| Author | Message | ||
     M1combat  |
How does stroke length affect the proper timing curve of an engine? If it doesn't affect the curve, I assume you would adjust the static advance if you stroked an engine. In the case of our sequential injection... Would you also want to advance/retard the injection timing by the same amount as the spark timing if you increased the stroke length? Is the Techlusion capable of supplying enough extra fuel to meet the demands of going from XB9 fuel delivery to XB12 fuel delivery levels? | ||
| Martin |
I would assume that its not the techlusion, but the injectors themselves that are the limiting factor. I have heard that BMW1150 injectors flow more, but am trying to establish the 9r flow rate to do a comparison. If you fit 'bigger' injectors you may have richness all the way through the range that a techlusion cannot 'take away'(Unless the increased flow of your stroker exactly compensates for it)There are tables available showing injector flows but you do need to know your baseline with the standard injectors. Since the tables are for multi-cylinder car motors they may also be under-efficient compared to a Buell.(!) | ||
| Steveshakeshaft |
Whilst a question solely about injector specs would be a bit off topic, the folks here- http://autos.groups.yahoo.com/group/megacycle/ Will tell you the answers to your injector questions. The site hasn't many members and can be a bit slow. But you should get answers. HTH. Regards Steve Shakeshaft www.ukbeg.com steve_s@ukbeg.com | ||
| Trenchtractor  |
M1, I'll do my best at this one. 1.How does stroke length affect the proper timing curve of an engine? Well, 0, 90, 180 and 360 degrees of the crank in the engine cycle are all the same relative to the cam pos sensor, regardless of stroke. The position of the crank is the reference for your timing/advance calculation. Consider this, at a given rpm, it takes the piston the same amount of time to get from BDC to TDC, regardless of stroke. The ideal point where the ignition should be initiating spark is at the same time before top dead center because the real reference is once again at the position of the crank. Also, you may have noticed that when we discuss why we have a redline of less than 7,000rpm while other Jap machines get 15,000rpm, we constantly remind everyone that the limiting factor is not crank speed, but piston speed. If your stroke is twice as long and you want the piston speed to be the same you have to half the rpm. 2. If it doesn't affect the curve, I assume you would adjust the static advance if you stroked an engine. I'm not sure exactly what you are asking here. Are we talking about the static timing or the advance curve. The static timing is a figure refering to the amount of degrees BTDC that the ignition system has to initiate the spark so that by the time the air fuel charge is ignited, the piston is at the right point for the explosion to transfer load in a downward fashion. The reason your timing is lets say 10 degrees (as a generic figure) before top dead centre (BTDC) is because at idle, it takes 10 degrees of crank rotation for the spark to ignite the air fuel charge. As rev's pick up, the time this igniting of the air fuel charge does not decrease, but the time it takes for the piston to travel 10 degrees of crank reference reduces, so the ignition needs to initiate the spark earlier to ensure the explosion happens at the same point in the crank cycle. This is called advance. Once again, it's all about the number of degrees BTDC that everything needs to happen, so theoretically you should not have to change any of the ignition system, unless you are trying to upgrade for a better spark. 3. In the case of our sequential injection... Would you also want to advance/retard the injection timing by the same amount as the spark timing if you increased the stroke length? I don't feel any change is required there either. Once again, the injectors would be starting to fire as close to when the cylinder is set for the intake cycle (near TDC), the piston has areound 180 degrees of crank to draw in the air fuel... This will take the same time at the same amount of revs regardless of the stroke lenght. Once again, you see the stroke is irrelivant to some extent. 4. Is the Techlusion capable of supplying enough extra fuel to meet the demands of going from XB9 fuel delivery to XB12 fuel delivery levels? In your profile it says you're riding an XB12... I wonder if this project is for the 12 or the 9. However, I will say that if the injectors are the same and you are going from 984ish to 1203ish, you could quite easily go to the 12 ECM which will, out of the box, fire the injectors for longer. Of course this theory relies on the fact that the injectors are the same part number on both models. If not selecting the bigger injectors would be the go (but who didn't know that). There was also a point that there is an alternate ROM for the TFi, that allowed for twice the level of adjustment... If you were to fit it up and there wasn't enough there, you could sent it back to Dobech and have the 'bigger' ROM fitted... So, everything I have said here is perfectly sound in theory. When it comes to the internal combustion engine, however, we all know theory wil only get you so far... Hope I've helped you understand the answere to your question, not just lumbered you with a bunch of Blah Blah... | ||
