12 replies to this topic

[2deano5]

Smiley said this in another thread:

 

Both oem ecu and obdtuner start dialing back ignition as from 57 degrees celcius temp.

One of the dutch drivers asked Peter to tone that down a bit at zandvoort this year, but it's in there as a safety precaution, so left in there as default. 

If you feel like you will be hitting high temps, you need to consider water injection. (on hot days, the dual pass mod, large header tank and very expensive max size pro alloy prerad is not helping one bit) 

Maybe leevx's new manifold design also helps. Time will tell.

 

By the time you hit 90 degrees, you will have lost about 50 bhp....isch.  

 

SO, this has got me thinking, (assuming smiley is right?)

 

This is saying that at regular high supercharger use (WOT etc) the Pro Alloy prerad/laminavo set up does not cool the manifold sufficiently to keep the intake temps down. The answer is to water cool the intake to solve this or redesign the cooling system.

 

Questions? 

1. Could you not just run without a prerad (stage 1 style) and water inject? Obviously you would go through quite a bit of water?

 

2. If you are use water inj what size pre rad would be optimal ? would a smaller pre rad mean using more water or is the limiting factor the laminavos so a smaller pre rad (chiquchento/mocal?) would make very little difference?

 

If my thinking is completely wrong please educate me but If I run water inj with a smaller pre rad vs a pro alloy would I really be losing out or would we have to take some intake measurements to find out?

 

Cheers Deano

[smiley]

I think we have a long way ahead of monitoring and conclusions ahead.

All info i got on this so far is from people with various configurations using the tmap sensor to give info.

All of them are running water injection now though.

 

 

 

 

 

 

[techieboy]

 6 years of Stage 2 SC's with no temperature related worries (and no failures) until OBDTuner came along and people started dicking about with the IAT sensor. Ignorance is bliss.

[Steve.i.am]

Just for my own understanding (so that I can follow this thread) - the temperatures mentioned - what are they referring to exactly? Intake charge temp? At what point? Certainly the standard ecu has no post-charger intake charge temp sensor/input? I wasn't aware obdtuner did either but perhaps wrong? Could someone explain? ta

[Steve.i.am]

Ah - my post crossed earlier ones - so TMAP sensor monitors intake temp as well as pressure then? IAT sensor was the one in the intake before charger I thought?

 

Not sure I understand the statement..  "Both oem ecu and obdtuner start dialing back ignition as from 57 degrees celcius temp."

 

How does the oem ecu do that then?

[techieboy]

Yep, OEM ECU measured intake temps through the IAT sensor in the inlet tract, pre-charger (so effectively ambient air) and was ignorant of anything further downstream.

 

OBDTuner can use a TMAP sensor and measure intake temps in the inlet manifold.

 

Obviously, the second option will see much higher temps and with the exception of it possibly backing things off too early, is probably the better option though the first option is what has been used on every SC conversion before OBDTuner came along, without any issue (overly conservative mapping/extra fuelling to suit, maybe?).

[Captain Vimes]

Edit:- Techie has already answered..

Edited by Captain Vimes, 14 January 2014 - 10:49 AM.

[smiley]

 Ignorance is bliss.

 

  So we loose a few horsies on a hot day. Who cares.

[Captain Vimes]

But isn't the issue that the oem ecu doesn't see the true temp and doesn't pull the timing back which leaves a real risk of engine damage?

[smiley]

Not true temp, but the map sensor calculates the air density and manipulates the ignition based on that.

http://en.wikipedia....wiki/MAP_sensor

That is why both oem ecu and obd without tmap retard ignition when it get's hot.

 

Edited by smiley, 14 January 2014 - 02:34 PM.

[Captain Vimes]

Thanks Smiley. To test my understanding, although the standard ECU doesn't see the true temperature, in a hot environment the air pressure reduces and therefore the ECU will essentially run as if the car was at less than WOT (reduced amount of fuel, less advance etc). As the temperature gets really high the density drops significantly which results in lower power?

 

Back to the op's question:-

 

 

This is saying that at regular high supercharger use (WOT etc) the Pro Alloy prerad/laminavo set up does not cool the manifold sufficiently to keep the intake temps down. The answer is to water cool the intake to solve this or redesign the cooling system.

 

Questions? 

1. Could you not just run without a prerad (stage 1 style) and water inject? Obviously you would go through quite a bit of water?

 

2. If you are use water inj what size pre rad would be optimal ? would a smaller pre rad mean using more water or is the limiting factor the laminavos so a smaller pre rad (chiquchento/mocal?) would make very little difference?

 

If my thinking is completely wrong please educate me but If I run water inj with a smaller pre rad vs a pro alloy would I really be losing out or would we have to take some intake measurements to find out?

 

 

My thoughts:-

 

1 - Yes - but it makes sense to double up the cooling rather than replace one with the other. The water cooling could be triggered based on intake temperature to reduce the need for carrying water around on a day-to-day basis?

 

2- I guess it's the laminova's that are the weak point in the system here and the pro-alloy is over specced compared to the amount of heat the laminova's can actually remove so smaller pre-rad is a realistic option.

 

I have NO data or experience to base this on - it's just my assesment based on what I've read so far. Data logging of intake air temperature and water temperature pre/post laminova's would be nice to see.

[Ormes]

I know this isn't a turbo thread but anyone know what temp turbo retards ignition at? Cheers

[ufods]

....not exactly but around 56 Grad