new to cam- questions on its drivability (normal?)
01-08-2006, 11:52 PM
#1
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new to cam- questions on its drivability (normal?)
okay, basically ive been through hell and back getting the valvetrain and cam installed in my car. Well i ended up biting the bullet and bringing to a shop and just got car back 2 days ago.
97 LT1 - 110k on motor
Comp Pro Mags 1.6
Comp 918 Beehives
Hardened pushrods
CC XE 230/236 112lsa
Tune By Ion (madz)
thats basically the cam and valvetrain i installed. Car starts up on first try and will sometimes need a little gas once its idling to keep it from stalling for the first few seconds.. After that she idles at roughly 900 rpm (ion set to 850 so could just be off). While idling i notice it drop a bit and go back up every few seconds but she will continue idling on her own.
When backing up i have to rev it slightly and feather clutch to keep the RPM's from dropping too low but she will idle fine when clutch is fully engaged or out of gear.
Anywhere under 2k if im lightly accelerating my car will buck be real difficult to drive however if i bring it over 2k or give it a bit of gas it stops. I assume this is just cam surge but im curious if it should be that strong with my cam and ions tune.
other than that she pulls like hell all the way to over 6k and once shes warmed up idles much smoother.
Guess what im asking is is this what i should be expecting.. i have no problems living with it im just not sure what i should be expecting. I dont want it to turn out it shouldnt be this bad and hte shop missed something.
97 LT1 - 110k on motor
Comp Pro Mags 1.6
Comp 918 Beehives
Hardened pushrods
CC XE 230/236 112lsa
Tune By Ion (madz)
thats basically the cam and valvetrain i installed. Car starts up on first try and will sometimes need a little gas once its idling to keep it from stalling for the first few seconds.. After that she idles at roughly 900 rpm (ion set to 850 so could just be off). While idling i notice it drop a bit and go back up every few seconds but she will continue idling on her own.
When backing up i have to rev it slightly and feather clutch to keep the RPM's from dropping too low but she will idle fine when clutch is fully engaged or out of gear.
Anywhere under 2k if im lightly accelerating my car will buck be real difficult to drive however if i bring it over 2k or give it a bit of gas it stops. I assume this is just cam surge but im curious if it should be that strong with my cam and ions tune.
other than that she pulls like hell all the way to over 6k and once shes warmed up idles much smoother.
Guess what im asking is is this what i should be expecting.. i have no problems living with it im just not sure what i should be expecting. I dont want it to turn out it shouldnt be this bad and hte shop missed something.
01-09-2006, 12:22 PM
#4
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Join Date: Jan 2004
Location: Downey, CA
Posts: 1,406
Re: new to cam- questions on its drivability (normal?)
Sounds normal to me too. Also, the tach on the LT1 reads about 100 RPM
high most of the time. My idle is set to 850, but reads as 1000 on the tach.
Although many will claim daily driver smoothness with a CC306 or similar
cams, it's just not the case. What you are seeing is the reality of a big cam
with gobs of power up high and not much below 2,000.
high most of the time. My idle is set to 850, but reads as 1000 on the tach.
Although many will claim daily driver smoothness with a CC306 or similar
cams, it's just not the case. What you are seeing is the reality of a big cam
with gobs of power up high and not much below 2,000.
01-09-2006, 07:16 PM
#5
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Location: Chicago, IL
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Re: new to cam- questions on its drivability (normal?)
I don't see any gears in your sig, when i talked to atljar he told me that swaping gears to 4.10's or higher helped out alot with the cam surging and kept the low speed and low rpm driving easier
Last edited by My Iroc Z28; 01-09-2006 at 07:20 PM.
01-09-2006, 07:22 PM
#6
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Location: Kansas
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Re: new to cam- questions on its drivability (normal?)
Some fine tuning will make a difference and it sounds like you need to crack the TB blades a little to help the off idle issue. The cam just overwhelms the IAC motor and it cant compensate fast enough to keep the RPMs up. But other than that... what you are experiencing are just the downsides of running a large cam in a 350.
01-09-2006, 07:29 PM
#7
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Re: new to cam- questions on its drivability (normal?)
Originally Posted by My Iroc Z28
I don't see any gears in your sig, when i talked to atljar he told me that swaping gears to 4.10's or higher helped out alot with the cam surging and kept the low speed and low rpm driving easier
ya- was planning on picking up a 12bolt with 4.10s this coming month but just got slapped with huge bill so gonna have to hold off.. im getting some dyno time this spring with a really good tuner so im gonna see if he can help it a bit.. also remember reading somewhere something about a drill mod to the TB
gonna look into that a bit
01-09-2006, 07:38 PM
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Location: Chicago, IL
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Re: new to cam- questions on its drivability (normal?)
Originally Posted by kingman109
ya- was planning on picking up a 12bolt with 4.10s this coming month but just got slapped with huge bill so gonna have to hold off.. im getting some dyno time this spring with a really good tuner so im gonna see if he can help it a bit.. also remember reading somewhere something about a drill mod to the TB gonna look into that a bit
gonna look into that a bit
01-09-2006, 09:05 PM
#9
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Re: new to cam- questions on its drivability (normal?)
basically from what i can tell- if the cracking of the throttle blades open doesnt do it for me -
You dont actually make a new hole but simply enlarge the existing one in the TB. Take a look at the center of the TB from the front side. Just below center is a hole which bypasses the IAC motor but still feeds air to the IAC passages... making it larger allows more air through which should prevent the stalling problem. This does only apply if its a stock TB though.
Just got done fighting a similar issue with my car. After you have determined there are no vacume leaks, and closed your throttle blades and readjusted the TPS, pull the TB off and drill out the hole that is in the lower part down by the IAC, between the throttle blades a little bit bigger. This cured my problem.
I ended up drilling mine out 1/32" bigger than the original size. It seems a lot of cammed cars have this issue, I spent hours searching this site for info on it.
I ended up drilling mine out 1/32" bigger than the original size. It seems a lot of cammed cars have this issue, I spent hours searching this site for info on it.
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