supra5677
Pro
Posts: 1279
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posted April 25, 2006 09:16 AM
ZX12R Muzzy issues
When you change the header and exhaust in the car, you always have to go with larger injectors.. Why arn't we doing this with motorcycles? We are using this stupid power commander which in nature is limited in its capability. I had a muzzy exhaust and could NEVER get it to idle right so I yanked it and put on an Akrapovic. My theory is because of the Muzzys larger diameter header and scavenging its starving out the cylinder and making the idle lope. Why don't we just match the Muzzy exhaust with the proper injector size for example 370cc? On carb bikes we jet the main jet, needle, and pilot until we get it right, the principles are the same with fuel injectors. My buddy and I have an idea to match the right injector size to the muzzzy exhaust.. Anybody else have ideas?
supra
   
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your car is slow
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posted April 25, 2006 10:24 AM
since when do you have to change injectors in a car merely by bolting on some headers?
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supra5677
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posted April 25, 2006 11:47 AM
example Dodge SRT 4
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osti33
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posted April 25, 2006 12:40 PM
I've put headers on LOTS of cars and never changed the injectors... 
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supra5677
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posted April 25, 2006 01:17 PM
slip on exhaust no jetting req
full system jetting req
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your car is slow
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posted April 25, 2006 02:29 PM
 Edited By: your car is slow on 25 Apr 2006 15:30
your example is a turbo car? get real man.
also....what the hell does jetting have to do with anything on an FI bike.....welcome to the world of powercommanders.
Some of your posts really leave me scratching my head....but yea...you go ahead and swap out those injectors before your motor goes boom!
I wouldnt ride it until you get them swapped out!
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supra5677
Pro
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posted April 25, 2006 02:44 PM
I got my muzzy customed mapped twice and still couldn't get the muzzy to idle right.. Thats why I yanked the muzzy and put on akrapovic.. I even called factory pro in calfornia and he couldn't get the damn thing to idle right even! He couldn't even get it right at certain throttle positions.. I have spent many hours on this so scratch your head it you'd like. The principles of air and fuel are the same whether its a carb or fuel injected bike..
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your car is slow
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posted April 25, 2006 04:19 PM
Edited By: your car is slow on 25 Apr 2006 17:19
im sure there is an exhaust / injector matching chart on the internet somewhere. Maybe muzzy pipes just dont play well with RC injectors like Akro pipes do....try some accells...or bosch!
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blitzkrieg
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posted April 25, 2006 04:41 PM
The injectors have nothing to do with it.
Think about what you typed above supra. l)
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CrotchRocket
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posted April 25, 2006 05:58 PM
Supra...Look every pipe out there is different !!!...They all have different characteristics but all make basically the same HorsePower, but in different areas!!!
You need to do your own R & D to see what you like...Just because a certain pipe does not perform the way you think it should, it does not mean it has problems...
You do not need to change anything after installing a pipe!!!
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dougmeyer
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posted April 25, 2006 06:53 PM
Supra
The stock injector size is sufficient for the small increase of flow required by the addition of a pipe. Just look at the duty cycle on the PC III read out. The numbers are right there.
If you're referring to the lopey and hunting idle, that is caused by the lower back pressure of the Muzzy exhaust. Do a search. it's been explored and explained to death.
D.
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TurboBlew
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posted April 25, 2006 08:42 PM
does the relation of air to fuel mean anything???
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supra5677
Pro
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posted April 25, 2006 09:27 PM
ive always had the stock injectors on my 12r.. But I always thought the Muzzy had more potential than the akra even though for me the akra works better.. thanks guys..
supra
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havabusa12r
Expert Class
Posts: 425
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posted April 25, 2006 10:06 PM
quote:
ive always had the stock injectors on my 12r.. But I always thought the Muzzy had more potential than the akra even though for me the akra works better.. thanks guys..
supra
The EZ solution was to just turn up your idle speed a little at a time. It'll smooth out at about 1500? The lope never bothered me.
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tuusinii
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posted April 26, 2006 04:01 AM
The injector size wont matter at the idle at all because engines use so little fuel on idle compared to high RPM full throtlle openings where the injector size will matter if it is too small. And just changing a exhaust will only affect the Hp reading in the region of 10% at max so it will also need max 10% more fuel and You would expect the injectors to be overrated more than that. In theory the problem comes if You have to use a duty cycle of over 100%, or in realily probably a little earlier.
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Y2KZX12R
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posted April 26, 2006 04:48 AM
Every Injector has a %duty cycle where the injector starts to loose its precision on off capability. It depends on what type and who makes the injector. Typically (generally) an injector should never be over 85% duty cycle. That means the injector shouldnt be on more than 85% of the total cycle time it is alowed. The available cycle time (the available time window to inject the fuel) depends on the rpm and the on time depends on required fuel for that rpm. So as the cycle time decreases with rpm and the fuel required increases with rpm the injector must shoot the required fuel in xx seconds. So if the injector needs to use the entire cycle time thats available to keep the desired airfuel ratio the injector is always on (energized) and the injector has gone "static". However, injectors are electro mechanical, and so have a required amount of time to "open and close". So this time needs to removed from the available cycle time. Then there is rail pressure stability issues as well as a few other issues that i wont bother to get into. So all said and done this is how the 80-85% is derived.
