Why can't I achive high boost?
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Evolved Member
Joined: Aug 2010
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From: The Universe
All you guys commenting on the 89 knock count.. when have you seen that much knock on your cars?!?!?! I have a 10:1 stroker i've ran at 31psi on 93 @ 12.0:1 and it seems to peg out at 20...
I don't think hes looking at knock sum.. Knock sensors read voltage when the car isnt' knocking.. a great thing called a filter helps it know if its really detonation or not..
if you had a 89 knock count while your car was running it would sound like someone had a coffee can full of rocks and was shaking the holy living **** out of it. If that isn't happening...
I'll help you eliminate the ECU
does it miss any other time other than wide open throttle..
What exactly down to the thousandth are your plugs gapped to. .021 or lower if your on our style ignition and not a DSM style
A CPS that isn't reading at the correct time will cause a **** TON of misfire issues.
How's it start... it start normal?
I don't think hes looking at knock sum.. Knock sensors read voltage when the car isnt' knocking.. a great thing called a filter helps it know if its really detonation or not..
if you had a 89 knock count while your car was running it would sound like someone had a coffee can full of rocks and was shaking the holy living **** out of it. If that isn't happening...
I'll help you eliminate the ECU
does it miss any other time other than wide open throttle..
What exactly down to the thousandth are your plugs gapped to. .021 or lower if your on our style ignition and not a DSM style
A CPS that isn't reading at the correct time will cause a **** TON of misfire issues.
How's it start... it start normal?
Btw what is a CPS and no ive not gap my new plug yet
Knock of 89 is not good, the least I's start with is getting the map looked at. Is it locked or can you make changes via the hand commander? I would remove 2 to 3 deg of ignition via the hand commander if the knock level is that high (downside is you need to do this each time unless you have datalogit).
What have you gapped the plugs to, and do you have means to monitor AFR's?
What have you gapped the plugs to, and do you have means to monitor AFR's?
These people giving you advice have absolutely no idea what they are talking about.
I've added timing to alive misfire issues. Low timing will cause misfire and misfire itself registers as knock..
Questions
What plugs are in the car.
What ignition is mated to what ECU
Things for you to do.
if plugs are above .020 inch re-gap them.
Ensure they are rq'd correctly and the washer has been left on them. 18ft/lbs is spec for my car.
What fuel are you using, how old are the plugs.
Just FYI i started mis-firing tonight 6k miles on these BPR8ES's 33psi. .018gap ~550whp. Ethanol winter blend.
Evolving Member
Joined: Jan 2007
Posts: 198
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From: UK
All you guys commenting on the 89 knock count.. when have you seen that much knock on your cars?!?!?! I have a 10:1 stroker i've ran at 31psi on 93 @ 12.0:1 and it seems to peg out at 20...
I don't think hes looking at knock sum.. Knock sensors read voltage when the car isnt' knocking.. a great thing called a filter helps it know if its really detonation or not..
if you had a 89 knock count while your car was running it would sound like someone had a coffee can full of rocks and was shaking the holy living **** out of it. If that isn't happening...
I don't think hes looking at knock sum.. Knock sensors read voltage when the car isnt' knocking.. a great thing called a filter helps it know if its really detonation or not..
if you had a 89 knock count while your car was running it would sound like someone had a coffee can full of rocks and was shaking the holy living **** out of it. If that isn't happening...
You have to also remember there is no knock control on a PFC, so DET can cause some real damage quickly.
Since your telling me you don't know your exact gap. I'm 99% sure is your plugs.. Heat range 7 copper BP7RES if you can use the evo8 plug will be good for you. .020 is acceptable on a evo8 with stock coils and ~400whp.
I tuned a car lastweek for instance. Set the fuel, mivec, boost... bang it misfired like no other.. asked him his gap he said .027.. regapped to .020 good as new. Car had minor mods TBE, 3port, FMIC, Fuel, Tune..
moral.. stock gap isnt acceptable on a plug with hardly any miles and a evo with hardly any mods.
okay your on a powercommander.
PFC uses a mic without any filters for knock. an EXTREMELY quiet 4g63 will run in the 20's at wide open throttle... THE PFC is recording engine noise not just 6400hz knock. When you launch a car on the limiter on a pfc you'll see 80's without any real detonation. **** if i turn my filters off on my stock knock sensor it will go nuts when theres no real detonation going on.
none the less your car should be under 60 at wide open throttle. I tuned a RX7 on a FPC and it would read 40-45 at cruise and 30 at WOT.
