JT's M20 Build Thread

[digger]

I have that Massive kit but haven't installed. i chose 2 x 3/4" inch

[JehTehsus]

I have that Massive kit but haven't installed. i chose 2 x 3/4" inch

Are you planning on running it with IS stock sized brakes? If so that makes me feel a little more optimistic. With the way shipping/deliveries are going it is looking like I won't even be able to get on the road for a while here anyway...

[digger]

Are you planning on running it with IS stock sized brakes? If so that makes me feel a little more optimistic. With the way shipping/deliveries are going it is looking like I won't even be able to get on the road for a while here anyway...

i have the Massive 280mm street kit which is the most that fits under the Alpina's. Calipers are Wilwood dynapro 1.5" pistons iirc. Stock rears calipers. I am going to at least try it out i may not like it in which case id just go back to the boostered setup or perhaps shifted slightly. My only reason for doing this is coming up with a better airbox for the ITB.

[JehTehsus]

i have the Massive 280mm street kit which is the most that fits under the Alpina's. Calipers are Wilwood dynapro 1.5" pistons iirc. Stock rears calipers. I am going to at least try it out i may not like it in which case id just go back to the boostered setup or perhaps shifted slightly. My only reason for doing this is coming up with a better airbox for the ITB.

Yeah, I am in a similar boat. Trying to get a bit more space so I can comfortably mount an E85 sensor and fuel filter, never mind all the room the 8AN lines and fittings eat up. That and fully independent braking circuits is nice.

[whodwho]

The fluid ratio of the stock brakes and bigger masters made for a very hard pedal with minimal travel. It probably would be ok for a track car but on the street I was not very comfortable with it especially if I needed to panic stop.

Looks like many the pics are down today, hopefully they were working when you viewed that thread? Photobucket sucks with their bandwidth limitations, I will have to recreate the thread here with re-hosted pics.

[JehTehsus]

The fluid ratio of the stock brakes and bigger masters made for a very hard pedal with minimal travel. It probably would be ok for a track car but on the street I was not very comfortable with it especially if I needed to panic stop.

Looks like many the pics are down today, hopefully they were working when you viewed that thread? Photobucket sucks with their bandwidth limitations, I will have to recreate the thread here with re-hosted pics.

They were all up when I was looking at it earlier - good old photobucket.

I may end up downsizing front cylinder more then. Do you remember what your pedal ration was? I know 6 is probably more ideal for 'feel' (based on some random thing I read on the internet) but I was planning on setting the massive kit up for 7. Maybe I am having trouble wrapping my head around going from single cylinder to dual; if I apply X lbs of force at the pedal with a given ratio and bore size, do I run the numbers for the twin cylinders assuming that force X or do I need to assume % of X (based on balance bar setup)?. Because a quick run of the numbers with a 0.75" bore and 7:1 ratio gives me 1100 PSI out at 70lbs in, which doesn't sound so bad to me (950PSI at 6:1 definitely does not sound nearly as good). That said to get 1100PSI on the 0.625" with the same ratio is a hair under 50lbs, which leaves me thinking - if I apply 70lbs at the pedal, am I getting 35lbs across both cylinders (assuming 50/50 balance)? Thinking back to free body diagrams, I think yes, but I write software for a living and dropped out of uni so all my mech E friends could make fun of me. So lets say I bias balance bar to get equivalent brake cylinder pressure (which in itself may not be ideal, realistically I probably want a bit more at the fronts, which means these numbers should be worse than a worst case). Ratio is ~0.71, not actually sure if I can set the balance bar accordingly (seems like a lot) but lets say we can. So if I apply 70lbs, I am now seeing 71% of that at front MC and remainder at rear - and the brakes should be at equal pressure front and rear. This means my comfortable 70lb number I pulled out of my ass is really only 50lbs. To get back to that I probably need almost 100lbs of pressure which does start to sound a lot like a workout. And 1100psi is probably not gonna be enough to lock the tires, but then again given the shit rubber I have on those 14"s maybe I am worrying too much. This comes into the second part -

Of course that is all kind of moot because we aren't looking at piston sizes in the calipers - which is key because front vs rear calipers piston size differences will result in different wheel clamping forces/ability to lock the tires, which is what we actually give a shit about. Ideally we should set balance bar based on that. This probably does not tilt it more in our favor though, because smaller rear pistons is going to work out to less actual force applied to the rear caliper, which is why I went with two different sized MCs to begin with (i.e. so balance bar can sit at roughly 50%).

