PappyDan

iTrader: (4)

your not kidding their.
when i added the fuel regulator and took my stock presure from 45
and set it at 60 my svo green tops pumped out a **** load of more fuel.
when wheatly got done tuning the truck, duty cycle droped from the higher pressure.
so i know i have some room to grow.

Bill Reid

iTrader: (14)

... seems to make sense. I am at 46psi by 5500RPM. 46psi - roughly 10psi of boost (net 36 psi) and I am sure if I pushed it any further things would get nasty quick. However, boost reference the 42's from a base idle pressure of, say, 54-56psi, then I can see bit more power without having to resort to Meth........................yet...

Bill

Wilde Racing

iTrader: (26)

RPM plays a big factor in this, I've pushed my 44 pound Racetronix injectors along ways, of course they had A LOT of meth to help out. I have THREE meth nozzles two 15 gph and one 10 gph. But this set-up has alowed me to push my boost up to 14 psi (195 kpa), and with my shift points set at 5,500 rpm has alowed me to keep my duty cycle at 99-100% lol
IMO it really comes down to this, How much is your engine going to see full boost? What is your elevation? and what RPM are you going to shift at? You want a big enough injector to do the job, but not so big that the engine has a poor idle......

03sierraslt

iTrader: (22)

Go with something bigger then 42's, I am seeing as high as 108%IDC on mine shifting at 5600rpm. (7lb boost) Going to be ordering some 60lb injectors this week.

TurboBerserker

iTrader: (1)

Turbos have a much higher BSFC than an NA or N20 truck. A turbo will generally be in the 60-65 BSFC range, where an NA in the 45-55 range. That means more injector at the same power levels. Just for completeness, an SC engine fits in the middle -- around 50-60 BSFC.

TurboBerserker

iTrader: (1)

If you are still running the stock fuel pump, you won't have enough fuel pump to safely run 12psi on that motor. If you've upgraded to a 255lph pump, then you can get away with the 42 lbers if you run straight meth wide open and do a dyno tune for it. That's a bandaid for your fuel system, however, and the best fix is to go with a set of 60s and use the meth for intercooling and a little extra.

I've personally done the wide open meth trick on an LQ9, STS GT67 in an ECSB at 12 psi, but still had the stock pump and ran out of fuel (not catastrophically, but couldn't maintain the fuel pressure in boost, so turned it down). It was in the Florida heat and humidity, however, and was at sea level so results may very with climate.

With 42s, stock pump and lots of meth, 10psi is pretty much the safe limit of "on the edge" operation.

Sambo53

iTrader: (3)

Excellent thread I plan on pulleying down to the 3.00 pulley on my radix gunning for 8psi or so. Seems I should be OK in the injector department for the time being. An upgraid wouldn't hurt though. I am also planning on getting meth before long and going for 10psi for just the track, and keep 8psi for the street. This thread has answered alot of my questions.

05crew

iTrader: (6)

im the one ssturbo is talking about, i just go a sts t67 with meth, and i need to get some injectors. was looking for 42lb but i was told that i need more than 42s, so im asking do i get a 255 fule pump with 42s, or will the stock one be ok with 60lbs work. how much is a 255 fule pump? im hoping to get some were arould 500 to the wheels, is that reachable? thank for the help and all the info

TurboBerserker

iTrader: (1)

For 12 psi you need the pump and the 60s for best reliability.