Car Cannot Take Timing

[Dose Pipe Sutututu]

are you able to get an EGT probe into the setup?

Just buy a ling long dim sim one and weld a bung to the downpipe.. would be curious to see what temperature it's hitting

[Ben C34]

Is time to load it up with probes!

pre and post ic temp

pre and post ic pressure

pre turbo vaccuum

exhaust temp

exhaust back pressure

probe probe probe

[blah_blah]

You could get a garden hose with mist nozzle to spray onto the cooler during a run. You can put a lot of water on that way and keep the core very cold.

If you were to do this, you would definitely be wanting to monitor the intake temps. Simply putting a bare thermocouple onto the outside of the hot and cold pipes and wrapping with a rag will give you a good guide to the air temp within (and you need a multimeter or TC handheld). I know you say the cooler return pipe was cool to the touch when run before....but if you want to go hunting further then this is an option to pursue.

I would look at measuring the suction in front of the turbo, just in case the inlet turns out to be restrictive (collapsing, whatever). A 10 kPa Magnahelic dP gauge would do that job (if it's sucking more than 10kPa negative then it's very bad indeed!).

A 300 kPa pressure gauge for measuring ex manifold pressure.

The 10 kPa dP gauge could be useful for measuring the pressure drop across the intercooler.

To summarise all that, people are concerned about a number of things. Hot inlet air being the main one. You could get hot inlet air from a bad cooler, from turbo inlet being too restrictive, from intercooler or pipework being too restrictive, from turbo hot side being too restrictive. That last one might be more about reversion contaminating otherwise clean and cold inlet mix in the cylinder rather than directly making hot air before the engine.

Cheers for the input

Don't think the tuner would appreciate his whole floor getting wet though lol

That U bend doesn't look too bad, however I can't help but keep eyeing the cooler.

Everything else sounds spot on. Try doing some tests per the above, and try another core if its possible.

When I had my RB25DET dynoed, it would ping its brains out, and no amount of timing would solve it. Then the dyno owner (not the operator) commented that RBs need FUEL to prevent detonation.

Not sure if thats the issue with my setup though

are you able to get an EGT probe into the setup?

Just buy a ling long dim sim one and weld a bung to the downpipe.. would be curious to see what temperature it's hitting

Is time to load it up with probes!

pre and post ic temp

pre and post ic pressure

pre turbo vaccuum

exhaust temp

exhaust back pressure

probe probe probe

Probes galore! Might need to send it to a mechanical & tuner workshop to run tests

[Dale FZ1]

Tony can you tell us just how much timing it is taking at full load? 12 degrees, 18, or 8? What does your tuner feel it should be taking?

If it's making 310rwkW from a 2.5 litre engine by 4500rpm on pump 98, that is a significant amount of grunt.

No indicator that the power is falling over, simply that the tuner is backing out of the runs. You have indicated that the engine is quiet, so no knock through the headphones?

Throw a bit more info out there.

[scotty nm35]

I think it was around 8 or 10 degrees at MBT and still knocking on the ears. I think he mentioned it should take another 8 or 10 usually on e85.

The runs were aborted due to concerns with the ID1000's mainly, they have since been flow tested and found to be fine.

Sorry Tony, I just can't think of any other reasons it won't take more timing, I just hope the machinist didn't skim too much off the head, or it wasn't already machined previously. Perhaps a lower boost actuator might be a good idea for now, so at least you can get the tune sorted.

[Dale FZ1]

What concerns with the injectors? Running out of duty cycle? Provided AFR are stable the injectors should have no bearing on timing figure.

10 degrees does seem way under what could be expected, especially on E85.

I misinterpreted Tony's comments and thought it was not knocking.

Given the power figure and rpm mentioned, what amount of boost is being pumped in? That is a LOT of power for a RB25 at 4500rpm.

[wolverine]

They would have to skim a shed load off to cause these issues.

The CAS is worth checking/swapping and I would re-time it from scratch.

