anyone familiar with tunning egts

I'm using a wideband o2 on my jz drag truck. I was thinking about adding an egt probe to each cylinder to help with tunning and trouble shooting. Can someone give me a briefing on how to tune using them.

 

I understand the different temps would tell if one cylinder is leaner or richer than the other by temperature. What would I do just richen or lean that one cylinder until temps match then retarget a/f over % to make sure the whole map is even on all cylinders. I'm just trying to figure out if I'm in the ball park on how they work before I order

 

What are you trying to achieve here? Match afr and /or egt on all cylinders? Do you have a way to tune each cylinder? Need more details on your setup and what you are trying to achieve.....

 

Yea ms3, sequential injectors, lq9 coils, 1000cc injectors, water meth, nitrous, haven't decided turbo yet probably some kind of billet ball bearing 88mm 1.10 ar., I also have vvti. 8an line 850lb fuel pumpfor injectors and a walbro 255 for nitrous. A friend of mine works for a guy who drives a professional drag car (outlaw 10.5 car very low 6s over 225mph and a pro mod that I seen make a 3.70 1/8 mile pass nitrous car)he recommended getting egt probes per cylinder so I can target egts and then target a/f so I can log both every run that way if something happens I can find the cylinder easier. He didn't explain it too well and I'm assuming you tune egt first then richen or lean the map to get desired a/f. I'm just trying to confirm if that's how you tune with them.

 

If you do this, be very precise on egt probe locations and angles. For other reasons, but similar, we often use multi point egt in aircraft.

There can be some variation in temps and not have issues.

There is a company that does sell tuned injectors nozzles. Aircraft do not use electronic injection like a car but rather a constant flow type design.

Consider that if each cylinder draws in the same amount of air, then each nozzle should spray the same volume.

If you are tuning via egt, then realize that each cylinder is making a different amount of output. Yes adjusting FF can optimize fuel burn, but ideally differences should be very small to balance output per cylinder.

Consider the best design to tune would be a setup like an old drag car with Hilborn individual air intake horns and separate exhaust. Then pulse waves from other cylinders have no effect.

EGT is very good indicator to stay rich of peak and produce optimum power without burning something up or detonating.

I did not see it mentioned, but if you had AF for each cylinder and EGT, then you would have a means to match many parameters and balance heat inside the engine. The data would also allow you to interpolate each cylinders BMEP, and realize where to gain airflow to gain balance.

PK

 

Tune egt and afr as close as possible cyl to cyl. Having egt and afr in each pipe and having a way to log them will help tuning everything and see which cyl running hot/cold and lean/rich afr. When doing this go in small steps.....na, low-high psi, water inj low-high, n2o low-high ect and work your way up the power scale keeping a close eye on logs of egt andafr along the way while making any adjustments. Also take all the notes you can on anything/everything including weather conditions during logs. Have you made any passes or dyno runs with current setup?

 

I have not made any passes yet. I pulled the dash gutted it (harness, air box, brackets I don't need anymore). I needed it gutted so I can widen the trans tunnel for th400 trans. My header has 6 equal lengthtubes probably about a foot long stainless. All I have is one wide band. I did make a pass with the 1jz with stock turbo at 8lbs with 100shot ran a 11.20. That was probably close to 400whp I'm going for 1000whp at 2000lbs instead of 2500lbs.

So how far away from cylinder do you mount egt and what angle or does the manufacturer tell you that with the kit

 

You want egt as close as you can to cylinder for most accurate reading. Wideband on each runner can be further downstream. Make sure your runners are large enough for the power you plan to run as well as turbo. Also since running n2o spray direct port if you can for best power. If spraying water it may be best to spray in stages such as before turbo to lower discharge temps and before head/direct port for best results. Thing about water nozzle on each cyl each may spray slightly different making egt slightly different complicating things. With n2o cooling effect you may not need as much water injection or depending on fuel used may not need much. Could just spray water before turbo only to help efficiency and overall cooling without effecting one cyl or another... make most of your power from boost plus n20 and good fuel vs relying on water inj for as much power. You going big single turbo, parallel twins, sequential twins? Intercooler specs. This is sounding good man... more specs on your rig man..... would love to see it in person as well. I am in nc.....

 

Depending on the turbo I get (lag) I may run 2stages n2o 25shot off trans brake on inlet side of turbo through 1st then just 100shot wet right before tb to try to lower ait which depending on temps and pressure could result bout 150hp gain. The meth is just to reduce detonation I may only use it for on the street because I'm too far into the build to redo the fuel system for e85. Stock ports on 2jz heads are good to 1300hp all I'm going to do is smooth the casting and the header is a little larger than ports 1/8th in maybe so that'll probably match them. Its a t4/t6 header divided. Going big single . Intercooler everything 3in, water/air seprate pump ice box, 91mm throttle body either ls style or q45.272cams vvti, h beam rods forged pistons, billet main caps arp fastener.
Seeing it in person wouldn't be a problem
Its still under construction I got to get a cage done but I don't gave a tubing bender . Just stuff like tgat and money slowing me down.

 

I think you would be fine having a street tune: (600-700hp) low boost running water/meth injection and high test fuel and a strip tune: (1000hp+)high boost n20 water/meth race fuel. Either way try to have a decent size water/meth cell. 1/4 to 1/2 that of fuel cell. Where are you in sc? Race country in my area...plenty of guys can build you a cage round here, if you had the money.....my bud has his own fab shop in concord nc and does cages all the time but mostly exos for off road. He does awesome work and could do the cage for ya if you told him specs you wanted.....

 

As far as where to mount the egt probes. Angle wise, if you ar not in a straight portion of pipe, ensure the angle is not moving the probes tip closer or further from the exhaust valve or spark plug. As far as distance goes, I would check with the egt manufacturer. In some cases when to close to the heat, the probes fail early. Sometimes the failure mode is the probe will bulge and pop. With this type failure you need to be concerned about foding a turbine wheel.

You might also consider adding a final tit probe to represent turbine inlet temp. This good track so that the turbo does not get cooked.

PK