| Trenchtractor |
I'd just like to add that I don't know how the increased air fuel charge will affect the time it takes for the charge to ignite... This 'may' have an impact on the timing advance. | ||
| M1combat |
So... The stroke length shouldn't have any major effect on the spark curve, the static timing or the timing of the injector pulses... Can we assume that the timing curve of a 9 is the same as a 12? I was intentionally vague in my initial questions... Here's what I'm going for - Can we use an XB9SX ECM in an XB12? I'm not going for a 7500RPM redline as such, but I would imagine that someone running on salt with an XB might be interested in this. The reason for choosing the CX ECM specifically is because that TB already has the larger diameter that the 12 does. I would imagine one would want to use the 12 injectors (if they are indeed different). Add the techlusion box, and theoretically you should be able to adjust the fuel level so you aren't too lean. I don't think I would want to do this to my street bike, but if it's possible, I would certainly buy a 12 for a track bike instead of a 9. I would basically be getting a "reasonably free" 1200 kit on a 9, but getting there by stroke instead of bore (personally I prefer over square, but I'm sure that the under square config of the 12 has it's advantages. I seem to remember someone figuring the piston velocity on a 12 at some point and it was right at or just above the 4317FPM "best practice" limit. | ||
| Glitch  |
Yer sneeky! Good food for thought. | ||
| Blake  |
I doubt very much that the timing curves for an XB9 and an XB12 are the same. I also think it would be terribly risky to assume that "stroke length shouldn't have any major effect on the spark curve, the static timing or the timing of the injector pulses." And as discussed previously, there is no way to to adjust static timing without affecting fuel injection timing. Two different engines, with two different displacements, with two different rev limits, with two different intake tracts. The timing for spark and EFI will be the same? I doubt it very much. Probably wouldn't hurt to give it a try though, on a dyno with an A/F sensor. In fact, I'd pay money to see that done. Hmmm, who do we know with access to a dynamometer? Pammy? Aaron? Hoser? DaveS? If anything, it seems to me that the larger displacement with a larger combustion chamber putting out more power at WOT for the same RPM would require more spark advance in order to get things optimally burning. Have you considered getting a racing license so you can get one of the fully programable ECMs?  Fun stuff. I still like carburetors better. | ||
| M1combat |
See that's the thing... I think it would require some adjustment to the static timing, but we can adjust that relatively easily (a LOT easier than trying to fiddle with making our very own spark, FI and advance maps...). It really is a good question for the likes of Aaron or Wes... When you stroke an engine, what do you typically have to do to the fuel delivery and the spark timing (static and curve)? "Two different engines, with two different displacements, with two different rev limits, with two different intake tracts. The timing for spark and EFI will be the same? I doubt it very much. " Well, I don't mind if they are not the "same", but can a "useable" tune be found by adjusting the static timing a couple degrees either way... Also... The intake tracts are different? Are the valves a different size between the 9 and 12? Aren't the heads the same? The 9 heads already operate at 7500 "just fine" so one of my many assumptions for a project like this would be that the 12 heads should operate just as well at that RPM. The (obvious) issues would be fuel delivery, timing and piston velocity. Are the 12's that close to the edge of the PV limit that the engine would grenade after two dyno pulls? I don't know... Quite frankly... I don't have the money to even attempt to find out... Mostly just thinking in text, but I am very interested in the discussion of whether or not it's possible. It seems to me that the largest hurdle would be the fuel delivery, and Dobeck seems to have solved that one for us... The 1200 tube frames... Do they handle 7500 RPM's for any length of time? If not, what would it take to make that stroke length survive at 7500 RPM's? I assume slipper pistons, good rods and Axtell cylinders... Are the bearings approaching their load limits? So far from my point of view, I'm looking at this from the perspective of just adding a 9CX ECM and Techlusion box to a 12 and making ONE dyno run to see exactly what happens (My luck probably a fiery explosion...). I would probably make some educated adjustments to the techlusion to get in the proper ballpark. I'd probably ask Aaron, Wes or Pammy about how much more fuel I might need in which RPM ranges and then talk to Dobeck about how to achieve that with the Techlusion and then... Go for broke I guess... No guts no glory. "Have you considered getting a racing license so you can get one of the fully programable ECMs?" I would if I could afford it. Maybe next year . | ||
