High Altitude Supercharging

[ThaDoubleJ]

Now that my Wavetrac LSD and Unicorn/Sachs clutch are in, I have this VF supercharger sitting in my dining room that needs to go in next, so I'm starting this new thread about it.

Unlike turbos which just make up for altitude by spinning faster and engaging the wastegate later, superchargers need air to make boost as their RPM is fixed to the engine's RPM, and there's no air where I live.

According to some math provided by Jim, who's at a similar altitude as I am, the 6lbs that the kit should make at sea level will become 2.5lbs up here near Denver. Imagine the zero boost I'll be making when I go into the mountains for the curvy roads....

I can put a smaller pulley to get back to 6lbs, but with less air to work with, is the engine working harder to spin the supercharger faster to create that boost? Will it run lean? I doubt it, but I don't know and I aim to find out.

I'm playing one sided phone tag with Frank at TTFS to talk about tuning and about their upgrade kit at the moment.

Along with the SC I'll also be putting a Zion fan and shroud and removing the factory aux fan because it looks stupid. Engine fan goes away also.

I printed all 70 pages or so of instructions and pictures and put them in a binder for bedtime reading. After passing emissions, getting my tags renewed, paying the fines from expired plates (car was on a lift since May) and doing some dyno pulls to get a baseline wheel HP output, I'll be making this a winter project. Oh, and having the AC evacuated, need to find a shop that can do that for me.

One place I got hung up on pretty quickly is that VF recommends replacing the coolant sensor while I'm in there. My research shows that there are at least 2, possibly three of them. One in the lower radiator hose that may or may not just feed the gauge on the cluster, one under the intake manifold and one in the thermostat housing, which may or may not be one and the same as the one under the manifold, if the V8 even has that. Can anyone clarify all that for me?

Second place I got hung up is the injectors, VF basically says to figure it out, and if you can't swap them, the project is over your head. I searched a bit and found not much on replacing them, and that's something I may need to do twice depending on how much power I go for in the end. Is it a nightmare job?

Also planning to figure out an oil catch can somewhere along the way. I know it's got a separator somewhere in there already, but I'd feel better with a catch can as well. According to the government, my feelings are what's most important, so that's what I'm gonna do.

[wagons ho]

All I can say is good luck to you.
Being at sea level, I've always down jetted my old cars when going cross the Rockies. And been amazed how down on power the are. Plus side, not much in detonation problems.
Centrifugal makes most boost at rpm.
Would a twin screw have as much boost problems at 4-5000 feet?

[ThaDoubleJ]

The power loss is surprising, that's for sure. I've run into many people with smoking brakes and sea level plates on the side of the road calling a tow truck because they think their car is broken. Once I explain downshifting and air pressure, they're back on their way. I dyno'd my Ducati 996 once....84 uncorrected wheel horsepower, very humbling. Not sure about twin screw vs centrifugal, but as roots and twin screws actually smash air into the engine vs centrifugal that just flings it against the housing, my guess would be that they'd work better at low RPM, but become even more inefficient at higher revs. That's completely made up though, as I'm just wrapping my mind around supercharging, it's a bit different that my old turbo Subaru.

[KeysCoupe]

I have a twinscrew on my 525, but I'm at sea level. I haven't put many miles on the car since I've had it as I'm storing it in a garage until I finish a new storage location. The package is an ESS TS1, which means there is no intercooler.
I've tried to order the TS2/+ kit, but ESS is out of Laminova cores, though I have the manifold endcaps coming in from Norway next week.
Though a Rootes and a twinscrew look very similar, they are quite different. The Rootes is an air pump, like a centrifugal. It moves air from one side to the other, pushing it into the intake manifold. The higher the rpm, the more the boost. I have an R53 Mini with an upgraded Rootes and is pushes about 14lbs positive near redline.
The twinscrew is a compressor. It compresses the air within the unit and discharges positive pressure in the intake manifold. The beauty is it produces about 90% of its boost at low rpm, usually under 2200 rpm.
I'll come back later with a bit more.
-Donny

[JimLev]

So when you base lined the car at 5K feet what was your RWHP reading?

You have a dual temp sensor in the water pump housing, one part reports to the DME, the other goes to the temp gauge in the cluster.
The one in the lower radiator hose also goes to the DME for controlling the Aux fan, which you should not remove if you ask me. Boosting will add heat to the engine, that fan will be pretty important when you are using AC in the summer and have your foot to the floor.

Nice engine pic Wagons, your engine?

