Anyone installed Pre-Turbo EGT Gauge?

[desperado-c]

If anyone has done this, I think it would be interesting to find out what the temps for different mods are: intake alone, intake & DP/cat-delete, DP/cat-delete alone.

I have a crazy theory that the MS-CAI was pulled b/c intake alone was raising temps too much due to the restrictive stock DP. But, I note that the MS-CAI has been discontinued on both the MS3 and MS6 so maybe there's a problem with the restriction inherent in having a small turbo. If so, even with an aftermarket DP, it seems possible to me that the turbo is restrictive enough to raise temps by itself with a free-flowing intake. I won't be convinced otherwise until I see some pre-turbo EGT's.

In any case I'm back to stock on the intake. Kinda nice to listen to the engine unaccompanied by the intake suction noise, although I do miss the cathartic blowoff sound. Maybe I can make up for the loss with an aftermarket DP.

 

[69RMSP]

Interesting but I wouldn't mind seeing this as well... I didn't know they discontinued the CAI because the temp were rising...... So I assume you lose HP with the CAI or SRI now? unless you have it working with a tmic and DP?

 

[desperado-c]

Interesting but I wouldn't mind seeing this as well... I didn't know they discontinued the CAI because the temp were rising...... So I assume you lose HP with the CAI or SRI now? unless you have it working with a tmic and DP?

Whoa, there. Mazda hasn't said why they discontinued the CAI. This is all just my crazy theory. You definitely don't lose power with a CAI. They make great power for such an easy, cheap mod. But if there are elevated EGT's, it seems to me a likely cause of premature turbo failure.

 

[terbow]

they could have simply discontinued it cause it causes a lean condition. as much as people like to think the ecus are extremely adaptive, they still are tuned based on the car stock. if u change something its going to change the tune one way or another, even if the ecus can adapt. Almost every car ive dynoed with everything from drop in k & n to the normal air intake, has leaned the car at some point. not dangerously but probably enough for mazda to pull the plug on something they dont find necessasary to put out a retune for.

but leaner mixture will certainly raise the temps so your not far off. However the hotter combustion temps wil lead to detonation before turbo failure since your not running the turbo out of its efficiency range stock.


my egt is pre turbo. but i dont have a ms3 or 6

 

[desperado-c]

they could have simply discontinued it cause it causes a lean condition. as much as people like to think the ecus are extremely adaptive, they still are tuned based on the car stock. if u change something its going to change the tune one way or another, even if the ecus can adapt. Almost every car ive dynoed with everything from drop in k & n to the normal air intake, has leaned the car at some point. not dangerously but probably enough for mazda to pull the plug on something they dont find necessasary to put out a retune for.

but leaner mixture will certainly raise the temps so your not far off. However the hotter combustion temps wil lead to detonation before turbo failure since your not running the turbo out of its efficiency range stock.


my egt is pre turbo. but i dont have a ms3 or 6

I base this not on the lean mixture per se, but more on the BackPressure-To-Boost ratio which is reportedly more than 3:1 where 1:1 is optimal. My theory is that adding a free-flowing intake may further increasethe BPTB ratio to the point where EGT's are elevated to levels that are bad for the turbo. But maybe there should be other indications that wouldn't require a pre-turbo EGT gauge?

Any further thoughts?

 

[FORZDA 1]

.......I have a crazy theory....

Yep, nuf said...(hand)

 

[LBV]

terbow: What kind of egt's do you see in normal driving and what's the highest you've seen?

 

[desperado-c]

Yep, nuf said...(hand)

Back it up and educate the less knowledgeable. Preferably with pre-turbo EGT's or some other solid empirical evidence. From your sig and your posts elsewhere, you seem like a knowledgeable guy. I look forward to hearing why I'm crazy.

 

[FORZDA 1]

Back it up and educate the less knowledgeable. Preferably with pre-turbo EGT's or some other solid empirical evidence. From your sig and your posts elsewhere, you seem like a knowledgeable guy. I look forward to hearing why I'm crazy.

