443 replies to this topic

[Scuffers]

only looked at a few VX's, but the IAT's to me seem very slow in reading...

 

as in either the sensor is quite (thermally) bulky/slow or the ECU reading of it is damped (which for an NA would be pretty normal)

 

as you lift from WOT, I would expect the AIT's to spike 10-20C instantly, then slowly work their way down again, or jump back down if you open the throttle significantly again.

 

EG:

 

 

as you can see, soon as you close the throttle, the AIT's rise (and this trace is showing how slow the AIT reading is too), once you open the throttle again, they go back down.

 

 

[smiley]

Probably our ecu that is slow to respond.

 

[slindborg]

Probably our ecu that is slow to respond.  

Or more to the point, calibrated to filter it to stabilise the calculations.

[Scuffers]

yup...

 

other point worth making is that if the engines happy running at X boost and Y IAT's, then reducing the AIT's further whilst a laudable goal, does not actually gain you anything (unless you're going to speed up the SC or add more advance)

 

by reducing the AIT's, you should actually see a reduction in boost, as the air mass you are dealing with will not change (that's a function of the SC drive ratio and air intake temps to it minus a bit of air leakage around the rotors).

 

not suggesting 90C is good, but are you actually having to pull timing off to keep out of det at this point and thus losing some potential HP?

 

and before you rush off and install water injection, just consider for a moment what effect this will have on your laminova cores... (assuming you're planning on using it at the SC inlet?)

 

Lastly, saw a comment about the crank vent earlier, in a SC car the very last thing you want is to recirc crank venting into the engine, oil vapour has a terrible octane rating and will effectively de-octane your fuel charge significantly, seem a lot of engines pushed into det because of this.

 

catch tank and filter away from the intake is the go..

 

 

 

 

 

 

 

[smiley]

not suggesting 90C is good, but are you actually having to pull timing off to keep out of det at this point and thus losing some potential HP?

 

The Z22SE ecu (incl obdtuner) is set to dial down from 57 iat.

I'm not really into exact science on this. On the german forum they use the DIN70020 correction and conclude roughly a 3% of hp loss at every 10 degrees.

 

That would make a 250hp stage II a 220hp system when hitting the 90's.

 

What i', still trying to find out is how long our the ecu takes to go back to original ignition when it goes back to under 57 degrees. 

Edited by smiley, 22 June 2014 - 08:35 AM.

[Scuffers]

 

not suggesting 90C is good, but are you actually having to pull timing off to keep out of det at this point and thus losing some potential HP?

  The Z22SE ecu (incl obdtuner) is set to dial down from 57 iat. I'm not really into exact science on this. On the german forum they use the DIN70020 correction and conclude roughly a 3% of hp loss at every 10 degrees.   That would make a 250hp stage II a 220hp system when hitting the 90's.   What i', still trying to find out is how long our the ecu takes to go back to original ignition when it goes back to under 57 degrees.

 

that's not the same.

 

that calculation is based on the AIT into the SC, as in it's how you calculate the air mass for a given volume.

 

once the air is into the SC, that all goes out the window as once past the SC, the air mass does not change with temp, it's fixed (unless you have a hole in your manifold!), raising it's temp just increases it;s pressure at this point.

 

the DIN calcs are base on intake air temps to the engine unit (ie, the supercharger in this case).

 

when you dyno a car, you put the dyno's IAT sensor in the air intake path (ie, the air the filter is in) Not into the intake manifold.

 

 

 

 

 

[CHILL Gone DUTCH]

Scuffers does this graph show what your explaining
I posted it some time ago and people thought is was strange that the temps went down on wot

Edited by CHILL Gone DUTCH, 22 June 2014 - 09:25 AM.

[smiley]

The germans had a similar discussion on using the DIN that way. 

The result however (loosing about 3% on every 10 degrees) does comply with what people are feeling on track or on a very hot day. 

To bad we can't seem to exactly pinpoint the loss. 

 

 

[Steve.i.am]

  think about the airpath when the engine in on very light load and the SC by-pass is open.  

