PFF - Pennock's Fiero Forum, PDA Edition

The White Bug (Page 39/46)

pmbrunelle

MAY 08, 07:45 PM

quote

Originally posted by pmbrunelle:
At the higher MAP level allowed by the new clutch, the VR crank sensor analog-to-digital Maxim MAX9924 interface has been malfunctioning and causing the ECU to lose synchronization with the crankshaft.

I did a quick-and-dirty test with a 4-pin HEI module acting as the crank sensor interface; it worked well. Over this winter I'll figure how to install the HEI module cleanly.

Last weekend, I completed a support bracket for the HEI module from a piece of laser-cut metal with welded-on spacers.

Because the HEI module is grounded via its case, I wanted to use a metallic non-corroding material to ensure electrical conductivity to the engine block. I used stainless steel 304.

Here are the new and old solutions side-by-side:

The support bracket screws onto the engine block:

With the knock module installed like before:

I still need to do the wiring to finish this modification.

ericjon262

MAY 09, 08:03 AM

I really like the use of the HEI module, mainly because it's an off the shelf part, that if it fails, is relatively quick and easy to acquire. Nice work.

------------------
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.

82-T/A [At Work]

MAY 09, 09:18 AM

quote

Originally posted by pmbrunelle:

I haven't posted a picture of the car itself in a while, so here we go (three weeks ago when I washed it):

You've done a fantastic job with this car, and I'm very impressed with the work you've done in the engine bay, etc. You've actually "engineered" components yourself, and not just bought stuff off the shelf and slapped things together. You have every right to be very proud of the work you've done.

I don't know if I missed it... but how do you enjoy driving the car? Compared with stock (if it was running well at all originally)?

Did you have any opportunity to drive it as a 3.1 without the turbo? I'd converted mine to a 3.1 (ended up being 3.2L with the larger pistons), and I didn't notice a difference at all, but my car had many other issues at the time. I still plan to go through it all, but in a storage unit it sits! Haha...

pmbrunelle

MAY 09, 07:41 PM

Since I am the mechanic for this project, and I don't hate myself, maintainability is a consideration!

********************************************************************************

From 2008 to 2016 I drove my first Fiero with a near-stock 2.8 L V6 (and 5-speed Isuzu), so I have that as a point of reference.

I never drove this 3.2 L car without the turbo. That said, the turbo sizing is not like that of a typical modern 4-cylinder turbo car; the turbo only really wakes up and boosts the midrange and top end. Below around 3000 RPM in calm driving, the turbo isn't being spooled much, so the car works like it has a naturally aspirated 3.2 L V6.

Going from 2837 cc to 3192 cc is a 13% increase. My car has 7.4 compression compared to a stock Fiero's 8.9, so I think the reduction in compression results in a 5% torque reduction. Therefore, I think that my engine makes about 8% more (naturally aspirated) torque than a stock Fiero engine produces.

From experimenting with different boost pressures, I think a 20% torque change is needed to result in a "nice" noticeable improvement on the butt dyno. Others may have more sensitive butt dynos than I do.

In terms of daily driveability/friendliness, the best mod I think I did was to run the M19 Muncie Performance transmission gearing available in the 1984 4-cylinder Fiero.

Overall 1st gear reduction (M19 Muncie Performance): 14.47
Overall 1st gear reduction (MG2 Getrag): 12.64

That results in a 14% torque increase.
Additionally, when taking off from a stop, clutch engagement occurs at a 14% lower road speed than with a stock Fiero.

So, in terms of the amount of clutch slippage needed to get moving from a stop, I count the ratio effect twice (squaring it), and so I consider clutch slippage on takeoff to be improved by 30%.

When I drive my car in town, I don't have to slip the clutch much to get going. It's really quite pleasant in the city (from memory, better than stock Fiero). You don't have to rev the engine much, and it's quite hard to stall on takeoff. Even uphill starts are easy to do.

Displacement helps, but I think the gearing was key in making my car drive nicely in town. The turbo of course makes the engine pull harder when you open up the throttle, and that is satisfying in a different way.

