that it is forced downward around all sides of the cylinders, under pressure, and then flows out underneath the airplane . . . and in better designs is to some extent extracted by a low-pressure area.

Peewee, with this in mind, I'm not sold on the three-part drawing you put up for discussion on P. 1406. The author is inadvertently showing two different effects because his drawings are too simplified. The bottom drawing, supposedly the "best" option of the three, does indicate that you want a non-turbulent airflow around the outside of the radiator shell, which is true enough. But my first problem with the drawing is that he doesn't carry the idea past the widest part of the radiator, when in fact you'd want to carry it as far as you can past that point (ignoring "packaging" problems for the moment). As drawn, the airflow would immediately go turbulent as it tries to re-attach when it passes the widest part of the radiator. What you'd ideally want is, via good fairings, to get the airflow to come together far enough downstream of the radiator that is creates something of a draw on the air coming out of the radiator. This is a whole lot easier to do on a rig like Jones', or a Bonneville streamliner, than on a bucket, but you do what you can.

The second of those three drawings is claimed to be not as good as the third, but why? If the author was making a point about airflow AROUND the radiator, okay. But if he was worried that some of the entry-air would not be used, and would spill out the sides (as he has drawn it), I think that's not a problem. To achieve a pressure-cowling you have to build up a head of pressure, and naturally some of the entry air will spill out. Well, so what? You want that pressure build-up, to force the air between all parts of the fins and tubes. The air-entry openings in front of airplane cowling are pretty small, but airplanes are going relatively fast, and the holes into the pressure cowls are sized for best efficiency.

I think this all is a particular problem for bikes, because with the front tire, forks and braces, maybe a fender, the airflow into, let alone out of the radiator, is going to be pretty haphazard and turbulent, the very opposite of what you'd want to get air pushed, and maybe pulled, through all those little fins and tubes. For that matter, the same problem applies to bikes with air-cooled cylinders. Some old Suzukis had what they imagined to be ram-air partial cowls around the heads. But to be ram-air, they would need air blasting directly into the front of the gizmo; how can this be with the tire and forks making the air eddy around every which way? As much as I like the look of an old-fashioned naked motorcycle, having a cowl lets you duct the air in useful ways.

TeeZee and I exchanged some PMs on this subject some time back, and he has some good ideas about it.

[teriks]

The second of those three drawings is claimed to be not as good as the third, but why? If the author was making a point about airflow AROUND the radiator, okay. But if he was worried that some of the entry-air would not be used, and would spill out the sides (as he has drawn it), I think that's not a problem. To achieve a pressure-cowling you have to build up a head of pressure, and naturally some of the entry air will spill out. Well, so what? You want that pressure build-up, to force the air between all parts of the fins and tubes. The air-entry openings in front of airplane cowling are pretty small, but airplanes are going relatively fast, and the holes into the pressure cowls are sized for best efficiency.

Most likely because the extra inlet area adds nothing but drag.
From a strict cooling point of view it wont matter though, unless you add something like a front wheel in front of that inlet, then you might want something like #2 after all.
EDIT: So basically I agree with what you said later in your post.. should learn to read to the end before replying
Glad I only have the spinning prop to worry about in front of my intakes..

[seattle smitty]

EDIT: So basically I agree with what you said later in your post.. should learn to read to the end before replying

Oh man, anybody who finds anything I say worth a comment might want to wait half an hour after I post it, because I frequently spend that long coming back and editing it so it might make sense, doh!!

[peewee]

smitty if the area behind the rad is low enough pressure then wouldnt the air have no choice but to go through the fins, rather than some of it bouncing back out around any ducting like the photos show ? thats my understanding of it anyways. maybe the inward tilted ducting creates a lower pressure behind the rad. hell i dont know.

what i do know is it wont be feasable for me to use nice fancy fairing and such. well maybe it would be possible with alot of time and thought but i was hoping to keep it somewhat simple but decently affective and thats why i originally posted the rad photo with three different scenarios. depending how much they weigh i was also thinking of a small electric fan on the back side with cowling around it like a car. this project is going to be a methanol drag racer so maybe im over thinking it but still it seems like some sort of ducting will be better than nothing at all. then again maybe no ducting is better than poorly designed ducting. in the meen time ill search the web for info

jones ill have to get some measurments but if my airbox available space is to small maybe ill be better off with no airbox at all. i havent got that far yet but ill report back when i have a better idea of the available space

while im thinking of it, does anyone know of a website with a decent gearing/rpm calculator. i have two sets of primary gears with different ratios that i can use and i wanted to compare the rpm drops through gear changes. so far most of the calculators ive found only show mph differences bewteen gears.

[Frits Overmars]

i have two sets of primary gears with different ratios that i can use and i wanted to compare the rpm drops through gear changes. so far most of the calculators ive found only show mph differences bewteen gears.

