MeanBean49
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Posts posted by MeanBean49
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26 minutes ago, snoorder said:
OK, I finally have an update on the Street Triple 675 R wheels. Fitting the front was easy. 32 mm spacer on the left. Some 8 mm on the right so the axle doesn't go in too far. Space the discs 3 mm out or the calipers 3 mm in.
Rear wasn't too bad either. Note I am using a 750W swingarm which is 10 mm wider at the back so gives more room to play. 19 mm spacer on the left centers the wheel and lucky me gives a perfect chain alignment. Now just fill the right with some spacers and RSV1000 brake setup.
Very cool. Is the sprocket offset 100mm from wheel centre as standard on these then?
May have to keep an eye open for a set
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31 minutes ago, Samikoo said:
Yes you do, because saying the same thing over and over does not clarify it.
So you assume the draw through has a greater vacuum than a na engine? Why? And no, I'm not trying to wind you up!
I understand the reasoning with barometric pressure vs. carb outlet pressure. But how come the draw through carb outlet pressure is less than that of the na engine? And I'm not comparing two engines with the same displacement. Please sir, you are an expert on all things flowing air. Explain, I do want to learn.
It less because the turbo is creating a greater vaccum than an N/A engine is.
Its not positive pressure until after the turbo.
The problem is being able to get the slide to react properly.
If your at closed throttle at quite high rpm, the turbo is spinning creating quite a lot of vaccum, you open the throttle a little bit, but you get a massive initial airflow because of the big vaccum, pressure differential is huge, and you get fully open slide and more float bowl pressure, and then massive excess of fuel dumped into the motor at once.
Its transitions in throttle position that are the problem, not max flow, or constant throttle, or max cfm stuff.
If CV's worked or were easy to get to work then tgats what people would use instead of spending a fortune on expensive carbs
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37 minutes ago, Samikoo said:
How does the pressure differentiate when in a draw through system compared to a na engine?
Edit: And why does an su carb function in a draw through design?
Do I have to tell you the same thing again!
On a draw through, your only affecting one side of the carb. So the pressure is way different on one side of the carb which makes the differential way more than under normal n/a operation or in blow through operation where you have the same increase or decrease on both sides of the carb.
This means the slide will not function properly.
Lets put some fictional numbers on it to help.
N/A inlet side 1 bar, outlet side 0.5 bar pressure differential carb is designed to operate with 0.5 bar
Blow through, system inlet 3 bar, outlet side 2.5 bar, pressure differential 0.5 bar, carb functions as normal
Draw through, inlet side 1bar, outlet side 0.25bar, pressure differential 0.75 bar, carb cant function as normal, slide will not work properly and float chamber cant function right either
You proably can mess about and get one to function somthing like at different pressure differential but I doubt it would be easy, and would be trying to get it to work at a different velocity as what was designed, and likely to still have issues on transitions from WOT to closed and vice versa
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13 minutes ago, Samikoo said:
I'm still not buying this. A cv carb functions solely on vacuum, and an su carb is a cv carb. Ea constant velocity.
The reason I mentioned cfm was to clarify that a carb only understands the air sucked through it, or pushed if it's a blow through system. How on earth could a cv carb work on a big bore twin if it could not handle a huge vacuum? The carb does not know if the air is being sucked through it by a na engine or a turbocharger.
Bear with me here, I'm an automotive engineer so I overcomplicate things.
Whether you buy it or not thats the reason.
A CV carb does not function on vaccume.
It functions on the pressure difference between inlet and outlet
When you increase an engines capacity you increase the volume drawn in, but you do not change the pressure differential between inlet and outlet.
When you have a blow through system you increact the volume through the carb but you do not change the pressure differential
When you have a draw through you massively change the pressure differential and the slide will not work properly.
Im a degree qualified aeronautical airframe and jet propulsion specialist, and its not complicated at all.
