Bosch 105s on e85. Can they make 1000+?

[Lstruck03]

Well, I thought i had everything lined up for my new fuel system, but the car made a lot more power than expected, and now with the build, and switch to e85, I am afraid I will not have enough fuel.

Old setup with stock longblock, single 78mm on 21 psi with 91/torco mix made 876 (dynojet). This is was with 80s and 3x ford gt pumps, returnless.

New setup will be 9.7:1, ported 03 heads, degreed 98 cams, same turbo on ~25psi. I have bosch 105s and 3x "upgraded ford gt pumps". I will be using an aeromotive pro series regulator, 10 feed, 8 return. I am shooting for no more than 1100rwhp (dynojet)

Somethng tells me I need to look for 160lb + injectors, and maybe more pump.


Has anyone made big power on 105s or id1000s?

 

[JeremyH]

I agree more pump and injectors to be safe. I have bosch 1000cc injectors with e85 and started to max them around 20lbs of boost and around 850rwhp+ I would guess (we had to let out as the injectors were maxing and we were going lean when full boost came in, even though fuel pressure was solid) So I backed it down to 16lbs of boost and made 760rwhp. I do run 40psi base pressure. At 60psi base pressure they may scratch 1000rwhp on corn. But 60psi base pressure plus 25lbs of boost and your in the 75-80psi range which those ford GT pumps will be struggling at. I run a walbro 465 and aem 340 staggered pump Fore setup.

 

[blckRadda]

Pressure drop across injectors plays a very important role here, if you plan on keeping it low, 105s ain't gonna cut it for the power you are aiming for on e85, if you raise it they will probably get the job down but be close to the edge, keep in mind though the higher the pressure drop the less the pumps can flow. Keep pressure drop low get higher flowing injectors (Id1300 maybe) The upgrade Ford GT pumps I don't think is going to cut it for you. So ID1300 two 450 lph pumps could get it done

 

[04cobrawhine]

I made 900 with 105s. Tuner said there's plenty of room left. I run a Weldon 2345 pump though so there's no shortage there. Pressure is 44psi with 15" or vacuum. Increases on a 1:1 ratio with boost, so at 20#, fuel prssure is around 65psi.

 

[JeremyH]

I made 900 with 105s. Tuner said there's plenty of room left. I run a Weldon 2345 pump though so there's no shortage there. Pressure is 44psi with 15" or vacuum. Increases on a 1:1 ratio with boost, so at 20#, fuel prssure is around 65psi.

I have my regulator set to 40psi with key on car off, it is boost/vac referenced as well. I have 15-16" vac and see around 29-30psi at idle. So your static base pressure is around 54-55psi then, the injectors should handle close to 1000hp on e85 with that base pressure.

 

[04cobrawhine]

That's correct. I did my math wrong lol. I have a kinda unique setup (PWM return style system) so the volume vs pressures may be a little different. None the less, 105s can get the op 1000 with the right pressure.

 

[JeremyH]

Indeed if your system can handle the higher pressure it will push the injectors farther. Its just not always ideal depending on your pump setup since pump flow starts dropping a lot north of 60-70psi when you throw boost in the mix. Most fuel pumps only flow their advertised rating at 39-42psi. So the higher your static or base pressure is and the more boost you run the lower the flow and power potential for the pumps. For your setup that Weldon pump (250gph/947lph at 40psi) putts out a lot of flow at higher pressure still (around 200gph) even at 80psi (758lph). But the average in tank pump sees a drop of 35-40% flow at 80psi. A gss 255lph pump for example that flows around 260lph at 39psi, only flows around 150lph at 80psi.

Looking at that weldon pumps numbers and the pressure your seeing at max boost, it is indeed capable of 1000rwhp on e85 with 105 injectors. But not much more maybe 1050-1100. Its defiantly not a linear curve up top, flow starts dropping a lot faster as you push pressure higher and higher. There comes a point where you have to lower boost, step up injector size and bring base pressure back down so the pump can flow the fuel it needs to support the power.


For reference a twin walbro dcss 465 setup is around 850lph of flow and is rated to 1000rwhp on corn with a 40psi base pressure and 30lbs of boost or less.


On my setup I was able to coax more power out of my setup and fuel system by keeping base pressure low and lowering boost some while adding timing with e85. Lowering boost allow the injectors to go further while not hurting flow of the pumps. I'm a fan of keeping base pressure at what the pumps and injectors are rated for. Each setup will be different and there's more than one way to skin a cat.

 

[Lstruck03]

What I am looking at is a triplet of pumps that flow 346lph at 40psi, 310lph at 60psi and 264lph at 80 psi. all together at 80psi is still over 755lph.

I think however I will move on to a 160lb/hr injector. I'd like to stay around 40 psi base to make the pumps happy. I plan on no more than 25 psi, so that should keep fuel pressure in the mid 60's and pump flow around 850-900lph.

 

[JeremyH]

Sounds like a good plan for the setup.