Cosmos

iTrader: (15)

When tuning for E85 , do you want to upscale your Injectors? Example......my car runs 42lbs but my tuner (good friend) has them upscaled to 53lbs in the tune due to the e85. We are going to retune this week and I'm trying to educate my self further on tuning to get the most out of my car. Thanks

MikeyZ

iTrader: (20)

thats a horrible way to do it... do it right...

oange ss

iTrader: (50)

find a new "tuner"

Cosmos

iTrader: (15)

I just found out today that my injectors are 50 lbs at 58 psi, not 42. I don't know if he still upscales the injectors but I know he did that in my other car back in 07. He does it on the side and doesn't charge me anything since he is always learning and my cars have always performed well so I'm not worried. Do you guys have any tips or advice I could pass along? Would be greatly appreciated.

Cosmos

iTrader: (15)

Also, why is scaling the injectors for e85 a horrible way to do? Just curious.

salemetro

iTrader: (5)

This seems a little mis-leading. What rail pressure are you running....and what size injectors@ 43.5 psi flow rate?

I'm guessing that you are using 42lb injectors (rated @43.5psi rail pressure), and feeding them 53-ish psi of fuel (stock ls1 fuel pressure). So, your tuner is "scaling" the injectors that were rated @ 43.5 to reflect a more accurate "real-world" flow rate with the amount of pressure they are actually being fed. It really has nothing to do with the E85. He's just trying to input an accurate flow rate at an accurate rail pressure.

If this is the case, this seems normal to me. Anyone else?

edcmat-l1

iTrader: (10)

Telling the computer the injectors are bigger than they are, will lean it out, not fatten it up. Bigger injector flow rate, less on time, less fuel. Exactly opposite of what you need running E85.

E85 has a stoich point of roughly 9.8:1. About 30-40% more fuel requirement than petrol. First thing you should do is change the stoich point in the tune. Leave the injector flow rate alone.

So, basically, the guy tuning it, is an idiot.

Cosmos

iTrader: (15)

I could be completely wrong ob what he told me he did, it was over 5 years ago that he told me when we tuned it. I could be the idiot and not remember correctly. My afr is spot on and I've always had one of the fastest NA 346s around and never had problems with the tune so he is doing something right. I'm just gathering info.


Spot on salemetro. That mcould have been what he was talking about and I took it wrong.

salemetro

iTrader: (5)

But what if he's telling the computer the corrected flow rates based on the increased rail pressure? See my post above, but I'm just guessing that's what he's trying to do. It seems that some key information might be missing/misunderstood from the OP.

BLK02WS6

iTrader: (2)

No, you don't change injector tables for E85...

Slowhawk

iTrader: (12)

I've seen it the other way like this. 42lb injectors scaled as 36's for E-85.It's ussually 30% richer.

Alot of people will just scale the injectors right then work the VE table for the A/F ratio needed. Depends on the computer on which way I would go about tuning in E-85.

salemetro

iTrader: (5)

This seems the most accurate way to me. Wouldn't you lose some resolution by scaling an injector to be "smaller" in the tune? I suppose it might be close, but do you think that it would effect driveablity much?

Just trying to gain some insight here.

Cosmos

iTrader: (15)

How would you scale them in a 00 ls1 pcm slowhawk?

LSxPwrDZ

iTrader: (4)

The correct way to do it is to input the correct data for the injector because it is a constant. The only time I ever tamper with injector flow rate is if I'm scaling the tune to broaden the 512g/sec limit on MAF setups.

Set the Stoich AFR of the fuel and the PCM will correct fuel delivery! Ed is right!

salemetro

iTrader: (5)

But it seems that we might be talking about injectors that were rated @3BAR....being fed 4bar of fuel pressure. If the only data available is for 3bar pressure, then the tuner would HAVE to scale the injector flow tables to get in the correct range.....THEN set the stoich AFR of the fuel being used.....THEN work the VE tables if desired. I don't think the tuner even tried to scale for E85...as he went the wrong direction. I think he scaled the flow tables for the increase in fuel pressure.

That's what I'm meaning about the info being very vague/misleading in the first post. There seems to be information missing....

moehorsepower

iTrader: (3)

Please explain loss of resolution,

salemetro

iTrader: (5)

Meaning that scaling an injector vs entering correct/accurate flow data might not be the best way to go. It's my thought that when scaling, it's possible to lose accuracy/resolution in the tune. That's why I posted the question, as I'm just starting to wrap my brain around tuning concepts.

Honestly though (to the OP)...and I mean this in a positive way....

If you don't have any plans to "dig in deep" to tuning concepts/principles....and you've had good luck with your current tuner (ie; car runs solid, good afr, etc...)....why would you second-guess him? I can understand if the car was/is running like crap or has issues..... But you stated earlier that he's always done a good job for you, so I'm not understanding the second-guessing.

I'm also curious as to why you're switching to E85...is your car FI?

Mike@Diablosport

iTrader: (2)

Exactly, the less 'lying' you do to the PCM, the better off things are. If you can tune it without lying to it, then thats always the way to go

PCMs are not as dumb as some people think....

LSxPwrDZ

iTrader: (4)

Maybe I mis-read you but to me that is not scaling. If you are using the 42lb green top injectors they will flow right at 52.5lb/hr at 58psi. So that is probably what your tuner did back in the day to correct for flow rate at different rail pressures, however that is still a constant.

My post was mainly referring to the use of scaling the injector table 30% or so to compensate for e85. That is the WRONG method of tuning e85 on a LS PCM/ECM. The Stoich AFR in the tune is there to be used to calculate the amount of fuel mass is needed for the measured/caluculated air mass the engine is using. Lying to the PCM to get the injector pulsewidth right for a certain condition will cause issues later down the road. The more accurate the airflow tables are the more consistant your tune will be. Out in the real world without all the fancy test equipment OE's have the only way of doing this is to rely on lambda readings in the exhaust. That measurement is dependant on the fuel data the PCM is supposed to KNOW itself.

Think of the engine controller as being a huge calculator. You have X amount of air coming in and the PCM knows it needs Z ratio of air and fuel (based on the Stoich ratio and the equivalent ratio of that stoich). It then opens the injector Y amount of time to give it's correct mass of fuel to match that ratio. The problem is when you start tampering with "funny" injector data you get results that aren't accurate on your airflow tables (VE and MAF). This is why the constants in the calibration must be kept just that constant.

Cosmos

iTrader: (15)

Salemetro, this came about because I was getting horrible Mpgs. I wanted to do some of my own reaseach to educate myself a little. Been on korn since 07.

I misunderstood him. He does not upscale the injectors for e85. He tunes it just how you should as mentioned in this thread. He looked at me like I was retarded for asking him that lol.