[ThaDoubleJ]

Emissions and tags are Friday, then I can get the dyno pulls scheduled depending on the weather. It's been in the 70s, but hits 20 tonight, so hopefully the snow holds off until I can get this done.

Water pump is driven by a pulley on the front of the engine I'm hoping, maybe the fan is connected to it? If not, then I'll assume it's under the valley pan, inside of my transmission, or possibly in the trunk somewhere based on where I've found other components of the car. Wouldn't put it past BMW to somehow locate the water pump off of the vehicle, they're pretty sneaky with their engineering. Maybe it's actually in another one of my cars, like my 69 Beetle perhaps?

[ThaDoubleJ]

Somehow I passed emissions with all of 20 minutes drive time since the battery was last connected, but I've heard a rumor that this car checks it's emissions systems whether you drive it or not, so maybe that's true. Got hit with a $30 fine for being late on the tags, not terrible. Dyno pulls are scheduled for Monday afternoon, should be in the 60s, dyno guy (same guy who tuned my Subaru previously actually) says his Mustang dyno is going to hurt my feelings. Luckily I don't have any, sold them on ebay a looong time ago.

Put your RWHP guesses below if you want, I say 213.81 uncorrected at 5500 feet.

[JimLev]

I’ll say 230-235 RWHP.

[philly98540]

High altitude is a sad place for power.

[ThaDoubleJ]

And sunshine, you wouldn't believe how much that ball of fire wears on you when you're a mile closer to it. I'd say we have the best roads in exchange, but after my romp through the Appalachians in March, that's up for major debate.

[ThaDoubleJ]

Well, the dyno test went well I suppose. Nothing blew up anyway. Here's my math: Assuming everything is brand new. Engine is rated at 290 HP. Subtract 18% for altitude and you get 237.8 at the crank. According to Motortrend, it's very difficult to calculate drivetrain loss as it's not linear, but a good guess is 17% off the crank. That means I should see 197.4 at the rear wheels, which is pretty discouraging. I do have a Dinan exhaust and intake, plus some sort of manifold. Let's call that 5HP, minus 18% = 4HP - 17% = 3HP at the wheels, so 200.4 anticipated. The Mustang dyno spit out corrected numbers, so let's pretend I live in Ohio. 290 - 17% = 240.7 + 4HP for the exhaust/intake = 244 at the wheel.

Theories: Car is 20 years old, makes less power. Half of my fuel is about 5 months old, makes less power. Engine driven fan, makes less power (removing the fan from my Dakota gave it the ability to do a burnout, so fans do use some power, clutch or no). Computer has only been powered up for a week or so, hasn't done all of it's bee-boo-beeps yet, makes less power. More drivetrain loss than average? Flex disc plus center bearing plus CV joint plus 4 x CV joints in the IRS?

Recap:
Anticipated Sea Level RWHP - 244
Anticipated ~5500 feet RWHP - 200
Actual corrected dyno RWHP - 225


More math: If the 225 is correct, than I've either lost 19 ponies at the crank (I've heard of fans burning 15-20, so maybe?) or the 17% number is for old timey American cars with a single piece driveshaft and solid rear axle. If that's true, we're talking over 60HP chewed up between the flywheel and the lugnuts, that sucks.

One odd thing, the first pull wasn't lean, but it didn't go rich, sat at 14.6 through 2600 RPM and then dropped to around 12 at 4600. The 2nd and 3rd pulls it dropped to 12 as soon as he punched it and stayed 11.9-12.8.

The tuner guy says based on his experience with superchargers up here, he's expecting me to see 4lbs of boost if 6 is the goal. That'd be better news than 2.5, but only one way to find out. Stay tuned.

Also...What's redline? The tach starts getting red about 5700, but I've heard 7K thrown around. I figured 6 would be a good shift point.

[JimLev]

For reference when my stock 540 (282 HP in 2000) was on the rollers at pretty much sea level I laid down 251.2 HP AND 286.6 Torque.

[ThaDoubleJ]

That's pretty much exactly 25/25 above what the Mustang dyno reported, or 33 more if we take the 8HP gain from 2000 to 2003 into effect, or 38 more if I pretend that the Dinan parts actually make more power. I turned out 261 torques.

Do you recall what make of dyno that was?

[JimLev]

I don't remember, that was back in 2005.
The only thing I recall is the roller was filled with water.

[ThaDoubleJ]

Who knows stuff about secondary air injection? This kit has me moving some sort of doodad, the pump I'd guess based on the size of the wires supplied, across the car and into the space behind the bumper.

