Finally dyno'd the car.
11-24-2013, 12:04 PM
#43
FYI, here's what the graph looks like in STD correction:
765/706 has a nice ring to it.
11-24-2013, 03:01 PM
#49
TECH Enthusiast
First thing I would check on it nosing over up top is whatever inlet hat/filter setup you have on the blower.... Before you try anything else, take that thing off and dyno it with just the open blower.... You will be quite surprised at what it will do..... You'll gain power and it will hold on much better...
For reference, here is my dyno chart. The lower HP pull is with the 4" air inlet with a 90* bend and a filter on it.... Notice it has a crappy boost curve and it drops power like a stone up top.
The only difference between those two pulls is one was thru the 4" inlet/filter and the other was with a velocity stack on the blower, no filter.
4" / 90* inlet with oval filter
V-stack
So if your air hat or air inlet assembly as restrictive as apparently my 4" inlet was, that would be the very first thing I would check.
I have since shortened my air inlet filter, cut most of the bend out of it and used a DP big mouth filter. I think I reduced the restriction by about half..based on what I see on the logs.
1)Look at your air filter setup and test without it.
2)Datalog without it and let us see the Kpa curve up top, then we can determine if the belt is slipping.
I'm pretty sure your problem is in the air filter setup... But with that being said, it still may not peak as high in the RPMs as you would think... I bet it will peak and hold on for a bit before it noses over... But it will still nose over eventually... Especially if youre still running an LS6 intake. (Which I am)...I believe that's one reason why the FI setups peak at 6500 or less and just hold on, then nose over... Rarely will they peak at 6800-7000 and hold on from there... Unless its under 700 hp or something.
For reference, here is my dyno chart. The lower HP pull is with the 4" air inlet with a 90* bend and a filter on it.... Notice it has a crappy boost curve and it drops power like a stone up top.
The only difference between those two pulls is one was thru the 4" inlet/filter and the other was with a velocity stack on the blower, no filter.
4" / 90* inlet with oval filter
V-stack
So if your air hat or air inlet assembly as restrictive as apparently my 4" inlet was, that would be the very first thing I would check.
I have since shortened my air inlet filter, cut most of the bend out of it and used a DP big mouth filter. I think I reduced the restriction by about half..based on what I see on the logs.
1)Look at your air filter setup and test without it.
2)Datalog without it and let us see the Kpa curve up top, then we can determine if the belt is slipping.
I'm pretty sure your problem is in the air filter setup... But with that being said, it still may not peak as high in the RPMs as you would think... I bet it will peak and hold on for a bit before it noses over... But it will still nose over eventually... Especially if youre still running an LS6 intake. (Which I am)...I believe that's one reason why the FI setups peak at 6500 or less and just hold on, then nose over... Rarely will they peak at 6800-7000 and hold on from there... Unless its under 700 hp or something.
11-24-2013, 03:09 PM
#50
TECH Enthusiast
Oh and on your HPT log screen shot, put the pointer over the peak power/rpms and save the screen shot there so the data pulls over to the legend on the left side. I can't tell **** by looking at your chart with no numbers on it... The data in your legend is obviously with the pointer somewhere before the pull started.
A D1sc will make a solid 800rwhp when maxed out so yours isn't quite maxed out yet.... 8" balancer and 3.4" pulley and spin it to 6800 or so will put it slightly past max impeller speed but that will get you the max power out of one. You'll probably see 18-19 psi on your combo with it maxed out... 93 oct/M15&M10 nozzle meth and 15* timing and you'll make 800 rwhp pretty easily...
A D1sc will make a solid 800rwhp when maxed out so yours isn't quite maxed out yet.... 8" balancer and 3.4" pulley and spin it to 6800 or so will put it slightly past max impeller speed but that will get you the max power out of one. You'll probably see 18-19 psi on your combo with it maxed out... 93 oct/M15&M10 nozzle meth and 15* timing and you'll make 800 rwhp pretty easily...
11-24-2013, 03:55 PM
#52
Oh and on your HPT log screen shot, put the pointer over the peak power/rpms and save the screen shot there so the data pulls over to the legend on the left side. I can't tell **** by looking at your chart with no numbers on it... The data in your legend is obviously with the pointer somewhere before the pull started.
A D1sc will make a solid 800rwhp when maxed out so yours isn't quite maxed out yet.... 8" balancer and 3.4" pulley and spin it to 6800 or so will put it slightly past max impeller speed but that will get you the max power out of one. You'll probably see 18-19 psi on your combo with it maxed out... 93 oct/M15&M10 nozzle meth and 15* timing and you'll make 800 rwhp pretty easily...
