EXPLAIN BIG CAM CHARACTERISTICS
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,765
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From: Dana Point Ca
EXPLAIN BIG CAM CHARACTERISTICS
I'm thinking of getting thunder racings new cam in my every day driver Z. I have seen over all the post that its a great daily driver if you dont mind "big cam characteristics" What does that mean? Will the car shake so bad at stop lights I'll get motion sickness? I talking with an excellent tune, so tuning wont be an issue.
Thanks :cheers: :yesnod:
Thanks :cheers: :yesnod:
Safety Car
Joined: Nov 2002
Posts: 4,394
Likes: 6
From: Melbourne FL
Re: EXPLAIN BIG CAM CHARACTERISTICS (vettethret)
That's a blanket statement 'big cam characteristics". You really need to know the specs of the cam to determine it's character.
What are the specs of the cam you are looking at? It will be a lot easier to determine the character knowing that.
What are the specs of the cam you are looking at? It will be a lot easier to determine the character knowing that.
Melting Slicks
Joined: Jun 2001
Posts: 2,743
Likes: 3
From: Davie Florida
Re: EXPLAIN BIG CAM CHARACTERISTICS (vettethret)
I believe the cam you are talking about is the new T.rex cam. That is a VERY big cam. I would hesitate to put that big of a cam in a daily driver. With a cam that big valve train reliability will be a big concern (replacing valve springs often). For peace of mind and better reliability I would go with a cam that is a bit less aggresive. Bigger is not always better.
[Modified by Mitch C, 11:43 AM 2/21/2004]
[Modified by Mitch C, 11:43 AM 2/21/2004]
Drifting
Joined: Oct 2002
Posts: 1,823
Likes: 1
From: If you can see the car behind you, your not going fast enough
Re: EXPLAIN BIG CAM CHARACTERISTICS (vettethret)
LOUD! is one, Lopey is another.... I just installed my cam shaft yesterday... it had a 110 LSA, it has a mean sound nad a rough idle, but not so rough that i cant have a drink in there.... The car shakes like it has the chills... ANd its a big step up in hp and the cops will tend to pull you over a little more under full throttle even if your under the speed limit... "My friend" got a ticket doing that... :p:
Safety Car
Joined: Nov 2002
Posts: 4,394
Likes: 6
From: Melbourne FL
Re: EXPLAIN BIG CAM CHARACTERISTICS (vettethret)
I think this is what you are referring to:
T-ReX v.2 - 242/248 - .608/.612 - 110 lsa 3500-6700 RPM
Personally, I don't think this is a good daily driver cam. My reason being that with this kind of duration you really push the power band up too high unless you have an auto with 3.93 or 4.10 gears and a higher stall TC. The 110 LSA will also give you a very lopey idle.
For a daily driver I would stay in the neighborhood of 112-114 LSA and around 230-240 duration. That's just my opinion. Take it for what it's worth.
Some people can manage a big cam like the T-Rex. But, that is more than I would like to deal with on a daily basis.
Good luck on your choice. Choosing a cam is one of the hardest to make. :cheers:
T-ReX v.2 - 242/248 - .608/.612 - 110 lsa 3500-6700 RPM
Personally, I don't think this is a good daily driver cam. My reason being that with this kind of duration you really push the power band up too high unless you have an auto with 3.93 or 4.10 gears and a higher stall TC. The 110 LSA will also give you a very lopey idle.
For a daily driver I would stay in the neighborhood of 112-114 LSA and around 230-240 duration. That's just my opinion. Take it for what it's worth.
Some people can manage a big cam like the T-Rex. But, that is more than I would like to deal with on a daily basis.
Good luck on your choice. Choosing a cam is one of the hardest to make. :cheers:
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Melting Slicks
Joined: Dec 2001
Posts: 2,040
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From: Collin County Texas
Re: EXPLAIN BIG CAM CHARACTERISTICS (vettethret)
..... Have you had it tuned yet ...
But with a big cam comes big power and if that is what you want, then there are tradeoffs you have to realize. Over on LS1.com and Ls1tech.com, I think they have posts on this cam.
Melting Slicks
Joined: Dec 2001
Posts: 2,040
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From: Collin County Texas
Re: EXPLAIN BIG CAM CHARACTERISTICS (tcmc5)
Regardless of tuning I believe you'll never pass whatever emissions testing you have out there.
Melting Slicks
Joined: Aug 2002
Posts: 2,737
Likes: 2
From: California USA
Re: EXPLAIN BIG CAM CHARACTERISTICS (Z06ufgrad2002)
:iagree: Also, maybe just my opinion, but cams ground on less than a 112 belong in carburated engines.
I don't have a problem w/the duration, though w/lower compression, power will be bled off through the exhaust port and maybe revert back via intake ports. The amount of excess fuel/air you scavenge will be good on top end, but closed loop computer operation will be a mess. Also, if your heads flow 550 lift and you add a cam good to 610 lift, you will kill power for sure.
I don't have a problem w/the duration, though w/lower compression, power will be bled off through the exhaust port and maybe revert back via intake ports. The amount of excess fuel/air you scavenge will be good on top end, but closed loop computer operation will be a mess. Also, if your heads flow 550 lift and you add a cam good to 610 lift, you will kill power for sure.
Team Owner
Joined: Apr 2001
Posts: 26,794
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From: Elmhurst, IL (West Suburb of Chicago) & Home of MEGA Horsepower
St. Jude Donor '06
Re: EXPLAIN BIG CAM CHARACTERISTICS (427CPE)
I would not RUSH to put that HUGE cam in as i would want it see it battle tested in the real world first as you otherwise will be a bit of a guinea pig.