There is some room for improvement in the powertrain, but right now I find the stock 84-87 Fiero brakes/suspension to be the weakest area of my Fiero's driving experience. The car handles like a marshmallow! I think I will like the handling better with the wheel/tire/brake/suspension mods I'm working on.

[This message has been edited by pmbrunelle (edited 05-09-2023).]

82-T/A [At Work]

MAY 10, 08:30 AM

quote

Originally posted by pmbrunelle:

In terms of daily driveability/friendliness, the best mod I think I did was to run the M19 Muncie Performance transmission gearing available in the 1984 4-cylinder Fiero.

Overall 1st gear reduction (M19 Muncie Performance): 14.47
Overall 1st gear reduction (MG2 Getrag): 12.64

I wanted to respond to this separately, because I totally agree. I had a 1985 Fiero GT 4-Speed many years ago. I bought it used, and sold it two years later. But I drove it around a lot, did a few things to it, but really what was unique about it is that the heads had been decked. It was done before I got it, but the heads had been decked to get rid of a cyl head warp, and it bumped the compression up a fair amount to something like 9.1 or 9.2 (I can't really remember). The intake had been milled to match the cyl heads too, so when I tried to put another intake on (after I'd port-matched a spare), it wouldn't fit exactly as it should. But in addition to the compression, it also had the 4.10:1 4-Speed performance transmission from a 1984 Fiero dropped into it as well. The acceleration was really significant. It was way quicker off the line than my 1987 Fiero SE / V6 that (at the time) had a 3.33:1 GX3 automatic. It would pull away hard, but then around 65-70 the automatic Fiero would begin pulling on it (which didn't make much sense to me, but never the less). But yes, I can only imagine how much fun that little car is (with your modifications) and that 4.10:1 4-Speed in there!

quote

Originally posted by pmbrunelle:
There is some room for improvement in the powertrain, but right now I find the stock 84-87 Fiero brakes/suspension to be the weakest area of my Fiero's driving experience. The car handles like a marshmallow! I think I will like the handling better with the wheel/tire/brake/suspension mods I'm working on.

Like ~15-20 years ago... I was blowing all my paychecks on Fieros, and I had like 5 of them at the same time at one point. Depending on what you're looking for, what I found worked best was to get the WS6 springs, and mild-shocks, either Y99-rate shocks, or even if you want a bit more aggressive... the KYB Gas-Adjust shocks. I then also went with poly bushings on the front sway bar. That's with all the stock geometry of course, but that seemed to be the best of both worlds for me. The stiffer springs really reduced any roll I was getting during cornering, and the mild shocks worked well to prevent any significant road vibration. I added a rear sway bar as well, but that added some unpredictable oversteer in situations that I wasn't comfortable with.

I had a few other combinations that sucked. I went with all poly and KYBs (and normal Y99 springs that were original), and that felt like **** . Every pothole or dip felt like a jackhammer. The springs were doing nothing.

At one point I also had the WS6 rated springs (which I got new from NAPA), and KONIs... and that was too rigid, but it was better than the previous, which had the soft springs.

I mean, I'm old now... mid 40s. So what I would be looking for is different than you of course, but for me... I like sort of the "German" handling, which is stiff springs, and softer shocks. That gives more of the feeling that you might get from a Golf GTI or a Jetta, or even a Porsche 944 for example.

For brakes, you'll probably make all your own stuff, but I was having a LOT of issues with brake fade. I mean... I was in my early 20s, and I was basically flooring it at every light, and getting stopped at every light. My front rotors at the end of the day would be glowing red. The fade was horrible to the point that my braking ability almost halved when they were really, really hot. Anyone who says the stock Fiero brakes are sufficient for the stock V6 is probably not driving it spiritedly. If someone was going to actually use the Fiero for an SCCA Solo-1/2 event... the Fiero would fail hard.

