suplemental fuel system

1187 Views 12 Replies 4 Participants Last post by repforenzo, Jun 8, 2009

raybel

Discussion Starter · Jun 6, 2009

I’m running my car with stock engine and stage 1 SDS. I have the injectors that come with the sds kit but I also have the supplemental fuel system not working now. I would like to star running my car with those supplemental injectors also plus the other ones to get richer my car. I want to run just with ethanol no gas to get better result. I need help how I can run two different maps for injectors system and if you guy think that I really going to see different doing this??????????????????????

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repforenzo

· #5 · Jun 6, 2009 (Edited)

I don't think you are listening to us very well. What your friends 350Z can do, may not work well on your car. Bitter made two good points: you gas mileage will go down because of because of the stoitchmeter of ethanol and you fuel components need to be able to handle the destructive nature of the fuel. The tuning will change dramatically, because the ECU in closed loop is looking to maintain 14.7:1. That would be too lean for E85. You need to know this stuff.

I suggest you get the car working properly on gas. Then you can move on from there.

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repforenzo

· #7 · Jun 7, 2009

raybel said:
Thank you guys for advice

Sure, happy to help. I do have one question that wasn't clear in your first post. Ripps current stage 1 setup has the stock injectors in place with the supplemental injectors adding fuel during boost. It seems like you have replaced the stock injectors with bigger ones and are about to engage the supplementals. Is that the case? I don't think that will work well with the current tune of the BB and BRAT. You end up running rich and whacking out your LTFTs. Meaning idle will suck and cruise will suffer. Keep the stockers in place if you plan to use the stage 1 setup as is.

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repforenzo

· #9 · Jun 7, 2009

What is going on is your car still 'thinks' it has 210cc injectors in it. So the injectors you have in there are dumping too much fuel causing your LTFTs to go way negative. The BB won't help this situation which is why Ripp went to the supplemental injectors setup. You have two choices: put the stockers back in or scale the current injectors properly with the ECUflash.

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repforenzo

· #11 · Jun 8, 2009

raybel said:
Can you help me to scale the current bigger injectors that I have with the ECU flash? If you are busy I understand

I can't do that for you over the forums. You need to be able to log your LTFTs and then do this process:

You scale it to a lower number compared to the new injector size, not the old injector size. The larger the injector, the larger the percentage difference. For example: stock 4 cylinder injectors are 240cc's and the injector scale is set to 232. That's about 3.5% lower. I am running 450cc's and my injector scale is 401. That's a little over 12% lower. Get it?

First, since you are puting in larger injectors, they take longer to open then smaller injectors. So, you have to change the latency values. I havent come up with a systematic way of doing this, but making your values 0.1 lower across the board should put you in the ballpark for your injectors.

After you do that, set the injector scale to a lower value than the new injector size. 5% lower is a good place to start. Now monitor idle fuel trims. Just make sure your long term fuel trims are 0% and your short term are with +- 10%. Once you get it in that ballpark, go for a drive. Cruising fuel trims are what you need to tune for, not idle. Adjust the value as needed to maintain 0% long term and as close to 0% short term as possible. Less than +-5 percent is great. Anything other than 0% long term in not acceptable.

After you get that straight, monitor the car at idle again. If the short term are a little out of whack, use the injector latency settings to get them as close to 0% as possible. Again, anything other than 0% long term is unacceptable.

While you are doing all of that, make sure you aren't messing with any other parameters. That's all there is to it.

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repforenzo

· #13 · Jun 8, 2009

PharmEcis said:
Phil, aren't you getting tired of repeating yourself? You go harder on the n00bs over on the org than here. :lol:

Yeah, but every once in awhile I mellow out. However, I think I'm done at this point.

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