Your Saab and IAT [Archive] - SaabCentral Forums

: Your Saab and IAT


megagooz
4th October 2010, 07:50 PM
hi.

lets say we're cruising and iat is at 100˚f

boost hard and iat jumps to 140˚

normal?

green machine
4th October 2010, 07:57 PM
Not sure of numbers but, yes. Thus the reason for all the talk of larger IC's plus the use of "misters" as the levels of tune go up;). It is all in an attempt to keep IAT's down.

megagooz
4th October 2010, 08:02 PM
hmm ok.

my friend's ms3 is the exactly opposite. his iat drops significantly under boost.

comtrang
4th October 2010, 08:59 PM
Can't really compare cars. Depends on the setup and everything.

What's your setup? It'll help to know that.

A recent log of mine of full 3rd and 4th gear pulls, temperatures started at 45c and ended at 93c. That was over a span of 20 seconds, though, so that's a long period but again it depends on what you're talking about. 3rd gear alone, temperature rises from 45c to 74c.

megagooz
4th October 2010, 10:04 PM
the exhaust mani on those is on the other side (take our engine turn it 180˚)

nothing unusual about my setup. stock intercooler

earlier was cruising at 26c, hard pull in third, 40c... outside temp 15c

comtrang
5th October 2010, 12:30 AM
Stock intercooler is the problem there. They heatsoak instantly, you can feel it.

megagooz
5th October 2010, 12:16 PM
ya... seems like a general flaw in design

megagooz
5th October 2010, 01:22 PM
anyone with aftermarket intercoolers want to chime in here? i'm curious how much of a difference there is

lowbudgethero
5th October 2010, 03:30 PM
When i went from new jersey to oklahoma the 100* + days made my car feel like original tune of 250-260 hp with 15psi boost at redline to about 3 seconds of full power to just under 10psi boost redline. The car felt like stock (200hp), have yet to get another intercooler due to money and lack of a garage now. Now that its getting into the 70-80s it's much better.

monza2t
5th October 2010, 03:54 PM
ya... seems like a general flaw in design

thats just how OEM type intercoolers are :roll:
the TMIC on my MINI was suuuuuuuper lame, it soaked before you could get out of 1st gear.

comtrang
5th October 2010, 08:12 PM
anyone with aftermarket intercoolers want to chime in here? i'm curious how much of a difference there is

My data is based on an aftermarket intercooler. If there's something in particular you're interested i.e. crusing, pulls in X gear, etc. let me know and I can share that information. I probably have hundreds of datalogs to go through.

The main solution here is really just to replace the intercooler with an aftermarket one. With my stage 3 setup before, I couldn't go through one gear without the intercooler getting heat soaked. I now spend hours at a time doing pull after pull while tuning and no issues other than that ~50* change on a continuous 3rd and 4th gear pull.

But again, post up what you're looking for and I can deliver.

megagooz
5th October 2010, 08:36 PM
My data is based on an aftermarket intercooler. If there's something in particular you're interested i.e. crusing, pulls in X gear, etc. let me know and I can share that information. I probably have hundreds of datalogs to go through.

The main solution here is really just to replace the intercooler with an aftermarket one. With my stage 3 setup before, I couldn't go through one gear without the intercooler getting heat soaked. I now spend hours at a time doing pull after pull while tuning and no issues other than that ~50* change on a continuous 3rd and 4th gear pull.

But again, post up what you're looking for and I can deliver.

cool. our cars are different but... cruise at 2,5k and pull to 6k and gimme before, after, and amb. temps. thanks dude!

others feel free to join the fun :) i'd like to hear from some viggens

GarrettCharger
5th October 2010, 09:00 PM
hmm ok.

my friend's ms3 is the exactly opposite. his iat drops significantly under boost.


WHHAAAAA??? Is your friend also injecting methanol or misting the outside of the IC with nitrous (an inexcusable waste of nitrous if you ask me)?? Even for isentropic compression (100% efficiency) the temperature will always increase with pressure. Decreasing IAT wile increasing boost is not thermodynamically possible unless you are doing something other than an IC to remove heat from the intake air.

