Results 1 to 7 of 7
  1. #1
    It got WIFI and touchscreen ! PWCGUY's Avatar
    Join Date
    Jul 2009
    Posts
    216
    +1
    10

    How to Make Your 4Tec Start and idle Like Stock

    If you would like your 350 HP beast to start, idle and respond at lower RPM’s like stock then this is the thread for you. These MoTec adjustments are based on having a fuel map ( and ignition map ) which is already calibrated at normal operating temperature. If this is not the case then you should first get your base map dialed in and then proceed as follows. My setup has 1000 cc ID injectors and a stock 08 camshaft.

    Stock Idle and Starting Adjustments
    My goal was to be able to press the start button and have the motor start and idle ~ 1700 RPM smoothly without the need for throttle input from driver and then respond smoothly from idle and return to a smooth idle when releasing the throttle. I'm sure there are many different ways to accomplish this but here is the recipe that works for me. I will break this down into several categories of Fuel Compensation, Enrichment Adjustments and Ignition Compensation all of which are reflected in the .e35 attached.

    Fuel Compensation's - Obviously the motor wants more fuel during cranking, post crank and lower engine temp. I have experimented with the magnitude and profiles to optimize, nothing extraordinary here ( NOTE: in my map I have changed my engine temp units from deg C to deg F, sorry I'm a USA guy ). Also noticed that the post cranking fuel compensation was very sensitive to ignition timing so this adjustment goes hand in hand with the ignition compensation's mentioned below.

    Enrichment Adjustments - I made some slight adjustments to decel sensitivities that came with the plug & play map but much bigger changes were needed with the accel and decal clamps. Accel clamp 0 - 6000 RPM set to 18 and then dropping to 0 at higher RPM. Decel clamp 0 - 2000 RPM set to 20 and then dropping to 0 for higher RPM's. The other adjustment that helped was the Accel Threshold in the general setup. I lowered this from 50 to 10 which cleaned-up a stumbling issue I was having when slightly increasing TP from idle.

    Ignition Adjustments - Here's where things got a little more interesting..... at least to me. As mentioned previously base ignition advance needs to be ~ 0 deg at 1700 RPM for the motor to rum smoothly. However when starting the engine additional advance is needed even when its warm and more so when its cold. It took two compensation tables to accomplish this. I was trying to be careful in adding advance so as to protect the motor and get best performance if you did a full throttle pull immediately after starting ( NOTE: these compensation's together could be as high as + 7 deg ). The first table I used ( ET Comp Trim) has two axis one RPM and the other for temperature however the temperature I used was from the stock exhaust sensor at the waterbox inlet. I found this had a better characteristic that matched the need for advance particularly when restarting the motor at various temps. This compensation may also work with the coolant temp sensor but I found that to be more tricky. The second compensation table ( Comp 1 ) is run time vs RPM. The issue here is that I found that the engine wanted additional timing for almost 5 seconds after starting even when the engine was warm. A hot restart after just a few ( 1 - 10 ) seconds of the engine being shut-off may not need this comp but it didn't seem to hinder under this condition. The last thing was to put a hump in the base ignition table at RPM's below idle to prevent the RPM's from drooping once started and to promote a better initial accellaration of RPM’s from cranking speed to idle speed once the motor lights-off.

    Lastly, the base map has the stopped injection ( under fuel compensations ) set to 90. This allows you to inject extra fuel before starting the engine by stroking the throttle. With the adjustments above this should no longer be needed and strongly suggest that you set this to 0 to avoid the possibility of having extra unburned fuel hanging around in your intake manifold.

    Each engine combination may behave different so you may need to tweak these calibrations but it should definitly get you in the right direction. Nils recently made me a camshaft with more overlap compared to stock so I'll report back with any adjustments.

