Rear mount turbo - Type S
05-04-2015, 09:11 PM
#281
^^^
Excellent post! I have wondered about this myself. I'm starting to tinker with my car again after two years. I seem to recall a difference in timing with VSA on vs off when my car was on the dyno. I will install an Air/Fuel Gauge in the next week or so and hopefully take some readings with VSA on and off through the RPM's. I realize this won't specifically answer the timing question but it will give an idea.
Has anyone else researched this?
Thanks screaminz28
Excellent post! I have wondered about this myself. I'm starting to tinker with my car again after two years. I seem to recall a difference in timing with VSA on vs off when my car was on the dyno. I will install an Air/Fuel Gauge in the next week or so and hopefully take some readings with VSA on and off through the RPM's. I realize this won't specifically answer the timing question but it will give an idea.
Has anyone else researched this?
Thanks screaminz28
05-04-2015, 09:18 PM
#282
Racer
Thread Starter
I started thinking about this blown motor, as well as Uath's over the weekend. I am curious, in both of your cases, did VSA engage a lot, or perhaps shortly before the engines went?
I have been searching for a root cause on these failures, and while some may be content to just say "the motors are weak" I disagree, especially with the popularity of the J's in sandrails, and Honda swaps. It appears that ONLY TL's with stock ECUs are cracking ringlands and blowing up motors.
I can't find any whitepapers or technical info on the VSA system other than it is Honda's TCS combined with a slide control system with a yaw rate sensor. If it retards timing a lot, then adds it back very fast, even if not excessive, could this be contributing to the issue? I know big timing jumps between cells is not good, even if they are technically 'safe' timing values, just the big jump can be dangerous. Something to think about anyways...
Any word from the shop on what all was damaged maddog?
I have been searching for a root cause on these failures, and while some may be content to just say "the motors are weak" I disagree, especially with the popularity of the J's in sandrails, and Honda swaps. It appears that ONLY TL's with stock ECUs are cracking ringlands and blowing up motors.
I can't find any whitepapers or technical info on the VSA system other than it is Honda's TCS combined with a slide control system with a yaw rate sensor. If it retards timing a lot, then adds it back very fast, even if not excessive, could this be contributing to the issue? I know big timing jumps between cells is not good, even if they are technically 'safe' timing values, just the big jump can be dangerous. Something to think about anyways...
Any word from the shop on what all was damaged maddog?
The engine has come out of the TL, I'm waiting for the guys to open it up and inspect it. They were traveling today back from a race. I'm going to bug them about it tomorrow. Stay tuned (pun intended).
05-04-2015, 10:54 PM
#283
The VSA did not come on much more often with the turbo, just WOT in first or second gear once the boost hit over 6-8 psi. I didn't notice VSA kicking in before the CEL for the misfiring cylinder, but damage could have occurred at some point with the VSA kicking in.
The engine has come out of the TL, I'm waiting for the guys to open it up and inspect it. They were traveling today back from a race. I'm going to bug them about it tomorrow. Stay tuned (pun intended).
The engine has come out of the TL, I'm waiting for the guys to open it up and inspect it. They were traveling today back from a race. I'm going to bug them about it tomorrow. Stay tuned (pun intended).
I was cruising on a highway by my house when it happened. While it was possible for me to get the wheels spinning at a higher speed, the conditions had to be just right. That day the road was dry and I had plenty of grip.
But i was guilty of lighting it up from time to time during my drives too and from work. If it works like screaminz says it might, I can see how this would cause it some damage. Combine that with a couple long pulls that get the pistons, that weren't designed for forced induction, good and hot, and the added stress of a higher compression ratio......
But bringing this into light. I dont think ill be doing any spirited driving without turning it off first. Funny enough, my dad was talking with me about it when we were trying to dial in the boost controller.
I wonder if boost cut works in a similar way? would someone bring this to light?
maddog. did you have boost cut turned on, if so how often did you hit it?
05-04-2015, 11:35 PM
#284
Racer
Thread Starter
ok that was funny. lol
I was cruising on a highway by my house when it happened. While it was possible for me to get the wheels spinning at a higher speed, the conditions had to be just right. That day the road was dry and I had plenty of grip.
