Engine is Toast !!!! Feel my Pain!!
#121
Banned
iTrader: (28)
Joined: Dec 2005
Posts: 5,510
Likes: 0
Received 0 Likes
on
0 Posts
From: Spotswood NJ
Originally Posted by taurran
I'm referring to earlier in the thread when Sharif said he dialed back timing on Jet's car because it was knocking. I'm still truthfully interested in why this had to be done, and how it's related to backpressure not allowing for the turbo to flow properly into the high rpms.
Originally Posted by taurran
The only thing I can think of is he was suggesting that the backressure generated heat which generated knock. Have you found this to be the case on your cars?
Try dataloging the Air intake temps on a TT car compared to a TN car.
#123
Registered User
iTrader: (2)
Joined: Jan 2004
Posts: 1,331
Likes: 0
Received 0 Likes
on
0 Posts
From: NW Ohio
Originally Posted by Sharif@Forged
Jermey, I will let your discription at what happened at ZDAYZ pass, but we all know that isnt what happened....not even close.
#124
Registered User
iTrader: (18)
Joined: Oct 2004
Posts: 9,482
Likes: 0
Received 0 Likes
on
0 Posts
From: .
Originally Posted by MRC Motorsports
back pressure on a FI car can lead to raised EGT's, Which can lead to knock.
Yes,
Try dataloging the Air intake temps on a TT car compared to a TN car.
Yes,
Try dataloging the Air intake temps on a TT car compared to a TN car.
For what it's worth, my car runs quite cool under the hood. Then again, I'm trapping all that heat in the pipes with header wrap, high temp coating, and the turbo blanket.
The only part of the intake tract that gets any warmer than the rest of the car is the intake pipe where it bolts to the timing cover of the motor. I've been trying to imagine how to change this and bolt it down elsewhere, but it's a tight fit in there and VERY close to moving belts. If not for that bolt, the intake charge pipe would be nice and cool.
Oh well, back to the original subject..
#126
Registered User
iTrader: (18)
Joined: Oct 2004
Posts: 9,482
Likes: 0
Received 0 Likes
on
0 Posts
From: .
Originally Posted by merlin3
props to julian for taking an unbiased opinion and helping
#127
Banned
iTrader: (28)
Joined: Dec 2005
Posts: 5,510
Likes: 0
Received 0 Likes
on
0 Posts
From: Spotswood NJ
Originally Posted by taurran
I wasn't as concerned with the intake temps compared to the EGT's in this case.
For what it's worth, my car runs quite cool under the hood. Then again, I'm trapping all that heat in the pipes with header wrap, high temp coating, and the turbo blanket.
The only part of the intake tract that gets any warmer than the rest of the car is the intake pipe where it bolts to the timing cover of the motor. I've been trying to imagine how to change this and bolt it down elsewhere, but it's a tight fit in there and VERY close to moving belts. If not for that bolt, the intake charge pipe would be nice and cool.
Oh well, back to the original subject..
For what it's worth, my car runs quite cool under the hood. Then again, I'm trapping all that heat in the pipes with header wrap, high temp coating, and the turbo blanket.
The only part of the intake tract that gets any warmer than the rest of the car is the intake pipe where it bolts to the timing cover of the motor. I've been trying to imagine how to change this and bolt it down elsewhere, but it's a tight fit in there and VERY close to moving belts. If not for that bolt, the intake charge pipe would be nice and cool.
Oh well, back to the original subject..
You intake temps are probably more critical than EGT's.Thats the whole point for using an intercooler on a F/I car. The cooler the "intake charge" the denser the air,and less prone to detonation,which allows one to run more timing for more power. The higher the intake temps,the less dense the air,the hotter air is more prone to dtonation and pre-ignition,resulting in knock and higher EGT's. This would explain the inability to run lots of timing advance on the TN kits.
They go hand and hand when tuning a car. But the lower the Intake temps, the better...
#128
Registered User
iTrader: (18)
Joined: Oct 2004
Posts: 9,482
Likes: 0
Received 0 Likes
on
0 Posts
From: .
Originally Posted by MRC Motorsports
Are you for real?
You intake temps are probably more critical than EGT's.Thats the whole point for using an intercooler on a F/I car. The cooler the "intake charge" the denser the air,and less prone to detonation,which allows one to run more timing for more power. The higher the intake temps,the less dense the air,the hooter air is more prone to dtonation and pre-ignition,resulting in knock and higher EGT's.
They go hand and hand when tuning a car. But the lower the Intake temps, the better...
You intake temps are probably more critical than EGT's.Thats the whole point for using an intercooler on a F/I car. The cooler the "intake charge" the denser the air,and less prone to detonation,which allows one to run more timing for more power. The higher the intake temps,the less dense the air,the hooter air is more prone to dtonation and pre-ignition,resulting in knock and higher EGT's.
They go hand and hand when tuning a car. But the lower the Intake temps, the better...
