draggin97s10

iTrader: (2)

i dont believe that to be true, but i dont have the facts to back it up. So.... i cant argue..

bowtienut

iTrader: (1)

This subject has been hashed and rehashed so many times for so many years.
I know all the theory; I've run all the numbers; looked at tons of data on my own car and others' cars. Seen injector duty cycles (as reported on DM) exceed 100% routinely even on roadrace cars and never seen an injector failure with the SVO's on those vehicles.
I'm an engineer, so I don't dismiss theory lightly. But when the theory doesn't support real life, it's flawed.
One theory that I believe as to why smaller injectors work better is not the spray pattern per se, but the transient (on/off) time as a percentage of total flowing time; the atomized fuel available for combustion is more consistent.

You can listen to the people who figure things out for themselves and go fast or you can listen to those who just repeat some "well-articulated" arguments they've read.

05HD

I know you and Daren are both fast, that is why I wanted to hear why you guys thought it was working. Know anyone who has tried some of the new stuff like injector dynamics?

blackjack325

iTrader: (1)

OEM injectors are 24lb right? On 97's at least is what I've read. That good enough for a .040 over block with le2 head and cam package? Would it depend on the cam size?

SS RRR

iTrader: (2)

I was at 370rwhp running 12.0 @ 115 with stock injectors and duty cycle was approx 85% IIRC. '94 and up are indeed 24lb'ers.

TravisMcGill2000

iTrader: (2)

Thanks for all the info guys. I will try the svo's and see how they do..

Rob94hawk

iTrader: (1)

I have 42's so you should do quite well with them.

GIZMO

iTrader: (8)

I had 42 lb injectors on my LS7 (389 ci). The ¨experts¨ said that I didn´t have near enough injector. After I made a couple of dyno pulls they went quiet (588 rwhp)!

I have 24 lb injectors in Gump. I feel that the reason the smaller injectors work better is that you get better atomization at WOT. My 24´s are not maxed. I have tried different brand 30´s and have always lost performance. The only way to know for sure what your combination needs is to run a wide band and data log the runs.

Rob94hawk

iTrader: (1)

Interesting. I use 42's just incase I had the insane thought of using nitrous. Didn't think about the atomization. Would be nice to run a wide band and see if it could be fine tuned as well. Damn car is running so strong now I can't imagine I could gain anything from an injector change. But then again I'm not a tuning expert.

97pontta

iTrader: (10)

Very interesting thread. I'm also in the market to purchase a set of injectors for my 355 AI 200cc H/C build and have been recommended anywhere from 30lb to 42lb injectors but I haven’t been able to decide what to get. I've had the stock fuel system from fuel pump to injectors up until this point so I know very little about what to upgrade to as the stock stuff was doing just fine on the old engine.

Also, I've been under the assumption just from reading through many different threads over the years that anything above 90% injector duty cycle is a bad thing and can cause injector failure or lean condition. But from what Gizmo and Bowtienut have stated that doesn't seem to be true. I’m thinking the 30lb injectors will be fine for me as well.

draggin97s10

iTrader: (2)

i was thinking about sticking my stockers back in, turning the pressure up to around 50, re-tuning it and seeing if it'd work. Reason being i have a 36 lber sticking. So im gonna try it.

05HD

I thought this was an interesting video. I think what you guys are doing with these little injectors running WFO is making a huge cloud of fuel in the intake. Better atomization than they best new injectors.

http://www.youtube.com/watch?v=PGlav...eature=related

lt1slowz28

are you trying to say the stock multecs atomized better?



might wanna watch the video again.

05HD

*sigh* It is guys like you that make me wonder why I even bother posting in here.

No matter what injector, it makes a big cloud when you run it wide open as opposed to just a cone at lower duty cycles.

Uwilllosetomy93lt1

Personally, the 30lbr's should work fine, even with a wet kit.....provided the (more importantly)pump has been upgraded for the 200 shot. 36lbr's would also work OK, whereas the tune shouldnt be too bad to work out. The 42 lbr's would be a bit much to scale back, despite what others have heard or might have done, but can still get tuned into your set-up.....just easier to tune with good results on dyno with smaller injectors! Just my experience...

Rob94hawk

iTrader: (1)

Any dyno or track results from switching to smaller injectors?

lt1slowz28

Well, gizmo and bowtienut have both voiced their views... gizmo is pretty damn smart about his set up... but other than running the injector at it's max all of the time I feel more comfortable myself with my street/strip car on a bigger injector running the solenoid on a less intensive duty cycle.

GIZMO

iTrader: (8)

How often is your street/strip car actually at WOT? One thing that you might want to consider is that too large injectors do not perform as well in low load situations. When we switched to 19 lb injectors in our stock internals build we gained a bunch in sixty foot. FYI, my SVO 24 lbs are not maxed out (50 psi). I am not saying that the OP needs to switch to 24 lbs. I am just trying to share what has worked for me. Buying a set of matched injectors is worth the extra money.

Rob94hawk

iTrader: (1)

Makes sense. After I'm done driving around town I smell the stench of raw fuel. Almost like I'm still running rich. Poor atomization at low rpms maybe?

So if I were to swap out smaller injectors would a fuel pressure regulater need to go with it?

lt1slowz28

Good thoughts gizmo... I wish injectors were as cheap as carb jets to play with and find the right combo... I may just try the injectors out of my mustang and see how they fair