Planning on heads and cam in the future and was wondering if its possible to tune your car to pass with a big *** cam. maybe 224-230/236-240 durations and a good bit of lift dunno about the lsa yet. Just wondering what I would need to do.

 

Anyone tuned thier cars to pass emissions with a big cam?

 

Your obdi, so I assume you have to do a roller test. The 224/230 with a emmisions tune should be ok, the 230/236 maybe, 236/240, doubtful.

 

With the mods in my sig my car did not pass the treadmill without some custom tuning. I basically ran closed loop and pulled half the timing. If the cam were any bigger I think I would have had to lock it in open loop with a 16:1 afr as well.

Joe

 

damn thats not even that big of a cam... does the headwork make it harder to pass and is 16:1 dangerously lean?

 

Yeah, I thought it would be easier to pass, but perhaps the cats and the long tubes have something to do with it. I failed pretty badly on the HC's the first time I took it, but the car wasn't all that warmed up either. Taking no chances the second time, I created the emissions flash and made sure the car stayed good and warm while I waited.

I flashed my emissions tune right before I went over to the shop, but I do have a long commute and I went from work. It would be okay to run around with a lean, retarded timing program for a little while. It's a lot more dangerous to go lean at wot hi rpm than just putting around.

 

I just failed my dyno test with my cc305 (220/230 114) and an 'emmisions legal' tune...

I'm trying to figure things out now, butI could really use some pointers or an LT1 Edit bin to start with. Email me at jdove@telus.net if you have a bin, I'll also be checking the board.

HC 1.089 Max 0.50 [Fail]
CO 3.994 Max 9.32 [Pass]
NOx 0.1908 Max 1.24 [Pass]

Plugs were just done, wires are under a year old... Heads are stockers

Thanks!

 

Jason-does your exhaust run through a cat? Not having one can definitely run up the HC's... tuning it to run leaner during inspections may also help you to pass.

 

Yeah, I tossed the cat in.

Problem is I can't figure out how to lean the darn thing out. I lower my VE and nothing happens... it's driving me nuts.

 

I noticed my IAT Scale vs Airflow and Idle Air Control tables were totally out of whack. I put those (back?) to stock... I don't recall ever changing those (I had a Hypertech in my past?), I have no idea why they would be mucked with.

I 'think' it's running a little cleaner now (I pulled out some timing also, it's now about stock timing). Though my scans still show it running rich.


When I run VE Master, I get the following averages, lows and high's.

******** Fuel trim table statistics ********

Cell # recs map range rpm range
min LTerm/avg LTerm/max LTerm (left and right)

0: 0 map: 0 - 30, rpm: 0 - 900

1: 0 map: 0 - 30, rpm: 900 - 1200

2: 68 map: 0 - 30, rpm: 1200 - 2000
124/125.471/128 123/124.897/128

3: 373 map: 0 - 30, rpm: 2000 - 7000
117/120.408/128 117/121.121/128

4: 0 map: 30 - 50, rpm: 0 - 900

5: 19 map: 30 - 50, rpm: 900 - 1200
128/128/128 128/128/128

6: 3557 map: 30 - 50, rpm: 1200 - 2000
113/115.1/128 111/113.852/128

7: 930 map: 30 - 50, rpm: 2000 - 7000
110/113.813/128 110/112.155/128

8: 0 map: 50 - 80, rpm: 0 - 900

9: 80 map: 50 - 80, rpm: 900 - 1200
124/125.488/128 124/125.563/128

10: 1423 map: 50 - 80, rpm: 1200 - 2000
116/116.637/128 114/115.754/128

11: 491 map: 50 - 80, rpm: 2000 - 7000
116/118.204/128 116/118.332/128

12: 0 map: 80 - 104, rpm: 0 - 900

13: 4 map: 80 - 104, rpm: 900 - 1200
128/128/128 128/128/128

14: 86 map: 80 - 104, rpm: 1200 - 2000
119/123.198/128 119/122.895/128

15: 47 map: 80 - 104, rpm: 2000 - 7000
126/126.957/128 127/127.766/128

16: 1165 map: 41.81 - 44.5213, rpm: 968 - 1040
115/116.921/122 120/121.102/125


Which obviously I read as... rich rich rich rich rich rich... pretty much across the board.


Then again, it doesn't bottom out at 108 BLM so I might be okay for the richness, and the timing changes should help with the HC count (fingers crossed).

 

Jason,

The VE tables aren't used unless the maf malfunctions and the car reverts to speed density mode. The only way to run your car leaner than 14.7 (or what the pcm thinks is 14.7:1) is to run open loop.

But before you do that try halving the timing in the relevant areas.

Joe

 

Hehe, sometimes the easiest solution is the answer... darn evap canister. Thanks for your replies though. =)

Kinda gave it away when I pulled back timing a bit and did a 3.9 on the HC's.