Southways

To my knowledge, Magnuson has not made an aftermarket supercharger with a clutch. Please send me a photo of your system as I am keen to learn more.

Jack_88

Ah, my mistake. It's a bypass valve. I was ill informed. However, the end result is the same. Surge of power, sometimes when I don't want it. It makes cruise control on the freeway strange as well. A mild incline can cause enough throttle input to cause the supercharger to kick in, giving more power than necessary and overshooting the set speed. It coasts back down, and keeps cycling through this pattern until I'm done with the incline. It also frequently exhibits driveability issues when cold for the first 5 minutes or so, feeling gutless until the blower kicks in and even so, not the same as when warm. I just drive like an old lady until it gets up to temp. Shouldn't be pushed while cold anyway, so it doesn't really impede my fun, just irritating.

tusabes

Sounds like there's something wrong with your supercharger system , it should not feel like that at all

Jack_88

The cold running issue is in fact not the way it should be, but I've been back and forth with what is supposed to be the best tuner on the eastern seaboard quite a bit with data logs, and they haven't been able to solve it. I've since given up, since even after driving it down to them, they couldn't figure it out.

The rest is in fact normal operation, so I'm told. The cruise control surge isn't particularly obvious, few even notice. The blower is designed to freewheel when the engine is under light load, so it's engagement would always mean a sudden bump in power, whatever speed you're at. How noticeable it is depends on what gear you're in. When taking off hard from a standstill, you never notice it kick on. I'm not done looking into it, though.

ZephTheChef

There is a guy that runs a shop that specializes in supercharger porting, he works primarily with the GT500s and Lightnings, and his comments were the same about the Kenne Bell kit on his truck (which I believe is a whipple supercharger). I don't know if he ever ended up getting anything figured out, but really, it shouldn't be that way. The bypass valve operation on my TVS2300 eaton is very smooth and predictable. It's just like driving a naturally aspirated car with like 3x the power, lol. Here is his thread on it, I don't know if it will help you out or not but you may want to contact him directly and see if he ever came up with a solution.

http://www.thechicagogarage.com/foru...s-welcome.html

And a link to his FB page for the business:

https://www.facebook.com/jokerzperformance/?fref=ts

Jack_88

It sounds like he was having exactly the same issue, but on a different brand blower. Thanks for that, I'll give him an ask and see what he says.

ZephTheChef

I believe Magnuson just provides a custom case and the rest of the kit but the actual SC is generally a whipple or an eaton TVS rotor pack. So he may have been dealing with a very similar if not identical setup as far as the guts goes.

Jack_88

TVS2300 guts, you are correct. There should be a solution, but I'm not experienced enough to know where to start.

ZephTheChef

Interesting. I was under the impression the problem was more with the whipple/twin screw version. I wonder if the bypass valve itself is a different size or if it's juat in the actuation of it. I think your options are either adding an auxiliary bypass valve if the issue is sizing of that, or changing the actuator to one with different response characteristics, OR modifying the air pressure signal to the actuator... potentially by adding a vacuum reservoir of sorts that would take longer to equalize to SC inlet pressure to intentionally cause lag at lower throttle opening. Dunno how well that would work. I have no complaints about my TVS.

It almost sounds like your issue may be more similar to my issues in turbo only mode. It's like going from no power and having to use 40-50% throttle for decent acceleration to going almost instantly to 28psi when it spools. For me, having the instant boost from the SC available at lower throttle openings and rpm makes it so much more predictable and pleasant. The issue might actually be that the SC actuation just has so little preload that it goes from wide open to shut as soon as it hits the tipping point pressure-wise, where the factory eaton actuator has progressive travel based on level of vacuum present. However, I've found even with the actuator disconnected for full-time SC operation it isn't difficult to drive. Inlet pressure then dictates outlet pressure so anything less than 11% throttle produces no boost, 11% is the tipping point to positive slight boost whereas it takes about 25% to actually hit max boost. This is with a 170mm oval monoblade TB, so a smaller TB should have even greater resolution.

