is the cool weather that affective?

[NOAHSR10]

i have the t-28 killer installed in my car and it has been giving me various results. In the mornings its probably about 60~65 degrees outsidei start my car for 3 minutes before school in the morning get into it, and start driving. As i pull out onto the main road and rip it (to rival to all the people at the bus stop) the turbo spools up to about 17 at about 2500 rpm and pulls extremellllly hard all through the gears (scaring? the crap out of the girl i drive to school)

Ok now its about 3:00 after school about 75 degrees outside and im on my way home in slow trafic. I turn onto the main road and again let her open. same spool up, same psi, but the thing just feels like it runs out of power. The turbo feels totally different at 17 psi, so noticable that the girl i drove in the morning even noticed it.

I know how the cold weather (dense, cold air) does play a factor in performance. But i do not think that drastically. Am i experiencing heatsoak? Is the stock SMIC not doin it enough? Or would switching over to BPR7ES with a colder rating help me out. Thanks for any help...

 

[Kingdom]

having a big intercooler and colder plugs will certianly make it run better in the heat but it will go even faster in the cold.

You cant help it, if its turbo and its cold its gonna be fast.

 

[Defiant]

Originally posted by Kingdom
having a big intercooler and colder plugs will certianly make it run better in the heat but it will go even faster in the cold.

Um... no. Plug "temps" have to do with after the burning, not what the weather's like.

It's probably your head. Not the car's, but your mindset. Even motorcycles feel slow after a month. That ten degrees temp change won't matter to your car.

 

[Wobble]

.. unless your intercooler is VERY inefficiant i.e. stock, that thing can get heat soaked quick... even by a T28

 

[Enigma_Man]

I'm not as familiar with 2g's, but maybe you're running so close to the edge of knock, that the few extra degrees push you over that line, and your car pulls timing, and feels like a civic Ten degrees of outside air difference shouldn't make _that_ much of a power difference.

For someone more familiar with 2g's, is 17 psi too much to run w/o a safc or injectors? He's got a 190 lph fuel pump according to his mods.

Noah, your car might end up actually being a little faster (and healthier) if you turn down the boost a few psi, give that a shot, and see if the power levels are more stable.

-Jesse

 

[QuickerDSM]

Originally posted by Defiant

It's probably your head. Not the car's, but your mindset. Even motorcycles feel slow after a month. That ten degrees temp change won't matter to your car.

I have to REALLY dis-agree with this comment. I too notice a HUGE difference in the mornings. Lately it's been about 55deg in the mornings, and the car pulls sooooo much harder. It's not just "in our head" dude.

I also tend to agree with Wobbles comment about the intercooler efficiency. I'm still using the stock sidemount so that might be a large contributing factor. When it's really hot out (90+deg) the stock intercooler gets heat soaked by the top of 2nd gear, and I get some knock/timing retard during 3rd gear.

Mike

 

[13secGST]

yeh...it sounds exactly like what Enigma_Man is saying. To me anyway, you are running so much psi and don't have the fuel mods to support it, so when the temp outside goes up, your intake temps go up even a little higher and cause the car to knock more and pull timing.

I was having a similar problem with my big16g when all I had was a 255lph and running 17psi...then I turned it down to 14 and the car actually pulled harder because I gained 5 degrees of timing across the board. which more than made up for the decrese in boost.

Turn down the boost until you have injectors/logging tool/and tunning tool. And I would suggest DSMLink as the logging/tunning tool.

 

[Wilsonman02]

10 degree's shouldnt make a huge difference, but in the mornings its cooler and less humid, at least hear, and i know both my cars run better. Same thing happens late at night, if i drive on a cool night, the car just pulls a little hard. Every little bit helps i guess.

 

[Enigma_Man]

Yeah, I'm not saying that there won't be some difference either. I love the cool night/morning air, and I definitely notice some increase, but from the description of it running out of power, it sounds like knock timing retard.

-Jesse

 

[NOAHSR10]

i was wondering about temperature and heat soak because it pulls hard during the first few miles of driving, then it starts to die off. if it was pulling timing, is that reset every time the car is turned off? then does the ecu adjust afterwords, is that why i could be getting the dying off effect after the timing is adjusted? thanx...

 

[Nomad666]

Same thing happened to me eccept it wasn't the temp that effected me it was the gas that I used. In the morning I droped off this girl at school. On the way I ripped it a couple of times(not to show off or anything) after I dropped her off I noticed that my tank was empty and the closest gas station only had 91 octane gas. I had to fill her up with that(I always put 94octane) after getting out of the gas station I ripped it again, the car felt noticebly slower. The moral of the story, knock is back, and more than likely that is your problem.

