ckpitt55

iTrader: (4)

Starting to sort the rest of the details out on my build, and my attention is now turning towards the fueling aspect of things. I'm looking for recommendations on injector size as well as fuel rail selection for use with a FAST 102 intake. This is a built n/a LS1 that will probably be in the neighborhood of 500hp when it's all said and done.

According to my numbers using the RC calc:
-500rwhp =~ 550bhp assuming a 10% loss
-Assumed 58 psi fuel pressure (corvette regulator / filter)
-Fuel demand: 37.x lb/hr

I was going to go with 42 lb'ers. Is this an appropriate size? They would act like 43.57 lb/hr injectors running them at the higher pressure (most are tested around 42 psi). Wasn't sure if having this much headroom was appropriate or not.

Also what does everyone like to run for fuel rails on a FAST 102? I need something with -AN connections. I've seen the fast rails and nasty performance rails (which I like at the moment). Any recommendations are appreciated.

Thanks,

Chuck

bristol16

iTrader: (36)

I have a fast 102 intake and 92 throttle body with 42# injectors and fast fuel rails with LS1 crossover kit. I haven't run the motor yet but it should be plenty of fuel and the setup looks damn good. With my setup I'm shooting for 500hp at the wheels plus a 150 shot on top of that.

ckpitt55

iTrader: (4)

which injectors are you using? do you have to use fast injectors with their rails?

bristol16

iTrader: (36)

I'm not sure who makes them but they are LS1 height injectors, basically stock replacement injectors. The rails I have will accept pretty much any injector, I think they are fairly universal. You just need to check the height for your application...LS1, LS2, and I believe LS7 style injectors are all different heights and use two different connectors (EV1 and EV6). You can buy adapters to go from one connector type to the other, so it's easiest to pick injectors based on the height you need.

Exidous

iTrader: (11)

I use a LS2 stock rail(middle height injector), LS3 inj(short injectors), FIC 1/2" top spacer and some EV1-EV6 adapters from ebay. The LS3 injectors can be had for $120 on ebay. Only issue is they are about 1" shorter than the LS1 injectors(tallest inj. about 1" taller than LS3). When I was running LS1 style injectors I had a 1/2" spacer for the rail. Moving to the LS3 injectors I removed the rail spacer and adder 1/2" injector spacer. Worked out great.

Best way to think about the injectors is the height of course.

Using a close but random height as I cannot remmeber off the top of my head.

LS1 3" tall
LS2 2.5" tall
LS3/7 2" tall

With the fast 102, an LS2 rail and LS2 injectors require no spacers.

LS3 rail and LS3/7 inj need no spacers. (possible issue with rail not clearing height of intake).

LS1 rail with LS1 injectors needs no spacers.

LS1 rail and LS3/7 injectors needs 1" spacer on the injector.

I suggest the 42lb LS3 injectors. The inj data is easily available for the LS1 ECU on the HPTuners forum. If you are using LS3/7 injectors then get LS3/7 rails(OEM or aftermarket). Fast has a calculator thingy on their site that will tell you which rail to get. I only bought the injector spacers because I already had a rail and the spacers were a lot cheaper than a new rail.

Edit: The fat LS1 style injectors like the racetronics will not fit the FAST intake without removing some of the material around the injector. It doesn't affect the seal or anything. It's just some extra work and you have to grind your new $1000 intake. Any injector can be used with any rail. It may just require different o-rings and/or spacers.

James@ShorTuning

The LS1 and LS3 rails don't bolt up to the Fast102 due to bolt hole alignment and height... I'm sure you may be able to modify them in order to work but I've not personally done that. I've always used stock LS2 rails or aftermarket rails. FIC sells the small 1/2 inch adapters to go ontop of the LS3/7 injectors to fit right in the factory LS2 rails. That is the setup I generally push just due to the LS3/7 injectors supporting ~550-600rwhp on NA setups and they have good data and nice spray patterns.

Exidous

iTrader: (11)

Fair enough. I guess I was just lucky I was already using an LS2 rail. :-)

ckpitt55

iTrader: (4)

Thanks for the replies guys

I think I'm going to try and avoid the need for spacers / injector harness adapters. I'm going to go with ls1-height rails and ls1 style injectors.

Are there any LS1 style 42# injectors that definitely have sufficient clearance on a 102 manifold? as mentioned above the racetronix injectors are too big in diameter and interfere with it. I've seen the bosch's but I think they look like hell in green lol

sick_ss camaro

I am attempting to assemble the fast 102 intake. I also purchased the fast fuel rails for the LS 1
I have 42 pound injectors with the larger bottom Oring. My issue is the brackets to mount the rails to the intake don't seem to line up and I assume there are spacers according to what I have read but I can't find the information I need to obtain the correct spacers and or brackets could someone please lead me in the right direction I would appreciate it thank you