Nothing in the oil. I replaced the pan this spring and no debris. I can check the lift before I do any part removal. But I will be changing out the cam. I know that this may be unpopular, but my gut says that there is a cam issue, bad lobes, lifters, grind or ??. Fwiw, some may say that it could be the gearvendors overdrive. That was a later addition and the dyno was done before that install as well as many runs at the track. Thanks for all the recommendations. Keep them coming. I hope to learn a lot about what is the actual problem along the way. By checking what is the current status of things before disassembly will allow me to assess what changes have occurred when a new cam is in. Thus far, I will check compression, lift, of course timing again and plugs for proper afr. Will also put a temp gun on all exhaust pipes to be sure I don’t have a dead cylinder. Any other checks?
When good is not enough, Camshaft time again.
- Thread starter Kent mosby
- Start date
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BSB67
Well-Known Member
Looks like the DA on 9/20 was probably 4500’ based on track elevation and Spokane weather.
Did you ever tell us the race weight, including driver of the car?
Did you ever tell us the race weight, including driver of the car?
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PRH
Well-Known Member
I don’t know, but the TQ/hp columns are listed as “STP”(which in SF lingo is j607, unless the columns have been renamed), and based on the fuel flow and bsfc numbers(which look quite good to me) there is a 10% correction being applied.
My recollection is the cam was either a Hughes or Howards.904 design, so about .580”+ lift with a 1.5 rocker.
I don’t recall if that engine used 1.5 pr 1.6.
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BSB67
Well-Known Member
Doesn’t “everyone” use 607?
PRH
Well-Known Member
I think pretty much everyone who isn’t doing testing for oem’s uses j607.
But, there’s probably a few contrarians out there.
But, there’s probably a few contrarians out there.
I don't think you could limit a 408 to 400 #-ft of tq. Small cam, big cam...that stroke makes tq. Mine was over 500 #-ft and that's with an unported Super Victor intake that we all know could not possibly make any tq! And a 512, with its longer arm, will make a bunch more than a 408!
I'm going to ask the OP to keep us all posted as to what he learns. Meanwhile, I'll be
.
I will keep posting along the way. A learning opportunity for me and all.I don't think you could limit a 408 to 400 #-ft of tq. Small cam, big cam...that stroke makes tq. Mine was over 500 #-ft and that's with an unported Super Victor intake that we all know could not possibly make any tq! And a 512, with its longer arm, will make a bunch more than a 408!
I'm going to ask the OP to keep us all posted as to what he learns. Meanwhile, I'll be
PRH
Well-Known Member
That sheet was presented for comparison purposes, and is not the OP’s engine.
The OP’s engine hasn’t been on the dyno……..but the car has been on a chassis dyno, which is where the “400hp” number comes from.
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No.
What are you using and why?
My engine dyno has a depac data acquisition. It has three options for correction factor. Std. j607, Sae J1349 and DIN. I haven't ever used DIN. It is metric correcting to 760mm., dry air and 20 degrees Celsius. J607 (The old standard) corrects to 29.92", dry air and 60 degrees. J1349 (new standard) corrects to 29.53", dry air and 77 degrees.
What I use 90% of the time is J1349. J1349 gives lower numbers than J607. It is a newer version of correction that sae came up with that is supposed to be more accurate. I think there are even newer and or different versions than J1349. I did a deep dive on correction factors some years back so my memory may not serve me well.
Why I use J1349 is because when I got my first dyno this was the advice given me by Depac Dave and other dyno operators who helped me get started. And my own research led me the same direction. First let me say that there is nothing wrong with using J607 and in my opinion either factor is better than no correction factor if you want to be able to compare your own data on different days where conditions may be different.
A correction factor is an number that is multiplied by the power an engine makes if the conditions are not the same as the correction factors std conditions of pressure, humidity and temperature. This corrects the number to how much power it would make in theory if it were on a day when the pressure, humidity and temperature were at the actual standard conditions.
Because this number is a theoretical calculation as to how much difference the power will be changed by the different conditions there is a possibility for error. If there is error it is multiplied by the distance you are from the standard conditions. This is why the closer your correction factor is to zero the more accurate the number is. Unfortunately it can't always be zero so we do the best we can with correction factors. A correction factor that is not perfect will still be closer than no correction at all for the purposes of comparing your own data.
What I use 90% of the time is J1349. J1349 gives lower numbers than J607. It is a newer version of correction that sae came up with that is supposed to be more accurate. I think there are even newer and or different versions than J1349. I did a deep dive on correction factors some years back so my memory may not serve me well.
Why I use J1349 is because when I got my first dyno this was the advice given me by Depac Dave and other dyno operators who helped me get started. And my own research led me the same direction. First let me say that there is nothing wrong with using J607 and in my opinion either factor is better than no correction factor if you want to be able to compare your own data on different days where conditions may be different.
A correction factor is an number that is multiplied by the power an engine makes if the conditions are not the same as the correction factors std conditions of pressure, humidity and temperature. This corrects the number to how much power it would make in theory if it were on a day when the pressure, humidity and temperature were at the actual standard conditions.
Because this number is a theoretical calculation as to how much difference the power will be changed by the different conditions there is a possibility for error. If there is error it is multiplied by the distance you are from the standard conditions. This is why the closer your correction factor is to zero the more accurate the number is. Unfortunately it can't always be zero so we do the best we can with correction factors. A correction factor that is not perfect will still be closer than no correction at all for the purposes of comparing your own data.