    Thanks again to Nils and Motec Pete for all your help !
    Attached Files Attached Files


  2. #2

    Join Date
    Feb 2008
    Location
    novwhere
    Posts
    597
    hi,

    why did you change your crank index from 301 to 460 ??? And cyl numbers why 4 in setup?
    Are you did change direct ??? Why?? All numbers from your curent map.

  3. #3
    It got WIFI and touchscreen ! PWCGUY's Avatar
    Join Date
    Jul 2009
    Posts
    216
    +1
    10
    Quote Originally Posted by repsol View Post
    hi,

    why did you change your crank index from 301 to 460 ??? And cyl numbers why 4 in setup?
    Are you did change direct ??? Why?? All numbers from your curent map.
    The crank index postion is 301 in the attached map. Not sure where 460 comes from ? The number of cylinders in Adjust > General setup > Main setup is 3 cylinders. Not sure where you see 4 cylinders ?

  4. #4

    Join Date
    Feb 2008
    Location
    novwhere
    Posts
    597
    Quote Originally Posted by PWCGUY View Post
    The crank index postion is 301 in the attached map. Not sure where 460 comes from ? The number of cylinders in Adjust > General setup > Main setup is 3 cylinders. Not sure where you see 4 cylinders ?
    hi,

    maybe I mistake - read from other map? sorry ?? I will check again

  5. #5

    Join Date
    Feb 2008
    Location
    novwhere
    Posts
    597
    Quote Originally Posted by PWCGUY View Post
    The crank index postion is 301 in the attached map. Not sure where 460 comes from ? The number of cylinders in Adjust > General setup > Main setup is 3 cylinders. Not sure where you see 4 cylinders ?
    hi,

    I was tiime to check and you're right, I mistake.
    Else how i can open txt file with i2?

  6. #6
    It got WIFI and touchscreen ! PWCGUY's Avatar
    Join Date
    Jul 2009
    Posts
    216
    +1
    10
    Hey for those interested I had replaced my stock 08 camshaft with a more agressive cam with more overlap. Based on some quick tuning yesterday I can definitly say that there are quit a few tweaks needed for idling and good low RPM throttle responce. For starters this cam definitly needs more advance at idle compared to a stock camshaft. Instead of 0 deg BTDC at 1700 RPM this cam needs almost +8 deg at 1800 RPM. I think this is why there was some debate about my earlier statement of needing 0 deg BTDC at idle ( which I stand behind for stock late model cams ) because some people have more agressive cams which clearly need more timing at idle.

    As soon as I get more information I will post.

  7. #7

    Join Date
    Feb 2008
    Location
    novwhere
    Posts
    597
    Quote Originally Posted by PWCGUY View Post
    Hey for those interested I had replaced my stock 08 camshaft with a more agressive cam with more overlap. Based on some quick tuning yesterday I can definitly say that there are quit a few tweaks needed for idling and good low RPM throttle responce. For starters this cam definitly needs more advance at idle compared to a stock camshaft. Instead of 0 deg BTDC at 1700 RPM this cam needs almost +8 deg at 1800 RPM. I think this is why there was some debate about my earlier statement of needing 0 deg BTDC at idle ( which I stand behind for stock late model cams ) because some people have more agressive cams which clearly need more timing at idle.

    As soon as I get more information I will post.
    I have 12/15 degrees at idle now with RR4224

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Replies: 44
    Last Post: 05-14-2016, 11:25 PM
  2. Replies: 0
    Last Post: 04-11-2013, 05:50 PM
  3. How to make your carbon seal water cooled
    By RXP rider in forum 4-Tec Performance
    Replies: 12
    Last Post: 03-29-2011, 08:27 PM
  4. How To Make Your Own T Handle Carb Screws
    By Cutlass in forum Yamaha How To & FAQs
    Replies: 5
    Last Post: 01-09-2011, 08:50 PM
  5. How to make your own rrfpr?
    By Thegaragejavea in forum 4-Tec Performance
    Replies: 2
    Last Post: 02-17-2009, 02:16 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •