Turbo Upgrade / Replacement (MY04/05?)

[HardwareBoB]

Your car is sufficietly intercooled, it's just heat soaked at the drags - it's a very specific problem in the exact circumstance of off street drags where you idle for ages, then go at 100%.

An intercooler waterspray (even a bodgy home made jobby) would make a significant difference.

[dr20t]

Alexei i agree with what you're saying but i feel you're confusing what im saying.

Probably way off topic but g/rev is measure of load in airflow (as registered by maf). Its peak cylinder pressure occurring at the momentary peak torque (ie the momenta in the rev range at which point peak torque first occurs, indicating point of peak intake charge speed [approahing Mach 0.61 being the theoretical intake speed limit]). This will generally coincide with engine's optimum efficiency in ingesting and exhaling the airflow.

So whilst peak airflow in g / second may not occur until later, its the peak torque that will result in greatest acceleration. So if peak airflow is down as a result of lower boost, it generally would indicate peak torque was either lower (because the new peak air speed occurred later in the rev range).

Torque is what gets you out of the hole, and airflow in g/ second is what will impact trap speed.

So both e/t and trap speed have been impacted by drop in peak airflow.

Mick

[dr20t]

Infact rethinking the above, if peak airflow dropped off then max load most definitely wouldve dropped (as load is directly correlated to airflow in g/sec as calculated by the maf, referenced to rpm)

So a drop in peak airflow by 13g/second would have impacted peak load by at least 0.13 g/rev assum

[dr20t]

Infact rethinking the above, if peak airflow dropped off then max load most definitely wouldve dropped (as load is directly correlated to airflow in g/sec as calculated by the maf, referenced to rpm)

So a drop in peak airflow by 13g/second would have impacted peak load by at least 0.13 g/rev assuming peak airflow at 6500rpm as 2jz points out

[2jz929]

Definitely over thinking it. It moves the weight really well at the moment and will continue to improve. It's only the Mrs car and she's happy with it (actually doesn't care haha).

[alexeiwoody]

Alexei i agree with what you're saying but i feel you're confusing what im saying.

Probably way off topic but g/rev is measure of load in airflow (as registered by maf). Its peak cylinder pressure occurring at the momentary peak torque (ie the momenta in the rev range at which point peak torque first occurs, indicating point of peak intake charge speed [approahing Mach 0.61 being the theoretical intake speed limit]). This will generally coincide with engine's optimum efficiency in ingesting and exhaling the airflow.

So whilst peak airflow in g / second may not occur until later, its the peak torque that will result in greatest acceleration. So if peak airflow is down as a result of lower boost, it generally would indicate peak torque was either lower (because the new peak air speed occurred later in the rev range).

Torque is what gets you out of the hole, and airflow in g/ second is what will impact trap speed.

So both e/t and trap speed have been impacted by drop in peak airflow.

Mick

I wasn't arguing with you about peak torque mick.

I was talking about peak power and trap speed, as you yourself agreed is the most appropriate thing to relate to g/s.

I was shaking my head because you suddenly brought peak torque into it - while telling me to "be mindful of where the peak airflow is" and that it's "in the early revs"....which it's not, because we're talking about airflow in g/s - completely different from peak torque in terms of rpm location. As 2z929 said himself - it's at 6500rpm.

Now, I completely agree with you about peak torque and it's importance and the flow-on effect on everything.

Unfortunately I didn't and can't comment on peak torque, since we only had the g/s reading - which indicates only peak power.

Hopefully that clears it up


In reply to your last comment:
We don't know what happened to peak torque. Yes, it's very likely down too, if peak power is down, but not necessarily. Without g/rev logs? We don't know 100%.

[dr20t]

As above, If peak airflow in g/s is down, then almost definitely g/ rev is down as load is a function of g/sec airflow (load in g/rev = (g/sec x 60) / rpm

So if peak airflow is down by 13 g/ second at 6000rpm then g/rev is down by 0.13 calculated as (13x60)/6000 which is 0.13 g/rev less.

Therefore using your reasoning that g/rev correlates to torque then torque is down too

*edit* - my comment about where in the power curve peak airflow occurs was probably confusing as yes I agree peak airflow will generally coincide at highest rpm where engine is still within efficiency

[kiahatsiu]

Slight change in conversational direction, but why not take a 500ml spray bottle filled with a mix of metho and water and spray a decent mist of the intercooler while you are waiting in the staging lanes? Or the classic esky ice bricks?
Edit, or fill a 9kg gas bottle with compressed air and give the cooler a spray every few minuets in the lanes. When you get to the front of the line you mate hangs on to the bottle and away you go.
edit2: http://www.vetnpetdirect.com.au/kincrom ... _a_7c66963 <-- one of these about 1/4 filled with water and ice and pumped right up, spray the cooler every minute or so in the lanes.

[2jz929]

Yeah next time I'll go I'll be more prepared for the heat soak and will have sorted the boost loss.

Pretty happy overall though, for $2.5k (including replacing a blown turbo) it has gone from a 15.1@89mph to a 13.8@96.9mph.

[Archie01]

Archie - as you probably noticed I was more replying to 2jz929, but quoted you to touch on the point that 13g/s does not amount to 3-4mph (to run a 100); it would need to gain closer to 30-40g/s.

Ok thats clearer.
2jz929 would you have the logs showing what the inlet temp was at the staging lights by any chance?

[2jz929]

Archie - as you probably noticed I was more replying to 2jz929, but quoted you to touch on the point that 13g/s does not amount to 3-4mph (to run a 100); it would need to gain closer to 30-40g/s.

Ok thats clearer.
2jz929 would you have the logs showing what the inlet temp was at the staging lights by any chance?

Logged intake temps are irrelevant as the intake temp sensor is in the maf sensor.

[kiahatsiu]

Spray this all over the place before your run.
http://www.jaycar.com.au/Service-Aids/C ... n/p/NA1000

[2jz929]

Spray this all over the place before your run.
http://www.jaycar.com.au/Service-Aids/C ... n/p/NA1000

That's a pretty cool idea. I'm going to check if a little thermo fan can fit underneath it as well.

[Archie01]

2jz929
If there is no other indicator of intake air temp at the throttle body that is logged by the ecu (to get post I/cooler temps) then wouldnt the underbonnet temps logged by this be a good comparative point for people with top mounts waiting in line at the drags even if the temp is logged near the maf?

Ps Ian that spray can idea is awesome

[kiahatsiu]

Spray this all over the place before your run.
http://www.jaycar.com.au/Service-Aids/C ... n/p/NA1000

That's a pretty cool idea. I'm going to check if a little thermo fan can fit underneath it as well.

https://webstore.spalusa.com/en-us/prod ... ector.aspx

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