On Fuel Rail Pressure...

Ollie5002

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First you tried to discredit me over the 8k shift. Remember when you called ******** then like 3 posts later Lee and owner of log confirmed it to be true. I’m not going to share anything that won’t hold up in court just in case Ortiz thinks they have a case. I have been truthful about everything I have done in the community.

The log with fuel pressure issues was from a car that would stutter then take awhile to recover WOT due to fuel pressure. That’s a nice long post about how I’m wrong but that car had fuel pressure issues ‍♂️. Why did it stutter then take about 4 seconds to recover? If it was running fine.

These are logs are from real people 802SHO and others. He went on to break the record after switching off the Ortiz sauce, remember that? I’ll be the first to admit I’m no tuner but that doesn’t mean I can’t open up a log and go whoa that’s **** up.

Your educating the wrong guy, I’m not the one selling tunes with fuel pressure issues. It seems like Ortiz they could use someone with your skills collaborating with them.

Are we going to race this year?!?
What others.... Stumpy and Ken... I am trying to u derstand how you have the most built car in here and only went what 11.3 or did you finally get an 11.2
 

ClearwaterSHO

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So I originally wrote this out in the above thread but unbeknownst to me it got locked. Spent too much time to let it vanish, and I think it is important set the record straight and show precisely why listening to anything @DadMobile says is damaging to your brain cells. I personally don't care what tuner anybody chooses. They all have their individual quirks, and people should share their own experiences to help others know what to expect. Trolling around the internet hyperbolically bashing products you've never used, based on incomplete information, shows a complete lack of character. Doing it for personal gain via youtube views takes an extra slimy type of turd. Maybe I'm alone in thinking this, but I feel like the SHO community and the internet in general would be a much better place if such people would just shut up and crawl back into the septic tanks they were born in. Anyway, we now return to our originally scheduled post...


I highlighted the key fact of the above sentence. This guy seriously doesn't even know how to read a log and yet he's out there trying to play tuner expert. In his video he pointed out a fuel pressure dip to 1400 psi [9.92 MPa]. But then a guy mistakenly commented that it was the lpfp and he agreed, saying that "the lpfp shouldn't get that low WOT." Fuel Rear Pressure in Livelink is rail pressure. Has this clown ever even opened his own datalog before??? I doubt it.
View attachment 83910
Really??? lift pump pressure shouldn't be so low as 9.92 MPa?! Wow, that's news to me! Didn't know there was such a capable in-tank pump on the market! What kind of fuel line do I need to install to handle that kind of pressure?? LMAO This just goes to show that he has zero actual interest or understanding of tuning but is just clambering for anything he can sensationalize for clickbait without the slightest idea of what it means.

Now I'm going to waste a shit ton of time trying to educate him. Maybe if I can open his eyes to just how ignorant he really is, it might encourage him to do some self reflection and stop being such an insufferable dou.chenozzle at the expense of peoples' livelihoods. If not, I may at least be able to help others see what an unreliable and irrelevant source of information he is and stop watching him.

Fuel pressure, by itself, means absolutely nothing in comparing tunes. It's really not that effective indicator of a problem on its own, either. If Ortiz runs a flat 0.81 lambda (which he does) and experiences a slight FRP drop, but GH runs more lean with a tapered target of .85 to .82 lambda (which he does) and there is no decline in rail pressure, which one is safer assuming identical airflow? ORTIZ. The richer tune wins. Ortiz runs 3.6% richer for cooler combustion charge temperatures, which puts more load on the HPFP, hence the higher potential for rail pressure dips. But mechanically nothing changes. The capacity of you HPFP is what it is, and pumping greater fuel via lower AFR's does not create a more dangerous situation IN ANY WAY WHATSOEVER.

Gearhead lambda targets:
View attachment 83911

Ortiz lambda target:
View attachment 83912

Both of the above logs are from the same owner/vehicle and same mods. Does this imply that Gearhead is tuning around a problem? I'm sure some will think that, but that is not true either. The reality is that the amount of fuel required to maintain cylinder temperatures is dependent on the amount of heat generated. Lower RPM = less horsepower = less heat generated -> less charge cooling necessary.

