Help With Cammed L67

[Jayme]

Hi, im after some people with experience tuning l67's to help with this, im really inexpericned when it comes to MAF tuning. My mates L67 has got a Comp Cams stage 2 cam specs: * 212°/224° at .050", Intake Lift .325" (.520" lift at 1.6:1 rocker ratio), Exhaust Lift .335" (.536" lift at 1.6:1 rocker ratio), 116 LSA, a w2a cooler plate, 70mm tb, bored out 74mm MAF and 14psi pulley. now I havent actually started tuning this new setup yet, I wanted to get some advice before I started.

just after firing it up on the new cam today it is super rich and fouling plugs. now that is normal for a MAP based ECU thats just had a cam installed, but it goes against what I understand of MAF's, id imagine it should be metering the incoming air and putting in the right amount of fuel, unless its double metering some air due to reversion?
anyway, has anyone tuned a setup like this? im not after help looking over logs and actually doing the tuning, what im after is:

• if anyone has tuned a MAF L67 with a cam, is it normal to have this super over fuelling at idle when using the stock fuelling and why?
• what tables do you usually look at modifying to get a setup like this right
• is anyone willing to share a bin of a cammed L67 for me to see whats been changed from stock to give me a bit of a head start

[ejukated]

Do you have bigger injectors too? the running rich might be also because the maf is all out of wack from being bored. Last cammed A2A i did i just fixed the injector rate for the new injectors and it fired and idle reasonable. Coasting and 3 point turn type stuff needed abit of work but it definatly idled ok no load. In all honesty id just go standard ls1 maf or l98 maf (85mm) but the idle air might be abit low for it to read properly around idle conditions

[Jayme]

injectors still stock. id already redone the MAF tables for the 74mm maf when it had the standard cam. so the only thing that changed between when it was good and now is the cam and cooler. its missing bad under load atm so my mate is looking into plugs and coil problems.

if we go any further with mods im seriously consideing just going back to 808 and $12P... its so much easier to tune lol.

[ejukated]

lol maf isnt that bad once you know how

hows the injector time, airflow, mafhz trace look in the graph screen?

[Jayme]

well id post up the log but theres not much point at this time, he used VL400's logger to log it on the way back home fromt he workshop and dropped the log off to me just now. it had a bad miss earlier in the day and he changed the module to fix it and now ont he drive home, its lost about half its power, seriously gutless. the log shows a DTC set bvut the DTC codes are not in mode1 message0 so ill have to go over to his house and do a laptop log with the DTC frame to see which code it is. th elog also shows the spark under load someitmes sitting on 0 and negative numbers a lot so bets are on that its EST realted DTC code. ill update when I know more.

[Jayme]

well, just cleared the DTC's (46 and 47) and they stayed clear, I put them down to the broken ignition module that was replaced. the knock retard is the problem. the fuelling seems not too bad now the module ahd been fixed but its picking up knock everywhere, like we were cruising at 90 k's and it was constantly hovering between 13-15 deg knock retard and had knocked back to the low octane spark map. we are confused as to how it could happen, but the motor is noisier than it used to be, perhaps its falsely picking up valve train noise as knock with this new cam and tougher springs.

[Jayme]

hehe triple post in a row. anyways, just did a quick realtime session for a bit of a test. turned off knock sensor, and fixed up the spark map up above 5500 and turned up the rev limit. its a hoot now ! it goes actually a little better than we expected. as a guide, it used to read 259 G/S on the maf with the old setup at full noise, now it reads about 322 g/s. looks like we are up for some new injectors, at 6100 rpm it hits 100% duty cycle.
ill put the wideband on it sometime tomorrow and do the fuel properly, just doing it dudgy by the narrowbands tonight. still a huge mystery why the knock sensors keep getting false knock gonna swap the sensors over and see. we are also a bit wary of the valvetrain noise at idle, might put a set of lifters in it to ease the mind.

log attached.

Cammed VX sc log.zip

(137.78 KiB) Downloaded 493 times

[ejukated]

hows the lifter preload with the new cam? if its abit low it can be noisy. also check the knock sensors are screwed into the block properly. From the log, idle looks ok. IAT is pretty good too. Looks like your well on your way to 300rwhp+

[vn5000]

Ive had issues with high lift ,long duration cams causing noisey valvetrain triggering the knock sensor before and had to disable knock sensor .With vl400s $12p i found that if i set the ignore knock counts table to around 10 in the problem areas it solves the prob ,but unfortunately you dont have that option.

[VL400]

Actually he does in the later model code bases, I didnt dream up ignore knock counts just copied the idea