 

[Enigma_Man]

Originally posted by NOAHSR10
i was wondering about temperature and heat soak because it pulls hard during the first few miles of driving, then it starts to die off. if it was pulling timing, is that reset every time the car is turned off? then does the ecu adjust afterwords, is that why i could be getting the dying off effect after the timing is adjusted? thanx...

When it pulls timing due to knock, it gives you back the timing as soon as the knock goes away (pretty much).

It probably pulls hard during the first few minutes, because the engine is still relatively cool, but then the whole engine bay warms up to operating temperature, and you start to get heat-induced knock. All I can say is just to repeat to turn it down a psi or two, and see if it's more consistent. You won't have as much power when it's chilly, but you won't get timing retard or knock (which can seriously damage your engine) if you ease up a little bit. I know it's a difficult thing to remove power but just give it a shot, and see if that helps.

-Jesse

 

[Kevin Jewer]

For me, on a well modded car, I can see as much as 3 lbs/min difference in airflow at the same boost, betwen the warm day and a cool night. Thats a good 20 hp. And you can feel it. Its partly because the intake air itself is denser, and partly because the IC is more efficient with cooler ambient air. With a shite sidemount, this is even more apparent. Log your airflow in both cases, and you may find the reason your car is faster when its cold. This isnt even taking timing into cosideration, but that will also be a factor, expecially on setups where the turbo and I are at thier limts already and the high temps give it a tendency to knock. In my case, timing doesnt change (Large FMIC), its all from ariflow.

 

[91TalonTSiCT]

Cooler air=denser air. denser air=more O2 molecules/cu. cm. More O2 means more fuel. Thats why it feels like its pulling harder.

 

[NOAHSR10]

update: i lowered the boost down to 14... yes the car does feel slower but its running alot smoother (less speratic). i still feel the difference when its under the same cold conditions, but i guess thats just cold air for you. im planning on getting some bigger injectors, safc, and datalogger asap, but need to save up for each. ill probably start out wit the datalogger?

 

[jdmawd]

Cold air makes a huge difference nuff said. if you have nothing to compare your oven baked under hood intake on obviously you wont agree. A simple intake temp gauge and pocket logger will answer all your question on this subject.

 

[NOAHSR10]

ok got the pocketlogger, at WOT my timing is 4 degrees... is that not good?

 

[nowayout]

Originally posted by NOAHSR10
ok got the pocketlogger, at WOT my timing is 4 degrees... is that not good?

4 degree is bad
here my log
Time RPM Knock Timing O2 Inj P/W
00:30.7 3812 0 30 0.82 6.923
00:30.9 3875 0 29 0.82 7.436
00:31.0 3906 0 28 0.82 7.949
00:31.2 4000 0 27 0.82 9.231
00:31.4 4062 0 26 0.84 10.256
00:31.5 4125 0 26 0.86 11.026
00:31.7 4219 0 24 0.86 12.308
00:31.8 4312 10 19 0.86 13.846
00:32.0 4375 10 19 0.88 13.846
00:32.1 4438 10 19 0.88 14.103
00:32.3 4531 9 20 0.88 14.359
00:32.4 4625 9 18 0.88 14.615
00:32.6 4688 9 18 0.88 14.615
00:32.7 4750 9 18 0.88 14.872
00:32.8 4844 8 19 0.88 14.872
00:32.9 4969 8 19 0.88 15.128
00:33.1 5000 8 19 0.88 15.385
00:33.2 5062 8 19 0.88 15.385
00:33.3 5094 8 20 0.88 15.385
00:33.5 5219 7 20 0.88 15.641
00:33.6 5281 7 19 0.88 15.641
00:33.7 5312 8 20 0.88 15.897
00:33.9 5438 8 20 0.88 15.897
00:34.0 5469 8 20 0.88 15.897
00:34.1 5531 7 21 0.88 16.154
00:34.2 5625 7 21 0.88 16.154
00:34.3 5656 7 21 0.88 16.41
00:34.4 5750 7 21 0.88 16.667
00:34.5 5750 7 21 0.88 16.923
00:34.6 5812 6 22 0.88 16.667
00:34.7 5906 6 23 0.88 16.667
00:34.8 5938 6 23 0.88 16.923
00:35.0 6031 6 23 0.88 17.179
00:35.1 6031 6 23 0.86 17.179
00:35.2 6031 6 22 0.86 17.179
00:35.3 6125 5 22 0.86 17.179
00:35.4 6156 5 21 0.86 17.179
00:35.5 6281 5 21 0.86 16.923
00:35.6 6281 5 20 0.88 17.179
00:35.7 6375 5 19 0.86 16.923
00:35.9 6469 4 20 0.86 17.179
00:36.0 6469 4 20 0.86 16.923
00:36.1 6562 4 20 0.86 16.923
00:36.2 6500 4 20 0.86 16.923
00:36.3 6562 5 19 0.86 13.333
00:36.4 6594 4 18 0.86 16.667
00:36.6 6719 4 18 0.86 16.41
00:36.7 6719 4 18 0.86 16.41
00:36.8 6875 4 18 0.86 16.41
00:36.9 6812 4 18 0.86 16.154
00:37.0 6906 3 18 0.86 16.154
00:37.2 6938 3 18 0.86 16.154
00:37.3 6969 3 18 0.86 15.897
00:37.4 6969 3 17 0.86 15.897
00:37.5 7094 3 17 0.86 15.897
00:37.6 7156 2 18 0.86 15.641
00:37.8 7125 2 17 0.86 8.462