"But Stripsho, if my fuel rail pressure dips below setpoint, won't my engine lean out and blow up?!" Well, no, very unlikely.
-First of all, the PCM has built-in protection and will automatically close the throttle if the injector duty cycle approaches maximum.

-Second, rail pressure loss is most common to occur at low to mid RPMs due to HPFP capacity being proportional to engine speed. See my comments in the previous paragraph regarding RPM and effective cooling requirements.

-Third, and corollary to the previous point, max injector pulsewidth (window of injection) is inversely proportional to engine speed. At lower RPM there is more time available to inject fuel, so you do not need as much pressure to meet fuel demands. Look at this log below, 5th chart. You can see me plummet all the way to 900 psi rail pressure yet I'm still only using 82% injector duty cycle at that point. Shortly thereafter, I hit max pulsewidth and stay near max pulsewidth even though rail pressure is increasing AND air load is decreasing. By 5600 RPM I've nearly doubled my rail pressure, load has dropped 15%, but I'm still 95% inj. duty cycle. It's due to the injection window shrinking as well as my progressively lower lambda targets.
View attachment 83913

Oh btw this is from expirimental testing specifically seeking out these limits. I'm swinging for 20 psi and .78 lambda on a stock fuel system. Spare me any criticisms of what you may see.

Now let's dive into some meat and potatoes about the fuel system. Below are some specs and volumetric efficiency table of a stock HPFP.
View attachment 83914
Source: HPTuners Tune Repository, 2013 Taurus SHO stock calibration

WARNING: MATH INCOMING!
The HPFP has a displacement of 0.0171 cubic inches, or 0.0683 cubic inches per cam revolution. Using the provided fuel density 46.82 lb/ft^3, we arrive at a theoretical pump capacity of (0.0683 cu.in/cam rev) * (1 cu.ft/1728 cu.in) * (1 cam rev/2 engine rev) * (46.82 lb/cu.ft) = 0.0009259 lb fuel per engine revolution at 100% volumetric efficiency. V.E. of the pump is inversely proportional to rail pressure, and also varies with RPM as the table and 3d chart illustrate.

Let's use this data to expound on various tuners' lambda target decisions and how this impacts rail pressure. As an illustrative example, let's take an engine operating at 4000 rpm and 1.90 Load, running E10 pump gas with a stoichiometric AFR of 14.1:1. A 3.5L engine displaces 0.00157 lb of standard air per cylinder, per intake stroke. This represents 1.00 Load. So let's multiply this out: (.00157 lb per cylinder load) * (6 cylinders) * (4000 RPM / 2 RPM per intake stroke) * 1.90 Load = 35.80 lb/min mass air flow.

Consider first the GH tune running 0.84 lambda at 4000 rpm. That's 14.1 Stoich * .84 = 11.844 AFR. The required fuel mass flow rate is: (35.80 lb/min airmass) / (11.844 AFR) = 3.02 lb/min fuel flow requirement. Now, we can actually look at the pump data and figure out what rail pressure it is able to sustain at this flow. We need (3.02 lb/min req) / (3.70 lb/min [100% VE]) = .816 or 82% V.E. At 4000 RPM this interpolates to the 2176 psi row of our pump's VE table.

Now let's do the same thing for an Ortiz tune. 0.81 lambda at 4000 rpm = 11.421 AFR. The required fuel mass flow rate is: (35.80 lb/min airmass) / (11.421 AFR) = 3.13 lb/min fuel flow requirement. 3.13/3.70 = .846 or 85% minimum pump VE to sustain flow. This interpolates to a rail pressure capability of 1631 psi.

There you have it. 545 psi difference in rail pressure just by having a 3.6% richer (and therefore safer) fuel target. Not because of running too much boost or any other "mistake". Additionally, the richer lambda setpoint would trigger Insufficient Fuel Flow mode faster in the event of a problem. It is completely illogical and bass ackwards to say an Ortiz tune is dangerous or flawed because of a dip in rail pressure. IT MEANS NOTHING.

