Removing CAS, any thoughts?

[Swedish Mike]

I thought about removing the CAS and mount the trigger teeth on one cam, then drill a hole in the cam cover and mount the new sensor there.Another option is to mount it on the rear part of the cam.

Ever seen this before? I´m talking standalone EMS now and Bosch trigger sensor.

Just want to get rid of that ugly old piece on the cam gear and use billet adjustable gears with full view.

[dattodude]

Sure it's been done before.

Getting access to adjustable camwheels is certainly good for tuning and "bling factor".

I would guess that the aftermarket ECU could handle crank trigger or cam trigger for the ignition. We've seen some members here move to a crank chopper wheel.

Letting rocks and dirt near the timing belt is a catastrophe waiting to happen though. Good for a dyno, or car show, but that's all.

You could do nothing, and spend more time with your family or friends instead :-)

Cheers.

[Swedish Mike]

Sure it's been done before.

Getting access to adjustable camwheels is certainly good for tuning and "bling factor".

I would guess that the aftermarket ECU could handle crank trigger or cam trigger for the ignition. We've seen some members here move to a crank chopper wheel.

Letting rocks and dirt near the timing belt is a catastrophe waiting to happen though. Good for a dyno, or car show, but that's all.

You could do nothing, and spend more time with your family or friends instead :-)

Cheers.

Haha, yeah, know all about that. I´ll use a cover but not the stock one.The EMS want both cam and crank angle, need to put trigger wheels on both.

Any pics of this? Did they mount the sensor on top or in the end of the cam?

[dattodude]

The ECU needs a signal to tell where the pistons are at, so it can fire the sparkplugs at the correct time. This would mean mounting a chopper wheel on the crank, or setting up something near the cam wheels. You would need to talk to your ECU manufacturer on the most approprite method for the particular ECU.

I've only seen CA18 engines mount a trigger off the crank, or use a CAS.

[Swedish Mike]

The ECU needs a signal to tell where the pistons are at, so it can fire the sparkplugs at the correct time. This would mean mounting a chopper wheel on the crank, or setting up something near the cam wheels. You would need to talk to your ECU manufacturer on the most approprite method for the particular ECU.

I've only seen CA18 engines mount a trigger off the crank, or use a CAS.

As I said before, I need both crank and cam triggers, just wanted to know if someone had some good cam trigger solution in store.Most serious EMS´s use both for exact ignition and spark, the cam belt flex and going crank alone is a bad idea.

I will solve it but not sure if I want to mount it in the cam cover or in the rear end of the cam.

[float_6969]

Why is crank triggering alone a bad idea?

[Swedish Mike]

Why is crank triggering alone a bad idea?

It´s ok if you use an old type EMS but the new ones with seq injection/ignition need a cam trigger to tell the ECU what position you´re in.Two crank revolutions (and only one cam rev) per cycle is to much for a crank sensor, it can´t keep track of what position the cams are in.

Hard to explain in English but trust me, I need both. It´s also a great help to make the engine run perfect even if the belt get longer with time.

[dash]

if the belt flexed, got longer with time or whatever... the valve timing would be out of sync with the piston by that amount. What purpose would it serve having the ignition event out ?

I wouldn't call crank or cam trigger only, a "bad idea". Simply take one look around at all the millions of excellent performing motors using either one. So they don't run perfect now ?

[float_6969]

Well as far as sequential fuel injection is concerned, I don't really see any performance benifits of it. I can see the benifit of sequential timing if you're running the motor in a high rev sitation where your charge time for the coils is at minimum.

As Dash said, Crank or cam only timing has been around for a long time and works quite well. If the cam timing is out, do you want the spark timing to not change? I wouldn't think so. And considering the computing speeds the ECU's are capable of today, do you really think you can spin a motor so fast that the ECU can't time the spark events reliably? If it IS turning that fast, then I doubt this is a street motor. Wait, there ARE street motors that turn that fast, they're sport bikes and I'm pretty darn sure they don't use both cam and crank signals.

I'm not saying it's a bad idea, I just think it's superflous, and has little gain for the energy required to make it work.

Just my $.02...

[Swedish Mike]

Well as far as sequential fuel injection is concerned, I don't really see any performance benifits of it. I can see the benifit of sequential timing if you're running the motor in a high rev sitation where your charge time for the coils is at minimum.

