A Gambler’s Thread – e30mclow’s Replacement S4

[funkin]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

looking deadly!

[e30mclow]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Had a few hours yesterday evening, and managed to get the car up and running.

Started right up and sounds great!

One issue has arisen though, regarding boost control.

- Vacuum at idle is strong, at 18-19Hg
- N75 Unplugged, she cracks bang on 8psi
- Issue -> the car is over boosting right up to an indicated 30psi on the Podi gauge
- No CEL
- No Codes

I presume it is either an issue with my N75 sticking, or my MAP sensor?

Ran out of time, but will run some logs of things like Desired Boost vs Actual vs WG Duty Cycle. I'm just a little nervous of doing so given how high she's boosting.
It is my understanding that the N75 merely regulates boost according to the desired boost signal vs actual. So if I'm not getting a Boost Deviation code having gone all the way to 30psi vs desired 19-21psi, I assume it is more likely an issue with the MAP confusing things?

Anyway, I'll get it plugged in tonight and log a few WOT runs just until she spikes @ 30psi then get off it asap.

[bobkatkat]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Have you MightyVac'd the N75 lines? Seems like you may have a torn/loose WG line or maybe two.

[e30mclow]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

I'll have a look. I figured with it showing 18-19Hg @ idle would have meant that they were OK?

I bought a MightVac back when we were trying to figure out the Imola. Unfortunately for me it only does vac, unlike your one which if I remember correctly did both.

[bobkatkat]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Ya my mightyvac does both. I also am currently boosting to 30psi with two torn lines and a rock solid 20hg.

[e30mclow]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Can you check something for me? No rush though...

If you pop off the hose on the driver's side of your N75 and blow into it, does it hold air?
Seemingly that is the easiest way to verify the lines are in tact. I replaced one of the lines, and inspected the other before putting the engine in, so I'm confused.

I'll know more once I get home from work.

[e30mclow]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Has to be my N75. The one in the black car went several months ago, and the high mileage one from the Imola was popped in to keep things moving.
Ordered one with expedited overnight shipping, so hopefully that fixes things and I can work with a guy on AZ to start tuning.

Going full retard with Rolling Anti-Lad, NLAS, Brake Boosting and Launch Control. I are the most maturest 32 year old.

[e30mclow]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Well, after all of that, it wasn't the N75. Must be the tune
Running it at WG cracking pressure for now, while I await a Bosch 044 pump to try and counter my lean issues under boost.

Once the stronger pump is in, I'll use a revised base file to start from scratch.

[e30mclow]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Sooooooo apparently the wires on a Bosch 044 are reversed vs that of the OEM pump???
Found that out after inhaling gas for an hour last night. My head is banging today.

Anyway, it ain't running so I'll need to spend time at it tonight.

General photo comparative of OEM vs Bosch:

[Ponto]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Dang thats some awesome work.

[e30mclow]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Got the wiring figured out, so she's now running.
I'm getting no codes which is great.

Base tune is going on tonight, then hopefully some logging & revisions once I figure out where I can drive without getting a ticket.

[Canadian Turbo]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Glad you are getting there!!!

[e30mclow]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

B5-ness occurring here in the last few days.
Evidently I have blown the new wastegate line going to the passenger side turbo.

Wouldn't you know it has blown down where the sun doesn't shine, meaning I need to remove:
- Front Sway Bar
- Pass. Engine Mount
- Pass. Engine Mount Bracket
- Pass. Inlet

then wriggle a replacement up in there somehow.

I'll firstly attempt to run a temporary line down there somehow and just abandon the one that is on it. That way I can absolutely confirm that this has been my issue, or if the engine needs to come out.

[e30mclow]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

For future reference, this is what I did with the replacement line.

Firstly, stop going to the gym about 2 years before attempting this. You need pencil arms and the flexibility of a cheese string.

Arranged tools in order of requirement, in keeping with the scatter plot method.




Carefully cut the OEM crimps off without safety glasses and while wearing flip flops


Replaced both line with new silicone high pressure lines


Put a piece of steel wire on the end to help push the flaccid silicone hose up through the back of the block.


Finally in a position to start logging and getting back to some sort of power.
My 2 Step, NLS and Brake Boosting are operational now though

Going to drive out to the middle of nowhere tonight and get some decent 3rd gear logs.
So far, the car just isn't as fast as the Imola was. I'm not sure if this is due to the 85% humidity and 30c weather here.

[Ur0Drivr]

Re: A Gambler’s Thread – e30mclow’s Replacement S4

Hahaha!! Nice writeup Gerard