Northern's Sterlingsilber M52 Turbo 325is

[Northern]

Might need to open this pic in a new tab for it to show a decent resolution...

[Northern]

Not much going on with this car. Drove it a bit but I have no reason to leave the house.

Still trying to get the MAP working.
wideband O2 sensor died again, so I warrantied it but have yet to install the new one.


Pulled out Ye Olde Fender Roller to try to lower the car down again. I don't know if it made much of a difference, but it let me lower the car an inch or so.



Also lets me take pictures at utter degenerate levels of stance



I bought this kit for the S2.93 I'm building. I honestly though there would be more to it for $100. Would not recommend, just buy everything separately.
Hell, you don't even need the axle clips and I don't know why there are two cover gaskets.



MAP progression. Bought a third sensor, AC Delco 4bar for some LS variant. It also has a bosch part number.
It's supposed to mount to a flange, so I had to adapt it for a hose barb.





Much smaller than the old one. Probably will reuse the old one on the other car, since I think the issue is from trying to use the post cat O2 ground.



Really want to be able to log MAP because my EBC just flashes "CUT" over 10psi and it seems that the 7.5psi spring wants to live somewhere north of 10psi.

I reenabled VANOS and load comes up faster. I have the modifier tables changing fueling/timing much less than stock.

Engine seems happy with a bottle of VP Octanium per 35L of fuel. Hitting a hair above double the stock load numbers (since the MAF and Load in this graph are half the true number), but since this is a different MAF, something could be off.

[Northern]

Been a while since last update, nothing crazy to report.

started running VP Octanium octane booster with my crappy 91 AKI gas and it seems to have a good effect on knock.
I'm not sure how quickly the octane rating decays as the car sits, but I had zero knock under boost for the first few weeks and now I'm up to 1 degree at times.
Might be something else, but I think for this specific application, this specific octane booster does work.

I've been trying to diagnose a clunk in the rear, seems to be from one side of the back. I went under and checked everything a few times and I found the subframe mounts were loose? I managed to get 2+ turns before I reached spec. They're garagistic riser mounts FWIW, not sure if they deform over time or if I simply forgot to torque them last time I installed the subframe.
The driveshaft (or trans?) also seems to have some sort of play, but I don't want to drop exhaust/heat shields to mess with it right now.

Other than that, I found nothing wrong back there other than that my rear Koni Sports (top adjust mustang) had un-adjusted themselves? I only checked that because the rear seemed bouncy.
I set them both to 1 turn from full soft and it's much less bouncy now, but I might try another 0.5 turns and see how it goes.


Here's an engine bay pic because it's been a while

[Northern]

yes, at least 12 pops and 3 bangs.

I will share them with all the kids who post "pls gib popcorn tuen" on romraider, so that they can go on to drive noise legislation in a more restrictive direction in their locale.

[ba114]

loving the build! will you have hectic pops & bangs when you're done? :P

[Northern]

Used my gopro for the first time in years. Here's a quick 1 minute video with an engine bay mic:
(also I'm still overboosting to ~11psi...)

https://youtu.be/tJzrilZ7d7Q

[Northern]

^ does an M52 reach atmospheric at WOT in NA form?

Definitely an optimistic number either way.

[varg]

Yeah, seems pretty high. Quick estimate; saw a dyno of an M52B28 with M50 manifold and a tune and it was 196whp, 7psi of boost so 1.48 atmospheres of manifold pressure; 290whp/322hp. Drivetrain loss estimated by typical stock M20 dyno numbers (150whp) at ~11%.

[Northern]

Dont forget to multiply this by 0.8-0.85 to take into account drivetrain losses

It's saying 395hp@6509 and 325 ftlb @ 5800.
at 0.8 that's still 316whp, but I'm just skeptical of it adding that much from just 7psi.

[ba114]

...I also made a calculated column in megalogviewerHD for estimated HP based on MAF*0.3472 but it also seems like 25% high....

Dont forget to multiply this by 0.8-0.85 to take into account drivetrain losses

[Northern]

Thanks! I like that I've managed to keep the exterior reasonably stock looking, but I really need to do some bodywork at some point soon...


Small updates:

I made a new spreadsheet to compare timing maps, resulting knock, and update my timing map with the info. I think it has helped me start to dial my timing in.
With the 7.25lb spring, and timing adjustments over the past bit, I'm down to a maximum of 1.5 degrees of timing being pulled at WOT (down from like 7 at one point)

Car pulls nice, drives nice but has a few quirky spots in the fuel map still that I need to work on (Example: If I am idling and continuously stab/release the brake, load jumps up a bit and it goes very lean. My idle point is between 4 cells and I think the lower cells are too rich/the upper cells are too lean, so I'll slowly shift them until it works right.)

I'm curious to know what the car makes for power but it's hard to judge. It topped out at 1002mg/stk load and 1150kg/hr of airflow, which is not quite double a stock M52. I've thrown pulls in virtual dyno but it seems far too optimistic.
I also made a calculated column in megalogviewerHD for estimated HP based on MAF*0.3472 but it also seems like 25% high. I imagine I'm in the 300hp neighborhood just from the ~0.5bar

[zwill23]

I’m in Texas so pretty lawless as far as older vehicles go... I appreciate the feedback! I figure I’ll just run with it and worst case scenario plumb it if need be. It’s pretty nice that you can seem domestic cruising around town without attracting attention. Self control is also a big factor lol.

Digging the evolution of this car, it’s very unsuspecting.

[Northern]

Car sounds great in the tunnel! Would you recommend the open wastegate dump? I have been trying to get mine recirculated but I’ve had three shops give me a hard no now. I’m considering running one, even temporarily so I can get a tune in the car. But then I have concerns about a re-tune after recirculating... the list goes on lol

If it is legal/will pass inspections where you live, I 100% recommend it lol. It sounds absolutely barbaric when the wastegate opens, but if you want to drive around like a normal human, it's nice and quiet. Not sure what the impact on boost levels are, but I know a lot of 24v manifolds have boost creep to some extent and open dump vs recirc might impact that somehow.

Plugs look good to me, colour seems about right for a boosted car, although as you no doubt are aware that only gives an indication of the general tune.
Quite pink on the ceramic, I think that means your fuel has lots of additives, though I'm not 100% on that.

Gas here is notoriously crappy, 91 is the highest octane you can get at any pump and I wouldn't be surprised at all if it was chock full of additives.

[econti]

Plugs look good to me, colour seems about right for a boosted car, although as you no doubt are aware that only gives an indication of the general tune.
Quite pink on the ceramic, I think that means your fuel has lots of additives, though I'm not 100% on that.

[zwill23]

Car sounds great in the tunnel! Would you recommend the open wastegate dump? I have been trying to get mine recirculated but I’ve had three shops give me a hard no now. I’m considering running one, even temporarily so I can get a tune in the car. But then I have concerns about a re-tune after recirculating... the list goes on lol