The primary ratio has nothing to do with the rpm drops through gear changes. If for example you double the primary ratio, you must halve the secondary ratio in order to reach the same speed at the same revs, but that won't change the ratio steps between the gears.

[G Jones]

jones ill have to get some measurments but if my airbox available space is to small maybe ill be better off with no airbox at all. i havent got that far yet but ill report back when i have a better idea of the available space

OK - you may need a reasonable amount of space - I'd have liked more - but if you can duct an inlet somehow - you'll increase the amount of air available - however - one of the best things about the airbox (at least from my point of view) - is that there is less of the dust & small rocks getting in the engine - completely open carbs always suck in any crap that comes close...

while im thinking of it, does anyone know of a website with a decent gearing/rpm calculator. i have two sets of primary gears with different ratios that i can use and i wanted to compare the rpm drops through gear changes. so far most of the calculators ive found only show mph differences bewteen gears.

I have a gearing / speed calculator on my website - it's set up for TZ350 & sidecar wheels - but you could download the script & code - adjust to suit what you need....

[wobbly]

Here is a simple calculator with tyre size, ratios,rpms as inputs.
With speeds and rpm drops as outputs.
Its setup with a stock TZ350, but can be changed to anything you want.

[husaberg]

smitty if the area behind the rad is low enough pressure then wouldnt the air have no choice but to go through the fins, rather than some of it bouncing back out around any ducting like the photos show ? thats my understanding of it anyways. maybe the inward tilted ducting creates a lower pressure behind the rad. hell i dont know.

what i do know is it wont be feasable for me to use nice fancy fairing and such. well maybe it would be possible with alot of time and thought but i was hoping to keep it somewhat simple but decently affective and thats why i originally posted the rad photo with three different scenarios. depending how much they weigh i was also thinking of a small electric fan on the back side with cowling around it like a car. this project is going to be a methanol drag racer so maybe im over thinking it but still it seems like some sort of ducting will be better than nothing at all. then again maybe no ducting is better than poorly designed ducting. in the meen time ill search the web for info

jones ill have to get some measurments but if my airbox available space is to small maybe ill be better off with no airbox at all. i havent got that far yet but ill report back when i have a better idea of the available space

while im thinking of it, does anyone know of a website with a decent gearing/rpm calculator. i have two sets of primary gears with different ratios that i can use and i wanted to compare the rpm drops through gear changes. so far most of the calculators ive found only show mph differences bewteen gears.

Here is a simple calculator with tyre size, ratios,rpms as inputs.
With speeds and rpm drops as outputs.
Its setup with a stock TZ350, but can be changed to anything you want.

http://www.kiwibiker.co.nz/forums/sh...post1130461984
http://www.gearingcommander.com/

This one below have nice graphs as well.

[peewee]

thnx for the help fellas. frits i thought changing the primary ratio some how made the gear spread wider even though the trans gears remain the same. guess i better do more research as i hardly know anything about this subject. am i reading this chart correct ?

if the shift point is 10,500 at each gear

1-2 would drop to about 6800 , a drop of 3,700 rpm
2-3 would drop to about 8000 , a drop of 2,500 rpm
3-4 would drop to about 8600 , a drop of 1,900 rpm
4-5 would drop to about 8700 , a drop of 1,800 rpm
5-6 would drop to about 8700 , a drop of 1,800 rpm

[peewee]

Here is a simple calculator with tyre size, ratios,rpms as inputs.
With speeds and rpm drops as outputs.
Its setup with a stock TZ350, but can be changed to anything you want.

thats a nice one and just what i was looking for. aparently theres a newer version now gearing_V12. looks pretty similar but it has stuff listed in mph also

after trying different primary ratios i see what frits was saying about the gear change rpm stays the same. so what would be the purpose or reason to have more than one primary gear set available ? im guessing if you were racing long distance and needed all five gears for alot of top speed vs a short race and only needed three gears

[husaberg]

thats a nice one and just what i was looking for. aparently theres a newer version now gearing_V12. looks pretty similar but it has stuff listed in mph also

after trying different primary ratios i see what frits was saying about the gear change rpm stays the same. so what would be the purpose or reason to have more than one primary gear set available ? im guessing if you were racing long distance and needed all five gears for alot of top speed vs a short race and only needed three gears

Its all only about gearing.. Use whatever primary gearing gets the gearbox to spin faster to lessen the load on the gearbox and clutch.
ie if you have a choice between say 3.5:1 and 3.0:1 choose 3.5:1

[lodgernz]

Its all only about gearing.. Use whatever primary gearing gets the gearbox to spin faster to lessen the load on the gearbox and clutch.
ie if you have a choice between say 3.5:1 and 3.0:1 choose 3.5:1

I think you have that back to front Husa. 3.0:1 will spin the clutch faster

[husaberg]

I think you have that back to front Husa. 3.0:1 will spin the clutch faster

Right you are......Backwards I do have it