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Post by colinlinz on Jan 10, 2010 11:29:24 GMT 10
Mattjin, I agree with your comment about the snorkel size being the limiting factor. I have been on about this for years with the VTR - I reckon it is too small. But if you open up the airbox the carbs cannot handle it regardless of any jetting changes - I have tried plenty. So with my EFI swap I will be using a modified airbox, which will be based on the SP1 set-up. It has a much larger intake than the VTR, about times the size. What you have to remember is the the whole intake system has been designed to work as a whole. Any major change to one component will effect the operation of the others. You could dump the whole air box and run open carbies, and they would work fine as long as you picked the right carbies. You would suffer some loss of midrange, but outright power would be good. You could remove the snorkel or open up the airbox, but you won't get any significant gains unless you change other aspects of the tuning. In your case (Shayne), moving to SP1 EFI throttle bodies is obviously going to necessitate an airbox redesign (both for mechanical and tuning reasons). For that matter some head work and a custom exhaust system my also be worth doing to take advantage of your mods. Of course now that the engine is going to go better and develop it's power a little differently you will have to think about suspension and brakes. You have CBR brakes fitted, so that is sorted, but with the additional braking power, and engine performance you may need to get those RaceTech valves re-shimed to help stop some of the diving under your aggressive braking, or the rear suspension squatting from the newer aggresive power delivery. Now you could go on and on, but the point I'm making is that any major mod will necessitate a range of changes to other components before it will work properly.
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shayne
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Post by shayne on Jan 10, 2010 12:03:41 GMT 10
Stuff around with the airbox with the standard carbs and you will be in a whole world of hurt. I know because I tried!!! It will be all good in the end.
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Mattjin
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Post by Mattjin on Jan 10, 2010 13:37:55 GMT 10
That is the big benefit to EFI, it does not rely on air flow to draw the fuel into the intake, so you can design the airbox however you like.
I will still say from alot of experience converting back and forth from single and multi throttles, that there is no benefit to multi's other than packaging and response. You just need to get the lengths correct, and even a reasonable taper on the intake will be enough. A good case in point here too is the Honda S2000's F20 motor. It will run out to near 10,000rpm and it uses a single throttle even though it was designed to be at the pinnacle of power/displacement. More recently I work with the K20 series motors also running out to high 9000rpm and found no benefit to multi's, and this is a class dominating sports sedan.
The multi's will use a throttle plate diameter dependant on where in the taper they are located. It is why some are larger than others, but it is rarely to do with power. Going larger also makes the throttle action more responsive. 10% open on a 60mm throttle is alot more air than a 40mm throttle. There are a number of things to consider before diving in, as you can see.
Good to see the mention of brakes and suspension in the same area as talking about power. Something too many only realise after they are looking down from above.
Oh yeah Colin, it is Jin Ba and not Jimba, two words. Man (and) Horse and not Manhorse the mythical creature. :-)
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Post by colinlinz on Jan 10, 2010 16:12:58 GMT 10
Yes, you don't need to worry about air velocity and venturi effects. I would expect wave resonance and air momentum to still be of use though. I really have no experience with using different throttle bodies. My thoughts were just based on observations of what I see the factories doing. For whatever reason, they still seem to like the multi bodies on most bikes, and the bikes that don't use them are the ones with moderate rpm. Romanisation of Japanese is confusing. I've seen the Japanese write things together and separately. I have done a Japanese martial art for the last 22 years, some time ago there was a massive international debate over the way it should be written in romanji. It had been always referred to as Shorinji Kempo or youthful forrest temple fist method. At one stage it was proposed that we should be writing it as Shorinjikempo. Then it all changed back again. In this case joining the man to the horse is good as it further emphasises the "ittai" aspect, or the oneness of the two. I stole it from Mazda, it was the inspiration behind the Mazda MX5. When I first read it I liked the imagery so I adopted it as my sig. Then I dropped the bike and Shayne had to miss his lunch www.shorinjikempo.or.jp/wsko/
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Mattjin
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Post by Mattjin on Jan 11, 2010 18:08:06 GMT 10
haha. I remember Mazda using that to describe their goal for the MX5, and also remember them mentioning for the RX8.
