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 FS: Better Injectors for 94-95 LT1s

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Posts : 2300
Join date : 2009-05-28
Location : Huntsville, AL

FS: Better Injectors for 94-95 LT1s Empty
PostSubject: FS: Better Injectors for 94-95 LT1s   FS: Better Injectors for 94-95 LT1s Icon_minitimeThu Aug 20, 2020 12:56 am

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, 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? $195 shipped. 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.

rcktpwrd likes this post

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