As Dash said, Crank or cam only timing has been around for a long time and works quite well. If the cam timing is out, do you want the spark timing to not change? I wouldn't think so. And considering the computing speeds the ECU's are capable of today, do you really think you can spin a motor so fast that the ECU can't time the spark events reliably? If it IS turning that fast, then I doubt this is a street motor. Wait, there ARE street motors that turn that fast, they're sport bikes and I'm pretty darn sure they don't use both cam and crank signals.

I'm not saying it's a bad idea, I just think it's superflous, and has little gain for the energy required to make it work.

Just my $.02...

But if you got an EMS with the option to control seq ignition and injection, why not use that? The engines runs smoother and no extra fuel/spark waste.Only a sensor away if you got a EMS ready for it.

And this thread was meant to discuss sensor locations, not if you guys like to run seq or not!

[dattodude]

Whatever this thread is discussing, it's the only interesting one we've had in several weeks.

I thought I was misreading you when you said you were doing both CAM and crank. I've never heard of that. As for the cam going too fast for the ECU to handle the input, that's just rubbish. Absolute rubbish.

More sensors means more expense. If you don't have spark, the engine stops. No big deal. If we were talking about something to make the valve timing more resilient, then I could 16 good reasons why that is a good idea.

Replacing the CAS is fraught with too many potential problems. It would be better (and cheaper in the longrun) to buy an ECU that supports sequential ignition and fuel with just the CAS as the input.. like I did with my Autronic. :-)

If you want to do it the hard way, that's your decision, and I'm sure someone convinced you it was a great idea, but are they gaining any financial advantage as a result of this advice?

I'm very very skeptical of the value of needing both crank and cam angle sensors. I'm definitely with float on this one.

[float_6969]

But if you got an EMS with the option to control seq ignition and injection, why not use that? The engines runs smoother and no extra fuel/spark waste.Only a sensor away if you got a EMS ready for it.

And this thread was meant to discuss sensor locations, not if you guys like to run seq or not!

I know this thread was meant to discuss sensor locations, but humor us a little! It's not like we've got anything else to talk about that isn't "repair" related!

Now, as for moving the CAS, can I ask why? What's wrong with it on the front timing cover? Are you just wanting to move it so you don' t have to remove it to set the cam timing (cam gears)? I can kinda understand that, but the CAS is only held on with 3 bolts, and setting the timing isn't that hard either. If you're wanting to move it just to be cool I can completely understand and appreciate that, but I would pose a couple of questions first. First is, by moving it to the back of the cam, wouldn't it be spinning backwards? Will the CAS still work and give time properly? Second is there enough room? Last is that I would think you'd have to permanently modify the camshaft to make it work. If you ever change cams in the future you'll have to have the work repeated.

As I stated before, I have absolutely no issues with sequential ignition timing. I think there are no negative downsides to it whatsoever. I DO have issues with sequential injector (fuel) timing. My problem with it is that since you are only firing the injector when the valve is open, you have to run much larger injectors (or high fuel pressure) to get enough fuel in. Where as if you run batched injection, you literally have twice the amount of time (maybe more) to inject fuel. This allows you to run smaller injectors (normal fuel pressures). The sequential injection DOES make the motor run smoother at idle and low load, low RPM conditions. But I run SDS w/batch injection and timing only and have had multipe people comment on how stable my idle is. If there is a way to turn the sequential injection off at a certain rpm/load combo then I think it would be OK to at least try and hook it up.

From my EXPERIENCE, batch fired injection isn't that bad at all, and batch fired ignition timing hasn't posed any problems for me so far. I'm only running up to 7500 RPM and making 270HP to the wheels at best right now, so I'm not really trying the systems abilities either.

[Swedish Mike]

Whatever this thread is discussing, it's the only interesting one we've had in several weeks.

I thought I was misreading you when you said you were doing both CAM and crank. I've never heard of that. As for the cam going too fast for the ECU to handle the input, that's just rubbish. Absolute rubbish.

More sensors means more expense. If you don't have spark, the engine stops. No big deal. If we were talking about something to make the valve timing more resilient, then I could 16 good reasons why that is a good idea.

