want to change Cam to EFI Friendly

I run this currently
S1 Cam from Indy solid flat tappet
260/266 - .558/.555 1.5 Rocker and 108 degree lobe separation.

What would be a good change out to a street strip friendly EFI cam for my 415 Small Block.

I run a 5k stall if that matters

I am looking for something that is not so Choppy.

What I have now is OK but not to friendly on the vacuum side for the efi.

I am not sure what direction to go I don't want to loose to much performance but a nice smooth idle would be awesome

EFI doesnt like narrow LSA cams... as in 108... will they
work.. yes.. I have a 105 LSA cam in mine installed at 105
but that gives a good amount of overlap... a wide LSA drops
the overlap to give a smoother idle

I can design you a cam.
Cubic inches, what heads, compression ratio, induction details, if racecar what ET, cars weight, transmission, what EFI system.

The right efi/ tuner can make any cam run evenly. Any efi system with a blending capability of map/tps will idle at very even cadence. No real need to swap cams if you are happy with it.

have to go with open loop idle since map signal will be erratic. Ive been playing with that myself lately on my Gen III and have learned a lot.

When the idle map values go inverse, start substituting tps voltage. The reason you need to go open loop at idle in some situations, is that the exhaust gas is inconsistent in oxygen content. Lambda sensor is "seeing" overlap(high O2), and than blasts of low O2 from combustion. There are a lot of ways to overcome these issues with the right system configuration.

EFI don't care what cam you have, only a bad tuner blames the cam.
I run solid rollers, 280 at .050, and .750 lift

Even according to the techs at the different EFI companys they
all said that the wider LSA is better... that way you dont need
the electronics to try to cover up.. but the narrow cams will
work... on my Holley.. it changes loops at 160* so that is a while
even with a stat(I have 4 1/8" holes in the stat to move water at
all times due to the elec pump)

EFI essentially eliminates the need/effectiveness of fifth cycle scavenging during the overlap, since the fuel is pressurized (rather than drawn) the injector can deliver the fuel (as well or better )later in the induction opening cycle, that also gives you more room for Air (read:Oxygen) to get in the hole and still get the fuel in before the slug turns around at BDC and the compression cycle starts.

Bottom line is when you spread the lobe centers and (generally) delay the ICL the torque curve broadens and particularly part throttle drivability increases compared to a carb. But at WOT it's tough to significantly top a well-tuned Holley when using a conventional single carb/EFI TB intake induction system. You basically tune the cam timing to enhance part throttle drivability. Direct Port injection is usually a different animal though. Those have the advantage of the runner building AIR velocity and don't have to worry about suspending emulsified fuel with it most of the way.

P-Body is correct, wider LSA is better, but if your EFI system can do it, you can dial in a radical cam by sequentially not starting the idle injection pulse until intake reversion is over, and by programming the idle area in Alpha-N (TPS as was stated above). But in order to do any of this I'd need to know what EFI system it is. If it's a no-laptop hands-off system then you have to have a more friendly cam with a wider LSA.

I am running a Comp XS282S with a self tuned and built Megasquirt system (MS3X) and it idles and drives great!

PID Tuned closed loop idle as well. I have the ICV Valve set for 1000 RPM target, and it does a good job of keeping it there no matter the load.

FASTMo your probly right. I am new with EFI and forgive anyone that is trying to learn anything new. I am asking the question because I don't know, and from the look of your response you don't either so next time don't comment on what you don't know. and if you do know you are a [censored] teacher.

thank you everyone else and please keep the advise coming.

You bet-cha !

I have an IAC motor and so far have had to keep it closed and off to have consistent idle with my MS3'd Gen III Hemi. I don't even know what the PID is and the Algorithm for IAC is either always moving or always on and neither makes sense to me. I have good clean idle once it warms up but have not figured out a good warm up mode/cold start setup and I know I will need the IAC for that.

While you may have taken it the wrong way, FastmOP was exactly right. With a well tuned EFI, the cam is of no consequence. And some also claim you have to Alpha-N to make cars with radical cams idle..........I don't. I run everything in Speed Density and have never had a problem. Also getting the injector end angle numbers correct is important on a sequential system. You don't want the injector spraying on the backside of a closed intake valve

Monte

The idea of going wide on LSA to get a decent running motor with EFI just doesn't sound right to me. When did the laws of physics change and ram tuning go away with EFI? From what I have learned, overlap and LSA are dependent on how well a motor breathes at overlap. Better breathing, wider LSA. Poor breathing, narrow LSA. The air doesn't care where the fuel comes from, or how. Examples- Gen3 Hemi, VERY good overlap flow, ,wide LSA. Any four valve per cylinder motor, excellent overlap flow, wide LSA. 440 with stock heads, not so good. Narrow LSA. Smallblock stroker, poor overlap flow, narrow LSA. One last comment- I don't hear of racers changing LSA when going from carbs to constant flow injection, so that rules out any ideas about vacuum signal.
EDIT: Mike, your comment about the EFI engineers saying you won't need electronics to cover up a narrow LSA, it sounds to me like their systems aren't flexible enough to adapt to the right LSA for a radical motor??
So my question for the OPs situation is, what is the best, mnost flexable EFI system that will work for the best cam for what he wants? That way he won't have to crutch anything to get a sweet running package. My interest here is similar, I have a dragpak cam with a narrow 110LSA, and plan on EFI with Apache heads on a Gen 3.

