Injector Sizing For E85

[rbs30]

Hi all.

Ok so i have decided to save the rb30 build for a later date, mainly because I need to get my motor out, built and back in as quick as possible due to it being my daily and having no spare. Anyway, I have a forged bottom end on its way as well as arp head stud kit plus vrs to rebuild head and gaskets to stock.

I also have a haltech plus a hg 43g3 on the way and walbro fp. My question is, I have some 800cc injectors here from a previous build. Do you think these will be enough? I know 300kw is prob starting to push them but will I get away with it for a while? I havent played with e85 before so i dont even know if 300rwkw is even realistic with that setup. Opinions? Thanks in advance.

Edited October 15, 2012 by rbs30

[s213b]

From what I've gathered, you need to pretty much double your injectors for an e85 build. If your turbo is in that range and you've got a decent tuner 300rwkw on e85 should be a breeze.

I'm currently pricing up an e85 build on my rb25, aiming for 400-450awhp and have been told I'll need a big fcker of a pump and 1000cc injectors.

My guess is should be ok with upped fuel pressure

Hope that helps

Edited October 15, 2012 by s213b

[The Dan]

Hi all.

Ok so i have decided to save the rb30 build for a later date, mainly because I need to get my motor out, built and back in as quick as possible due to it being my daily and having no spare. Anyway, I have a forged bottom end on its way as well as arp head stud kit plus vrs to rebuild head and gaskets to stock.

I also have a haltech plus a hg 43g3 on the way and walbro fp. My question is, I have some 800cc injectors here from a previous build. Do you think these will be enough? I know 300kw is prob starting to push them but will I get away with it for a while? I havent played with e85 before so i dont even know if 300rwkw is even realistic with that setup. Opinions? Thanks in advance.

800cc injectors = 435hp at the wheels

We used to devide injector size by 12 but have found it to be more like 11

[GTSBoy]

Yuh, 800cc injectors are about 100HP short of the target.

[rbs30]

435rwhp = more than 300rwkw. So I should be right. But I may be better to just go 98 Ron for the moment and up injector size and retune in 6 or so months when I have cash. Don't want to be too close to the limit.

435rwhp at what duty cycle?

[GTSBoy]

Sorry, you're right. I divided by 0.75 twice instead of just once.

The duty cycle will be quite close to 100% at 435.....depending on pressure of course.

[wedge_r34gtr]

Just grab some 2000's and have the capacity for later on

Edited October 15, 2012 by wedge_r34gtr

[Mick_o]

You might JUST squeeze it in with them I'm running a tomei pump and power enterprise 850cc injectors and I'm at 336rwkw and injectors are bout 80% duty cycle

[The Dan]

435rwhp = more than 300rwkw. So I should be right. But I may be better to just go 98 Ron for the moment and up injector size and retune in 6 or so months when I have cash. Don't want to be too close to the limit.

435rwhp at what duty cycle?

435rwhp is a safe maximum assuming your pump is up to the task.

For 300rwkw (400rwhp) you need 4.5L/min fuel flow to be safe

[AngryRB]

my 1000's are at 70% with 430hp

[Bratva]

If i have 750cc injectors and i go for a tune with a nismo fuel pump @ 14v how much rwkw can i expect ? I am wanting hopefully around 320rwkw on E85.

Or should i grab some 1000cc injectors to be safe ?

And if i want to drive to the tuner, can i just plug in that nistune cable and then set the injector size on the pre-existing tune or is there more to it ?

Thanks

[Mick_o]

If i have 750cc injectors and i go for a tune with a nismo fuel pump @ 14v how much rwkw can i expect ? I am wanting hopefully around 320rwkw on E85.

Or should i grab some 1000cc injectors to be safe ?

And if i want to drive to the tuner, can i just plug in that nistune cable and then set the injector size on the pre-existing tune or is there more to it ?

Thanks

Need to know more than what injectors u have mate lol! The nismo pump will be fine I believe they are good for up to 400kw........Stand to be corrected if I'm wrong lol

[rbs30]

Ok cool. Sounds like it will be close enough. I'm running a walbro 90000267 e85 pump. If that runs out ill just use my old one as a lift pump and run 2 of the e85 pumps off a surge tank.

I think the way to go is to just run e85 and tune it to a safe injector duty cycle and be happy with it until I've got money for bigger squirters.

Cheers for the assistance.

[GTSBoy]

Your 750s are going to be wide open.

[GTR_JOEY]

might as well just buy 2000's, they are a better injector the then sard 800s anyway

[DVS JEZ]

The 400 lph walbro will be fine, im running one on my GTR with e85 402kw. Im running id2000's however, Though 300 kw is doable with 800's.

[Bratva]

Need to know more than what injectors u have mate lol! The nismo pump will be fine I believe they are good for up to 400kw........Stand to be corrected if I'm wrong lol

Its already made 304rwkw on 98 fuel so the other mods are fine, im just worried the injectors are too small for e85. Is it bad if they are at like 90% duty cycle ? Its not a track car so i wont WOT all the time.

[NYTSKY]

If i have 750cc injectors and i go for a tune with a nismo fuel pump @ 14v how much rwkw can i expect ? I am wanting hopefully around 320rwkw on E85.

Or should i grab some 1000cc injectors to be safe ?

And if i want to drive to the tuner, can i just plug in that nistune cable and then set the injector size on the pre-existing tune or is there more to it ?

Thanks

I have made 360rwkw with Nismo 740cc with some head room. You will be fine at 320rwkw.

[Bratva]

I have made 360rwkw with Nismo 740cc with some head room. You will be fine at 320rwkw.

Is that with E85 ?

[NYTSKY]

Yes.