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so quick history bought the engine used but with a fresh rebuild. I hoped it would last a summer on low boost while i assemble another that was getting machined for over-sized bolts as well as some porting.
setup was as follows
stock s4 turbo block no porting
ffe trigger kit
ms3x
aem smart coils
id 2000 and 1000 injectors
borg warner s360 .88 ar
aem water injection on at 5 psi and 100 at just over 10
tune was setup as per aaron cakes tune which worked for me previously.
that motor leaned out and broke the dowel area under the oil filter. many parts changed after that motor blew before putting in this one.
so my question is could this have been a bad build, bad seals, band tune.
the tune was very rich in and around boost under 11,s at all times and was tuning just under 6 psi.
the triangular tip is the weakest part of the seal, so if there is detonation, it is the first part to break. i can't say i've ever seen all 6 seals broken, did you verify that the trailings were firing correctly? zero the timing?
I have seen this before with factory 2 piece seals , had 2 engines built in same week do similar . Found cause seals were growing too much and braking same as yours . stopped using those seals 7 years ago because the quality is not as good as the earlier 3 piece ones. Now I only use PTS apex seals and have not seen a seal brake since
the triangular tip is the weakest part of the seal, so if there is detonation, it is the first part to break. i can't say i've ever seen all 6 seals broken, did you verify that the trailings were firing correctly? zero the timing?
timing was set to were it should be. leading's and trailing's were in the correct position everything was checked many times also the were all labeled.
Would you beleive the car still ran fairly well considering all the damage anything over 3,000rpm you couldnt even tell there was a problem. only under 3,000rpm then the car shook a bit and the rpm was very jumpy.
does this look funny to anyone my fuel pressure is rising rate(green line) but at 7.5psi (boost is red line) my fuel pressure falls out. i have a aeromotive 340lph intank.
timing was set to were it should be. leading's and trailing's were in the correct position everything was checked many times also the were all labeled.
does this look funny to anyone my fuel pressure is rising rate(green line) but at 7.5psi (boost is red line) my fuel pressure falls out. i have a aeromotive 340lph intank.
did you verify timing with a timing light? its good practice to verify that the computer is doing what you think it is, because its a computer and they sometimes don't.
it sort of looks like the vacuum line to the FPR popped off, but i guess you would have seen that before the apex seals
The Aeromotive 340 NEEDS heavy gauge wire and a relay. We go overkill with 10 gauge direct from the battery. (Not the alternator) It draws a lot of current, something like 15-18 amps at 60psi rail pressure.
I think that I've come to the conclusion that it was to rich and caused the apex seals to skip and break the tips off. Does this seem possible?
nope, if it was, every factory engine would have broken tips, as they all run about that mixture @wot.
the AFR is 10.2 where you have it marked, and then you can plainly see that boost keeps going up, and fuel pressure drops way off, and AFR goes leaner. can't tell how lean it gets, graph isn't marked
according to your log it was your fuel pressure dropping that led to catastrophic events. keep pointing the finger of blame at the engine and keep replacing engines if you want or go over your fuel system again.
what i would do if i were you is do a volume test of the fuel system at 70psi of fuel pressure, since it apparently is falling flat at 60psi it should be very apparent if there is a problem. most likely you lost a hose inside the tank, which is bypassing once it hits a certain pressure. an easy way to verify that is by doing a dead head pressure test.
but what you REALLY need to do is be more careful, you can see the AFRs creeping up but you didn't let off. 3rd gear is easier on the engine, less risk of blowing it up. 4th gear is a longer gear, gives you more time to keep an eye on the figures, i tune in 4th and may sometimes verify in 5th, though not many people ever actually race through 5th gear... but it appears you just stomped on it at 6500RPMs as boost rapidly climbed until your fuel pressure obviously had a large vent of pressure, then AFRs picks up until "pop". start low in RPMs when tuning and do a full RPM sweep, only once you have everything verified can you do block RPM checks. by starting low in the RPMs, say 2500ish you will have more time to step off the throttle in the event anything looks out of place. course it could just be misleading, with no markings on that graph.
but i also have no experience with a megasquirt and now i know why, the filtering of that ECU sucks *****. there's less peaks and valleys in the rocky mountains.
