Megasquirt Support Forum (MSEXTRA)

I'm using an E39 M5 pressure plate with a 6-puck cerametallic clutch. It's possible that I'm over 500ft-lbs, but I really just don't think the E39 M5 clutch is up for that or even close to it really. Even with the very aggressive clutch plate, mine is giving up the ghost. One of the mods on the BF.c E39 forum has a twin disc fancy clutch that was over two grand, and his slipped a little bit at the big end of the drag strip. He's at about 500ft-lbs.

Here's my recent .MSQ in case it can be of help. This is on E85, and it's behaving very well other than one little brief misfire that happens for a moment AFTER I make a lot of boost.

Two things:

1) I ordered a stage 5 clutch, lol.

2) I also just bought two M60b40s in very rough shape, and I'm contemplating building an M60b44 over the winter. I'm predictably having a little trouble nailing down the sensor types for the M60b40 though. It seems to me that they are probably both VR sensors even though they have three pins. Am I wrong?

Tjabo wrote:Two things:

1) I ordered a stage 5 clutch, lol.

2) I also just bought two M60b40s in very rough shape, and I'm contemplating building an M60b44 over the winter. I'm predictably having a little trouble nailing down the sensor types for the M60b40 though. It seems to me that they are probably both VR sensors even though they have three pins. Am I wrong?

Nice! What clutch did you get?

The b44 build raises compression to like 11 or 11.5:1 I think. Something to be aware of. But yes, the b40 crank and cam sensors are both VR


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https://youtu.be/e_I7KhtEVHY

^latest YouTube update has some boost noises


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Thanks for the info on the sensors, and nice video!

I ordered a Clutchnet Stage 5 combo, which consists of their Red pressure plate and their 6-puck clutch disc. They claim the buttons on my eBay 6-puck clutch disc are made with inferior crap that renders them a very low coefficient of friction. If that is true, it's possible that I could have gotten away with just their clutch disc and continued to run my E39 M5 pressure plate. BUT, self-adjusting pressure plates are a big pain, and I want to just have enough clutch to make as much power as I can, so I bought the combo.

Regarding the M60b44, the compression ratio figures I've been seeing for them have been around 10.9:1. I think any of these compression ratios might be okay with significant boost since I'm running E85.... Alternatively though, I might build an "M60b42", using the M60 heads, cams and crank, with the M62 block, rods and pistons. I have to do some calculations and see what the compression ration would come out to though before I decide for sure. Dunno..

Tjabo wrote:Thanks for the info on the sensors, and nice video!

I ordered a Clutchnet Stage 5 combo, which consists of their Red pressure plate and their 6-puck clutch disc. They claim the buttons on my eBay 6-puck clutch disc are made with inferior crap that renders them a very low coefficient of friction. If that is true, it's possible that I could have gotten away with just their clutch disc and continued to run my E39 M5 pressure plate. BUT, self-adjusting pressure plates are a big pain, and I want to just have enough clutch to make as much power as I can, so I bought the combo.

Regarding the M60b44, the compression ratio figures I've been seeing for them have been around 10.9:1. I think any of these compression ratios might be okay with significant boost since I'm running E85.... Alternatively though, I might build an "M60b42", using the M60 heads, cams and crank, with the M62 block, rods and pistons. I have to do some calculations and see what the compression ration would come out to though before I decide for sure. Dunno..

Nice, I may look into them. Ya the self adjusting PP is a pain. You can use an e46 m3 clutch, but I tried the pressure plate and the dowels wouldn’t line up. I’m sure it *could* work with a little finessing. But I’ll cross that bridge when I get there.

Right now I keep blowing off charge piping at the throttle body, need to grind down the ASC throttle body mounting point so I can slide a couple me further on.

If you want to get really crazy, I’ve looked into the possibility of using a 4.6is bottom with b40 heads, I’m like 85% sure it would work, but you’d run into a similar compression number, if not higher. And at that point just use the whole 4.6. And at that point just get a 4.8. And at thaaattt point just get a new 550. Haha


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You E34 guys have a much better situation for clutches than we E39ers. We have a 9.5" clutch compared to your 10.5" I guess, because we have the 60-2 wheel around the perimeter of the flywheel. Consequently, our options are more limited, and our clutches don't work as well I guess.

