Fuel Supply Insufficient or Fuel Injector too small???

[Lady L]

Hello everyone,

I would like to get some opinion here. Getting the vehicle ready for winter storage and did one last final WOT run. Ambient temperature was about 40F and car tune was last adjusted (MAF) when temperature was still around mid 50's. Looking at the log, EQ Ratio went up to 0.82 against Commanded of 0.77. STFT tried to compensate but I think it wasn't able to drop the value. Injector Duty Cycle was up to 115 and have seen this number before even when ambient temperature was still warmer, 70's. I expected this to happen due to colder temperature but my question is, Is my Injector too small or my fuel source (pump and BAP) pressure not enough???

Vehicle info:

2013 Boss 302
Whipple Supercharger Gen4 2.9L
Stock Throttle Body
Injector stock from 2014 GT500 52# (MU52)
NGK 6510 spark plugs
exhaust manifolds with cat delete


Lean Up Top.PNG


21-10-23 08-26-32.hpl

[murfie]

I would say injectors are maxed, keep the RPM limit low.

Trusting your MAF 86 lb/min = 5160 lb/hr

high octane E10:
5160lb/ hr / 10.85 WOT stoich = 475 lb/hr - 8 injectors at 55PSI, 65lb/hr can handle this if injection window isn't too small, lower RPMs 91% DC.

475lb/hr = 290 L/h a stock pump with a BAP can do that maintaining 55PSI, coyote pumps at 17.5V can flow 400+ L/h at 60PSI. Provided they are given good amperage and not too restrictive of fuel lines.

Compare that to E85

E85:
5160lb/ hr / 7.47 WOT stoich= 691 lb/hr - 8 injectors at 55PSI, 65lb/hr can not do even close to this.

691lb/hr = 424 L/h stock pump and BAP will not maintain 55 PSI at that flow rate. pressure would be dropping like crazy.

[Lady L]

I would say injectors are maxed, keep the RPM limit low.

Trusting your MAF 86 lb/min = 5160 lb/hr

high octane E10:
5160lb/ hr / 10.85 WOT stoich = 475 lb/hr - 8 injectors at 55PSI, 65lb/hr can handle this if injection window isn't too small, lower RPMs 91% DC.

475lb/hr = 290 L/h a stock pump with a BAP can do that maintaining 55PSI, coyote pumps at 17.5V can flow 400+ L/h at 60PSI. Provided they are given good amperage and not too restrictive of fuel lines.

Compare that to E85

E85:
5160lb/ hr / 7.47 WOT stoich= 691 lb/hr - 8 injectors at 55PSI, 65lb/hr can not do even close to this.

691lb/hr = 424 L/h stock pump and BAP will not maintain 55 PSI at that flow rate. pressure would be dropping like crazy.

Thanks for the reply Murfie. You and your numbers always come in very useful. You don't disappoint!!!

Anyways ... granting all my injector data is correct and all of them are working as they should, I should have a total of 520 lb/hr of available fuel at 100% DC. That should give me about 10% headroom for the fuel required (475 lb/hr) at that instant isn't it.? So my DC during that time should have only been 90% to match the requirement, correct? There must be something wrong with the numbers of Injector DC Hp tuners is giving or my injectors are not flowing the right amount of fuel as per given data.

Secondly, I checked my Alternator Desired Output Setting [ECM 44202] and only have 14.87V max setting. Using your math, this voltage will only give me 340 L/h coming from the pump. Would this be enough to satisfy the demand of 290 L/H?

I agree with you to lower down the rpm to cut down the DC but would upgrading a much higher flow Injector be better so that I won't have to sacrifice my top speed? And what injector would you suggest that would be easier to dial in for Idle/Part Throttle tuning?

Alternator output.PNG

[Lady L]

Any suggestions to what injector make I should upgrade my MU52 to get satisfy my fuel needs. Max HP power target is 700RWHP @ 7500rpm. Currently car is making 630RWHP/540lb.ft but goes lean starting at 7200rpm as what is shown in the log. As what has Murfie pointed out and I agree with him, I need to go to a bigger injector because my Injector DC is already maxed out. I don't want to sacrifice my top speed using the MU52. A good idle/part throttle behaving Injector is preferred. Thanks

[veeefour]

LU80 - they are cheap and work fine

[Lady L]

LU80 - they are cheap and work fine

veeefur .... I checked this LU80 and it is has a longer length compared to MU52. I don't know how it's going to affect the seating of the fuel rails on Whipple Supercharger Gen4 2.9L.

Anybody has got experience on changing a mid length injector to a longer length on their whipple supercharger Gen4?

[veeefour]

Not a lot of middle length injectors out there - either short or long. Might try DW95 and take out the adapters.
Long injectors should work just fine in your setup

[Lady L]

Not a lot of middle length injectors out there - either short or long. Might try DW95 and take out the adapters.
Long injectors should work just fine in your setup

I have to check the spacings of the whipple fuel rail to see if using a longer length injector will not interfere anything when rail is raised up.

[Lady L]

I contacted Injector Dynamics and ask for their direct replacement for my needs. This is what they came up with:

MUSTANG GT 2011+ | ID1050-XDS | INJECTOR DYNAMICS | 1050.60.14.14B.8

https://www.t1racedevelopment.com/pr...14-14b-8-copy/

Anybody here have used it on their S197 coyote and what your experience was? Any installation issues with whippple fuel rail?