PFC uses a mic without any filters for knock. an EXTREMELY quiet 4g63 will run in the 20's at wide open throttle... THE PFC is recording engine noise not just 6400hz knock. When you launch a car on the limiter on a pfc you'll see 80's without any real detonation. **** if i turn my filters off on my stock knock sensor it will go nuts when theres no real detonation going on.
none the less your car should be under 60 at wide open throttle. I tuned a RX7 on a FPC and it would read 40-45 at cruise and 30 at WOT.
if this is whats in your car.. you know how to fix it now.
Evolving Member
Joined: Jan 2007
Posts: 198
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From: UK
Without running DET cans, how can you possibly say that?
I've seen misfires at various boost levels on Evo's, many of which do not show record as knock sum or knock voltage on the OEM ECU.
Would not disagree the plugs need gapping correctly, but I'd be very weary and keep a close eye on the hand commander data, after all that's what it for.
Take the advice of the guy who's doing the tuning/mapping on what plugs to use, yes BPR7ES are the NGK copper equivilant to the OEM plug even on a V.
I've seen misfires at various boost levels on Evo's, many of which do not show record as knock sum or knock voltage on the OEM ECU.
Would not disagree the plugs need gapping correctly, but I'd be very weary and keep a close eye on the hand commander data, after all that's what it for.
Take the advice of the guy who's doing the tuning/mapping on what plugs to use, yes BPR7ES are the NGK copper equivilant to the OEM plug even on a V.
Without running DET cans, how can you possibly say that?
I've seen misfires at various boost levels on Evo's, many of which do not show record as knock sum or knock voltage on the OEM ECU.
Would not disagree the plugs need gapping correctly, but I'd be very weary and keep a close eye on the hand commander data, after all that's what it for.
Take the advice of the guy who's doing the tuning/mapping on what plugs to use, yes BPR7ES are the NGK copper equivilant to the OEM plug even on a V.
I've seen misfires at various boost levels on Evo's, many of which do not show record as knock sum or knock voltage on the OEM ECU.
Would not disagree the plugs need gapping correctly, but I'd be very weary and keep a close eye on the hand commander data, after all that's what it for.
Take the advice of the guy who's doing the tuning/mapping on what plugs to use, yes BPR7ES are the NGK copper equivilant to the OEM plug even on a V.
Knock rings the block at 6400hz.. The stock filters in the ecu are designed so the car only reacts to 6400hz noise.
His car basically doesn't have a knock sensor.. It has a engine noise sensor. He can put in 5 gallons of VPQ16 and he will still get 80 counts with it misfiring. I'll bet my HTA86 on it.
Theres a reason the Apexi doesn't use the "knock" sensor to correct for what its reading. I promise the noise from his misfire from his spark issues are causing the jump in knock.
I mean cruise on a car 40 counts?!?! really... Add MS109 to the car and NO change...
The knock count is great when tuning though because you can see a rise in engine noise when the threshold is surpassed before the detonation is bad enough to hear with the human ear.
Evolving Member
Joined: Jan 2007
Posts: 198
Likes: 2
From: UK
well first off to the op i wouldn't waste my money on iridium. Just get NGK BPR7ES's less than 8$ a set anywhere but ams
The knock count is great when tuning though because you can see a rise in engine noise when the threshold is surpassed before the detonation is bad enough to hear with the human ear.
The knock count is great when tuning though because you can see a rise in engine noise when the threshold is surpassed before the detonation is bad enough to hear with the human ear.
After having some bad experiences with PFC's I'm always very careful with them, hence always using det cans rather than just releying on the information FC datalogit displays. As said already you can hear a light ping in the cans above a figure of around 65 on the commander.
One other thing to check and becoming a very common issue seen here on the IV to VI is failure of the fuel pump high voltage relay, so the fuel pump does not get higher voltage when required, this gives the same symtoms as the OP describes, hence the initial question of AFR monitoring. Although I'm sure the tuner would see this right away on the wideband.
Thread Starter
Evolved Member
Joined: Aug 2010
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From: The Universe
CPS camshaft position sensor.. I would suspect this if the car has had a recent cam swap.
Since your telling me you don't know your exact gap. I'm 99% sure is your plugs.. Heat range 7 copper BP7RES if you can use the evo8 plug will be good for you. .020 is acceptable on a evo8 with stock coils and ~400whp.