I have been learning chinese (mandarin) for around 5 years and regularly travel in and around asia. Having a chinese wife helps too. Chinese and Japanese basically use the same written system, but the vocal words are completely different. So they can read each others writing but cant speak the other language. When learning pinyin (romanisation of chinese script) I have generally seen the pinyin written as seperate words when the characters represent seperate meanings. A short example is "yiyuan" which written in this way means hospital, but if I wrote it as "yi yuan" it would mean one dollar. I am disregarding tones here of course. In chinese, Ren Ma Yi Ti (LREN MA EEE TEE), meaning the Man and Horse as One System/Body. I love the philosophy too, and use it as part of the thought process when setting up a track car. The more connected you are, the easier it is to go fast and not screw up.
Lucky for me I also have Korean, Japanese, and Malaysian friends so asian translation is never a problem for me :-)
I was doing some thought today while out on the bike, on whether a MAF sensor would be a good way to go or not. Other than the intake pulsations, it would do well with the low manifold vacuum that our bikes have at idle.
Another thought is that once you go EFI, it is really easy to setup a nitrous kit ;D Handy for catching the newer CBR's and GSXR's.
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Post by colinlinz on Jan 11, 2010 18:57:42 GMT 10
haha. I remember Mazda using that to describe their goal for the MX5, and also remember them mentioning for the RX8. I have been learning chinese (mandarin) for around 5 years and regularly travel in and around asia. Having a chinese wife helps too. Chinese and Japanese basically use the same written system, but the vocal words are completely different. So they can read each others writing but cant speak the other language. When learning pinyin (romanisation of chinese script) I have generally seen the pinyin written as seperate words when the characters represent seperate meanings. A short example is "yiyuan" which written in this way means hospital, but if I wrote it as "yi yuan" it would mean one dollar. I am disregarding tones here of course. In chinese, Ren Ma Yi Ti (LREN MA EEE TEE), meaning the Man and Horse as One System/Body. I love the philosophy too, and use it as part of the thought process when setting up a track car. The more connected you are, the easier it is to go fast and not screw up. The Japanese do use many Chinese kanji (sorry, don't know the Chinese term), but there are also many they don't use. They also use the kanji in conjunction with their own hiragana and katakana, so it is a bit of mix and match. I have formally studied Japanese, but not enough to read kanji, just recognise some. I can read hiragana and katakana, but that only gets far enough for children's stories. The Japanese art that I do has very little in translated material (even all the admin is in Japanese). Out of the 6 books I own on its techniques and philosophies, only one is in English, and it has been out of print since the early seventies! My language skills have suffered though, as it has been a while since I've needed to use them in a non training context. I've competed a couple of times in Japan and toured through the country staying at friends places, but not in recent years. A friend of mine has lived there for the last 20 years, he is a professional translator, mainly working with large corporations, he has also translated some classical texts that have been published. I should ask him Here is an example from one of my books. You may notice the mixing of language. I've got to go and buy Pizza now, just been told. I'll get back to the real discussion a little later
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Post by colinlinz on Jan 12, 2010 10:31:02 GMT 10
We rarely use them in the marine industry, some inboards and stern drives do. You don't see them on bikes often, I can't think of one off the top of my head. I'm currently evaluating a motorcycle technology text book for work, so I thought I'd have a look in it and see what it had to say. While it has a chapter on EFI and describes various inputs and outputs and shows typical wave form patterns, it doesn't mention MAF sensors. I thought I'd try to find some credible information on MAF sensors and bikes. About the best I could find was a book published in 2002, so it is a little old, but it does mention MAF sensors in context with motorcycles. tinyurl.com/ykhsenv
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shayne
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Post by shayne on Jan 12, 2010 14:13:59 GMT 10
I will be using the factory Honda sensors, as already mentioned, so they should work fine I reckon.
As for throttle bodies, as far as I am concerned with a street bike, smaller bodies will promote airspeed at lower revs, and improve torque and throttle response. In a race application it would not matter, but for me I want the two smaller bodies rather than a larger one.
The Honda S2000 you mention is a good case in point. Road tests reported that it produced great power for a small engine, but was rubbish below 6000rpm (from memory). I am not interested in producing more peak power than I have now (although I suspect it will). I am interested in the power delivery. I don't want more peak power and less bottom end response.
This is one of the reasons I am using mainly factory Honda gear for the conversion. It is a known quantity, and will minimise development I think.
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Mattjin
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Post by Mattjin on Jan 13, 2010 22:53:27 GMT 10
Shayne, you could utilise a Honda throttle body too, from the S2000. Off the top of my head I believe the idle control is built into the throttle, and is a simple 2-wire BAC-type PWM controlled unit. Easy to run. The throttle body size wont really change the power curve if you are running a single TB. It will more be the diameter and taper of the inlet that does this. My general advice is for a 2deg taper all the way out, but honestly with these motors you could just run the port size out to the plenum and not loose anything. Just get the length right. Single TB should be of benefit anyway if there has been talk about EFI being too responsive. It should smooth the power delivery a little more from closed to open throttle. The bigger the volumne of air between the TB and the inlet valve the softer the response will be.
