Just planning to mount some exhaust gas temperature probes so I am able to monitor the effects of playing with Water Meth Injection. Ive been reading up on the net and it seems the general idea is to mount them in the manifold before the turbos. You select the cylinder that tends to run hottest, and fit the probe in the manifold before the exhaust gases merge from other cylinders. This is the most accurate method used to tune by. Im wondering, since i wont be using this data to tune, rather to see the differences of using the WMI gear- could I mount it in a simpler spot? I wont be pulling the engine apart to mount it. Im hoping to just buy the probe and take the car to an exhaust shop get them to weld it in for a few dollars. While it will be slightly less accurate, is it ok to weld the probe in after the dump pipes, before the cats? Or is this too late down the exhaust and will be useless? I pretty much want to get a read-out standard with intercoolers, fit the WMI injection coupled with intercoolers get a read-out, remove intercoolers and run pure WMI and compare the differences. If it all goes well later down the track I guess I would take it in to get tuned and I guess tune it till the lowered WMI EGT reading is similar to the original (plan is to allow for a more aggressive tune that will keep combustion temps similar thus adding more power without more risk of knock). So firstly, will it be ok to fit the probe after dumps, before cats? Or is it recommended to put them in the dumps near the 02 sensors? Or is it totally necessary to fit into the manifold directly (big job fitting it). Secondly, is one probe on one side ok or will I definately need one on either side, and thus two guages/ digital displays in the car?
Well if it was for tuning you have only the option of putting it in the runner of cylinder 6 and 5 for a reading that has any merit. Followed by placing it just before the turbo on the collector. Once the exhaust hits the exhaust wheel and expands your going to be getting readings which are essentially useless for any real comprehension on combustion temps. Regarding placement on one bank or both, again, not the best for tuning, because you tune to your weakest aspect. If the passenger bank is running hotter for whatever reason, and your EGT is on the drivers bank and thats what you tune to, then at least you can install another EGT in the other bank when the engine is out.
Mine are fitted in the turbo exhaust housing before the impeller. I didnt want to drill the manifold. I have one each side.
so pretty much it is an engine out job to do properly... if i did fit one until then in the exhaust somewhere, i couldnt use the values, or trust it to tune with. But the engine could jsut be tuned another way (im not sure what normally gets used, wideband 02 and a knock sensor?), and i could use the readings purely as an indicator of improvement in temps vs worse exhaust temperatures? or will teh temperatures in the exhaust pretty much be the same after passing the turbo and doing all that work. does that sound right? im thinking if thats the case, i might just put one in the exhaust somewhere, and leave both intercooler and WMI intact until I get the engine out for something. Then I can do it properly either side, remove the intercoolers and tune by it? I guess that way I can at least have the WMI system set-up and running for a while, troubleshoot it, perfect its performance etc before I trust my whole engine with it working correctly..
Placing EGT's post turbo just won't give you a realistic value. There a many many factors that contribute to the EGT, not just ignition timing and AFR. Compression, valve overlap, and valve timing. Also there is not really an ideal temp either that signals "perfect tune" either. If I'm reading your posts correctly, you want to see if there's a measurable difference in EGT's with the addition of WMI and a change of IC. I don't think you really will see one. The benefits of lowering the intake charge with an IC and WMI and the slowing of the combustion (WMI), is all around what you do with that benefit, ie timing, compression, etc. So if you change nothing but lower your intake temps, then your exhaust temp will be roughly the same as without those benefits, assuming your not detonating. The AFR's remain the same, the ignition point remains the same, and amount of gas and it's compression/expansion rate and heat energy remains the same. When you increase your timing, on the same mixture, then shit changes. On the hotter mixture the timing advance may cause detonation, because the pressure in the chamber is now to high for the stage of the compression stroke, a cooler, denser mix, less pressure, no detonation, etc. What you aim to do then is see what sort of results you can achieve with your ignition and valve timing to suit the cooler charge and still remain within a safe EGT range. Anyway, Gas is out of the chamber, into the manifold, under pressure , because of the turbo, so retains basically all it's heat energy. This, is in a large part, what causes the turbo to spin. Hot gas's under pressure, rushing from a higher pressure, to a low pressure (dump pipe) environment, on expansion, looses alot of it's heat energy, no point reading EGT's from here, they would likely be about 200+ degrees lower than in the manifold. At WOT, your EGT's are usually around 800 degrees C. See this piccy of heat different in the manifold vs dump pipe
