4 EGT gauges

[Sotarts]

Has anyone thought about installing 4 EGT gauges to monitor EGT's of each cylinder? The cylinder at the end of fuel rail is obviously going to be slighty leaner, considering the slight fuel pressure drop off at the end of rail. Has anyone even done it? What are your thoughts on this?

 

[toshi128]

Originally posted by aovsi
Has anyone thought about installing 4 EGT gauges to monitor EGT's of each cylinder? The cylinder at the end of fuel rail is obviously going to be slighty leaner, considering the slight fuel pressure drop off at the end of rail. Has anyone even done it? What are your thoughts on this?

I think having one EGT gauge should be enough if you install the probe on #1 runner, since it is supposed to be the highest temperature of all. and the rest of the runners are not as hot as the #1 cylinder... then just measuring the highest temp should be enough... my thoughts...

 

[Tevenor]

There is no reason you can't run 4 EGT's. Does it really gain you that much without a standalone and some way of detecting knock in each cylinder? Not really.

Thread Moved.

 

[1_vicious_gsx]

There is no pressure drop from one side to the other. Fuel comes in one end and the regulator/relief valve is on the other. If you are taking a pressure reading at the regulator (let's just say 45psi as an example) then pressure is equal all the way through the injector rail. If the fuel rail were a restriction (which it isn't) then there would be a loss of pressure. Think about it. The diameter of the fuel rail passage is much larger than amount of fuel at the injectors tips. If the fuel rails were a problem we wouldn't have to buy aftermarket regulators to put on the end of them to deal with excess pressure/flow relief from a high volume pump. The only indication of a fuel rail restriction or flow problem would be if the fuel pressure kept dropping as rpm's & boost went up. Even then I would look at the fuel pump to be the problem first.

Anybody care to add an opinion to mine feel free to do so.

 

[markmakeitso]

It might be nice to know how each cylinder is burning, but without individual control over the injectors you can't do a lot with it. I have heard from some other sites that the fuel rail is restrictive enough to cause a difference between cylinders, but most people (especially people not selling aftermarket fuel parts) agree that there isn't a real problem.

 

[nine5raptor]

there is a site somewhere around here that talks about the restriction in our fuel rails...they were made smaller in the middle to easeir facilitate prod. I'll see if I can find it.

 

[Tevenor]

http://www.stevetek.com/R-FuelSys.html

 

[nine5raptor]

yeah, I was just rereading that when you posted, but I was actually thinking of another site for the 3kgt guys. Some of them machine out the whole fuel rail to a constant diameter and there was a snippet and some pics of out fuel rails as well.

 

[nine5raptor]

^ our fuel rails as well

 

[nine5raptor]

BINGO! http://www.proplusfx.com/fuel/

 

[kscott]

I've wondered about maybe doing this. Not for the purpose of fine-tuning each
cylinder (although that would be really great), but to deal with the eventuality of
an injector getting dirty and its spray pattern messed up, and therefore some
random cylinder starts running lean; I'd like to know if/when that happens.
The more I think about it, though, the more I think it's not worth the risk of
having EGT tips maybe break off, or having to replace them 4 times as much
when they open-circuit. I also wonder if, when an injector gets dirty,
does it typically flow less fuel, or does the amount of fuel stay about the same
and just spray in a more uneven pattern?

 

[Unreal]

Its been done many times by many different people. Every time they found out the #2 cylinder runs the hottest. Thats why TRE, and many others put the EGT in that cylinder. Look at DSMs with melted/cracked pistons, 95% of the time #2 is the 1st to go.

 

[HighPsi91]

Yep... every motor I ever fried happened on #2. Personally I wouldnt place too much faith on the Stevetek conclusions. According to his conclusions 90% of the fast DSMs have to be using some sort of fuel system voodoo.

 

[GTM]

Originally posted by aovsi
Has anyone thought about installing 4 EGT gauges to monitor EGT's of each cylinder?
...
Has anyone even done it? What are your thoughts on this?

Sure, and done it including repeaters as well. The repeaters were for marine installations where one unit was at the helm and a second unit at the navigation station below deck.

However, a _better_ solution could include 6, 7, 8, or more sensors / probes AND a _rotary_ switch. You will need to know if you can cut and splice the sensor wires and the type of probes the instrument will accept, e.g. J or K are the most common. Once you know this you can install the 4 in each ex. port by drilling a 1/4" hole, 4 CHT sensors which mount under each spark plug, another in the exhaust down pipe for an average reading or brake calipers to know when brake fade is eminent etc. The rotary switch(s) must have at least 2 conductors for each connection.

For the CHT you would probably want an instrument which went from 0º or 100º to about 1700º rather than a 400º - 1700º. You can get small decals for pasting on the outside of the meter for writing your own scale in addition to the painted scale. I posted elsewhere that there are other sensors which can be held in place by a flat spring in a topical contact rather than a probe and others which can be glued to the surface these are usually for lower temp measurements and don't require immediate response time.

With one 5 (or more) position rotary switch you could then select #5 and route into a 4 position for the CHT probes if you wanted to know how all the plugs were behaving. This keeps the investment down and doesn't clutter up your secondary instrument installation for other important gauges such as oil temp, boost, ammeter, etc.

Cheers,
GTM

 

[Nick 4g63]

#2 as in counting from the passanger side or driver side? thanx

 

[GTM]

Originally posted by Nick 4g63
#2 as in counting from the passanger side or driver side? thanx

Japanese cars or USA?? hehehe

With _few_ exceptions #1 is the cylinder closest to the the crankshaft pulley and when standing in front of that pulley the engine will rotate clockwise. Detroit V8's are not always laid out this way and I cannot comment other than consult the owners manual.

The firing sequence of a inline 4 cylr will also be 1,3,4,2 which effectively splits the crankshaft loads in half to reduce crank windup. Consider what would happen if the firing order were 1,2,3,4... when it got to 4 it would then leap the full length of the c/shaft and impart a power stroke considerable distance away and something is bound to fatigue with the load surge.
.......

On the VTEC site there is mention of the Westech instruments for EGT, do look around and be a knowledgable consumer.

Cheers,
GTM

 

[LaserRST]

I think there are easier ways as well as less expensive ways to monitor injection problems.... but in aviation they do exactly that. I think only cuz an engine problem at 30,000 feet vs. our lil turbos is a more of a problem. Early detection here is more serious. The EGT is to monitor lean conditions under boost, checking your plugs after every race day would be a good idea, and one less expensive than 4 EGT guages. It just seems not very economical for its purpose since the EGT is a monitoring device and not a tuning device, much like AFR guage. Now if there was a switching device that was cheaper, like the way O2 sensors work, that could send a warning in the event of a hot cylinder that would be more along practical. My 0.02

 

[DSMJim]

What Tevenor is saying is correct. HOwever it is only correct on our cars. This is a major problem on Honda's and Miatas. The miata espically. They blow the last cyl all the time on cars because of fuel starvation. One of the big miata guys makes a dual feed rail for miata specially to fix this problem. (called Vishnu or something)

We are lucky our cars come turbo from the factory and they designed some of these things into our setup, however guys with non - turbo cars have a lot more to deal with than we do.