Just a quick question...

When tuning cams, what exactly is adjusted to correct the idle?

more specifically, is it the VE table that would effect idle quality? I would assume that some fuel adjustments at idle would smooth this out, is that correct?

 

Good question. I want an answer to this too.

 

its in ur pw

 

que?

 

Couple of different things depending on how "wild" your cams are.

Biggest thing is your maf calibration at your lowest cells. Turbulence seems to play with the lowest two maf cells, easily corrected.

You also might have to add a bit of timing at idle I find if you have an electronic throttle body, and at coast down if you can.

 

ahhhh MAF, that makes sense

was just curious...so both of those should be able to be taken care of with the SMT-7 for example.

 

x2???

 

With very street friendly cams you can fuel properly with the SMT. In all reality, I bet it comes out being pretty accurate with the stock tune. Anything wilder than what the stock ECM can handle will probably cause you idle and coastdown problems.

Things you won't be able to do:

Adjust idle. Welcome to electronic throttle bodies.
Adjust rev limiter.
Soften up misfire detection. You will be stuck with a p0300 code if you have too much crank jerk at idle.
Adjust or eliminate any throttle checks. Again because of the electronic throttle body. You may be able to skew map slightly to match maf by failing (removing) the maf and hoping the car fuels and trims correctly then correcting out trims to 0 with the smt. I honestly don't know how well this will work. Every car I've piggybacked has been a speed density one with a cable driven throttle. With no IAT sensor, this might fail.

All I can think of off the top of my head.

 

so what ur saying is bc we have the electronic tb there's alot we can't adjust. how is idle adjusted for f/i cars? i've always hated the fact that we have electronic tb. so basically in a nut-shell, u CAN tune cams but ur limited in what u can tune? also, what do u mean by street friendly?

these?
http://www.turbotechracing.com/produ...idproduct=2450

 

You think so? I was thinking of running the Comp Stage 1 cams since there isn't a way to bump the rev limiter other than standalone. Actually I have been looking at a piggyback fuel tuner called the FT40 by Perfect Power that claims they can "extend" the RPM limiter...bascially making my new rev limit at whatever RPM the ignition cut is at.

with these cams though it sounds like most of this stuff wont be a concern and I'll only need small adjustments and be on my way.

 

I've done it on emanage with a fuel cut by simply taking over injector PW completely. Only works on some cars and they are obd0 or 1.

I'm pretty sure the L61 ECM uses a fuel cut limiter. Earlier alpha-n based cavaliers MIGHT have used a spark one but I'm not sure.

 

Jerry,

Most ecotec cams can get by even without tuning. They don't really increase lift much, just extend duration for the most part. Thos cams are easier to tune. Just calibrate your MAF (really easy on non 2.2L with HPT). There is no other tuning really required on your MAF equipped car even under WOT. as long as you get the MAF tuned right everything else should fall into place.

 

yeah I know the 2.2L cuts fuel for the rev limit but isn't there a spark cut shortly after that?

I know an option is having the fuel injectors controlled completely by standalone but I didn't know if I really wanted to go there with this car so hopefully I can get what I want out of a piggyback unit.

I feel less afraid to jump into a set of cams now based on the info you guys have posted, thanx! now i just gotta get reading on tuning the MAF...

 

ioninja, i thought u were going to turbo your car?? if so comp cams make a turbo cam to as well as supercharger.. as you already no they make stages 1-3.. i was worried about tuning to, but after reading your thread about it, not as much.. also there is a e manage ultimate that has something to do with the limitor for our cars.. check it out.. i have a thread in tuning for it, talks all about it from there site

 

WITT
My cam specs are Intake: 264 deg lift: .417
Exhaust: 260 deg lift: .408
Would that explain the PO300 I get every once in a while at idle? Will this cam make tuning MAF more difficult?

 

Definetly should not have a problem. GM MAFs are very forgiving in my experiences with wild cams.

If you have an ss/sc youll have a chance to add some idle and coastdown timing to help the electronic TB maintain proper idle and coastdown.

If you ae getting a P0300 use hptuners to soften up you misfire detection during slower engine speeds.

 

^^^ Thanks

 

im still very confused by all of this. if someone could relate to me in a laymens terms i'd b very appreciative. what is pw? and witt u confused me by saying wild cams wouldn't b tunable, n then the gm maf is forgiving with wild cams. i'm trying to understand my car and increase my knowledge. i tried doing research on my own however, it all flies over my head. PLEASE HELP!

i think im gonna just get stage 1 n say **** it! lol.

 

Theres more to tuning the PCM for them other than MAF. The above poster asked me if the MAF would be easy to tune. By his user name, I'm guessing he has an SS with HPTuners or EFILive support. It is easy as the MAF can be recalibrated, timing added where needed and rev limiter and idle limits adjusted.

With a piggyback you won't be able to take full advantage of the cams if they are wild and you will be stuck with a check engine light and a poor idle at best, an unusable powerband at worst.

pw=pulse width.
When talking about fuel injectors, its the length of time they are "powered" to fire fuel into the head, intake manifold, or combustion chamber.

When using the term pulse width with anything other than injectors, its a term used to describe a repetitive pulse of power to achieve a desired speed, pressure, or torque such as a cooling fan or fuel pump.

 

me turbo? no not this car, I am nitrous all the way. just installed a mount for my 2nd bottle in my trunk not too long ago actually...

I do plan to turbocharge another car hopefully this year but thats another story.

I have some goals I want to finish with this car first though which is cams & a tune and 13's

 

thats cool man, good to hear.. 2nd bottle?? woohoo, thats a lot of nitrous.. i was looking at the comp cams turbo and was wondering if my 2.2 would except them well with a slight tune or so with my upcoming turbo.. i no after i get the turbo in, i want to put the comp cams in turbo edition ones.. dont no if they are wild, they dont seem it, seem to be more of a moderate.. what do yall think?? doesnt say anything about needing tuning much like the stage 2 and up does

ion, did you forge up the motor at all yet?? also you got any pics with the 2nd bottle in there..

 

Jerry,

Not sure how you plan to tune the MAF, but look for something that can help you tweak it.

 

I was originally looking to go with the FT40 but looking at the features I don't see any mention of MAF adjustments.

Looks like the SMT7 would be my only choice there unless I missed something...or the AEM FIC.

Cobalt4Life, I looked at the specs of the comp turbo cams and I don't really understand them...based off the lift and duration specs they seem to be less aggressive than the Stage 1's? i know yellowshowbalt is running the blower version and said they are fine, he only has issues with his idle going between 800-1000RPMs every 15 seconds or so but they drive fine.

oh and bottom end is bone stock and yeah I have pictures of my trunk setup, will post them soon.

 

what exactly should be expected from a new cam? the pro and cons of using one. also should you work on the internals b4 installing these?

 

Either one will do it, just somewhat differently.

The SMT will do it directly since its compatible with digital MAFs, the AEM won't. With the AEM you have to tune it via o2 feedback. Someone wrote a writeup here saying he was adjusting the MAF directly with the AEM FIC but AEM and the software version I have specifically states its analog only.