Discussion: E85 N/A Performance Gains
I've been contemplating playing with some E85 in my N/A BP4W next season especially after seeing the results the 949 guys are having on their NA8 motors. If you haven't seen the thread on m.net here it is;
[NA] 135whp with stock NA8 long block - MX-5 Miata Forum The TL : DR, 135whp on a healthy NA8 with stock header, 137WHP on a not so healthy NA8 with a RB header. Both cars have a completely stock fuel system and injectors sans Megasquirt. My goal is to see where I can take my BP4W which is already making ~140whp on watered down CA 91 and share the information with everyone. I've seen both sides where some say to replace rubber lines, injectors & fuel pumps and others who swear on replacing everything. One consistent piece of information I have found is that replacing your fuel filter after a few tanks is critical to prevent it from being clogged. Does anyone with experience in long term use of E85 want to chime in with anything they have learned? A major discrepancy I've noticed is the methodology for changing your fuel map. Some folks use their existing VE map, multiply by 1.3 and from there the information seems to get muddy. Other's change the req fuel number to increase everything and fine tune from there. I do understand that all my enrichments and cranking information will need to be changed as well. What is the recommended best practice for setting the map up for E85? |
I like it. Use it on all my fun cars now.
You absoulutely do have to upgrade the injectors though. I haven't replaced the filter before and had no issues whatsoever, but from what I've seen and heard, its probably a good idea, even more so on a high mile/older car. Its so cheap and easy too, why not. I've used both strategies - the latter works best. Bump req fuel by 30%, then fine tune. Both my 00 and my current 01 love the stuff. |
Originally Posted by 18psi
(Post 1077060)
I like it. Use it on all my fun cars now.
You absoulutely do have to upgrade the injectors though. I haven't replaced the filter before and had no issues whatsoever, but from what I've seen and heard, its probably a good idea, even more so on a high mile/older car. Its so cheap and easy too, why not. I've used both strategies - the latter works best. Bump req fuel by 30%, then fine tune. Both my 00 and my current 01 love the stuff. I was leaning towards the req fuel, thanks for the info. I am excited that I found out that my local E85 station has a year round 83% blend so I will not have to deal with the seasonal blends I've heard about. |
You know what, I guess I'm wrong on the injectors. Reading that thread now, and apparently the stockers have enough headroom for e85. I'm very surprised, but if Emilio did it on more than 1 engine, then I guess it works.
I guess I under-estimate how little fuel these engines need when properly tuned ( ie: not going pig rich in open loop) Yeah this stuff is great. I haven't ran into knock yet, and I've tried some really interesting things with my timing and vvt maps lol |
Originally Posted by 18psi
(Post 1077066)
You know what, I guess I'm wrong on the injectors. Reading that thread now, and apparently the stockers have enough headroom for e85. I'm very surprised, but if Emilio did it on more than 1 engine, then I guess it works.
I guess I under-estimate how little fuel these engines need when properly tuned ( ie: not going pig rich in open loop) Yeah this stuff is great. I haven't ran into knock yet, and I've tried some really interesting things with my timing and vvt maps lol |
I haven't pushed it on this 2001 setup, but its at 36 now up top. Doens't feel any faster if I keep going, so I stopped. No real dyno testing though, just a virtual dyno plot. Feels a whole lot quicker than stock though, that's for sure.
With your lower compression, you can probably push it even more. |
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Hmm interesting, I am interested to be able to quantify all these gains. I also plan on doing one last dyno with 91 before to have a starting point(I'll be using the same dyno for each test). For science this is my current 91 map.
https://www.miataturbo.net/attachmen...ine=1385496757 |
No need to replace all the lines. You may need to do the fuel filter, all depends on how much gunk accumulated in your tank over time. Mine is pretty clean inside.
You should either change the ecu's stoich value if that is an option, if not, change the injector scaling by 30% (believe this is called required fuel in MS). |
Not too long ago Grassroots did an article where they dyno tested an N/A, NA Miata, running MS with a bunch of different fuels, including E85.
The E85 made some significant power. This isnt news, but since some MTnet users have a phobia of theory; there is the hard data as tested on a Miata. |
Originally Posted by Leafy
(Post 1077094)
No need to replace all the lines. You may need to do the fuel filter, all depends on how much gunk accumulated in your tank over time. Mine is pretty clean inside.
You should either change the ecu's stoich value if that is an option, if not, change the injector scaling by 30% (believe this is called required fuel in MS).
Originally Posted by Full_Tilt_Boogie
(Post 1077100)
Not too long ago Grassroots did an article where they dyno tested an N/A, NA Miata, running MS with a bunch of different fuels, including E85.
The E85 made some significant power. This isnt news, but since some MTnet users have a phobia of theory; there is the hard data as tested on a Miata. |
Your wideband just sends a voltage to the ecu, the ecu interprets it as some lambda value. It needs the stoich value in the fueling calculations. I believe the stoich value, injector size, and engine displacement are all wrapped up into 1 variable on the MS, required fuel. In some ecu's they all have their own value since they are their own constants in the VE fueling equations.
