Ok, so looking at the info on this site and various others, the opinion is 3" dump pipe off the turbo, then 2.5" the rest of the way with some resonators to stop the drone on a 2LT. The question I'm wanting to know is: Will this have a detrimental effect on the engine/turbo? I understand the turbo will boost higher, is the lack of back pressure going to allow over-speeding of the turbo, causing it to fail in a short period of time? (subaru's are notorious for this) Is the boost increase within toyotas "safe" working zone?
Also, is the injector pump capable of compensating without having to be modified immediately?
Just doing a bit of research before i modify. As it's my daily driver I don't want to be fixing it every week.
Many Thanks
Dan
Reliability with larger exhaust
I run a 2.5 inch exhaust off the original dump pipe, and have had no issues with overspeed etc.
Most people I have spoken to about exhaust pipes off 2lt's have run a 2.5inch from the dump pipe. This seems to provide enough of an improvement in moving the heat away from the motor.
My understanding of boost levels is that they correlate with the amount of fuel being thrown into the cylinders, and the waste gate settings. More fuel contributes to more exhaust which spins the turbine faster. The speed of the turbine is then limited by the action of the waste gate. I think that an over speed situation would not arise because of the larger dump pipe unless both the wastegate and fuelling were allowing it to occur.
There is room for adjustment with the existing injector pump via the max load screw, boost compensator plunger, star wheel etc. That said I would be cautious about doing this, using a boost gauge and pyrometer so you know exactly what is going on. Make sure your cooling is sorted out too coz of course these little donks do crack heads.....
Most people I have spoken to about exhaust pipes off 2lt's have run a 2.5inch from the dump pipe. This seems to provide enough of an improvement in moving the heat away from the motor.
My understanding of boost levels is that they correlate with the amount of fuel being thrown into the cylinders, and the waste gate settings. More fuel contributes to more exhaust which spins the turbine faster. The speed of the turbine is then limited by the action of the waste gate. I think that an over speed situation would not arise because of the larger dump pipe unless both the wastegate and fuelling were allowing it to occur.
There is room for adjustment with the existing injector pump via the max load screw, boost compensator plunger, star wheel etc. That said I would be cautious about doing this, using a boost gauge and pyrometer so you know exactly what is going on. Make sure your cooling is sorted out too coz of course these little donks do crack heads.....
Toyhatsu wrote:
The speed of the turbine is then limited by the action of the waste gate. I think that an over speed situation would not arise because of the larger dump pipe unless both the wastegate and fuelling were allowing it to occur.
What can happen tho with a larger exhaust is the "vacuum" after the turbo will draw exhaust thru the turbine instead of the wategate. This is what gives the boost increase from just putting on the exhaust. In extreme cases the wastegate is too small to cope and overboost and over-speeding occurs. Cue one blown turbo. Some vehicles are notorious for this, others are fine. I'm just wanting to make sure the 2LT is in the "fine" catergory.
As for cooling, it is all standard. Had a good flush out, but temp guage doesn't move on a long steep climb or anything. Anything else I need to do? Intercooler is on the list, prob plumb it in while it's at the exhaust shop.
Rollux wrote:As for cooling, it is all standard. Had a good flush out, but temp guage doesn't move on a long steep climb or anything. Anything else I need to do? Intercooler is on the list, prob plumb it in while it's at the exhaust shop.
The Surf temp gauges have three positions: Cold, Operating Temp, Cracked Head.
Seriously, the factory temp gauge will not budge a milimeter until it's too late, install an aftermarket temp gauge.
I was hoping that somebody who had done this mod (and there must be somebody) would pipe up (sorry for pun) and you would have a more definite opinion as opposed to a discussion on how turbos work!
I agree with smurf182 re the temperature gauge. Doubtless you have already ticked the thermostat box and made sure your water pump is doing its thing. If you are trying to extract some performance I would be looking at a radiator upgrade as well. Stitch in time saves nine etc etc
I agree with smurf182 re the temperature gauge. Doubtless you have already ticked the thermostat box and made sure your water pump is doing its thing. If you are trying to extract some performance I would be looking at a radiator upgrade as well. Stitch in time saves nine etc etc
I fitted a big bore exhaust to my 2LTE when I first got it 120000KM ago.
I can't remember the size but it was matched to the Turbo outlet flange and is the one size from the flange through a non restricting turbo muffler to the rear of the vehicle, when driving it has a nice turbo whistle.
The exhaust modification has given a slight increase in performance with no turbo problems. I have had to fit a new head as the old one cracked in about six places.
I have stated in previous posts my thoughts (read Exhaust Gas Temp) on what causes heads to crack and what to do about it.
Fit an exhaust PYROMETER gauge and drive off that, you will soon see how different driving techniques give different temperature readings.
SPEND NOW/ SAVE LATER,
FITZY.
I can't remember the size but it was matched to the Turbo outlet flange and is the one size from the flange through a non restricting turbo muffler to the rear of the vehicle, when driving it has a nice turbo whistle.
The exhaust modification has given a slight increase in performance with no turbo problems. I have had to fit a new head as the old one cracked in about six places.
I have stated in previous posts my thoughts (read Exhaust Gas Temp) on what causes heads to crack and what to do about it.
Fit an exhaust PYROMETER gauge and drive off that, you will soon see how different driving techniques give different temperature readings.
SPEND NOW/ SAVE LATER,
FITZY.