Camshafts / Boost

[gimmie11s]

I'm not an engine builder ......

Obvious quote of the day.

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[gimmie11s]

If the OP is blower limited, he has no choice but to increase engine horsepower. Whether that's cams, exhaust, intake manifold etc. It will make more power boosted, with more naturally aspirated power.

Where did he say he's blower limited?

 

[Leonidas514]

These forums crack me up! I'm sure you are an engine builder too? I'm actually a little confused as to what was so confusing about the word breathe? Wouldn't a larger lobed camshaft allow more air to flow? In other words, breathe?

 

[80FoxCoupe]

Where did he say he's blower limited?

That was just an assumption on my end. He has a p1x and is talking about building an engine. At that point he would be blower limited for sure, if not now. If one is blower limited and building an engine, cams would certainly be a viable option.

 

[Hack]

These forums crack me up! I'm sure you are an engine builder too? I'm actually a little confused as to what was so confusing about the word breathe? Wouldn't a larger lobed camshaft allow more air to flow? In other words, breathe?

If the heads are well designed they might not flow more with more lift. Making the ports oversized can hurt engine performance as much as making them undersized. So, AFAIK the factory will have the ports optimized to work with the cams. Bigger cams (more lift) might not do much.

Now of course more duration will provide more flow, but may hurt emissions and driveability (who of us really care about those things, right?). This typically hurts the bottom end and makes the idle rougher, but gives more power up top.

If you add too much duration you will have to lock out the cam phasers to prevent the valves and pistons from touching, which will get rid of the TiVCT that gives the engine great low + also great top end. Without TiVCT you will lose more low end on top of what the longer duration cams are losing for you.

BTW, I'm not an engine builder either. IMO your best bet is talk to a trustworthy place like Comp Cams and see what they recommend for your usage.

Edit: you should expect to have to change valve springs with a cam change.

 

[Leonidas514]

Thanks for the reply man!

I have landed on stock Gen 2 cams and stock gen 2 heads with oversize valves and heavier springs. Again, thanks for taking the time to provide an answer/advice.

 

[80FoxCoupe]

If the heads are well designed they might not flow more with more lift. Making the ports oversized can hurt engine performance as much as making them undersized. So, AFAIK the factory will have the ports optimized to work with the cams. Bigger cams (more lift) might not do much.

Now of course more duration will provide more flow, but may hurt emissions and driveability (who of us really care about those things, right?). This typically hurts the bottom end and makes the idle rougher, but gives more power up top.

If you add too much duration you will have to lock out the cam phasers to prevent the valves and pistons from touching, which will get rid of the TiVCT that gives the engine great low + also great top end. Without TiVCT you will lose more low end on top of what the longer duration cams are losing for you.

BTW, I'm not an engine builder either. IMO your best bet is talk to a trustworthy place like Comp Cams and see what they recommend for your usage.

Edit: you should expect to have to change valve springs with a cam change.

Mr Conservative!

 

[gimmie11s]

That was just an assumption on my end. He has a p1x and is talking about building an engine. At that point he would be blower limited for sure, if not now. If one is blower limited and building an engine, cams would certainly be a viable option.

Fair enough but I'd upgrade the blower way before i installed bigger cams.

If the heads are well designed they might not flow more with more lift. Making the ports oversized can hurt engine performance as much as making them undersized. So, AFAIK the factory will have the ports optimized to work with the cams. Bigger cams (more lift) might not do much.

Now of course more duration will provide more flow, but may hurt emissions and driveability (who of us really care about those things, right?). This typically hurts the bottom end and makes the idle rougher, but gives more power up top.

If you add too much duration you will have to lock out the cam phasers to prevent the valves and pistons from touching, which will get rid of the TiVCT that gives the engine great low + also great top end. Without TiVCT you will lose more low end on top of what the longer duration cams are losing for you.

BTW, I'm not an engine builder either. IMO your best bet is talk to a trustworthy place like Comp Cams and see what they recommend for your usage.

Edit: you should expect to have to change valve springs with a cam change.

Bingo!! This man gets it.

For the #racecar guys... sure.. go for it.

For street car guys... nope. I, for one, have had enough cam'd vehicles to know i dont want to deal with the drivability issues, poor combustion at low RPM, engine stalling, broken valve springs, non-working VCT, and other stuff that goes along with cams.

Again... racecar, sure. Fast street car? Nope.

Too many people have made weeeeell over 1k horsepower on this platform with STOCK cams, with great drivability, with cranking A/C in 100* heat. That is more my speed... but your mileage may vary!!

 

[gimmie11s]

These forums crack me up! I'm sure you are an engine builder too? I'm actually a little confused as to what was so confusing about the word breathe? Wouldn't a larger lobed camshaft allow more air to flow? In other words, breathe?

Yep, Mr Dipshit is in the middle of an engine build right now in his garage....... and will not be "upgrading" cams.

But WTF do i know? Do yourself a favor and ignore everything i say.

 

[80FoxCoupe]

Fair enough but I'd upgrade the blower way before i installed bigger cams.




Bingo!! This man gets it.

For the #racecar guys... sure.. go for it.

For street car guys... nope. I, for one, have had enough cam'd vehicles to know i dont want to deal with the drivability issues, poor combustion at low RPM, engine stalling, broken valve springs, non-working VCT, and other stuff that goes along with cams.

Again... racecar, sure. Fast street car? Nope.

Too many people have made weeeeell over 1k horsepower on this platform with STOCK cams, with great drivability, with cranking A/C in 100* heat. That is more my speed... but your mileage may vary!!

Id likely upgrade the blower over cams also if i could only do one or the other. Easy for TT coyote combos to run stock cams, just add more boost since very few TT cars are maxed out. Not necessarily the case with a maxed out blower combo. There can def be reliability issues that need to be taken into consideration. But to say 1000hp or more can be made with the stock cams does not mean they are the best choice for every boosted combo. But if one could meet thier goals with stock cams, thats def the way to go.

It looked like initially he thought new oem cams were close to the cost of aftermarket cams. So i can understand the ask.

For me, as long as im running some type of supercharger ill be running aftermarket cams. Cause my shit is maxed out LOL

 

[gimmie11s]

Id likely upgrade the blower over cams also if i could only do one or the other. Easy for TT coyote combos to run stock cams, just add more boost since very few TT cars are maxed out. Not necessarily the case with a maxed out blower combo. There can def be reliability issues that need to be taken into consideration. But to say 1000hp or more can be made with the stock cams does not mean they are the best choice for every boosted combo. But if one could meet thier goals with stock cams, thats def the way to go.

It looked like initially he thought new oem cams were close to the cost of aftermarket cams. So i can understand the ask.

For me, as long as im running some type of supercharger ill be running aftermarket cams. Cause my shit is maxed out LOL

good post, totally agree

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