You're getting me wrong here (once again). I was more concerned with the earlier correlation between backpressure and knock, and why this would have been a reason to tune Jet's car in the manner it was. This applies to others on this forum and might be a good bit of info. However, it's all heresay and I don't think I'll find out until we tune first hand.
#129
Banned
iTrader: (28)
Joined: Dec 2005
Posts: 5,510
Likes: 0
Received 0 Likes
on
0 Posts
From: Spotswood NJ
Originally Posted by taurran
I know how a cool intake charge allows for more power, thanks.
You're getting me wrong here (once again). I was more concerned with the earlier correlation between backpressure and knock, and why this would have been a reason to tune Jet's car in the manner it was. This applies to others on this forum and might be a good bit of info. However, it's all heresay and I don't think I'll find out until we tune first hand.
You're getting me wrong here (once again). I was more concerned with the earlier correlation between backpressure and knock, and why this would have been a reason to tune Jet's car in the manner it was. This applies to others on this forum and might be a good bit of info. However, it's all heresay and I don't think I'll find out until we tune first hand.
#131
Registered User
iTrader: (3)
Joined: Jul 2003
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
From: Escondido
Originally Posted by MRC Motorsports
Jeremy,
Im not taking sides here..However I just wanted to point out the fact that Sharif's timing maps are actually on par with a Turbonetics on a built motor running 14 psi of "HOT AIR" boost... Trust me, tuning a TN kit on a built motor is a big waste of time IMHO.The kit is designed for 7-8 psi, and thats all its good for in my experience. (Sorry Miaplaya ) The design of the piping and routing of lines make it unfavorable for high boost levels without running inot raised intake air temps.
For example, my average Air intake temp on a Greddy TT kit on the dyno is about 31-35 dgrees celcius. COmparing to any TN kit stock or built, we see an average of 41-46 degrees celcius. This is a HUGE difference.
Once again, I honestly am not taking Sharif's side on this, just pointing out some obvious , legititmate facts.
Im not taking sides here..However I just wanted to point out the fact that Sharif's timing maps are actually on par with a Turbonetics on a built motor running 14 psi of "HOT AIR" boost... Trust me, tuning a TN kit on a built motor is a big waste of time IMHO.The kit is designed for 7-8 psi, and thats all its good for in my experience. (Sorry Miaplaya ) The design of the piping and routing of lines make it unfavorable for high boost levels without running inot raised intake air temps.
For example, my average Air intake temp on a Greddy TT kit on the dyno is about 31-35 dgrees celcius. COmparing to any TN kit stock or built, we see an average of 41-46 degrees celcius. This is a HUGE difference.
Once again, I honestly am not taking Sharif's side on this, just pointing out some obvious , legititmate facts.
Compressor blowing "hot air" aka out of its efficiency range. Lets assume the ambient pressure is 14.7:1. This should be close to accurate being that Jet is in South/Central Florida and most of Florida is below sea level anyways. This is the compressor map for the 60-1 compressor wheel found in the 350Z Turbonetics kit:
Assuming an ambient pressure of 14.7:1 at 14 PSI the pressure ratio would be roughly 1.95. Plotting that on the compressor chart puts us in the last band of the island at 550 Crank HP (roughly based on 55 lb/min of air flow). Jet's car was making about 460 WHP with an added 15 % for drivetrain loss we see that we are even a little bit closer to the center of the island and in the second outermost band of efficiency. What does this all mean? Well the compressor is reaching the limit of efficient air flow it can provide at that pressure ratio with that amount of required air flow. Rasing boost to 16 PSI we would se similar power but more squarely in that band of efficiency. My take is that on this car and this motor the 60-1 compressor should be more then capable of flowing its full 57 lb/min within the efficiency band assuming the Ve of the motor is decent (VQ35 is has over 100% Ve) and the tuning is set this way. Again I am not disputing what people have done and seen. I wasn't there they were. I can see clearly that it is possible for the compressor to start leaving the efficiency island above 16-18 PSI on THIS motor.
The one item I would like some more clarification on is what deltas could present backpressure sufficient enough to maul the power band as it has been reported on one car but not be a factor on another despite similar exhaust/wastegate setups. For the last time, I'm not questioning anyones ability here I'm just genuinely interested in this as it seems to be an anamoly I can't explain. I won't claim to be an engine expert as I am not but I know enough that backpressure can't be caused by compression.
Last edited by MIAPLAYA; 06-06-2007 at 07:29 AM.
#132
Registered User
iTrader: (18)
Joined: Oct 2004
Posts: 9,482
Likes: 0
Received 0 Likes
on
0 Posts
From: .
Originally Posted by MRC Motorsports
BACKPRESSURE CAN CAUSE A CAR TO KNOCK... As I have previously stated and explained why.
Get it?
Oh well, at this point I think I'd be better off talking to this pencil lead sitting on the table here. I've gotta run anyway, I'll check in on this later.