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2 hours ago, Samikoo said:
So how come an su carb works on a draw through setup? It's function is also based on the vacuum created by the engine. I'm not trying to argue here, it's just that I still can't figure out how, let's say a 1300cc na engine or a 750cc turbocharged engine, would make the carb act any different, if the cfm through the carb would be the same?
An SU carb only relies on vaccum only.
A CV carb relies on a pressure difference between inlet side and outle side. Has nothing to do with cfm.
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1 hour ago, Samikoo said:
But some have accelerator pumps and push-pull throttle. I've seen them on Hurley Durley aggricultural machines.
And the only thing a carb sees is sucky sucky, right? When the turbo starts making boost, it just sucks more air through the carb. I'm having a real hard time understanding how the carb could sense that it is feeding an air-fuel mixture in to a turbocharger instead of a naturally aspirated engine. I guess I'll have to bite the bullet and try one out myself.
See my response above.
A CV doesnt just rely on the airflow through the body, it uses pressure differential to open and close the slide. On a blow through system the pressure differential between inlet and outlet of the carb is the same as in N/A use.
In draw thru the differential is much much greater due to their being way more vaccum at the outlet side than the inlet. This means the slide cant work properly
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14 minutes ago, Simbec1863 said:
Cheers @MeanBean49hopefully a retorque will sort it,otherwise I’ll be in touch,appreciate the offer
No probs mate.
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11 hours ago, Simbec1863 said:
First test of the runt blandit preseason today at Mallory.
It was dry for once and the runt ran the best it has since 2019.
Quick check at the end of the day and a slight weep of oil from the head gasket and the sight window has started to leak,hopefully a retorque of the head bolts cures it and a probably need to replace the sight window before the leak becomes a flood
Worst case scenario, pop to mine and borrow my motor. Not getting time to put my race bike together at the mo.
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5 hours ago, Samikoo said:
So what exactly is wrong with a cv carb on a draw through desing?
Iirc its because of the pressure difference between ambient and the outlet side, it stops the slide opening/closing properly, or can make it open/close too quickly depending on what the turbo/engine is doing
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Head upside down with plugs in, pour some petrol in the combustion chambers and watch for a bit, if they empty then they are not sealing and could do with lapping in.
Whether you need to start with coarse and then have to do again with fine will depend on how bad they are. I generally find 99% of the time fine on its own will do the job
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3 hours ago, CphRider said:
Maybe, but it doesn't look that cheap to me. That's why I asked
May not appear cheap, but it looks very very similar to the hundreds available from China for £20 on teebay. Got one myself (brown one) to use for cutting and mock up so i can have a decent one made right
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Yes it will work perfectly fine.
But save all the agro, goimg round in circles and going on jetting advice of others.
Dont bother wasting money on a dynoshit kit, ot will just make it harder to get setup well and end up being shite on fuel.
Get it to a decent dyno place that actually knows what they are doing, pay for some time and a set of jets to suit.
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2 hours ago, motopsycho87 said:
Nah I'm going to change it. Again was looking at turbo maps which are for lower compression motors. Stay tuned for v2
Where you getting your turbo map from?
My turbo ran best with a standard ignition curvre. But I had big intercooler.
Generally non intetcooled setups people end up with about -3 or 4 degrees off max advance to keep it safe
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4 hours ago, motopsycho87 said:
Ahh, 1 post further back. Stock ignitech TPS map has a huge hump in it around 10-20% throttle. If you just add 5deg to everything it gives a couple points around the mid 50s, hence I didn't like it and changed it
Like I said earlier the stock tps map is just a generic thing, its not intended to work, you need to imvest in a lot of dyno time if you want to use this function and get it setup right.
Thats because these bikes didnt have a 3d map in the first place.
Ignitech just supply a 2d map mirroring the standard curve that is ok to use as is.
If you making any changes to the map without doing it on the dyno then your pissing in the wind really anyway. I personally wouldnt want to be running 40 degrees of advance at low throttle openings, not likely to be doing your motor any good
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5 hours ago, motopsycho87 said:
You might want to read my post again... Lol
Read it again, still says 55!
