Direct drop in bigger injectors?

**AMD IS THE BEST** · 7-21-05, 19:28

Anyone ever find a direct drop in larger injector for 1990+ GT's? I have recently installed megasquirt and at 15psi the duty cycle is maxed out. I would like to get larger injectors, but I would like them to drop right in. Any info would be great. Thanks, Nick

**KiNg MaRtY** · 7-21-05, 19:38

order some from RC
http://www.rceng.com/Default.htm

**mx6GT91** · 7-21-05, 19:55

Id do DSM 450's. You will need resitors for each injector, very easy to do.
Im running 390's now, bogs a little when revving but through the gears its great.

**KiNg MaRtY** · 7-21-05, 20:14

do the dsm's run the same ohms unlike the supras?

**mx6GT91** · 7-21-05, 20:18

Im not sure, they probably do. DSM's are low impedence, ours are high.

**KiNg MaRtY** · 7-21-05, 20:21

does that matter though?

**SixSick6** · 7-21-05, 20:59

Quote:

Originally Posted by AMD IS THE BEST

Anyone ever find a direct drop in larger injector for 1990+ GT's? I have recently installed megasquirt and at 15psi the duty cycle is maxed out. I would like to get larger injectors, but I would like them to drop right in. Any info would be great. Thanks, Nick

Have you actually gotten on a dyno with realtime A/F ratio? Or done it with a wideband?

**mx6GT91** · 7-21-05, 21:21

Quote:

does that matter though?

Yes. If the ohms are higher than whats called for the injector can/will overheat and die out. My grandfather gave me a big lecture about ohms, what resistors do, how to find the right resistor. I listened but there was too much math for me to remember it all.

**AMD IS THE BEST** · 7-22-05, 2:36

Quote:

Originally Posted by SixSick6

Have you actually gotten on a dyno with realtime A/F ratio? Or done it with a wideband?

The wideband is on its way in the mail. I know right now I am rich, but not horribly (narrow band). I still want larger injectors only because I know that they shouldn't be hitting 120+% duty cycle at only 15-16 psi on the T3. I plan on running 18-20 psi so bigger injectors are needed. Nick

**SixSick6** · 7-22-05, 2:42

So you've never actually gotten on a dyno with realtime A/F via wideband O2. Don't be so sure you need what you think you need. There have been multiple members who have run similar turbos (you do know that not all "T3's" are created equal right?) and have had A/F ratios in the 10's, 11's and 12's with the same boost you plan on running. Save the money that you plan on using for "10,000 cc inject0rs" for somethign silly like dyno time or better yet, brake rotors.

**AMD IS THE BEST** · 7-22-05, 10:33

The wideband is coming, no need for dyno time. Over the winter I plan on replacing the T3 with a T3/T4E .58 45 trim and I just wanted to see what injectors would drop in. Thanks, Nick

**SixSick6** · 7-22-05, 12:04

No need for dyno time? You don't plan on calculating whether or not your turbo is ill suited for the motor/transmission by how much power you make at which rpm?

**rebel2k4** · 7-22-05, 12:10

You and your ill suited arguements. A dyno tells you numbers and a/f. Big deal. Higher numbers are what we want, but it is "ill suited" for our weak drivelines. Darn.

My friend tuned his 300zx with SDS to 17 psi on a 60-1 with no indication of a/f at all. Just ears, feel, and sight.

When we finally threw it on a wideband it was 11:1 across the board, amazing what you can do when you know what detonation sounds like.

With megasquirt, you have to build a flyback board to run low impedance injectors. You can use resistors and its easier, but I hear you lose PWM control. No biggie.

FC RX7 n/a (86-91) 460cc. They require a little shaving on the pintle no big deal. The later years are high impedance (88-91 I believe) so go for those if you can find them.

1G DSM's are 450cc low impedance, and 80's supra turbos are 440cc low impedance.

**rebel2k4** · 7-22-05, 12:15

Also, what you may want to try is crushing your FPR a little in a vise. Bump that base fuel pressure up to 50 psi or so at least.

Stock is 36, you can safely go to 80 at the pintle (total FP-boost)

So theoretically, if you're wanting to push 20 psi, you can get that fuel pressure up to 100 psi at the rail in boost.

Go grab a guage at home depot and crush the base fuel pressure to like 65 psi. That will give you a bit more flow, provided you have a pump that can handle this.

You can also do this with 460's or whatever when you get them too, that should give you all the fuel you'll ever need.

I have 550's in my v6, it equates to having 800cc injectors in a 4 cylinder. Its too much. On 10 psi (280 whp or so) I am at 34% duty cycle. lol

**anarchyx34** · 7-23-05, 12:13

FC RX7 injectors will drop in and are 550cc's. They're also high impedance so you wont need a resistor pack or flyback module.

7-21-05, 19:28	#1 (permalink)
AMD IS THE BEST DOHC Join Date: May 2003 Location: Schenectady, NY, USA Age: 23 iTrader: (0)	Direct drop in bigger injectors? Anyone ever find a direct drop in larger injector for 1990+ GT's? I have recently installed megasquirt and at 15psi the duty cycle is maxed out. I would like to get larger injectors, but I would like them to drop right in. Any info would be great. Thanks, Nick
	90' PGT, FE-DOHC, GT35R, MSnS - 13.2 @ 114 - RIP 2001 Audi S4 - Stage 3 99.5 Audi A4 2006 Yamaha YZF-R6

7-21-05, 19:38	#2 (permalink)
KiNg MaRtY Join Date: Apr 2003 Location: Anaheim, Orange County, CA, US Age: 24 iTrader: (0)	order some from RC http://www.rceng.com/Default.htm Last edited by KiNg MaRtY : 7-21-05 at 19:41.
	05 STI 92 Galant VR-4 90 Eclipse GSX HKS' Former Promo Car 89 MX6 GT 4WS SOLD 89 PGT R.I.P 93 PGT5 /93 PGT5-SOLD/89 PGT-R.I.P. /96 PGT5 R.I.P.