| Blake |
The throttle body for the XB12s is bigger. You cannot adjust ignition timing without also changing fuel injection timing. Please trust me on this, I have it on good word from the experts, the bike will not run well if the cam position sensor timing goes away from the specified setting. Sure, the 1200 engine will rev to 7,500 okay. Heck, mine has been run up to 7,500 on a dyno more than once. I wouldn't do that on a regular basis though. The engine just won't live as long. I ain't telling you anything you don't already know, I don't think. A simple start would be to dial in 25% more fuel at ALL rpm. My logic is that you have 20% more displacement, and about 20% more power with an extra 5% thrown in for safety at the higher RPM where if power continues to climb it could reach over 20% above a stock XB9. For a WOT run that should hopefully keep you from going too lean. Too rich won't blow your engine. Do it! Really fun stuff! | ||
| M1combat |
"The throttle body for the XB12s is bigger." Not bigger than the CX TB though... Is the part number for the CX race ECM the same for the regular 03/04 9's? If it's the same, Buell has decided that the extra TB diameter won't affect the fuel delivery (unless they just figure it's OK to run one or two higher AFV points). If it's different, then the fuel requirements for the new larger TB on the CX are different. If the ECM's are different between a 03/04 9 and the CX 9, I would use the one from the CX because it has the same TB as the 12 (I don't know about the injectors though). | ||
| Blake |
Interesting. | ||
| M1combat |
Yeah... That's what I thought when this scatterbrained idea popped into my head. | ||
| Trojan  |
The race ecm for the CX is different to the regular XB9 one. How different I just don't know  | ||
| Reepicheep  |
I have a 9sx stock ECM that I will volunteer for a dyno run if somebody wants to spring for a TPS reset. That being said, to be honest, I would not do it if I were you. If I were to do it again, I would stick with my stock ECM, and add a techlusion box. Going from the stock 9sx ecm to the race 9sx ecm gave me about 1.5 horsepower (opened up airbox, stock exhaust). I had an accidental experiment where they originally put on an older (pre 05) race ecm when I bought the bike. Top end was about the same, bottom end had a more pronounced hole then normal, but overall the bike ran pretty well. So I don't think they are a lot different, just tweaked maps. | ||
| Blake |
It turns out that the throttle body for the XB9SX is the same bore as for the XB9R/S, it just incorporates a one piece configuration, where the older versions were two piece. The new one piece configuration does change the intake tract enough to warrant a different ECM mapping. | ||
| Opto |
I thought they were using the XB12 throttlebody? | ||
| Blake |
Me too. But it ain't true. Don't know how that rumor got started. I thought I saw it in print somewhere. Straight from the Buell Web Site...
| ||
| Trenchtractor |
Yeah, Blake, my comments were al theoretical... You could proly tell that the way it was written... Plus my 'All good in theory' disclaimer. I would imagine it would be easy for someone to look up the respective part numbers for the 9 and 12 injectors. They are proly the same. I also thought the new 9 used the 12 throttle body. Interestingly enough, I verniered (digital, cos I'm lazy) the throttle body on my '04 12, it's 48.9mm average around, based on 3 measurements, at 4 different points. The 12 measurements ranged 48.87 to 48.92mm. Anyone gonna measure their 9SX??? Reep made a really interesting point that got me thinking... The Pro series ECM's are more advanced than the stock ECM's in all cases... It's one of the reasons you get more power out of the race ECM. If you were to use the stock 9 ECM on your 12 and found you needed more advance, then go for a race ECM... Ignition advance isn't really a big deal, so long as you aren't too advanced, that's when you'll have detonation and reliability issues. The way I see it, if anything, the 12 needs greater advance than the 9 so as to ignite the bigger slowere moving air fuel charge. If the 9 ECM is too retarded, you'll just find it has less mumbo. As for the fuel, well if the injectors are the same, then the only difference in the map that matters is when they start to fire. If the cams are the same in both bikes, then the injectors will proly start firing at the same time in both bikes. If that's the case, you just add fuel using your TFi, since all it does is extends the duration of the injector pulse (true?). I reckon you need the following: 1. Someone with a 12 and the balls to let this test go ahead, 2. 9S/R Stock ECM 3. 9SX Stock ECM 4. 9SX Pro Series ECM 5. 9S/R Pro Series ECM 6. Timing lamp 7. TFi The test would be to use the timing lamp to get an idea of the advance of the 12 ECM.. I winder though if there is enough visibility through the vindow for the timing mark to read advance...?? Then go ahead and test each ECM out of the 9's in a logical order, and note the differences... Like I said before, the fuel is easy... | ||