I need to look in my software because I believe I have at least three options.
I need to do some digging.
Thanks
BSB67
Well-Known Member
You understand that is why I put it in parentheses, right. Of course not everyone does, and of course that’s why you asked.
But, I believe most do use 607, mostly because if they used 1349, there would be more discussion on it, particularly when the discussion goes to “happy” dynos.
PRH
Well-Known Member
Kent’s engine would make for a good episode of Enginemasters.
Test as is, then throw some parts at it…….see what sticks.
If the Street friendly manners and Sniper EFI weren’t a concern, I’d throw some duration at it and see how it responded to that.
If that worked as hoped, I’m pretty sure the converter would need some attention.
Test as is, then throw some parts at it…….see what sticks.
If the Street friendly manners and Sniper EFI weren’t a concern, I’d throw some duration at it and see how it responded to that.
If that worked as hoped, I’m pretty sure the converter would need some attention.
PRH
Well-Known Member
On a SF dyno, the J1349 data is all there, you’d just have to be looking at/printing that page if you wanted it.
So, as fate would have it, both of my dental assistants are sick. That means that I have no one to assist at work. (Dentist, former precision machinist). So that means that tomorrow I begin the investigation.
My plans for tomorrow.
1. Test all exhaust pipes for temperature to verify no dead cylinders.
During the steps 1-2 some disassembly of motor. Removal of the EFI, valley pan etc. So if there are any checks needed for a running motor, let me know now.
2. Compression check cylinders
3. Check lift on all lifters, intake and exhaust.
4. remove and inspect rockers, rocker arm , inspect springs
5. Remove and inspect spark plugs for burn patterns
Pending time.
6. try to check the lift and duration on the camshaft lobes. May require more disassembly than the day allows. Radiator and timing cover may have to wait until the weekend.
If there are any checks or assessments that I should do along the way, let me know. I will do them and post the info.
Thanks again for all the insight and help
My plans for tomorrow.
1. Test all exhaust pipes for temperature to verify no dead cylinders.
During the steps 1-2 some disassembly of motor. Removal of the EFI, valley pan etc. So if there are any checks needed for a running motor, let me know now.
2. Compression check cylinders
3. Check lift on all lifters, intake and exhaust.
4. remove and inspect rockers, rocker arm , inspect springs
5. Remove and inspect spark plugs for burn patterns
Pending time.
6. try to check the lift and duration on the camshaft lobes. May require more disassembly than the day allows. Radiator and timing cover may have to wait until the weekend.
If there are any checks or assessments that I should do along the way, let me know. I will do them and post the info.
Thanks again for all the insight and help
Also, I saw another great suggestion. Check that it's getting full throttle with the gas pedal.
That is shown in the datalogs. It is good. Pedal down, fully open throttle blades. Thanks
As easy as that is to check, I'd be checking. Kent, SOMETHING is wrong somewhere and the data logs are letting you down THERE.
The datalogs can see afr, fuel rates, timing and many other parameters. What they cannot see is what the cam is asking for. They report if the efi is giving the cam what it wants. My suspicion is that the cam is not asking the right questions. Iykwim. My investigations will check for mechanical discrepancies and/or incompatibility of parts or assembly. There must be a weak link or malfunction somewhere. I am determined to find it. The cam may turn out fine. But since it is the heart of the engine, only a transplant will help. All other corrective measures may be needed and be helpful, but the transplant will determine the fate. We may still need to address the TC among others. Thanks for the help.
TT5.9mag
Two atmospheres are better than one
The sniper has a tps auto set wizard. If that’s been done, then the data log is 100% correct and reads actual throttle opening percentage.
Yeah ok. And OBDII was supposed to be standardized.
Probably you have already checked this , if so disregard the following.
Doesn't the auto set up wizard work like this? With throttle at idle push a button. Open throttle to wide open then push a button. I'm not saying the op has this problem but I can think of a couple of scenarios where this could go wrong. One is if you are using the throttle pedal to set wide open. if the throttle is not opening the blades all the way because it is missadjusted or some other reason then the computer will think the less than wide open position is wide open. Similarly if you are opening the throttle at the throttle and something is preventing it from reaching wot such as linkage hitting the manifold or something else the result will be the same. The computer thinks it is wide open but it's not. Might be best to look down the throttle body and verify that what the computer sees as wot is actually wot. Little time will have to be invested to double check this. I hope your lucky enough that your problem would be this simple to fix. But if you have my luck...
Doesn't the auto set up wizard work like this? With throttle at idle push a button. Open throttle to wide open then push a button. I'm not saying the op has this problem but I can think of a couple of scenarios where this could go wrong. One is if you are using the throttle pedal to set wide open. if the throttle is not opening the blades all the way because it is missadjusted or some other reason then the computer will think the less than wide open position is wide open. Similarly if you are opening the throttle at the throttle and something is preventing it from reaching wot such as linkage hitting the manifold or something else the result will be the same. The computer thinks it is wide open but it's not. Might be best to look down the throttle body and verify that what the computer sees as wot is actually wot. Little time will have to be invested to double check this. I hope your lucky enough that your problem would be this simple to fix. But if you have my luck...
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