izzy Posted July 3, 2009 Share Posted July 3, 2009 I was just curious about how much can heat effect the performance of our cars. I went to the drag strip on wednesday after going stage 2 and my first run was a 14.1 at 95.6mph. This run was done after driving the cars for about 2 hrs and barely a 5minute cool down. They started calling the lanes as soon as I pulled up. I was upset because on the stage 1 cobb tune the car went 13.8 98 mph and I questioned the trap speed. I had a great launch ( 1.90 60ft ) and I did not miss any shifts. I did not get to run the car again after cooling down because we were rained out. Any input would be greatly appreciated. Link to comment Share on other sites More sharing options...
05lgt5spd Posted July 3, 2009 Share Posted July 3, 2009 Heat soak, the more heat under the hood, the more the top mount absorbs. I got a fmic, seems to make a large difference getting the IC out of the compartment. It was 90 here the other day my intake temp was 137 degrees. Link to comment Share on other sites More sharing options...
sschmelcke Posted July 3, 2009 Share Posted July 3, 2009 all i know is my car feels like a beast in 50 degree weather and like a honda civic in 90 degree weather. since ive gone FMIC is been better but heat sucks Link to comment Share on other sites More sharing options...
Spec B Posted July 3, 2009 Share Posted July 3, 2009 The ECU pulls about 4 degrees of timing when the IAT is above 122; that combined with the fact that hot air packs less O than cooler air, it is a pretty big difference. Link to comment Share on other sites More sharing options...
05lgt5spd Posted July 4, 2009 Share Posted July 4, 2009 Yeah I'm about to try to fab up an air box with ducting to fresh air. Would help alot I'm sure Link to comment Share on other sites More sharing options...
trademark Posted July 4, 2009 Share Posted July 4, 2009 Next time you go to drag on a hot day buy some dry ice from your local grocer and put a few pieces on the TMIC when you are in line to run.. it will really drop your temps.. I cant do this anymore since I went FMIC... :-( Link to comment Share on other sites More sharing options...
weitek Posted July 5, 2009 Share Posted July 5, 2009 The LGT seems to be more prone to heat soak than the STI from my experience. I've been helping Th3Franz log and tune his stage 2 LGT for a while and I've noticed it likes to pull timing during Auto-X runs and also just normal driving if it's really hot outside. I think the smaller tmic/scoop on the LGT contributes to that a lot. He is stepping up to an AVO tmic so I am really looking forward to that and hoping it will allow us to put in a little more timing and resist heat soak better. You probably don't want to mess with a fmic for a stage 2 car (not to say it couldn't help though). Link to comment Share on other sites More sharing options...
sschmelcke Posted July 5, 2009 Share Posted July 5, 2009 the front mount was one of the best investments i made. i think my perrin tmic was a complete waste of money. that thing heat soaked worse than the stocker Link to comment Share on other sites More sharing options...
henryq89 Posted July 5, 2009 Share Posted July 5, 2009 Fmic ftw! Link to comment Share on other sites More sharing options...
nm Posted July 5, 2009 Share Posted July 5, 2009 85F daythunderhill (probably 90 on the track)Hill to turn 94th gear @4-5kFoot to floorDid not accelerateMmmm, heat soak! I need an oil cooler and a TMIC (can't go FMIC for classing). Money for 100 octane would help too. Link to comment Share on other sites More sharing options...
weitek Posted July 5, 2009 Share Posted July 5, 2009 the front mount was one of the best investments i made. i think my perrin tmic was a complete waste of money. that thing heat soaked worse than the stocker Wow I really hope that is not the case with the AVO. Link to comment Share on other sites More sharing options...