| Blake |
"The Pro series ECM's are more advanced than the stock ECM's in all cases... It's one of the reasons you get more power out of the race ECM." More advance does not necessarily produce more power; more fuel will (assuming initially EPA compliant emissions). How do you know about the race ECM having more advance in all cases? The way I see it, if anything, the 12 needs greater advance than the 9 so as to ignite the bigger slowere moving air fuel charge. You may be right about the advance, that would be my guess too, but the bigger engine's intake charge will be moving significantly faster not slower, more intake charge, same rpm, same time to fill cylinder. I also think you are making a huge assumption wrt the fuel. You may be right, but you may be WAY off base too. Try not to make assumptions about anything that might cause trouble if you are wrong. I like the idea of simply hooking up a 9's ECM and dialing up a techlusion module to boot up the fuel by 25%. Still not without risk though. But I fully support your effort to try it. ![: ]](http://www.badweatherbikers.com/buell/clipart/proud.gif) | ||
| Trenchtractor |
I want to have a more detailed look at this, but don't have the time right now... Tomorrow... | ||
| M1combat |
Me too... I'd probably be willing to give this a shot after doing some looking into how long this stroke length might last at that RPM. I sure it will lower the expected lifespan of the engine, I just don't want it to lower it to say... 12 revolutions . | ||
| Trenchtractor |
Sorry Blake, I was typing as I was thinking in all previous posts... Time to think a bit before I open my mouth to insert feet.  Ok, upon reflection... 'More advance does not necessarily produce more power; more fuel will (assuming initially EPA compliant emissions). How do you know about the race ECM having more advance in all cases?' When we were tuning our air cooled VW motors to get the absolute best power, we used to set the timing to 10 degrees BTDC, as per the most aggressive spec VW suggested, then constanlty advance them up in small increments until they would ping under load, then back the timing off half a degree. Once we knew what the setting was for that particular motor, we'd use that setting for all successive tune up's. Lower grade fuel would force us to set the timing less advanced, you could advance the timing in winter, but had to back it off come summer. Some motors would allow more advance than others, sometimes you'd have more compression and had to set the timing less advanced, other times you'd have a bigger capacity (my personal motor was a 1916cc based on the 1600cc dual port) and would get even more advance. For the leaner running motors, you could use less advanced timing, if you added more fuel, you could advance the timing up... But that didn't always result in more power. We were using the ever popular 009 mechanical advance dizzies, so the advance curve was based on revolutions. So, applying what I know from before helped us (including the Buell tech) that if we retarded the timing 2 degrees on my race kitted 12, the pinging went away. We then fitted up the stock ECM to find there was no more pinging. Now, the ECM provides fuel and spark maps. More fuel would reduce the tendancy to ping. We know the race ECM has a richer fuel curve, I have A/F dyno charts to prove it. We also know that while more advance can improve performance, excessive advance causes pinging... You see where I'm going with this?? So, the race ECM on my bike had more advance than the stock ECM. Extrapolating out that it's widely accepted that optimal advance = better performance and I would say that the race ecm's have more aggressive advance. Also, my bike with a race ECM works with octane booster or 98RON fuel, but not acceptable on 95RON. With a stock ECM, it runs ok on 95RON fuel. So while we have proven in our own experiments (with a Buell tech) that the race ECM in the 12 has more advance than the stock ECM, I did extrapolate this over the entire race ECM range... But having said that, I think it's an entirely fair assumption to make in this case. 'The way I see it, if anything, the 12 needs greater advance than the 9 so as to ignite the bigger slowere moving air fuel charge.' You may be right about the advance, that would be my guess too, but the bigger engine's intake charge will be moving significantly faster not slower, more intake charge, same rpm, same time to fill cylinder. I guess what I meant here was that it would take longer for a larger A/F charge to pass through. Your point about the bigger charge moving faster is true, same time to fill the cylinder, the piston moving faster at the same RPM so greater suction... All that stuff. But I still think it would take longer... 