Also Shayne be careful sharing sensors if you are going fuel-only. You will have to make sure there are no pullup resistors on the ECU you choose, otherwise it will effect the the existing ignition ECU. Some of the good ECU's will allow this to be done in software.
The S2000 actually has a very linear power delivery, just most people hear the changeover of the VTEC and think it hits and takes off when it is only the noise change.
MAF is quite a good way to go if you can give it a clean signal. It wont care about the low manifold pressure, and wont be too effected by altitude changes.
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Post by colinlinz on Jan 14, 2010 7:42:04 GMT 10
Mattjin, You got me thinking in regard to the single throttle body. What you have said is quite true, yet I don't see it reflected in bike engines. It would be much less expensive for bike manufacturers to go to a single throttle body, but they don't. I'm guessing their are reasons for this and I would like to understand them better. So far I've come up with very little information that is motorcycle specific, and I may have to wait until I go back to work. I have some contacts at Honda and Suzuki's technical departments, so perhaps they might have the answers. I did find a couple of Automotive sites that talked about the advantages and disadvantages of ITB's. I'll post a couple of quotes and the site links below. So what are the advantages – and disadvantages - of individual throttle bodies?
David Thomas, head of Racing Performance Works (RPW), is an expert in Mitsubishi, Proton and Hyundai vehicles and has developed several individual throttle packages to suit. According to Mr Thomas, the biggest advantage of individual throttles is they don’t scavenge air from other cylinders and there’s a virtually unlimited supply of air to the engine.
“In a naturally aspired engine with a high compression ratio and big cam there is great potential for power,” he says.
“Throttle response is also amazing. In most instances, the actual throttle opening – the total opening across all cylinders – is higher for your given throttle input. I’m just picking figures but you might find that an individual throttle system has the same airflow at 15 percent throttle input as the standard throttle at 50 percent throttle input. But that will depend a lot on the size of the throttles.”Second quote. Q: What are the benefits of individual throttle bodies? A: Individual throttle bodies allow the engine to operate more efficiently by decreasing pumping losses to achieve more horsepower. The runner length can be tuned, injectors placed at optimal positions and angles, and air flow speed maximized. The system can be tailored to the engine displacement, compression, cylinder head valve train design.
A properly tuned system can dramatically improve throttle response and decrease intake tract restrictions to increase horsepower.
Manufactures typically prefer the single throttle body design as the system is much less complicated and less costly to produce compared to an individual throttle body system. autospeed.com/cms/title_Multi-Throttles/A_3049/article.htmlwww.scienceofspeed.com/sos_resource/FAQs/general/natural_aspiration/ITB_induction/
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Mattjin
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Post by Mattjin on Jan 14, 2010 14:42:12 GMT 10
Besides the fact that more air passes the throttle plates at say 15% throttle than a single TB would (depends on the size of the single TB though), what causes the better response is the volume of air between the throttle plate and the intake valve. The best way to talk about this is to take things to the extreme.
1. If the throttle body is right next to the valve, as you open the valve the vacuum will drop almost instantly because the volume of air can be displaced quickly due too it's small size. Most likely this will happen in one engine cycle.
2.Now go to the other extreme, we have a single throttle with the plenum the size of our fuel tank. More air needs to be drawn through the motor to cause the same drop in vacuum. At this large volume it will take many engine cycles to reach the same level.
I have tuned so many multi-TB setups on many different engines over the years, that I have lost count, and if I were injecting my VTR I would go with a single. For most of us the response from having acceleration enrichment as well as correct AFR would be already vastly improved. But I am sure most of us would agree that response is not something our engines lack anyway. I personally would find it easier to ride if it were not so snatchy at low rpm. Nothing worse that going around a small suburban roundabout where 1st is too high and 2nd is too low, and going on and off the throttle makes it jump around.
You have to also consider that most bikes are 4-cyl high revving engines. They will naturally run well with a short intake, so in that case multi-TB is a better option for packaging reasons. Getting equal flow to all four runners in a plenum when you have limited space is not an easy thing to achieve. Whereas our twins have plenty of space with an easy to design inlet setup. In the end the choice is down to personal preference, with both single and multi TB setups having positives and negatives, but generally if the design is done correctly there is no real power difference. It is just packaging and reponse to consider. Multi's also make it harder to do an idle control system, something you need to consider to keep the motor running when it is cold.