Now, since the log in question within his video is an e30 log, I could dive into all the factors with the latent cooling properties of ethanol and the over-the-top margin of safety inherent to the physics of it. But I'm afraid this is where the free lesson ends. Hopefully this has been sufficient to open the eyes of some of you to the intricacies and mechanics of tuning a car and encourages you to not be influenced by irreverent and incompetent attenion wh.ores.
Couldn’t have said it better myself. Bravo
 

yaycandy

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I used to be a mod on a gaming forum way back when. Sometimes its best to let the arguments burn themselfs out before closing a thread. Because they always continue elsewhere. All of them here always burn out pretty quickly anyway. Were all like a tv family on here. At the end were all good until the next episode
 

mattr66

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I'll make this comment on fuel pressure. You may be only dropping to 12 mpa or even lower sustained at WOT, but what happens when you slosh your fuel in the tank hard enough to get a momentary lapse in low pressure fuel. A positive displacement pump at the limit of flow will have a huge drop in capacity when low pressure fuel drops. The injectors depend on either pressure or having the pintle fully seated to keep reverse flow from happing and hanging them open under combustion pressures. I don't like risking the customer's engine for a little extra horsepower. However, on a stock pump car with intercooler and downpipes should be able to make 400 whp on 93 octane on a dynojet or dynojet-calibrated dyno.
 

Ollie5002

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What others.. you said a few others.. let's see the names we know Andrew, not just hear say. Being someone to prove their word has only showed that a few points from the same car.. you get your info from others.. kinda like a wastewater system(usually full of shit) coincidence probably not. Your buddy has no clue about my car actually no one but maybe 3-4 people on what was up with it when I got it..
 

Ollie5002

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I'll make this comment on fuel pressure. You may be only dropping to 12 mpa or even lower sustained at WOT, but what happens when you slosh your fuel in the tank hard enough to get a momentary lapse in low pressure fuel. A positive displacement pump at the limit of flow will have a huge drop in capacity when low pressure fuel drops. The injectors depend on either pressure or having the pintle fully seated to keep reverse flow from happing and hanging them open under combustion pressures. I don't like risking the customer's engine for a little extra horsepower. However, on a stock pump car with intercooler and downpipes should be able to make 400 whp on 93 octane on a dynojet or dynojet-calibrated dyno.
If your fuel is low enough that a slosh will affect it then I would let darwinism take over. But I forget people are after the lowest 11 sec run even if it's only hundredths of a second... microrecords are the most dumb thing ever... but people want to be relevant and act like they did something for the platform.
 

mattr66

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If your fuel is low enough that a slosh will affect it then I would let darwinism take over. But I forget people are after the lowest 11 sec run even if it's only hundredths of a second... microrecords are the most dumb thing ever... but people want to be relevant and act like they did something for the platform.
The bad thing is the tuner always gets blamed so I try to minimize possible scenarios a customer can encounter that would lead to a grenaded engine. Same thing with meth. Dedicated meth tunes can really hurt things if you lose prime or forget to fill the tank. It is great for cooling and fuel flow buffering though.
 

yaycandy

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The bad thing is the tuner always gets blamed so I try to minimize possible scenarios a customer can encounter that would lead to a grenaded engine. Same thing with meth. Dedicated meth tunes can really hurt things if you lose prime or forget to fill the tank. It is great for cooling and fuel flow buffering though.

Nice to see you and Brad are on the same page about meth. Not that he wont tune it for street but he is kinda against it for just street use. He has some storys about people running out and still running the tune thats expecting it to be there lol
 

76FoMoCo

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Nice to see you and Brad are on the same page about meth. Not that he wont tune it for street but he is kinda against it for just street use. He has some storys about people running out and still running the tune thats expecting it to be there lol
Brad will not tune to meth dependent. And this is smart on his part.
Matt I'm happy to see you contribute to the 4ms. Brad will tune to E30 only after many logs. From what I see Matt has chosen to be more conservative and stay out of the many logs needed for E 30 on each car.
 
