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Discussion Starter · #1 ·
Hi Folks,

Here is a datalog of Hammer's car today at Epping, NH. The purpose of this was to see how Rich's fuel system was holding up to the 600+rwhp that his twin-screwed Cobra was making.

Although the car appears to be running rich, one can see from this chart that he is running out of fuel system and that there is ZERO safety margin. As he hits 5900rpm, his fuel pump is running full out at 100% duty-cycle. As his power continues to increase beyond this point (indicated by the continual increase in the MAF rate), the fuel pressure starts to drop because the PCM can not increase the pump output any further.

Hammer's car has a BAP but he's not using it. The BAP is an excellent method of extending the range of the stock fuel delivery system (i.e. pump). If there is a larger twin in-tank pump setup available then that would be another excellent way of getting more fuel but contrary to what a lot of people are spouting, the BAP is not a POS and it is a very valuable tool in the hands of a good tuner.

So, the bottom line is this: if Rich's car sees more boost due to cooler weather or the fuel pump starts to fatigue, he's going to end up running lean due to the fact that the PCM can not increase the duty cycle any further to maintain its desired pressure.

Comments?

Best,

MJ
 

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What about the 255 lph pumps a vendor here was talking about a couple weeks ago. One of my concerns would the PCM be able to control them at idle or would they flow to much at the PCMs lowest duty cycle?
 

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MJ,

I should probably ask Rich this ?? But how much boost were running ? Still 3" upper and stock lower ? For bout 17-19lbs ??

Also was this in 4th gear ?

Just in comparison. I datalogged my KB with 20-21lbs boost couple weeks ago. MY MAF was pegging 482.22 G/S @ 5010 rpm to 6200 but my FP-rail was 57-60psi to 6200 with BAP set @ 1/2 way. This was with the New KB Chip.

I need to DataLog the FPDM next time I am out . Very interesting results ! Have you found any larger returnless pumps to fit our setup yet ? :)

Jon L
 

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Discussion Starter · #4 ·
Dustoff said:
MJ,

I should probably ask Rich this ?? But how much boost were running ? Still 3" upper and stock lower ? For bout 17-19lbs ??

Also was this in 4th gear ?

Just in comparison. I datalogged my KB with 20-21lbs boost couple weeks ago. MY MAF was pegging 482.22 G/S @ 5010 rpm to 6200 but my FP-rail was 57-60psi to 6200 with BAP set @ 1/2 way. This was with the New KB Chip.

I need to DataLog the FPDM next time I am out . Very interesting results ! Have you found any larger returnless pumps to fit our setup yet ? :)

Jon L
Don't quote me but I think he's running 17psi. The pulls were in 3rd gear as we did them on the street. :shocked

Hammer's car was running a JDM modified MAF and it still didn't *peg* at the 600rwhp level. You can't go by the absolute numbers because the MAF curve was scaled down. To see that it still had range left, take a look at how the MAF rate continues to increase as his RPM goes up......it never flatlined.

You've probably heard people say "whatever can be done with the BAP can also be done in a chip.....the BAP is not necessary." right? This is B/S. Yes Delta_P can be totally controlled in the chip right up until the PCM runs out of FPDM duty-cycle. At that point the only recourses are: 1) bigger pumps or 2) BAP.

MJ
 

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Discussion Starter · #5 ·
toofast4u said:
What about the 255 lph pumps a vendor here was talking about a couple weeks ago. One of my concerns would the PCM be able to control them at idle or would they flow to much at the PCMs lowest duty cycle?
Excellent question. Well, if I turn the BAP up to 25% on my car and have it on all the time (no hobbs switch), the car won't start because the PCM can not lower the FPDM duty cycle below 20%. If you put larger pumps in the car and effectively do the same thing, you will run into a similar problem with low-load driveability UNLESS your chip is tuned properly to make the PCM aware of the new pumps flow curve.

I can't comment on any specific pump as I have no experience with it. I do have extensive experience with the '03 Cobra setup however.

MJ
 

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This is B/S. Yes Delta_P can be totally controlled in the chip right up until the PCM runs out of FPDM duty-cycle. At that point the only recourses are: 1) bigger pumps or 2) BAP.

MJ
I agree 100% I don't see any PSI increase using the boost a pump but I know it is running correctly with the new KB chip. I can also hear the pumps whinning louder with the BAP maxed.

JL
 

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mjchip said:
Hammer's car was running a JDM modified MAF and it still didn't *peg* at the 600rwhp level. You can't go by the absolute numbers because the MAF curve was scaled down. To see that it still had range left, take a look at how the MAF rate continues to increase as his RPM goes up......it never flatlined.

MJ
Would it be hitting a higher MAF rate at a lower RPM if it was in 4th gear ?

Do you know is the JDM modded MAF a factory tweek version ? What would be modded the electronics ?

Sorry for so many ??s

Just interested !

Jon L
 

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Discussion Starter · #8 ·
Dustoff said:
Would it be hitting a higher MAF rate at a lower RPM if it was in 4th gear ?

Do you know is the JDM modded MAF a factory tweek version ? What would be modded the electronics ?

Sorry for so many ??s

Just interested !

Jon L
In 4th there may be more load at the same RPM.

Yes, the JDM unit is a modified '03 Cobra MAF. The sampling tube is modified.

MJ
 

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toofast4u said:
What about the 255 lph pumps a vendor here was talking about a couple weeks ago. One of my concerns would the PCM be able to control them at idle or would they flow to much at the PCMs lowest duty cycle?
I heard that the Focus pumps would work in place of the stock pumps and be good for more power. Not sure how much though.
 