Anyways, here are a few plots from one of my recent datalogs. The ambient temp was around 90 F during the datalog session. I have an aftermarket IC (21 x 9 x 2.75 from cxracing) so the temperature increase was much less than the 40 F increase you were observing.


http://i277.photobucket.com/albums/kk47/budleach/Engine-Vehiclespeed.jpg


http://i277.photobucket.com/albums/kk47/budleach/Enginespeed-pressure.jpg


http://i277.photobucket.com/albums/kk47/budleach/IAT-pressure.jpg

megagooz
5th October 2010, 09:30 PM
WHHAAAAA??? Is your friend also injecting methanol or misting the outside of the IC with nitrous (an inexcusable waste of nitrous if you ask me)?? Even for isentropic compression (100% efficiency) the temperature will always increase with pressure. Decreasing IAT wile increasing boost is not thermodynamically possible unless you are doing something other than an IC to remove heat from the intake air.

ooh graphs. maybe it has something to do with where the sensor is. our sensor is rite above the bpv, no? rite near the hottest part of the motor.... hmmm. i think it's measured in the intake mani on the ms3

megagooz
5th October 2010, 09:38 PM
oops. no he's not doing anything crazy like that. just a fmic

megagooz
5th October 2010, 10:11 PM
alright. 16c outside. 3rd gear (2,5k to 6k) - 24c to 48c

Cm452
6th October 2010, 01:50 AM
If I boost hard and long in 5th, lets say @ 3k rpm, IAT stays around 40C, if I do two hard pulls (2nd-3rd), it'll get up to 46ish. I have an after market intercooler, which is like 22X 8X 2.75-which does heat soak in the hot weather, but now that it is like 9 C outside it keeps temps low. I get murdered driving slowly and softly around with stop lights and such-IAT climb to 50-52c:(. BTW, I am pretty sure trionic systems limit boost below certain temperatures-if the intake is over 60c it cuts boost, no?
-Cm

GarrettCharger
6th October 2010, 01:52 AM
ooh graphs. maybe it has something to do with where the sensor is. our sensor is rite above the bpv, no? rite near the hottest part of the motor.... hmmm. i think it's measured in the intake mani on the ms3

The only way I could see sensor location having any effect is if the ms3 has an egr valve feeding the intake manifold (which our cars do not have). You say his IAT drops significantly under boost, what would the starting and ending IAT normally be when doing a high boost pull? and more importantry how do those two temps compare to ambient temp? If it were a 90 F day and the starting temp was something like 145 F with an ending temp of around 115 F, then I might buy that.

comtrang
6th October 2010, 02:46 AM
Green curve is temperature

http://img836.imageshack.us/img836/8003/lowboostfullrun.jpg

If I boost hard and long in 5th, lets say @ 3k rpm, IAT stays around 40C, if I do two hard pulls (2nd-3rd), it'll get up to 46ish. I have an after market intercooler, which is like 22X 8X 2.75-which does heat soak in the hot weather, but now that it is like 9 C outside it keeps temps low. I get murdered driving slowly and softly around with stop lights and such-IAT climb to 50-52c:(. BTW, I am pretty sure trionic systems limit boost below certain temperatures-if the intake is over 60c it cuts boost, no?
-Cm



That's not what you asked for megagooz, but I can still do that if you want. Starting at 2500rpm is pointless for me because there's only a couple psi available from there. Even where I started on that log, ~3200rpm, not much to speak of but you can get an idea of the temperatures.

Also side note on this run, timing not perfect up top so about 7psi was pulled during the 4th gear portion of the run. Don't believe the slow acceleration figures.

GarrettCharger
6th October 2010, 02:53 AM
If I boost hard and long in 5th, lets say @ 3k rpm, IAT stays around 40C, if I do two hard pulls (2nd-3rd), it'll get up to 46ish. I have an after market intercooler, which is like 22X 8X 2.75-which does heat soak in the hot weather, but now that it is like 9 C outside it keeps temps low. I get murdered driving slowly and softly around with stop lights and such-IAT climb to 50-52c:(. BTW, I am pretty sure trionic systems limit boost below certain temperatures-if the intake is over 60c it cuts boost, no?
-Cm

Trionic retards ignition for higher IATs, whenever ignition is being retarded from the base ignition map value (whether its due to high IAT or engine knock) the max airmass does get reduced.

comtrang
6th October 2010, 03:18 AM
Trionic retards ignition for higher IATs, whenever ignition is being retarded from the base ignition map value (whether its due to high IAT or engine knock) the max airmass does get reduced.

I haven't come across ignition reduction in logs, only from knock counts.