Well, I didn't say you're crazy, you did. Just take a look at what you asked. Essentially, "does an intake pipe before a turbocharger compressor wheel affect the post-turbine wheel EGT to the point of Mazda discontinuing the sale of a particular intake pipe?" The simple answer is no. The only way to significantly affect the post-turbo EGT is to increase the exhaust temp BEFORE the turbine wheel via more volumetric efficiency in the combustion chamber. The intake pipe ahead of the compressor and intercooler doesn't have very much, if any, effect on the air temps post intercooler (CAI vs SRI debates withstanding). The IAT with MS CAI run within 0 to +10 deg of ambient. The BAT remains unchanged by the CAI. Although we haven't seen anything official from Mazda concerning their reason for discontinuing sales of the MS CAI, I would think it is more related to water ingestion and the subsequent customer complaints concerning warranty.

I won't be convinced otherwise until I see some pre-turbo EGT's.

This statement tells me you're on your own...(cheers2)

Happy Motoring!

 

[desperado-c]

Well, I didn't say you're crazy, you did. Just take a look at what you asked. Essentially, "does an intake pipe before a turbocharger compressor wheel affect the post-turbine wheel EGT to the point of Mazda discontinuing the sale of a particular intake pipe?"

Hunh? Crazy or not, that's not what I asked at all. I said nothing about post-turbo EGT's. I'm sure there is plenty of info about post-turbo EGTs and we'd already know if those were dangerously high. If you're gonna try to grasp the essence of a question, it's a good idea to pay some attention to its important details.

The simple answer is no. The only way to significantly affect the post-turbo EGT is to increase the exhaust temp BEFORE the turbine wheel via more volumetric efficiency in the combustion chamber.

Well, duh. That's why I'm trying to find out what the pre-turbo EGT's are. And, given the increases people are getting with just an intake, I'd say VE is definitely being increased substantially. It's not a big jump to suggest that pre-turbo EGT's are also being increased substantially and maybe just not being detected post-turbo. Instead of a simple answer, how about one supported by relevant facts/principles and preferably with data specific to an engine with a small turbo and a restrictive exhaust?

The intake pipe ahead of the compressor and intercooler doesn't have very much, if any, effect on the air temps post intercooler (CAI vs SRI debates withstanding). The IAT with MS CAI run within 0 to +10 deg of ambient. The BAT remains unchanged by the CAI.

Well, finally a little specific data. But I don't see how it's relevant since BAT's can apparently remain unchanged while VE and corresponding pre-turbo EGT's are increased. Do you have any data which can be used to accurately extrapolate pre-turbo EGT's?

Although we haven't seen anything official from Mazda concerning their reason for discontinuing sales of the MS CAI, I would think it is more related to water ingestion and the subsequent customer complaints concerning warranty.

That's it? The potential for water ingestion is pretty fundamental to using a CAI. I haven't seen anything convincing about why it's suddenly a crucial issue for this particular car.

This statement tells me you're on your own...(cheers2)

It looks that way. I just figured at that at least one MS3/6 owner who installed a new manifold would install a pre-turbo EGT. Seems a number of Subie guys have done it, but unfortunately only one MS3 owner whose gauge was defective. So, I guess I was wrong. Without any indication of pre-turbo EGT's, I guess we'll just have to wait to see if Mazda does ever bring the CAI back and what changes they make to it.

Happy Motoring!

Thanks, you too. I am happier now that I have my restrictive stock box back on to balance out the restrictions imposed by the turbo and exhaust. And I'll be happier still when I get the power back by adding a good downpipe. I just hope I put back the stock box back on soon enough to avoid damage to my turbo. After all, just b/c you're crazy or paranoid, doesn't mean you're wrong!

 

[terbow]

terbow: What kind of egt's do you see in normal driving and what's the highest you've seen?

Idles around 800 deg

Cruising at 70 is around 1250 deg

in boost it goes anywhere from 1400-1550 i beleve. Ill have to double check that.

 

[LBV]

Granted I don't have an EGT, but the dashhawk reading for the cat sees me over 1600 on just a short burst on boost ... that scares the crap out of me if it's correct. (boom04)

And I'm running a step colder plugs to act as a better heatsink than the stockers.

 

[terbow]

Granted I don't have an EGT, but the dashhawk reading for the cat sees me over 1600 on just a short burst on boost ... that scares the crap out of me if it's correct. (boom04)

And I'm running a step colder plugs to act as a better heatsink than the stockers.

yea like i said im not sure. i havent looked. Ill take the car to kung fu tonight and ill report back what i get. Im running richc ause of the 626 mani so it might be lower than normal.

edit:

I am also running a step colder, however what i said was about spot on. It never went over 1500 during a full boost run. I only run 10psi though, and i run a lil richer than a stock ms3 so my temps should be lower.