I noticed the most significant improvement I could find, across the board, was replacing the stock front rotors with cross-drilled rotors from the Fiero Store. I never had a single problem after that. And to be clear, I'd replaced the front rotors a couple of times because they'd warped due to my very aggressive style of driving down here in Miami.

This is what I ended up doing before I put my car into storage:

This was literally weeks before I put it into storage (where it sits currently)... it was like 13 years ago... which sadly is how long it's been in storage. Everything here is mostly stock. I've gone with poly bushings (but I may replace the lowers with rubber bushings when I get it out), and these are WS6 springs, and KYB shocks. The brakes are from the "Grand Am" brake upgrade. Not sure if you can still buy that anymore, but I got it from the Fiero Store I think... years ago. Probably better options now...

EDIT: I wanted to say, I really like the fact that you're keeping the car aesthetically looking stock. It looks so sharp the way you've done it. You see some "modified" and custom Fieros on eBay that people have gone through, and it really makes me sad. You've done such a good job improving the car, while not making it look stupid!

[This message has been edited by 82-T/A [At Work] (edited 05-10-2023).]

zkhennings

MAY 10, 02:57 PM

Looking good and looking forward to seeing your suspension mods!

pmbrunelle

JUN 05, 07:42 PM

The new struts and rear LeBaron brakes are now installed.

These struts will give room for the 17x9 ET+40 wheels and 255/40R17 tires that will be going on the rear of the car. I'm using a custom aluminium spring perch sitting on top of the KYB strut's weld bead.

Besides polyurethane bushings in the rear control arms, the rear suspension is otherwise stock in this incarnation of the White Bug.

*****Rear Brakes*****
-LeBaron rotor: Raybestos 7993R, slotted and balanced by myself.
-Caliper bracket: 3/8" steel, yellow zinc plated, cut by sendcutsend.
-Caliper: 1985 Cadillac Seville, modified for use with banjo bolt bleeders: https://www.fiero.nl/forum/Forum2/HTML/144809.html
-Banjo bolt bleeder: Goodridge 992-31BNC
-Hub: stock Fiero hub, pilot diameter turned down to fit LeBaron centrebore.
-Pads: Powerstop Z26, GG friction rating.

Perhaps at some later time I'll try to make a drum-in-hat parking brake work, but for now, I'll be rolling with the upside-down Cadillac calipers and banjo bolt bleeders.

ericjon262

JUN 07, 01:05 AM

if you still have the original bleeders installed as well, one of these reverse style bleeders may help expel air from the caliper slightly better by pumping in through the bottom and out through the banjo bolt, then use the banjo bleeder to get the air from the lines.
https://www.amazon.com/Phoe...s%2Caps%2C288&sr=8-2

or maybe it works well enough standalone.

pmbrunelle

JUN 07, 07:22 PM

The calipers still have their original bleeders.

I'm guessing that the banjo bleeder will be sufficient to fill the system from dry (to be seen).

However, for future maintenance brake fluid flushes, I'll definitely have use the original bleeders in some way, because sucking fluid from the banjo bleeder won't replace the brake fluid that's inside the caliper.

I've never tried reverse pressure bleeding. Does brake fluid ooze out of the bleeder threads when you do this? I don't like the mess that brake fluid makes (bad for paint), but I can always rinse a mess with a garden hose.

ericjon262

JUN 07, 09:40 PM

quote

Originally posted by pmbrunelle:

The calipers still have their original bleeders.

I'm guessing that the banjo bleeder will be sufficient to fill the system from dry (to be seen).

However, for future maintenance brake fluid flushes, I'll definitely have use the original bleeders in some way, because sucking fluid from the banjo bleeder won't replace the brake fluid that's inside the caliper.

I've never tried reverse pressure bleeding. Does brake fluid ooze out of the bleeder threads when you do this? I don't like the mess that brake fluid makes (bad for paint), but I can always rinse a mess with a garden hose.

I have always put teflon on the the threads of the bleeder either way. typically, if you open the bleeder enough, it doesn't make much of a mess. I actually prefer the reverse bleeder to any other bleeding method I have tried.