Th3Franz Posted July 5, 2009 Share Posted July 5, 2009 If it is, I'll be going E85 sooner than planned -Franz The end of a Legacy http://www.youtube.com/th3franz Link to comment Share on other sites More sharing options...
mightyS Posted July 5, 2009 Share Posted July 5, 2009 My AVO TMIC was cool to the touch after 2 hours of street tuning at 91 degrees outside. I had my engine cover off since it wouldn't fit without trimming first. I hope more air flows through once I get the cover back on. Link to comment Share on other sites More sharing options...
nm Posted July 5, 2009 Share Posted July 5, 2009 If it is, I'll be going E85 sooner than planned You have nothing to worry about in Wisconsin. Link to comment Share on other sites More sharing options...
mwiener2 Posted July 6, 2009 Share Posted July 6, 2009 85F day thunderhill (probably 90 on the track) Hill to turn 9 4th gear @4-5k Foot to floor Did not accelerate Mmmm, heat soak! I need an oil cooler and a TMIC (can't go FMIC for classing). Money for 100 octane would help too. That's not heat soak if the engine had NO power. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
weitek Posted July 6, 2009 Share Posted July 6, 2009 You have nothing to worry about in Wisconsin. We still get in to the high 90's low 100's during the summer. Link to comment Share on other sites More sharing options...
nm Posted July 6, 2009 Share Posted July 6, 2009 We still get in to the high 90's low 100's during the summer. I lived in MN, I know what your weather is like. That's not heat soak if the engine had NO power. It had power. I was still going forward (it is an uphill section). The needle was inching forward. But it might as well not have been (1-2 mph ina straight). Link to comment Share on other sites More sharing options...
weitek Posted July 6, 2009 Share Posted July 6, 2009 It had power. I was still going forward (it is an uphill section). The needle was inching forward. But it might as well not have been (1-2 mph ina straight). ^^ Btw I noticed something when I was messing with Franz's map the other night. The stock LGT timing compensation starts to pull serious amounts of timing at as low as 90F air intake temp!! It's kinda crazy imo. We converted his map over to STI settings now.  LGT: [Table2D] Intake Temperature (Degrees F) -40 -22 -4 14 32 50 68 86 104 122 140 158 176 194 212 230 3.16 3.16 2.81 2.11 1.05 0.00 0.00 0.00 -2.11 -3.16 -3.87 -4.92 -5.98 -5.98 -5.98 -5.98 Ignition Timing Correction (Degrees) STI: [Table2D] Intake Temperature (Degrees F) -40 -22 -4 14 32 50 68 86 104 122 140 158 176 194 212 230 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 -0.70 -6.68 -8.09 -8.09 -8.09 -8.09 -8.09 Ignition Timing Correction (Degrees) Link to comment Share on other sites More sharing options...
mwiener2 Posted July 7, 2009 Share Posted July 7, 2009 it makes sense. the STi has a larger turbo and should have lower output temps with higher input temps than the LGT. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
weitek Posted July 7, 2009 Share Posted July 7, 2009 it makes sense. the STi has a larger turbo and should have lower output temps with higher input temps than the LGT. That's true to a point. If the turbo is within it's efficiency range it shouldn't generate any more heat than any other turbo, all other things being equal. Obviously the LGT has a smaller tmic but then I've been told it's more efficient than the STI tmic - although I don't really believe that anymore after what I've seen/experienced after trying to tune one.  Regardless, 90F still seems really low to me. With the stock intake that means it's going to see 90F IAT at around 85F ambient temp - maybe even lower. I mean I can understand why they did it, but it seems like really poor/lazy engineering if it can't handle ~85F without pulling timing. :\ Link to comment Share on other sites More sharing options...
mwiener2 Posted July 8, 2009 Share Posted July 8, 2009 it could also just be that ROM. I don't have a copy of mine handy to check. Subaru (all companies really) changes things across model years and even within models. They do a little R&D using us as the test subjects. They can cross reference warranty claims with minor changes and see if they had any effects....positive or negative. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
weitek Posted July 12, 2009 Share Posted July 12, 2009 Just updating with some data - Spec B's rom does the same thing. It also has some other very questionable timing compensations in terms of coolant temps, etc imo. Link to comment Share on other sites More sharing options...
nm Posted July 12, 2009 Share Posted July 12, 2009 Just updating with some data - Spec B's rom does the same thing. It also has some other very questionable timing compensations in terms of coolant temps, etc imo. Any idea what the accessport stock maps do? Link to comment Share on other sites More sharing options...
Cossey Posted July 12, 2009 Share Posted July 12, 2009 I believe there was an old reference around a few years ago w/ certain vehicles saying that for every 11*F the intake air temp at sea level is cooled/heated, the whp figure goes up/down 1%. this is not based on any timing, just pure air density and temperature. Link to comment Share on other sites More sharing options...
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