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SeanDev

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Tune ive had for over a year from Brad, i have dips to 1300psi. He thought i would be ok. No issues at all. I drive like a nut and track the car. I really should get the pump maybe. I asked stripsho about it right away last year. Not distrusting Brad but to get a another TRUSTED opinion and he said he wouldnt bat an eye at it. All has been good

View attachment 83922
Agree, I havnt used another tuner but Brad, and honestly I have no need to. Every upgrade, he updates tune after a log, so far only needed one revision. Man's a wizard.
 
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SeanDev

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Idk, if my return to the sho world was a good idea. Yall still can't drop a subject after the conversation is dead. Someone always gotta have the last say lmao
I saw your YouTube video, was obvious your return was a good idea. Wouldn't be surprised if you spent the night in the car when you got it home.
 

Ollie5002

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The bad thing is the tuner always gets blamed so I try to minimize possible scenarios a customer can encounter that would lead to a grenaded engine. Same thing with meth. Dedicated meth tunes can really hurt things if you lose prime or forget to fill the tank. It is great for cooling and fuel flow buffering though.
If you know the risk you also know what to look for when using meth heavy. Torrie was so good when I was trying out things with the car being not confident with it and changing things up on the meth setup. Luis knows the time and money I have invested and that is part of the reason I haven't done much with it because the hours have burnt me out on the car.. most tuners just say go and do this and don't explain to the new kids, things to watch. Things to monitor, and lastly common sense of the system.. with all these videos of people wanting follows maybe make one on meth and Maintenence.
 

SM105K

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Meth is great for cooling/cleaning, not a fan for aux fueling however. Too many variables that Matt outlined.
 

802SHO

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Meth is great for cooling/cleaning, not a fan for aux fueling however. Too many variables that Matt outlined.
I don’t see how it can only be used for cooling/cleaning only. It’s fuel so it will increase how rich you are. How does running more rich translate to more power? Why wouldn’t a tune accommodate and expect that fuel….so to somewhat need it moving forward. It’s no different than tuning to rely on whatever mod was added.

It’s not just going to stop working. This goes way back to installer error and you get what you pay for when choosing meth kits.
 

SM105K

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I don’t see how it can only be used for cooling/cleaning only. It’s fuel so it will increase how rich you are. How does running more rich translate to more power? Why wouldn’t a tune accommodate and expect that fuel….so to somewhat need it moving forward. It’s no different than tuning to rely on whatever mod was added.

It’s not just going to stop working. This goes way back to installer error and you get what you pay for when choosing meth kits.
That is the difference in my mind. A normal kit for cooling/cleaning and a bump in power is cool. I should probably have one on my car.

However, when you are adding direct port or more nozzles in a attempt to make up for lack of traditional fueling (which isn't you) I don't feel comfortable about it. I know that was common place back in the day because we didn't have upgraded injectors, HPFP, and LPFP. However there really isn't an excuse anymore. If you cant afford at least the upgraded fuel pumps then you shouldn't be wanting to make bigger power. That is when I draw the line. Using a meth kit as a band aid as a aux fuel system is exactly that, a band aid.

Meth is like nitrous to me. There are many variables on how the systems work. Lose a fuel/meth pump, a fuel solenoid fails, ect bad things happen when the tune is completely dependent on that extra fuel to perform correctly. 9 times out of 10 the upgraded fuel pumps will be less expensive then a melted motor when a aux fuel system component fails. I mean I see used pumps going for a grand on FB groups. I was lucky when I got mine for a extremely fair price with extremely low mileage.

However Andrew you are not the average owner. You are different and your goals are different then the average Joe that wants to save some coin and be completely dependent on meth kit.
 

SeanDev

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That is the difference in my mind. A normal kit for cooling/cleaning and a bump in power is cool. I should probably have one on my car.

However, when you are adding direct port or more nozzles in a attempt to make up for lack of traditional fueling (which isn't you) I don't feel comfortable about it. I know that was common place back in the day because we didn't have upgraded injectors, HPFP, and LPFP. However there really isn't an excuse anymore. If you cant afford at least the upgraded fuel pumps then you shouldn't be wanting to make bigger power. That is when I draw the line. Using a meth kit as a band aid as a aux fuel system is exactly that, a band aid.

