55LB Injectors for Whipple Gen V Stage II

[engineermike]

I just went through this and wanted to add some facts to clear this up a bit and save someone else the trouble. This is regarding Gen3 Coyote GenV, 4-bolt Whipple blower:

The old 38's are the exact same length as the stock Gen3 Coyote and the 2020-22 GT500 injectors (sold as Ford Performance M-9593-M55GT). These are considered "Long body" injectors and NOT what Whipple supplies.

The spacers are just washer-shaped shims, not like tube-shaped extensions with o-rings. I'd love to know more about why these washers are needed rather than just machining the injector holes shallower.

The Whipple housing has 2 sets of fuel rail holes. The "Long" injectors mentioned above use the upper holes.

Whipple supplies the 2013/4 GT500 injectors with the later and current Gen3 kits, just as Lethal Stephen posted earlier, and Ford Performance calls these MU52s. The flow rate at 39 psi is nearly identical to the 55's in the 2020 GT500/M55GT. However, the injector data is fairly different at different pressure and flows, different minimum PW, different high/low breakpoint, etc., so they aren't interchangeable without tuning. Also, the 52 height is shorter than the 55's, as it is classified as a "Medium length" injector. These use the lower fuel rail screw holes in the Whipple lower manifold.

And finally a word of caution...sometimes tuners hack the injector data if they can't get the MAF or speed-density models correct. If you swap in different injectors and use correct data, it may not run right if the old injector data was bandaided.

Sponsored

 

[engineermike]

One more thing….the 2020 gt500/ford performance m55gt injectors are scaled out to 150 psi fuel pressure in the gt500 stock tune. The gt os will only accept 128 psi in the axis so the scaling factor needs to be interpolated before it’s transplanted to make it work right.

 

[bankyf]

I just went through this and wanted to add some facts to clear this up a bit and save someone else the trouble. This is regarding Gen3 Coyote GenV, 4-bolt Whipple blower:

The old 38's are the exact same length as the stock Gen3 Coyote and the 2020-22 GT500 injectors (sold as Ford Performance M-9593-M55GT). These are considered "Long body" injectors and NOT what Whipple supplies.

The spacers are just washer-shaped shims, not like tube-shaped extensions with o-rings. I'd love to know more about why these washers are needed rather than just machining the injector holes shallower.

The Whipple housing has 2 sets of fuel rail holes. The "Long" injectors mentioned above use the upper holes.

Whipple supplies the 2013/4 GT500 injectors with the later and current Gen3 kits, just as Lethal Stephen posted earlier, and Ford Performance calls these MU52s. The flow rate at 39 psi is nearly identical to the 55's in the 2020 GT500/M55GT. However, the injector data is fairly different at different pressure and flows, different minimum PW, different high/low breakpoint, etc., so they aren't interchangeable without tuning. Also, the 52 height is shorter than the 55's, as it is classified as a "Medium length" injector. These use the lower fuel rail screw holes in the Whipple lower manifold.

And finally a word of caution...sometimes tuners hack the injector data if they can't get the MAF or speed-density models correct. If you swap in different injectors and use correct data, it may not run right if the old injector data was bandaided.

Does Whipple hack the injector data? I can't make any sense of the injector data in my Whipple cal while comparing to the Ford supplied MU52 data.

 

[engineermike]

Does Whipple hack the injector data? I can't make any sense of the injector data in my Whipple cal while comparing to the Ford supplied MU52 data.

I have been told that it is but haven't confirmed. However, you have to be careful comparing injector data. It could look very different but be identical. You have to multiply the "flow rate high" by the "flow rate high multiplier vs pressure" to get the flow at any given pressure. The Gen2 calculates rail pressure and the Gen3 measures it, while both calculate manifold pressure from the SD model. The result is used to determine the injector dP, which is then used to look up the actual injector flow rate at that dP.

 

[engineermike]

Couple updates:

The 2020 GT500 injectors are improved over the older 13/14 injectors. The flow rate is very similar but the dynamics are better. Not a big deal but just FYI.

More importantly, I installed the 2020 models and my car started making a pretty noticeable ticking noise. I isolated the noise to the port injectors by running 100% GDI at idle. I wound up removing the Whipple washer/spacers and the noise is totally gone. I believe the injectors were in interference with the rail and lower manifold, making the injector noise resonate in the blower housing. I don't know when the washer/spacers are appropriate to use, but it's not here. What ticks me off is they were pretty expensive for what you get and Whipple told me in writing that I needed them.

Thirdly, PCMTec allows you to scale the injector slope data to 150 psi in the Gen3. By doing this, you can more easily transplant the GT500 data.

 

[Rolls]

Does Whipple hack the injector data? I can't make any sense of the injector data in my Whipple cal while comparing to the Ford supplied MU52 data.

I know that I've never seen a flow bench match the numbers that Ford come up with, even with a variety of test fluids in other vehicles (eg the Australian Ford 4.0L Barra motor).

What I don't understand is why Ford still use a low/high slope model and not a simple 1d lookup table so you can accurately model the injectors around the breakpoint.

I guess you can fudge this with the MAF curve, but that changes your speed density/load and hence changes transmission shift pressures and anything that uses load/torque as an input.

 

[S14Wolf]

I just went through this and wanted to add some facts to clear this up a bit and save someone else the trouble. This is regarding Gen3 Coyote GenV, 4-bolt Whipple blower:

The old 38's are the exact same length as the stock Gen3 Coyote and the 2020-22 GT500 injectors (sold as Ford Performance M-9593-M55GT). These are considered "Long body" injectors and NOT what Whipple supplies.

The spacers are just washer-shaped shims, not like tube-shaped extensions with o-rings. I'd love to know more about why these washers are needed rather than just machining the injector holes shallower.

The Whipple housing has 2 sets of fuel rail holes. The "Long" injectors mentioned above use the upper holes.

Whipple supplies the 2013/4 GT500 injectors with the later and current Gen3 kits, just as Lethal Stephen posted earlier, and Ford Performance calls these MU52s. The flow rate at 39 psi is nearly identical to the 55's in the 2020 GT500/M55GT. However, the injector data is fairly different at different pressure and flows, different minimum PW, different high/low breakpoint, etc., so they aren't interchangeable without tuning. Also, the 52 height is shorter than the 55's, as it is classified as a "Medium length" injector. These use the lower fuel rail screw holes in the Whipple lower manifold.

And finally a word of caution...sometimes tuners hack the injector data if they can't get the MAF or speed-density models correct. If you swap in different injectors and use correct data, it may not run right if the old injector data was bandaided.

Sorry to bump this thread from the dead but I wanted to clarify because I think I'm running out of injector.

So if I'm reading this correctly. If we have the old Whipple 38lb kit injectors on a old Gen3 coyote gen5 blower, we need to replace them with part # M-9593-M55GT GT500 2020 injectors or else we will need shims and different rails.

 

[engineermike]

First, what makes you think you’re running out of fuel?

 

[S14Wolf]

First, what makes you think you’re running out of fuel?

I've been told these kits don't have a lot of headroom and I'm looking at going below the 3.875" pulley to something smaller.

 

[engineermike]

I've been told these kits don't have a lot of headroom and I'm looking at going below the 3.875" pulley to something smaller.

The whipple 38's will go way further than many would have you believe, but you'd need to get familiar with data logging. I was actually on E85 before I found the actual limits of the 38's. There are things you can do in the tuning around GDI system optimization and Lift pump control that greatly extend their range.

Sponsored