im sorry to be so harsh, but previous posters obviously have no clue about EGT based tuning and probing. sorry! to measure ACCURATE individual cylinder EGT changes, probes need to be mounted around 1-2" from the face of the exhaust port. however when i say accurate i mean instant changes in temp, which also require expensive equipment to be able to log measuring temp post turbine temps(around 50mm from the flange) is perfectly fine. however what you are reading is a combined cylinders average for the left or right bank in the case of a v6. example for a bank of cylinders #1=1000*C #2=900*c #3=950*c AVERAGE, of these would read 950*c post turbine. here is a link for a company that sells quite affordable gauges and sensors, they are very good quality, very responsive and are much cheaper because they don't have some jap tuners name printed on the front http://www.auberins.com/index.php?main_page=index&cPath=5_21&zenid=99cfb1690c95a1073a549602fc39e99e here is a link to a thermocouple that can be mounted post turbine, just drill the correct hole, screw the probe in and the clamp is used to keep it on. wont have to remove anything from the car. nice and easy. http://www.auberins.com/index.php?main_page=product_info&cPath=5_22&products_id=69 EGT readings are not like AFRs, they change for every setup and car, there isnt a right or wrong, only a ball park of ranges. They are good for logging load, and also can help you spot a lazy injector for example if you are cylinder monitoring. In your water/meth injection application, you'll want to measure a differential in temperature before and after. the system is running, log an average before the system is running, develop an average peak load temp. the use the water/meth and figure out what the average reduction in temps is. an effective method is to make incremental adjustments to the mixture and plot the averages on a graph, when you reach a point that you saturate the cylinder and you ignition system cannot ignite the mix totally, you will see a drastic drop in EGT temps, and as you increase past that you will actually see EGTs rise again as unburnt mixture is ignited in the exhaust manifold. i hope that covered everything you should know about setting it up, and what your trying to achieve. just pm me if you need any other help bud. sorry about the spelling, in a rush.
Apologise all you like, post turbine is not "an average" , in the collector may be an average, in the loosest sense of the word. Both turbo and dump sizing will have different affects on temperature post turbo, so unless you know all of this, accurately, then it is useless. And EGT based tuning...EGT's are a tool, you don't base your tune soley on the data from an EGT sensor. And don't show me links, 30 seconds on google will show you equally as much information in the negative.
I don't think there's much chance of getting an accurate reading from a egt in a log style manifold for a certain cylinder at all, maybe something remotely close, but not accurate.
please, provide me data logging of your experience to the contrary? i'm providing information, from what i have learned, through experience, not behind a keyboard, i didn't mean to offend you through providing a response. but, ill write it all down again. did you even read what i posted? or were you completely blinded by my earlier comment, that you choose to disregard the merits of my post? YES, post turbine EGTs are the average of all cylinders feeding that turbo, allowing for thermal losses, gas compression all taken into account it is still an average of cylinders. its common sense and really that simple. you think that if egts were 500*C accross all the ports your going to log 900*C post turbine? did i say anywhere it was a tool to base your entire tune you ding dong? i said its a variable number. which is EXACTLY what it is. i believe i said "EGT readings are not like AFRs, they change for every setup and car, there isn't a right or wrong, only a ball park of ranges." over time you'll find a trend developing of temp ranges suitable for parts longevity, and you can also find the limitations of temperature readings before parts exceed there capable thermal load... to simplify, shit lasts longer when its cooler, you cannot always cool things down enough due to high amounts of load, higher the load. higher the heap, more power = more heat its physics, so you learn a safe limitation and don't push to far beyond the envelope, if you do, shit will break. its an excellent tuning tool if you know how to use it. have a look at r&d in lemans car motors, thermal demands are extreme, every part is designed for a given thermal load, and they design a system to keep within its limits. why do some tuners pump out hand grenades from their dynos, and some pump out reliable cars making the same power numbers. 2 cars run identical setups and Air to fuel ratio (not lambda). what other tuning variables are there that do not directly affect AFRs? from my EXPERIENCE you will find that post turbo is approx 100*c lower than if measured at the port. logged over average duration and varying load events you'll see the trend. the exact temp is irrelevant, what you need is a base line, and then work your way up or down from that point. the exacting egt's are near irrelevant, its a broad spectrum, cars have performed at 11.4ars on alcohol based fuels and deliverd 850* EGTs peak hold load for 10 seconds, measured at the exhaust port. petrol based cars have also been tuned to 11.4afrs and seen 950*C peak hold 10 seconds. and another petrol car the same will read 900*c from a few small tweaks. Ive personally run a motor over 1300*c which survived for some time, and another under 900* which have popped quite soon... there is a vast array of variables. unless you are competent in thermal dynamics and physics, you will struggle to correctly calculate what your correct egt's should be at any given load point for peak torque/hp. so returning to my original post, YOU CAN LOG EGT'S POST TURBINE. it isn't as accurate, and isn't as instant in response. but for this given purpose it is totally suitable. i guarantee you the OP will log a reduction in average EGTs, and that is all that he is trying to measure. although you will be unlikely to notice any changes from the removal of an inter cooler. i wont post here again, pm me your number if you want to talk, takes too long to type this mumbojumbo cheers, dim
