FS: Better Injectors for 94-95 LT1s

If you read enough of my posts you'll know I'm no fan of the stock injectors, but for awhile I really didn't have anything to offer as a replacement. Several of you had PM'd me asking what to do. Well, I finally have something. This post is long but I'm not out to make a quick buck; this is a permanent solution to the LT1 injector problem that will pay for itself in better gas mileage, better drivability, and supports up to 500hp should you upgrade your motor.

I've been tuning B-bodies for about a decade and knew firsthand the stock injectors are now garbage. They were designed in the early 1980s (nearly 40 years ago!) with wet windings and were never intended for ethanol. The last time I tried, it took me two sets to finally get a single set that flowed evenly, working with WitchHunter Performance.  BTW they charge $23 per injector with a $12 return shipping fee, so that'd be almost $400 nowadays. The Rochester Multec injectors GM used on LT1s are on WitchHunter's naughty list of problem injectors.

Why not just put a different set of 24lb injectors in that physically fit? Because their internals are different; Thus, the way they respond to voltage fluctuations is different. So is the response time, which really becomes significant at startup, idle and part throttle with really short pulsewidths. What about all the common LT1 swap injectors like the SVO red tops, green tops, ACCEL, etc? Try finding the voltage offsets and short pulse adders for those injectors. I never saw a single mail-order tune change anything but the flow rate. As a result, drivability was always poor. You can read more about that here: Injector Characterization. And those bright colored ones on Ebay for $50 a set?  Those are most likely Chinese counterfeits. Good luck getting any consistency from them.

After much research and hunting, a fellow tuner and I sourced a 30-years newer injector design from Siemens. We were able to obtain the full characterization data, then calculate the needed LT1 values. What we ended up with is injectors that flow 36lb/hr (stock is 24), are ethanol proof, have a significantly improved spray pattern, and far better drivability. One guy's car sounded mean but drove so poorly that he only took it to car shows. After these injectors (and some tuning), he drove it to work every day. Every set I've installed, I've seen up to 10% reduction in fuel consumption. These will support up to 500hp should you choose to upgrade your motor. It was great, but our source of low mileage takeouts dried up and I could never locate more.

Recently I was able to get my hands on a few remaining low mileage sets in excellent condition (NOT from the junkyard, in case you're wondering). I've also added all the physical and electrical adapters necessary to make them drop-in to your LT1. Depressurize your fuel system, unbolt the rails, lift them up, swap injectors, bolt the rail back down. Done.

You WILL need the PCM reprogrammed. You can buy a cable and download/upload yourself, or send the PCM to me for updating. If you don't already have a cable, you can buy a nice one from www.aldlcable.com, or build a USB interface yourself for under $10 if you're handy. As a side benefit of having a cable, you'll then be able to use eehack, a powerful diagnostic tool to do real-time data logging and see why your car is misbehaving. I do have a few spare PCMs that you can use if you can't afford downtime.

How much? Please see ISSF, for further details.
Go shopping for injectors and you'll see this the same price as having yours tested, and far cheaper than buying new injectors anywhere else, and you STILL won't have all the needed characterization data, even from big name suppliers like Racetronix or Fuel Injector Connection.  Injector Dynamics includes full characterization data with their injectors, but they charge over $1000 for it. Nor will you get any help putting the data into your PCM.

If you need a PCM, core charge is $100, refunded when you return a working PCM. Or, if you have the cable, you can download and email me your current BIN file and I will update the injector data and email it back to you. I can also do mail order tuning if interested. The reflashing process with flashHack is nearly fool-proof, only 7 seconds of vulnerable time, and much faster upload times.

Why no love for the '96s?  Programming support is much more limited. But, if there are any computer/tech guys out there that want to help me, a solution is not far away.

If you're interested, send me a PM and we can discuss more.


Pricing Update with Link: Please see the ISSF for price and further details.
https://www.impalassforum.com/threads/fs-better-injectors-for-lt1s.1318911/#post-12124635

I responded to your PM with a PM last night but it is stuck in my outbox. I just resent it and it too is stuck in my outbox. Here is what I said:

I hope this isn't a double post. I replied to you via messages and it is stuck in my outbox. Here it is again:

As far as I know I'm still going home on Tuesday night. Any time after that will be OK.

My cell number is 410-615-2615.

I need to get my buddy to get a battery for me and install it. No way can I lift a battery right now. I hope that happens this weekend. I'll order tags for it and install them as soon as they get here; never should have taken them off and never should have take the door panels off all at once. It was so hoopty with no door panels that even my sister commented, and she is far from being a prissy woman. Anyway, that was probably the only reason I stopped driving it and I'm sure some stuff has gone wrong from just sitting. I'm going to carefully peel the woodgrain insert from the tailgate portion that mounts the tag before I put them on. I hope that goes well. Then I'm going to drive it for a while and fix any small  things that have gone wrong. I will be going over the engine for any new vacuum leaks and fix exhaust leaks, if any, and then implement my idea for home-made CAI Mk2. Once it is running very nice I'll download the .bin file for you.

Is there anything else I need to make sure of before sending the file?? I am going to get a mail order tune but I don't want to do that before I change out the rear end gears. OTOH, if I were to get proficient at uploading the file to flash the computer (I forget the name of the application) then I could compensate for the gearing myself. Does this sound OK? I want to do things in the correct order.

I'm home now. You can send the injectors any time. Stuff is still stuck in my outbox.

Please see ISSF for price and further details.
https://www.impalassforum.com/threads/fs-better-injectors-for-lt1s.1318911/#post-12124635

Hey guys, just an update; I do still have a few sets of the 36lb injectors for sale. The link above has prices and more info.

I've recently been made aware that Racetronix sells "drop-in" injectors for LT1s. They are dimensionally identical and the nominal flow rate is the same. Price below is for one injector.

https://www.racetronix.biz/p/24-lb-hr-disc-high-z-fuel-injector/d1810xx

I do not know if the spray pattern is different. Older injectors tended to have more of a stream than a spray; newer design injectors have much more of a spray. In port fuel injection applications, the amount of unvaporized (liquid) fuel that ends up on the intake manifold walls is modeled in the PCMs (including the stock LT1) in terms of fuel puddling and fuel boiling. In steady state operation, the amount of liquid fuel remaining on the walls is constant, but not during rapid throttle transitions.  If the values in the PCM are wrong, this can result in stumbling due to momentary air-fuel ratio swings. If you're still tracking with me here, just know that if you suddenly get a tip-in stumble you didn't have before, your fuel puddling and boiling tables in your calibration may need to change.

ALSO - I am not on this forum very regularly; I am a moderator over at impalassforum.com and spend more time there. I think there's an option to email me from this forum, and I'll get your message pretty quickly that way.