I see them recommended in many places, but now it seems everyone says they suck because there's no data available for them for tuning?

Can someone explain in plain terms if they are useable or not? I finally got a set and I have HPTuners, but now I'm totally regretting the 8.1 marine injector purchase after seeing everyone all over the board with the values for HPTuners.


Thanks!

 

You just have to tune them the "old fashioned" way...which a lot of guys will now argue is incorrect...you have to do your own math to figure out what numbers belong in the IFR table (not a big deal) and what the min pulsewidth and all the offset stuff is...it's doable...you just can't look up the data and copy/paste...a lot of new tuners only know how to copy/paste.

A friend is running them in his car, they're tunable...I tuned them (not done yet, the car isn't 100% yet so I can't get the tuning time in on it yet)...and they work very nicely...you're fine.

 

So they are just as good as any other 44lb injector, but you just need to work more? Not a problem by me!

 

Yup, you just can't copy and paste...and to be honest...yeah I like that injector values are available for lots of injectors now...but once in a while, external circumstances affect that calibration, and a LOT of people don't want to realize that because they're copy and paste tuners. Not all injectors are identical...there are tolerances in any manufactured part. Some of them are very high tolerances...but still...all the hardware inside of them isn't always nominal to design/print...if you can't make those minor tweaks to the calibration after copying and pasting the data, yeah, you can't tune for a set of 8.1 marine injectors on your own either...but if you've been tuning for more than the past few years (like when software was all in dos...sometimes we were lucky to have a way to get the code out to hex edit it ourselves)...you can tune a set of injectors...even GM has differences in their tunes for it...I just tuned a 1999 TA for a friend tonight...and it's got SLIGHTLY different injector cal data from another friends 1999 SS...both of which had STOCK flashes in their PCM's...they have differen't OS numbers, VERY slightly different data...and the SAME part numbers on their injectors...

They idle nicely, they seem to me to have a good spray pattern...and they flow what they're rated to flow...not sure what else you need from them other than to spend a little time tuning them.

 

Thanks Mike, feeling better about it already!

 

8.1 marine injectors are multec 2 style, 1999-2005 GM LS trucks use same connector. The connector is unique to it. If you need a decent injector for GM truck up 450rwhp, blower etc. its a good option. Otherwise typically solder on EV1 connectors to install 60lbs injectors.

 

Thanks - I mainly wanted them for plug and play ability with harness and fuel rail connections, but they should be sized about right for what I have.

Just got a little shaken when searching for info on injector data, but sounds like everything will be OK

 

What about having 8.1 truck injectors resized? In that process, would they come back with an exact IFR figure?

 

Anyone else have anything new to add?

Thanks!!

 

I read the calibration in a hummer with a supercharger on it, had injectors 17113739 in it. After fixing a very large vacuum leak (brake booster port) It idled with fuel trims near 0.

 

I'll try those, my tuner tried, but my long trims are way fat between 14-17 (HP Tuners) during cruising.

 

Hey, I've been looking for the injector characterization data for those 8.1 Marine injectors. Any chance you could email me a copy of that factory Hummer tune that uses them, or upload them to the HPTuners tune repository and send me the info on where to find them?

I would like to get the voltage compensation tables and other remaining data. Thanks!

 

Bumping a really old thread here, but does anyone have any more detailed information than this? I just picked up a set of these and I'm looking for some reliable data to start with.

 

looks like I forgot to post the Injector offset table from above. These are export files straight from HP Tuners, from a H2 hummer I personally read the calibration from, and had the above mentioned injector part#.

 

That's odd that the default injector pulsewidth data you have has so many zeros in it; 0 from 3600 on up.

 

I have read two PCM's from supercharged 6.0L hummers. One was in my driveway, the other sent me the PCM to make some changes to some DTC's. I just compared the two and the injector settings on both were identical, all 5 tables.

 

I wonder if some of the data has been skewed to work with the supercharger better. I've looked really hard for solid data, and yours seems like the most complete I've found yet.

 

After looking at multiple different radix and magnacharger tune files, it looks like they cheat the tune using the IFR tables. So, unless you're running a supercharger, those numbers aren't going to work well. The Flow Rate vs. KPA should be 43.8 for a return system. Think I have a good starting-point though.

 

Sorry to bump an old thread, but had a few questions on how the data hear worked for you? I'm running a non return setup (corvette FPR) and was wondering how much this data needs to change to work with it? Thanks in advance.

Rob

 

Can't help you much on the non return, but using the stock truck injector info and changing only the IFR worked well. But I was unhappy enough with part throttle tuning that I bought some different injectors with good known data when i switched to the FAST intake. My marine injectors are sitting in a box and are for sale if anyone wants them.