max egt pre turbo temp for vnt17/22 with 3" kerma turbo back exhaust

I have a MyCruiseAgent egt probe thru my egr. What temp are you all seeing for vnt17/22 with 3" turbo back exhaust?

With the power level you are running you can melt the hot side of your turbocharger. I have slightly less power with a 2.5" down pipe and I can get the turbo inlet temperature up to 1700 with some effort: long steep hill, 5th gear, 100% throttle and up goes the turbine inlet temperature.

It is a standard recommendation to have an EGT gauge when you are running higher power levels. (146 whp, 267wtrq)

I've bumped 1650F for 10 seconds or so, 1400F for 2-3 minutes multiple times and 1200F for an hour. Turbo is fine (broke a piston though). I have a 3" DP and 4" for the rest of the exhaust. 11mm, PP502's, etc.

I'm told that the max rated temp is 1650F

ive got a Kerma 3"
with r520's and a 10mm pump i get about 1400. thats about it though... around here its gereally pretty flat and i dont tow so 20 seconds of that will put me in jail....

i dont have the fuely-est tune nor is my IQ set real rich (ie not a low #)

also using a mycruiseagent

1400 near the end of 4th

pegged the 2000*F (cobalt autometer) gauge easily when i was running my 17/22 - usually on very spirited runs at full throttle from bottom of 4th to top of 5th. My last dyno with that setup was 198hp/390tq. Probe was installed through the EGR port and was inches away from the turbine. Got hot VERY fast! temps always dropped quickly once took my foot off the accelerator.

OmegaRenegade said:

pegged the 2000*F (cobalt autometer) gauge easily when i was running my 17/22 - usually on very spirited runs at full throttle from bottom of 4th to top of 5th. My last dyno with that setup was 198hp/390tq. Probe was installed through the EGR port and was inches away from the turbine. Got hot VERY fast! temps always dropped quickly once took my foot off the accelerator.

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Wow.. and I thought I hit high numbers. I can get to 1700 rather easily and have hit 1850 or so on occasion - Cobalt EGT gauge with MCA EGR probe.

I dyno'd at 180HP/285TQ. How did are your TQ numbers ~ 105 ft lbs higher?

Raydee's got some sick Torque too at about 80 ft lbs higher. I just thought it was a 17/22 thing... Maybe it's not.

Got Bearings? said:

I dyno'd at 180HP/285TQ. How did are your TQ numbers ~ 105 ft lbs higher?

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Is that to the wheels? What dyno machine?

Pcar993 said:

Is that to the wheels? What dyno machine?

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Yes, to the wheels on a DynoJet

The turbo may be ok up to 1650F, your stock pistons however... not so much. Having seen way too many engines damaged from excessive fueling, I don't run above 1200.

Kevinski4 said:

The turbo may be ok up to 1650F, your stock pistons however... not so much. Having seen way too many engines damaged from excessive fueling, I don't run above 1200.

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1200?? Seriously?? Lame... Why do you even have PP520's and RC3? You might as well put a 2x4 under the "gas" pedal.

Just a quick question, then you can get back at it....what are you guys thoughts on r520s on a10mm? I plan to with other supporting mods(workin on the list) install the r520s. Just curious what your thoughts on the nozzle pump combo. Thanks guys
Also how long is the probe you all use for the EGR plate on the mani?

Ben Dur said:

ive got a Kerma 3"
with r520's and a 10mm pump i get about 1400. thats about it though... around here its gereally pretty flat and i dont tow so 20 seconds of that will put me in jail....

i dont have the fuely-est tune nor is my IQ set real rich (ie not a low #)

also using a mycruiseagent

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mine are set up by DBW with stage1 flow

given that im only seeing 1400 i may have them set up to stage 2 or even standard pressures. im only pushing 20 psi right now, with a tune that should come up a few psi so the fueling can also be increases. more flow=shorter injection window (with tune)

id also like to hear what others say regarding the combo as im sure its not optimal...

Got Bearings? said:

1200?? Seriously?? Lame... Why do you even have PP520's and RC3? You might as well put a 2x4 under the "gas" pedal.

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See Fix_Until_Broken's post near the top. He's seen high EGTs. He's also broke a piston. Anything above 1400 and you are rolling the dice.

Fix_Until_Broke said:

1400F for 2-3 minutes multiple times and 1200F for an hour.

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fix until broke is definitely a talented and intelligent individual. However, for lack of better words, "heres your sign"

i mean it is not unreasonable to expect the reliability with 1400 or even 1600

but if someone is doing so for an hour straight, obviously EVERYTHING inside the crankcase is getting quite hot.

