Okay, after cooking my brain I'm calling on the tech junkies to show me the light here. We're grasping at straws in a 3v swap into a '01 GT that took a serious turn for disappointment, and it's been one lead-lined wall after the next trying to sort through possible explainations. So here's the break down for you guys, if any additional info is needed, just let us know.
This motor is a stock 3v longblock, about 80k/mi. It's got most of the Logan Motorsports 3v swap components. IAC relocate, 05+ Fuel Rails/FPS adapter, 05+ MAF w/VMP MAF adapter, long tubes, O/R X, Flowmasters, 05+ JLT II (converted), Cobra TB, stock 3v WAP shortblock, stock heads, stock intake manifold w/Steeda Delete Plates, Steeda UDP. All this is in a 2001 GT, built 3650, Exedy Mach 400, FRPP 4.10's.
The cams are Comp Cams 127020 with BBR Phaser Lockouts.
We got the car dyno tuned wednesday, and this combo laid down 285whp/282wtq. I was expecting by using the phaser lockouts some top end loss and possible torque peak gain. As I understand, locking the phasers puts the cams at 0, with respects to factory cam degree. I've used my car as a base platform ('08 GT, as listed below) for the build combo. Stone stock, my car laid down 283whp/302wtq @10.5 AFR factory tune. With these cams, JLT II, and O/R X the car put down 330whp/325wtq. With the addition of the FRPP manifold and Long Tubes the car made 363/321wtq.
On the final build I also had the VCT "tune locked" as in the cam timing tables were all "0" and the car made 347whp. With the max cam timing being 17, it puts down 363. So a 16whp difference from phasers being allowed up to 17 degrees retard.
The '01 GT should have put down 300-320 by my assumption, and around the same torque. Obviously, it fell far short of that, and we can't figure out why. It barely makes a bolt-on 2v's power, and less torque. Tuner went through everything he could think of, maxed the spark advance 'til it didn't make any more power, AFR was tits on 12.8. There was nothing more he could tune for, and everything was working properly. We even tested the dyno to make sure it was accurate, it too was bang on.
The car's powerband pulls to 6200 at crest, as it should with these cams/manifold in combo. Even the hp/tq balance is as expected. Just the entire powerband is down on power by at least 30-50hp/tq by all rights.
We took the car on a street romping for further testing. The engine sounds like it's struggling, even "feels" like it's struggling to make power. It's like the engine is screaming, but the power's just not coming out. Hard to explain. All I can say, is it doesn't sound right, compared to the sound of my 3v. I understand the purpose of VCT and it's advantages in efficiency and extending top end power. But we overlayed my dyno runs against the '01 GT's, and it's simply down on power accross the entire curve. In other words, from 2k-5k where I have 0 cam timing, and he's locked out as well, I dwarf his curve in power, even though the curves are identical in slope.
All that said, so far we've covered a compression and leak-down test, both check out good. 145psi is the lowest, 153psi is the highest. Most are right on 150psi. All the valves held 100psi for the leakdown as well. We've inspected the cams/phasers to make sure the right cam is on the right head and what not, just to eliminate all possibilities. Tomorrow we'll be pulling the timing cover and checking chain timing, pulling the followers to make sure they're all true, and even phaser/cam alignment. To be honest I'm completely stumped. This is my build, it's proven already. If he made 300whp/300wtq I might not be so critical about it, at least it's close! Hell, weather could account for even 10whp/wtq, maybe a hair more even. But he's coming in 30-50hp/tq shy, which is considerably under a stock 3v. I'll also be contacting Keith Logan, who has had several successful 3v swaps that yield 300-310whp/320-330wtq with just CAI/LT/OR Pipes/Tune on stock cams locked out. Maybe he knows of something tune-wise, like a mystical check box a tuner is supposed to check or uncheck for 3v swaps(??)
One of our theories was that maybe the 127020's aren't meant to be locked out, and this is the cause of his major lack of power production, since the longblock checks out tight. The problem is, we're running out of cracks to look in for this missing power. It's a lot of power for this combo to not be making. We're contemplating swapping him to stock cams, as most of the other 3v swaps are based, and seeing what happens with his power. But I'd like to have a sound word of confirmation that this would be the correct route to look down, as it doesn't make sense for a stock cam to make bigger gains N/A over an aftermarket cam. The 127020's are by no means a radical cam, but over stock, it's been a major improvement in my build ups, why would locking them prove not only ineffective, but produce power LOSS.