Meth is like nitrous to me. There are many variables on how the systems work. Lose a fuel/meth pump, a fuel solenoid fails, ect bad things happen when the tune is completely dependent on that extra fuel to perform correctly. 9 times out of 10 the upgraded fuel pumps will be less expensive then a melted motor when a aux fuel system component fails. I mean I see used pumps going for a grand on FB groups. I was lucky when I got mine for a extremely fair price with extremely low mileage.

However Andrew you are not the average owner. You are different and your goals are different then the average Joe that wants to save some coin and be completely dependent on meth kit.
Plus side though like how Brad set up my non dependent AO tune is when the meth hits I get probably a easy 30hp bump, but even with meth off or failure, which I had once, the car reacts instantaneous, no concerns this tune will fail my engine. I have the HPFP and the Deatschwerks DW300C LPFP, and I'm keeping the meth. Cleaning and easy HP with no downside. I'm with you on being dependent, to much of a worry for me. but to each their own.
 

Bluezone

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I dunno. For me personally I just can't wrap my head around upgrading my pump as a solitary upgrade. The car is happy with e40 as is. And yes I do technically have a small amount of boost left on the table, but you SCT guys don't get to log turbo speed. 220,000 RPM inferred speed is fairly common to see, and I don't know if I'm comfortable pushing the stock snails any harder than that. I imagine a dual intake kit would help a lot in that regard. The other part of it is that when I have the timing set to YES, PLEASE! I actually lose enough exhaust energy to have a reduction in boost potential. My car makes more boost on a hot summer day with pump gas than it can make on a cold october night with C40.
Yeah I noticed the same thing with cold days. The air density, when it's cold, really works over the turbos.
 

stripSHO

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First you tried to discredit me over the 8k shift. Remember when you called ******** then like 3 posts later Lee and owner of log confirmed it to be true. I’m not going to share anything that won’t hold up in court just in case Ortiz thinks they have a case. I have been truthful about everything I have done in the community.

The log with fuel pressure issues was from a car that would stutter then take awhile to recover WOT due to fuel pressure. That’s a nice long post about how I’m wrong but that car had fuel pressure issues ‍♂️. Why did it stutter then take about 4 seconds to recover? If it was running fine.

These are logs are from real people 802SHO and others. He went on to break the record after switching off the Ortiz sauce, remember that? I’ll be the first to admit I’m no tuner but that doesn’t mean I can’t open up a log and go whoa that’s **** up.

Your educating the wrong guy, I’m not the one selling tunes with fuel pressure issues. It seems like Ortiz they could use someone with your skills collaborating with them.

Are we going to race this year?!?
Yeah sure, you can open a log and say "whoa that's ****** up" but saying it doesn't make it so. Show me where the car leans out, show us in the MPH trend where it stops accelerating, or show us any sign of misfires. Then tell us all the troubleshooting steps you and mystery owner went through to rule out mechanical deficiencies. I went to great lengths to show precisely why what you showed means nothing at all. I'm educating the wrong guy, but only because you are unable to learn.

As far as a race goes, probably not. Let me know what event you're talking about and maybe I can make it but my schedule is quite lacking in spare time. I was gonna do it if you were coming all the way to Milan, not because I think I can win but because I wanted to see if you're really so sissy that racing a bone stock SHO is your idea of a challenge. You've sufficiently proven my suspicion, so no need to go out of my way for it.
 

stripSHO

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If your fuel is low enough that a slosh will affect it then I would let darwinism take over. But I forget people are after the lowest 11 sec run even if it's only hundredths of a second... microrecords are the most dumb thing ever... but people want to be relevant and act like they did something for the platform.
Seriously. Running out of gas is going to have a universal effect, regardless of the duty cycle on your HPFP. Positive displacement pumps are sensitive to density, NOT pressure. Gasoline density changes due to pressure are microscopic and irrelevant.

Last time I left the track my dash showed like 15 miles to empty. No issues with fuel pressure in my runs. If someone is really trying to run with less than that then they need to drop the tank and install a fuel cell with a rear pickup.
 

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