You'll have to forgive my somewhat dated suggestions. I've been screwing around with this stuff since the dark ages, on a wide range of systems. The tps substitution (at idle)is the method I prefer, because I'm familiar with it, and it works well for me.
I believe it was Motorola(?) that came up with engine position map sampling that allowed early efi on Harley Davidson engines to use 100% speed density on a very poor map signal engine to run evenly and consistently. These systems were programed to use a narrow window of map signal in a determined engine position(where the map signal was consistent and strong)and ignore the rest of the map output.
I admit that my exposure to more modern efi systems is limited. Is the holley system capable of adjustable map sampling?

This is thread is a great example of why you should buy the system that the tuner you will be using recommends. Everybody here has their reasons based on past experience.

My last post guys...

Monte: I believe you like Holley EFI, and I tuned FAST for 10 years. Well, I just became a Holley EFI certified dealer and spent an entire week at Holley (3 diplomas :^)) I have wanted to run alpha-N at idle for years but FAST can't automatically switch back to Speed Density - but Holley CAN! It's the Holley-preferred tuning technique for radically cammed motors that want to be driven on the street. I will explain the technical reasons in a paper that will soon be posted on my Technical Info page.

I have tuned many race engines including several blown alcohol and turbo motors and I have always used only Speed Density. No issues. But I wasn't concerned about the low end drivability. Start - stage - WOT. Controlling the injection end angle is a critical part of the equation which tuners will use if their system can do it (both Holley and FAST can).

Gregs: The laws of physics are the same, but EFI can use the capabilities a little bit better. On my dyno I tuned race motors with carburetors and produced good power. After those engines were converted to a smart EFI system I made about the same max power but I was able to tame the idle a bit using the above techniques with no cam change. In a race motor you design the cam for the engine/head combo and then tune as required.

Trendz: Yes

A wide LSA cam is a way for an EFI system that cannot do these things to run better on the street simply because idle is better. Its not much more complicated than that.

Rich, I follow what you are saying, and that is what I figured. I think there would be a small loss of upper mid range and top end power, because the LSA is wider than ideal, shortening needed overlap duration.

Right on!

Drivability for radical cars works just as well with Speed Density. Holley has no "preferred" way, but the box is capable of doing it any way the tuner chooses to do so. That being Alpha-N, Speed Density or a combination of the two. We have had no issues making Speed Density tuned cars drive quite well on the street and have done so with several Drag Week cars. Now while Alpha-N might be "easier" for a novice tuner, the other method works just as well once the tune is sorted out.

Now Holley may "suggest" certain things, because they know it will make it easier for the average tuner to deal with and therefore cut down on tech calls.........but, either way works. The engineer who designed the system at Holley, just took his pump gas Drag Week motor off the dyno. It made over 900Hp and will be going in his car for this years Drag Week. It is tuned in Speed Density

Monte

Why is it that all the car companies went to the wide
LSA cams shortly after we went to injection... I am sure
there is a logical reason... if they wanted to cover up
the idle with the electronics they wouldnt have wasted all
that money going to the wide LSA cams

Comp has a whole line of cams called the XFI. When I flip thru the catalog it looks like almost every single XFI cam has an LCA of 113. I'm guessing that there is a reason for it.

Like Streetwize already said.........you don't NEED a lot of overlap with EFI because the fuel delivery system is way more efficient, heads are better, EVERYTHING is better these days. How many stock and super stock guys you see now running 102 LSA cams like used to be common. Things change, we are smarter and realize you don't have to crutch the motor with a poor cam design. So they are not trying to COVER UP anything. They are using what works BETTER for both idle quality AND power. That still doesn't change the discussion here and that is with PROPER tuning, the ECU doesn't care about the cam. You can MAKE it work

I suspect the main reason for a wide LSA for OEM is emissions related. The more overlap, the more time there is for unburned hydrocarbons to find their way into the exhaust, either thru reversion or low rpm misfire.