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You are right Eric...but not ANY Focus pumps. I spent some time with John Sealock, owner of Woodbridge Dynotech, this weekend and we talked about this issue for some time. He has one heck of a setup in his shop and he was able to show me why he advises all the 03 owners to install the 255 pumps. Before and after data he has aquired was amazing.....and pretty convincing to me. Total control of fuel pressure from idle to WOT. He is the guy somebody should be talking to. I am sure that everyone making the kind of horsepower Hammer is would include this upgrade on their list.
 

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Well PSP sells the 255 pumps for the Lightning and people have never had problems with them.

Wonder if has a solution for the Cobra's?
 

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predator said:
You are right Eric...but not ANY Focus pumps. I spent some time with John Sealock, owner of Woodbridge Dynotech, this weekend and we talked about this issue for some time. He has one heck of a setup in his shop and he was able to show me why he advises all the 03 owners to install the 255 pumps. Before and after data he has aquired was amazing.....and pretty convincing to me. Total control of fuel pressure from idle to WOT. He is the guy somebody should be talking to. I am sure that everyone making the kind of horsepower Hammer is would include this upgrade on their list.
Yes, Hammer will definately need to upgrade. I have also heard great things about Woodbridge Dynotech and that kick ass data acquisition system they have. Randy Haywood is doing the tuning there now as well ;-)
 

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Mark,
Great info. What datalogging software were you using, Autotap on a laptop?

I think I an going to finally pull the trigger on it. I might need some hints on how to use it...
 

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Discussion Starter · #14 ·
JT said:
Mark,
Great info. What datalogging software were you using, Autotap on a laptop?

I think I an going to finally pull the trigger on it. I might need some hints on how to use it...
Hey JT,

Autotap on a laptop is a pretty good datalogger. The only problem is the slow data rate of the earlier version that I have. Supposedly the new 2.X version is faster.

Give me a call anytime and I'll do my best to point you in the right direction. Sorry I was such a zombie on the phone today; I was punching keys on the laptop at the track when Hammer handed me the phone and said here talk to JT. I guess I suck at multitasking. :(

MJ
 

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I noticed in the original post someone, alot of talk was made about the pulse rate of the pump, did you guys log the Injector duty cycle as well??

The 255 pumps you guys are referring too. Are these walbro 255 pumps? If they are I can pick them up for about 90/piece. I think they are also the same pump that goes in the earlier stangs as well, since the 255 is an upgrade pump for earlier style stangs also.

Im also curious too see if your 02 sensor values started dropping off past 5900 as well. A pretty conservative tune will put you in the .092 area with a boosted obd2 car. IF the car was starting to show signs of getting lean your 02 sensor logs will indicate those as well. I think its bank1&2 sensor 1?? The front 02's.

Im wondering if the injector is somewhere near maxing out as well?? Wouldnt mind seeing what the duty cycle is like as well, should be represented in a "m/s" format in ATAP.

I had a buddy who was using twin 255's and 50lb'rs in his 03 and kept going threw fuel rail pressure sensors, seems as it was too much for the sensor to handle. Maybe it was just his car. 255's have been know to run massive amounts of base pressure, and overflow stock regulators, at least they did on Talon's and eclipses. With the returnless systems though, its a whole other game.

He switched back to the stock fuel setup and everything seemed to of worked fine, hasnt went threw one since.

Later
 

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I'm trying to point you in the right direction for all these questions guys.......John and company at Woodbridge Dynotech have this part figured out. Give him a call. It would be useless for me to try to convince you otherwise. Like Eric says, he has a one-of-a-kind data aquisition system. Megabytes of data on different cars with pretty pictures/graphs for people like me that address everything you guys are talking about. All the before and after stuff you are looking for. He found exactly what mjchip found with the pumps on Hammer's car in other 03 Cobras.....and in other high horsepower Mustangs. John will tell you that if you want more boost.....replace the pumps. They are not an expensive item and can be got from the dealer. It seems we have a "pump friendly" tank that makes the job easier than you might think. Good piece of mind for the long haul.
 

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The 255 lph pumps being discussed in this thread, where are they from?

Are they meant for a returnless system, or are they the old return style? I understood that the returnless pumps are unique to be driven by a PWM signal? Is this true?

I also heard that the retrun style pumps would work, at least for some time, used in a PWM returnless sytem.

It would be nice to have a definitive answer on whether the pumps are actually different, or if either pump could be used with the same "life" in either control system.
 

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If there is a larger twin in-tank pump setup available then that would be another excellent way of getting more fuel but contrary to what a lot of people are spouting, the BAP is not a POS and it is a very valuable tool in the hands of a good tuner.
Joe, maybe you need to take a course in reading comprehension. I never said "a good tuner knows how to use a BAP."
HMMMMMMMMMMMMMMM
 

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Wow, this thread degraded fast and from where I sit I have no idea why. All MJ was trying to say is that the fuel pumps are only capable of receiveing the max voltage that a car can supply based on its charging system and at this level there is zero room for error. He is saying that by adding a BAP it will up the voltage to the fuel pumps regardless of what the cars electrical system is putting out because the BAP is in essence a step-up xformer. All MJ is trying to say (please correct me if im wrong here) is that the use of a BAP may not be needed under ideal circumstances and not needed to make the car function BUT it is a good idea to have in place incase the cars electrical system has a power drop, the BAP will step up the voltage and give us a bit of overhead we wouldnt otherwise have.

I swear a lot of tuners sure are touchy and dont read these threads very well....LOL either that or I misread the thread myself :)
 
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