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Tofuball's '94 XFi; It's all about city MPG
Topic Started: Mar 12 2011, 08:59 AM (39,433 Views)
t3ragtop
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Turbo3 and Twincam Tweaker

i'd advise you to take some time with the megasquirt on the bench to get everything set up. use a megastim or jimstim to simulate inputs and use tunerstudio software on your computer to dial in your base tune.

start from scratch using the bench set to enter your injector data, displacement data, timing data, sensor curve data, coolant data, etc. then use the megastim to simulate different points from idle and up. if you pay the license fee for tunerstudio it will allow you to use the autotune feature. then you can use your laptop to log data and play it back to autotune which will then tweak up your mapping.

all that will help you get your base tune close before you ever try to start the engine. be sure that you save the msq file as that will become your base tune.

once you have the wiring completed, pull the ignition and injection fuses and roll the starter while using the trigger wheel signal logger. that will let you tweak in the vr signal using the 2 vr potentiometers on the megasquirt board. that diagnostic feature is very much like using an o'scope to view the vr signal and it allows you to peak the timing signal.

run all the preset tools to dial in the tps signal alignment, set the dwell, etc. i also checked the o2 signal in free air to dial in that alignment. i just selected my target afr, rpm range, and used very small steps so that it wouldn't work against tuning progress.

start the engine and watch the temperatures come up while idling. if your idle is acceptable, you can start the tuning procedure using autotune while you drive. keep your throttle angles light and low while the application learns and adjusts the mapping for you.

always remember to name and save each file as you go through the tuning process. once you get used to the filing system and refine the tuning it's pretty easy to call up and load files to the megasquirt. you have the option of loading a file for economy or another for performance from the supervisory computer.

i make very small adjustments and make notations on what i do every time. if something goes awry, you can drop back to the previous file. also, tunerstudio lets you compare 2 files side by side for diagnosis.

got any pics of your hardware?
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Tofuball
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Strange Mechanic

All the other cars I did I just guesstimated and did some calcs, then drove around and modified things from datalogs.

Though, I still haven't had a chance to even try to install the thing. Been so busy with other stuff. Welding for hours and hours and hours.

So I found out I had a bad ball joint - finally got some free time today and pulled the whole assembly. I think I'll pop in new shocks, tie rods, and endlinks too while I'm in there. Still rust free on the frame, but the paint is coming off so I'll clean it up while I'm in there.
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Tofuball
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Strange Mechanic

Rock auto had everything but shocks (including pads and rotors) for $161 shipped - for both sides! A-arms with ball joint were $33 ea + S&H.

I'm also going to sand down and repaint the frame horns. Using what I have available - etching primer, paint, undercoat.

The lack of a separate forward attachment point is really crazy to me. Maybe I'll fab up some kind of bar that slips under that front bolt and braces somewhere to the frame.
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Tofuball
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Strange Mechanic

The passenger side frame horn is flawless so I'm going to leave it alone.

I used a self-etching primer on the drivers side and then coated it with some bright red paint I had - once that cures I'm going to use the undercoating. If any undercoat flakes off, it'll be really easy to see the bright red peaking through!

Got the new tie-rods and endlinks installed - got the springs apart, just have to wait for the new A-arms to arrive to finish this up . . .
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t3ragtop
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Turbo3 and Twincam Tweaker

tofu, the most shocking thing about the frame horns is that they were fabricated and spot welded leaving the seams wide open and unsealed. they actually rust from the inside out so covering the outside with undercoating doesn't do spit to slow the rot.

i sprayed mine on the inside with a zinc phosphate/ phenolic coating from eastwood company. you don't even need to drill an access hole, just use the holes in the front that take the pins to hold the plastic splash guards on. the spray bomb has a plastic tube with a brass nozzle on the end that gives it a hemispherical spray pattern. shove the tube in the hole and guide the tube up or down in the frame horn, push the trigger, and pull the hose out. you can also get the tube to run forward into the frame rails to shoot the rustproofing in there, too. you can easily access the rocker cavities through the push pin holes for the plastic scuff plate at the bottom of the door frame.

you'll see what i mean about the open seams when they start to get the phenolic paint dripping out everywhere. ^o)

when the chassis is exposed to the temperature swings that take it through the vapor pressure point (dew point) the insides of the frame horns, frame rails, rocker cavities, etc. "sweat" like a cold beer can on a hot day. that actually puts that condensation directly on uncoated steel and the rust commences. anything that you do on the outside doesn't really take care of coating the inside so the internal frame coating does a real good job of protecting the back side of things.
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Tofuball
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That is one school of thought, and it'll probably be ten years before you even have to look at the thing again . . .