I had a bitch of a time with my Stagea with power maxing out around 220rwkw. Timing belt was originally changed by the compliance workshop. Out of sheer desperation I had the car re-timed from scratch (despite being told that it was fine) following a similar issue that Guilt Toy had with his R33. I have no idea whether the timing can appear correct at the top but be out at the bottom but the car makes the power it should now and takes the timing at peak torque and up top like a neo should. It is more sensitive at peak torque and likes more fuel there than my R33 but Trent would be all over that anyway.

[scotty nm35]

What concerns with the injectors? Running out of duty cycle? Provided AFR are stable the injectors should have no bearing on timing figure.

10 degrees does seem way under what could be expected, especially on E85.

I misinterpreted Tony's comments and thought it was not knocking.

Given the power figure and rpm mentioned, what amount of boost is being pumped in? That is a LOT of power for a RB25 at 4500rpm.

Compared to similar turbo's Stao tests it seems way down on power for the 20odd psi its running. Although the torque was skyrocketing at 4500...

We were worried one injector was flowing less causing lean knock in that cylinder, the other cylinders running only a little rich would easily compensate, and the wo2 would read 12:1 at the tailpipe. I have seen it happen so often with e85 I am setting up an injector test jig for myself. Short of a wo2 sensor in each runner, it's the only way to be sure they are flowing well.

[blah_blah]

Given the power figure and rpm mentioned, what amount of boost is being pumped in? That is a LOT of power for a RB25 at 4500rpm.

About 22 psi

The CAS is worth checking/swapping and I would re-time it from scratch.

CAS is definately on the list of things to check

Thanks for all the help guys, we will run through various checks on the car to resolve the issue.

Once resolved ill post up what the issue was. And ill even EFT the first guy who was the closest

[Dose Pipe Sutututu]

When I had my RB25DET dynoed, it would ping its brains out, and no amount of timing would solve it. Then the dyno owner (not the operator) commented that RBs need FUEL to prevent detonation.

I'm sure Trent from STATUS/Chequered/URAS knows what he's doing

Best possible way to diagnose, EGT & Wideband into each runner (one at a time or preferably 6 at once).. could be just a few cylinders knocking etc.

[Ben C34]

About 22 psi

CAS is definately on the list of things to check

Thanks for all the help guys, we will run through various checks on the car to resolve the issue.

Once resolved ill post up what the issue was. And ill even EFT the first guy who was the closest

You know if you do every suggestion at once you could get out of paying anyone!

All the best getting it sussed.

[GTScotT]

OK...... Just for my own thoughts, what AFM volts is it pulling and what does Trent say about the relationship between volts and ability to make power?

If he tried to add boost in stead of timing does it continue to pull more volts or do they plateau also?

The reason why I ask is because I was not convinced 240kw was the most my SS1PU had to give, and my tuner showed me that when he upped boost further it would knock and not pull any more volts on the AFM. He said that was an indication the turbo itself was maxed out, be it front or rear. He said if there was an issue outside of the turbo it would have still pulled more volts trying to make more power. (Yavuz @ Unigroup)

What is the situation on this for you? Note; I do appreciate that you are running a Nistune and making monster power already, so whatever AFM you are running is POSSIBLY already maxing out before you run into issues.

[blah_blah]

You know if you do every suggestion at once you could get out of paying anyone!

All the best getting it sussed.

Lol, all in good fun, too get a brainstorm going!

But I'm a man of my word

OK...... Just for my own thoughts, what AFM volts is it pulling and what does Trent say about the relationship between volts and ability to make power?

If he tried to add boost in stead of timing does it continue to pull more volts or do they plateau also?

The reason why I ask is because I was not convinced 240kw was the most my SS1PU had to give, and my tuner showed me that when he upped boost further it would knock and not pull any more volts on the AFM. He said that was an indication the turbo itself was maxed out, be it front or rear. He said if there was an issue outside of the turbo it would have still pulled more volts trying to make more power. (Yavuz @ Unigroup)

What is the situation on this for you? Note; I do appreciate that you are running a Nistune and making monster power already, so whatever AFM you are running is POSSIBLY already maxing out before you run into issues.

I have no idea Scott, it was't really discussed

FYI the afm is a z32

[GTScotT]

In that case I believe you are armed with some new questions for le tuna.