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3 hours ago, motopsycho87 said:
I've just copied what exists and adjusted based on reasonable guesswork. It's an improvement on the standard unit +5deg
What have you copied to end up at +55?
Max standard advance is 36 degrees iirc, how you +5 to that and end up at 55 I dont know. 55 is likely to grenade your motor
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8 hours ago, motopsycho87 said:
The stock ignitech maps are rubbish. I enabled TPS and it gives you a mental amount of advance between 2 and 10% then goes flat again, adding 5 degrees to this puts you at about 55' !!! It also gives a horrible surge if your coasting at low revs in a high gear. I've studied a ton of maps and used a generator also going from what I know is safe and made one that works pretty well. Dropped down to 30 degrees at full throttle and it absolutely rips with a ton of torque down low. Will post when I get to work in the morning.
Anyway, what's this secret I missed? PM me
As far as im aware the 3d map they come with isnt inteded to be used as is, its just generic, because these bikes dont have 3d maps as standard.
A b12 has tps, but its only setup to retard ignition slightly in lower gears.
The standard 2D map is a copy of the standard ignition curve. Ive foumd it always works fine. Usually get the best from stock motors by adding 3-4 degrees to max advance.
3D mapping your only going to get right wuth hours of dyno time, set it all to match the standard map and go from there, you need to be doing loads of dyno pulls at each throttle opening to see what works best. I have heard investing time in a good 3d map is worth it on a road bike, makes running really smooth and improves fuel economy quite a lot.
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1 hour ago, Dezza said:
Can someone just tell him the diameter of the specific speedo, main body and top bit, if possible? I do not understand the need here for any unpleasantness
He started it, ner ner ner na
And we still have no idea exactly what it is he wants to know, if you need to know the size of somthing so you can fill the hole its left, then you must have the hole to measure instead?
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47 minutes ago, Marc clayton said:
Ffs
it was a simple question, they was no need to jump on my shit “coherent fucking sentence”
you all knew what I bloody ment
If it was simple you would have got a simple answer.
Was you who got shitty about the first answer you got and hence the following less serious responses.
Going out on a limb now and guessing what you may actually want to know is what width is the speedo drive?
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1 hour ago, Marc clayton said:
Butcher??? I don’t have one to measure
or I wouldn’t of asked
So your not getting rid of it then like you origionally stated?
And if your filling the hole it left, measure the hole.
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2 hours ago, ElBlandito said:
@MeanBean49I had asked about the stock B12/GSXR maps not being available in the latest .exe download drop down from ignitech and assumed you may have to purchase a unit to have that option available in the software. @Gixer1460was saying that's kind of wrong to ask for the info, so I wiped the post. Mistake on my part.
My point still stands, a bandit or gsxr ignition curve is not a top secret thing only ignitech know.
They got it from somewhere in the first place, its not their property in the first place really.
Not looked at mine in ages, cant remember what they come programmed with.
If you want either map just email ignitech and ask for it, they will email it over. Ive done it a few times when i have swapped one of my units onto a different bike.
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2 hours ago, Gixer1460 said:
Its a bit necky to technically be 'ripping off' a companies maps to use in someone else's software without paying for it!
Whos ripping anything off? Talking about a standard ignition map, as supplied by ignitech to go onto another igmition map.
Not that an ignition map/curve is a top secret thing anyway. Suzuki and every other manufacturer seem happy to make them common knowlege
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6 hours ago, motopsycho87 said:
Would still be interesting to see 750 map, there is so little information on getting a good ignition map out there it seems like it just needs to be ride, adjust, ride, repeat... Without a dyno of course
Igntech has them all available, you just select it from the dropdown.
Iir 750, 1100 and b12 are pretty much all the same, just slightly different rev limits
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Just add however many degrees on the map where you want them and click programme
Lightest wheels for a slingshot
in Oil Cooled
Posted
Cool, only 5mm more than slingy, thats not too hard to sort