I would suggest going with something radical yet proven and very streetable like the LGM G5X2 cam with specs of 232/240, .605 lift on a 112, 113 or 114 lsa or even the G5X3 cam which is a bit more radical than the above! :cheers:
I would suggest going with something radical yet proven and very streetable like the LGM G5X2 cam with specs of 232/240, .605 lift on a 112, 113 or 114 lsa or even the G5X3 cam which is a bit more radical than the above! :cheers:
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,765
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From: Dana Point Ca
Re: EXPLAIN BIG CAM CHARACTERISTICS (MTI 427 Roadster)
Thats probably a good call. The last thing I want to do right now is replace and engine in a brand new car with 5k on it. :cheers:
Drifting
Joined: Aug 2001
Posts: 1,260
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From: Thousand Oaks California
Re: EXPLAIN BIG CAM CHARACTERISTICS (vettethret)
BIG CAM CHARACTERISTICS usually implies
1.) Completely retailored torque curve where top end right up to rev cut is stronger by far but under 2000 rpm performance is weaker by far
2.) Idle is choppy sounding and feeling. May need to raise idle significantly which kills city fuel efficiency
3.) Clean emissions is tough to tune in
4.) Surging and idle hunt under certain conditions
5.) Valvetrain life issues (although high lift/small duration mild blower cams can be the hardest on valvetrain)
6a.) Requirement of higher stall (automatics) and/or higher gear ratio which in turn increases highway noise levels (exhaust and possibly gear whine), highway fuel consumption, etc.
6b.) For front-mounted transmissions (C4s and earlier), the requirement of a more expensive high speed driveshaft to prevent vibration and trans bushing wear comes hand in hand with higher ratio rear end gears...a chain reaction expenditure from putting a bigger cam.
7.) Even with higher ratio gear set, increased instances of stalling at a traffic light on take offs or parallel parking if you have a grabby clutch and you don't give enough gas
1.) Completely retailored torque curve where top end right up to rev cut is stronger by far but under 2000 rpm performance is weaker by far
2.) Idle is choppy sounding and feeling. May need to raise idle significantly which kills city fuel efficiency
3.) Clean emissions is tough to tune in
4.) Surging and idle hunt under certain conditions
5.) Valvetrain life issues (although high lift/small duration mild blower cams can be the hardest on valvetrain)
6a.) Requirement of higher stall (automatics) and/or higher gear ratio which in turn increases highway noise levels (exhaust and possibly gear whine), highway fuel consumption, etc.
6b.) For front-mounted transmissions (C4s and earlier), the requirement of a more expensive high speed driveshaft to prevent vibration and trans bushing wear comes hand in hand with higher ratio rear end gears...a chain reaction expenditure from putting a bigger cam.
7.) Even with higher ratio gear set, increased instances of stalling at a traffic light on take offs or parallel parking if you have a grabby clutch and you don't give enough gas
Safety Car
Joined: Nov 2002
Posts: 4,394
Likes: 6
From: Melbourne FL
Re: EXPLAIN BIG CAM CHARACTERISTICS (MTI 427 Roadster)
I would not RUSH to put that HUGE cam in as i would want it see it battle tested in the real world first as you otherwise will be a bit of a guinea pig.
I would suggest going with something radical yet proven and very streetable like the LGM G5X2 cam with specs of 232/240, .605 lift on a 112, 113 or 114 lsa or even the G5X3 cam which is a bit more radical than the above! :cheers:
I would suggest going with something radical yet proven and very streetable like the LGM G5X2 cam with specs of 232/240, .605 lift on a 112, 113 or 114 lsa or even the G5X3 cam which is a bit more radical than the above! :cheers:
Safety Car
Joined: Mar 2002
Posts: 4,928
Likes: 1
Cruise-In V Veteran
St. Jude Donor '09
Re: EXPLAIN BIG CAM CHARACTERISTICS (vettethret)
If you're not worried about emissions - go for it.
Run it open loop. With a decent tune you should be able to idle well at about 1000 RPM. A significant attribute of fuel injection is you don't need a strong signal (vacuum), at idle, for narrow LSAs - you can actually get a stable idle.
Run it open loop. With a decent tune you should be able to idle well at about 1000 RPM. A significant attribute of fuel injection is you don't need a strong signal (vacuum), at idle, for narrow LSAs - you can actually get a stable idle.
Safety Car
Joined: Mar 2002
Posts: 3,556
Likes: 2
Re: EXPLAIN BIG CAM CHARACTERISTICS (binksZ06)
With each step up in cam, there is an exponential expense in less drivability.
It also must be professionally tuned by someone who knows what they are doing.
Generally speaking, for each 10-15 RWHP jump above 425 you can expect to pay a bit in driveabiltiy, even with good LS1 editing.
My Cartek H cam (224/228 567/571 113 LSA) with Lingenfelter CNC LS6 11.2-1 heads seems to me the limit for a daily driver and long trip car w/o the big cam problems you can experience (with LS1 editing).
On a conservative dyno and conservative tuning in 85 degree humid weather I made over 423 to the rears, and it runs flawlessly with a 925 idle. Also still gets 28 mpg highway at 80 with the A/C on.
It also must be professionally tuned by someone who knows what they are doing.
Generally speaking, for each 10-15 RWHP jump above 425 you can expect to pay a bit in driveabiltiy, even with good LS1 editing.
My Cartek H cam (224/228 567/571 113 LSA) with Lingenfelter CNC LS6 11.2-1 heads seems to me the limit for a daily driver and long trip car w/o the big cam problems you can experience (with LS1 editing).
On a conservative dyno and conservative tuning in 85 degree humid weather I made over 423 to the rears, and it runs flawlessly with a 925 idle. Also still gets 28 mpg highway at 80 with the A/C on.