ESE's works engine tuner

[speedpro]

while im thinking of it, anybody tried something like this ? maybe its stupid idea but could you hook one end of this cooler to the carb and put a airfilter on the other end. then use a small pump and heat exchanger. http://www.frozenboost.com/air_water...ers-p-226.html

The whole point of these is to reduce intake charge temperature that has been raised by a compressor of some sort compressing the gas.(Boyles Law) The beauty is that they are compact and can be placed in a crowded engine bay with a remote radiator to extract heat from the water. Plus they are a lot lower volume, especially when you take into account the plumbing to a front-mount intercooler, so possibly some advantage in the time to build boost.

I don't see the benefit fitting it to a normally aspirated engine, unless you refrigerate the liquid and then lower the intake temperature. I expect there would be a small gain from that but doubt it would be worth the trouble.

[speedpro]

Would it be easier and possibly less expensive in the long run to buy a Davies Craig pump and possibly the controller too?

http://daviescraig.com.au/electric-water-pumps

I've had a good look at them. Lots of good points including magnetically coupled so no seal to leak.

[husaberg]

yes I know its a water/air intercooler for a small car I suppose. wasn't sure if it could be connected directly to the carb but then you would need a pump, water, and another radiator. rather heavy system . what about a small ice box plumbed into it ? then you could have cold air but not feasible on a small bike I guess

A NA carb effectively cools the air intake due to the evaporation of fuel, A turbo or supercharger heats the intake due to the compression of the air prior to use.
TZs bike is a circuit bike a large and longer intake sticking out the side would be rather problematic on right handers.
Ice coolers are used to great effect FA of drag racer that are only used for seconds at a time.
A plenum if he goes that route again, could be cooled or at least isolated with a ceramic paint or coating. Or a refrigerant.

I've had a good look at them. Lots of good points including magnetically coupled so no seal to leak.

As is this bosch one
http://www.metricmind.com/products/bosch-pa-66-gf-30/
http://www.bosch-ibusiness.com/boaaw...3?locale=en_GB

[Haufen]

As is this bosch one
http://www.metricmind.com/products/bosch-pa-66-gf-30/
http://www.bosch-ibusiness.com/boaaw...3?locale=en_GB

That's my favourite when it comes to coolant pumps. Weight vs. size vs. current vs. coolant flow vs. price (new from 60 USD) all very good.
It is, however, slightly more sensitive to pressure drop in the coolant circuit than others. (use 2 in this case, still cheaper and lighter as other pumps).

[Magnus676]

Good evening to everyone here.
Ι read this topic for some time now,and I'm impressed-at least-with the tuner names around here
My question is about the 2 stroke drag bike I've been building lately.
I've been thinking this for the last couple of weeks and I still can't decide.What's best power curve for a drag bike?
As much power as you can get in a small rpm range and power droping out quickly,or less power with a wide usable rpm range and a lot of overrev?
And something more.Probably I'll use meth instead of racing gasoline.What should I do to my engine in order to support meth apart from increased fuel flow to..ehhm..everywhere ?Common "racing" spark plug?More piston to cylinder clearnce because of the higher compression ratio or less because of the cooler engine?
Have a good rest of the day fellas..

[Frits Overmars]

What's best power curve for a drag bike? As much power as you can get in a small rpm range and power droping out quickly, or less power with a wide usable rpm range and a lot of overrev?

Hi Magnus, the problem with answering your question is that words like much, small, quickly, wide, usable and 'a lot' have no numerical meaning.
I developed a numerical way to answer questions like these, called Power Range. You can find its description here: http://www.kiwibiker.co.nz/forums/sh...post1130525788

Which power range is best for a drag bike, largely depends on the amount of power itself, and on the clutch and gearbox.
For example, a Top Fuel car with thousands of HP needs a damn good clutch and only two gears; a 50 cc drag bike doing a quarter mile will need all of its six gears.
You will have to build your own experience regarding what your bike needs. My experience with drag racing is limited, so I can only give you a rough indication:
its necessary range may be smaller than the 1,4 that you would need for road racing.

[peewee]

As is this bosch one
http://www.metricmind.com/products/bosch-pa-66-gf-30/
http://www.bosch-ibusiness.com/boaaw...3?locale=en_GB

that looks more compact than the other bosch posted previously but I think its l/m output might be less. I wonder if the pump wobbly posted isn't the best so far ? although it doesn't give any size dimensions or weight.