Replacing the CAS is fraught with too many potential problems. It would be better (and cheaper in the longrun) to buy an ECU that supports sequential ignition and fuel with just the CAS as the input.. like I did with my Autronic. :-)

If you want to do it the hard way, that's your decision, and I'm sure someone convinced you it was a great idea, but are they gaining any financial advantage as a result of this advice?

I'm very very skeptical of the value of needing both crank and cam angle sensors. I'm definitely with float on this one.

As I wrote before, I got major problems to talk technical English....The cam´s wont go too fast for the ECU but you need to trig the cam location to run seq.The ECU can´t tell what part of the cycle you´re in without it, the reason is 2 crank revs per 1 cam rev.Hard to explain, nevermind.

I´ve used crank + cam sensor in both Autronic, Motec, Nira and AEM.Also seen this in all new cars, stock in Bosch controlled cars since early 90´s.

You can use the same sensor type on both crank and cam, the Bosch one cost around 20 USD.I would rather go new Bosch sensors than an old CAS from 91.

Have you guys seen any engines running seq without cam sensor? If yes, please help me find some info. I can only tell you how it´s done here, all inputs are nice.

float: I want new and fresh parts, easy and cheap to replace if something brakes.That´s why I love Bosch, good quality and easy to find.

And I agree, I don´t NEED to go seq but all the engine tuners I´ve talked to prefer it and want me to use it if the EMS can handle it.Besides that, all high power engines here run seq, normal over here.
Modified by Swedish Mike at 8:37 AM 12/27/2006

[Swedish Mike]

From Nira´s site ->

"Since NIRA i3+ is operating fully sequentially, a signal that indicates the position of the cam shaft is needed when the engine is started. That way, NIRA i3+ can determine the phase of the combustion cycle. NIRA i3+ is versatile and takes signals from both hall and inductive sensors as input."

From Motec´s site ->

"Sequential means that each injector for each cylinder is triggered only one time during the engine's cycle. Typically the injector is triggered only during the intake stroke. True sequential injection requires the ECU to know not only where top dead center is, but also which half of the cycle the engine is on. TDC on a 4 stroke occurs 2 times during the cycle, once on compression and once on exhaust. MoTeC references all timing events that occur within the ECU, to Top Dead Center Compression. This generally requires an input on the engine's camshaft to provide the ECU with a SYNC signal. Once the ECU is synched, injection timing can be optimized to provide the most efficient mixing of fuel and air into the cylinder. Control of injection timing can lead to increases in midrange torque while decreasing emissions and fuel consumption."

This is why I need the cam sensor.

[float_6969]

I completely agree with the need for a cam sensor for sequential injection/ignition. You'll get no argument from me there. That is the reason Nissan uses a cam angle sensor, it's the only way to tell where the motor really is at in it's combustion cycle.

I don't understand why you need both the crank and cam inputs for the ECU. That just seems horribly redundant, and a waste of time and energy. The CAS can not only tell you if you are at TDC, but on which part of the cycle.

Can you give me a link to the sites in English so I can read up on them? I'd be very interested to see what reasoning they have behind needing both.

Also, the quote that you posted from Nira's site may be confusing you. To me it sounds like it's just able to accept two different kinds of input, not that it needs both kinds of input for sequential injection.

[float_6969]

Take a look at this, just to humor me please!http://www.sdsefi.com/techseq.htm

[Swedish Mike]

I completely agree with the need for a cam sensor for sequential injection/ignition. You'll get no argument from me there. That is the reason Nissan uses a cam angle sensor, it's the only way to tell where the motor really is at in it's combustion cycle.

I don't understand why you need both the crank and cam inputs for the ECU. That just seems horribly redundant, and a waste of time and energy. The CAS can not only tell you if you are at TDC, but on which part of the cycle.

Can you give me a link to the sites in English so I can read up on them? I'd be very interested to see what reasoning they have behind needing both.

Also, the quote that you posted from Nira's site may be confusing you. To me it sounds like it's just able to accept two different kinds of input, not that it needs both kinds of input for sequential injection.

I only copied the cam sensor text, they had another one for crank sensor, same with Motec. You need both but I copied the cam part just to proof I´m not BS:ing you...

You need both cause the crank sensor is the main one, the cam sensor only help the EMS when you start the engine. After that the crank sensor works alone.If I recall correctly you also needed the cam sensor for ALS and some other toy functions.