'I also think you are making a huge assumption wrt the fuel. You may be right, but you may be WAY off base too.' Yeah, I know it is an assumption, but I'm pretty certain that the relationship to when the cam opens the inlet valve and when the injectors fire is pretty much fixed at optimal... It'd have to be. Why would Buell set it up any other way... So having said that, if the cams were the same, or the cam on both models opened at the same time, then the injectors would fire at the same time, too... Or very close to the same time. Perhaps a CRO with 1 trace set up on the cam position pulse, the other set up on a spart wire P/U and a third on the injectors would give you a window to the relationship.... But you's have to do that test at a constant RPM... The you still wouldn't know if the advance curve under accelleration was different because it would just be too hard to compare... Perhaps there is specific equipment that would allow the reading of the parameters, but where's the fun in that?? | ||
| Trenchtractor |
I was just thinking... We need to get the 12 and 9 part numbers for the cams and injectors... If they were to be the same, use the TFi with the earlier 9R/S stock ECM. This is based on the injectors being the same, cams being the same the injectors would fire virtually at the same time (ish), and like I said before, I think the 9 would be less advanced. Like you said blake, more fuel is the safe option, but so is less advance... I think, though, M1, that the higher RPM redline would make for exciting riding, but jeez you'd wanna do your research on piston speed well... Also, we're hearing more and more that the ROM's can be re-flashed... Perhaps if the new diagnostic tool could make use of this we could simply reflash ye olde ROM with the same data, but higher redline... Then you could set the redline to 7,000 for a safer option to 7,500... | ||
| Blake |
Too much "I think", not enough, "I know." Its difficult to debate that kind of logic. Again, I suggest you stick strictly with what you know in cases where if what you "think" turns our to be inaccurate, your engine risks catastrophe. I sure would like to learn how with the same cams and the same heads at the same RPM one engine could take longer to fill its cylinders than another. By definition, they will take exactly the same amount of time. One may fill more optimally, achieving a higher volumetric efficiency, but they will each fill in the same amount of time. And again, you insist on talking about retarding the timing. If you try to do so on an XB you will also retard the fuel injection timing and risk all kinds of problems. The ECM ROM is reflashable? Absolutely. What chip based ROM isn't? If I recall correctly, back in the day of new Buell '99 DDFI bikes, Buell techs were showing up at some Buell events and upgrading via scanalyzer the ECM firmware on customers' '99 X1s and S3s. But figuring out how to do so is not a trivial matter. You'll most likely first need to figure out how to defeat some type of security code to gain access to the firmware. Talk is cheap, I hope you go ahead with your experiment and let us know how it comes out. I sure am interested to hear what happens. You just might happpen upon one of the easiest high performance uprades for an XB12. I know a certain land speed racer in Australia who will be very interested in your theory and its real world results. Then again, you might blow up your engine too. That's what makes the idea so intriguing. Good luck. | ||
| M1combat |
Yeah, we need to get the part numbers for the cams... If the cams are indeed different (or at least if the relation to valve opening and injector timing are different) that could certainly cause some pretty "neat" problems. Somewhere I seem to remember reading that the lifet may be higher on a twelve... If that's the case, It's almost a safe bet that the rest of the profile has differences. Different enough to really affect the proper injector timing... That's above my engine building head. If the cams are the same though... The 1203 is 22.25% more displacement than the 984. Is the couple mm added to the TB diameter enough to allow the TB to flow 22% more air at the same velocity? My assumption is that the heads are the same, but I don't know. I'm sure I can find out though. Piston speed... Yeah... That's a fun game . I saw a piston go through the hood of a Hemi charger once . LOTS-O-SMOKE. I was in the passenger seat. I suppose that was probably a combination of speed and sideloading though. I seem to remember someone doing the math on that a while back and decided the 12's are closer to the "reliable" limit than the nine already. You're right though Brad... 5000-7000 coming out of a third gear corner on a 12 would be a VERY fun ride. | ||
| Opto |
2004 Lightning Model cams "P/N 25188-02A 'E' CAM GEAR SET w/pinion gear" for 9's and 12's, any country. The 49mm throttle body has 18% more area than a 45mm body. Aaron posted a dyno of his shop M2, I'm sure it wound out to 7 or 7.5k with 120 HP or so. I think Aaron would have a good idea of the upper rev limits for an XB and how to get there, so it's only a phone call away. | ||
| Trenchtractor |