ZephTheChef

In other words, you might try wiring the bypass shut just for grins and see if it's more controllable with full-time boost and just controlling SC inlet pressure with your right foot. I think it may be the sudden transition that is problematic for you, not the boost itself. I'm not thoroughly convinced a bypass is even necessary for a non-twincharged application...I am quite sure the blower drive requirements are very small with low inlet pressures.

Jack_88

I've got some looking to do, I see. The guy with the truck gave me some things to check on.

So, anybody have experience with Kleeman on their V12's?

Southways

The plot thickens...

The bypass valve should have a small metal insert on the vacuum nipple (where the hose connects), and the size of the hole in the nipple can significantly affect the light-load transition & modulation. There are also different spring rates available in the valve but I do not know what is in the supercharger you have.
The size of the hole needs to be matched to the tune as there are typically fields in the tune file for the thresholds of throttle plate modulation.

The TVS is an air pump, not a compressor ... which is one of the reasons they run cooler than a twin-screw. The bypass enables the supercharger to "free-wheel" when not needed, unlike the twin-screw that is always compressing & therefore always under load. (Don't be misled by twin-screw marketing BS). Unless just testing, do not wire the bypass shut. The result is likely to be catastrophic to the supercharger & engine (supercharger oil overheating, engine burning valves/pistons).

Jack_88

Good to know, I'll have to look and see what I've got. It would be nice if the uptake on the blower could be slowed up a bit on mid throttle.

ZephTheChef

Good watching out with respect to the bypass valve...I often forget when giving advice that not everyone will understand the implications of doing something and make the necessary tuning adjustments or precautions. I can't see it causing any harm to tbe supercharger, but the increased cylinder pressure at lower throttle positions could certainly be wildly inappropriate for the air fuel ratios and timing advance that may be otherwise employed.

Jack_88

Well, I've ordered the kit from Kleeman. I'm excited to see how the car responds. I'll let you guys know.

ZephTheChef

Doing both ECU and trans tune?

Jack_88

Yep. I don't want the torque limiter spoiling the party. I figured I may as well go ahead since the car is laid up waiting for the selector lever to come in.

ZephTheChef

Yeah, that limiter is a huge pain. Kinda scary when it hits too.

Jack_88

I had no idea how to take out the ECU and TCU when I ordered the tune. It took 5 minutes, I was amazed at how easy something in this car was for once. I hope that my key was stuck in the ignition didn't matter. It's been there for the past day and it seemed like everything in the car was asleep when I disconnected the battery before removing the modules. Now tomorrow I have to ship everything off. Let's see what I get here first, my freshly tuned modules or the shift selector lever.

Jack_88

Well, Kleeman called today and everything was done and packed up by noon. The down side is they told me my TCU had a bunch of transmission oil in it. Trying to drain the fluid resulted in a stripped drain plug, so I just took the pan off while it was full of fluid. It had 4 quarts come out of it. I've been spraying the connectors with non-chlorinated brake cleaner to irrigate the wires, as per instructions. The computers should arrive tomorrow. I'll have the console the rest of the way together from fixing the stuck in park issue as well. Further reporting to follow.

tusabes

Make sure to replace the transmission electrical plug before you put in your new parts
As that is the reason your tcu filled with oil

The How to video is in the first post here
https://mbworld.org/forums/s-class-w...ir-videos.html

Jack_88

Yep, that was already a part I had, intending to replace it proactively. Turns out it's too late to be proactive. At least there was no apparent problem before it was found.

Jack_88

Got the back together and running, it seems as fat and happy as ever. I drove conservatively for about 10-15 minutes before giving it a good kick in the pants. On the freeway, it seems to have a bit of extra oomph, reaching triple digits without any effort, and it seems to have a little bit of extra snarl at the top end, and unless my eyes deceive me, it seems to have a new slightly extended redline. Coming from a standstill, the traction control works hard and the car positively launches as if from a cannon. Much more so than before. Transmission is as smooth as ever, whether you're going cruising or giving it heck. Well worth the $1500.