OEM's have other considerations. Singles dont need synconising, it is easy to do the idle control, and response is normally good enough for normal use when compression is high enough. And it is cheaper.
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Mattjin
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Post by Mattjin on Jan 14, 2010 14:54:00 GMT 10
We pretty much do the same with our shop. We custom fabricate pretty much everything in a vehicle, with the only thing we dont do is paint and trim. Roll cages, brakes, engine conversions, turbo and superchargers, chassis building, radiators and intercoolers, and not to mention engine management which is my specialty (I also have a background in Physics from UWS). 4, 6, 8, and rotary engines too.
My best advice for building an inlet would be to get the injector location, size, and spray pattern correct as it will have the biggest impact on how well the conversion works. Choose injectors that will cope with around 15% more power than you will ever need. Going larger makes things worse, and going too small is a disaster. Next is to mount them as close as possible to the intake valve, even if you have to drill and weld to the head. While you are at it, angle the injector so that it aims at the the junction of the valve stem and head. Next is to choose a spray pattern so that the angle of the spray lines up with the outer edge of the valve head. If you get all of these right you will find the engine so much easier to tune, response will be great no matter how bad the rest of the design is, and the engine will be more tolerant of lean conditions without causing hesitations.
The whole principle is to get the fuel into the combustion chamber with the least possible influence from anything, and do it in the shortest possible time.
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billzilla
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Post by billzilla on Jan 14, 2010 15:36:45 GMT 10
Choose injectors that will cope with around 15% more power than you will ever need. Going larger makes things worse, and going too small is a disaster. Next is to mount them as close as possible to the intake valve, even if you have to drill and weld to the head. FWIW a good rule of thumb for choosing injector size is 5.5cc per hp. So if you're going to make say 70hp per pot in a VTR then a 385cc injector will work fine. I'll have to disagree about mounting the injectors close to the head though, every test I've ever seen has the engine making more power with the injectors as far out as possible. On a car engine that I'm building (1626cc, 9500rpm, 240hp) it'll have eight injectors; four in the inlet manifold after the quad throttles and they're twin pintle types so the spray pattern doesn't wet anything other than the valve head backs, and the other set of four will sit out in the inlet trumpets for when I go to more than about 30% throttle. The second set are single pintle and are set so they give the longest droplet path into the head. They're also timed injection as well so the injector only fires as the inlet valve opens so there's no fuel droplets pooling on the port walls.
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Mattjin
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Post by Mattjin on Jan 14, 2010 19:07:08 GMT 10
The motors I have done with injectors mounted just inside the trumpets generally make such a tiny amount extra power that I would not bother with the complexity unless absolutely every last scrap of HP is required. It does make a difference, but the amount of difference will depend on the quality of the spray pattern of the primary injectors. If they atomise very well, as do most recent injectors, then you will find very little gain. If they are an older injectors with a dirty pattern then you will most likely see gains that are worthwhile.
The reason you get a gain is because you have more of the fuel in gas form than liquid if there is more time in the inlet to vapourise. IMHO up until the early 90's you would get good gains, but these days I would be surprised to see more than fractions on a modern engine.
Which engine is it Billzilla?
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billzilla
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Post by billzilla on Jan 14, 2010 19:50:25 GMT 10
A lot of the gain is also because the fuel droplets have longer to travel to the combustion chamber and are able to soak up more heat from the inlet air. But as you say it might not make a huge difference on small engines though I can't see why it wouldn't. The engine is a somewhat modified Toyota 4AFE. It's got a 7AFE head, pistons from Wiseco that I designed myself, longer con-rods, Group N crank, dry-sumped, bigger valves, etc. A mate of mine in Holland built one much the same and got 248hp at the crank at 9,000rpm. I reckon mine will be better.
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Mattjin
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Post by Mattjin on Jan 15, 2010 10:01:37 GMT 10
Cool! I have done many 4A based engines over the years, from high rpm NA to high boost turbo and supercharged types. Good luck with it, they are a tough engine for their size but they are very fussy with intake length and diameter. I once spent 7 hours on the dyno getting a 4AG inlet just right. Modify, retune, repeat...repeat...repeat...
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billzilla
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Post by billzilla on Jan 15, 2010 14:00:46 GMT 10
I use Engine Analyser Pro 3.9 - It gets it right first time.
