Here are the logic settings. Pretty straight forward once you wire up the FIdle circuit to complete a ground (our cars don't need fast idle because the warm-up idle is set by the drive-by-wire on the factory ECU) and then wire the clutch to the FIdle wire on the harness through the relay i have diagramed in the last post.
Megasquirt controlling the supercharger clutch control...
I modified the Megasquirt and wired up a relay to kick on my supercharger using spare port logic on the MS2, so I'm bypassing the factory ECU control to the supercharger clutch entirely. In doing this, I learned a few things about the supercharger clutch that I did not know before. The clutch isn't "on or off" it's actually a pulsed negative signal, similar to how fuel injectors are controlled. Which means it's not completely engaged at lower RPM's, it's pulsed. Then at a higher RPM it's fully engaged. It implies this in the service manual, but it never really dawned on me what that meant until I wired it up to full. At first I set my control logic to anything greater than 2% throttle... that way when I let off the gas pedal it disengages the clutch, and when I give it any gas it's engaged all the time. Holy hell... NOT recommended. I can't control this damn thing, it's so unbelievably touchy. I can't "ease onto the throttle" - it's simply not an option. At 1000rpm's I'm boosting and losing traction no matter how little I give it. On one hand... it's kind of scary, but on the other, it's fun as hell. The launches are incredible once I can get traction. So I've been messing with some settings. I changed it to where the throttle has to be greater than 10% and the rpm's above 1100rpm. It's a lot more controllable now, but I'm still trying to find a happy medium.
boy, those words you just posted are GOLD to me... you got P.M!!!
Last week was a busy week for me on the car. I pulled the engine to fix my exhaust leaks. I also had a coolant leak on the water pump, so I replaced the factory rubber seal with a thick layer of RTV. Pulled the headers off and put thicker composite graphite gaskets in place. Next few posts will be the pics...
After getting the headers off, and taking the factory gaskets off, I found the exhaust leaks! Two of the gaskets were blown to bits. This is probably from the header tubes being much larger than stock.
Next pic shows the gaskets I found to attempt to replace the factory ones. They are larger in the center (2" to match my pipes) and they're 3 layer composite graphite, a lot thicker, should seal a LOT better. I couldn't find an exact size, so I had to modify them a bit, move the holes closer to the center and cut a corner off to clear the top of the head. The top row is the before and bottom row is the after.
Water pump removal...
I've gotta say... nothing is hotter than seeing a chick work on a car. It even beats watching a girl play guitar. So when my girlfriend came out excited that I was working on my car and was like "oooh, i wanna help, what are you doing?" and I let her remove my water pump... well... I couldn't resist taking pictures even though she made it clear she didn't want any photos while she was dressed in her "garage clothes"! haha, girls...
Anyways, after it was off, I cleaned it with a wire brush and the RTV sealed it right up.
She's going to hate me for posting this by the way.
And since the crank pulley is off anyways, I thought I'd take better pictures of it, and the trigger wheel, and the bracket that holds them together. Notice the bracket is designed to have the bolt go through the center to tighten it, and this allows me to make adjustments simply by loosening the bolt... rotating the trigger wheel where I need it... and then tightening it back up again.
(And just as a refresher from my previous posts, the trigger wheel is for my EDIS system, to control spark and RPM signal on my MSII ECU.)
After getting the headers off, and taking the factory gaskets off, I found the exhaust leaks! Two of the gaskets were blown to bits. This is probably from the header tubes being much larger than stock.
Next pic shows the gaskets I found to attempt to replace the factory ones. They are larger in the center (2" to match my pipes) and they're 3 layer composite graphite, a lot thicker, should seal a LOT better. I couldn't find an exact size, so I had to modify them a bit, move the holes closer to the center and cut a corner off to clear the top of the head. The top row is the before and bottom row is the after.
And the last pics show how they fit.
Wow, those are thin exaust flanges. I would be a bit concerned with both cracking and continued exhaust leaks - regardless of gasket material.
Looking forward to seeing you complete the project and seeing some numbers.
Wow, those are thin exaust flanges. I would be a bit concerned with both cracking and continued exhaust leaks - regardless of gasket material.
Those were my thoughts from the beginning, and I think you're right. I haven't really been able to tell yet, but we'll see. I brought this point up to the guy that built them before last week, letting him know I was going to be removing them to fix a leak, and he said welding a larger flange is possible but he wouldn't be able to get to it for a while. So I went ahead with the new gaskets instead. I'm a bit skeptical, but we'll see I guess. I guess the old adage holds true, if you want something done right you've gotta do it yourself... now on to learning how to weld!
My turbo project is most likely going forward in June. I'm still purchasing stuff for it, and have quite a bit of stuff left that I still need to get. I already decided on a turbo, based on lots of research, and decided to go with a Holset VGT turbo, and if you haven't read up on VGT technology you should check it out, it's very efficient (Note: this is different than VNT, and holset uses a different VGT technology than Garrett). And it's perfect for a rear-mount application due to the electronics' sensitivity to heat, which is drastically less on a rear mount application. I purchased it a few weeks ago, and will post pictures soon... although it will be more like a teaser pic since I won't be ready to install it for a few months. Anyways, I guess the point of all this was, when I do the turbo I will probably install the larger flanges at the same time, whether the current ones are getting the job done or not.
Its good to see you do your own work
Reminds me of earlier days modding everything in sight... hmm still do a bit
I agree on the flanges, sadly I think the same issue will reoccur. Did you keep a copy of the gasket shape? would allow some laser cut flanges to be made ready to weld on.
I like ceramic (Jet hot etc) exhaust coatings better than the insulating cloth. Ive had issues with corrosion under that stuff.
On the water pump, doesnt it use a ribbed O ring type seal? I am suspect of using rtv (silicon) type sealers unless VERY sparingly as when you bolt down it all squeezes out no matter how thin and puts lumps and worms into the cooling system and blocks radiator cores
I agree on the flanges, sadly I think the same issue will reoccur. Did you keep a copy of the gasket shape? would allow some laser cut flanges to be made ready to weld on.
I like ceramic (Jet hot etc) exhaust coatings better than the insulating cloth. Ive had issues with corrosion under that stuff.
I haven't kept a shape of the gaskets, but I will probably end up using a shape based on the factory gaskets again, but much thicker! And of course the center hole the size of the tubes.
Yeah, I like the other coatings as well, I used the VHT ceramic coat (spray can) and it helps protect from corrosion and rusting "somewhat" (I added "somewhat" after realilzing it chips easy over time) so I will have to sand blast them and send them in for non-spray-can coating when I change the flanges.
Quote:
Originally Posted by Bazzle
On the water pump, doesnt it use a ribbed O ring type seal? I am suspect of using rtv (silicon) type sealers unless VERY sparingly as when you bolt down it all squeezes out no matter how thin and puts lumps and worms into the cooling system and blocks radiator cores
You are correct. Actually it's just a flat ring, not ribbed. The problem was (my best guess) is last time I popped the water pump off (to remove the engine front cover) I didn't use a new seal (went with the "eh, this looks ok to me" approach) and I guess it was comprimised somehow and didn't provide a good seal. I heard from other non-MB owners that a lot of other makes have bad water pump seals to begin with, and they've had trouble with them new or not... so I just did what they recommended with the RTV. The reason I had to use a lot was to fill the inset tract that the rubber gasket sat inside. It ended up being pretty uniform, and not spilling over the edges too bad, not more than normal anyways. I'm hoping to not have any trouble with my cooling system! Should be ok though.
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