GTP Injectors LT1 Install

[95Hawk326]

Hey guys, I've tried searching for a good write up on installing the GTP injectors on the LT1. My setup is block bored .020 over. 227/235 110 lsa, le2 heads and ported intake. I'm running the Racetronix 255 pump and I got a set of 8 GTP injectors, flow matched and all that stuff, for a steal. All I've been able to gather is that the oe clips won't work, but has anyone actually gone this route? Everyone says they've read about it, or heard about it, but I have yet to see a formidable write up. Any help?

Sent from my Pixel using Tapatalk

[Sahara54]

I installed the pencil style on another LT and just ran without clips. The rails held the injectors in place just fine with no leaks.

[MoeHorsePower]

I installed the pencil style on another LT and just ran without clips. The rails held the injectors in place just fine with no leaks.


^^^ Yup

[The Batman]

I have heard of guys running gtp injectors but I'm very educated on the topic. What ones do people buy? What is the flow rate? Are they just supposed to be a good/affordable upgrade for those that need it?

[fullforce]

I have heard of guys running gtp injectors but I'm very educated on the topic. What ones do people buy? What is the flow rate? Are they just supposed to be a good/affordable upgrade for those that need it?
From what I gather they are just a cheap way to get higher flowing injectors.
I think GTP 36lb/hr Vs lt1 24lb/hr

[95Hawk326]

I installed the pencil style on another LT and just ran without clips. The rails held the injectors in place just fine with no leaks.Thanks

Sent from my Pixel using Tapatalk

[95Hawk326]

^^^ YupThanks

Sent from my Pixel using Tapatalk

[95Hawk326]

I have heard of guys running gtp injectors but I'm very educated on the topic. What ones do people buy? What is the flow rate? Are they just supposed to be a good/affordable upgrade for those that need it?I just found a set of oe used injectors from a GTP. I don't think it matters between the series 2 or 3 motors. 36lb/hr is the flow rate, and yes, they are an affordable option for bigger injectors. There are several others that work too, and they are fairly easy to find. It depends on your setup. Lloyd recommended 36lb injectors for the LE2 setup I'm running. I just couldn't find anything on the install process, specifically any mods required. Sounds pretty straightforward though.

Sent from my Pixel using Tapatalk

[Injuneer]

Are the GTP injectors flow rated at 43.5 PSI, like LT1 injectors?

[95Hawk326]

Are the GTP injectors flow rated at 43.5 PSI, like LT1 injectors?Not from what I've read. GTPs are rated at 50-52psi so the injectors will flow ~33lb on the stock LT1 fuel pressure based on an online calculator.

Sent from my Pixel using Tapatalk

[Injuneer]

That's what I thought. The later non-S/C 3.8's were rated at 3.5 bar = 50.75 PSI. Wasn't sure if S/C was the same. Based on 3.5 bar vs. 3.0 bar (43.5 PSI) the conversion would be 33.3 #/HR.

[superspirit]

I DO NOT recommend running without clips! When I bought my LT1 the injectors were installed without clips, 1500 miles later I started smelling fuel I stopped and looked and the #8 injector had come out of the rail far enough to spray fuel all over the engine compartment and firewall. It was a very scary situation as I was taking my little girl to school when this happened. there are ways to modify the injectors so they can be retained. I HIGHLY recommend going this route!

[95Hawk326]

I DO NOT recommend running without clips! When I bought my LT1 the injectors were installed without clips, 1500 miles later I started smelling fuel I stopped and looked and the #8 injector had come out of the rail far enough to spray fuel all over the engine compartment and firewall. It was a very scary situation as I was taking my little girl to school when this happened. there are ways to modify the injectors so they can be retained. I HIGHLY recommend going this route!

Any pics of the injector mods?

Sent from my Pixel using Tapatalk

[superspirit]

No I dont have any pics, but I got a set of modified injectors from fuel injection connection and they worked great.
If you are a patient person you could mark the new injectors for the clip and take a hacksaw blade and carefully make a retainer clip groove.
take a look here https://fuelinjectorconnection.com/collections/gm-car-rebuilt-injectors/products/30lb-modified-bosch-3-fuel-injector-set

[SSlowBoat]

Any pics of the injector mods?

Sent from my Pixel using Tapatalkyou just take a hack saw blade and make the 1 groove that doesn't go all the way around go all the way around. takes 10 mins. that's it.

also there are 2 different part numbers for gtp injectors, one flows 33lb and other 35.99lb so I set injector constant to 34.5lb

Sent from my SM-N950U using Tapatalk

[Catmaigne]

There's the 811 (all plastic) and 737 injectors (plastic with metal bottom). They always seem to run best around the high 33lb/low 34 lb range but I wouldn't worry about the constant that much. Tweak it until the BLMs are centered on 128.

I've had good luck with with doubling up on o-rings to keep the injectors from pushing out of the rails. There's a groove directly above where the lower o-ring sits that you can add another onto. It will prevent the injector from moving too deep into the intake boss because the groove ID is larger.

Sent from my VS995 using Tapatalk

[SSlowBoat]

There's the 811 (all plastic) and 737 injectors (plastic with metal bottom). They always seem to run best around the high 33lb/low 34 lb range but I wouldn't worry about the constant that much. Tweak it until the BLMs are centered on 128.

I've had good luck with with doubling up on o-rings to keep the injectors from pushing out of the rails. There's a groove directly above where the lower o-ring sits that you can add another onto. It will prevent the injector from moving too deep into the intake boss because the groove ID is larger.

Sent from my VS995 using Tapatalkthe o ring will dry out and break causing it to slide down. I've personally had it happen. I strongly suggest against this

Sent from my SM-N950U using Tapatalk

[BALLSS]

you could add a wider OD (with same ID as the 811 upper slot) O ring in the upper groove that may help. These pencil injectors are narrower that the stock ones

[SSlowBoat]

you could add a wider OD (with same ID as the 811 upper slot) O ring in the upper groove that may help. These pencil injectors are narrower that the stock ones43.5psig behind a uncontained o ring is spelling disaster. scariest moment of my life was #7 spraying on my hot idling motor and header by doing that.

op, I'll get you a pic Sunday when I go to my car for its monthly startup of how to do it right

Sent from my SM-N950U using Tapatalk

[Catmaigne]

Never had a viton Felpro o-ring dry out and break before, they're tough as hell and hard enough just to get on. If you really want to be anal you could pop a metal E clip above it in the lower groove.

Sent from my VS995 using Tapatalk

[The Batman]

you just take a hack saw blade and make the 1 groove that doesn't go all the way around go all the way around. takes 10 mins. that's it.

also there are 2 different part numbers for gtp injectors, one flows 33lb and other 35.99lb so I set injector constant to 34.5lb

Sent from my SM-N950U using Tapatalk
What is the model for the higher rate ones? I may order a set soon and want to make sure I get the right ones (higher flow rate)

[SSlowBoat]

What is the model for the higher rate ones? I may order a set soon and want to make sure I get the right ones (higher flow rate)if you're gonna order new injectors just order 36lb Bosch 3's from fic

Sent from my SM-N950U using Tapatalk