Renesis seem to like the cold
12-09-2006, 09:51 PM
#1
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Renesis seem to like the cold
Now that winter is back my RX-8 seem to run stronger in the freezing weather then in summer. No test figures to support this but it dose seem to feel stronger. Anyone else experience this.
12-09-2006, 10:13 PM
#5
Colder air makes all engines run stronger.
Cold air compresses fuel into denser matter, thus allowing more fuel to be combusted in any given period.
This is the basic principle that causes supercharges and turbochargers to boost horsepower.
Cold air compresses fuel into denser matter, thus allowing more fuel to be combusted in any given period.
This is the basic principle that causes supercharges and turbochargers to boost horsepower.
12-09-2006, 10:44 PM
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Well, mine doesn't feel "better" in this cold, plus the mileage is worse (although improved from when I had those "issues"). I blame it on our current gas blend, which really sucks. 
Their attempt to help with winter pollution by putting all kinds of crap in our gas, causes our mileage to go down a ton, which causes us to use up a lot more gas, because it sucks, which wipes out the attempts at lowering winter pollution.
Their attempt to help with winter pollution by putting all kinds of crap in our gas, causes our mileage to go down a ton, which causes us to use up a lot more gas, because it sucks, which wipes out the attempts at lowering winter pollution.
12-10-2006, 11:19 AM
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I understand all this but have never noticed as much a difference in summer winter performance as with the RX-8.
Originally Posted by RotoRocket
Colder air makes all engines run stronger.
Cold air compresses fuel into denser matter, thus allowing more fuel to be combusted in any given period.
This is the basic principle that causes supercharges and turbochargers to boost horsepower.
Cold air compresses fuel into denser matter, thus allowing more fuel to be combusted in any given period.
This is the basic principle that causes supercharges and turbochargers to boost horsepower.
12-12-2006, 03:38 PM
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In the winter, the 8's tires tend to break away in most gears on dry but cold surfaces, adding to that butt dyno feel.
Much truth to cold air, my old turbo especially felt a bigger boost.
Much truth to cold air, my old turbo especially felt a bigger boost.
12-12-2006, 03:50 PM
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Yeah put a RB intake with the duct, then you really get some cold air into the engine. It's nice to put my hand on the intake and it is cold as ice during long run on a cold day. All that cold air going almost unrestriced into the Renesis, the car really does run well.
12-12-2006, 03:51 PM
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It is actually a number of issues that seems to give combustion engines "better" performance" in the winter. I'll try to explain in my simpleton way. Your engine temps probably run slightly cooler in the winter compared to summer. Internal engine heating far outweighs losses to ambient and so, while you may have a 50 degree difference (arbitrary number) between summer and winter ambient temperatures, your engine may only run a few degrees cooler (I am talking about internals) in the same comparison. Considering this and the fact that air entering in the winter is denser (Ideal Gas Law - gas is more dense as temperature decreases) than air entering during the summer, the car computer compensates for the air/fuel mixture and thus you get "more" expansion force during combustion of the fuel entering the engine.
In other words deltaPV=nRdeltaT (in this case, V and R are constants, n is near constant, T takes enginer temperature into account). Ambient heat losses can be taken into account, but would end up being too complicated to account for here. So, in colder ambient, delta T is larger and therefore so is delta. Delta P is the added "push" you feel in the cold temperatrues.
Although your engine may be running slightly cooler in the winter, the gain from air/fuel mixture is larger than the loss of running at lower engine temperatures (I may have confused myself here, I hope you are able to follow). This is a similar concept to the one cold-air intakes follow.
Again, this is a very "simpleton" understanding of the gains from cold ambient temperatures but it is all simple thermodynamic principles. I am sure some of the more experienced forum members can probably explain it better.
In other words deltaPV=nRdeltaT (in this case, V and R are constants, n is near constant, T takes enginer temperature into account). Ambient heat losses can be taken into account, but would end up being too complicated to account for here. So, in colder ambient, delta T is larger and therefore so is delta. Delta P is the added "push" you feel in the cold temperatrues.
Although your engine may be running slightly cooler in the winter, the gain from air/fuel mixture is larger than the loss of running at lower engine temperatures (I may have confused myself here, I hope you are able to follow). This is a similar concept to the one cold-air intakes follow.
Again, this is a very "simpleton" understanding of the gains from cold ambient temperatures but it is all simple thermodynamic principles. I am sure some of the more experienced forum members can probably explain it better.
12-12-2006, 05:32 PM
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You must have gotten all A's in school. In other words....our cars run really good in cold weather and a little better with the use of a CAI in any given temp.....Am I right? Also, correct me if I am wrong.....for every 10 degree drop in engine temp you could possibly gain 1hp.
Originally Posted by mabdeliz
It is actually a number of issues that seems to give combustion engines "better" performance" in the winter. I'll try to explain in my simpleton way. Your engine temps probably run slightly cooler in the winter compared to summer. Internal engine heating far outweighs losses to ambient and so, while you may have a 50 degree difference (arbitrary number) between summer and winter ambient temperatures, your engine may only run a few degrees cooler (I am talking about internals) in the same comparison. Considering this and the fact that air entering in the winter is denser (Ideal Gas Law - gas is more dense as temperature decreases) than air entering during the summer, the car computer compensates for the air/fuel mixture and thus you get "more" expansion force during combustion of the fuel entering the engine.
