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Thread: Help with E85 race cam tune.

  1. #1

    Default Help with E85 race cam tune.

    Hello I wanted to see if I could get some advice on the new tune I'm trying to create (see attached tune and a current datalog). Engine is a SBF 347 stroker with Kaase P38 heads and large cam (lift intake .609" exhaust .587", duration intake 241°, exhaust 248°, 108° separation). It made little over 500 HP at motor with carb. Went with E85 because the remote tuner I hired to help get it to idle correctly (Holley base tune was not close) advised that the Super Sniper 1250 was too large for my N/A 347. I want with larger 1250 as I plan to eventually to with a supercharger on a Dart 363. So this tune is the base tune for 347 race cam with 35% increase to Base Fuel Table (lb/hr), Cranking Fuel (lb/hr), AE vs. TPS Rate of Change (lb/hr) AE vs. MAP Rate of Change (lb/hr). Not a lot of miles on this tune. I mucked up the last one so much, I started over. Also I have taken the car to a local performance shop in DFW area of TX called True Street Motorsports and they spent a good half day trying to get me a better tune, but end the end the tuner spent most of the time chasing the reason for huge POP on decel from WOT. They ending up removing a lot of fuel from the bottom of the table and then locking out the Learn & Closed Loop functions and saying my WBO2 sensor was bad. I installed new one from Holley and still have issues. Money down the drain. Thanks for any help or guidance that comes my way.
    sniper log 20190514-191953.zip
    sbf 347 race cam base tune convert to e85.zip

  2. #2

    Default

    I found one of the original tunes from the remote tuning before I messed it up, and it's a lot closer than the one I posted on the 14th. If someone would please take a look and let me know what/how I should adjust the Acceleration Enrichment fuel table modifier. Thank you.
    347 sbf progressive throttle e85 4-16 change 1 on 5-15.zip
    sniper log 20190516-201148.zip

  3. #3

    Default

    OK, let me see if can make this not so big of a request for help as my prior two posts. The remote tuner got back to me with a suggestion from my last datalog post on here and suggested the following.

    “In your datalog, monitor (turn on) both CL Status & Learn Status. You'll see that both switch off during throttle transitions, and when the throttle is steady, the fuel map is too rich. As a process: I'd first back off on the AE fuel for a while, in order to not confuse the Learning process. Then leave both Closed Loop & Learn, on and drive the car in STEADY STATE conditions, at various loads and throttle positions (totally ignoring and not expecting any throttle response) until the fuel map has been adjusted. Then add the minimum amount of AE fuel back in, to remove any lean stumble.”

    Thought I'd throw this follow up question on here to get thoughts and suggestions on how much to take out of the AE vs TPS & AE vs MAP? Thanks.

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    21,469

    Default

    See posts #8 & #9: http://forums.holley.com/showthread....9444#post29444 (EFI Acceleration Enrichment In Carburetion Terms)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  5. #5

    Default

    Does it look like I've taken enough out of the AE vs TPS & AE vs MAP to not corrupt the Learning?

  6. #6
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    21,469

    Default

    The Holley Sniper EFI will intermittently inhibit Closed Loop at idle, if the AE vs TPS/MAP RoC Blanking values are set too low (not necessarily the AE vs TPS/MAP Rate of Change values).
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  7. #7

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    It seems to be staying in Closed Loop all the time during idle. I started out with 15 & 15 for those values. That was how it was with the base calibration. I then changed them to what they are now based on a post on here. Should I move them back to 15 & 15? Thanks.

    Also, I noticed today that the area it idles in is constantly adding and then removing fuel. Could this be corrupting the map outside of the idle area"? If so, should I check the enable RPM To Enter Closed Loop and RPM To Enter Learn to say 1200? On a another note anyone know of a good EFI tuner in DFW TX? Thanks.

  8. #8

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    So I had a long conversation with the owner of the performance shop that tried to dyno tune my Sniper before and failed after roughly 3 to 4 hours working on it. The owner's explanation was that the Sniper does not have enough tunability to work well with my engine combo and that I should have went with the HP or Dominator instead. But he's more than willing to keep trying at $125 an hour, but makes no promises on the result. So if anyone has similar cam/engine combo that is successfully using the Sniper would you please reply with your combo, what you went through to get it working and any advice? I need to know if I should keep pouring money into someone tuning it or cut my loses. Thanks.

  9. #9
    Join Date
    Sep 2018
    Location
    Grand Rapids, MI
    Posts
    35

    Default Just some quick advice from my experience.

    I have a similar setup to you, but on a small block Chevy and with a less radical cam. Here's my quick advice and be aware this isn't coming from an expert: make sure learning is enabled and just put some decent miles on it! That method has actually been more successful - for me anyway - than pretty much everything else I've tried (including poring over tons of datalogs, searching forums day and night, etc). If the tune is close enough to make the car drivable, drive it and drive it and drive it. The "stock tune" with the adjustments for E85 you mentioned wasn't even close for my engine as well.

    I was chasing a lean stumble and driving myself nuts. Once I got the car out this spring, I've just been driving it as often as possible under mixed conditions (slow accelerations, some fast accelerations, lots of steady RPM driving) and the lean stumble has almost sorted itself out completely. I looked at the Learn Table for the first time last night and noticed that the system was having to remove about 20% from my base fuel table at high vacuum situations and having to add about 30% during low vacuum situations. This was after maybe 3 hours of total driving time without any fiddling on my part. And what used to be a WICKED lean stumble is almost gone.

    I updated my base fuel table with the learned data, smoothed things out a little bit, and put the new tune in the car. I'm planning to do a bunch more driving and see what changes next... working under the assumption that fewer and fewer learned corrections will be necessary as the base tune gets more accurate. Hope this helps at least a little bit!

  10. #10

    Default

    Thank you. I appreciate you taking the time to respond with your experience so far. Do you have the stock 1:1 throttle linkage or progressive linkage? I’m thinking I might switch back to the 1:1 linkage and see if it likes that better. I went straight to the progressive right from the start.

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