A D1sc will make a solid 800rwhp when maxed out so yours isn't quite maxed out yet.... 8" balancer and 3.4" pulley and spin it to 6800 or so will put it slightly past max impeller speed but that will get you the max power out of one. You'll probably see 18-19 psi on your combo with it maxed out... 93 oct/M15&M10 nozzle meth and 15* timing and you'll make 800 rwhp pretty easily...
Here's the data... I forgot to move the cursor.
It's weird, I was getting this phantom knock at 4200-4600 at like 0.5-0.7, but you can see the afr is rich, and the timing is way conservative.
Gears are 3.73s and I have the truck inlet hat with a monster 10" filter on the end, or whatever the largest that Bob sells.
11-24-2013, 04:24 PM
#55
Needs more exhaust duration IMHO. It would carry the power past 5500rpm you're losing right now.
Because torque peaks at such a high piston speed, you're moving a very high amount of exhaust volume at 5500rpm. This creates less effective time for the exhaust port to evacuate the cylinder. Combined with your headers and exhaust system, you can see where this is headed.
I would keep overlap roughly the same as it is now, but extend exhaust duration and widen the exhaust centerline.
Your numbers are very good though and I wouldn't be upset with them at all! Especially building the engine yourself!
Because torque peaks at such a high piston speed, you're moving a very high amount of exhaust volume at 5500rpm. This creates less effective time for the exhaust port to evacuate the cylinder. Combined with your headers and exhaust system, you can see where this is headed.
I would keep overlap roughly the same as it is now, but extend exhaust duration and widen the exhaust centerline.
Your numbers are very good though and I wouldn't be upset with them at all! Especially building the engine yourself!
11-24-2013, 05:21 PM
#56
TECH Enthusiast
I hear what you're saying. Unfortunately, because of the location of the blower, the truck inlet hat is the best we have, and it's far from being the most efficient.
Here's the data... I forgot to move the cursor.
It's weird, I was getting this phantom knock at 4200-4600 at like 0.5-0.7, but you can see the afr is rich, and the timing is way conservative.
Gears are 3.73s and I have the truck inlet hat with a monster 10" filter on the end, or whatever the largest that Bob sells.
Here's the data... I forgot to move the cursor.
It's weird, I was getting this phantom knock at 4200-4600 at like 0.5-0.7, but you can see the afr is rich, and the timing is way conservative.
Gears are 3.73s and I have the truck inlet hat with a monster 10" filter on the end, or whatever the largest that Bob sells.
All in all, Id say it looks pretty damn decent and very safe, but you definitely have more power in it just from tuning it a bit up top. And I hear ya on the air hat being the only option...Sometimes you have to make do with what you have... But before becoming too concerned about the high rpm power drop or even gaining more power, you have to pull that hat off and make a pull to see what youre REALLY making...
You have a very solid setup with what you have... Drive/race/enjoy it and when youre bored in 6 months, start tweaking...
Congrats on the build!
11-24-2013, 05:35 PM
#57
Needs more exhaust duration IMHO. It would carry the power past 5500rpm you're losing right now.
Because torque peaks at such a high piston speed, you're moving a very high amount of exhaust volume at 5500rpm. This creates less effective time for the exhaust port to evacuate the cylinder. Combined with your headers and exhaust system, you can see where this is headed.
I would keep overlap roughly the same as it is now, but extend exhaust duration and widen the exhaust centerline.
Your numbers are very good though and I wouldn't be upset with them at all! Especially building the engine yourself!
Because torque peaks at such a high piston speed, you're moving a very high amount of exhaust volume at 5500rpm. This creates less effective time for the exhaust port to evacuate the cylinder. Combined with your headers and exhaust system, you can see where this is headed.
I would keep overlap roughly the same as it is now, but extend exhaust duration and widen the exhaust centerline.
Your numbers are very good though and I wouldn't be upset with them at all! Especially building the engine yourself!
I'm quite pleased with the results, but you always second guess yourself after a dyno. It's one of the reasons I never planned on dyno'ing it because it's a fun street car, so the power level really didn't matter to me, but the scientist in me now has data, and I scrutinize data to the n'th degree.
11-24-2013, 08:04 PM
#59
Alchemist, I think you are extremely extremely rich. 10.2 leaves a lot more power on the table. I understand the safe approach, but go up to at least 10.8-11.0 or so. I bet there is is 50 hp in a afr tweak and possible 1 degree of timing. Regardless, the power its making is damn fun and dynoing it only makes you want more, lol.