On my Forester XT, the SAI system was a disaster of broken parts and constant work. Since I NEVER once drove that car on the street and it was a trailer queen show/track car only, I removed and deleted all of the SAI parts, but of course kept them and put them back on when I sold it and un-deleted them.

Do I need this SAI complexity on the 540? Can it be deleted, assuming of course that I'll never drive it on the street. Hell, I'll never even start it again, just to be safe. Hypothetically of course...

[JimLev]

Will you need it to pass CO inspection?
The pump only comes on when the engine is cold and somewhere around 40ºF outside.
The DME turns it on as well as powering that small vacuum solenoid on top of the intake manifold on the pass side.
It will run for 2 min or less and then both items shut off.

[ThaDoubleJ]

Nope, CO checks OBDII for codes, goes on the rollers (or doesn't, it's completely arbitrary) to pass idle/accell/decel and then they send you on your way. No mirrors, no hoods popped, and the car has to be at full operating temp. I've heard it run, sounds like a jet engine.

I'll need someone to tell me what a DME is as well, I've seen that initialism on Philly's big thread 1100 times or so, I'm assuming it's a BMW word for ECU or CPU?

[ThaDoubleJ]

Ok, I finished the Philly megathread. Question 1: Spark plugs aren't talked about too much. I talked to Frank the other day, he suggested I go a temp colder, has anyone done this? Plug recommendations? The kit I bought has some NGKs in it, probably stock.

[JimLev]

Yes the DME (Digital Motor Electronics) is the ECU.
I’m using NGK Iridium plugs one heat range colder than the stock NGK Platinum plugs.

[ThaDoubleJ]

I've got BKR7E-E 4476 V Power NGK-R plugs with the kit. I don't think the 4476 matters, only on the box, not on the plug. Says they are a resistor type plug. FCP and ECS really want me to use the 4 ground strap models from either Bosch or NGK. According to the NGK website, I should be using BKR6E, heat range chart says these are one step cooler, so I'm good to go on plugs. Unless I want the new RUTHENIUM of course, they're even specialer! What do you all think, stick with these regular old plugs or get something super fancy? I'm sure they'll all make fire, just curious if any of them last any longer.

[philly98540]

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I use NGK Iridiums BKR7EIX gapped at 0.026”.

[ThaDoubleJ]

Yeah, looks like these supplied plugs are nickel/copper, so I think I will upgrade them. Are you running the gap .006" closer just to make sure the spark stays hot with the higher effective compression ratio discussed extensively in your megathread?

[philly98540]

Yes.

[ThaDoubleJ]

I might actually spring for these Ruthenium plugs, they have an N/A design and an F/I design, about 90 bones for the set, probably never put enough miles on them to need a replacement.

[ThaDoubleJ]

Ok, just re-searched the megathread for injector information. TTFS kit comes with 8 new injectors (that are red and plastic according to the photo, but the photo also shows a crank pulley, which is incorrect), but according to the megathread, Philly did 450ish RWHP on 30# red Bosch units at 12ish PSI. I have no-name 30#ers with the kit, and if my goal is 8-9ish PSI with a 3.25" pulley, then there's no reason for new injectors, either here or if I decide to move to Tennessee, yes? Someone mentioned that the no-name injectors seem to work fine. Do I stay with them, or try to source the Bosch reds? No-namers have 3 big holes on the firing side, kinda makes me want to go look at my old Subaru injectors and see if they have finer holes. Can anyone confirm number of holes in Bosch Reds? I found Bosch greens, $600 bones probably overkill for my goals. Cannot find Bosch reds with a quick search, just Bosch greys, which I'm assuming are stock.

Phillyplate: I'm a little lost here, there was a 1.0 and a 2.0, were both used on the 2.87 pulley, with the 3.25 pulley being fine with the stock setup, or was the v1.0 with the 3.25 and the v2.0 with the 2.87? I'm guessing there are some additional threads to the megathread that I'm not aware of that address some of this. Looks like Mr. GG was going to post a write up (Edit, May of 2020, found it). Maybe I answered my own question, and belt slippage seems to start right around my target boost levels of 8-9 PSI, that sound about right?

Fuel Pump: Looks like Philly moved up to a 320 (is that LPH?) AEM pump at some point in the past, neither TTFS' kit nor Frank mentioned more fuel pump for the 3.25 setup, so I'm assuming the stock pump is up to the task?

Back to the SAI system, anyone know if I can just 86 it and delete it?

Getting excited to get started, but it's a winter project and winter is making no appearance in Denver. 70 degrees today.