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View Full Version : RB25 sidefeed injectors!


wowzers9930
04-04-2014, 07:38 AM
Okay with my goal of 500whp I decided to stick with the stock side feed rail. My fuel setup is Walbro 400 pump, Deatschwerks 740cc injectors, Nismo FPR...

Rawbrokerage recommends upgrading to top feed and going with 1000cc injectors for my goal. What do you guys think? Is 740 enough injector for pump gas 500whp?

OBEEWON
04-04-2014, 08:41 AM
It should be but you will be running a higher duty cycle than if you did 1,000cc. I really hate to say this but higher HP RB25's are a pain in the neck to tune. Thats why I dumped mine for a 1J.

wowzers9930
04-04-2014, 08:51 AM
I got tuning covered, Prolly going haltech platnium pro and having Mike at Innovative Tuning tune it. I just need to know if they will be at a healthy, okay duty cycle. Id like people who have used 740s and made decent power to let me know their results.

dftsilvia
04-04-2014, 06:44 PM
you will be at very close to maxing out 740s if your trying to make 500whp.
just do it right the first time and take the advice raw brokerage gave to you.

funny your having innovative do the tune. they are right in my hood

edit* at 80% duty cycle u will max out 740s.

cotbu
04-04-2014, 10:44 PM
Tuners consider all injectors maxed out at 80%, not that they are or can't go to 85-90. it's like a rule of thumb.
Anyway if your tuner suggest a size, it's probably a good idea to follow it. Not all tuners, tune the same. You could have a tuner that tunes those 1000cc injectors to 80% and still not make that 500hp goal.
That being said, using a B.S.F.C. of .65....max duty 80%, 740cc's should be enough for 500hp and leave some wiggle room. I wouldn't use DW injectors for this though, preference!
So sure even a bad tuner should be able to get 500hp from an rb25 with 740cc injectors and supporting mods on pump gas, but it would be less stressful with 1000cc injectors.

fliprayzin240sx
04-04-2014, 11:34 PM
Id ask the guy who's gonna be tuning your stuff...if anybody's opinion would matter the most at this point, it would be that guy. Personally, I think 740cc on an RB is enough to do 500, 850cc should be good to about 600-650.