In other words deltaPV=nRdeltaT (in this case, V and R are constants, n is near constant, T takes enginer temperature into account). Ambient heat losses can be taken into account, but would end up being too complicated to account for here. So, in colder ambient, delta T is larger and therefore so is delta. Delta P is the added "push" you feel in the cold temperatrues.
Although your engine may be running slightly cooler in the winter, the gain from air/fuel mixture is larger than the loss of running at lower engine temperatures (I may have confused myself here, I hope you are able to follow). This is a similar concept to the one cold-air intakes follow.
Again, this is a very "simpleton" understanding of the gains from cold ambient temperatures but it is all simple thermodynamic principles. I am sure some of the more experienced forum members can probably explain it better.
In other words deltaPV=nRdeltaT (in this case, V and R are constants, n is near constant, T takes enginer temperature into account). Ambient heat losses can be taken into account, but would end up being too complicated to account for here. So, in colder ambient, delta T is larger and therefore so is delta. Delta P is the added "push" you feel in the cold temperatrues.
Although your engine may be running slightly cooler in the winter, the gain from air/fuel mixture is larger than the loss of running at lower engine temperatures (I may have confused myself here, I hope you are able to follow). This is a similar concept to the one cold-air intakes follow.
Again, this is a very "simpleton" understanding of the gains from cold ambient temperatures but it is all simple thermodynamic principles. I am sure some of the more experienced forum members can probably explain it better.
Last edited by 1stgen8; 12-12-2006 at 05:35 PM.
12-12-2006, 07:11 PM
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Originally Posted by 1stgen8
You must have gotten all A's in school. In other words....our cars run really good in cold weather and a little better with the use of a CAI in any given temp.....Am I right? Also, correct me if I am wrong.....for every 10 degree drop in engine temp you could possibly gain 1hp.
. 1 hp/10 deg drop may be a good rule of thumb, although there are certainly many other factors that are not being considered when using IGL. The IGL is just an oversimplified explanation for the increased performance in cold weather, however it is not an accurate quantitative method for determining gains. There are certainly many other factors not considered (engine heat losses to ambient, expansion, etc., etc.). The increase in performance should not be limited to only our rotary engines, but engines in general. Again, this is what CAI are trying to achieve, although I would think these are more "sensitive" to ambient conditions.
12-12-2006, 07:16 PM
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I think the renesis likes the cold air. Of course the lower intake air temp. a cooler running engine might play a more important role than you might think... we have a hot burning rotary engine afterall, that is why we have the MAZSPORT FAN MOD. they wouldnt sell something if its useless 
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Last edited by Renesis_8; 09-11-2011 at 10:57 AM.
12-13-2006, 02:56 PM
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Originally Posted by Renesis_8
I think the renesis likes the cold air. Of course the lower intake air temp. a cooler running engine might play a more important role than you might think... we have a hot burning rotary engine afterall, that is why we have the MAZSPORT FAN MOD. they wouldnt sell something if its useless
12-13-2006, 11:40 PM
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The difference for me between a 70 degree non-humid day and an 85 degree humid day is like night and day.
I hate the car on hot days because it doesn't have enough power to hardly get going without 4k+ rpms when letting the clutch out.
On the 70 degree days, like we're finally having a lot of... the car is a blast and has plenty of power.
I brought this up on another thread and had a "MazSport Cooling Mod" suggested to me, which I'm definitely going to look into it for hot days.
I hate the car on hot days because it doesn't have enough power to hardly get going without 4k+ rpms when letting the clutch out.
On the 70 degree days, like we're finally having a lot of... the car is a blast and has plenty of power.
I brought this up on another thread and had a "MazSport Cooling Mod" suggested to me, which I'm definitely going to look into it for hot days.
12-13-2006, 11:43 PM
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Originally Posted by csuttman
The difference for me between a 70 degree non-humid day and an 85 degree humid day is like night and day.
I hate the car on hot days because it doesn't have enough power to hardly get going without 4k+ rpms when letting the clutch out.
On the 70 degree days, like we're finally having a lot of... the car is a blast and has plenty of power.
I brought this up on another thread and had a "MazSport Cooling Mod" suggested to me, which I'm definitely going to look into it for hot days.
I hate the car on hot days because it doesn't have enough power to hardly get going without 4k+ rpms when letting the clutch out.
On the 70 degree days, like we're finally having a lot of... the car is a blast and has plenty of power.
I brought this up on another thread and had a "MazSport Cooling Mod" suggested to me, which I'm definitely going to look into it for hot days.
I weep for your clutch
12-13-2006, 11:45 PM
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How much does humidity factor into the equation?
I live in S. Florida and it's really humid here probably 80% of the year. It hasn't been good for my 8!
I live in S. Florida and it's really humid here probably 80% of the year. It hasn't been good for my 8!
12-13-2006, 11:47 PM
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Originally Posted by Xantium
I weep for your clutch