But i was guilty of lighting it up from time to time during my drives too and from work. If it works like screaminz says it might, I can see how this would cause it some damage. Combine that with a couple long pulls that get the pistons, that weren't designed for forced induction, good and hot, and the added stress of a higher compression ratio......
But bringing this into light. I dont think ill be doing any spirited driving without turning it off first. Funny enough, my dad was talking with me about it when we were trying to dial in the boost controller.
I wonder if boost cut works in a similar way? would someone bring this to light?
maddog. did you have boost cut turned on, if so how often did you hit it?
I was cruising on a highway by my house when it happened. While it was possible for me to get the wheels spinning at a higher speed, the conditions had to be just right. That day the road was dry and I had plenty of grip.
But i was guilty of lighting it up from time to time during my drives too and from work. If it works like screaminz says it might, I can see how this would cause it some damage. Combine that with a couple long pulls that get the pistons, that weren't designed for forced induction, good and hot, and the added stress of a higher compression ratio......
But bringing this into light. I dont think ill be doing any spirited driving without turning it off first. Funny enough, my dad was talking with me about it when we were trying to dial in the boost controller.
I wonder if boost cut works in a similar way? would someone bring this to light?
maddog. did you have boost cut turned on, if so how often did you hit it?
05-05-2015, 06:46 AM
#285
Are you referring to boost cut via FP? It's been so long since I have played with it that I don't recall if it's there, but if the boost solenoid isn't connected to the ECU, why would you enable it?
I started a thread on the Hondata forum to see if they can explain what VSA does. If I don't get a response, I'll try sending a direct email.
I'll let you know if I hear anything.
I started a thread on the Hondata forum to see if they can explain what VSA does. If I don't get a response, I'll try sending a direct email.
I'll let you know if I hear anything.
05-05-2015, 07:32 AM
#286
Senior Moderator
Are you referring to boost cut via FP? It's been so long since I have played with it that I don't recall if it's there, but if the boost solenoid isn't connected to the ECU, why would you enable it?
I started a thread on the Hondata forum to see if they can explain what VSA does. If I don't get a response, I'll try sending a direct email.
I'll let you know if I hear anything.
I started a thread on the Hondata forum to see if they can explain what VSA does. If I don't get a response, I'll try sending a direct email.
I'll let you know if I hear anything.
05-05-2015, 08:01 AM
#287
Are you referring to boost cut via FP? It's been so long since I have played with it that I don't recall if it's there, but if the boost solenoid isn't connected to the ECU, why would you enable it?
I started a thread on the Hondata forum to see if they can explain what VSA does. If I don't get a response, I'll try sending a direct email.
I'll let you know if I hear anything.
I started a thread on the Hondata forum to see if they can explain what VSA does. If I don't get a response, I'll try sending a direct email.
I'll let you know if I hear anything.
The boost cut feature is a on 'overboost protection' method. Think about it in terms of preventing catastrophic engine damage - you have it set to 15 psi and your boost controller malfunctions and tries to run 25 psi - the hondata will not let the car rev past where it makes 15 psi in order to try and save the engine.
05-05-2015, 08:02 AM
#288
Three Wheelin'
Both systems are turned ON/OFF with the same button labeled "VSA". It's just a figure of speech for us.
05-05-2015, 08:04 AM
#289
VSA shouldnt be doing anything. VSA is vehicle stability assist. If anything was to be contributing it would be TCS Traction control system (which uses brakes and ignition/throttle closing/fuel cut to limit wheel spin). VSA should only be activating if it starts to detect a slide which would be many variables from different wheel speeds, steering angle, yaw sensors etc... Simple wheel spin wouldnt/shouldnt be activating VSA (which closes throttle and applies brakes to the necessary wheels to help straighten the vehicle)
I know the VSA is for a slide based on steering angle - but does the traction control only apply brakes and close throttle? If so, then my thought about the retarded and advanced timing is invalid.
I will do some data logging this week to see if I see any timing changes from the traction control system. Do you know for sure if it uses ignition retard and fuel cut for the traction control?
