What Vacuum with cams.

[MattZ281LE]

What kind of vacuum are guys running with cams and what mods. Whats your idle speed.

I am trying to get an idea on my cam.


My unknown cam idles at 8-9" at 900

- Matt

 

[MattZ281LE]

Anyone

 

[4Jenna]

12" at 750rpm
331/T-trim
Cam Motion Custom Cam .542/.565 228.232 114lsa

 

[Grn92LX]

Appx 10" at a 900 ish rpm idle. Fairly healthy n/a FTI hydro roller

 

[Joes95GT]

Trying to determine cam specs from vacuum readings is absolutely senseless. Duration, Lobe Separation and IC play factors in vacuum. Wide LSAs pull higher vacuum readings, and bigger durations can bring them down....it's the combination of everything....

Joe

 

[MattZ281LE]

Not really looking for any specs. Curious about other combos characteristics and idle quality. My cam is very peaky. I am thinking of dumping it in favor of a custom.

If I wanted to know specific specs. I could use a dial indicator and degree wheel to get the duration and lift values.

 

[tmoss]

Your dyno graph does not look "peaky" but that is a personnal thing when judging against it's driveability - it would be fun to see a custom and a re-dyno.

 

[zenboy99]

I'm pulling 13 at idle. High lift, short duration cam 111LSA

 

[MattZ281LE]

Mainly I want to lower the RPM band. Torque is peaking at 5500 and HP has no sign of letting up. Yes it seems very linear on the graph.
It has OK driveability. Does not like being below 1500-1600 rpm. Low speed parking lots are a pain. It really comes alive at 3500 and gets stupid. But I think that is the blower.
I have to be QUICK shifting it at full throttle in 1st and 2nd. Rpms go from 2500-7000 is a split second.

 

[tmoss]

It's a beast - they might not drive well in parking lots Matt! Is this a race engine in a street car? I'll be the first to admit I'm not familair with your boost curve but it probably isn't much at low rpms and the induction system is set up for rpm - it's gonna be soft down low.

I think if you work with a good cam guy you will be able to tame the beast some if you have (can get your hands on) the specs of the cam that is in there when you work with your custom cam supplier.

best of luck to you Matt...........

 

[gmkillr]

Im pulling around 20" w/ the stock cam at an idle of 1200rpm

 

[Zero Signal]

10-12" , .533 total lift, 218° duration @ .050, 110° LSA

 

[4Jenna]

Im pulling around 20" w/ the stock cam at an idle of 1200rpm

idle@1200rpm and a stock cam...????

 

[gmkillr]

idle@1200rpm and a stock cam...????

I set it that high cause my old battery could barely keep a charge at 700-800, but I now have an Optima yellowtop and just never turned it back down yet.