[Tangles]

HDI cooler may not be able to do it's job past 310kw

Could very well already be past it's peak efficiency.

I'd seriously be looking at buying a jap brand name cooler such as greddy or hks.

I used a small apexi return flow unit off a 180sx on my Stagea and it couldnt tune past low 200's kw on a Sliding performance turbo due to the coolers small size / heat soak. Upgraded to a larger used hks core and gained another 20kw with minor alterations to the tune. Then upgraded the turbo for more again

Was a fair while ago so memory is a bit hazy, but I recall the cooler was holding the engine tuning back significantly......

[Mitchee]

Dont bother with wideband sensors in manifold runners, absolutely pointless on a turbocharged vehicle.

In your first post you mentioned that this issue was present on the old turbo:

• Car went on the dyno on the old setup and when it hit 280rwkw and not making anymore power it was thought that the turbo was too small causing back pressure. Car could not take timing up top. So changed the turbo.

Is there visual signs of knock when trying more timing? Engine movement/pops of smoke out of the exhaust. Perhaps the Nistune is detecting false knock and pulling timing, giving the effect of a 'brick wall' and not taking any further ignition timing/feeling like it has low octane fuel. The similarity in the two dyno graphs also leads me to believe this may be the case also. Remember you're dealing with a factory ECU with large amounts of correction tables which may be interfering here.. Can your tuner temporarily use an alternate ECU to at least rule that out? Or have someone on a timing light during a run to confirm commanded ignition timing is actually being applied.

[scotty nm35]

It is knocking on knock ears, and visibly popping black clouds at the same time. I'm sure Trent has been down that road many times, he could tune a Nistune RB in his sleep.

[blah_blah]

HDI cooler may not be able to do it's job past 310kw

Could very well already be past it's peak efficiency.

I'd seriously be looking at buying a jap brand name cooler such as greddy or hks.

I used a small apexi return flow unit off a 180sx on my Stagea and it couldnt tune past low 200's kw on a Sliding performance turbo due to the coolers small size / heat soak. Upgraded to a larger used hks core and gained another 20kw with minor alterations to the tune. Then upgraded the turbo for more again

Was a fair while ago so memory is a bit hazy, but I recall the cooler was holding the engine tuning back significantly......

Hrmm then what would be the reason of it being ok on the stock engine at 280rwkw, but not ok with the new engine old turbo at 280rwkw. And then bigger turbo jumping to 315rwkw

Dont bother with wideband sensors in manifold runners, absolutely pointless on a turbocharged vehicle.

In your first post you mentioned that this issue was present on the old turbo:

Is there visual signs of knock when trying more timing? Engine movement/pops of smoke out of the exhaust. Perhaps the Nistune is detecting false knock and pulling timing, giving the effect of a 'brick wall' and not taking any further ignition timing/feeling like it has low octane fuel. The similarity in the two dyno graphs also leads me to believe this may be the case also. Remember you're dealing with a factory ECU with large amounts of correction tables which may be interfering here.. Can your tuner temporarily use an alternate ECU to at least rule that out? Or have someone on a timing light during a run to confirm commanded ignition timing is actually being applied.

Scotty can confirm this better than I, as he was watching the smoke out of the exhaust

But there were puffs of smoke im pretty sure when the engine would hit the "brick wall" on both 98 and e85

Also tuner did bring out the timing light during the tune to make sure everything was ok

Edit: Scotty too quick

Edited January 30, 2014 by blah_blah

[MagicMikeZ32]

Surely you would check base timing before you started?

[MagicMikeZ32]

We were worried one injector was flowing less causing lean knock in that cylinder, the other cylinders running only a little rich would easily compensate, and the wo2 would read 12:1 at the tailpipe. I have seen it happen so often with e85 I am setting up an injector test jig for myself. Short of a wo2 sensor in each runner, it's the only way to be sure they are flowing well.

Been there...

Big single exhaust on a vg30, wideband in tail showed 11.5:1. Single cyl running way lean due to injector not flowing however being masked by the other 5.