Mild L77 AFM compatible crow cam

[vr304]

So, one year on thought I might update my thread if anyones interested. Got talked out of the AFM cam and bit the bullet with AFM delete and crow 871777. (226/236 113 LSA .607/6.17). 329 rwkw she pulled. Standard stall.

What’s the drivability like? Any noticeable loss of down low torque?

 

[shane_3800]

So, one year on thought I might update my thread if anyones interested. Got talked out of the AFM cam and bit the bullet with AFM delete and crow 871777. (226/236 113 LSA .607/6.17). 329 rwkw she pulled. Standard stall.

I've been doing some research lately as, I soon am going to do a cam on my mates LS1 standard stall 4 speed.
That cam is on the limit for a 4 speed, I assume you have a 6 speed.

 

[Mr Bit]

What’s the drivability like? Any noticeable loss of down low torque?

Yeah she's at the borderline of needing a stall. Drivability still pretty good, very, very minor surging at rest if I ease off the brakes. Not enough to be worried about. Also just a tad jerky slowing to a stop. None of this fusses me, might fuss others though. Low down torque still ok-ish. Unfortunately with the auto she's definitely sluggish off the line until the cam comes in. A quality high stall is so bloody expensive so I'll just persist with it. I did however recently swap the 2.92 final drive with a 3.27, this helped a bit with getting off the line.

 

[Mr Bit]

I've been doing some research lately as, I soon am going to do a cam on my mates LS1 standard stall 4 speed.
That cam is on the limit for a 4 speed, I assume you have a 6 speed.

Yeah mate 6l80e in my VF 1.

 

[Mr Bit]

And a bit more info if you're keen to see what she does now with the cam, got a best of 4.81 seconds 0-100 with the old 2.92 diff using a phone GPS timer (did 3-4 attempts, all about the 5 s mark). Havn't tried with the 3.27 yet so will go a bit lower. Also have to experiment with traction control off/on etc..........so see what gets me there quicker.

Fuel consumption.........................terrible! 19-20 l/100 around town with stop/starts. Highway........pretty good. 9-10 l/100 cruising at 110. Was to be expected however with about 25% more lift over the AFM cam.

 

[shane_3800]

And a bit more info if you're keen to see what she does now with the cam, got a best of 4.81 seconds 0-100 with the old 2.92 diff using a phone GPS timer (did 3-4 attempts, all about the 5 s mark). Havn't tried with the 3.27 yet so will go a bit lower. Also have to experiment with traction control off/on etc..........so see what gets me there quicker.

Fuel consumption.........................terrible! 19-20 l/100 around town with stop/starts. Highway........pretty good. 9-10 l/100 cruising at 110. Was to be expected however with about 25% more lift over the AFM cam.

It's not the lift it's the duration.

The peak lift number is just a guide, what you want in lift is good mid lift figures.
All this can be seen when you have a cam graph.

I think the main reason the lift gets increased is to keep the ramp rate the same, if you added in too much duration without lift the valve would be told to stop but its mass would continue moving it making it crash the lifter.

 

[RevNev]

I think the main reason the lift gets increased is to keep the ramp rate the same, if you added in too much duration without lift the valve would be told to stop but its mass would continue moving it making it crash the lifter.

Lift is increased to open the port more and increase flow. You can run a long duration cam at low or near stock lift no problems at all. High lift is hard on lifters and valve train and best not to exceed 0.600" lift for durability on an LS street engine.

 

[keith reed]

Who's PirAte?

This the first time I have read through this thread. PirAte is a departed member. Tended to disagree with other members.

 

[shane_3800]

Lift is increased to open the port more and increase flow. You can run a long duration cam at low or near stock lift no problems at all. High lift is hard on lifters and valve train and best not to exceed 0.600" lift for durability on an LS street engine.

Yes thanks, I'm well versed in cam dynamics and how lift helps flow.
I'm not going to get into a discussion on lift vs duration.
But generally duration increases the VE.
You have to remember that peak lift is only a peak figure, you don't hold the valve there for very long, so it's effect on VE is relatively small compared to the mid lift zone.

My point was peak lift is more a result of getting the ramp rates correct for the mid lift areas of the cam where most of the flow happens.

If you don't believe me about ramp rates and pressure angles you can look up Ben Strader as he has numerous articles on this subject.

 

[RevNev]

If you don't believe me about ramp rates and pressure angles you can look up Ben Strader as he has numerous articles on this subject.

I'm not interested in re-posts on something you've read, and I'll tell you why.

My experience with race engines and camshafts began in 1980 when building a 1345cc Mini engine running on methanol with a 45 DCOE Weber carby for junior speedway. The car won the state title in '81 and '82 until the driver moved to seniors.

Moving on to today, my race engines have won 4 Australian titles in production-based circuit racing, 16 state titles across 3 different categories and hold current lap records at Mallala, The Bend, Wanneroo WA, Sandown VIC, Winton VIC, Eastern Creek NSW, Bathurst NSW and Simmons Plains TAS.

As I've mentioned previously, I post about things I've experienced or opinions on that basis and like others who share their valuable experiences and opinions greater than something they've read about, perhaps you can do the same instead?