All this being said, FUB never once made any kind of claim that he was upset at his tuner, or flabbergasted by what happened.
It appeared to me that he was somewhat of the thinking "i guess its about time"

he even asked for advice from others about adding oil temp gauges etc. and what he could do to keep this catastrophe from reoccurring. It appears that he fully plans to continue such use.

1200 degrees for 2 hours is also somewhat of a bazaar happenstance, however he tows. He knows this is likely what cracked the piston, and he knows that it could happen again. He is taking steps to prevent it, among them limiting to 1200 degree EGTs is not one ive read about. Of course i cant speak for him, but I doubt even HE would suggest others limit themselves so modestly in EGT.

Is 1200 a safe limit? sure. Is it a little ridiculous, imho yes, a little.

Those who are seeing 1600+, how is the smoke level with the tune? Can the EGT run that high with a light haze OR no smoke at all? I'm thinking some tunes/ adjustments people run are too agressive. The difference between a haze and a bunch of smoke is not much hp, but tons of EGT!

Originally Posted by Fix_Until_Broke said:

1400F for 2-3 minutes multiple times and 1200F for an hour.

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+2. it wasn't stabs of 1600*F, it was the long hill climbs for extended periods of time, and towing large loads on some of those runs that did the pistons in. Kevinski, you've got room for more everything.

robnitro said:

Those who are seeing 1600+, how is the smoke level with the tune? Can the EGT run that high with a light haze OR no smoke at all? I'm thinking some tunes/ adjustments people run are too agressive. The difference between a haze and a bunch of smoke is not much hp, but tons of EGT!

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good question

im sure some of the big turbo guys can give us some insight... Does EGT increase with HP or smoke? Im sure the answer is both, but im wondering how hot a smoke free 220hp tune would be compared to a similar level of smoke at, say 180, or 200...

in other words, if i was to absolutely optimize a 1722 (25-26psi) r520 and an 11mm pump with a 3" DP & exhaust (to keep this on topic) and a very low smoke tune (light haze on a dyno for instance) what kind of EGT would i expect to see.

And the towing was done on oversized tires and 5th gear in WI where the fastest speed limit is 65 and the rpms weren't above 2000 rpm often.

There have been times I have had well over an hour at the 1200 temps as well but that was with stock tires, stock 5th gear, strong and cold head wind towwing in WY. Still going on stock hardware with some supporting mods (tune, bypass filter, etc).

The piston broke while driving 45 MPH in 4th gear on my way home from work - no trailer, no significant load to speak of.

A couple weeks prior to that I was pulling the below trailer with a 2500lb mower and the ramp is like a huge sail which is what I suspect started the cracks in the pistons.


The whole story is in the "Show what you tow" thread starting with post 843, below are the highlights

Fix Until Broke said:

......It was all I could do to maintain 70 MPH. On the flats I was running ~15 psi boost steady state. I ran it up to 20-21 psi on the hills but coolant temps started to get over 220F so I didn't push it any harder. I ran the whole 100 miles with the windows cracked, full heat and the fan on 4 to keep the coolant temps below 220F. I turned the fan off once because my feet were about to start on fire and the scangauge temps went up 2 degrees every 5 seconds so I turned the fan back on at 228F and rolled the windows down a little more. It was ~30F ambient temp outside and I removed my lower and middle grille blocks so airflow shouldn't have been an issue. I'll need to look into possible other cooling problems as I've never had this kind of issue with keeping things cool, even in the summer.

I went 50+ miles with the boost never below 15 psi, coolant temps never below 215F, EGT's never below 1100F. IATs were 80-100F, engine RPM was 2000-2100.

Highest EGT's were ~1400F but typically 1200F-1300F

There was a 15-20 MPH head wind which does not help anything. This is the only time I've wished I didn't have the 205/70/15's instead of the 195/65/15's - that additional 6% bump in RPM's would have helped quite a bit from a power standpoint.

I slowed down to 60 MPH on the 2 lane roads and the coolant temps were a little lower (running ~215F typically, but still climbed over 220 on hills). I tried running slower but below 55-57 MPH (1700 RPM) I got on the wrong side of the torque curve and couldn't accelerate at all. Downshifting to 4th wasn't an option that I was willing to do unless I absolutely had to, so 58-60 MPH it was.

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You can see that there are cracks started on the #2 pistion and that there was definately flame on the edges of the bowls of the pistons. The texture of the aluminum pistion is wrinkled where each injector hole was.

