making boost but power is low
making boost but power is low setup is a 427 lsx twin borg 76/82, holley dominator ecu, i was on the dyno last week and noticed on low boost pulls things seemed ok, as we increased boost additional power per pound of boost was getting to the point of less than 10hp per extra pound. We gapped the plugs down and picked up 120 rwhp so we thought we had spark blowing out. we stopped and i replaced the stock coils with the holley ones and returned today to finish tuning only to find that at the same boost level we stopped at last week we were down power. im not making peak boost till almost 6400 rpm which seems very slow for those turbos to spool. so my question is am i hunting for a boost leak or exhaust leak on the hotside? my logs from the track last week seem to be good as far as converter slippage.
Wouldnt hurt to check for boost leaks and isnt hard to do.
So you gapped the plugs down..picked up power,then went from stock coils to the holley and lost power with nothing else being changed? Why not put the stock coils back on and see if the power is back up, then continue tuning from there?
So you gapped the plugs down..picked up power,then went from stock coils to the holley and lost power with nothing else being changed? Why not put the stock coils back on and see if the power is back up, then continue tuning from there?
Stock coils are a common issue with high boost and holley ECU. It wasn't my current issue but I don't think there's a reason to switch back. Plus it's a big pita on my setup. How can I check the hot side for leaks?
IGN-1A Coil Dwell Hi, the IGN-1A coil you have installed is a 25 AMP coil.
The dwell at boost (GEN IV software) can be 8ms at an 80% duty cycle.
The "cruse" dwell of 3ms is fine.
The Plug Gap can be .065" to 045" for good results.
What SPW ?
Did you use grease ?
You will need LOWER Spark Advance.
You need 35 AMPS for FOUR coils RMS.
What is you Spark Instant ?
Lance
The dwell at boost (GEN IV software) can be 8ms at an 80% duty cycle.
The "cruse" dwell of 3ms is fine.
The Plug Gap can be .065" to 045" for good results.
What SPW ?
Did you use grease ?
You will need LOWER Spark Advance.
You need 35 AMPS for FOUR coils RMS.
What is you Spark Instant ?
Lance
wow, hell of a lot bigger gap than i was thinking, i run a peak of 22 degrees timing, inductive delay was set at 1.0 do I need larger wiring for the coils to the holley? i dont know what spark instant is, dont see it anywhere
Could be hundred different things. The guys I know pushing the Holleys with 585's or similar run tiny gaps... talking like .015 at typical 1000ish hp builds. Start low, work your way up, should be a pretty easy test. What gaps were you running?
Do you have a back pressure rig setup?
Pre/post IC pressures?
Cranking compression?
Who setup the cam? did they degree it?
Do you have a back pressure rig setup?
Pre/post IC pressures?
Cranking compression?
Who setup the cam? did they degree it?
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Kind of random...but just a thought...Are you SURE that the ignition timing you are commanding is ACTUALLY what the engine is seeing? Only way I could see this happening is a crank position trigger wheel being installed incorrectly on the crank, maybe a bad sensor or the settings in Holley are incorrect (I have no experience with Holley EFI, I would think you just select from a drop down menu).
Basically I would just make sure your hardware/sensors/wiring is performing as it should. Are you logging EGT's by chance?
Another thing to consider is cam timing. Did you index the camshaft? It could be retarded a tooth. Depending on your cam specs, you could go there without piston to valve interference and not know it. I would suspect it is retarded a full tooth if it were the case.
Basically I would just make sure your hardware/sensors/wiring is performing as it should. Are you logging EGT's by chance?
Another thing to consider is cam timing. Did you index the camshaft? It could be retarded a tooth. Depending on your cam specs, you could go there without piston to valve interference and not know it. I would suspect it is retarded a full tooth if it were the case.
Check you intake air temps. Higher temps cause the ecm to pull timing. I had a truck I was tuning the other day and it would get full boost but pull 9 degrees of timing because if 172f iat
This is the question I was going to ask. When you log, what are your IAT's and your spark advance at peak IAT's?
I was tuning my E85 turbo Z28 last week. Since I'd read with E85 you don't have to have an Intercooler, I bypassed my FMIC and just went from the Turbo outlet to the Throttebody. Well, In testing it up to 17psi, my IAT's were up to 217 degrees and it pulled the spark advance back to 8 degrees. I could tell that the performance at 17psi (and wide band at .707 lambda, zero knock retard) was 'flat' and unimpressive. I've now gone back to my welding table and started recreating the cold side to re-incorporate the intercooler. Due to the wet weather, I haven't had a chance to try it all out again.
I was tuning my E85 turbo Z28 last week. Since I'd read with E85 you don't have to have an Intercooler, I bypassed my FMIC and just went from the Turbo outlet to the Throttebody. Well, In testing it up to 17psi, my IAT's were up to 217 degrees and it pulled the spark advance back to 8 degrees. I could tell that the performance at 17psi (and wide band at .707 lambda, zero knock retard) was 'flat' and unimpressive. I've now gone back to my welding table and started recreating the cold side to re-incorporate the intercooler. Due to the wet weather, I haven't had a chance to try it all out again.
TECH Regular
Joined: Sep 2014
Posts: 433
Likes: 0
setup is a 427 lsx twin borg 76/82, holley dominator ecu, i was on the dyno last week and noticed on low boost pulls things seemed ok, as we increased boost additional power per pound of boost was getting to the point of less than 10hp per extra pound. We gapped the plugs down and picked up 120 rwhp so we thought we had spark blowing out. we stopped and i replaced the stock coils with the holley ones and returned today to finish tuning only to find that at the same boost level we stopped at last week we were down power. im not making peak boost till almost 6400 rpm which seems very slow for those turbos to spool. so my question is am i hunting for a boost leak or exhaust leak on the hotside? my logs from the track last week seem to be good as far as converter slippage.