I tuned a car lastweek for instance. Set the fuel, mivec, boost... bang it misfired like no other.. asked him his gap he said .027.. regapped to .020 good as new. Car had minor mods TBE, 3port, FMIC, Fuel, Tune..
moral.. stock gap isnt acceptable on a plug with hardly any miles and a evo with hardly any mods.
Since your telling me you don't know your exact gap. I'm 99% sure is your plugs.. Heat range 7 copper BP7RES if you can use the evo8 plug will be good for you. .020 is acceptable on a evo8 with stock coils and ~400whp.
I tuned a car lastweek for instance. Set the fuel, mivec, boost... bang it misfired like no other.. asked him his gap he said .027.. regapped to .020 good as new. Car had minor mods TBE, 3port, FMIC, Fuel, Tune..
moral.. stock gap isnt acceptable on a plug with hardly any miles and a evo with hardly any mods.
Thanks
If I run 8's i find my car needing new plugs much much sooner. Like 2x a oil change vs every oil change..
Honestly man you prolly don't even need to replace them.. Just remove them and check the gap if its .27 or so take it down to .020 you can go higher later but we want to completely eliminate spark blow out.
If you changed your cams to s2's and didn't re-tune you car may have a lean misfire. thats a big peice of info man. (the cam swap)
If you have not tuned since cam swap. Buy a new set of plugs and head to your tuner.
Don't bother replacing your CAS its fine. I had a customer just install s2's on his own and put his CPS in 180* out and the car had a ton of trouble starting.
Positive your car's in time? And cams are deg'd correctly?
Last edited by CammedEvo; Feb 17, 2011 at 06:03 AM.
Thread Starter
Evolved Member
Joined: Aug 2010
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From: The Universe
If you not gonna try for crazy boost on pumpgas. 7 Heat ranges will idle better and last longer and be more foul resistant.
If I run 8's i find my car needing new plugs much much sooner. Like 2x a oil change vs every oil change..
Honestly man you prolly don't even need to replace them.. Just remove them and check the gap if its .27 or so take it down to .020 you can go higher later but we want to completely eliminate spark blow out.
If you changed your cams to s2's and didn't re-tune you car may have a lean misfire. thats a big peice of info man. (the cam swap)
If you have not tuned since cam swap. Buy a new set of plugs and head to your tuner.
Don't bother replacing your CAS its fine. I had a customer just install s2's on his own and put his CPS in 180* out and the car had a ton of trouble starting.
Positive your car's in time? And cams are deg'd correctly?
If I run 8's i find my car needing new plugs much much sooner. Like 2x a oil change vs every oil change..
Honestly man you prolly don't even need to replace them.. Just remove them and check the gap if its .27 or so take it down to .020 you can go higher later but we want to completely eliminate spark blow out.
If you changed your cams to s2's and didn't re-tune you car may have a lean misfire. thats a big peice of info man. (the cam swap)
If you have not tuned since cam swap. Buy a new set of plugs and head to your tuner.
Don't bother replacing your CAS its fine. I had a customer just install s2's on his own and put his CPS in 180* out and the car had a ton of trouble starting.
Positive your car's in time? And cams are deg'd correctly?
Will update you guys tmr if i manage to see my tuner tmr and try to find out what the real problem was...
Thank you very much for your kind sharing.
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From: The Universe
Hi Guys,
ive not send my car for a remap yet as im tidying my ride such as adding 7 psi spring to my current ultragate 38mm Turbosmart w/g, etc.
But 1 thing i realize when ive a convoy with others Mitsu Evo friends yday nite, my car can hardly exceed 200km/hr as whenever it almost hit 200km/hr the w/g just kept on opening and i got to keep on release a little on the peddle and throttle again and again.
Its dont seems my ride is lack of power in fact i can feel my ride is still pushing for more but the w/g just keep on limiting the speed and im not full boosting all the way.
Any clue?
ive not send my car for a remap yet as im tidying my ride such as adding 7 psi spring to my current ultragate 38mm Turbosmart w/g, etc.
But 1 thing i realize when ive a convoy with others Mitsu Evo friends yday nite, my car can hardly exceed 200km/hr as whenever it almost hit 200km/hr the w/g just kept on opening and i got to keep on release a little on the peddle and throttle again and again.
Its dont seems my ride is lack of power in fact i can feel my ride is still pushing for more but the w/g just keep on limiting the speed and im not full boosting all the way.
Any clue?
Last edited by jameswwt; Feb 18, 2011 at 09:33 PM.