Regarding your coupler problem, what I have done is actually use the ASC elbow as my first bend out of the throttle body, with a slightly thicker than factory O-ring on the TB. It solidifies that issue you are experiencing, plus provides a way to firmly hold the IAC in place:

Well, that is the 2nd generation, that only really uses the ASC elbow flange, but still..

The other good option is to weld a bead around the end of the TB, or even just rough it up and make a "bead" around it with JB Weld. A guy on LS1Tech has made that work with a LOT of boost.

Ok, here was the first version that used more of the ASC elbow:

I’m actually using an e39 setup. Haha. JBR flywheel and oem m5 clutch, but all e39 specs.

What are you doing about the PCV system? Im getting a block off plate from that guy Gregg on BFc.


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abeebe718 wrote:What are you doing about the PCV system? Im getting a block off plate from that guy Gregg on BFc.

I made one. I had been talking to Greg about one, but our schedules didn't coincide. This one took me about a half hour I guess:



Even has one unused 3/8"NPT hole with a plug in it in case I forgot something, haha...

New Year update: Car is running really well. Been driving it nearly daily now. Switched to closed loop idle and will never go back. I can now just bump the key and it fires up and idles every time. Fixed a boost leak and got some new vibrant couplers that hold very well. Got an Aeromotive 340lph e85 pump ready to go in. Still only at about 4psi, but planning to start turning it up soon.

The only issue I'm having is that I'm getting lean spikes (17-19 afr) when I first crack the throttle after decel. But it only seems to happen at cruising rpms. On hard pulls it's fine, but let's say I'm just cruising through my neighborhood in second gear around 2k rpms, lift off for a moment, then ease back into it, it spikes momentarily. I'm not horribly concerned because its such a low load scenario, but seeing that high a number on the wideband is always concerning. Any tips on how to overcome this? I've tried adding a little fuel in the cells where it's happening, but no real effect. I'm thinking maybe the BOV spring is too stiff so I'm getting just enough charged air buildup, even though it's not in boost, that it floods the intake enough to cause the spike?

My guess is that if you posted your current .MSQ with a log of the problem, someone on here could give you a pretty good idea how to tune that out.

If you log the lean spikes could you not then use the Accel Enrichment to dial it out.

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MegaMicra wrote:If you log the lean spikes could you not then use the Accel Enrichment to dial it out.

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Admittedly I haven't logged the issue yet, was sort of looking for preliminary advice. I don't think it's an accel enrichment issue, because it doen't happen if i'm cruising at a constant throttle %, then accelerate. Only immediately after decel, when I first touch the throttle. Will post a log soon though.

Tjabo wrote:My guess is that if you posted your current .MSQ with a log of the problem, someone on here could give you a pretty good idea how to tune that out.

Ya once all this snow/ice melts (lol wtf south carolina) and i can go drive around I'll log it.

Here's a 2-3 pull. You can see the lean spike right when i get back in to it. It's worse at low speeds, like just in my neighborhood, but I forgot to datalog when i pulled back in.

I'm not sure if it's what is keeping people from commenting on this situation, but normally it's expected that you post your applicable .MSQ file along with your log. That way people can open them both up in MLV and see where the indicator is going in your tables when the trouble happens.

Tjabo wrote:I'm not sure if it's what is keeping people from commenting on this situation, but normally it's expected that you post your applicable .MSQ file along with your log. That way people can open them both up in MLV and see where the indicator is going in your tables when the trouble happens.

Ah, well, ya that would probably help. Haha. Will post that tonight

Here's the MSQ

You log shows this happening between ~100-150 TPSdot and your MSQ shows the threshold at 200T PSdot. So you're not doing any AE.

I like Andy Whittle's youtube video on AE on youtube. I haven't used the method yet but it looks good, easy.