7-21-05, 19:55	#3 (permalink)
mx6GT91 Join Date: Jul 2002 Location: Orlando, FL Age: 22 iTrader: (0)	Id do DSM 450's. You will need resitors for each injector, very easy to do. Im running 390's now, bogs a little when revving but through the gears its great.
	Anyone want a NICE 1G? :-/

7-21-05, 20:14	#4 (permalink)
KiNg MaRtY Join Date: Apr 2003 Location: Anaheim, Orange County, CA, US Age: 24 iTrader: (0)	do the dsm's run the same ohms unlike the supras?
	05 STI 92 Galant VR-4 90 Eclipse GSX HKS' Former Promo Car 89 MX6 GT 4WS SOLD 89 PGT R.I.P 93 PGT5 /93 PGT5-SOLD/89 PGT-R.I.P. /96 PGT5 R.I.P.

7-21-05, 20:18	#5 (permalink)
mx6GT91 Join Date: Jul 2002 Location: Orlando, FL Age: 22 iTrader: (0)	Im not sure, they probably do. DSM's are low impedence, ours are high.
	Anyone want a NICE 1G? :-/

7-21-05, 20:21	#6 (permalink)
KiNg MaRtY Join Date: Apr 2003 Location: Anaheim, Orange County, CA, US Age: 24 iTrader: (0)	does that matter though?
	05 STI 92 Galant VR-4 90 Eclipse GSX HKS' Former Promo Car 89 MX6 GT 4WS SOLD 89 PGT R.I.P 93 PGT5 /93 PGT5-SOLD/89 PGT-R.I.P. /96 PGT5 R.I.P.

7-22-05, 10:33	#11 (permalink)
AMD IS THE BEST DOHC Join Date: May 2003 Location: Schenectady, NY, USA Age: 23 iTrader: (0)	The wideband is coming, no need for dyno time. Over the winter I plan on replacing the T3 with a T3/T4E .58 45 trim and I just wanted to see what injectors would drop in. Thanks, Nick
	90' PGT, FE-DOHC, GT35R, MSnS - 13.2 @ 114 - RIP 2001 Audi S4 - Stage 3 99.5 Audi A4 2006 Yamaha YZF-R6

7-22-05, 12:10	#13 (permalink)
rebel2k4 Join Date: Mar 2002 Location: 5900 ft above you aka the highest elevation state in the USA, CO, USA Age: 23 iTrader: (1)	You and your ill suited arguements. A dyno tells you numbers and a/f. Big deal. Higher numbers are what we want, but it is "ill suited" for our weak drivelines. Darn. My friend tuned his 300zx with SDS to 17 psi on a 60-1 with no indication of a/f at all. Just ears, feel, and sight. When we finally threw it on a wideband it was 11:1 across the board, amazing what you can do when you know what detonation sounds like. With megasquirt, you have to build a flyback board to run low impedance injectors. You can use resistors and its easier, but I hear you lose PWM control. No biggie. FC RX7 n/a (86-91) 460cc. They require a little shaving on the pintle no big deal. The later years are high impedance (88-91 I believe) so go for those if you can find them. 1G DSM's are 450cc low impedance, and 80's supra turbos are 440cc low impedance.
	94 MX3: 400+ whp E85 alcoholic. 13.0 @ 114 93 Nissan Pathfinder: Remote mounted T3 turbo 01 Yamaha YZ250 04 Suzuki GSX-R600 12.55 @ 115.4 98 Ford Ranger 3.0L

7-22-05, 12:15	#14 (permalink)
rebel2k4 Join Date: Mar 2002 Location: 5900 ft above you aka the highest elevation state in the USA, CO, USA Age: 23 iTrader: (1)	Also, what you may want to try is crushing your FPR a little in a vise. Bump that base fuel pressure up to 50 psi or so at least. Stock is 36, you can safely go to 80 at the pintle (total FP-boost) So theoretically, if you're wanting to push 20 psi, you can get that fuel pressure up to 100 psi at the rail in boost. Go grab a guage at home depot and crush the base fuel pressure to like 65 psi. That will give you a bit more flow, provided you have a pump that can handle this. You can also do this with 460's or whatever when you get them too, that should give you all the fuel you'll ever need. I have 550's in my v6, it equates to having 800cc injectors in a 4 cylinder. Its too much. On 10 psi (280 whp or so) I am at 34% duty cycle. lol Last edited by rebel2k4 : 7-22-05 at 12:18.
	94 MX3: 400+ whp E85 alcoholic. 13.0 @ 114 93 Nissan Pathfinder: Remote mounted T3 turbo 01 Yamaha YZ250 04 Suzuki GSX-R600 12.55 @ 115.4 98 Ford Ranger 3.0L

7-23-05, 12:13	#15 (permalink)
anarchyx34 Experiment 626 Join Date: Sep 2000 Location: Staten Island, NY Age: 31 iTrader: (0)	FC RX7 injectors will drop in and are 550cc's. They're also high impedance so you wont need a resistor pack or flyback module.
	Anarchyx '98 VW Jetta K2- Daily driver. '94 Miata C-package- Tein S-tech, Tokico Illumina, FCM bump stops & 15" OZ Superleggera, MSPNP