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Discussion Starter #1
Hi guys -- I am very curious what issues people on here are experiencing with their heatsoak, especially on "Dame Edna" (2006-2009) cars. I've posted on here in the past about how my car would bog down when it was warm, and as far as I know there's no definitive fix. Theories are high air intake temps, inadequate intercooler, electrical/grounding issues, fuel octane, and more.

What's so strange is that for the past couple summers I haven't had any problems. And I haven't changed anything. The only thing I did a couple years ago was take off the front bumper and clean off the radiator/intercooler/condenser fins with Coil Clean and rinsed the whole thing down. But honestly they didn't appear that dirty.

Today was super hot in the Twin Cities...nearly 100F and gross humidity. And yet the car ran like a top; no apparent "bogging" of any kind. It's so weird! Why is it such an intermittent issue for me? Anybody else have any updates on their heatsoak problems?

273830
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Mine hasn't been on the road for a week or two as I've finished up the rear end suspension work. And now that it's a thousand degrees out, the blower motor controller completely went kaput, so I'm waiting for that to arrive from esaab. Probably won't be back on the road until later this week.

However, prior to that, it was behaving poorly as the temps got above 85. On a recent trip to the junkyard I grabbed MAF, IAT, and intake pressure sensor. I swapped the MAF that day with no change in behavior, so either both suck or they're both fine. I'll try the other two over the next few weeks.

I wish I had access to better data logging capabilities.
 

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Fair point. Perhaps it will go back. Whether it's a good idea or not, it didn't really change the behavior, so either mine is similarly bad or they're both fine.
 

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I've posted about this before, but since converting to E85 almost a year ago, no heatsoak even out in the consistent 100 degree desert heat where I live. I struggled with the issue for years before and changed a bunch of parts with no improvement. Trionic was pulling tons of timing due to excessive knocking caused by high combustion chamber temps leading to improper combustion (despite always using 91 or 93 octane). E85 not only has much higher octane of about 105, but it also burns much cooler.
 

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but since converting to E85 almost a year ago, no heatsoak even out in the consistent 100 degree desert heat where I live.
There's probably a thread or two on this, but I'll ask in case there's not. What did you do to convert?
 

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The 2006-2009 models already have an E85-compatible fuel pump, so all you need is a flex-fuel tune that takes into account the % of ethanol after each fill-up (using the O2 sensor) and adjusts fuel/air mixture accordingly. I also opted to upgrade to bigger 630cc injectors putting me around 290 hp, the stock ones are only capable of around 230 hp on E85.
 

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No, it's a flex-fuel tune and will run on regular gasoline just fine. It calculates the mixture after each fill-up and adapts anywhere from E0 to E85 accordingly.
 

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The tune uses the O2 sensor to calculate the ethanol percentage. It's quite accurate in my experience.
 

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Discussion Starter #12
gb3347--very interesting. I think I've seen your other posts about running E85. Working theory: Maybe the "heat soak" (or lack of it) has to do with the ethanol level in regular fuels. Here in MN, fuels can be up to 15% ethanol. Maybe the ones that are on the higher end of that percentage reduce my bogging down issues, whereas ones with lower ethanol % make it bog more. I should throw in some non-oxygenated fuel (0% ethanol) in one tank and see if it bogs worse on a hot day. I've got some specific questions on your E85 tune: You said you only needed a tune and upgraded 630cc injectors? Was that all you had to do? Where did you source your tune and injectors?
 

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I've posted about this before, but since converting to E85 almost a year ago, no heatsoak even out in the consistent 100 degree desert heat where I live. I struggled with the issue for years before and changed a bunch of parts with no improvement. Trionic was pulling tons of timing due to excessive knocking caused by high combustion chamber temps leading to improper combustion (despite always using 91 or 93 octane). E85 not only has much higher octane of about 105, but it also burns much cooler.
Yep, I believe this came up in the original thread a year or two ago as well. The only drawback to E85 is the fact that you need 30% more volume to make the same HP, and spotty availability at the gas pumps. But the octane rating and charge cooling capacity is second to none. It’s also downright cheap compared to high octane race fuels. I know it’s not a Saab and a different animal, but my Camaro has 11.5:1 compression and I can still run full timing advance and 10 lbs boost (780 HP) on a hot summer day thanks to E85. That combo would be unheard of without it. I lose a solid 30+ WHP when I have to run 93.
 