So we've seen several data traces now where intake temp increases on smaller throttle opening/light load. And I have thought about the air path when the bypass is open. Struggling to conclude why temp goes up. So with the valve open, the manifold is in vacuum - that's what opened the valve. Here air is drawn in from the charger intake before the compressor directly into the manifold and I assume follows normal path from there - ie through the laminovas. So how is it getting heated to the point it's hotter than compressed air from the charger on WOT?

[CHILL Gone DUTCH]

I no this doesn't show the actual numbers of power loss Bit it does show that there is significant loss on the second lap as the stage four turbo goes past me Earlier in video I have legs on the turbo in a straight line but when I hit the power on the straight I felt the power loss The Tmap was reading 70 degrees when power dropped badly

Edited by CHILL Gone DUTCH, 22 June 2014 - 09:52 AM.

[fezzasus]

I no this doesn't show the actual numbers of power loss Bit it does show that there is significant loss on the second lap as the stage four turbo goes past me Earlier in video I have legs on the turbo in a straight line but when I hit the power on the straight I felt the power loss The Tmap was reading 70 degrees when power dropped badly

 

But that's known as per smiley above. ECU starts pulling timing above 57 deg. C

 

Obviously this limit is for an NA and has been carried over, so perhaps there's some scope for safe operation above that.

[CHILL Gone DUTCH]

Wonder if it pulls even more ignition as the temp rises more and more

[Steve.i.am]

But I thought we'd established this retarding is done from intake temp pre-charger. So nothing to do with these temps we are looking at from the TMAP..?

[CHILL Gone DUTCH]

I don't have anyway of monitoring pre charger temps My point was is the magic number nearer 70 degrees after charger Before power loss Or is it something which starts earlier and has gradual power loss Unfortunately I could tell you how the temps were prior to loss of power As I was driving

[smiley]

But I thought we'd established this retarding is done from intake temp pre-charger. So nothing to do with these temps we are looking at from the TMAP..?

 

Then mounting a tmap would be much worse, as that is in the manifold (hotter location) versus the old temp sensor pre throttle, of which i would think it should show about the same as outside temp. (which i remember it did before i rewired it to tmap)

 

Of course Peter put in some logic to make the tmap work on a charged setup.

Edited by smiley, 22 June 2014 - 10:51 AM.

[fezzasus]

But I thought we'd established this retarding is done from intake temp pre-charger. So nothing to do with these temps we are looking at from the TMAP..?

 

If you're running a TMAP then that's the only temperature sensor.

 

Basically, set up as an NA with a separate MAP and Temp. sensor, you won't have it pulling back ignition timing

 

Set up as a TMAP, the temperature is of the charged air and it will pull back timing.

[CHILL Gone DUTCH]

But I thought we'd established this retarding is done from intake temp pre-charger. So nothing to do with these temps we are looking at from the TMAP..?

  If you're running a TMAP then that's the only temperature sensor.   Basically, set up as an NA with a separate MAP and Temp. sensor, you won't have it pulling back ignition timing   Set up as a TMAP, the temperature is of the charged air and it will pull back timing.

I'm only guessing here but the charged temp will be higher than inlet temp before pulling ignition

[Steve.i.am]

But I thought we'd established this retarding is done from intake temp pre-charger. So nothing to do with these temps we are looking at from the TMAP..?

  If you're running a TMAP then that's the only temperature sensor.   Basically, set up as an NA with a separate MAP and Temp. sensor, you won't have it pulling back ignition timing   Set up as a TMAP, the temperature is of the charged air and it will pull back timing.

Ah I see, so obd tuner feature then. All those of us on CS maps and obd tuner without TMAP are using inlet temp pre charger. And I'm not aware any of those are having detonation issues?

[CHILL Gone DUTCH]

It' pulls ignition for a reason We use Tmap sensor because of more info for ecu Something to do with speed density

Edited by CHILL Gone DUTCH, 22 June 2014 - 10:58 AM.

[smiley]

Retarding ignition from 57 is an oem feature, not an obd tuner feature.

(i had the same loss of power feeling on my CS basemap on a hot day)

 

On last years LOT day at Zandvoort Peter did change the 57 to a higher value on one of the suffering speedsters and the owner complained about performance loss.

After checking with Peter later, he mentioned he leaves it to default 57 by default to protect the engine.

 

 

 

Edited by smiley, 22 June 2014 - 10:57 AM.