80# injectors and return fuel system?

[ionredline06]

Setting up 80# injectors and return fuel system on an LSJ? How do I setup the injector tables?

[CarsonTech]

Not sure if this is accurate or correct, as I haven't tried it yet. I want to to something similar when I get my 80's.

Take a look at this.

http://www.hptuners.com/forum/showth...852#post128852

[skatinboarding]

That works but dont use the same injector settings that he used because he is using 60lb injectors.

[CarsonTech]

Truf

[csementuh]

Depends on your fuel pressure...

80's flow...

Static Flow Rate: 80 lb/hr at 43.5 psi
Static Flow Rate: 92.38lb/hr at 58 psi

Soo... If you need the higher pressure and flow for E85, go with a 58psi base pressure, if not use 43.5psi. You could probably use any other value, and use the HPT built-in fuel injector calc, but that wouldn't be perfect unless you had the injectors flowbenched.

For 43.5psi, it's easy as voltage modifier is 2 and injector flow rate is 40 for 80lb/hr total.
For 58psi, I used voltage modifier 2 and IFR of 46.19016 to get the 92.38lb/hr flow.

Follow the lead from the 60's return style tuning tutorial posted about to see how to setup the the Offset vs Volts vs VAC table using the proper pressure offset. For the 58psi you copy the -1 column and 43.5psi uses the -108 column if I remember correctly.

It's really pretty simple once you understand the background on it. You're basically just making your injectors a set size to the PCM based on fuel pressure, and then keeping it constant while letting the fuel pressure regulator do the work of making the injectors bigger or smaller based on engine vacuum or boost.

Can anyone add anything..?

[csementuh]

Bump for info!

ZZP is arguing with me about tuning their BRFPS. It's the same as the return style in (opt 2) so the tuning should be the same. They claim the injector flow rating should maintain a sloped line, and make no mention of modifying the table for the base pressure offset.

Can anyone shed light on how their BRFPS is tuned?

[5_Liter_Eater]

If you have a boost/vacuum referenced fuel system then the IFR should be a flat line. The number of the flat line would be determined by the injectors rated and running fuel pressure.

[csementuh]

That's what I said! lol

80's flow 80lb/hr at 43.5psi, so 2 is the voltage modifier, and 40 is the IFR...
Then you need to adjust the Offset vs Volts vs VAC to be the same for all columns using the data from the column corresponding to your new base pressure offset. For example, 58psi stock base - 43.5psi new base = 14.5psi = 99.97KPA, so you use the -101KPA column since you're dropping ~100KPA off the stock base pressure.

That sounds right, no?

Ref... http://www.hptuners.com/forum/showthread.php?t=18009

Here is what ZZP said...

"AFter going boost referenced as option 2 (recommended), you want to basically keep a similar fuel chart to what you had but flatten the line. In our experience, not toally flat. Just take that slope if it's going from 40-60 over the chart and cut it to 50-60 or something like that.

Of course you should adjust the voltage for larger injectors too since the chart doesn't go far enough to do it all in the injector chart but this is stuff ZZP isn't offering support on. Buy our PCM if you want us doing it. Some people don't use the voltage modifier for 60+ # injectors and for them we'd have to figure out their file to get advice, esp if they changed the MAF. This is why we tend to keep the advice basic. It's not fair to ZZP to expect us to rework your PCM when you aren't buying the file from us. If someone bought our file, our BRFP, then we would help. it would be easy for us because we'd already understand the file and have base files to start from."

[5_Liter_Eater]

You are correct so I would ignore their advice which is pretty arbitrary anyway. "...basically....not totally flat....something like that". If confronted they would fall back on "from our experience" but you and I know how it should be set up.

[csementuh]

LMAO. I'm not sure if you know who ZZ Performance is, but generally they have a holier than thou attitude about everything... Their customer service is attrocious in my experience. I've bought stuff from them since 2006, and I only ever buy more because sometimes they'll make a part that's decent or nobody else has...

But, ya, I certain trust the guy with a 600+RWHP Z06, and people on here who actually know how to tune lol.

They were advising to not even check your fuel pressure, but to rather keep it at their pre-set 'about 42psi' pressure, and then just keep you IFR settings as a slope so the PCM would adjust it. Seems outlandish to me...

[csementuh]

bump

[skatinboarding]

Why you bumping this? I thought you got this running and figured out.

[csementuh]

Why you bumping this? I thought you got this running and figured out.

Welll, basically nobody with one of these ZZP kits has ever posted any tuning information on tuning it. A helpful guy in a Z06 reassured me I knew what I was talking about, but that doesn't fully help since he doesn't know the LSJ's. I am hoping someone with the ZZP kit will speak up, considering ZZP kind of says to tune it one way, and other people kind of say something different.

[5_Liter_Eater]

I don't have to know LSJ's. The effects of fuel pressure and manifold pressure on injector flow rate are universal.

[csementuh]

I understand what you mean, and I certianly wasn't discrediting your input in the the least. I simply was trying to see if anyone else knew anything more about the kit, and I was looking for their tuning experience with it. That is all.

[5_Liter_Eater]

I didn't think so. sorry if it came across that way. I just think you're overthinking it. Your new fuel system is vacuum and boost referenced so whatever pressure it is set for at atmospheric is what the IFR should be and it should be flatlined because the fuel pressure is changing to account for manifold vacuum & pressure. Done and done.

[5_Liter_Eater]

Oh, and it's not a Z06. It's got repro Z06 wheels and Z06 rear spoiler but thats it. I would like to do the Z rear quarters for the extra meat it affords but thats low on the list right now. The fact that it gets mistaken for a Z06 is perhaps reason enough to get some new wheels. Even lower on the list.

Anyway, I would stomp on a Z06 though. A ZR1 for that matter. Sig stats are not updated yet until I dyno again but I am expecting to crack 700 RWHP.

[csementuh]

Well thanks for the input, I certainly appreciate it.

LOL, no big deal. All of the newer Vette's are sick. I definitely need to consider one for a new project some day. You're setup looks quite fun! I'll have to check to see if you update a dyno thread or anything, as I'd love to see what it would do now. Good luck.

[skatinboarding]

Welll, basically nobody with one of these ZZP kits has ever posted any tuning information on tuning it. A helpful guy in a Z06 reassured me I knew what I was talking about, but that doesn't fully help since he doesn't know the LSJ's. I am hoping someone with the ZZP kit will speak up, considering ZZP kind of says to tune it one way, and other people kind of say something different.

I just was making sure you had it running still.

[csementuh]

Yes, it's running pretty good at the 43.5psi base pressure. Idle is nice. It seems to be putting the fuel more than high enough top end. Still need to find some time to get the tune dialed in though.