can someone post or point me some picks/links.
looking at ...
shape size. layout, cooling tubes, exploded view, chambers etc...wanna get a feel for opportunities.
Pictures with the SC removed?
Also If AIT's are in the range of 50-60degC - are these measured before or after the SC or cooler?
If before - is it possible to measure afters? That way I can get a feel for eff. of the SC and subsequent improvements.
I'm sure many have gone before me....

Read a lot about circuit seperation, would like to exploit it more.

Curve ball (without hijaking the intent of this thread...) - have people ever sacrificed their aircon and piped it into a SC cooler? Would have to check the capacities - maybe not enough to make an appreciable difference. Not a bad option with the SLK32 though - it is already a convertible after all.

 

Found this in the service manual - but it really isn't "self explanatory".
Like - okay air in the rear....but I cant see the cooler detail
and not sure how the air gets from the discharge of the screws to the plenums....
etc...etc...

 

Okay....so what I can glean from the manual ....
MAF is main instrument, hower SRT/SLK32's have a MAP as well which also inputs to the PCM (Power Control Module). It doesnt say exactly - but I'm assuming the MAP is post compressor taking from the plenums or somewhere.

To investigate - it says I need to remove a couple of items MAF and Plenums.
This would simply be for a MAF clean and curious inspection - so .....
Should I have seal ring and gaskets at the ready "in case they get damaged", or "yes - you will need them - they are one use only items and will get be cactus".

Its a shame the manual simply says - "inpsect and replace if necessary" for a majority of items rather than giving inspection and test procedures.

 

[QUOTE=Billy22Bob;677884]can someone post or point me some picks/links.



CrossfireForum.org - Search Forums

 

The SRT6 does not use a MAF sensor. Only a MAP sensor. The supercharger discharges down in the front area and the air travels backwards through the intercooler and discharging from the rear. You could drill a small hole in the front of the intercooler and epoxy a thermocouple in the air coming directly from the compressor. Compare to the IAT reading to give you the delta.

 

note - I'm trying to decypher my Carsoft 7.4 real time figures from these sensors.



So stock see if I have this correct.

• AIT's are measured pre compressor on that little sensor prior to the SC
• A MAP sensor measures the pressure in the inlet manifold (after the SC)

So what happens next....? I will guess - to see if I'm on track.

• From the AIT and MAP - the ECU calculates an "inferred" air density at the valve port.
• The ECU than calculates a "mass" flow grams/sec based upon displacement (bore x stroke) and density which is reported to the Fuel map.
• The Fuel map relays a grams/sec mass required from the injector - eg: say 1/12th of the air.*

oila!
please correct where applicable please.

other -
*Is this map simply 2 dimensional? temp v AFR? or does the map take into account other inputs?

 

The AIT is post compressor/intercooler. The Crossfire service manual is quite vague on how the fuel system functions. Inputs that are typically used as inputs include; ambient air temp, voltage, battery temp, pedal position, throttle position, O2 sensors, throttle inlet pressure (TIP), MAP and/or MAF. Not all of these apply to the SRT6 or the Crossfire. The inputs are used to calculate what the fuel pulse should be for varying conditions. Timing uses some of the same inputs and also crank and cam position and knock sensors.

 

Okay so done some investigating (photos) and some calcs....these are mainly guess's since I dont have a dashdaq or anything, just what I'm gleaning from the info in other threads.
of course they are very particular - eg: this is for 450cfm intake and 14psi boost (pre cooler). I'm hearing that the MAP is post cooler.

I'm not sure if due to the cooler (which would lower temperature and hence pressure), the charger would simply drive more pressure into the void and hence boost would be retained at 14psi and density would increase. I'm thinking that might be the case - but the figures in the diagram dont reflect this.

The thing I'm trying to narrow in on is the heat heat rejection from the cooler.
One obvious option is of course water injection or another is determine if repiping the Aircon into this is suitable or do we need a bigger AC pump and more R134a. Whilst another is pump previously compressed air (8bar) into the intakes (atmospheric) as a supplement to cool your intake air (but dont think that would work - too much volume required = huge tank). Don't get too alarmed at the idea - the inject nozzles would simply vent out the front of the intakes in any event of a pressurisation.

Interested to hone these figures with people's experiences. Let me know if they need to be represented in alternate units...

 

Does pullng the throttle body SC intake and and plenums off require any replacement gaskets - or simply reuse the old ones (afterall its only air).
Big Job - ie: hour or 2 to dissasemble/reassemble?

 

You should have plenum gaskets handy if you remove the tanks. You can spray the old gaskets with Copper Seal if you're in a pinch. There is no gasket for the TB just a re-usable O-ring.

Edit, not sure if the SLK32 uses a gasket or not for thr TB. Might be a little different from the SRT6.

 

would that allow me to see exactly where the map is and inspect/replace (as required)?

 

some info.....from
Browser Warning

".............
SL55
The most potent supercharged Mercedes is the SL55 AMG. With a 5.4-litre V8 thumping out 350kW and 700Nm (from just 2650 rpm) that should come as no surprise!
The SL55 AMG’s highly efficient Lysholm-type supercharger (manufactured by IHI) features Teflon coated compressor screws and is driven at more than 23,000 rpm at an engine speed of 6500 rpm. At this speed, the blower displaces 1850kg of induction air per hour and generates up to 12 psi of boost pressure. The supercharger is also equipped with an electro-magnetic clutch that is used to switch it on/off depending on rpm and load. A water-to-air intercooler is also used to help achieve that magic 350kW.

SLK32/C32
Using a 3.2-litre V6, these cars apparently use the same Lysholm-type supercharger unit as the SL55. In this application, however, maximum boost is up to 14.6 psi and at maximum engine speed (6220 rpm) the blower is flowing up to 1200kg per hour of induction air. Interestingly, the blower does not engage at engine speeds above 3000 rpm due to the resulting belt stress. Maximum outputs are 260kW and 450Nm of torque.
.............
We believe there are four common sizes in the IHI Lysholm range – these displace 750cc, 1000cc, 1500cc and 1840cc per revolution.
..........."

and this....from another thread....ex 2008/9
"........The OEM SRT6 Supercharger is available from IHI for appx $4K... Product # S105... Intercooler is made by Garrett but not available as aftermarket product. You will need to purchase from Mercedes dealer as a replacement for SLK32 AMG...."

I'm not sure if the Garrett package includes the cooler or just the fornt air:water intercooler - I suspect both.
My tacho has red marks after 6000 not 6220.

 

and I'm looking for something like this for the X-Fire/SLK32
S105
I think the map is correct tho

 

Found some more...
And a procedure.
I'm doing a coolant change 2morrow, so have the opportunity to pull apart, investigate and insulate etc...

quick question - on refil of the coolant reseviour, is there any concern with air locks - I think I read somewhere they are self deleting - simply run for an hour and top up finally.
and.....how do I correctly set the belt tension once back on...?

PS - everyone here tried to sell me demineralised water for the coolant system...had to look extra hard for destilled, but ended up at $25/20L.