diff --git a/lib/autotune/index.js b/lib/autotune/index.js
index 5b165c919..1609ade0f 100644
--- a/lib/autotune/index.js
+++ b/lib/autotune/index.js
@@ -421,7 +421,7 @@ function tuneAllTheThings (inputs) {
         } //else { console.error("newCR",newCR,"is close enough to",pumpCarbRatio); }
     }
     // only adjust by 20%
-    var newCR = ( 0.8 * carbRatio ) + ( 0.2 * fullNewCR );
+    var newCR = ( 0.6 * carbRatio ) + ( 0.4 * fullNewCR );
     // safety cap newCR
     if (typeof(pumpCarbRatio) !== 'undefined') {
         if (newCR > maxCR) {
diff --git a/lib/determine-basal/determine-basal.js b/lib/determine-basal/determine-basal.js
index 034910024..368244a7b 100644
--- a/lib/determine-basal/determine-basal.js
+++ b/lib/determine-basal/determine-basal.js
@@ -617,11 +617,17 @@ var determine_basal = function determine_basal(glucose_status, currenttemp, iob_
             }
             UAMpredBG = UAMpredBGs[UAMpredBGs.length-1] + predBGI + Math.min(0, predDev) + predUCI;
             //console.error(predBGI, predCI, predUCI);
-            // truncate all BG predictions at 4 hours
-            if ( IOBpredBGs.length < 48) { IOBpredBGs.push(IOBpredBG); }
-            if ( COBpredBGs.length < 48) { COBpredBGs.push(COBpredBG); }
-            if ( UAMpredBGs.length < 48) { UAMpredBGs.push(UAMpredBG); }
-            if ( ZTpredBGs.length < 48) { ZTpredBGs.push(ZTpredBG); }
+            // truncate all BG predictions at lookahead_int hours in 5min segments
+
+	    if (typeof profile.lookahead_5mins === 'undefined') {
+		var lookahead_int = 48; }
+	    else if (profile.lookahead_5mins) {
+		var lookahead_int = Math.max(profile.lookahead_5mins, 27); }
+
+            if ( IOBpredBGs.length < lookahead_int) { IOBpredBGs.push(IOBpredBG); }
+            if ( COBpredBGs.length < lookahead_int) { COBpredBGs.push(COBpredBG); }
+            if ( UAMpredBGs.length < lookahead_int) { UAMpredBGs.push(UAMpredBG); }
+            if ( ZTpredBGs.length < lookahead_int) { ZTpredBGs.push(ZTpredBG); }
             // calculate minGuardBGs without a wait from COB, UAM, IOB predBGs
             if ( COBpredBG < minCOBGuardBG ) { minCOBGuardBG = round(COBpredBG); }
             if ( UAMpredBG < minUAMGuardBG ) { minUAMGuardBG = round(UAMpredBG); }
diff --git a/lib/profile/index.js b/lib/profile/index.js
index aafd80342..8aded3742 100644
--- a/lib/profile/index.js
+++ b/lib/profile/index.js
@@ -69,6 +69,7 @@ function defaults ( ) {
     // TODO: make maxRaw a preference here usable by oref0-raw in myopenaps-cgm-loop
     //, maxRaw: 200 // highest raw/noisy CGM value considered safe to use for looping
     , calc_glucose_noise: false
+    , lookahead_5mins: 48 // prediction truncation in hours x 12
   };
 }
 
@@ -92,6 +93,7 @@ function displayedDefaults () {
     profile.enableUAM = allDefaults.enableUAM;
     profile.curve = allDefaults.curve;
     profile.offline_hotspot = allDefaults.offline_hotspot;
+    profile.lookahead_5mins = allDefaults.lookahead_5mins;
 
     console.error(profile);
     return profile