it is time foe a technical thread--exhaust port heat
11-04-2012, 10:01 AM
#1
it is time foe a technical thread--exhaust port heat
Ok--please feel free to shoot all kinds of holes into these thoughts--i am not an expert--just trying to learn.
Exhaust port heat and its alleged affect on the side seals has been a topic of many discussions. For the sake of this thread lets assume that the side seals/springs are indeed affected by the hot temperatures in the exhaust port.
So what can be done to address that? Well, to the best of my knowledge, some tuners have injected gas into the chamber during lift throttle, rich a/f's, water methanol injection systems, advising people to not wrap/coat headers etc have been tried and suggested. Some of these measures have had questionable results, some have had slight results.
Well, I think I have one I haven't seen posted on this forum--or anywhere else.
Those that know me know that I have expressed my dislike for the aux air pump system. I understand why its needed, thats not the point.
Well, in looking at some old housings and a centerplate yesterday, I was noticing how little coolant flow is present around the exhaust port. Its not very much AT ALL.
Compared to the hot side ( i think the exhaust port should be thought of also as in the HOT side), it doesnt even have 10% of what the hot side has.
Why? Eureka! Its that damn aux air port. I never have really looked close at that area before.
I saw that the aux port sleeve took an area that could be used for a complete standard size coolant passage! that would increase the coolant flow around the exhaust port by at least 100%--if not more.
It would have to be professionally removed and sealed, but that could be down.
It would also mean that a different type of cat converter would have to be used by those that had to comply to emissions restrictions, but to some others that is not a problem.
Now my thoughts are if we can cool the exhaust port more then the side seals/springs may be less of an issue?
Discussion?
Flame suit on too
Exhaust port heat and its alleged affect on the side seals has been a topic of many discussions. For the sake of this thread lets assume that the side seals/springs are indeed affected by the hot temperatures in the exhaust port.
So what can be done to address that? Well, to the best of my knowledge, some tuners have injected gas into the chamber during lift throttle, rich a/f's, water methanol injection systems, advising people to not wrap/coat headers etc have been tried and suggested. Some of these measures have had questionable results, some have had slight results.
Well, I think I have one I haven't seen posted on this forum--or anywhere else.
Those that know me know that I have expressed my dislike for the aux air pump system. I understand why its needed, thats not the point.
Well, in looking at some old housings and a centerplate yesterday, I was noticing how little coolant flow is present around the exhaust port. Its not very much AT ALL.
Compared to the hot side ( i think the exhaust port should be thought of also as in the HOT side), it doesnt even have 10% of what the hot side has.
Why? Eureka! Its that damn aux air port. I never have really looked close at that area before.
I saw that the aux port sleeve took an area that could be used for a complete standard size coolant passage! that would increase the coolant flow around the exhaust port by at least 100%--if not more.
It would have to be professionally removed and sealed, but that could be down.
It would also mean that a different type of cat converter would have to be used by those that had to comply to emissions restrictions, but to some others that is not a problem.
Now my thoughts are if we can cool the exhaust port more then the side seals/springs may be less of an issue?
Discussion?
Flame suit on too
11-04-2012, 11:34 AM
#3
As much as I hate to say it ...this is another reason that the side ports are causing problems getting into the 400HP range with the Renesis motors. The heat and the 90 degree corner the exhaust has to go around are too much for the crappy cooling to take away
And we have all seen what is happening to the side seals from the heat...
Not sure whether or not it's viable to start modifying the housings in that area for the amount of gain it would bring though. it would take some serious TIG work and machining for an experiment that may or not help a lot.....
And we have all seen what is happening to the side seals from the heat...
Not sure whether or not it's viable to start modifying the housings in that area for the amount of gain it would bring though. it would take some serious TIG work and machining for an experiment that may or not help a lot.....
Otherwise I wouldn't have a clue what most of your abbreviations actually mean
11-04-2012, 01:29 PM
#6
What engines in what circumstances are having issues - which side seals , centre , outer or both ?
Last edited by Brettus; 11-04-2012 at 01:54 PM.
11-04-2012, 01:56 PM
#7
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I think he's refering to FI engines under high boost and/or engines with relatively lean AFRs.
11-04-2012, 02:17 PM
#8
From what I have seen...any 350+ HP engines that has been run hard loose side seals and fail in relatively short order...like 20K miles or so....and the only theory flying around seems to be from the heat of the exhaust gasses and the poor exit flow from the engine
11-04-2012, 04:03 PM
#9
Hit the name on the head dannobre. race engines also do not have a good life expectancy before loosing power.
Team--if you have heard of this before--please elaborate. Its new to me.
I dont think this area would be hard to fill in/seal?
Would it help? I wish I knew for sure.
Someone is going to try it...........I dont see how it could hurt.
It is just an idea for discussion.
Team--if you have heard of this before--please elaborate. Its new to me.
I dont think this area would be hard to fill in/seal?
Would it help? I wish I knew for sure.
Someone is going to try it...........I dont see how it could hurt.
It is just an idea for discussion.
11-05-2012, 07:50 AM
#11
i havent heard anymore about it? Since they are a builder/supplier one would think that if it was a big success then it would be promoted?
Concerning this cooling jacket modification-i dont how it could do anything but help. Pettit racing already does a modification of the cooling jacket between the lead and trailing sparkplugs--i actually have a seal ( like a water jacket seal--kinda)--between the sparkplugs on my engine. They do this to stop the hairline cracks that occur around the sparkplugs. It works.
Increasing coolant flow always results in more heat exchange--within reason of course.
For those of you that have access to irons and housings--look at this. Look at how little flow is being allowed around the exhaust port. The channels actually have a lot of restricter holes , for the lack of a better word. So the coolant has to stagnant at that point.
look at the difference: http://i175.photobucket.com/albums/w...s/DSCN0441.jpg
http://photos.motoiq.com/MotoIQ/Tech...jsn-009-X2.jpg.
Look at how much more coolant is avaiable around the PP engine exhaust side.
Keep in mind that the water flow within the irons themselves could also be affected. ( I think I can see the benefit of Evans coolant being in there rather than antifreeze mix). The coolant doesnt flow is a straight path--not by any means. I am sure there are ebbs and areas of stagnated flow within the irons?
Just thoughts. Yall know I do contemplate about things.
Concerning this cooling jacket modification-i dont how it could do anything but help. Pettit racing already does a modification of the cooling jacket between the lead and trailing sparkplugs--i actually have a seal ( like a water jacket seal--kinda)--between the sparkplugs on my engine. They do this to stop the hairline cracks that occur around the sparkplugs. It works.
Increasing coolant flow always results in more heat exchange--within reason of course.
For those of you that have access to irons and housings--look at this. Look at how little flow is being allowed around the exhaust port. The channels actually have a lot of restricter holes , for the lack of a better word. So the coolant has to stagnant at that point.
look at the difference: http://i175.photobucket.com/albums/w...s/DSCN0441.jpg
http://photos.motoiq.com/MotoIQ/Tech...jsn-009-X2.jpg.
Look at how much more coolant is avaiable around the PP engine exhaust side.
Keep in mind that the water flow within the irons themselves could also be affected. ( I think I can see the benefit of Evans coolant being in there rather than antifreeze mix). The coolant doesnt flow is a straight path--not by any means. I am sure there are ebbs and areas of stagnated flow within the irons?
Just thoughts. Yall know I do contemplate about things.
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