[peewee]

Hi Magnus, the problem with answering your question is that words like much, small, quickly, wide, usable and 'a lot' have no numerical meaning.
I developed a numerical way to answer questions like these, called Power Range. You can find its description here: http://www.kiwibiker.co.nz/forums/sh...post1130525788

Which power range is best for a drag bike, largely depends on the amount of power itself, and on the clutch and gearbox.
For example, a Top Fuel car with thousands of HP needs a damn good clutch and only two gears; a 50 cc drag bike doing a quarter mile will need all of its six gears.
.

frits is exactly right about the clutch and gearbox. im only a amateur drag racer but I learned long time ago that if gear spacing is to wide and powerband to narrow , the bike will be a failure.

something else important is a transmission that can change gears up with no power interruption. I made a video in the sand to visually see the results of a standard transmission gear changes that used a slight disengagement of the clutch. you could see at every gear change where there was no power to the tire. you would be amazed at how much time and speed is lost with clutch disengagment. maybe your gearbox can be modified for full power shifts or possibly use a split second electrical disconnect of some kind. the main thing, you want to change gears up with no clutch disengagement.

another technique used on the clutch is a contraption that bolts to the pressure plate and allows a slight slipping of the clutch plates on initial take off so 100% of the power isn't immediately transmitted to the tires, resulting in major traction loss or engine bogging. it has a bunch of weighted fingers that compress the clutch plates tighter as centrigigal force increases. similar concept to what top fuel drag racers use I suppose, although they wouldn't have engine bogging but certainly would have major tire spinning and no traction

on a small methanol engine you might be fine with a free flowing gravity system but theres several mikuni pumps that work good if you need it. http://www.mikuni.com/fs-carburetor.html. I use the 65l/hr pump on my 500cc engine. not sure the correct heat range plug but I always used the #9

[Haufen]

I've been thinking this for the last couple of weeks and I still can't decide.What's best power curve for a drag bike?
As much power as you can get in a small rpm range and power droping out quickly,or less power with a wide usable rpm range and a lot of overrev?

Go for whatever gives the highest average hp through the gears you want to use (you can use the powerrange concept to do this, for example). Typically, a wider usable powerband than needed is a bit more forgiving and improves consistency between the runs as it is not that important any more to catch the shift rpms exactly.

[wobbly]

Everything comes down to the rev drops between gears, this dictates how hard you can lean on the bmep number to create peak power vs band width.
Depending upon the final egt number you generate the pipe will need to be shorter, due to the lower gas temp and the com needs to be thru the roof.
125 cylinder can use 19:1 as an example.
The ignition curve should be as was optimized on petrol and the plug should be an 11 when running very high com or it will create deto around the body due
to overheating.
Dragging is all about creating heat quickly in the pipe so small stingers are the norm as is full throttle staging and air assisted up shifts, easy with an Ignitech or similar.

[SwePatrick]

Broad curve is a must to get it to behave koncistent.
A small peaky engine only produces good runs when you are hitting the powerband perfect.
And that is really difficult with small twostrokes.
The small ones are always faster with variodrive, as it is easier to make koncistent small adjustments to find engines 'sweetspot'.

As the yankee´s always have stated: 'There´s no substitute for cubicinches'

I use a shiftcutter with adjustable timing, this cuts the ignition when hitting the gearlever, this lets me shift gears with no clutch.

The more difficult to get off the line the more timeloss

One should never forget that the start is the most critical moment in dragracing, this is where you are spending most time per meters.

Rgds
Patrick

[husaberg]

that looks more compact than the other bosch posted previously but I think its l/m output might be less. I wonder if the pump wobbly posted isn't the best so far ? although it doesn't give any size dimensions or weight.

it is low ouput, Its only 15l/minute
The first one is about 50 liter/m
https://www.kiwibiker.co.nz/forums/s...post1131025463
its about a 1 KG i think, i have two here.

[adegnes]

FLoatbowl well seemed to do the trick. Responds good to jetting now! The future is bright!

[husaberg]

FLoatbowl well seemed to do the trick. Responds good to jetting now! The future is bright!

https://www.youtube.com/watch?v=DUSPpB9__fU

That new fuel might have made a pretty big diference as well

[F5 Dave]

Ambient temp can't be hurting. I've spent about 5hrs today in warm muggy dyno room chasing missing power, how much due to atmospheric. . also trying to fuel map (sorry its my foulstroke 675) in a room that needs ventilation. Getting the curve/map even, but needs so clean runs to verify baselines.

So you calculate like 5hp loss in the variator thingy. That would make it get very hot in short order.