-Ensure/double check that timing isn't being pulled for any reason other than MAP.
-Plug Gap
-Is the converter up to the task
-Valve springs
-Exhaust back pressure. Is this through a short down pipe or through full exhaust?
What specific numbers are we talking? What does the progression or symptoms look like? What exactly is low boost, how much did you add after that and what gain did you see, how much did you add after that and what gain did you see...
What fuel?
What's your target AFR?
What's your observed AFR?
How do you have the timing table set-up?
How much and at what rate does timing get pulled out with increased MAP?
The answer's gotta be in here somewhere
TECH Regular
Joined: Sep 2014
Posts: 433
Likes: 0
This is the question I was going to ask. When you log, what are your IAT's and your spark advance at peak IAT's?
I was tuning my E85 turbo Z28 last week. Since I'd read with E85 you don't have to have an Intercooler, I bypassed my FMIC and just went from the Turbo outlet to the Throttebody. Well, In testing it up to 17psi, my IAT's were up to 217 degrees and it pulled the spark advance back to 8 degrees. I could tell that the performance at 17psi (and wide band at .707 lambda, zero knock retard) was 'flat' and unimpressive. I've now gone back to my welding table and started recreating the cold side to re-incorporate the intercooler. Due to the wet weather, I haven't had a chance to try it all out again.
I was tuning my E85 turbo Z28 last week. Since I'd read with E85 you don't have to have an Intercooler, I bypassed my FMIC and just went from the Turbo outlet to the Throttebody. Well, In testing it up to 17psi, my IAT's were up to 217 degrees and it pulled the spark advance back to 8 degrees. I could tell that the performance at 17psi (and wide band at .707 lambda, zero knock retard) was 'flat' and unimpressive. I've now gone back to my welding table and started recreating the cold side to re-incorporate the intercooler. Due to the wet weather, I haven't had a chance to try it all out again.
Coil Voltage Measurement Hi Lmt, good advice here :
Questions asked above :
1. Max Boost ?
2. Spark Instant = 22 too high ??? Thus fuel used and octane ?
3. MAT at boost WOT ?
4. TW tooth count 24xe or 58x ?
5. Coil Voltage at boost WOT ?
6. TDC Verification ? LS-58x=1.75+ common
NOW for GOOD TECH with regards to SPG
When the Ignition Coil, the case of IGN-1A's, is set correctly it will provide the voltage necessary to conduct current at high cylinder pressure containing the fuel/air.
One common man is Andy Frost, Red Victor, in England with 50+ boost and meth.
He uses a large Spark Plug Gap.
The voltage DROPS to 1/10 that of the Spark Instant during current flow, an item that is referred to as Arc Duration.
The Arc Duration MUST occur for a period of thirty crankshaft degrees (Ricardo Tech) AND if longer this energy IS WASTED.
The Spark Plug GAP effects Arc Duration, too small AND the Arc is LONGER than thirty degrees/too SHORT (CDI) does not allow all the fuel to ignite.
The best SPG for 7000 RPM is .045" to .065" with the IGN-1A coil when dwell is set correctly.
This is OF COURSE with respect to Cylinder Pressure, Burning Rate, Cylinder Mixture Temperature, Rod R/L, etc.
This IS the type of "tech" I provide, a "tech" I provided to Doug Flynn at Holley.
Lance, BTW STATE your Valve Seat Pressure BOTH.
Questions asked above :
1. Max Boost ?
2. Spark Instant = 22 too high ??? Thus fuel used and octane ?
3. MAT at boost WOT ?
4. TW tooth count 24xe or 58x ?
5. Coil Voltage at boost WOT ?
6. TDC Verification ? LS-58x=1.75+ common
NOW for GOOD TECH with regards to SPG
When the Ignition Coil, the case of IGN-1A's, is set correctly it will provide the voltage necessary to conduct current at high cylinder pressure containing the fuel/air.
One common man is Andy Frost, Red Victor, in England with 50+ boost and meth.
He uses a large Spark Plug Gap.
The voltage DROPS to 1/10 that of the Spark Instant during current flow, an item that is referred to as Arc Duration.
The Arc Duration MUST occur for a period of thirty crankshaft degrees (Ricardo Tech) AND if longer this energy IS WASTED.
The Spark Plug GAP effects Arc Duration, too small AND the Arc is LONGER than thirty degrees/too SHORT (CDI) does not allow all the fuel to ignite.
The best SPG for 7000 RPM is .045" to .065" with the IGN-1A coil when dwell is set correctly.
This is OF COURSE with respect to Cylinder Pressure, Burning Rate, Cylinder Mixture Temperature, Rod R/L, etc.
This IS the type of "tech" I provide, a "tech" I provided to Doug Flynn at Holley.
Lance, BTW STATE your Valve Seat Pressure BOTH.
so far 24psi, 22 degrees, e85, plug gap 18, 24x reluctor, battery voltage 14.1 steady, i did notice yesterday when i increased dwell to 6.0 from 5.2 i lost 40 hp. i found that my wiring is way too small for the holley coils at the dwell im trying to run. im fixing that as we speak. iat never got over 89 and that was on back to back pulls. i hear of gaps all over the map with holley coils. afr is dead solid 11.3-11.5. knock sensors turned off. converter looked good on track passes. cam sensor set to single pulse, digital falling, dis on coil