Quick second gear pull after leaving Starbucks, for you. Outside temperature ~65F.

http://img375.imageshack.us/img375/5695/2ndgearlogforiat.jpg

GarrettCharger
6th October 2010, 01:06 PM
The ignition timing will either advance if the IAT is cold, or retard if the IAT is hot. Either way it will be much less noticable than a knock pull which instantly pulls a certain amont of timing. The IAT-Ignition adjustment changes gradually with IAT and only changes the overall ignition timing by a max of a few degrees. But this will still affect the max airmass. (screenshot of T7 suite)


http://i277.photobucket.com/albums/kk47/budleach/IAT-ignition.png


Note: The vertical axis is in degrees btdc so, negative=retard, positive=advance. This value is then added to the base ignition timing value to get a corrected ignition timing value.

comtrang
6th October 2010, 01:49 PM
The ignition timing will either advance if the IAT is cold, or retard if the IAT is hot. Either way it will be much less noticable than a knock pull which instantly pulls a certain amont of timing. The IAT-Ignition adjustment changes gradually with IAT and only changes the overall ignition timing by a max of a few degrees. But this will still affect the max airmass. (screenshot of T7 suite)




Is this T7..? Not familiar with it.


EDIT - didn't read the whole post. T7suite it is. I don't think we've got these maps in T5suite, or at least I haven't seen them. Definitely haven't seen ignition pulled because of temperature.

GarrettCharger
6th October 2010, 03:18 PM
Is this T7..? Not familiar with it.


EDIT - didn't read the whole post. T7suite it is. I don't think we've got these maps in T5suite, or at least I haven't seen them. Definitely haven't seen ignition pulled because of temperature.

Ahh yes, I didn't realize you're a T5er. Lucky you. If I knew what I know now back when I bought my car I would have definitely gone T5... stronger motor AND simpler to tune... maybe next time around...I'm definitely curious to see the differences between T5 and T7 software. I imagine there would be quite a difference, with the T7 using a MAF sensor and electronic TB compared to the T5 setup of a manual TB and MAP-IAT based MAF calculations.

On another note, what are you running for engine internals Comtrang? I've heard the T5 internals are good for up to around 500hp.

megagooz
6th October 2010, 04:33 PM
...You say his IAT drops significantly under boost, what would the starting and ending IAT normally be when doing a high boost pull? and more importantry how do those two temps compare to ambient temp? If it were a 90 F day and the starting temp was something like 145 F with an ending temp of around 115 F, then I might buy that.

yes. for some reason he'd be at a higher temp at idle/cruise. and then under boost he'd drop to where i would be during idle/cruise. did that make sense?

i used to have a ms3. just thought it was interesting how it's the exactly opposite.

comtrang
6th October 2010, 04:52 PM
Ahh yes, I didn't realize you're a T5er. Lucky you. If I knew what I know now back when I bought my car I would have definitely gone T5... stronger motor AND simpler to tune... maybe next time around...I'm definitely curious to see the differences between T5 and T7 software. I imagine there would be quite a difference, with the T7 using a MAF sensor and electronic TB compared to the T5 setup of a manual TB and MAP-IAT based MAF calculations.

On another note, what are you running for engine internals Comtrang? I've heard the T5 internals are good for up to around 500hp.

Yep :) the only complaint I have is that T5 comes in the NG900 bodystyle.. which is why I'd love to have a '99.

Internals are 100% stock. Pretty much running a turbo bolted up to the original motor and all the supporting hardware to go with it. Then of course the tune.

Another member who doesn't frequent these forums as often has had 600+whp on stock internals including head gasket. No reason for things to break unless something was done incorrectly. In the future, I'd like to test that limit as well with a decent set of cams and springs to rev the same turbo up to 8.5k.

Cm452
7th October 2010, 12:42 AM
Is this T7..? Not familiar with it.


EDIT - didn't read the whole post. T7suite it is. I don't think we've got these maps in T5suite, or at least I haven't seen them. Definitely haven't seen ignition pulled because of temperature.
In the "boost" section, there is a map dedicated to limiting boost above and below certain temperatures. On my car I have it set to OEM, which is 0 C for the low limit and 60c for the high limit. On 100 degree days the thing pulls boost to around .7 bar, which you can also program.
T5 isn't stupid-works just as well as t7, it's just easier:cool: I have not seen ignition decrease maps for temp, but I have seen them for knock, which is a side effect of high IAT's.
-Cm