Boost leak testing a 1HDT

[mudgudgeon]

I was curios about turbine housing and wondering if theres lag on take off?
Doesn't make sense with the smaller turbine housing though.

Is AFR ok across the rev range?

 

[doug720]

High EGT's are too much fuel or not enough air. So if the turbo, IP, and engine are rebuilt and good, and there is no exhaust restriction, how are the injectors?

One or more bad injectors?

Nothing else has worked.

 

[Malahki]

High EGT's are too much fuel or not enough air. So if the turbo, IP, and engine are rebuilt and good, and there is no exhaust restriction, how are the injectors?

One or more bad injectors?

Nothing else has worked.

Injectors were done about 1000km before the engine rebuild. They were then cleaned and retested at the same time the IP and engine were rebuilt

 

[doug720]

IDK...Something is wrong?

 

[fitzmooney]

Could be a faulty EGT gauge or probe.

 

[Tapage]

Despite trying with another Pyro / probe advancing my IP timing lead in more higher EGT's in my case at least ..

I do have 315 with stock gears in my 80 and if I allow to my EGT's can fly .. but I have add intentionally bunch of diesel in my IP

 

[mudgudgeon]

Could be a faulty EGT gauge or probe.

Maybe that simple.
Were thermocouple wires cut short or installed as supplied? Shortening the cables reduces resistance and the gauge will read higher than it should.


On EGTs, if you continue to push it hard what's the upper limit?
When playing with the tune on mine, I saw egts go above 900C (1650F).

Taking a little fuel out of the tune dropped the absolute upper limit back to 800C (1400F), 750C max in normal driving conditions.
If 1350F is the upper limit of egts, I'd still consider this safe. If you push it and they climb above 1400F, then it's getting risky.

 

[Malahki]

Guages were replaced but probe was not. However I did unwittingly shorten the wires on the probe when installing the new gauges. I did not notice a difference in the reading but I have a new probe and will replace it.

EDIT: To answer your other question if i dont back out of it the EGTs will hit low 1400's

 

[Malahki]

So looks like a tuning issue after all. At the advise of Foreal I tried a run with my boost compensator disconected.
Resulting in:
EGTs under 1100 max
AFRs at 28:1
Boost 13lbs max
And a serious lack of power!! Topped the hill at 80kmh (50mph)
But it does confirm what many of you have been saying that theirs too much fuel despite the 21:1 AFRs I was previously reading

 

[Malahki]

I turned the boost comp star wheel out 3 whole turns, rotated the fuel pin to a leaner profile and turned the fuel up 1/8 of a turn.
Results:
EGTs 1250 Max
AFRs 23:1
Boost 13psi
Power is still not great. Topped the hill at 95kmh

EDIT: I should note that these last two test runs are not a true comparisom of EGTs with my previous results because having less power and slower speeds the auto tranny is dropping into 3rd gear. However when running the 21:1 AFRs and manualy dropping the trans into 3rd I would still see 1300+

 

[fitzmooney]

Just as a matter of interest, you can shorten K type thermo-couple wires any amount and it won't affect the reading.

 

[Malahki]

Just as a matter of interest, you can shorten K type thermo-couple wires any amount and it won't affect the reading.

Good to know, thanks

 

[mudgudgeon]

Good result.
Tuning is a black art!
It's a fine line between optimum power and too much fuel.
I'd be tweaking a little more and chasing a little more boost and max egt of 13-1350F, but depends on your appetite for risk.

 

[Malahki]

Good result.
Tuning is a black art!
It's a fine line between optimum power and too much fuel.
I'd be tweaking a little more and chasing a little more boost and max egt of 13-1350F, but depends on your appetite for risk.

Yes a black art indeed, considering the experience of the people who already failed at tuning it for me.

My appetite for risk after 2 year and over $10K invested is extremely low!! Lol. Yes I am going to keep tweaking it myself until i find the sweet spot and run it as is until I get at least 1000km on the motor. Then the plan is to up the boost and add an intercooler

 

[nz1HDThdj81]

Yes a black art indeed, considering the experience of the people who already failed at tuning it for me.

My appetite for risk after 2 year and over $10K invested is extremely low!! Lol. Yes I am going to keep tweaking it myself until i find the sweet spot and run it as is until I get at least 1000km on the motor. Then the plan is to up the boost and add an intercooler

Hi did you ever sort this out? I have noticed my intake gasket leaking (time for a replacement). I'm having similar problems up hills especially. I have the ct26, overhauled injectors, rebuilt injector pump, running factory internal wastegate, front mount intercooler, hpd oil catchcan, snorkel and 4in custom intake.