I just had a utec installed on my evoviii. Other mods include HKS downpipe, hi-power exhaust, Random Tech cat., and Turbo XS BOV. I'm experiencing what feels like a "transition studder" when I start building boost, both with the Stage 1 map as well as a second map from my tuner. It's fairly noticeable. Tried changing plugs to make sure that wasn't the problem. I saw a link started on this earlier, but no further replies over the past few weeks. Any ideas or suggestions?

 

its normal. Post a log and ill point out where in transition it happens and give you a few ideas on how to minimize it. RRR

 

My solution was similar to another user's solution.. I took the 10% map and set it to ECU so it transitions to the next MLP smoother.. I also recommended earlier that the transition point be set to 30-33% instead of 25% so the studder is minimized in daily driving (you don't hit 30% or higher as often in regular driving)

 

Thanks guys. I'm new to all this. I'll post a log soon!

 

I agree with Jack,
I set the 10% column to ecu. THis lets the ecu do it's thing and pull down timing on tip in. this allows for very consistant transitions of 2-3 degrees timing change when moving into the 20% load site. transition is very smooth.

 

Here are a coupl eof examples of the transition:
3174,+24.1, 480, 49, 10, 00, +18.3, 18.0,ECU. , +0.0, 69.00, 462
3443,+24.1, 517, 50, 10, 00, +16.2, 23.0,ECU. , +0.0, 70.00, 618
3766,+23.9, 645, 50, 10, 00, +13.6, 30.0,ECU. , +0.0, 70.00, 809
4130,+23.9, 909, 50, 10, 00, +10.7, 40.0,ECU. , +0.0, 70.00, 856
4547,+23.7, 866, 49, 10, 00, +11.9, 45.0,ECU. , +0.0, 69.00, 992
4909,+23.9,1022, 49, 30, 00, +12.0, 49.0,+10.0, -2.2, 69.00, 943
5299,+23.9,1061, 49, 40, 00, +13.3, 50.0,+11.0, -4.2, 69.00, 972

Notice in the first one that the timing goes from +11.9 deg uder ecu control to +10 deg under utec control with a 49% throttle run.

3370,+24.1, 587, 55, 10, 00, +12.3, 23.0,ECU. , +0.0, 75.00, 586
3711,+24.1, 788, 66, 10, 00, +8.6, 34.0,ECU. , +0.0, 86.00, 712
4065,+24.1,1141, 84, 10, 00, +6.6, 44.0,ECU. , +0.0,100.00, 992
4474,+23.9,1228, 96, 20, 00, +5.8, 55.0, +9.0, -0.5,100.00,1269
4952,+23.9,1308,100, 40, 00, +8.4, 59.0,+10.0, -5.3,100.00,1282
5518,+23.9,1683,100, 60, 00, +10.3, 62.0,+12.0, -9.6,100.00,1412

And in the second that it goes from +6.6 deg under ecu control to +9.0 deg under utec control.

The mian thing I observed from all the data logging is the factory timing curve always dips on tip in then ramps up so if you can cath the transition near the bottom of the curve, so to speak, you will minimise tip in knock and have room to advance the curve as load increases.

 

Thanks for the help. I'll set my 10% map to ecu and see how it works. I posted a log as an attachment. Sorry for the length. I believe my transition point is 35%.

 

Just tried out the car with the new settings (10% ignition map set to ecu). Much better now. You guys are awesome!