EGT Temps: What is Normal/ What is too high?

[Red Dragon]

Hey everyone,

My car has an HKS EGT gauge. It has the sensor mounted on the HKS sport turbo EGT tap, so its getting a pretty true reading. When I'm cruising down the road at around 3k or higher RPM, I run arounf 1300-1400 F. When I'm pushing 1.1 bar for more than 5-6 seconds, I get up to 1600. Is this too high?? I was told that 1650 F is where I need to be worried. So how do you guys run higher than 1.1 bar w/o getting EGT up too high? And is 1300-1400 at highway speeds something to be concerned with?

I have Lexus AFM, RC 550's and run about 45-50 psi fuel pressure under full load.(low 30's at idle) I have the Montingney Vf meter, and at idle at runs green, so should be like stock levels, just 20% more fuel/air. I dont have a air/fuel meter or a wideband. Wondering if this is something I should get?

Thanks for any insight.
I do have my EGR removed, which could explain the cruising temps, but EGR shuts off at WOT, so I still have 1600 under WOT 1.1 boost, so that shouldn't affect that reading.

 

[Idealsupra]

where exactly is the sensor mounted? it sounds like in the exhaust housing of the turbo?

anyways all cars are going to have different EGTs.....1600ish is where shit will start melting so you definitley want to stay away from that....

 

[lagged]

change your fuel pump.

 

[Red Dragon]

change your fuel pump.

Its a new one, Mazda Cosmo three rotor fuel pump

Yes it is in the exh. housing, in teh predrilled tap for the gauge.

so are you guys saying that 1600 is too high for 1.1 bar, and that I'm not flowing enough fuel?

 

[GotBoost?]

Engine cound be fuel starving. I'd get a hi flow fuel pump and a new fuel filter (if you don't have them yet). Do you have an adjustable fuel pressure regulator (a-fpr) and a fuel pressure gauge? Then have it tune with and S-AFC (or similar fuel controller) at the dyno. All that's much cheaper and much less hassle than melting something in the engine.

 

[Red Dragon]

Engine cound be fuel starving. I'd get a hi flow fuel pump and a new fuel filter (if you don't have them yet). Do you have an adjustable fuel pressure regulator (a-fpr) and a fuel pressure gauge? Then have it tune with and S-AFC (or similar fuel controller) at the dyno. All that's much cheaper and much less hassle than melting something in the engine.

Yes, I have high flow fuel pump, digital fuel fuel pressure gauge, adj FPR, but no AF meter or SAFC. You think I should up the fuel pressure and see if it lowers the temps?

Other than that, anyone know a good shop in Houston that I could take the car to to have it properly tuned?

 

[encomiast]

Yes it is in the exh. housing, in teh predrilled tap for the gauge.

Not a very good idea.... the temps before and after the turbo can differ quite a lot. See here for some examples.

 

[IJ.]

Econ: While it's not ideal if he gets a good tune/baseline then makes note of what EGT's it runs normally he can then use it as a comparative tool.

The actual "number" doesn't really mean much as there are so many variables to consider but it can be used as an early warning system in case the car leans out.

I think we all get a bit hung up on numbers but if you get to know your car you can easily see impending doom if something is outside of it's normal range.

 

[tlo86]

Yes, I have high flow fuel pump, digital fuel fuel pressure gauge, adj FPR, but no AF meter or SAFC. You think I should up the fuel pressure and see if it lowers the temps?

Other than that, anyone know a good shop in Houston that I could take the car to to have it properly tuned?

i know of one in dallas if you are willing to make the drive, Marvel speed in rowlette, he races, and specializes in rotory / mazda but he works on a lot of MKIII supras

call don at (972)475-6448

there is also a turbo shop next door, and that guy would be a great help

 

[Red Dragon]

Not a very good idea.... the temps before and after the turbo can differ quite a lot. See here for some examples.

but this is where HKS put the EGT tap in their own sport turbo upgrade. Wouldn't they tell me to put it somewhere else if that isn't a good place?

 

[Red Dragon]

Ok so what are some steps to bring down EGT's? I already have the HKS intercooler, HKS DP, Full stainless 3" cat-back with random tech hi-flow cat. Is the next step adjusting the FP up? (it has lots of room to go)

Does a better radiator make much of a difference? What about a oil filter relocation kit (for the extra ~quart of oil)??

Thanks for your help everyone.

I guess I should invest in a wideband??

 

[Red Dragon]

i know of one in dallas if you are willing to make the drive, Marvel speed in rowlette, he races, and specializes in rotory / mazda but he works on a lot of MKIII supras

call don at (972)475-6448

there is also a turbo shop next door, and that guy would be a great help

Thanks for the rec, but thats a bit of a drive, as the car is a now a garage queen, only coming out for a few miles here and there on perfect days. Anyone else have a Houston recommendation?? Surely there has to be a good one here, I see a decent amount of mkiii's here.

 

[thesupraman]

Very true IJ. A/F ratio is not the only thing that will affect the EGT numbers. Ignition timing will greatly affect the number because if your ECU is retarding the timing due to detonation, the EGT's will climb because of the late burn cycle. One of my buddies with an MR2 was running 1800 degree EGT's with no damage to the motor (although I would not recommend it). Trying to tune by EGT's alone is not a good idea. Definately go for the wideband.

 

[Timmer]

So basically to keep egt's in a suitable range. Run the highest octane pump gas you have available to you, keep exaust backpressure to a minimum, tune for safe afr's(debatable, but low to mid 11:1's imho) and run only as much boost as the pump gas will safely and reliably allow. So if you only have 91 available, keep it closer to the 15 psi range and if you have 93-91 available 17-18 generally is an acceptable number. Those are just rules of thumb and by no means concrete mind you..That's pretty much all you can do besides making sure that your base timing it also set correctly.

 

[Red Dragon]

So basically to keep egt's in a suitable range. Run the highest octane pump gas you have available to you, keep exaust backpressure to a minimum, tune for safe afr's(debatable, but low to mid 11:1's imho) and run only as much boost as the pump gas will safely and reliably allow. So if you only have 91 available, keep it closer to the 15 psi range and if you have 93-91 available 17-18 generally is an acceptable number. Those are just rules of thumb and by no means concrete mind you..That's pretty much all you can do besides making sure that your base timing it also set correctly.

Thanks for the info.
If by "correctly" you mean 10o BTDC, then how are people retarding/advancing their timing with highly modded, high boost engines and keeping EGT's in check??
What does someone running 15psi "shoot for" in EGT's, and how do they accomplish that?

Thanks

 

[Timmer]

Thanks for the info.
If by "correctly" you mean 10o BTDC, then how are people retarding/advancing their timing with highly modded, high boost engines and keeping EGT's in check??
What does someone running 15psi "shoot for" in EGT's, and how do they accomplish that?

Thanks

Well 10 degrees btdc is stock, yah. Like others have said, every engine is different .So you can't really shoot for a number, per say.. People who have control over timing either have some form of standalone or a piggyback capable of timing adjustments ie. e-manage, maft pro, etc.. But that isn't really for keeping egt's in check but more for controlling detonation. Actually the more your retard your ign timing the higher your egt's will tend to be. People who run "high boost" are always running on race fuel of some sort and/or using alky/methanol injection to help stave off detonation. So to sum it up, people who have stand alone for instance set up their timing maps to retart timing under boost to help prevent detonation (as long as afr's are in check as well) It's kind of a balancing act, because when you retard timing you get a drop in power, efficiency, and egt's go up. So basically you have to try and find a happy medium and really it's the fuel grade you are using that dictates that for the most part. Hope I didn't jumble that up to badly..