I'm sure oil temps were very high as well (no oil temp gauge at the time)




My setup is relatively smoke free and it's my opinion that the typical well tuned (more/less smoke free) TDI on a US highway without a trailer/roof rack/etc won't be on the throttle hard enough and long enough to do any significnant damage to the engine or turbo.

I wouldn't think twice of 1500F EGT's if I wasn't pulling a trailer because I'd only be there for a few seconds at most - not long enough to get coolant and oil temps high enough to do the damage like I did.

I'm not saying you can't blow it up "on the street", but for the abuse that I put mine through pulling a trailer for 10k miles, I think you'd have to work reasonably hard to do so - again, on a well tuned TDI. Put in some crappy nozzles or overboost your turbo and you'll blow it up for sure.

There is no harm in limiting yourself to 1200F EGT's, you're probably just leaving some power on the table for a marginal gain in reliability. If that comprimise lets you sleep at night, then it's the right decision for you.

so much information. Thanks for taking the time to share

do none of you guys monitor EOT?? engine oil temperature?
i know on our trucks when egt's get toasty the oil temps shoot up as well. there is some heated speculation about whether it is oil temps that kill pistons

are these turbos (stock and aftermarket) oil cooled?? if so and you are running 1700* egt's oil temps would be much higher than desired.

I know it's totally different, but I'm around 440rwhp (7000+lbs...) and I rarely see EGT's over 1300.

it sounds like you guys could benefit from less restrictive intake/exhaust parts and maybe a bigger turbocharger. 1700* is quite toasty.

JMO, remember I'm no expert and just trying to learn and pitch in

"The turbo may be ok up to 1650F, your stock pistons however... not so much. Having seen way too many engines damaged from excessive fueling, I don't run above 1200."

I'm inclined to agree with the above for sustained use. Although I wouldn't worry about 1600-1700f if it's only for a few seconds. In my use(marine) I set the throttle to a certain rpm and sometimes don't touch it again for 5 or 6 hours. I consider 1100 maximum for this sort of duty, if I see any higher than that I pull the throttle back to maintain 1100 or a little less.

OmegaRenegade said:

pegged the 2000*F (cobalt autometer) gauge easily when i was running my 17/22 - usually on very spirited runs at full throttle from bottom of 4th to top of 5th. My last dyno with that setup was 198hp/390tq. Probe was installed through the EGR port and was inches away from the turbine. Got hot VERY fast! temps always dropped quickly once took my foot off the accelerator.

Click to expand...

Got Bearings? said:

Wow.. and I thought I hit high numbers. I can get to 1700 rather easily and have hit 1850 or so on occasion - Cobalt EGT gauge with MCA EGR probe.
I dyno'd at 180HP/285TQ. How did are your TQ numbers ~ 105 ft lbs higher?

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I'm pretty sure PDs can get away with higher EGTs. Still I'd be scared to see 2000deg.

I have a MCA block off with Newsouth gauge/probe. Pre head/block work i would see 1700deg temps, but i also cracked a piston clean in half. Now with the motor and head all done and R520s i don't even see 1500deg.

ak47tdi said:

I'm pretty sure PDs can get away with higher EGTs. Still I'd be scared to see 2000deg.

I have a MCA block off with Newsouth gauge/probe. Pre head/block work i would see 1700deg temps, but i also cracked a piston clean in half. Now with the motor and head all done and R520s i don't even see 1500deg.

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yeah im running the newsouth probe as well. I did notice that the MCA probe is a bit longer, and im assuming the NewSouth probe is a tad less than "ideal" as it may be a 1/2 inch out of the exhaust stream. Anyone have any thoughts on this? the newsouth probe is only about 3/4 inch shorter than the MCA probe, and in the MCA instructions it is suggested that you leave about 1/3inch poking out the top. does the remainging 5/12 inch-ish difference effect the reading greatly?

Thoughts?

Ben Dur said:

yeah im running the newsouth probe as well. I did notice that the MCA probe is a bit longer, but and im assuming the NewSouth probe is a tad less than "ideal" as it may be a 1/2 inch out of the exhaust stream. Anyone have any thoughts on this? the newsouth probe is only about 3/4 inch shorter than the MCA probe, and in the MCA instructions it is suggested that you leave about 1/3inch poking out the top. does the remainging 5/12 inch-ish difference effect the reading greatly?

Thoughts?

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I think it needs to be on the path of flow inorder to get true reading. Anything less would change temp. Significantly.

yeah i understad that, but is it out of the path i wonder... maybe ill have to do some work myself...........................................