Anyone know how to read the supercharger bypass valve readings in STAR.
When logged into it for testing to see if it is fully closed I have a reading of 1599 % under full boost. What the hell does that mean ?? LOL
When it's open it shows 1.10%
I seem to remember this being discussed in another thread somewhere. I think that there were two possibilities. One was that the scaling was way off, so the numbers were not directly representative of the opening angle. Second that the percentages were aggregates of several factors in the calculation for the desired angle (or percentage of opening), and then not scaled.
What happens mid throttle? Does it go in a linear fashion from 1599% to 1.10%? I was wondering if the closed position number came from some kind of programming error, where the value is written with too few bits, and the value rolls over, or some bits get chopped at some point.
Sounds strange, but I have certainly seen that at times on other stuff.
I knew it was shut, or should be but was trying to see why I am loosing boost from 4,500 up to red line. Around 1.5lb's lost and not from belt slip.
I have ten data logs on different times of year, temps, conditions and like clock work boost bleeds off so assumed that the valve was opening up for some reason but not sure.
Run a 168-77 combination for pulleys,IAT and knock corrections in tune disabled so no ECU corrections with that.
I sort of did Finny. I put the block off plate in but cut a small hole big enough for the throttle blade to clear so it is about 75% blocked off. Did that because was afraid it would not run correctly completely blocked and I could get the best of both worlds.
Either way it made absolutely no difference and figured it would have to do something so maybe I will block it completely.
I just pulled another data log so I will down load and see where it's at.
I was also screwing around with my Map Clamp thinking maybe it was allowing the ECU to do something funny ???
Does anyone have a data log with higher boost ,15-16lb's, that they can pull up and see what it's doing in the upper rpm ?
Also under boost the readings are staying the same so this is telling me the valve is staying closed according to STAR.
It seems MANY people have the same drop in boost at higher rpm and others do not so it can't be that the blower is running out of steam up top. I am only seeing 16lb's at peak and I have heard they will go as high as 18 ???
OK here is where I am at. Pulled the blower"again" lol and installed the block off plate. Car drives and idles exactly the same so that was great. Under boost it is much more violent meaning boost is instantly there with no control from the bypass. I picked up 1/2 to almost 1lb pound of boost on the top end but now find that the belt is slipping even worse and don't know why. Also boost peaks at 5k instead of 4,500 and holds better through the rpm band. My data logs now shows peaks and valleys of boost where before it would just climb up and then begin to drop off. I believe with out the bypass bleeding boost the load on the blower is much greater and that puts more load on the belt system.May try some stuff called Track Bite on the belt and see what that does but im at a loss right now considering I feel my tensioner and wrap set up is very very good with everything custom plus a Griptech pulley as well. Tensioner is a 30 lb unit as well. Pulley combination is 168-77. Would like the tensioner closer to the pulley but belt combinations that I tried this size fit the best with the most tension.
On a side note without the bypass the superchager has gotten really quiet do to the boost not free flowing through the bypass system...now there is a constant load on the rotors.
I thought that too so I would inspect it often and found nothing as far as metal transfer or scouring-blueing. With the amount of beatings and 1/2 mile passes on the car the backing plate should be smoked big time but still looks great.
There are still signs of belt dust so I know it still slips....enough for my analog boost data log to pick it up on the recording.
I also never had this issue until I installed 3.06 gears and a lighter torque converter that is 10lbs less from stock so the engine comes up much much faster now.
Good info. Thought about the rpm belts but heard some very conflicting information on longevity and breakage if not tensioned correctly.
Will order one tonight and update.
It still baffles me with my set up that there is a lot of slip now especially now with the bypass blocked...I guess the blower is really making more boost early and not bleeding off from torque control.
On a side note boost was much much better with a new belt that was REALLY tight but it still dust all over the bracket.
I haven't seen such info, but I am interested in reading up about it. Any pointers in the right direction are welcome. I always wonder why I see a lot of the green belts in various pics, instead of the RPM belt. Might be a coincidence, or maybe it also has to do with what you are mentioning
I haven't collected data with this belt compared to the other belts, but its holding up nicely in my stock build.
I thought you ran one from your post.
Anyway I will give my input when I test one out......they have come down in price as they used to be real expensive for a belt..$100.00 and up !!
Thanks Finny....flogged the car real hard and that was not an issue at all. Thought of the ESP long before I went down this road and have found that the valve is really an ECU "last resort" of control.
I still can't believe how much the car changed and it is very obvious that the valve was VERY busy with the boost at all levels. It now drives like my old supercharged cars I had that had nothing more than a blow off valve.
On a side note I can start looking at larger inter coolers since there is more room with no valve in place !!
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
I use this belt on my stock build (stock crank pulley and stock supercharger pulley)