05-05-2015, 08:21 AM
#290
Three Wheelin'
From Honda news:
VEHICLE STABILITY ASSIST™ (VSA®)
The TL is equipped with 4-channel Vehicle Stability Assist™ (VSA®) that helps the driver retain control of the car in the event the vehicle reaches its dynamic traction limits. For example, this may occur through aggressive cornering, encountering ice or dirt on the road, or entering a decreasing-radius corner too fast.
In the event of understeer, the system can apply the inside front and rear brakes to increase yaw, slowing the vehicle and enabling it to complete the turn. Engine torque may also be reduced by coordination of the Drive-by-Wire Throttle System™ and powertrain control module.
The 4-channel system controls all four brakes independently. In the event of oversteer (where the rear tires lose grip), the system can apply the outside front and rear brakes to decrease yaw, slowing the vehicle and enabling it to stay on its intended path.
An indicator light on the instrument panel alerts the driver whenever the VSA system is actively enhancing the vehicle's stability.
The traction control component of VSA uses sensors that monitor each of the wheels and a computer-controlled modulation of engine power and front brakes to help prevent wheel spin when starting out or accelerating. If the sensors detect wheel spin, traction control reduces engine power and applies brake force to the affected wheels. This helps the TL maintain traction during acceleration and helps the driver retain steering control, even when accelerating on slippery surfaces.
A cockpit switch is provided to disable the vehicle stability and traction control aspects of the system while leaving the ABS system fully functional.
DRIVE-BY-WIRE THROTTLE (DBW) CONTROL SYSTEM™
The TL and TL Type-S engines both feature an advanced Drive-by-Wire Throttle System™ technology that eliminates the need for a conventional throttle cable. With the driver's throttle pedal movements interpreted electronically, the precise relationship between pedal movement and throttle butterfly valve opening can be varied to suit the driving conditions. The system monitors various parameters such as pedal position, throttle position, road speed, engine speed and gear position. These inputs are then used to set the moment-to-moment relationship between the pedal position and throttle butterfly opening. By altering the amount of "gain" between the pedal and butterfly valve, significant improvements in drivability, response and fuel efficiency are possible.
The DBW system also allows the Vehicle Stability Assist (VSA) with traction control to be fully integrated with engine function. In the TL Type-S the DBW is programmed to "blip" the throttle during downshifts with the Sequential SportShift automatic transmission for faster and smoother downshifts.
The TL is equipped with 4-channel Vehicle Stability Assist™ (VSA®) that helps the driver retain control of the car in the event the vehicle reaches its dynamic traction limits. For example, this may occur through aggressive cornering, encountering ice or dirt on the road, or entering a decreasing-radius corner too fast.
In the event of understeer, the system can apply the inside front and rear brakes to increase yaw, slowing the vehicle and enabling it to complete the turn. Engine torque may also be reduced by coordination of the Drive-by-Wire Throttle System™ and powertrain control module.
The 4-channel system controls all four brakes independently. In the event of oversteer (where the rear tires lose grip), the system can apply the outside front and rear brakes to decrease yaw, slowing the vehicle and enabling it to stay on its intended path.
An indicator light on the instrument panel alerts the driver whenever the VSA system is actively enhancing the vehicle's stability.
The traction control component of VSA uses sensors that monitor each of the wheels and a computer-controlled modulation of engine power and front brakes to help prevent wheel spin when starting out or accelerating. If the sensors detect wheel spin, traction control reduces engine power and applies brake force to the affected wheels. This helps the TL maintain traction during acceleration and helps the driver retain steering control, even when accelerating on slippery surfaces.
A cockpit switch is provided to disable the vehicle stability and traction control aspects of the system while leaving the ABS system fully functional.
DRIVE-BY-WIRE THROTTLE (DBW) CONTROL SYSTEM™
The TL and TL Type-S engines both feature an advanced Drive-by-Wire Throttle System™ technology that eliminates the need for a conventional throttle cable. With the driver's throttle pedal movements interpreted electronically, the precise relationship between pedal movement and throttle butterfly valve opening can be varied to suit the driving conditions. The system monitors various parameters such as pedal position, throttle position, road speed, engine speed and gear position. These inputs are then used to set the moment-to-moment relationship between the pedal position and throttle butterfly opening. By altering the amount of "gain" between the pedal and butterfly valve, significant improvements in drivability, response and fuel efficiency are possible.
