Help needed, EGT went up?

[Big Will]

Hi all,
I have posted this on another forum but pretty much everyone with anything between there ears lurks here..

Over the weekend I fitted a new turbo to my LN130 surf.

The turbo is bigger in the:

Exhaust wheel (1mm exducer, 2mm inducer bigger)
Exhaust housing 0.63 A/R
Compressor wheel (53mm In 76.5 exducer)

When fitting this I also fitted a 3" dump pipe which I connected to my fexiback 3" exhaust.

Nothing else was changed (no extra fuel etc)

I have no wastegate and the turbo is running the same ~20psi that the CT20 was running.

For some weird reason the EGT has risen ~100 deg c, I can reduce it but the usual means (water/meth injection) but i was saving that as an ace up my sleeve.

Why would the Temp go up?

[ToyRover]

not sure why but what turbo did you fit and is this on a 2.4 or a 1kz

[SMOKEY]

Sort of thinking out loud with out getting my head completely around it but my first thoughts are, you have improved the turbo efficiency yet the fuel stays the same, I don't know if the same rule applies , more air and same fuel equals a lean fuel mix and lean fuel creates more heat. Or maybe your new dump pipe is not as good as the original, how hard would it be to change back to the original dump pipe and give it a test ?. Is your EGT probe pre turbo ? and if so what sort of Temps are you getting ?. I have a 96 Prado 1KZTE and I can hit 750deg C real easy. I am following the post on water injection with interest because the 1KZ pulls like a school boy but you can't keep your foot down because the EGT gets to high, we have just done 1000ks towing the caravan and it really gets me having to pull back to 2nd and keep to 2800RPM even up a gentle slope so as the EGT don't get over 600.

FITZY.

[Big Will]

not sure why but what turbo did you fit and is this on a 2.4 or a 1kz

This turbo is a DSR430 and its on a 5L

Sort of thinking out loud with out getting my head completely around it but my first thoughts are, you have improved the turbo efficiency yet the fuel stays the same, I don't know if the same rule applies , more air and same fuel equals a lean fuel mix and lean fuel creates more heat. Or maybe your new dump pipe is not as good as the original, how hard would it be to change back to the original dump pipe and give it a test ?. Is your EGT probe pre turbo ? and if so what sort of Temps are you getting ?. I have a 96 Prado 1KZTE and I can hit 750deg C real easy. I am following the post on water injection with interest because the 1KZ pulls like a school boy but you can't keep your foot down because the EGT gets to high, we have just done 1000ks towing the caravan and it really gets me having to pull back to 2nd and keep to 2800RPM even up a gentle slope so as the EGT don't get over 600.

FITZY.

I think you have is slightly confused with petrol mixtures, a rich mixture creates more heat in a diesel, the EGT is PRE turbo and im getting up to 620-640 DEG, I can get them lower easy without touching the fuel, but the point is they shouldn't have increased.

The dump pipe i have built wouldn't be more restrictive than what was there as it was stock vs a full 3"..

I will add pics.

FITZY, as for your 1KZ getting warm, just stick an exhaust on it, an intercooler and run as much boost as the ECU will allow any of these methods will reduce your EGT heaps.

[Big Will]

The new dump pie

[radar21]

maybe by removing wastegate it has increased temp

[Big Will]

maybe by removing wastegate it has increased temp

It never was running a wastegate.
Thanks
Will.

[rangimotors]

being a bigger turbo are you sure it flows more or at least as much as the other turbo?
Only thing i can think of it it is either pumping in less air (because it flows less) OR it hits boost later due to its size and because your running plenty of fuel its running way to rich and getting hot before you hit "boost"

??

[Big Will]

being a bigger turbo are you sure it flows more or at least as much as the other turbo?
Only thing i can think of it it is either pumping in less air (because it flows less) OR it hits boost later due to its size and because your running plenty of fuel its running way to rich and getting hot before you hit "boost"

??

Thanks rangimotors, This is where "The Team" are currently looking.
I doubt that the CT20 would flow anywhere near as much air as the DSR430, but what Im thinking is that because it takes a little longer to come on boost the heat is already there with the "off boost" enrichment it probably could be fixed with a boost compensated pump.

This will be the next step as far as fueling goes but i need to find some parts (if anyone can help LOL)

But, im going to get another turbo built, probably with a Holset compressor wheel that are designed for more higher boost applications as i would like to be running about 2.0 bar in the end.

[radar21]

must be a weapon of a 5l

[Big Will]

must be a weapon of a 5l

We have compared it to a 4.3 Litre Petrol Chev Blazer and unfortunately the yank tank didn't even compare..

Using the seat of your pants dyno it is about the same, maybe a little less go than my friends 1UZ-FE powered surf (only until he puts his turbo back on )

I don't really know why but i would like one of the most powerful L series engines in the country. it will suffice until I start building my 4.2

[rangimotors]

being a bigger turbo are you sure it flows more or at least as much as the other turbo?
Only thing i can think of it it is either pumping in less air (because it flows less) OR it hits boost later due to its size and because your running plenty of fuel its running way to rich and getting hot before you hit "boost"

??

