i havent seen too many people with all of their mods using bigger injectors. why? i had a 98 gst with a t28 and when i upgraded to the 660cc injectors-what a difference. just wondering if upgrading to the 660cc and increasing boost along with an SAFCII would give good results. i see alot of other people just flashing and increasing boost without other mods. and then i see other mods like i/e, cam gears, cams, etc. and using stock injectors. when do the stock injectors run out of duty cycle?? wouldnt it be best if you had the bigger injectors and not running them at almost 90% duty cycle all the time?? anyones thoughts, experiences??

 

i run 660cc

 

The Evo has stock 550cc, not 450 like the 2Gs, so they are larger to start with. Stock Evos are sickly rich on boost. Most flashes lean them out to a respectible 11:1 AFR range...that will save some duty cycle. Even without a flash, it's so rich, there is definitely headroom to work with mods before running out of injector becomes an issue.

As for what actual duty cycles are, that would depend on a lot of things, including actual mods, boost level and weather. Many people are probably close to 90% if not over with many bolt-ons, cams and higher boost on stock injectors. I personally installed a Walbro before and upgraded the injectors about a week after I put the cams in so I didn't have to worry about it. They currently peak about 78% DC (lotsa bolt-ons, cams, ~22psi, 11.1:1 AFR), so the stock 550s would presumably be about 98%. Of course, if running stock boost/leaner AFR, that # would be lower.

Yes, adding bigger injectors early and leaning out with a SAFC does the same magic (reduce chances of cut, increase timing) that it does on DSMs, but there is plenty of room to do that even on the stock injectors until you start getting some mods on the Evo...

 

This is what a guy at the shop recommened i do. Get 660's and tune then with afc to high boost around 26 but on here every1s sayin that its not possible or its dangerous. I keep going back and forth

 

Consider a different source of advice.

 

I would agree

 

...I'd agree also.

 

I dont agree (with that shop's advice), but I do have Denso 660's

 

Since there are persons making 350whp (DJ) without exceeding the capacity of the stock injectors, it's simply another of many ways to spend money and not get more power.

Larger injectors more or less fall into the same category as a larger IC. You won't really benefit from it until/unless you go to a larger turbo.

 

now I disagree with mainly the intercooler example...

 

Consider that popular aftermarket ICs have been shown to make an improvement of only ~3-4whp (1%) at the 360whp (DJ) level, and these findings appear to be consistent:
https://www.evolutionm.net/forums/sh...d.php?t=107992

Some may feel that 1% is worth $700, but I don't. With some of these cars running well into the 11s with the stock IC, it's not much of a debate.

 

SAFC + injector upgrade + pump gas = too much timing advance and leaving a ton of power on the table. You can get away with it using race fuel, but it certainly isn't a good idea. This is why a ton of DSMs with big turbo and injector upgrades are still slow as butt crack.

 

so would it be a bad idea or a safe idea?? my mods are going to be-SAFCII, 660cc, fuel pump, intake, turbo back exhaust, greddy BOV, HKS boost control. i would rather have too much headroom for the injector DC, than run into 98% DC and overheat the injectors cause your pushing them all the time.

i understand the dynamics of the race fuel, but who is going to drive the car all the time with race fuel?? i drive the car daily, and with the CA. gas getting more and more expensive to buy, it kills the pocket book having to fill up the tank every three days. not to mention about the tune having to be made for the race gas and not the crappy 91 oct.

i guess what im trying to achieve is an honest 300 horsepower to kill most street cars and to easily pull away from the annoying hybrid swap(b16 or b18 or whatever) civic or ITR on the free way to leave me alone. i was happy with the big i/c , 660cc injectors, safc, turbo back exhaust, intercooler pipes, intake, and an hks t28 turbo with a ported o2 housing on my 98gst. was able to pass cars on a two lane road easy and to pull away from tailgaters on the freeway with ease. i was running 18psi with a hks evc ez boost controller and i was very happy.

how many other people have this sort of set up and are happy with it?? i know stand alone is the way to go for BIG hp, but what about CA smog and such?? what about the ones who dont have a laptop to constantly tune or pay for the dyno time all the time or dont have access to one?? just thoughts and opinions are welcome...

 

Why are you contemplating doing things that will only leave power on the table and cost you time and headaches in fiddling around? If money is an issue and you really want 300whp (DJ), forget the SAFC, injectors, intake, BOV, and HKS Boost control. You don't need any of this.

Get your exhaust, get an Xede+Xflash, get a set of HKS 264 cams if you have the funds, and have it dyno tuned one time and be done with it. You'll get your 300whp (at least), and you won't be wasting time fiddling with gadgets or spending money on things you don't need.

 

ok .... dont listen to this dumb guy..