The DBW system also allows the Vehicle Stability Assist (VSA) with traction control to be fully integrated with engine function. In the TL Type-S the DBW is programmed to "blip" the throttle during downshifts with the Sequential SportShift automatic transmission for faster and smoother downshifts.
05-06-2015, 05:32 AM
#291
Without coming off as too much of a smart ass, that doesn't do much other than try and sell me a car. There's very little technical information on the "HOW" instead of just the "WHAT".
In the Hondata forum, they said they typically only see throttle closing, which makes me feel better than reduced ignition timing. They also said the single port heads are very sensitive to timing (which we know) I just don't see how the A2s could be that much 'better' overall.
In the Hondata forum, they said they typically only see throttle closing, which makes me feel better than reduced ignition timing. They also said the single port heads are very sensitive to timing (which we know) I just don't see how the A2s could be that much 'better' overall.
05-06-2015, 08:01 PM
#292
Three Wheelin'
^^. I understand. It was all I could find in the 5mins that I had. Was just trying to show that the systems are tied to engine management, sry I didn't have the actual details, didn't mean to piss anyone off.
05-06-2015, 08:18 PM
#293
Senior Moderator
Without coming off as too much of a smart ass, that doesn't do much other than try and sell me a car. There's very little technical information on the "HOW" instead of just the "WHAT".
In the Hondata forum, they said they typically only see throttle closing, which makes me feel better than reduced ignition timing. They also said the single port heads are very sensitive to timing (which we know) I just don't see how the A2s could be that much 'better' overall.
In the Hondata forum, they said they typically only see throttle closing, which makes me feel better than reduced ignition timing. They also said the single port heads are very sensitive to timing (which we know) I just don't see how the A2s could be that much 'better' overall.
It would be pretty easy to know for sure, just need someone with a live data reader or the torque app and go out and spin the tires and watch the data and see what happens to the timing
05-07-2015, 01:43 AM
#294
One would assume that once the ECU closed throttle it would change the mapping on fuel and timing as it would as if you let off the throttle.
It would be pretty easy to know for sure, just need someone with a live data reader or the torque app and go out and spin the tires and watch the data and see what happens to the timing
It would be pretty easy to know for sure, just need someone with a live data reader or the torque app and go out and spin the tires and watch the data and see what happens to the timing
I plan to do some datalogging this weekend while VSA is engaged. Im hoping for rain to make it easier though.
Hondata did reply on their forum as well and said they've mostly only seen throttle closing, so that's a good sign.
I'm still wondering what the issue is on maddogs engine - I'm hoping it's something as minor as a head gasket, or even a burnt valve. If it is a ringland on a forged assembly, there's something wack, to use a technical term.
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FamilyGuy (05-07-2015)
05-07-2015, 11:03 AM
#295
Racer
Thread Starter
Interesting info about how VSA/TCS works. I'm relieved to see that it most likely wasn't losing traction that blew up my engine...
The guys at SpeedFactory haven't had a chance to dig into the engine yet so I don't have a report on what happened to the engine quite yet. I'll post up any update I get as soon as I hear from them. I'll also try to get over there and take pics of whatever the damage is.
The guys at SpeedFactory haven't had a chance to dig into the engine yet so I don't have a report on what happened to the engine quite yet. I'll post up any update I get as soon as I hear from them. I'll also try to get over there and take pics of whatever the damage is.
05-07-2015, 02:00 PM
#296
Three Wheelin'
It's also possible that one of the new parts was defective from factory and failed 
it does happen sometimes
it does happen sometimes
05-08-2015, 05:04 PM
#297
Racer
Thread Starter
Well, I'm back to stock for the moment, I bought a 70k engine and a base model exhaust so that I can drive my car while the shop looks at what happened to the built engine.
Sounded like they won't have time to investigate for a week or so. I'll update when I have more info on what went wrong.
Sounded like they won't have time to investigate for a week or so. I'll update when I have more info on what went wrong.
05-08-2015, 08:32 PM
#299
Racer
Thread Starter
I chose to go with a known cost - going back to stock - rather than hope it's something small needing repair only to find out the cylinder walls are gouged or something else costly.