Thanks Opto... I couldn't for the life of me find the spec's on the cams, though. I will say that no one seems to list 9 aftermarket cams and 12 aftermarket cams separately, but that's the aftermarket world... Blake, I know about the electronics side, that's my trade, although I try and keep that quiet. And ignition isn't my concern... I'm satisfied with my experience, what I know about ignition and what I've had to learn about my bike with fixing a chronic pinging problem. If someone else is/isn't happy with something I say, I am disclaiming that I'm talking theory without any proper research other than off the top experience. Fuel isn't my area. Like I said earlier, the internal combustion engine rarely plays along with the sort of basic theory we are discussing... Next problem, is I on't really want more RPM outa my 12. I like the idea of a slower reving road bike... If Don's looking into race applications, this might be the cheapest way to do it... I'm not about to try it on my bike, not for fear of fuel/ignition issues, but for fear of the damage the higher revs will do **to a stock engine**. I had a piston that ended up tapping on the head becasue i was young and stupid and thought another 500rpm wasn't going to hurt the motor. I thought the guy that built it was giving me 'head room'... Seems the redline he told me to stick to was acurate. I had the motor independantly stripped down, to be told it was reved too hard... Seems I didn't know better then, but I do now. Actually, I'd like to know if we can reduce the redline of a 9... shouldn't be too hard. If we could do that easily and effectively, I'd be more interested in this as an experiment. Then you could offer it as a mod to allow the 6,800 or 7,000 redline. That way we could use the TFi and the stock ECM with a 'better' redline. ATM, however, I am happy with the TFi and my stock redline... I know it'll last, and since my bike is my commuter, that's important to me. The guy you are talking about land speed racing might be the guy who has a mate in Ayr, NQ. If he is, Ayr is about an hour from me. He asked me once before about getting more rev's, since they were hitting the rev limiter... As soon as I saw M1's question, I thought of that... I've lost his number and eamil, so I can't contact him, if he was interested, though, I'm willing to research this deaper, working with the local dealer as a point of reference for the OEM numbers... It's Sunday night here, so we've had a couple of days lost just in discussion... I will be having a talk about this tommorow. Point is my local dealer is usually up to offer support in the way of info and numbers... They encouraged me to do the 'R' conversion and even gave me cut prices so they'd know if it could be done... This is good for me, I'm dredging up stuff I haven't had the think hard about for several years... Even when I was working on solving the pinging problem on my bike, the thoughts were purely anecdotal... Injector part numbers are next... If they are the same part number, then we try and find some crazy nut who wants to try this with a TFi... | ||
| Trenchtractor |
And again, you insist on talking about retarding the timing. If you try to do so on an XB you will also retard the fuel injection timing and risk all kinds of problems. Blake, this is actually an experiment the dealer did to try to prove that the advance was the problem on my bike. Actually the bike ran fine, I rode it. I dissagree with this as a solution to a problem, but it made the pinging go away for the short while (half a day) that it was set this way. I was simply theorising that the 12 would likely have a more aggressive advance curve... That's my thought, anyway. This is (as you know) set by the ECM. So if the 9's advance curve is less aggressive, then to use the 9 ECM in the 12 would mean less advance. We're not changing the OEM cam position setting or static timing, but refering to the advance curve. Having the less aggressive advance curve is the safer option, ie, it makes this experiment less scary. What chip based ROM isn't? ROM - Read Only Memory This doesn't mean it's re-writeable. Some chips do not allow more than one upload. Now, my dealer was not aware that they could update the XB ROM's... That's not to say they weren't updateable, but give me a break here, the word was that my ECM couldn't be 'fixed' with a new load if there was an alternate map... The new map could only come in the form of a new ECM... That's what's coming down to me officially. What I read here has to be treated as rumour until it's substanciated, for obvious reasons... Who can you trust?? | ||
| Opto |
Injector part numbers are next... If they are the same part number, then we try and find some crazy nut who wants to try this with a TFi... 04 XB9S injector P/N P0786.02A8 XB12S front injector P0026.1AA, rear injector P0027.1AA. The 2 P/N's for the 12 are for "specific spray patterns" according to the FM, but they're interchangeable on the 9... I would imagine the FI systems of the 9 and the 12 to have reasonably similar WOT injector duty cycles. This could be checked at idle and say 3k rpm with a CRO on one of the injector leads on both a 9 and a 12, if the pulsewidths are similar then I would think that the 9 ecm with TFI could feasibly do the fuel injection for the 12. |
