968 Supercharger Kit Development
#1188
Track Day
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The 7-rib VW Phaeton belt should fit the standard crank pulley and SC pulley set-up. To get this to fit the larger crank pulley set-up, we will drop the top idler to a 70mm diamteter grooved idler to decrease the overall belt length required. This will also have the added benefit of reducing the bending moment applied to the canterlevered support bar from the belt.
If there is a problem with the overall length of the 1560mm belt being too short - there are many top idler pulley options to reduce the overall wrap/length on the idler.
This is not yet a proven solution, nor do we know what sort of boost levels we will get. hopefully a couple of weeks will tell.
If there is a problem with the overall length of the 1560mm belt being too short - there are many top idler pulley options to reduce the overall wrap/length on the idler.
This is not yet a proven solution, nor do we know what sort of boost levels we will get. hopefully a couple of weeks will tell.
#1190
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Supercharger is back from Raptor today with mods done. Belt went in an overnight bag to Melbourne yesterday (but will most likely get there tomorrow), one rib will be sheared off and then sent back. Hopefully everything back together and ready to tune end of next week.
#1191
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I`m also getting a step closer. Got the grooved drive pulley machined and grooved idler puley.
Cut the 7th rib off the belt myself, quite straightforward with a long straight edge and clamps.
See what this goes like with standard crank drive and 55mm pulley.
May start getting fuel issues, but I have the uprated injectors from the origional S2 kit, so maybe now I will get to use them
Cut the 7th rib off the belt myself, quite straightforward with a long straight edge and clamps.
See what this goes like with standard crank drive and 55mm pulley.
May start getting fuel issues, but I have the uprated injectors from the origional S2 kit, so maybe now I will get to use them
#1192
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Edz, the fuel issue will depend on whether or not you are using the rising rate regulator. I am running an aftermarket ECU and custom tune, but when running the initial crank pulley and stock SC pulley - the larger S2 injectors leaned out at high rpm and we had to go another size higher.
#1193
Nordschleife Master
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You might want to consider a high pressure fuel pump, the Welbro 392 is a great option and costs less than half of the high pressure bosch (044 IIRC) that most turbo guys run. Specs are almost identical.
#1195
Three Wheelin'
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Savass - no concerns about fuel washing down the cylinders, for the following reasons:
1) we normally are at 12.4 to 1 for almost the whole time under load and boost. We touch into 11.8 to 1 only at 6700 rpm. Pretty rare that you go there.
2) fuel washdown requires incomplete or no combustion. We record no such thing, there are no misfires, and the fuel is being consumed.
3) fuel washdown starts to become an issue below 10:1 AF ratio - and you can see the belching black soot out the tailpipe at that AF level.
1) we normally are at 12.4 to 1 for almost the whole time under load and boost. We touch into 11.8 to 1 only at 6700 rpm. Pretty rare that you go there.
2) fuel washdown requires incomplete or no combustion. We record no such thing, there are no misfires, and the fuel is being consumed.
3) fuel washdown starts to become an issue below 10:1 AF ratio - and you can see the belching black soot out the tailpipe at that AF level.
I have advice from other tuners that a desired AFR for a high comp supercharged engine is 10.5-11 at peak torque to minimise chance of detonation and provide sufficient cooling to valves/cylinder head and also keep exhaust temps down for the cat converter.
Do you think that for a tracked car the AFRs would be better on the rich side? Yes it will slightly reduce power but to the benefit of an additional safety margin.
My current tune is AFR 11.5 at 4500 tapering do 11 at 5000 rpm to rev limit.
Maximum boost on my set up is about 6-6.5psi and intercooled.
#1196
Developer
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Yes - generally speaking we tune to 10.5:1 to 10.8:1 for safety in high boost or high compression motors.
That surrenders about 15 HP from the "ideal" HP producing level with gasoline of 12.5:1 AFR.
The problem with setting the engine to 12.5:1 is that very few intake manifolds feed all the cylinders the same, there are small dfifferences in injectors, then the combustion chamber shape and piston crown take effect in the equation - modifying the flame front as it passes, the length and location of the spark plug, etc.
So we opt (as your tuners are telling you) to be on the safe side between 10.5:1 and 11:1.
Below 10:1 you will see diesel-like black smoke out the tailpipe and there is no reason to be there.
That surrenders about 15 HP from the "ideal" HP producing level with gasoline of 12.5:1 AFR.
The problem with setting the engine to 12.5:1 is that very few intake manifolds feed all the cylinders the same, there are small dfifferences in injectors, then the combustion chamber shape and piston crown take effect in the equation - modifying the flame front as it passes, the length and location of the spark plug, etc.
So we opt (as your tuners are telling you) to be on the safe side between 10.5:1 and 11:1.
Below 10:1 you will see diesel-like black smoke out the tailpipe and there is no reason to be there.
#1197
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A quick rummage around the inter-nets suggests this part number for the 7 rib belt:
7PKD1560
This site has it, as do other European parts shops but offhand I do not know if any ship to the USA.
http://www.thehappymotorist.co.uk/fa...2.php?vid=2525
I found a place that does ship but does not list the part on their website. Inquiring...
7PKD1560
This site has it, as do other European parts shops but offhand I do not know if any ship to the USA.
http://www.thehappymotorist.co.uk/fa...2.php?vid=2525
I found a place that does ship but does not list the part on their website. Inquiring...
#1198
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Jfrahm - the part you are quoting is a non-OE part for the VW application. Given the application is a European VW Phaeton (and most of the sites selling the non-OE part are in Russia), plus I wanted it quickly - I bought a VW OE one.
THere was a Goodyear non-OE part and another belt manufacturer who made one (but the other one was 1558 long - so 2mm shorter).
I talked to the Goodyear distributor in Australia and he could not get one Worldwide.
THere was a Goodyear non-OE part and another belt manufacturer who made one (but the other one was 1558 long - so 2mm shorter).
I talked to the Goodyear distributor in Australia and he could not get one Worldwide.