Oh well, at least people who are considering modding the Type S in the future can learn from my experience...
Oh well, at least people who are considering modding the Type S in the future can learn from my experience...
05-10-2015, 11:44 PM
#300
Burning Brakes
I logged a little tonight with VSA on and off, I was able to spin in 1st but not in other gears, I was able to see that my clutch is slipping on a longer pull 
The throttle plate would close and some ignition was cut, it went from 23 deg to 12 deg and then back to 23 deg in about a 1/10 th of a second.
The throttle plate would close and some ignition was cut, it went from 23 deg to 12 deg and then back to 23 deg in about a 1/10 th of a second.
05-11-2015, 08:16 AM
#301
Senior Moderator
I logged a little tonight with VSA on and off, I was able to spin in 1st but not in other gears, I was able to see that my clutch is slipping on a longer pull The throttle plate would close and some ignition was cut, it went from 23 deg to 12 deg and then back to 23 deg in about a 1/10 th of a second.
The throttle plate would close and some ignition was cut, it went from 23 deg to 12 deg and then back to 23 deg in about a 1/10 th of a second.
05-23-2015, 03:25 PM
#306
This, surprisingly, is how many factory traction control setups work: by retarding ignition and cutting fuel injector pulse (and closing TB if DBW). The ecu is correctly corresponding that ignition value to a safe AFR based on the MAP reading and engine speed which would pretty much eliminate the possibility of ignition induced knock.
06-05-2015, 08:43 PM
#307
Racer
Thread Starter
Finally got to see the damage to the motor. It was definitely detonation, the back 3 pistons were all melted, the cylinders were cracked in several places. The front 3 cylinders and pistons fared better but they were definitely following the rear bank...
That's it for me, I'm not going to be able to keep dumping money into this project. I need to get a few things removed from the car in the next few weeks.
I'll probably be posting the turbo kit on the black market at the end of the month.
That's it for me, I'm not going to be able to keep dumping money into this project. I need to get a few things removed from the car in the next few weeks.
I'll probably be posting the turbo kit on the black market at the end of the month.
.
06-05-2015, 08:59 PM
#309
Racer
Thread Starter
06-05-2015, 09:25 PM
#310
Safety Car
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I think you said you bought it for 3600 shipped for the kit. I am not sure what you paid for labor. So maybe start at 5-6k would be my guess. It is truly a one of a kind kit. Just not sure what people are willing to pay for it especially since it doesn't have a name brand turbo.
06-05-2015, 09:41 PM
#311
Man that sucks sorry to hear, I think we came close to doing that to our motor it just could not take much boost with our gas and 10.4 compression, I think it will be easy to sell the kit and piston rods there is nothing out there for sale and a lot of interest in boosting, I think a low compression piston is all the kit needs to be both awesome and reliable, Thanks for sharing the project with us, sorry it turned out this way
06-05-2015, 10:46 PM
#312
Do you have any pics of the bores & pistons on each bank?
I'm assuming you were tuning with Hondata but who tuned it?
Any knocks recorded before it failed?
What supporting mods did you have done with the turbo setup (ie fuel system, cooling system, meth injection)?
Sorry to hear about the damage man. Forced induction is definitely live and learn. Just too bad and it's generally at high expense on the learning aspect of it. Lol.
I'm assuming you were tuning with Hondata but who tuned it?
Any knocks recorded before it failed?
What supporting mods did you have done with the turbo setup (ie fuel system, cooling system, meth injection)?
Sorry to hear about the damage man. Forced induction is definitely live and learn. Just too bad and it's generally at high expense on the learning aspect of it. Lol.
06-06-2015, 07:29 AM
#314
Do you have any pics of the bores & pistons on each bank?
I'm assuming you were tuning with Hondata but who tuned it?
Any knocks recorded before it failed?
What supporting mods did you have done with the turbo setup (ie fuel system, cooling system, meth injection)?
Sorry to hear about the damage man. Forced induction is definitely live and learn. Just too bad and it's generally at high expense on the learning aspect of it. Lol.
I'm assuming you were tuning with Hondata but who tuned it?
Any knocks recorded before it failed?
What supporting mods did you have done with the turbo setup (ie fuel system, cooling system, meth injection)?