Last edited by RotaryEvolution; 10-02-15 at 05:07 PM.
according to your log it was your fuel pressure dropping that led to catastrophic events. keep pointing the finger of blame at the engine and keep replacing engines if you want or go over your fuel system again.
but i also have no experience with a megasquirt and now i know why, the filtering of that ECU sucks *****. there's less peaks and valleys in the rocky mountains.
i actually installed that pressure transducer this time as i had this odd feeling that it was fuel pressure that blew my last motor but had no proof. as it was my first tune and really first modified car i just blamed my tune. looks like i am learning from my mistakes sadly those two motors and a turbo have been expensive mistakes.
and in megasquirts defense it does have a smoothed fuel pressure for the logs and etc but in the short period of time i was unable to get it to show actual fuel pressure.
a fuel system check will be done i just didnt think a lean condition could blow all 6 seals.
all this information is great guys thanks a lot!
Last edited by Logan Reinisch; 10-02-15 at 06:21 PM.
but i also have no experience with a megasquirt and now i know why, the filtering of that ECU sucks *****. there's less peaks and valleys in the rocky mountains.
I don't know about you but I prefer my data like I prefer my sex. Raw.
Smoothing is for post processing, I want to see the transients and variance as it also gives me some idea as to the general health of whatever component/system I'm inspecting.
I don't know about you but I prefer my data like I prefer my sex. Raw.
Smoothing is for post processing, I want to see the transients and variance as it also gives me some idea as to the general health of whatever component/system I'm inspecting.
i can agree with you there but this appears to be RFI, every single trace had noise in it. if the RPMs can't be collected semi accurately at least, then you're in trouble.
Last edited by RotaryEvolution; 10-03-15 at 06:29 AM.
Fuel pump is fed with 10 gauge or larger from my fuse panel.
Go directly to the battery on its own circuit. Do not use the connections at the fuel sending unit, either, run the fuel pump relay as close to the tank as possible and then run 14 gauge wires straight from the pump to the relay, using a passthrough like this: http://files.miniford.webnode.com/20...bullit%20b.gif
If your fuel pressure is dropping off, that needs to be addressed first. Before anything else. You have enough pump. (I have been using it exclusively for performance installs, I've very familiar with it) The pump you used does NOT tolerate any voltage drop at all. It must see 13-14 volts at the pump. Pump power and voltage at the pump are nonlinear, the ability to keep up with pressure drops DRAMATICALLY with reduced voltage. This is the downside of a high performance pump, they are power hogs and are not tolerant of poor wiring!
There is voltage drop through the pins in a fusebox, there is voltage drop in the pins in the sending unit connector, even when in good shape not 30 year old junk. That is why I say, go straight from the battery through an inline fuse (30a) directly to a relay mounted as near the pump as possible, and make your own passthrough so you bypass the sending unit.
Yes it is a pain to do. Rebuilding engines is more of a pain.
Logan, can you change your axes and post the plot with voltage and fuel pressure together?
Originally Posted by RotaryEvolution
i can agree with you there but this appears to be RFI, every single trace had noise in it. if the RPMs can't be collected semi accurately at least, then you're in trouble.
Fair enough, although, I'm not entirely sure that's any fault of the MS though. After going over some of my logging, with my rather lightweight flywheel, I can more or less see individual cylinders firing in my idle RPM region from the small fluctuations. Granted, it could be noise from the firing but it appears sinusoidal, not triangular, in nature.
IMO, his fluctuations likely have to do with connection to the CAS which is known to be very noisy and difficult to use.
