XBS

iTrader: (29)

Hello,

I currently have a 4.0 stroker with APS Extreme TT CJM fuel system and twin pump (one of the first one's don't know if there have been revisions) and HKS 1000cc injectors with Vpro EMS.

Going to retune car for E85, what do you guys think will be my top power with these injectors.

I also have direct port water injection but don't think I will be needing it.

Last tune made 702rwhp dynojet on 100 oct.

Thanks for the input!

-George

rcdash

iTrader: (18)

Depends on how much headroom you have in your fuel pump and if you want to try raising base pressure. Assuming you have a twin pump 485/285 you will be injector limited and I am not sure how close to that limit you are already because you have to add 20% more E85 to get the same power. I am maxed out on injector at 850 whp on 1300 cc injectors.

EDIT: So I didn't really answer your question, so let me say I think you will actually lose a bit of power if you stick to 1000cc injectors and keep the duty cycle safe. You are correct that water injection will be useless with E85.

XBS

iTrader: (29)

Raj,

Thank you for your reply. I was figuring that I would end up in the mid 650rwhp (was hoping for 700) with my current setup. I thought my CJM twin pump was (2) 255lph walbros but not sure what they originally shipped with back in the day.

Hopefully I can still reach 700 without needing to upgrade injectors

-George

Juztin

iTrader: (9)

IIRC on my previous engine build before it dumped it's HG's, we managed to barely eek out 701 on E85 w/ 9:1. But I'd just go with the biggest you could get away with for your preferred acceptability. My 1700's are hella hard to cold start on E85. But so were the 1300's although they did seem slightly easier.

1300's we maxed DC out on ~23 psi @ 11:1 putting out 901 (E85). 1700's we ran out of pump (255/450) @ 25 psi & 1000 (E85).

I'd imagine you could go higher than those with Q16 or something with the lesser fuel volume.

bealljk

iTrader: (13)

I thought this number was closer to 30%

so if you need 20% to 30% more E85 for the same power, just back your 1000cc injectors down for gasoline, meaning:

1000cc E85 injectors will act like 700cc - 800cc gasoline injectors ... what does a 700-800cc gasoline injector put out? ~600 - 700whp +/-??

so you'd essentially be upgrading your pumps/retuning for no gain. If you want bigger outputs you gotta get new injectors. my $.02

XBS

iTrader: (29)

The gain would be the added safety of E85 not worrying about head lift. Also since you can run more timing that will make more power.

I think my injectors are rated 1000cc at 3bar fuel pressure, I have to look up what it would be at 4bar, this should definitely guarantee 700rwhp.

Thanks for your input everyone!

-George

phunk2

if its older, it would be a twin 255. The 450s didnt come out until well after the twin pumps were selling.

A twin 255 may or may not make it to 700whp on E85. It will depend on how much boost it takes, how aggressive the timing is, etc. But that is in the same range as the limit of twin 255 with E85. There is only one way to find out from here.

XBS

iTrader: (29)

Charles great to have your input it’s been a long time! I had one of the first pumps and thought it was a 255 thanks for confirming!

How you been? Hope everything has been going well for you.

-George