Sorry to hear about the damage man. Forced induction is definitely live and learn. Just too bad and it's generally at high expense on the learning aspect of it. Lol.
With the destruction being so bad, I'm inclined to think the issue had to be something like a failed injector, fuel pump, or something to cause a massive lean condition - I mean, this is forged pistons. So far, many have tossed the stock motor destructions to just 'weak junk pistons'.
Forged pistons are stronger but not indestructible. I know a lot of morons that blew up built 2JZs and wondered what happened because their tuning was crap.
There definitely has to be a specific reason this happened.
Maddog - I don't recall - what CR did you end up going with?
06-06-2015, 09:18 PM
#315
Racer
Thread Starter
I have PCD's and a stock Cat. If I had to guess from what I saw and have learned so far. I would say that back pressure was the likely culprit, but it's just a guess.
My CR was at 10.5:1
My CR was at 10.5:1
06-09-2015, 07:11 PM
#316
I agree with screaminz28. Excessive back pressure could be one of the causes, but it cant be the only cause.
Do you have a wideband gauge installed. If so what were your a/f readings under boost.
i noticed mine can get funky on a hot day.
Also, did you hear any odd noise under boost.
Our knock sensor doesn't work very well. My engine would make some seriously scary noise but i would pass it off as nothing cause my datalogs wouldn't show any knock during the times i heard them. Until I started getting misfires and lots of blow-by.
A dead end fuel system could also be a problem. even with meth injection. When those steel fuel rails (im guessing they're stock) heat soak and start warming up the gas in them, it could cause vapor lock, or at the very least spit fuel in that is more prone to deto. if you had the meth setup to turn on at say 8-10 lb, it wouldn't help a thing if you are putting hot ass gas in your engine at 6-7 lb which is where my problems would start
the high compression setup doesn't really help either. i like the idea of decent power off boost too, but it does seem to make the engine temperamental.
Do you have a wideband gauge installed. If so what were your a/f readings under boost.
i noticed mine can get funky on a hot day.
Also, did you hear any odd noise under boost.
Our knock sensor doesn't work very well. My engine would make some seriously scary noise but i would pass it off as nothing cause my datalogs wouldn't show any knock during the times i heard them. Until I started getting misfires and lots of blow-by.
A dead end fuel system could also be a problem. even with meth injection. When those steel fuel rails (im guessing they're stock) heat soak and start warming up the gas in them, it could cause vapor lock, or at the very least spit fuel in that is more prone to deto. if you had the meth setup to turn on at say 8-10 lb, it wouldn't help a thing if you are putting hot ass gas in your engine at 6-7 lb which is where my problems would start
the high compression setup doesn't really help either. i like the idea of decent power off boost too, but it does seem to make the engine temperamental.
06-09-2015, 09:02 PM
#317
Racer
Thread Starter
I agree with screaminz28. Excessive back pressure could be one of the causes, but it cant be the only cause.
Do you have a wideband gauge installed. If so what were your a/f readings under boost.
I had a wideband gauge, I never saw the a/f go above the high 11's in boost, but I can't say that I was always watching the gauge
i noticed mine can get funky on a hot day.
Also, did you hear any odd noise under boost.
I never heard any odd noises under boost
Our knock sensor doesn't work very well. My engine would make some seriously scary noise but i would pass it off as nothing cause my datalogs wouldn't show any knock during the times i heard them. Until I started getting misfires and lots of blow-by.
A dead end fuel system could also be a problem. even with meth injection. When those steel fuel rails (im guessing they're stock) heat soak and start warming up the gas in them, it could cause vapor lock, or at the very least spit fuel in that is more prone to deto. if you had the meth setup to turn on at say 8-10 lb, it wouldn't help a thing if you are putting hot ass gas in your engine at 6-7 lb which is where my problems would start
Meth injection started at ~3psi and was at max by ~7psi
the high compression setup doesn't really help either. i like the idea of decent power off boost too, but it does seem to make the engine temperamental.
Do you have a wideband gauge installed. If so what were your a/f readings under boost.
I had a wideband gauge, I never saw the a/f go above the high 11's in boost, but I can't say that I was always watching the gauge
i noticed mine can get funky on a hot day.
