To get Injectors or not to...
01-23-2008, 10:53 AM
#1
To get Injectors or not to... I dont know if I want to fork out the money for some SVO 30lb. Injectors or not but I think I may need them. The car has @330rwhp and my tuner says the reason I break up in the high rpm's on my graph is because my stock injectors are maxed out. According to calculators they are at or just above 100% duty cycle and I'd like to be at 80%. Any how think it would be worth the money to upgrade? maybe the gains wouldnt be worth it?
My a/f ratio is 12.8
BTW: The car is getting a 150 shot wet eventually but considering Im going wet I assume the 30's will be good and I will be running a Walbro fuel pump at that time as well.
My a/f ratio is 12.8
BTW: The car is getting a 150 shot wet eventually but considering Im going wet I assume the 30's will be good and I will be running a Walbro fuel pump at that time as well.
01-23-2008, 11:08 AM
#2
With the mods on your sig, the stock 24lbs.injectors should be sufficient.
I upgraded to the SVO 30 lbs. when i did heads/cam.
I upgraded to the Walbro 255 lph intank fuel pump when I added the 150 shot.
If more power mods in the future, it's best to be a step ahead. Hope this helped you.
I upgraded to the SVO 30 lbs. when i did heads/cam.
I upgraded to the Walbro 255 lph intank fuel pump when I added the 150 shot.
If more power mods in the future, it's best to be a step ahead. Hope this helped you.
01-23-2008, 11:20 AM
#4
If the injectors are old, worn out, or clogged, the could be maxing out. Just because in theory they should be ok at that power level doesn't mean you should ignore them if that is the issue. On my previous car I had clogged injectors that read 93% duty cycle on a nearly stock car.
Is your tuner just guessing that is the issue or are you doing a datalog? It is very easy to check the duty cycle being used with that.
Is your tuner just guessing that is the issue or are you doing a datalog? It is very easy to check the duty cycle being used with that.
01-23-2008, 11:23 AM
#5
Your high rpm issue could possibly be valve float due to the stock valve springs with the 1.6 rockers. It may just need a second check on valve adjustments. Or it could just be the wire harness connecting to opti(corroded), or an opti going bad.
I had a similar issue last year, but at a much higher rpm, 6400. Turns out to be the opti.
I had a similar issue last year, but at a much higher rpm, 6400. Turns out to be the opti.
01-23-2008, 03:09 PM
#7
They are not stock valvesprings and I know that isnt the issue I run this thing up to 6500 no problem. The car runs like a **** and doesn't break up at all when driving or when its at the track just appears that way on the dyno graph. I have all new plugs/wires/optispark too. It could be related to my 02 sensor issue with a the heater being bad according to what my scanner says. And he did not datalog it, he is a fuel specialist and he said that the break up in the graph were the result of my injectors being maxxed so I took his word for it but figure upgrading injectors won't hurt its just the cost of them.
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01-23-2008, 03:32 PM
#8
When my 355 LT1 was putting down just a bit more power than yours, I had to pop the 30# SVO's on and retune.
If you are going with a wet kit, def. upgrade your fuel pump. If dry kit, upgrade both pump and injectors.
01-23-2008, 04:21 PM
#9
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Yea, in theory the stocks should feed 365hp, but I would assume that'd be at almost full duty cycle. Not something I'd want to be doing. There's really no harm (other than getting TOO big of ones) in upgrading injectors. I don't really see the harm in 30#, and it'll be nice to have once you spray.
01-23-2008, 05:24 PM
#12
I've got 42s on a stock cube LT1 with cam and mild heads, 1.6 rockers. I make 320/320 over a decent powerband. I don't NEED all that injector, and it took a tiny bit more tuning to get the idle perfect, but I like the idea that I can't possibly run out of injector at my power level. Duty cycle is 50-60% wide open.
Go for injectors, but consider just stepping up to the ones you'll need when mods are done; unless you go something insane like 60s you'll be able to tune 'em just fine. Plus... you can often find deals on 42s at a lower price than 30s.
Go for injectors, but consider just stepping up to the ones you'll need when mods are done; unless you go something insane like 60s you'll be able to tune 'em just fine. Plus... you can often find deals on 42s at a lower price than 30s.