#135
Registered User
iTrader: (5)
Joined: Oct 2004
Posts: 1,914
Likes: 0
Received 0 Likes
on
0 Posts
From: On dicks
Originally Posted by MRC Motorsports
BACKPRESSURE CAN CAUSE A CAR TO KNOCK... As I have previously stated and explained why.
+1 backpressure can lead to greater thermal loads.
BTW Julian did you get my pm?
#136
Registered User
iTrader: (5)
Joined: Mar 2006
Posts: 1,528
Likes: 0
Received 0 Likes
on
0 Posts
From: NoVA
All of this is why I'm going to be personally involved in my own build. If something goes wrong, there's nobody to blame...
Everybody f'ks up. No matter what you do to prevent it otherwise. What or who's fault it is at this point is all lost in this BS arguing. Somebody just needs to tear down the engine and find out what the problem really is. Then it's just a matter of fixing it and getting back on the road stronger than before... Unfortunately, taking risks with FI means that you may end up on a losing side of the table. No matter what you do to reduce the risk (i.e. built engines, finding the right shop for tuning / install, etc.) there's always a chance that **** isn't going to work out.
Good luck man.
Everybody f'ks up. No matter what you do to prevent it otherwise. What or who's fault it is at this point is all lost in this BS arguing. Somebody just needs to tear down the engine and find out what the problem really is. Then it's just a matter of fixing it and getting back on the road stronger than before... Unfortunately, taking risks with FI means that you may end up on a losing side of the table. No matter what you do to reduce the risk (i.e. built engines, finding the right shop for tuning / install, etc.) there's always a chance that **** isn't going to work out.
Good luck man.
#137
Banned
iTrader: (28)
Joined: Dec 2005
Posts: 5,510
Likes: 0
Received 0 Likes
on
0 Posts
From: Spotswood NJ
Originally Posted by MIAPLAYA
No need to apologize. If this is your experience so be it.
You and I both know there are long winded technical expenations from an engineers stand point of what something "SHOULD" or "SHOULD NOT" do....And there are REAL WORLD scenarios of what it "actually does".
Your long winded explenation would imply that both myself and Sharif do not know how to tune a TN kit..
YOu know it yourself the 38mm wastegate dump back into the piping causes a restriction as well as causes the kit to notoriously overboost.
#138
Sponsor
Forged Performance
Forged Performance
iTrader: (92)
Mia, you bring up some good points. One thing to remember, is that AJ's car is tuned on a dyno jet. The 2500lb inertia drum results in less taper towards redline (due to the heavy drum free spinning at high speeds), which gives the appearance of powering being made further in the power band.
On our Dyno Dynamics, a constant and linear load is applied to the rollers, so you have a much more precise indication of what is actually happening at higher RPM, once the rollers are spinning at 120mph or more.
And can someone link me to AJ's dyno chart? IIRC, it was really choppy, and all over the place.
On our Dyno Dynamics, a constant and linear load is applied to the rollers, so you have a much more precise indication of what is actually happening at higher RPM, once the rollers are spinning at 120mph or more.
And can someone link me to AJ's dyno chart? IIRC, it was really choppy, and all over the place.
#139
Registered User
iTrader: (3)
Joined: Jul 2003
Posts: 11,373
Likes: 0
Received 0 Likes
on
0 Posts
From: Escondido
Originally Posted by MRC Motorsports
Mia,
You and I both know there are long winded technical expenations from an engineers stand point of what something "SHOULD" or "SHOULD NOT" do....And there are REAL WORLD scenarios of what it "actually does".
Your long winded explenation would imply that both myself and Sharif do not know how to tune a TN kit..
YOu know it yourself the 38mm wastegate dump back into the piping causes a restriction as well as causes the kit to notoriously overboost.
You and I both know there are long winded technical expenations from an engineers stand point of what something "SHOULD" or "SHOULD NOT" do....And there are REAL WORLD scenarios of what it "actually does".
Your long winded explenation would imply that both myself and Sharif do not know how to tune a TN kit..
YOu know it yourself the 38mm wastegate dump back into the piping causes a restriction as well as causes the kit to notoriously overboost.
#140
My350z
iTrader: (48)
i just want to appologize to sharif, sorry for saying anything to discredit you. i am a good honest person and get caught up in this drama sometimes. its all just stupid. sometimes you have to back up and take a look at the whole picture.
we are pretty much the hardcore racing metal militia of the Z community, its got to be the fastest, loudest, lowest thing around, we let our arrogance overtake our professionalism sometimes, nothing good comes from name calling and so forth...
of course we are rival shops, we will just let the cars performance tell from here...
we are pretty much the hardcore racing metal militia of the Z community, its got to be the fastest, loudest, lowest thing around, we let our arrogance overtake our professionalism sometimes, nothing good comes from name calling and so forth...
of course we are rival shops, we will just let the cars performance tell from here...