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Post by colinlinz on Feb 5, 2010 14:57:02 GMT 10
This isn't really related to the thread. I just thought some of you would like to see some different styled injectors to the norm. From left to right. Evinrude's ETEC injector. A direct injected two stroke engine. This is a unique injector. Unlike other injectors that are basically a pintle valve being turned on and off. The ETEC injector is like a speaker coil. The supply fuel pressure is about 30psi. This pressure is increased by the injector up to 600psi. The injector uses rare earth magnets and up to 55 volts to generate a variable force on the injection of the fuel. It can vary both stroke and pressure as required, and has some advantages over other DFI 2 stroke systems. The main one being that it can inject fuel faster into the combustion chamber. This allows the motor to achieve it injection while all the ports are still closed. Some others still loose a little of the charge out the exhaust ports as they can't move the fuel fast enough at high revs. The second on is the ETEC's predecessor. This is the infamous Ficht injector. It works similarly to the more advanced ETEC, but was plagued by reliability issues. The third is a Yamaha HPDI injector (two stroke). This works just like a normal injector. It is just much larger, and injects directly into the combustion chamber. This system uses a mechanically driven fuel pump, the fuel rail pressure is around the 1000psi mark. The fourth is a Mercury Optimax direct injector (air injector)(two stroke). This is an Orbital designed system. The engine drives an air compressor to pressurise the air rail to around 90psi. The fuel runs through a series of pumps that supply the fuel rail with 100psi of fuel. The injector shown injects fuel and air into the combustion chamber. There is a conventional style injector that sits above the air injector, it injects the fuel into the air ports above the direct injector. The fifth is a conventional injector out of a Mercruiser MPI (V8 Ford). The 1/2" uni joint is just there to show scale. The Optimax is my personal favourite, it is well sorted and reliable. It is also being used by Aprilia on some of their bikes The ETEC shows immense potential, it is a shame Evinrude don't have any design partners. The system is very unique and relies totally on Evinrudes resources for development.
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shayne
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Post by shayne on Apr 27, 2010 16:05:33 GMT 10
I reckon this will be my ECU. When in last looked it was still under development, but it is now for sale. Not going to buy it yet, as there is no point just now. After my new property is sorted out I can get back on to the project again. adaptronic.com.au/products/e1280s.html
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Post by colinlinz on Apr 27, 2010 16:27:17 GMT 10
I'd do it before you build your shed. These ecu's are fairly small, and you will no doubt loose in that monster shed you're building. I have a hard enough time remembering where I put things in mine, and it is half the size of yours.
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shayne
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Post by shayne on Apr 28, 2010 10:07:29 GMT 10
Next issue to sort out will be the injectors. The Denso 12 hole injectors fitted to the VFR800 and CBR1000 for certain year models are the same part, and these fit in the SP1 throttle bodies when you mix and match the seals. They fit perfectly. ;D
The VFR has one injector per cylinder, where the CBR has two. The SP1 also has two, but they are set up differently. The SP1 has two injectors of the same size, on on each side of the throttle body in the same position. The CBR has two different injectors, one mounted in the throttle body, and one mounted further up the intake. In the airbox from memory.
I will keep the SP1 injector positions as standard. This will be easier, as this is where they are supposed to go, so the TB has the hose for it and the fuel rail fits up as well.
So the question is what injector size to use. Factory SP1 4 hole injectors are all the same size, so clearly that will work. The Denso 12 hole injectors I have identified as fitting the TB's are used in both the VFR and CBR so clearly they will operate across a wide range. In the case of the VFR, one injector fuels a 200cc cylinder, in the case of the CBR, a 250cc cylinder, but only to a certain point when the second injector will operate.
So do I use 2 of the 12 hole injectors in each TB, or try to use a different injector for the second one in each TB? I am leaning towards two of the same at the moment.
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Post by colinlinz on Apr 28, 2010 17:54:56 GMT 10
I'd probably go with the SP1 injectors, just purely because the engines are so similar and the manifolds you're using are off one.
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shayne
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Post by shayne on Apr 29, 2010 19:25:32 GMT 10
I'd probably go with the SP1 injectors, just purely because the engines are so similar and the manifolds you're using are off one. They are 4 hole, that is why I was not going to use them. Fitment is not a problem, as the later 12 hole injectors fit perfectly. The only issue is do I use two of the same size in each TB, or try to get a different size for one of them. I expect that at low revs the first injector will operate on its own, before the second one opens at higher revs. Any benefit to one being smaller for example? These injectors will do a 200cc cylinder, so they will deliver small amounts of fuel accurately. My hunch tells me that they should be fine.