Also, did you hear any odd noise under boost.
I never heard any odd noises under boost
Our knock sensor doesn't work very well. My engine would make some seriously scary noise but i would pass it off as nothing cause my datalogs wouldn't show any knock during the times i heard them. Until I started getting misfires and lots of blow-by.
A dead end fuel system could also be a problem. even with meth injection. When those steel fuel rails (im guessing they're stock) heat soak and start warming up the gas in them, it could cause vapor lock, or at the very least spit fuel in that is more prone to deto. if you had the meth setup to turn on at say 8-10 lb, it wouldn't help a thing if you are putting hot ass gas in your engine at 6-7 lb which is where my problems would start
Meth injection started at ~3psi and was at max by ~7psi
the high compression setup doesn't really help either. i like the idea of decent power off boost too, but it does seem to make the engine temperamental.
06-09-2015, 09:26 PM
#318
at about 11.5-11.6 i would start to hear hear some loud knock that the sensors didn't detect. it sounded like a can full of rocks on a paint shaker.
you could have been having the same issue, but with your exhaust running underneath the engine, you wouldn't be able to hear it as clearly.
and like i said it didnt show up on the log.
and timing, how much timing were you running with. under boost i couldn't run anything past 8-10* otherwise i get that can of rocks sound.
another thing worth noting is my timing imbalance 5 and 6 wanted much less timing than the rest of the cylinders.
Last edited by UTAH Type-S; 06-09-2015 at 09:34 PM.
06-09-2015, 09:45 PM
#319
Racer
Thread Starter
how high int the boost did you see your a/f and for how long.
at about 11.5-11.6 i would start to hear hear some loud knock that the sensors didn't detect. it sounded like a can full of rocks on a paint shaker.
you could have been having the same issue, but with your exhaust running underneath the engine, you wouldn't be able to hear it as clearly.
and like i said it didnt show up on the log.
and timing, how much timing were you running with. under boost i couldn't run anything past 8-10* otherwise i get that can of rocks sound.
another thing worth noting is my timing imbalance 5 and 6 wanted much less timing than the rest of the cylinders.
at about 11.5-11.6 i would start to hear hear some loud knock that the sensors didn't detect. it sounded like a can full of rocks on a paint shaker.
you could have been having the same issue, but with your exhaust running underneath the engine, you wouldn't be able to hear it as clearly.
and like i said it didnt show up on the log.
and timing, how much timing were you running with. under boost i couldn't run anything past 8-10* otherwise i get that can of rocks sound.
another thing worth noting is my timing imbalance 5 and 6 wanted much less timing than the rest of the cylinders.
06-10-2015, 11:19 AM
#320
Three Wheelin'
iTrader: (3)
This is crazy guys. I never (personally) had a bit of knock on 93 octane, without meth, and at 15 degrees of timing on a stock j35a8 (j32a2 headswapped) 11:1CR centrifugal supercharged motor. I've also never had knock when or sleeved/built as I sit now @ 10:1CR. With E85 I could push it to 18 degrees, still without a sign of knock. Also never had knock on a 250shot of nitrous on a stock j35a8 bottom end.
To clarify, i'm not saying a stock bottom end will last, but just for sake of comparison regarding occurrences of knock.
The one difference here is that I haven't run a turbo yet on a J...but many 1st gen J guys have without any issues increasing timing.
Another thought - Did you check piston to deck height? Maybe you encountered the original problem I did with piston protrusion on my first set of custom Wiseco pistons. I had protrusion of .008! I discoved this during assembly and corrected it. Many wont notice it unless you're looking for it. Maybe the piston is slapping the head with rod grow? Rod grow can get pretty crazy in itself.
To clarify, i'm not saying a stock bottom end will last, but just for sake of comparison regarding occurrences of knock.
The one difference here is that I haven't run a turbo yet on a J...but many 1st gen J guys have without any issues increasing timing.
Another thought - Did you check piston to deck height? Maybe you encountered the original problem I did with piston protrusion on my first set of custom Wiseco pistons. I had protrusion of .008! I discoved this during assembly and corrected it. Many wont notice it unless you're looking for it. Maybe the piston is slapping the head with rod grow? Rod grow can get pretty crazy in itself.