Pyrometers
#1
Registered
Thread Starter
Join Date: Oct 2000
Location: Fells Point MD
Posts: 532
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
I am debating adding Pyrometers to my carb HP500s. I am thinking of making an aluminum plate to go betweet the Gil manifolds and the tailpipes and put the sensors there. I know in an ideal world, the sensors would be as close to the exhaust port as possible, but I think this might work and be relatively simple.
What should the temps read at that spot and is aluminum ok, or should I use stainless steel?
What does an O2 sensor determine? Does it have value on motor with 500HP?
Thanks
Shawn
What should the temps read at that spot and is aluminum ok, or should I use stainless steel?
What does an O2 sensor determine? Does it have value on motor with 500HP?
Thanks
Shawn
#2
Registered
![Default](/forums/images/icons/icon1.gif)
Shawn
I would not use aluminum steel or stainless the temps should not exceed 1400 degrees that carb set up is pretty good from the factory I tell you from experience when we ran the factory boats we tried everything and I found the stock set up to make the best power.Sincerely Laz Mesa
I would not use aluminum steel or stainless the temps should not exceed 1400 degrees that carb set up is pretty good from the factory I tell you from experience when we ran the factory boats we tried everything and I found the stock set up to make the best power.Sincerely Laz Mesa
#3
Registered
Thread Starter
Join Date: Oct 2000
Location: Fells Point MD
Posts: 532
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
Laz, thanks for your help. You are recommending that I use stainless steel, right? My motors have been rebuilt and the carbs changed by Nickerson in Philadelphia, with a little head work and a new cam. I would expect the exhaust to cool a little as it travels through the water jacketed manifold, so if I stay at or under 1400 degress, I will not run lean, correct.
thanks
shawn
thanks
shawn
#4
Platinum Member
![](https://www.offshoreonly.com/forums/images/icons/platinum_member_star.gif)
![Default](/forums/images/icons/icon1.gif)
Shawn,don't buy gaffrig egts if you are considering them,mine read 200-250 degrees hot. be careful if you mt them too far from ideal location,for example,if they were showing 1300 between tailpipes and exhaust and discharge temp was 1500 leaving block but you didn't know it you could be thinking you were safe when really you were lean,just my .02,Smitty
#5
Registered
Join Date: Nov 2002
Location: Bonita Springs, Florida
Posts: 3,029
Likes: 0
Received 1 Like
on
1 Post
![Default](/forums/images/icons/icon1.gif)
Originally Posted by articfriends
showing 1300 between tailpipes and exhaust and discharge temp was 1500 leaving block but you didn't know it you could be thinking you were safe when really you were lean,just my .02,Smitty
Artic is calling that one right on the mark. Positioning of the thermocouple is everything. I have EGT's (Exhaust Gas Temperature) on my plane. It is a great tool to determine exact lean setting and conserve fuel when running at a constant speed. Touch those throttles and the % of air and fuel changes immediately. If you increase the demand and do not change the mixture you will have a melt down.
Barometric pressure, ambient air temperature and altitude greatly effect the EGT setting. There is no single ideal setting. It would be different everyday.
Last edited by expresscat39; 10-16-2004 at 06:51 AM.
#6
Registered
Thread Starter
Join Date: Oct 2000
Location: Fells Point MD
Posts: 532
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
Articfriends, thanks, I intended to use the gaffrig parts. Whose do you recommend? I thought the temps should be around 1350 at the exhaust port, so how much should they cool off by the time they get to the tailpipe? 100-200 degrees? Hope someone has done this before, or can do the math, cuz I sure don't know how.
Express, thanks, I don't expect to change every weekend, but would like to be able to check the set up until I get it right and then just let her run a little bit fat.
thanks
Shawn
Express, thanks, I don't expect to change every weekend, but would like to be able to check the set up until I get it right and then just let her run a little bit fat.
thanks
Shawn
#7
![Default](/forums/images/icons/icon1.gif)
I just set my CMI's to the factory to have an O2 sensor bung welded into the collector elbow on top and an EGT bung welded on the headpipe just after the flange and before the cool collar. I want to see them both together.
#8
Registered
Join Date: Nov 2002
Location: Bonita Springs, Florida
Posts: 3,029
Likes: 0
Received 1 Like
on
1 Post
![Default](/forums/images/icons/icon1.gif)
1350/1400 max. Do not know tailpipe temp.
In regards to your setting, if you set @ sea level(a standard pressure of 29.92) and have a low pressure or cold front passes through you will be running leaner. If you set at 80 degrees F. and it gets down to 60 you will be running extra lean. If both happen at one time?
Make sure you set it on the FAT side. When you are running WOT and your engines are louder than usual pull back, you are too lean.
In regards to your setting, if you set @ sea level(a standard pressure of 29.92) and have a low pressure or cold front passes through you will be running leaner. If you set at 80 degrees F. and it gets down to 60 you will be running extra lean. If both happen at one time?
Make sure you set it on the FAT side. When you are running WOT and your engines are louder than usual pull back, you are too lean.
#9
Registered
Join Date: Feb 2004
Location: Murray,KY
Posts: 487
Likes: 0
Received 0 Likes
on
0 Posts
![Default](/forums/images/icons/icon1.gif)
Probably better to trust an O2 sensor for rich or lean. Look(search) for other threads on this subject and "EGT". To many variables and recommended heat ranges to tune just using this esp. since you are averaging your cyl way out there and most likely #2 and #7 are hotter.
#10
Platinum Member
![](https://www.offshoreonly.com/forums/images/icons/platinum_member_star.gif)
![Default](/forums/images/icons/icon1.gif)
Shawn,i don't know who's gauges to buy,what i do know is when i ordered my lightning headers i payed extra to have exhaust probe holes built near the flanges on #7,put gaffrig probes and gauges on boat along with the headers,took boat out(this was 4 years ago) and egts pegged past 1500deg mark to what would be about 1600,turned up fuel press,made another pass,boat seemed rich and sluggish,still showed about 1500 and plugs were blackish brown. Sent ecm in and had it reprogrammed based on temp showing,re-installed it,boat was a real turd,plugs were almost wet,temp was still about 1400. At this point i called tyler crockett marine,told him what i had going on,he said those egt gauges and probes were always off(i thought they were the best you could get) and NOT TO TRUST THEM. I had him RE-reprogram my ecm,boat ran OUTSTANDING,gauges were always past 1450-1500 but motor didn't melt down,plugs colored good. I conducted a "home test" of my egt probes using a soft flame going thru a 10" piece of conduit on the end of a jiffy torch (it was the only way to get temp down of flame). Holding the same flame on each probe individually one read 1175,the other 1150,i also pulled the probes on my snowmobile i race and the pyro 2000 brand egt's read around 950 with same flame,so i came to my conclusion of the 250 degree innaccuracie from that,Smitty
Last edited by articfriends; 10-16-2004 at 03:23 PM.