Once we've eliminated the timing chains from being off timing, and cam/follows being true, where the hell do we look next???
This motor is a stock 3v longblock, about 80k/mi. It's got most of the Logan Motorsports 3v swap components. IAC relocate, 05+ Fuel Rails/FPS adapter, 05+ MAF w/VMP MAF adapter, long tubes, O/R X, Flowmasters, 05+ JLT II (converted), Cobra TB, stock 3v WAP shortblock, stock heads, stock intake manifold w/Steeda Delete Plates, Steeda UDP. All this is in a 2001 GT, built 3650, Exedy Mach 400, FRPP 4.10's.
The cams are Comp Cams 127020 with BBR Phaser Lockouts.
We got the car dyno tuned wednesday, and this combo laid down 285whp/282wtq. I was expecting by using the phaser lockouts some top end loss and possible torque peak gain. As I understand, locking the phasers puts the cams at 0, with respects to factory cam degree. I've used my car as a base platform ('08 GT, as listed below) for the build combo. Stone stock, my car laid down 283whp/302wtq @10.5 AFR factory tune. With these cams, JLT II, and O/R X the car put down 330whp/325wtq. With the addition of the FRPP manifold and Long Tubes the car made 363/321wtq.
On the final build I also had the VCT "tune locked" as in the cam timing tables were all "0" and the car made 347whp. With the max cam timing being 17, it puts down 363. So a 16whp difference from phasers being allowed up to 17 degrees retard.
The '01 GT should have put down 300-320 by my assumption, and around the same torque. Obviously, it fell far short of that, and we can't figure out why. It barely makes a bolt-on 2v's power, and less torque. Tuner went through everything he could think of, maxed the spark advance 'til it didn't make any more power, AFR was tits on 12.8. There was nothing more he could tune for, and everything was working properly. We even tested the dyno to make sure it was accurate, it too was bang on.
The car's powerband pulls to 6200 at crest, as it should with these cams/manifold in combo. Even the hp/tq balance is as expected. Just the entire powerband is down on power by at least 30-50hp/tq by all rights.
We took the car on a street romping for further testing. The engine sounds like it's struggling, even "feels" like it's struggling to make power. It's like the engine is screaming, but the power's just not coming out. Hard to explain. All I can say, is it doesn't sound right, compared to the sound of my 3v. I understand the purpose of VCT and it's advantages in efficiency and extending top end power. But we overlayed my dyno runs against the '01 GT's, and it's simply down on power accross the entire curve. In other words, from 2k-5k where I have 0 cam timing, and he's locked out as well, I dwarf his curve in power, even though the curves are identical in slope.
All that said, so far we've covered a compression and leak-down test, both check out good. 145psi is the lowest, 153psi is the highest. Most are right on 150psi. All the valves held 100psi for the leakdown as well. We've inspected the cams/phasers to make sure the right cam is on the right head and what not, just to eliminate all possibilities. Tomorrow we'll be pulling the timing cover and checking chain timing, pulling the followers to make sure they're all true, and even phaser/cam alignment. To be honest I'm completely stumped. This is my build, it's proven already. If he made 300whp/300wtq I might not be so critical about it, at least it's close! Hell, weather could account for even 10whp/wtq, maybe a hair more even. But he's coming in 30-50hp/tq shy, which is considerably under a stock 3v. I'll also be contacting Keith Logan, who has had several successful 3v swaps that yield 300-310whp/320-330wtq with just CAI/LT/OR Pipes/Tune on stock cams locked out. Maybe he knows of something tune-wise, like a mystical check box a tuner is supposed to check or uncheck for 3v swaps(??)
One of our theories was that maybe the 127020's aren't meant to be locked out, and this is the cause of his major lack of power production, since the longblock checks out tight. The problem is, we're running out of cracks to look in for this missing power. It's a lot of power for this combo to not be making. We're contemplating swapping him to stock cams, as most of the other 3v swaps are based, and seeing what happens with his power. But I'd like to have a sound word of confirmation that this would be the correct route to look down, as it doesn't make sense for a stock cam to make bigger gains N/A over an aftermarket cam. The 127020's are by no means a radical cam, but over stock, it's been a major improvement in my build ups, why would locking them prove not only ineffective, but produce power LOSS.
Once we've eliminated the timing chains from being off timing, and cam/follows being true, where the hell do we look next???
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