What size injectors? X-Post
12-01-2003, 01:39 PM
#1
What size injectors? X-Post
I am going to order from Racetronix sometime in the next week or so. I just wonder what size? Car will have MAF, T04E, TiAl, etc, etc, etc. I am planning on running 18 psi with HP goal of about 375. My question is what size injector to get? They have about 5 Seimens to choose from. I would guess the 57 lb/hr (they refer to them as 55 lb/hr in the description) would be fine with some sort of aftermarket FPR? Low "Z" or High "Z"?? Do you really need ballast resistors? Seems like I read something different from everyone.
Thanks.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
Thanks.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
12-01-2003, 01:57 PM
#2
Addict
Rennlist Member
Rennlist Member
I got the 55lb/hr lowZ, haven't run them yet though to know what kind of duty cycle I'll be at. You do need ballast resistors with them, in the last good injector/Racetronix thread in this section was a link to Newark Online to get them cheap.
Sam
Sam
12-01-2003, 02:32 PM
#4
So you are using the stock regulator with 72 lb/hr injectors? Cool. Tony, are you running anything special as far as DME chip? I know you are running an aftermarket KLR chip. Will I need new ones burned or will my HR chips that came with the MAF suffice? I assume I will be able to adjust the ARC-2 do deal with the new turbo.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
12-01-2003, 03:41 PM
#5
Rennlist Junkie Forever
Matt
I'm using, currently, a standard set of Autothority K27 chips with their KLR chip. Are you running a HR DME & KLR chip?
I use the Pro-M from Lindsey with their Bullet 75mm MAF.
Although the ARC2 is an excellent unit, I don't know if you will have the adjustability down low (just off idle) as you can't tweak things with the resolution of the Pro-M, with the ARC2.
I guess that you would be fine though....
TonyG
I'm using, currently, a standard set of Autothority K27 chips with their KLR chip. Are you running a HR DME & KLR chip?
I use the Pro-M from Lindsey with their Bullet 75mm MAF.
Although the ARC2 is an excellent unit, I don't know if you will have the adjustability down low (just off idle) as you can't tweak things with the resolution of the Pro-M, with the ARC2.
I guess that you would be fine though....
TonyG
12-01-2003, 03:46 PM
#6
Right now I am using nothing as the car is still not together. I have a set of HR DME/KLR chips that came with the MAF. The whole kit is from Huntley (split sec). Using those chips with the custom turbo should be okay?
Also, just to make sure I am understanding you, you are using 72 lb/hr injectors (with or without ballast resistors) and the stock FPR?
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
Also, just to make sure I am understanding you, you are using 72 lb/hr injectors (with or without ballast resistors) and the stock FPR?
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
Trending Topics
12-01-2003, 04:09 PM
#8
Three Wheelin'
Matt, 55 lb injectors should be good for about 340 rwhp at 80% duty cycle. They would likely be pushed past 90% duty cycle at 375 rwhp, but I don't think that is a realistic goal at 18 psi with your mods imho. TonyG was making about 330-340 rwhp with a similar level of mods iirc. Steve Wiggins needed to go stand-alone and 25 psi to make 390 rwhp out of a 2.5 L. Ian M. was making about 320-330 rwhp out of a T04E-50 at 18 psi.
Remember how injectors are rated, though. They will be 55 lb/hr at some pressure rating, usually (but not always) 3 bar. If you run them at 2.5 bar, they become 50 lb/hr injectors. You would then need need about 90% duty cycle for 340 rwhp, and would be better off with the next size larger injectors.
Remember how injectors are rated, though. They will be 55 lb/hr at some pressure rating, usually (but not always) 3 bar. If you run them at 2.5 bar, they become 50 lb/hr injectors. You would then need need about 90% duty cycle for 340 rwhp, and would be better off with the next size larger injectors.
12-01-2003, 04:13 PM
#9
Thanks guys. Oz - got pictures of where the resistors go or what to do with them? I am not sure I understand why they are needed.
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
12-01-2003, 04:20 PM
#10
Rennlist Junkie Forever
Matt
I use no resistors. The injectors are the Siemens and I purchased them from Lindsey.
I also use the stock FPR, as well as the larger fuel pump from Lindsey.
TonyG
I use no resistors. The injectors are the Siemens and I purchased them from Lindsey.
I also use the stock FPR, as well as the larger fuel pump from Lindsey.
TonyG
12-01-2003, 04:24 PM
#11
Nordschleife Master
Originally posted by Waterguy
Matt, 55 lb injectors should be good for about 340 rwhp at 80% duty cycle. They would likely be pushed past 90% duty cycle at 375 rwhp, but I don't think that is a realistic goal at 18 psi with your mods imho. TonyG was making about 330-340 rwhp with a similar level of mods iirc. Steve Wiggins needed to go stand-alone and 25 psi to make 390 rwhp out of a 2.5 L. Ian M. was making about 320-330 rwhp out of a T04E-50 at 18 psi.
Remember how injectors are rated, though. They will be 55 lb/hr at some pressure rating, usually (but not always) 3 bar. If you run them at 2.5 bar, they become 50 lb/hr injectors. You would then need need about 90% duty cycle for 340 rwhp, and would be better off with the next size larger injectors.
Matt, 55 lb injectors should be good for about 340 rwhp at 80% duty cycle. They would likely be pushed past 90% duty cycle at 375 rwhp, but I don't think that is a realistic goal at 18 psi with your mods imho. TonyG was making about 330-340 rwhp with a similar level of mods iirc. Steve Wiggins needed to go stand-alone and 25 psi to make 390 rwhp out of a 2.5 L. Ian M. was making about 320-330 rwhp out of a T04E-50 at 18 psi.
Remember how injectors are rated, though. They will be 55 lb/hr at some pressure rating, usually (but not always) 3 bar. If you run them at 2.5 bar, they become 50 lb/hr injectors. You would then need need about 90% duty cycle for 340 rwhp, and would be better off with the next size larger injectors.
2,5 bar is the fuel pressure at athospheric pressure. The FPR is connected to the vacuum system so at 18 psi (1,22 bar) the fuel pressure is 3,72 bar.
12-01-2003, 04:27 PM
#12
Can the stock fuel pump push enough fuel for 72-75 lb/hr injectors?
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
12-01-2003, 04:31 PM
#13
Three Wheelin'
Matt, I have the ballast resistors spliced in near the DME. They are installed so that the resistance of the injectors plus the resistors is close to the resistance of the original injectors. If the resistance is too low the current will be higher than the DME was originally designed to handle. That May result in a shorter life for the circuit that operates the injectors. How much shorter life... I really couldn't say.
12-01-2003, 04:35 PM
#14
I get it now, thanks! I think I am going to go without and see what happens. I was having this discussion about the heat shield for the starter, it is such a bitch to remove I dont care if it cuts the life in half!
Do you know about the stock fuel pump? Will it be able to go for at least a little while running injectors that large? I would love a little time to recover before spending even more!
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
Do you know about the stock fuel pump? Will it be able to go for at least a little while running injectors that large? I would love a little time to recover before spending even more!
__________________
Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
12-01-2003, 04:38 PM
#15
Three Wheelin'
Join Date: Jun 2001
Location: San Jose, CA
Posts: 1,598
Likes: 0
Received 0 Likes
on
0 Posts
Stock fuel pump is fine up to about 460HP i've heard....no actual experience. Matt, I'm using 55lb injectors at 3 bar fuel pressure on my new turbo. I think that's towards the limit of the 55's but I was concerned about going too large with the injectors.