Some info from Motec regarding Batch Fire ->

"Batch Fire - Batch fire means that 2 or more injectors are triggered at the same time once every crankshaft revolution. If the ECU is synched with the engine's cycle, the injection timing can only be half optimized as fuel is injected both on the intake stroke and on the power stroke. Companion cylinders are paired in batch fire mode similar to wasted spark ignition modes. The advantage of batch firing is that the ECU needs only to know where TDC is. This means that a sync on the cam is not required. The disadvantage to batch firing is that the Injector Dead Time is doubled for the engine's cycle. This leads to a decrease in fuel flow and typically requires a larger, less efficient injector to be used to make up for the loss of flow. On High Horsepower applications this means the idle quality will suffer tremendously."

[float_6969]

LOL, I'm looking at motec's site as we speak and I just read that.

I can tell you that Boost-Boy (Dee) using SDS (batch fired injection) has run pretty large injectors on a CA18DET (stock bore diameter and crank) w/o any idle problems. I want to say they were close to 1000cc's. maybe 750's, I can't remember exactly.

I guess what I'm getting at is that I question a system that needs both crank and cam input. The cam input tells you everything you need to know. As I said before, the crank sensor is redundant if you've got a cam sensor.

As for gas mileage on batch fired, I can tell your from EXPERIENCE that it still gets great mileage.

Example: Yesterday I put about 280 miles on my car. All on the highway. I just filled it back up this morning and put a little over 9 gallons of gas in it. That's about 30MPG.

Last time I checked 30MPG, wasn't anything to scoff at for a 270whp 1.8L I4. And that is all due to the standalone. I NEVER came anywhere NEAR 30MPG with the stock ECU. Maybe 27MPG on a good day. And the worse I've ever seen on my car was 20MPG. That was beating on it all the time when I first got it.

As I said before, sequential injection isn't a bad thing, especially for the ignition. It just seems like a lot of work to have to hook up a crank AND cam angle sensor.

[float_6969]

Oh wait, I missed the dead time part of that. I have an issue with that statement as well.

Yes, it's true that the total dead time per cycle is increased because you are firing the injector twice as often. What I DON'T agree with is the need to use a larger injector to compensate for that. One of the BENIFITS of batch injection is that you can use a smaller injector than what you could use on sequential injection because you able to fire the injector when the valve isn't open. This means you have much more TIME to inject the fuel needed per cycle.

So yes, the dead time is doubled, but the time that you have to inject the fuel is double, and actually it's more than doubled.

Here is a quote from that page I just linked you;"Sequential Injection Realities

We receive many calls and enquiries about whether our system offers sequential injection. Many people asking this question don't even know what this is but they insist that they must have it.

Timed vs. Batch

Sequential is a bit of a misnomer. Technically, all EFI systems are sequential in that once all cylinders have been injected, the sequence starts from the beginning again. A better term would be timed, implying that the starting and finishing of the injection pulse is timed with the intake valve opening. The idea behind this is to spray fuel only when airflow in the intake runner is established. This is supposed to mix fuel and air better and reduce manifold wall wetting. The other injection strategy is batch fired where several injectors are triggered simultaneously and not timed to the intake valve open period. In effect, the fuel sits in the runner for a short period of time before the valve opens and the airflow carries the mixture into the cylinder. Some people are dismayed that anyone would use the batch fired method however, there were tens of millions of Bosch and Bosch derivative systems sold in the '60s, '70s, and '80s which worked just fine using batch firing. It is a very well proven concept indeed. The SDS is also a batch fired system. The timed concept was developed mainly for tougher emission laws and EPA cycle testing where much of the cycle is run at low rpm and part throttle, where the time available to inject is long and the injector pulse is short.

