This poll mainly pertains to stock CI cars, but strokers and big CI setups can chime in too.

The answers in the poll are assuming that you are tuned. I had the car tuned a few weeks back. WOT is spot on. It still needs some work at part throttle and general drivability. I need to set up a date with the tuner to tweak it a little.


I have talked to a few local H/C lt1s and the ones that have little to no cam surge are tuned with the o2s disconnected. I was planning on keeping them (thay are BRAND NEW AC's!), but I'm really frustrated with the surge at part throttle and cruising speeds. I dissconnected the o2s yesterday and it is MUCH better. It still has a little surge but I can deal with it. If my tuner can get it to drive like this with them hooked up, I'll be happy. The night that it was tuned, he told me that it's pretty much "the nature of the beast". He also told me that unhooking the o2s is an option, but a lot of people rather keep them. I was pretty dead set on keeping them as I just put brand new ones in that day, just to make sure everything was in tip top shape.

Now I'm at the point of doing whatever it takes to get the drivability spot on (or atleast as good as it is going to get).


Please list your set ups (specifically cam specs) and if you are a manual or auto!

I am not positive, but I'm guessing the the stalled auto cars do not surge as bad (or atleast it is not going to be noticed as much).

 

i noticed with mine that on the leaner side. 14.9, 15.0, etc. it had it. when i richened it up to where it stays at 14.2 to 14.4 at cruise its alot smoother. so i think thats why it does that. the o2's are constantly switching it from rich to lean and thats why you get that. just my opinion. im not an expert

 

Cam surges below 2200 rpm's.

 

assumeing your ride is 'mechanically" right (IAC & TPS counts are solid, no vacumn or exhaust leaks, etc) a "good" tuner will make it run right with 02's

....mine did.

 

I haven't adjusted the TPS/IAC yet, but so far the only surge I noticed is in reverse, you have to two foot it or it's really annoying. I'm hoping after the IAC and TPS are ajdusted it'll get beter.

 

o2 sensors don't like a lot of overlap, if your cam is that big just do OLSD

 

This is the way my tuner explained it to me.
The PCM when using the MAF and O2's, while in closed loop wants a 14.7 A/F ratio when NOT under WOT.

My car under 2000 RPM does not like that leaner ratio and has very minor surge mostly around 1.5K. It is a very mild bucking at very light throttle. The A/F ratio can be cheated a little in closed loop but the cheat will affect the entire RPM band across the board. You cant make the lower RPM's more fat than the upper bands.

With the O2's are off (open loop) or if the PCM is running in speed density mode, you can tailor that A/F ratio as needed across the board. When I run a SD tune and closed loop, there is absolutley no cam surge period.

I still choose to run the MAF closed loop tune to maximize the MPG"s as much as possible. My surge is very minor.

 

Its not that big, but does have a fairly tight 108 lobe seperation.

Is that too tight to get it smoothed out in closed loop with o2's?

 

I have a 107 LSA.
You will never totally elimminate it with a closed loop tune, all you will do is run in circles. All you can do is reduce it as much as possible with a good tune by a good tuner.