I did have surface rust due to leaking brake fluid. I already sealed the whole thing except the hole on the top, then I was planning on spraying a corrosion inhibitor in there yearly, but after looking up the coating you mentioned I think I'm going to use that (at least first).

Thanks for the recommendation.

----

Work done last night:

Finished coating the frame horn with undercoat.

I cut the front springs 3/4 a turn, cleaned and re-greased everything and got the shock units back together. got the new rotors on ($5 a rotor? awesome!) and re-greased all those bearings too. I'll be able to button this up when the A-arms finally arrive (should be today).

In the rear I plan to weld a plate on the bars (name escapes me right now) to square it and make it stronger, cut the rear springs 3/4 or 1 turn, and install the rear swaybar.


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Woodie
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My experience is that you want to cut less in the rear than in the front. When I cut one coil all the way around, the back squatted down too much.
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Tofuball
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Strange Mechanic

Thanks for the warning, guess I'll try 1/2 a turn to start!
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Coche Blanco
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Troll Certified

You'll like 1/2 a turn.
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Tofuball
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So, since the last time I drove the car, I've replaced both A-arms, tie-rods, end-links, rotors, pads, and transmission output shaft seals. I cut the front springs 3/4 a turn and the rears 1/2 a turn. The rear seems a knuckle higher then the front, but we'll see if that is still the case after I replace the giant battery with a small one. Any recommendations?
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Tofuball
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Alignment done.

Code:
 
FrL: Now : Befo : AcTolerance + FrR: Now : Befo : AcTolerance
CAM: 0.4 : 0.50 : -1.0 to 1.0 + CAM: 0.3 :-0.70 : -1.0 to 1.0
CAS: 3.3 : 3.20 : 02.0 to 4.0 + CAS: 2.9 : 2.80 : 02.0 to 4.0
TOE: 0.05:-1.05*: -.08 to .08 + TOE: 0.03:-1.07*: -.08 to .08
SAI: 13.6: 13.6 : NONE SPECIF + SAI: 12.8: 12.5 : NONE SPECIF
InA: 14.1: 14.1 : NONE SPECIF + InA: 13.1: 11.9 : NONE SPECIF

ReL: Now : Befo : AcTolerance + ReR: Now : Befo : AcTolerance
CAM: 0.5 : 0.50 : -1.0 to 1.0 + CAM:-0.6 :-0.60 : -1.0 to 1.0
TOE: .07 :-0.01*: 0.00 to .16 + TOE: .15 : 0.09 : 0.00 to .16

TOTALS FRONT
Cross CAM: N 0.20 : B 1.10*: T-1.0 to 1.0
Cross CAS: N 0.40 : B 0.40 : T-1.0 to 1.0
Cross SAI: N 0.90 : B 1.00 : T-NONE SPECI
Total TOE: N 0.08 : B-2.12 : T-.16 to .16

TOTALS REAR
Cross CAM: N 1.20: B 1.10 : T NONE SPECIFI
Total TOE: N 0.22: B 0.08 : T 0.00 to 0.31
ThrustAng: N-0.04: B-0.05 : T-0.15 to 0.15

* MARKS OUTSIDE SPECIFICATION
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Tofuball
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Strange Mechanic

So, what is stopping us from just using some $20 a pop RBC2 (UPS) batteries?
Or two in parallel? Still $40, and very light compared to a stock battery.

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DevLocus
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[ *  * ]
I would worry about cranking amps and the charging circuit.
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Tofuball
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DevLocus
Aug 18 2011, 06:10 AM
I would worry about cranking amps and the charging circuit.
Hey Dan, been a while :)

What kind of things would you recommend I look for? The RBC2 takes the same charging range as a regular "wet" lead-acid battery. The question is, how many of them would I need? They don't have a cold cranking amp rating.
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Tofuball
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These batteries _seem_ to have about 90 cold cranking amps and 7.2ah. Two should be just fine, I'd think.

Made a separate thread: http://geometroforum.com/topic/4469914/1/
Edited by Tofuball, Aug 18 2011, 03:39 PM.
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