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gb3347--very interesting. I think I've seen your other posts about running E85. Working theory: Maybe the "heat soak" (or lack of it) has to do with the ethanol level in regular fuels. Here in MN, fuels can be up to 15% ethanol. Maybe the ones that are on the higher end of that percentage reduce my bogging down issues, whereas ones with lower ethanol % make it bog more. I should throw in some non-oxygenated fuel (0% ethanol) in one tank and see if it bogs worse on a hot day. I've got some specific questions on your E85 tune: You said you only needed a tune and upgraded 630cc injectors? Was that all you had to do? Where did you source your tune and injectors?
That's my theory as well and would help explain why sometimes it ran better than others and why temp doesn't have a direct linear correlation to how the car runs. One day could be fine at 90F and later bog down at 80F.

Yep, that's it, you could even keep the stock injectors if you accept losing a few hp, you would still have a bit more torque than stock. It's been almost a year now with no adverse effects, I've noticed no cold-start issues (although our coldest weather is just above freezing, MN might be a different story). My mileage obviously went down to about 13-14 mpg city and 23-25 hwy but it's offset by the low price of E85. I sent my ECU in to Swede Fleet Tuning in CO and got the Siemens Deka 630cc injectors from Genuine Saab. Car makes about 290 hp and 350 ft-lbs torque, can do consistent pulls all day long no matter the temp, was totally worth it.

Another thing I've noticed is that my general engine bay temp used to be incredibly HOT for hours after shutting off the car on gasoline, now it feels much cooler and the heat dissipates way sooner.
 

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Yep, I believe this came up in the original thread a year or two ago as well. The only drawback to E85 is the fact that you need 30% more volume to make the same HP, and spotty availability at the gas pumps. But the octane rating and charge cooling capacity is second to none. It’s also downright cheap compared to high octane race fuels. I know it’s not a Saab and a different animal, but my Camaro has 11.5:1 compression and I can still run full timing advance and 10 lbs boost (780 HP) on a hot summer day thanks to E85. That combo would be unheard of without it. I lose a solid 30+ WHP when I have to run 93.
I dont mean to butt in but i always wondered how pump ethanol fuel was much better octane rating but yet it takes so much more of it to do the same thing ?
 

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I dont mean to butt in but i always wondered how pump ethanol fuel was much better octane rating but yet it takes so much more of it to do the same thing ?
E85 is much more resistant to knock and burns slower/cooler meaning less likelihood for uncontrolled combustion. It has about 30% lower energy content so you need more of it in order to make the same power, and mileage will of course suffer. But, as long as you have the necessary flow, it is much easier to make big power with a cool-burning high-octane fuel like E85.
 

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Discussion Starter #17
That's my theory as well and would help explain why sometimes it ran better than others and why temp doesn't have a direct linear correlation to how the car runs. One day could be fine at 90F and later bog down at 80F.

Yep, that's it, you could even keep the stock injectors if you accept losing a few hp, you would still have a bit more torque than stock. It's been almost a year now with no adverse effects, I've noticed no cold-start issues (although our coldest weather is just above freezing, MN might be a different story). My mileage obviously went down to about 13-14 mpg city and 23-25 hwy but it's offset by the low price of E85. I sent my ECU in to Swede Fleet Tuning in CO and got the Siemens Deka 630cc injectors from Genuine Saab. Car makes about 290 hp and 350 ft-lbs torque, can do consistent pulls all day long no matter the temp, was totally worth it.

Another thing I've noticed is that my general engine bay temp used to be incredibly HOT for hours after shutting off the car on gasoline, now it feels much cooler and the heat dissipates way sooner.
So just for giggles, since the 2006+ cars already have an E85 compatible fuel pump, would there be any harm in trying a little E85 without a tune? Would it blow up my engine?
 

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Discussion Starter #18
@gb3347 - one other question. Were the 630cc injectors plug and play or did they require any modification? (wiring or otherwise)
 

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You could try adding 2-3 gallons of E85 to a full tank to see if it makes a difference. Anything more and you might run too lean and get a CEL.

All that is needed for the injectors were fuel rail spacers so they don't go down too far into the manifold, I also got those from GS. Otherwise 100% plug-and-play.
 

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E85 is much more resistant to knock and burns slower/cooler meaning less likelihood for uncontrolled combustion. It has about 30% lower energy content so you need more of it in order to make the same power, and mileage will of course suffer. But, as long as you have the necessary flow, it is much easier to make big power with a cool-burning high-octane fuel like E85.
 
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