E85/E47 on a JBody ECU - Tuning Forum

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E85/E47 on a JBody ECU
Sunday, January 07, 2018 7:18 PM
So in the past I have been against running E85 on the factory Jbody ECU. I know a small handful have done it fairly successfully. I was really against how it has been done. Using a fake injector constant to trick the ECU into adding more fuel. Because of this I would not try.

This past year after dealing with some of my own tuning issues and injector issues. I came up with a idea of trying E85. I wanted to prove if it could be done successfully, but also without faking the ECU.

Because I did not have enough injectors and not having E85 all around me in my area. I decided to try E47. Also research shows that the possible HP difference between the 2 are minimal.

So my car has been running on the GM LD9 reflash for years. I'm running 60lb injectors. I left my injector constant alone. I used the injector pulse width multiplier to add my roughly 10% more fuel to my tune. I started with adding 8% and after some driving and watching my fuel trims I had to add a little more. Close to 10%. Then just some fine tuning of the VE tables. I dynoed the car this past Friday. Same Dynojet I have used for years. Gaines 19whp and and 23wtq. Final numbers of 241whp and 259wtq. Only changes to this setup from last dyno was Different injectors (went from 80's to 60's because of a sealing issues). I have not had the chance to figure out my gas mileage yet. It appears cruising it is not far off, but under WOT she drinks. I'm maxing out the 60's on this setup.

I still have some fine tuning to do on the cruising part (need to fix my exhaust leak first).

I will say I was wrong in the past and you can do it. The way I did it I feel is the best way, but I also know that the IPW table is not available for all years. I believe 99 is the first year with that table. I did have a cold start issue at first, but have been able to tune that out.



FU Tuning




Re: E85/E47 on a JBody ECU
Wednesday, January 31, 2018 3:48 AM
I'm curious to see what the end result is. I have been contemplating switching to E85 in the future and if there is a better way to do it then I might end up doing it after all.
Re: E85/E47 on a JBody ECU
Wednesday, January 31, 2018 10:39 AM
First, I hate you for having a real 2 bar tune, however rudimentary it may be.

Second, I'm guessing this is your ld9 M45 car?

Third, I have some questions about the IPW multiplier table in the LD9 reflash. Does it go past 0 vac on that tune or can you only adjust up to there? I need to look at it when I get home today.

I'm curious if you've ever experienced the IPW multiplier issue at 0 vac like I've seen in the eco cars. If you bump that number too high, and by too high I mean anything past 1.1 and sometimes even less, they run like a bag of dicks at 0 vac to ~5psi. Stumble, run rough, and just in general carry on. And this is even if the AFR is spot on.

Now, that could also be related to using a 1 bar tune and having crap options for timing at those pressures/throttle positions. But I've found that backing that back down to 1.0 or close to it fixes the issue. Then I have to go crazy with ve offset and ve tuning to get it right. Time consuming but has, and continues to, yield the best results.



"In Oldskool we trust"
Re: E85/E47 on a JBody ECU
Thursday, February 01, 2018 4:09 AM
Y3llowCav wrote:

Second, I'm guessing this is your ld9 M45 car?.

I believe it is on his M62 LD9, with the M45 GM Re-flash.

Adding fuel this way makes me feel better, but what is the car running while cruising. Air fuel wise?





Re: E85/E47 on a JBody ECU
Monday, February 12, 2018 5:51 PM
aaron garcia wrote:

I'm curious to see what the end result is. I have been contemplating switching to E85 in the future and if there is a better way to do it then I might end up doing it after all.


What end result? Still running on the E47 mix. Car is running very well.



FU Tuning



Re: E85/E47 on a JBody ECU
Monday, February 12, 2018 5:55 PM
Y3llowCav wrote:

First, I hate you for having a real 2 bar tune, however rudimentary it may be.

Second, I'm guessing this is your ld9 M45 car?

Third, I have some questions about the IPW multiplier table in the LD9 reflash. Does it go past 0 vac on that tune or can you only adjust up to there? I need to look at it when I get home today.

I'm curious if you've ever experienced the IPW multiplier issue at 0 vac like I've seen in the eco cars. If you bump that number too high, and by too high I mean anything past 1.1 and sometimes even less, they run like a bag of dicks at 0 vac to ~5psi. Stumble, run rough, and just in general carry on. And this is even if the AFR is spot on.

Now, that could also be related to using a 1 bar tune and having crap options for timing at those pressures/throttle positions. But I've found that backing that back down to 1.0 or close to it fixes the issue. Then I have to go crazy with ve offset and ve tuning to get it right. Time consuming but has, and continues to, yield the best results.


Sorry I have the crappy 2bar. lol
This is my LD9 with M62 on the GM LD9 reflash.
Yes it goes past vac. It goes all the way to 210kpa actually.
I have not run across the issue you are talking about. I usually do 1.0 across the board. In my beginning years of tuning I would jack the VE offset up, but I never do that anymore. I have found that 1 a properly setup fuel system should not require it, and 2 I can play with the IPW to get what I need.



FU Tuning



Re: E85/E47 on a JBody ECU
Monday, February 12, 2018 5:59 PM
-MD- Enforcer wrote:

Y3llowCav wrote:

Second, I'm guessing this is your ld9 M45 car?.

I believe it is on his M62 LD9, with the M45 GM Re-flash.

Adding fuel this way makes me feel better, but what is the car running while cruising. Air fuel wise?


My cruising AFR's are spot on 14.3-14.8. I put in a new sensor for my LC1 when I started this process. This was the first time the sensor had been replaced since my LC1 has been on the car. I do not know if it is the new sensor, or the E47, or a combination of the 2, but it has tuned soo easy on this setup. We have had some cooler weather than normal in Florida this winter (lol I know), and I have noticed a very slight cold start hesitation. It is common that on E85 cars can be hard to start when cold. I would not say my car is hard to start, but if cool enough It will turn over a extra time or 2 before cranking and you can hear it slightly struggle. It was worse and I was able to tune it better and might be able to more, but this is nothing that concerns me. It does start everytime.



FU Tuning



Re: E85/E47 on a JBody ECU
Tuesday, February 13, 2018 8:01 AM
John, now that you went this far, how would you feel about E85? Do you think with larger injectors, you could tune it the same way?




Re: E85/E47 on a JBody ECU
Tuesday, February 13, 2018 9:42 AM
Addicted to meth wrote:

Yes it goes past vac. It goes all the way to 210kpa actually.


I hate you.



"In Oldskool we trust"
Re: E85/E47 on a JBody ECU
Tuesday, February 13, 2018 2:18 PM
-MD- Enforcer wrote:

John, now that you went this far, how would you feel about E85? Do you think with larger injectors, you could tune it the same way?


I do. I was going to run E85, I did not because I did not have the room in my injectors. I could not justice the cost for 80's for this test. I think the same overall results would be had. It helps having a good solid tune on normal gas already in place.



FU Tuning



Re: E85/E47 on a JBody ECU
Wednesday, February 28, 2018 7:16 PM
i miss seeing these old time folks on jbo, makes me all nostalgic. i really need to boost my new j finally




Re: E85/E47 on a JBody ECU
Friday, May 25, 2018 4:17 PM
Addicted to meth wrote:

In my beginning years of tuning I would jack the VE offset up, but I never do that anymore. I have found that 1 a properly setup fuel system should not require it, and 2 I can play with the IPW to get what I need.

So you're saying you use the IPW Multiplier to manually increase your fueling, and then modify the VE tables after collecting AFR error data? This way it prevents the necessity of going to higher than ordinary VE.


2001 Alero 5-speed: GT3076R @ 21 psi
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