 

[13secGST]

ok 1gs are completly different with timing than 2gs and should not even be compared

4 degrees...where are you getting 4 degrees...do a WOT pull in 3rd gear...start out at about 2500rpms floor it till redline or 7500 then check the datalog. Your timing will most likely drop from 3-3.5 and then start to rise. If your lowest timing is 4 degrees and it goes up after that...then you are good. If 4 degrees is your highest, than that is horrible...I was getting about 13 degrees @7000 of timing with stock injectors and Big16 @ 14psi and dropped to 3 degrees somewhere in the 3-3.5 range

Now with DSMLink my timing drops to about 1degree most of the time and advances to 18-19 degrees by 7500...so it is better and that is with 0-1 counts of knock throughout the powerband.

And nowayout...don't know if it is just the 1g differnce but isn't timing supposed to advance not stay linear and drop? and also...don't know if its just a 1g thing but those O2 volts seem WAY low and unsafe...I know the lowest us 2g guys like is .92 and that is low mine vary between .94-.96 and those create EGTs around 1550-1600 F

 

[13secGST]

NOAHSR10...pm me if you have some tunning questions...I have some experience and understand the stuff...I should now that I have DSMLink.

 

[nowayout]

My O2 has alwasy been around .88 and .86. Any thing higher and you start seeing black smoke out the back from being too rich. I don't depend on O2 voltage very much . I use Mustly timeing, inje3ctor P/W and knock. If I'm running out of injector and my O2 is low then I know I'm in the danger zone. It's looks like I at 85% duty on the run. I'm on the edge at this piont. But it's with 43 psi of Fuel pressure and i will change to 53 psi and do another run when time permits. 2g O2 have alway been higher than 1G's.

 

[marksae]

The ECU gives you an extra degree of timing advance if your MAF air intake temperatures are below 84F. You also get another degree of timing if your water temps are below 206F. 2 degrees of timing + cooler weather can make a very noticeable seat of the pants difference.

 

[Groomz]

Difference between driving in 110F Texas heat w/ the A/C on and the A/C off on a morning run at 60F is a hell of alot ( butt-dyno only ). The ECU cuts boost via the BCS and timing when it gets hot like that, so the ECU definitely will give you uncut boost and full timing when its cold. Thats what my car does at least.

 

[Kevin Jewer]

Timing should drop to 10ish when full boost hits and rise to high teens or whatever you get. Dropping to 1-3 sounds bad to me. While its true that the ECU pulls one degree of timing over 84f, its also import to note that it also pulls a degree out below 35 or so. O2 voltage is just as useless as EGT, (search this site for "egt" and my user name for a lengthy post on the subject) especially when comparing the numbers from car to car.

Now in my case, with the MAF translator, my intake temps are always reported as 80 degrees. So I dont get any more timing from getting below 84. But you still get the advantages of denser air, and more efficient IC. This is much more important though on cars with SMICs than cars with FMICs. Same goes for cars that are running thier turbos les efficiently.

 

[irn__man]

Originally posted by NOAHSR10
i was wondering about temperature and heat soak because it pulls hard during the first few miles of driving, then it starts to die off. if it was pulling timing, is that reset every time the car is turned off? then does the ecu adjust afterwords, is that why i could be getting the dying off effect after the timing is adjusted? thanx...

Note:

On 2G DSM's when your intake temp is above 84 Deg F, you will lose 1 degree of timing. The same holds true if the Intake Temp is below is below 34 deg F. Also, if your coolant temp is below 206 deg F you will get full timing. If it goes above 206 deg F, you will lose one degree and if it goes above 224 Deg F you will lose two degrees of timing.

All, this is verified threw DSMLink.

fwm