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Originally Posted by Leafy
(Post 1077125)
Your wideband just sends a voltage to the ecu, the ecu interprets it as some lambda value. It needs the stoich value in the fueling calculations. I believe the stoich value, injector size, and engine displacement are all wrapped up into 1 variable on the MS, required fuel. In some ecu's they all have their own value since they are their own constants in the VE fueling equations.
I dig a little digging and someone on a BMW forum(BMW M3 Forum (E90 E92) - View Single Post - Compared: 87 E10, 93 E10, 93, 100, 105, E85 and M1) posted the results; Grassroots Motorsports recently tested 87 E10, 93 E10, straight 93, 100, 105, E85 and M1 Methanol on a Miata with a standalone computer and tuned each on a Dynapack dyno to make the most power with the fuel. The differences results were not dramatic except for M1 Methanol: 87 E10 made 135 hp and 117 lbs tq 93 E10 made 136 hp and 124 lbs tq 93 made 134 hp and 122 lbs tq E85 made 143 hp and 128 lbs tq 100 made 137 hp and 123 lbs tq 105 made 137 hp and 124 lbs tq M1 made 160 hp and 140 lbs tq |
If the required fuel has all that, then thats the value you change. The displayed stoich value in the tables is just that, something tuner stupidio uses as a conversion factor between the stored lambda data and what it displaces on the screen.
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Im currently piecing together parts for my e85 conversion on my CSP car, I got some 440cc rc engineering injectors, and now im thinking about the fuel pump. Do you guys think a Aeromotive 340LP would be a little over kill?
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Yes, stock should be sufficient, wally 190lp if you're feeling frisky.
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for n/a there's really no need for more than the 190
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I had a Walbro 190, and it died after 6 months. Walbro told me that it was my fault and wouldnt warranty it. They claimed without even looking at it that I had contaminated fuel. So I pulled the sending unit, tank was perfectly clean. Cut the fuel filter in half, no dirt at all. So fuck Walbro, not buying from them anymore. You really think stock is sufficient enough to flow enough e85 for racing application? Even though its n/a.
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Yes it is. You can either stay with the stocker or get the DW65 or DW200 if you really want to upgrade. Anything more might be a bit rough on your stock fpr and/or might overwhelm it
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Well I was planning on upgrading fpr as well. Obviously im not going for high hp here (shooting for 160 at the wheels) but im just trying to build a free flowing system with no restrictions so I dont have fuel pressure loss at high rpm. Im going to build my own dual feed rail with a nice external fpr.
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Sounds like a whole bunch of un-needed extra weight.
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The only extra weight is a couple rubber hoses and the regulator. The rail is aluminum which will be lighter than factory. I have plenty of weight to lose in other areas of the car.
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The m-tuned aluminum rail weighs more than the stock aluminum rail. You're also missing the weight of the fittings, and hose clamps which all add up. The stock rail and the stock regulator are the lightest setup and will not make any less power than what you want to put in.
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Originally Posted by 18psi
(Post 1081041)
Yes it is. You can either stay with the stocker or get the DW65 or DW200 if you really want to upgrade. Anything more might be a bit rough on your stock fpr and/or might overwhelm it
As an aside, I hit the dyno for one last number before I make the switch in a week. Car made 137whp/123tq on 91, however I did notice the duty cycle was showing ~73% near redline. I am starting to question if I need injectors, the most cost efficient would be re-manufactured RX-8 injectors from RockAuto ($130 a set). I may give it a shot without them at first, but it's something to keep my eyes on. |
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For those that are interested I took the plunge 2 days ago and made the change to E85. I ordered some GB Manufacturing RX-8 injectors from RockAuto. $155 shipped to my door and they are re-manufactured Denso. Swapped these in, made sure nothing leaked and ran the car nearly dry. Obligatory picture of injectors.
https://www.miataturbo.net/attachmen...ine=1388010749 After looking like a moron driving my car endlessly around my neighborhood with fuel jugs in the car I got the car nearly sputtering and shut it off. I filled with 5 gallons of E85 and it fired up. I altered my req fuel by changing the stoich number from 14.7 to 9.76 and everything worked fairly well. I got the car drivable and went straight to the E85 pump 5 minutes away and filled the tank up the rest of the way https://www.miataturbo.net/attachmen...ine=1388010749 For the fuel map I left my AFR targets at 12.8 for my 100kpa rows and left my timing the same. I will be on a dyno within a week or two and from there I'll start playing with a leaner mixture and more timing. I have noticed I need to decrease the cranking pulse in the colder areas, it really sputters at first and doesn't always catch. I attached my map if you care to look at it, I've noticed the injectors are at about 57% duty cycle with the car as it is. |
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