Question about detonation
#1
Scooby Regular
Thread Starter
Join Date: Nov 2004
Location: Leeds
Posts: 230
Likes: 0
Received 0 Likes
on
0 Posts
Question about detonation
Is detonation more likely to occur running high boost in hot weather or cold weather, my current boost was set mid summer. I know that the boost level drops a bit when the air temps are hot , is it safe to run the same boost when air temps are cold or do i need to knock it down a bit.
#2
Scooby Regular
iTrader: (1)
Join Date: Aug 2005
Location: Manchester ish
Posts: 18,547
Likes: 0
Received 0 Likes
on
0 Posts
when its cold, the air will be denser so it will contain more oxygen so the car will probably produce slightly more boost (more than likely just feel more lively). Whether or not you would need to adjust your boost levels is another matter but I would imagine the ecu would be able to cope with it.
Detonation is more likely to occur in hot weather running high boost, due to the air being less dense, therefore less oxygen to burn with the fuel
Detonation is more likely to occur in hot weather running high boost, due to the air being less dense, therefore less oxygen to burn with the fuel
#3
Scooby Regular
Thread Starter
Join Date: Nov 2004
Location: Leeds
Posts: 230
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by jaytc2003
when its cold, the air will be denser so it will contain more oxygen so the car will probably produce slightly more boost (more than likely just feel more lively). Whether or not you would need to adjust your boost levels is another matter but I would imagine the ecu would be able to cope with it.
Detonation is more likely to occur in hot weather running high boost, due to the air being less dense, therefore less oxygen to burn with the fuel
Detonation is more likely to occur in hot weather running high boost, due to the air being less dense, therefore less oxygen to burn with the fuel
#5
Former Sponsor
Join Date: Jul 2005
Location: Wellingborough, Northamptonshire
Posts: 2,859
Likes: 0
Received 0 Likes
on
0 Posts
both depending on how cold or how hot.
Cold air will be denser, and even at the same boost, you will have more air going into the engine, which means higher cylinder pressures and possibly increased det. However, if the car was limited by excessive temperatures in the past (say small TMIC and hig boost), and you cool the inlet charge you will more than like decrease det.
Paul
Cold air will be denser, and even at the same boost, you will have more air going into the engine, which means higher cylinder pressures and possibly increased det. However, if the car was limited by excessive temperatures in the past (say small TMIC and hig boost), and you cool the inlet charge you will more than like decrease det.
Paul
#6
To be precise, detonation is more likely in warm weather as the overall inlet charge temp is higher. There is a temp at which the fuel air mix with either fully or partly ignite in an uncontrolled manner during the combustion cycle.
Nothing to do with there being insufficient oxygen for the fuel. If anything just the opposite. Where there is too much oxygen for the fuel, ie an overly lean condition is where detonation is more likely to occur. Excess fuel will in most cases reduces the probability of det as it absorbs heat from the inlet charge, reducing the overall charge temp and hence the risk of det. Hence why turbo cars (Impreza included) are invariably mapped from the factory to run excessively rich on boost for safety.
The answer is still the same though. Hotter days more risk.
If concerned on det risks, fit a knocklink and if necessary reduce boost in warmer weather or increase fuel octane level with appropriate octane boosting products
Nothing to do with there being insufficient oxygen for the fuel. If anything just the opposite. Where there is too much oxygen for the fuel, ie an overly lean condition is where detonation is more likely to occur. Excess fuel will in most cases reduces the probability of det as it absorbs heat from the inlet charge, reducing the overall charge temp and hence the risk of det. Hence why turbo cars (Impreza included) are invariably mapped from the factory to run excessively rich on boost for safety.
The answer is still the same though. Hotter days more risk.
If concerned on det risks, fit a knocklink and if necessary reduce boost in warmer weather or increase fuel octane level with appropriate octane boosting products
Thread
Thread Starter
Forum
Replies
Last Post
Brzoza
Engine Management and ECU Remapping
1
02 October 2015 05:26 PM