Performance Applications

Performance applications are somewhat different from stock applications. Rpms are generally much higher, fuel flow rates are much higher and emissions usually take a back seat to power output. As rpm increases, the amount of time available to inject the fuel decreases. This is true whether the system is timed to valve opening or batch fired. The batch fired system has the advantage of being able to inject fuel for the entire period of crankshaft rotation whereas the timed system technically only has the time available that the air is flowing in the intake runner. This is determined mainly by the camshaft characteristics. On an average performance cam having 220 degrees of intake duration measured at .050 valve lift, the sequential system has only 61% of the time to inject the fuel as the batch fired system. As such, true, timed, sequential systems must have larger injectors fitted for a given hp. It should be remembered that there is little airflow and velocity in the port and runner until the valve is open a fairly significant amount. Starting the injection sequence early and finishing late, partially negates the supposed advantages of timed injection. On a high revving engine, there are only a few milliseconds available to inject before the next cycle begins. On the other side of the coin, with batch fired injection, the amount of time that the fuel sits in the port shortens as rpm increases. In the end, there are no significant differences in top end, wide open throttle, horsepower between batch fired and timed systems. We have also not seen any significant differences in fuel economy between the two strategies. Emissions at part throttle are likely to be better with timed injection as this is what it was developed for. On performance applications, emissions are often not an issue and most engines not equipped with a catalyst will not pass a modern emissions standard anyway.

Complication and Expense

Batch fired EFI systems are far less complicated from a software and hardware standpoint so it stands to reason that they will be less expensive to purchase and easier to program. Timed systems require camshaft timing information for the ECU either derived from a camshaft sensor or a multiple input signal from the crankshaft sensor. Timed systems also require a drive transistor for each injector, a separate trigger wire for each injector, cam timing specs, injector response time specs, cylinder firing order and the software to process the information. The person programming also requires a lot more knowledge on how all these aspects inter-relate to each other and the wiring for the injectors becomes much more complicated. If any of these steps are omitted or misunderstood, the timed system is no longer timed. Additionally, there are some aspects about intake port flow that very few people would have a clue about. You'd really be taking a bunch of guesses about when to start injecting and stop injecting the fuel. Is all this worth the trouble on the average performance/race application for little or no gain in hp? Would YOU understand how to hook up and program a sequential/timed system? I think those questions have already been answered. The batch fired system merely requires a tach frequency. Generally, for each ignition pulse, there is a fuel pulse. There are less wires to run and no complicated timing software to figure out. Very simple and it works very well."

[Swedish Mike]

This is like religion, they all got their favorite...

If SDS ran seq they would write that seq rocks and if Motec ran batch they would do the same.

My two reasons for running seq is this: All the big EMS´s recommend it/use it and all the engine tuners I´ve talked to recommend it.That´s all I need!

I know batch works fine, it´s used for years but I don´t really care if batch beat seq in every way. I follow my engine tuners advice and he´s never been wrong before.

My god, I´m defending seq injection in the worst CAS thread ever!

[float_6969]

LOL, I don't want you to think that I don't like sequential injection. I just don't want other people to think that batch injection is this awful archaic technology like Throttle body injection or something.

[Bwana]

I'd mount the sensor on the front Mike.

[Swedish Mike]

I'd mount the sensor on the front Mike.

Haha, fuuuuuny!

I actually thought about it, I only need one trigger pin, easy to mount on/behind the cam gear.

float: I understand. I don´t think people in general hate batch.I relate the EMS price to the engine price, if I´m building an expensive and crazy engine I rather use an expensive brand EMS. Don´t know why but feels safer and more knowledge around.

My buddy used a batch DTA EMS up to 400 bhp and swapped to a Nira after rebuilding the engine.The engine tuner wanted to control things more accurate, I think this is pretty common, at least here.

[dash]

Swedish Mikeits all good man.... run both cam/crank since you're sold on it.It will be good to compare notes when done.... not on paper. Will it set any benchmarks ? It'll be awfully hard imo, but we'll see.I just say its a little far fetched to call excellent performing motors a 'bad idea'.... you'll have a difficult time quantifyng that. lol

[Swedish Mike]

Swedish Mikeits all good man.... run both cam/crank since you're sold on it.It will be good to compare notes when done.... not on paper. Will it set any benchmarks ? It'll be awfully hard imo, but we'll see.I just say its a little far fetched to call excellent performing motors a 'bad idea'.... you'll have a difficult time quantifyng that. lol

I really think it´s a bad idea to use one sensor when you got a EMS ready to use two.If I ran batch I would use one and stay happy using one.

Compare notes? Compare to the most powerful batch EMS CA in the world?Doesn´t matter if I ran 400 or 600 hp, would use my EMS and seq anyway.