Of course none of this applies to an injector that is using 3% of ita available cycle time as in an idling engine. The computer can simply add to the on time of the injector.
The idle quality stems from varrying reversion caused by the duration of the cams. And is made worse by removing backpressure in the exhaust.
Three ways to solve it.
Reduce the duration of the cam lobes to reduce reversion.
Add back pressure to stablize the reversion.
Or dont let the engine idle in the range where reversion is fluctuating.
Bottom line, the injectors arnt the problem.
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supra5677
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posted April 26, 2006 08:28 AM
Simple question: With larger injectors with the Muzzy exhaust will this normalize the idle?
The akrapovic and of course the stock pipe idles perfectly. People are adding 20-25 % more gas with the pc3 to normalize the idle(muzzy exhaust) Instead of using the pc3 why not a slightly larger injector and forget the power commander?
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your car is slow
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posted April 26, 2006 09:03 AM
if you havent realized the answer to your simple question after reading all these replies....im afraid someone will have to tattoo it on your forehead.
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supra5677
Pro
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posted April 26, 2006 09:06 AM
sombodys got to think outside the box, Im okay if its me..Bottom line is countless guys are taking off there muzzys and changing to different pipes because of drivability. This isn't good for Muzzy and as far as Im concerned performance. I know a guy who yanked his Muzzy off and put the stock pipe back on!
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Y2KZX12R
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posted April 26, 2006 09:27 AM
Supra, the yosh rs3 race duplex pipe has the same idle problem.
Each bike has different cam timing from the factory so some bikes will idle hunt more than others. But in any case adding fuel to stableize the idle hunt is just masking the problem and will result in a rich idle mixture.
Is this idle hunt objectionable to you?
Have you ever heard a V8 engine idle with a big fat cam in it? Anyone who knows anything about engines will recognise that the bike has big cams when they hear the idle hunt.
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supra5677
Pro
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posted April 26, 2006 09:38 AM
I just read an old post from Crotchrocket. He took off his Muzzy also and put on an akrapovic. I read the similar posting on Labusas.org and zx12r.org. As far as Im concerned the power commander masks the problem by adding 20% more gas at the low throttle positons. And if Mark Salvisburg at Factory Pro can't get it right at other throttle positions not just the idle even up to 5500 rpms this tells me there is something else going on. I know big block Chevy's with big cams are lopey but this isn't my point. The stock ecu is much more sophisticated than the power commander. Which begs the question why are we using it in the first place? In carburated bikes you add fuel in the pilot, needle, and main jet, seems like the ecu can do the same given the right size injector for the specific application.
I guess nobody has tried a larger injector with the muzzy and absolutely no power commander. So when my wife goes out of town I'll get started on it 
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Y2KZX12R
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posted April 26, 2006 10:58 AM
The ecu in these bikes is very very low tech. Its abilities are very very limited. Its a "dumb" computer that sees this and does that, using static tables. If you compare it to a computer in a GM car it would be like comparing a light switch to a PC.
With that said, I have to agree with you on the muzzy pipe and also the ti force pipe. Both have driveability issues down low. But not all pipes have these driveability issues.
Factorypro is a direct competitor to dynojet so understand that people have agendas.
He doesnt have tuning link software to work with the powercommander and dynojet dyno.
So he will need to tune the powercommander map manually. That is if he has the patience or willingness to do so. You really need to have a map made on a dj250 with tuning link.
But unless you are at 45 on the powercommander chart and its still lean then you dont need bigger injectors. If you really wanted to add more fuel across the board you could always raise the fuel rail pressure. This is the same thing as using higher lb per hour injectors. Again, its not your problem thou.
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your car is slow
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Fuck Nitrous...Got Boost?
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posted April 26, 2006 11:14 AM
this is getting even more amusing.....
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wannabe
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posted April 26, 2006 11:23 AM
quote:
this is getting even more amusing.....
+1
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supra5677
Pro
Posts: 1279
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posted April 26, 2006 11:32 AM
Jim your making me laugh.. your a tough customer I did read and re read Doug M article on fuel pumps... more fuel pressure would do it..
I just got frustrated because 2 different dyno shops custom mapped my Muzzy and couldn't get the f***king thing right. When I do put my Muzzy back on I would be inclined to try the Muzzy fuel pump..
Thats funny you said the bikes ecu was low tech.. As far as performance Superbike Mike said the bikes ecu was tuned to the optimum. When he tried the Motec ECU he netted only 1 rwhp. I know a 16 bit ecu has less parameters than a 32 bit etc..mmmm
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