Anyway probably buggered some numbers in that rant, but oh well. I figured for street driving the 0.75 would be fine with the 7:1 ratio, maybe not ideal, but it sounds like I might be changing my mind once I have to drive around for an hour or two and start regretting skipping leg day so often.

[digger]

The fluid ratio of the stock brakes and bigger masters made for a very hard pedal with minimal travel. It probably would be ok for a track car but on the street I was not very comfortable with it especially if I needed to panic stop.

Looks like many the pics are down today, hopefully they were working when you viewed that thread? Photobucket sucks with their bandwidth limitations, I will have to recreate the thread here with re-hosted pics.

i'm confused the stocks MC is 0.875/0.690 so which bigger size ones didnt you like?
what did you settle on?

[JehTehsus]

I ended up picking a 0.75 for the fronts and 0.625 for the rears - they actually just arrived today. I think I probably went to big on the fronts, looking over it again.

Also, quick build update before dinner:

Plan B for fuel pressure regulator will work well I think. Going to cut and fab up a little bracket to mount to that stud on the IM this weekend.





Throttle body modifications are not quite there yet. I am pretty much perfectly happy with how the intake air temp sensor worked out (little copper tube with protective heatshrink boot on the tip). Ended up tapping throttle body for 4-AN and getting a 4-AN smooth hex plug, which I then tapped to 1/16NPT. I know the o-ring is visible in that picture, I am actually relying on red loctite to make the seal. The IAT itself will be sealed into the 1/16 NPT with blue loctite. Came out as well as it could have, not perfectly straight but I don't have a drill press.

The right angle 4-AN to 6-AN fitting is too big by a friggen hair, which figures. Need to find a different 4-AN fitting I suppose, but not the end of the world. That fitting will be providing manifold vacuum/pressure reference to the vacuum station, which will feed the MAP sensor and probably get tied into some turbo goodies later on down the road.



And yes, I know throttle plate screws are missing.



These are the sensors: 2 combination pressure/temperature and the air intake temp/ IAT shown above. The PTS's will be going on oil and coolant respectively, another is already present on the fuel rail.

[whodwho]

i'm confused the stocks MC is 0.875/0.690 so which bigger size ones didnt you like?
what did you settle on?

Sorry that is a bit confusing, I was running behind and a little too quick to reply. 8^(

I meant bigger size in general, without a lot of mechanical advantage the pedal is too hard and no modulation. Even with the max leverage setting on this bracket (7:1) it was still not good for me with the .700 and .625 MCs and the stock calipers. When I went to the M3 brakes the fluid ratio of those MCs and the M3 calipers made it usable again. I ended up using a .750 and .625

[JehTehsus]

Mostly stuck working on the chicken coop this weekend, but I did manage to rough out a fuel pressure regulator mounting bracket and get the coils all mounted. Coil mounting panel still needs a few adjustments (probably going to bolt on a strap to keep it under tension, right now it will likely 'flap' a bit which I obviously don't want. Also need to redo the plate-to-engine bay mounting holes, I need it about an inch further back).

I also almost managed to get to degreeing my cam... feel like every time I get started something comes up. Soon. Catch can also arrived, so I am at the point now where I need to pull the booster, get the Massive pedal kit in, then mount the E85 sensor, fuel filter, catch can (going to try and plumb both coolant overflow and valve cover vent to this), new power steering fluid reservoir, and somewhere to stick some relays. Will also need to get the electric fan mounted and then go through the joys of measuring, cutting and getting connectors on the fuel lines.