Originally Posted by peejay
If your fuel pressure is dropping off, that needs to be addressed first. Before anything else. You have enough pump. (I have been using it exclusively for performance installs, I've very familiar with it) The pump you used does NOT tolerate any voltage drop at all. It must see 13-14 volts at the pump. Pump power and voltage at the pump are nonlinear, the ability to keep up with pressure drops DRAMATICALLY with reduced voltage. This is the downside of a high performance pump, they are power hogs and are not tolerant of poor wiring!
I'm unsure of the mechanism that the aeromotive 340lph uses but have you considered the walbro 400 units? I chose one specifically because it requires and consumes less power than traditional pumps and is compatible with E85. This is IIRC, it's been a few years since I was looking into pumps.
I'm unsure of the mechanism that the aeromotive 340lph uses but have you considered the walbro 400 units? I chose one specifically because it requires and consumes less power than traditional pumps and is compatible with E85. This is IIRC, it's been a few years since I was looking into pumps.
Flow requires power, and anything that fits in that form factor will be definition be using the same size motor. They are increasing flow by working the motors harder and harder.
One of the forum members did a study on certain fuel pumps with respect to flow changes at various voltages, the numbers are shocking. Like the flow would halve with a 2v drop or something crazy like that.
Flow requires power, and anything that fits in that form factor will be definition be using the same size motor. They are increasing flow by working the motors harder and harder.
One of the forum members did a study on certain fuel pumps with respect to flow changes at various voltages, the numbers are shocking. Like the flow would halve with a 2v drop or something crazy like that.
I am aware of this, hence my comment on mechanism. There are a variety of mechanisms that can be utilized to cause pressure and they can be arranged in a variety of ways with different benefits and drawbacks. IIRC when the walbro 400 first came out it was the only pump that used (again, IIRC, it's been a while) a flow through design and an impeller. As compared to other pumps there was a great deal less inefficiency in the mechanism and thus the power requirements were less with all that implies.
That does seem like an interesting thread though and I'll look it up sooner or later.
Logan, can you change your axes and post the plot with voltage and fuel pressure together?
IMO, his fluctuations likely have to do with connection to the CAS which is known to be very noisy and difficult to use.
I'm unsure of the mechanism that the aeromotive 340lph uses but have you considered the walbro 400 units? I chose one specifically because it requires and consumes less power than traditional pumps and is compatible with E85. This is IIRC, it's been a few years since I was looking into pumps.
i put tps in there too.
i am using a trigger wheel not a cas as i felt that it was just to old.
the rpm is usually a lot smoother i must say. on the other hand i am seriously think a haltech might be in my near but the lack of i/o on the more budget minded ones is not impressive. it could be argued that these two motors weren't cheap either.
the stealth 340 is the turbine pump and i do believe capable of e85.
i will just throw the regulator in some loop and test the components.
As others have said... something wrong with your fuel system. Whether it be a simple voltage too low or an issue with your FPR/filter/hose/whatever I do not know. The duty cycle appears good but the MS doesn't correct for your fuel pressure dropping through the floor. So... charging system and/or fuel system.
BattV (red line in bottom graph) is interesting! It shows a max of 12.6v (!!! That's LOW if the charging system is working! Huge voltage drop somewhere if it is!) and a low of 6.1v, which is curious because I don't see that anywhere on the log. Voltage stays more or less straight line on the graph.
MS voltage is critical. It should ideally be powered up by the same circuit that powers up the fuel injectors. This is because the MS goes off of its internal voltage to determine the injector dead time, since that slope is dependent on voltage at the injector. So the MS needs to see the actual voltage that the injectors are getting. (And needless to say that voltage should be as close to system voltage as possible - if you have a working charging system then you have 1-2 VOLTS of drop at the computer - which is scandalously bad!)
I have relayed computers before to get rid of voltage drops through the OE wiring. There shouldn't be a drop, but when you are dealing with a 30 year old car, it is easier to run a couple wires and relays than it is to replace every single switch and connector in the circuit... assuming you can get them!
09-29-15, 11:10 PM