Thanks rangimotors, This is where "The Team" are currently looking.
I doubt that the CT20 would flow anywhere near as much air as the DSR430, but what Im thinking is that because it takes a little longer to come on boost the heat is already there with the "off boost" enrichment it probably could be fixed with a boost compensated pump.

This will be the next step as far as fueling goes but i need to find some parts (if anyone can help LOL)

But, im going to get another turbo built, probably with a Holset compressor wheel that are designed for more higher boost applications as i would like to be running about 2.0 bar in the end.

cool will be interested to hear how the "team" go, i'm not even close to any sort of expect but like to take an interest. I don't know anything about the dsr430 but i'm sure you are correct. I remember something about the ct20's that are meant to be smaller than a ct26 but I did have a friend with a mr2 and he said the ct20's were a great turbo and far out performed the larger ct26. Could be a much different story though becasue I know there are many variants of the same model turbo but they call them all ct26 or ct20.

I'm sure you are starting to wish you could run an after market computer and do some fuel maps etc

Good luck

[crazyclark31]

being a bigger turbo are you sure it flows more or at least as much as the other turbo?
Only thing i can think of it it is either pumping in less air (because it flows less) OR it hits boost later due to its size and because your running plenty of fuel its running way to rich and getting hot before you hit "boost"

??

Thanks rangimotors, This is where "The Team" are currently looking.
I doubt that the CT20 would flow anywhere near as much air as the DSR430, but what Im thinking is that because it takes a little longer to come on boost the heat is already there with the "off boost" enrichment it probably could be fixed with a boost compensated pump.

This will be the next step as far as fueling goes but i need to find some parts (if anyone can help LOL)

But, im going to get another turbo built, probably with a Holset compressor wheel that are designed for more higher boost applications as i would like to be running about 2.0 bar in the end.

cool will be interested to hear how the "team" go, i'm not even close to any sort of expect but like to take an interest. I don't know anything about the dsr430 but i'm sure you are correct. I remember something about the ct20's that are meant to be smaller than a ct26 but I did have a friend with a mr2 and he said the ct20's were a great turbo and far out performed the larger ct26. Could be a much different story though becasue I know there are many variants of the same model turbo but they call them all ct26 or ct20.

I'm sure you are starting to wish you could run an after market computer and do some fuel maps etc

Good luck

Your mate with the mr2 would have had a ct20b which were are better turbo than the ct26. Would make a good upgrade for a surf i reckon.

Big Will
If your motor is heating up because of the big fuel load at low boost then it should come back down when high boost is acheived. How quickly is beyond me.Prob a bit of a risk to find out too. If its a bigger turbo egts' should have come down as bigger turbo vs smaller turbo = same pressure but more air. As a bit of a guess maybe there is far to much air and you are actually running to lean????? What happens if you drop the boost down 5psi????

am watching this with interest as am getting into modding diesels myself

[Big Will]

I think that maybe because the turbo is coming on a little bit late, it could be starting the heat chain reaction to so the addition of the extra boost cant control it. The reason im thinking this is because when it gets to about 20 psi @~630 deg c the temp seems to drop a little as the boost continues to go up.

Im going to have a play around with the aqua-mist water injection system to see what happens. Want to try get the temps down to about 500 deg..

[Big Will]

Something I also forgot to try, a smaller exhaust housing to try and speed up the boost process.. Although this goes against my better judgment If i can get an exhaust housing cheap enough Im willing to give it a try.

[crazyclark31]

yeh but if your running a bigger turbo it should be pumping more air @ 20psi than your old turbo was.

[Big Will]

Yeah that's true but if your starting with quite a bit of heat ~400 before it even comes on boost it might be quite hard for the turbo to get it under control. I want to try the smaller exhaust housing as its only a easy job and I will see what happens there.

[suzolla]

Hi,
Just a comment about Boost and Flow for a Diesel.
At a given RPM the engine will consume a certain amount of air, if you then start increasing the inlet pressure it will consume more air, the amount of flow is directly related to the pressure or boost, if you put a bigger turbo on that gives more flow it will also have more pressure, but will require more exhast pressure to drive it. ie can't have more pressure for the same flow at the same engine rpm, this is assuming no butterfly in the intake as is the case for most diesels. Also you can not have more flow for the same intake pressure.
The above applies for a constant fuel input.
Hope that makes sense.

I suspect that at the lower revs when there is lots of fuel your bosst and hence air flow is low, how does the exhaust smoke compare to the old turbo during initial acceleration

Cheers
Tim

[Big Will]

Hi,
Just a comment about Boost and Flow for a Diesel.
At a given RPM the engine will consume a certain amount of air, if you then start increasing the inlet pressure it will consume more air, the amount of flow is directly related to the pressure or boost, if you put a bigger turbo on that gives more flow it will also have more pressure, but will require more exhast pressure to drive it. ie can't have more pressure for the same flow at the same engine rpm, this is assuming no butterfly in the intake as is the case for most diesels. Also you can not have more flow for the same intake pressure.
The above applies for a constant fuel input.
Hope that makes sense.