On my Commander 950 Pro TBI, I went A/N to 1800 RPM to get the idle to behave with an MP509 cam. Depending on the weather, closed loop it would chase the target AFR until it quit. At idle 76 deg of overlap misses a bunch. Every time it misfired, the ECM saw that as a lean condition (no fire, all the O2 in the cylinder goes in the exhaust) and just kept adding fuel until it loaded up and quit. Unless of course the cause of the misfire was a lung full of reversion exhaust which the ECM reads as pig rich (no O2) and cuts the fuel for next time. The end result is the same, the ECM chases it's tail until the engine just quits.

We could have set it to run open loop but as I recall the fuel map resolution wasn't good enough to make that work very well. If the new Holley systems have more resolution, this is likely an option but I don't see that it is much different than A/N when all is said and done.

Kevin

I understand that you can inject the fuel at the last given moment
to help correct... but the valve is still doing the same thing...
if the O2 thinks its seeing a lean condition the next cycle will
have more fuel applied.. so in reality its chasing the last cycle
but if the overlap is minimal then it wouldnt be.... JMO... I'm
still having idle problems of going fat(before I pulled the engine
the last time)... maybe I just have the idle set to low based on what
some are showing... I figured 850-900 would be a real number... but
I also have to get the temp up higher for this to learn... above
about 1300 things come around... this is on a 105 LSA installed
at the same thing
EDIT
it could be as simple as to cold of plugs.. 3923... this time
I'm going to 3924

my car now seams to be happier with a higher idle as well. I started out at 1000rpm after its good and warm it is around 1250 to 1300. it doesn't really bother me but I really am just looking for something that is just a little more street friendly.

I am really new to this EFU stuff and I really like it, I guess I will have to do more reading and chatting on tech pages. I can make it idle much better the more I learn. I somewhat understand what everyone is saying I just need to learn all the lingo.

I Apologize for my comments, I may have taken the comment incorrectly, I'm Human. just for clarity I wasn't blaming my cam for the car not doing what I want it to I was just looking for something more efi friendly. I will do my research with comp cams this fall and maybe I will do a swap if needed.

where do I want to make my AFR targets?

again thanks a million for all the discussions

Until this last post, I honestly didn't realize you had an efi setup on the car. I thought you were thinking of going efi, and planning on changing the cam to do it.
What system do you have on the car? With that info, I'm sure you can be guided to get the engine running more as you desire.(assuming the system has the capabilities) As stated previously, some systems are limited, and you may need to make a choice between changing the cam, or ecu, depending on what you have.

I too were under the impression you were looking at EFI not a user already. What system do you have? It will help narrow down what's needed.

My suggestion, as a novice tuner, would be to turn off your O2 feedback, get the car to idle, then move spark timing to get the best(lowest) map value. Then, do the same with fuel. Once both of those are done to achieve the lowest map value, look at the O2 reading. This reading is the value that the engine likes at idle. Set your a/f table to that value. After that is done put the ecu back into closed loop.
Again, we need the system and options.

Excellent advice^^^^^^^^!!!! I need to do it myself actually.

I have on the car EZ EFI 1.0. I really do like the system it may not have all the bells and whistles as the 2.0 but in the next month or so I can upgrade my software to get me closer to the 2.0 options.

So I have the EZ EI 1.0.

I have a some time to return the 1.0 if I want and upgrade to the 2.0 but I don't think I need the 2.0.

The 1.0 definitely doesn't like a weak vacuum signal. Might be a way to trick it into running better though. Also found that my car ran best with the WOT set to 11.8 when I had one of those.

I would say you need to change your cam if you're not tuning your efi with a laptop. I don't know enough about those systems to confirm this, but maybe others here have.
When you are effectively "locked out" of any part of the tuning, you will be limited to what you can achieve. Sorry.

I would like to see you go to the 2.0
If you don't then a cam change and loss of power may result.
I'm not sure what a 1.0 is capable of.

The EZ is not the greatest choice. You are locked out of the ECU and can do no personal tuning, as other similarly priced systems allow you to do.

EFI is great and I am a BIG supporter of it, but DON'T buy a system you can't tune. As stated, other systems that cost essentially the same as the EZ can be tuned with a laptop OR let the box does it's thing only, but at least you have the choice

Here's what MSD says about cams with their Atomic EFI:

"If lobe separation angle (LSA) is less than 108° you may need to go to the next larger cam profile. If cam duration is longer than 250° (@ .050" lift) the Atomic EFI will not be suitable for your application."

Okay. Last week I said I posted my last post, but finally kiddart answered the question - what EFI system do you have. I have to respond now because I support both FAST and Holley. Neither the EZ-1 or the EZ-2 is a good choice for an engine with low idle vacuum. I agree with Monte - you should have a system that at least lets you connect with a laptop if you need to. The upgrade that Kiddart is referring to is a change in the hand-held, but you still cannot link with a laptop.

A common band aid when an engine is near the edge of too low a vacuum is to advance the intial timing. Going up to 20 or 22 initial might make the difference.