What are some things to expect when having a big cam in a daily driver? What's the norm and what do you have to get use to when having one?

 

main thing is gonna be rough idle, cam surge and possible stalling

and of course the face cramps from the as you sit at a light and listen to the engine lope away

once you get big enough...the lope almost sounds like popping and cracking...hehe

 

What exactly is cam surge? My cam isnt that big (one listed in sig) but it seems somedays to be a pain when driving at low speeds and low rpms. Ive never had a cam this big so it's taking some time to get use to.

 

what you're experiencing is probably surge.

for me it happens worst at 1300-1500rpms, in any gear it seems. but only if i'm trying to hold that rpm...not accelerate through it.

the car starts to buck and almost stall.

 

Another thing I noticed is sometimes when I go to rev it up it kinda blips as is nothing is happening then it revs up. Or sometimes if I go wot for a millisecond, let off, then get back on it it bogs just a little. Ever had that?

 

Well, Idling in gear is out of the question(m6) My car would do it stock but now its out of the question. Cam surge is noticeable at low RPMs trying to hold that rpm. If I accelerate through it its fine. Cam surge is when the car starts to buck and chug and wants to stall. You wont have it that bad b/c you an a4 so your converter will soak alot of it up.

But the best part by far is watching people break there neck to see what the hell is making all of that noise at the traffic light.

 

Depending on the size of the cam, the car is going to be sluggish down low too. I know mine is. But it's a screamer up top. Gears is something else you'll have to think about.

 

alot of that has to do with the nature of the cam. bigger cams are designed for power in the upper rpms...sometimes at the cost of lower end power and smoothness.

when you get on it, let off then get back on it...could just be the computer lag trying to get the right a/f mixture. like it goes rich suddenly and is still in that mode but then is backed off...i wouldn't say it is abnormal.

my cam surges alot right now. but alot of it can be tuned out with manipulation of the a/f and spark at specific points in the tuning curve.

it's funny how the car will run fine at 55mph in 6th gear (1200rpm) but at 45 in 5th gear (1500) it starts bucking and shaking and surging. same thing happens if i do 35 in 4th gear (again 1500rpm or so). but if i shift to 5th and bring the revs down to 1200 it runs fine.

 

Different MAP vs. RPM load levels is all that is. 1500 RPM in 6th is a whole different MAP level than 1500RPM in 5th.

 

Good info. Thanks all.

 

Cam surge sucks. Makes you think all that money and hard work was to waste. To fix my surge I threw in taller gears. I had to set dwell and all that all over again (carb'ed motor).