I suspect that at the lower revs when there is lots of fuel your bosst and hence air flow is low, how does the exhaust smoke compare to the old turbo during initial acceleration

Cheers
Tim

Shot Tim, that makes perfect sense..
I didnt have any smoke before I fitted the turbo, and im not 100% sure whether have any now as the surf is off the road again getting a new coat of paint.
So as I thought adding a bit more low end boost would help?


What would be the best plan of attack? Using a slightly smaller exhaust housing (try and get boost sooner and the expense of exhaust back pressure) or going to a smaller compressor wheel (try and increase spool by lowering rotational mass)? Both?

Will.

[suzolla]

Hi Will,
I'm certainly no Turbo expert, just a Mech Eng with a good tech knowledge and a bit of common sense.
Also don't have any actual experience in playing with Turbos, but hope to soon when I start playing with my 1HDT.
Regarding the best approach there will be far more knowledgable people out there who can hopefully advise.
Couple of comments.
Boost compensator will help.
Tricky balancing act to get off the line perfomance and loads of power at the top end as well.
Would not have thought that changing the rotational inertia by a small amount would make a noticable difference.
Cheers
Tim

[Big Will]

Thanks bud, Im going to just experiment and see what happens.
I will keep an eye on my EGT's while swapping turbos and toying with other bits and pieces..

Im looking forward to my 1HD as well, its going the same way as my 5L, but im using a SC14 supercharger to compound with another big turbo, should be fun.

[suzolla]

Interesting you should say that, was considering the same thing but with an M90 charger and W to A intercooler.
Do you know of any links for Super and Turbo Chargers in tandam.
Cheers
Tim

[Big Will]

Not really, just need to look up twin-charging, all sorts of stuff round..

[crazyclark31]

had a think and the aussies are using (i assume) the equivilent size garrett turbos(gt2864(.64 hotside)) on the td42 and making very good power so maybe your turbo is abit big. if was the case then your prob right about yuor off boost temps.

You could see if you can get a .57 hotside for your dsr and see how it goes?
have found the outerlimits forum really good for turboing info.

[Shane]

Yeah that's true but if your starting with quite a bit of heat ~400 before it even comes on boost it might be quite hard for the turbo to get it under control. I want to try the smaller exhaust housing as its only a easy job and I will see what happens there.

I would try the .58 hot side housing if thats the one you mean?
thats what I had on the TD42(DSR 430) and run much lower egt's than the other turbo I run,which had quite a large exhast housing.

Best of luck

Shane

[Big Will]

Yeah that's true but if your starting with quite a bit of heat ~400 before it even comes on boost it might be quite hard for the turbo to get it under control. I want to try the smaller exhaust housing as its only a easy job and I will see what happens there.

I would try the .58 hot side housing if thats the one you mean?
thats what I had on the TD42(DSR 430) and run much lower egt's than the other turbo I run,which had quite a large exhast housing.

Best of luck

Shane

Yeah Im going to try and find one before I start building another turbo. That and get the aquamist setup going.

[darinz]

Sounds like the problem has been found but I'd put my vote on over fueling at lower revs before peak boost. It is a tough one as you want the extra heat down low to spool the turbo quicker but have to balance excessive egt. Compensator is one way but it does sound like exhuast housing is too big.
Like a few have said bigger compressor is more efficient so should give more air for same boost and at a lower temp. Can you map egt at rev points as that will tell you? I'd be chucking it on a dyno to tune as all would then be revealed but mapping egt vs boost vs revs.

[Big Will]

I found the problem although it was a bit late for the turbo unfortunately.

I was getting boost pressures up to about 27psi and the EGT's had dropped enough to be satisfactory ~550-580 deg and it seemed to have quite a reasonable amount of power.
So the next day I went for another ride and I could only manage 15 PSI so the head scratching began..
To cut a long story short I took all the intercooler plumbing off and found a rag ( ) stuck in the intercooler covering 90% of the core, after removing it I was hoping to have unleashed a massive amount of power first impressions were that it did, but after closer inspection Ive found that the turbo is in need of a rebuild or replacement.
I would love to know how much boost the turbo was actually making before it died but my boost gauge is on the inlet manifold and was after the blockage.

So this weekend I am going to remove the damaged DSR430 and get it's exhaust housing machined to suit a Garrett 'N' Trim exhaust wheel (which is slightly bigger) and a new Garrett core installed with possibly a GT35 compressor wheel supplying the air. Will see how it goes.

[mudslut]

That sucks man

[Big Will]

tell me about it. Im just happy im really good mates with a turbo guru who has all the bits and pieces to make it better, then again if the DSR turbo is fixable I will give it another chance for sure.