[shinysun]

Hello,

My car got installed TSP stage 1 CAM, and feel a lot of shake at idle sometimes.
I was told the cam doesn't have that rough idle, but not sure if it is.

If you see the video and see the coolant bottle, you can see the shake easily.
Can I reduce the shake by tune? or just it is natural with CAM?

https://youtu.be/g7_yMJXwVYg

Thanks,

[Hyper SS]

What is the LSA?

[danhr]

Could be loose motor mounts.

[shinysun]

Originally Posted by Hyper SS

What is the LSA?

116

[shinysun]

Originally Posted by danhr

Could be loose motor mounts.

Actually, the entire car is dancing at idle sometimes and if the car is rolling , the shake is all gone.

[Hyper SS]

Originally Posted by shinysun

116

That's not a lopey cam

[danhr]

Originally Posted by shinysun

Actually, the entire car is dancing at idle sometimes and if the car is rolling , the shake is all gone.

Pretty sure it’s your tune then. Too much fuel will make it “chop”

[WhiteNight]

The LSA doesn't dictate the shake. If there is some chop at idle the motor will wiggle. I've had all sorts of cams and they all had some shake/vibration at idle.

[KingLT1]

Originally Posted by Hyper SS

What is the LSA?

LSA does not have anything to do with cam lope...Overlap does.

That being said, from what I see in the vid looks normal. The engine shakes as it comes in and out of loping...typical for a cam car. You could probably smooth it out some more with tuning.

[danhr]

Originally Posted by KingLT1

LSA does not have anything to do with cam lope...Overlap does.

That being said, from what I see in the vid looks normal. The engine shakes as it comes in and out of loping...typical for a cam car. You could probably smooth it out some more with tuning.

Correct and incorrect. Overlap and LSA are connected. Overlap can be found by either using the seat time of the intake and exhaust valves (add intake and exhaust opening times)

OOORRRR

by using duration and subtracting LSA (add durations, divide by 4, subtract LSA, then multiply by 2)

So the tighter your LSA, the less you would subtract from your durations, which means you would have a higher number (which means more overlap)



also, here are the cam specs for the OP's cam, from TSP's website

Cam Specs:*227/231, .635"/.635", 116 LSA

it's a pretty small cam, with a pretty wide LSA, which would make sense for a blower car. Again, I would look at the fueling at idle. Running a car rich at idle is an easy way to get it to start, but leads to crappy idling characteristics. I remember when I was messing out with a 231/236 cam in my 5th gen, and I threw so much fuel at it, at idle, it would sound like a TREX camm'ed car. bbuuutttt it would foul the plugs in 2 blocks. lol.

[shinysun]

Originally Posted by danhr

Correct and incorrect. Overlap and LSA are connected. Overlap can be found by either using the seat time of the intake and exhaust valves (add intake and exhaust opening times)

OOORRRR

by using duration and subtracting LSA (add durations, divide by 4, subtract LSA, then multiply by 2)

So the tighter your LSA, the less you would subtract from your durations, which means you would have a higher number (which means more overlap)



also, here are the cam specs for the OP's cam, from TSP's website

Cam Specs:*227/231, .635"/.635", 116 LSA

it's a pretty small cam, with a pretty wide LSA, which would make sense for a blower car. Again, I would look at the fueling at idle. Running a car rich at idle is an easy way to get it to start, but leads to crappy idling characteristics. I remember when I was messing out with a 231/236 cam in my 5th gen, and I threw so much fuel at it, at idle, it would sound like a TREX camm'ed car. bbuuutttt it would foul the plugs in 2 blocks. lol.

Thank you for the comments.
How can I adjust the fueling in close loop for gen5 lt1 engine? I believe that the fuel trim always tries to make AFR to the stoich while the overlap of cam leads o2 sensor to lean condition, and it will make the cylinder the richer.

[JANNETTYRACING]

This is not a fuel or timing issue I have seen the logs.

Pretty normal for that cam.

Ted.

[PRAY]

Originally Posted by shinysun

Thank you for the comments.
How can I adjust the fueling in close loop for gen5 lt1 engine? I believe that the fuel trim always tries to make AFR to the stoich while the overlap of cam leads o2 sensor to lean condition, and it will make the cylinder the richer.

Exactly, the 02 sensors are in control at idle and normal drive conditions and are shooting for stoich in CL. You can make a cam chop more or less with timing. But with the GEN 5 motor, idle timing is controlled by TQ tables. So it's not like the old days when you could just add or pull timing for a desired sound.

If Ted says the logs are good then they are good. That cam isn't all that small but I think the overlap at .050" is very minimal.

[KingLT1]

Originally Posted by danhr

Correct and incorrect. Overlap and LSA are connected. Overlap can be found by either using the seat time of the intake and exhaust valves (add intake and exhaust opening times)

OOORRRR

by using duration and subtracting LSA (add durations, divide by 4, subtract LSA, then multiply by 2)

So the tighter your LSA, the less you would subtract from your durations, which means you would have a higher number (which means more overlap)



also, here are the cam specs for the OP's cam, from TSP's website

Cam Specs:*227/231, .635"/.635", 116 LSA

it's a pretty small cam, with a pretty wide LSA, which would make sense for a blower car. Again, I would look at the fueling at idle. Running a car rich at idle is an easy way to get it to start, but leads to crappy idling characteristics. I remember when I was messing out with a 231/236 cam in my 5th gen, and I threw so much fuel at it, at idle, it would sound like a TREX camm'ed car. bbuuutttt it would foul the plugs in 2 blocks. lol.

i have seen 116 lsa cams chop harder then a 112 lsa cam. so again LSA does not really mean the cam is going to chop harder. Now take the same duration specs such as 219/231 with a 116 lsa then use the same duration with a lsa of 112, the 112 cam will chop harder because overlap increased...but again the main ingredient for cam chop is overlap not LSA.

also since it's a vvt cam, depending how far advanced it is at idle could contributing to the cam chop. I believe that is why most VVT NA cams use a higher LSA.