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Post by colinlinz on May 2, 2010 20:50:59 GMT 10
The only reason I thought to use the SP1 injectors was fuel spray pattern. Flow rates are probably similar, just the SP1 injector locations would probably suit the SP1 injectors better?
Usually the up stream injector is used at higher revs, and sometimes rapid throttle openings. I'll fire up my lap top and see what I can find on them. The software doesn't run on my iMac.
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billzilla
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Post by billzilla on May 3, 2010 9:33:15 GMT 10
Any benefit to one being smaller for example? These injectors will do a 200cc cylinder, so they will deliver small amounts of fuel accurately. My hunch tells me that they should be fine. No need to guess - You need about 5.5 cc/min per horsepower so a 200cc injector is good for about 36hp. I suspect each cylinder on your engine would make more than that. I'd be using twin pintle (hole) injectors and align them so they squirt at the face of the valves. The injectors with more than two holes can sometimes have oddball spray patterns so I tend to stick with just the two holes.
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shayne
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Post by shayne on May 5, 2010 9:29:42 GMT 10
The only reason I thought to use the SP1 injectors was fuel spray pattern. Flow rates are probably similar, just the SP1 injector locations would probably suit the SP1 injectors better? Usually the up stream injector is used at higher revs, and sometimes rapid throttle openings. I'll fire up my lap top and see what I can find on them. The software doesn't run on my iMac. Dunno. It is possible that the 4 hole and 12 hole injectors will have different optimum distances away from valves etc. My gut feeling is that the new 12 hole injcetors will be an improvement. They use the 12 hole units on the SP2, although I acknowledge that the TB is different and there injector position may be different as well. The 12 hole SP2 units have a different part number to the 12 hole CBR/VFR injectors, which I know will fit. The SP2 injectors may not.
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shayne
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Post by shayne on May 5, 2010 9:34:02 GMT 10
Any benefit to one being smaller for example? These injectors will do a 200cc cylinder, so they will deliver small amounts of fuel accurately. My hunch tells me that they should be fine. No need to guess - You need about 5.5 cc/min per horsepower so a 200cc injector is good for about 36hp. I suspect each cylinder on your engine would make more than that. I'd be using twin pintle (hole) injectors and align them so they squirt at the face of the valves. The injectors with more than two holes can sometimes have oddball spray patterns so I tend to stick with just the two holes. The VFR injectors are not necessarily 200cc. Who knows what they are. I was referring to cylinder size. The problem I found with OEM parts, is that you cannot get specs for them, so I don't know how many cc's the injectors are.
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Post by colinlinz on May 5, 2010 12:54:18 GMT 10
You can put them in an injector tester and measure them. That is if you have one If you want them measured let me know.
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shayne
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Post by shayne on May 5, 2010 16:07:03 GMT 10
You can put them in an injector tester and measure them. That is if you have one If you want them measured let me know. That's handy to know. Thanks for the offer.
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Mattjin
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Post by Mattjin on Jun 20, 2010 21:20:28 GMT 10
The best advice I can give you is to go for only the 2 injectors, and leave the other two unconnected. If you are going to run 4 injectors and you are planning to stage them. i.e. run 2 then turn on another 2 further up the rpm and load range, think long and hard about doing this. It is not as easy to blend the pairs as you may think, and even with alot of experience it is still not an easy job to pull off and that is with a car, not a bike that is even more difficult. The OEM's generally do it because they need the fuel supply for much higher rpm and power outputs, but still want perfect ridability, and biggest of all... they have the ECU specifically developed for that engine. Running an aftermarket ECU to do this is not quite so easy. You need tp pick an ECU that can run staging while still sequentially injected, and you need good control of how they transition.
Going with just two injectors will make life much much easier. Given a choice, you want them to spray towards the inner radius of the valve (so usually on a bike, on top of the manifold). If you run the 4 injectors all of the time you miss out on more accurate targetting, with one set spraying where you need, and the other spraying on the other side of the port.
You also want to make sure the ECU will do TPS/MAP blending, as almost all bike ECU's do. They will generally have a common vacuum tank source from both throttle bodies for manifold pressure, which is used as a correction over the top of normal TPS main mapping.
The 1280s should do OK, but it is rather new and a little clunky to use the software. Just be sure it is bug free before diving in. It is also a rather large unit for use on a bike.
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