[Z OH 6]

Originally Posted by 6spdhyperblue

Is that true? A very large cam better with a manual trans?

The drivability is easier with a manual since the trans won't require a loose converter and possibly TCM tuning to help with the drivability.

[KingLT1]

Originally Posted by 6spdhyperblue

Is that true? A very large cam better with a manual trans?

Large cam is best suited for- Stalled Auto > Manual > Stock stall Auto. Honestly I wouldn't consider running a large cam on a stock stall NA car. A PD blower car will still have a fat torque curve either way and still run good. You just have to deal with some potential drive-ability issues such as pulling through the brakes from increased idle speed and bucking/surging from the stock trans tune forcing the converter to lock up in all gears at part throttle. Ideally when you Cam a automatic you run a loose converter that doesn't lock part throttle and that soaks up some of the cams erratic behavior at low speed tip in throttle range.

Either way there is no point to run a large cam on a blower car. You don't need the overlap to make power because you have a external air pump forcing the engine to breath. So why take the driveability hit for little performance gain? Aside from that most here talking about cams in ZL1's are not really large cams.


This is what I would run in a stock stall car...or at least something along this line maybe with less lift. The cam in vid is a LPE GT35 with 38% fuel lobe.

[Snowwolfe]

Originally Posted by CW3SF

My last car was 750hp. My ZL1 feels slow. Can always use a few more hp on the backstretch at the track.

Not surprised at the elevation you live at.

[Idaho2018GTPremium]

OK another question: I've heard a few times now that the TCM is "torque based". If that is the case, how are FBO or more ZL1s running more power to the rear tires if the TCM won't allow more than a given amount of torque?

[Z OH 6]

Originally Posted by Idaho2018GTPremium

OK another question: I've heard a few times now that the TCM is "torque based". If that is the case, how are FBO or more ZL1s running more power to the rear tires if the TCM won't allow more than a given amount of torque?

I'm not a tuner, but from what I gather the ECM has torque tables that can be manipulated.

[KingLT1]

Originally Posted by Idaho2018GTPremium

OK another question: I've heard a few times now that the TCM is "torque based". If that is the case, how are FBO or more ZL1s running more power to the rear tires if the TCM won't allow more than a given amount of torque?

Yes the ECU is torque based but it can be adjusted to allow more torque and not close the throttle.

[danhr]

Originally Posted by Idaho2018GTPremium

OK another question: I've heard a few times now that the TCM is "torque based". If that is the case, how are FBO or more ZL1s running more power to the rear tires if the TCM won't allow more than a given amount of torque?

your torque tables aren't exact representations of how much torque you are making. On previous years, you could increase the torque values. essentially when you press the pedal down, you are requesting xxx amount of torque. the ecm and tcm then go to work to give you that amount of torque. at least that's my understanding of it...… someone might chime in that knows more than me.

Originally Posted by Z OH 6

I'm not a tuner, but from what I gather the ECM has torque tables that can be manipulated.

the ecm torque tables have to match the tcm torque tables. if not, the car won't do anything. The TCM torque tables can't be changed.

"BuT YoU CaN Do AnYTHinG to A 2020+!!!!"

[Z OH 6]

Originally Posted by danhr

"BuT YoU CaN Do AnYTHinG to A 2020+!!!!"

Correct, except adjust the TCM for now. Otherwise, spot-on.

[danhr]

Originally Posted by Z OH 6

Correct, except adjust the TCM for now. Otherwise, spot-on.

[Idaho2018GTPremium]

Originally Posted by danhr

your torque tables aren't exact representations of how much torque you are making. On previous years, you could increase the torque values. essentially when you press the pedal down, you are requesting xxx amount of torque. the ecm and tcm then go to work to give you that amount of torque. at least that's my understanding of it...… someone might chime in that knows more than me.



the ecm torque tables have to match the tcm torque tables. if not, the car won't do anything. The TCM torque tables can't be changed.

"BuT YoU CaN Do AnYTHinG to A 2020+!!!!"

Originally Posted by Z OH 6

Correct, except adjust the TCM for now. Otherwise, spot-on.

You both have strong opinions on this. One is basically saying you can't do anything because the TCM is locked out, while the other is saying you can do FBOs + heads + mild cam and adjust the torque tables in the ECM to compensate.

I don't know which to believe since both of you seem very confident - although I am inclined to believe the guy with a ZL1 over the guy with a supercharged SS.

Anyone else care to chime in that has a FBO+ ZL1 and what was done to their car to make sure the extra power can be used and not neutered by the TCM lockout?

[Z OH 6]

Originally Posted by Idaho2018GTPremium

You both have strong opinions on this. One is basically saying you can't do anything because the TCM is locked out, while the other is saying you can do FBOs + heads + mild cam and adjust the torque tables in the ECM to compensate.

I don't know which to believe since both of you seem very confident - although I am inclined to believe the guy with a ZL1 over the guy with a supercharged SS.

Anyone else care to chime in that has a FBO+ ZL1 and what was done to their car to make sure the extra power can be used and not neutered by the TCM lockout?

You don't have to listen to us, call some top shops and ask around.

Call or E-mail Vengeance Racing, one of the top shops in the country for late model GM. They will explain your options.

When I asked about packages for my car, the first package they recommended was a stage IV package which includes a cam. I chose not to install a cam at this time and went with a stage III package but left the option on the table for next year. I literally asked them about 30 or more questions and they were always responsive and always gave honest answers. The most professional performance shop I've ever dealt with.

[JSH]

Not sure how you define large and I'm also not sure about HPE cam specs but my 200 additional top-end HP come largely from a different cam design and 2# boost.

I believe as we increase boost we should leave stock behind and increase LSA, which keeps boost pressure from going out the exhaust during valve overlap. And we're going to want more duration and lift on the exhaust side when the exhaust valve finally opens.

My point is, I would think there's significant power to be had by changing only LT4 cam design.

I'm also 100% certain that past or present GM LT4 engineers have long ago answered all such questions.

Originally Posted by KingLT1

Either way there is no point to run a large cam on a blower car.

[arpad_m]

Originally Posted by KingLT1

Yes the ECU is torque based but it can be adjusted to allow more torque and not close the throttle.

As a bit of steam relief, heartfelt congratulations to King on his 4000th post, many-many of which have been extremely helpful and educational. Thank you very much, Sir

[JSH]

Yes, King is extremely knowledgeable and particularly helpful to a guy like me who is new to the Gen 6 Camaro and LT4. He consistently shortens my rabbit trails.

Originally Posted by arpad_m

As a bit of steam relief, heartfelt congratulations to King on his 4000th post, many-many of which have been extremely helpful and educational. Thank you very much, Sir