Finally, need to figure out a solution for a few last little bits. Primarily running AN-4 for all my vacuum lines (hopefully less of a pain in the ass at 30PSI) and I need to get some BSPP 'G' fitting to AN adapters, as well as a couple of bosch M10x1.5 to AN adapters. Of course I found a company in Australia that has literally everything I need, and at a great price to boot, but they are only shipping stateside at the moment due to the pandemic, so I will likely need to figure out a US-to-Canada mail forwarding setup of some sort. Also need a couple electrical connectors, but digilkey has me covered there.

Fuel pressure reg with a rough bracket I put together (still needs some cleanup and paint). I suck at bending metal, maybe because I just have a bench vise, but overall could have been a lot worse:





I am almost completely happy with how coil packs turned out. Once again, using a vise and angle grinder to cut steel is not a core component of my skillset, but for now it looks okish enough I can live with it:





I came so close to actually degreeing the cam today... friggen chickens. Probably a waste of time at this point, but I figure it is a good exercise to do regardless.

[LowR3V'in]

daym that fpr is cartoony big.

[digger]

is the input fitting to the rail a sharp angle bend like the one coming out to the FPR or a radius one?

I knew the cast log manifold was good for something.....

[JehTehsus]

is the input fitting to the rail a sharp angle bend like the one coming out to the FPR or a radius one?

I knew the cast log manifold was good for something.....

I have another 90 degree swivel fitting I am putting on the feeder end of the fuel rail. It is going to point towards where the brake booster currently is. The plan is to mount the flex fuel sensor below the brake master cylinders, of course sensor is not very big so I have a Y splitter that takes the 8-AN fuel lines down to two 6-AN, one of which goes through the flex fuel sensor and the other as a bypass. Then another Y fitting, and 8-AN hose to the fuel rail right angle fitting. All of this is fed by the fuel filter, which is just a bit after the hardline adapters. Return line is going to be running directly from the bottom of that FPR back to the hardlines.

*edit: Wanted to note, if you are thinking fuel pressure drop due to the 90 degree bends is a major concern, I think because of the size of the 8-AN fittings I am seeing very minimal loss... I was just using an online calculator to check though (https://www.gates.com/us/en/knowledg...alculator.html) but it makes sense with my understanding, where smaller lines are much more sensitive to bends than larger lines. That said, I understand the fuel has momentum and it does not want to change direction, which certainly makes mounting my FPR directly after a 90 less than ideal, but at this point I am somewhat boned on where to put it. As LowR3vin noted, it is a bit of a piglet.

I could mount it on the other end of the rail (*maybe, there is not much more room there), but I would have to flip the feeder end around. That said I don't expect I will see issues; if I do I can certainly move it at that point and cut a couple new hoses.

[digger]

Sorry that is a bit confusing, I was running behind and a little too quick to reply. 8^(

I meant bigger size in general, without a lot of mechanical advantage the pedal is too hard and no modulation. Even with the max leverage setting on this bracket (7:1) it was still not good for me with the .700 and .625 MCs and the stock calipers. When I went to the M3 brakes the fluid ratio of those MCs and the M3 calipers made it usable again. I ended up using a .750 and .625

thanks for the clarification, so here's a dumb question is changing the effective pedal ratio equivalent to changing the bore size (assuming the % change was equal) or does one avenue provide more force advantage with less additional travel in the real world? my concern over the 5/8 was the pedal travel and it was suggested that 3/4" with 7:1 would be a decent baseline if the pressure limit valve was deleted.

Do you know what size pistons are stock FR and RR stock and the M3 FR you have? numbers i found are 48.0 mm & 33.0 mm for stock but not sure.

based on my calcs the stock pedal box ratio is ~4:1 and the Lee's linkage is 1.7:1 and 1.5:1 which gives the 6:1 and 7:1 settings. Sound about right? i figure maybe i should do some actual calculations before installing

[mikey.antonakakis]

FWIW, my Nuke cam gear is pretty much dead on to the cam specs (Enem Z45 turbo) when the "zero" marks are lined up.