87 Fastback L47 Chump Car/ Lemons Project.

Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.

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FieroWanaBe1
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87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

And so the story goes:
A group of collective gear heads were interested in building a competitive chump car. Half the team has been and is previously racing in a prepped e30. The car isn't terrible, but its been unreliable, doesnt make the expected power and the owner just doesn't have all his priorities right as far as addressing the issues that are affecting the teams performance. So our plan was to build a car that would be completely different and use economical parts, that are cheap and easy to obtain on short notice, unlike a BMW. Our car needed more power, and more brakes, and to be able to at least turn safely/predictably.
Our initial plan:
We decided we wanted a 3800 for reliability, after scouring Craigslist and classifieds for running cars, all we could find for sub 400$ prices was a 95 Olds Aurora, not the motor we were looking for, but would provide a cheap yet powerful powerplant.
We were given a MK2 GTI shell, we had the engine and subframe from the aurora and we would devise a way to mate the two in a mid-rear layout.
The shell was clean, but barren. After deliberation, we decided, the work to accomplish this would be too much for our first totally custom crap can racer. Plus the owner of the GTI was upset we didn't have a VR6 to use :cry: . :-o
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So the team decided against my advice to use a rust parts car fiero. The suspension isn't going to make it competitive against the e30's that dominate, especially the e36's. But, we will be able to over come most of the obstacles, without having to devote all our time to R&D and fabrication, and we will still have a light, powerful, and different car combination.

So the plan for the car is:
87 GT Frame, stripped, seam welded, rust repaired/reinforced.
-We have completely stripped the car, and are starting the lightening and seam welding, and are reinforcing and replacing the rusty and weak areas of the frame. I have some different ideas we will try to implement on the car to increase rigidity and strength of the main frame rails (which is pretty poor).
Image
The motor will be a 1995 aurora l47 running a '7730 ECM tuned using Ryan Hess' .bin file
-I already have the Moate's APu1, we are working on acquiring a wideband 02, and have arranged for some dyno-dynamics dyno time through a friend.
I have questions on this, and I will post later about what to do about the 95 issues with Ryan's .bin
Image
The suspension will be:
-GM U body minivan rear knuckles/hubs/brakes on the rear with either cut minivan, Aurora or Fiero springs (whatever our testing and evaluation indicates is better suited). bushed with Solid cradle and Poly suspension bushings (included on car as purchsed) a small rear bar off a ford zx2 may be added (probably not). Rcc Bump steer kit (included again) may or may not be used.
-The front will be all Fiero with Lebaron rotors and s10 calipers with hand cut brackets per internet drawings. All the bushings again are poly up front. Spring will be severely cut, and lowering ball joints. Stock sway bar.

The cage will be an eight point with several tie ins to the key structural areas of the Fiero frame.

The body will be based on the 87 GT with lots and lots of mods to "replicate" and F40LM, our car has been dubbed the Ferrario F4.0. (large radiator extractor, rear hatch, big wing (hand made), etc.)

Image

Before anyone starts spraying negatives, please understand this is a long term build, all the team members have lots of the necessary experience, and all in different areas. We have, combined, several MIGs, TIGs, a CNC bender, lathe, mill, press brake, bead roller, plasma, access to CNC lasers, lathes and mills. I am a Mechanical Engineer working in the railway MOW industry, one team member owns service shop (Rawsomotion), another runs his own Fab business (Arc Asylum), another worked and works for multiple circle track specialty shops. And our final member is a computer science geek who like cars almost as much as Macs, we have the brains and muscle to pull this off.
The rules have been studied well, and are all adhered too. our current estimated final value is between $500 to $650. More updates and inqiuries soon...

Ill be posting my issues with the engine portion shortly..
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FieroWanaBe1
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

Image
here is a good shot of the rust I'm dealing with.

Image
The plan is to get some 1/8x6x2 Rectangular tubing. and rework them to replace the lower frame rails. We have begun the removal of the large amounts of seam sealer (the plasma cutter doesn't like to cut through it either) and removing the trunk last night.

The Transmission, which i forgot to mention
this part is a little unorthodox, I have two m17 boxes, so the plan it to get it to mate up to the l47. Which means the slave and shifter assembly will need major fabrication and rework, but nothing is impossible.

A bit more on the motor,

it has 205,000 miles, 5% leak down on all the cylinders except #8 it was 11%, at 100psi.
The oil and coolant were empty when it was brought to the shop, after a fill with water and oil it started up and ran fine. with some black smoke and bad smelling exhaust fumes, (the gas in the tank was very varnished, and the pump could barely turn.) The lifters show almost no wear, and the cams have small wear only on the center of the lobe.

As far as assembling a tune for it, my thoughts are this:
since the l47 has the same size injectors as a standard northstar, I was hoping I could try and acquire a base tune for a VIN 9 swapped car, and adjust the BPC to accommodate the smaller bore and totally play with the PE table, or if I am lucky enough to find a VIN Y at the Pick-n-Pull, swap the intake cams, (are springs needed?) and just change the BPC, and see how far the tune is off at that point.

I know Ryan's BIN is setup for 96-99 VIN Y motors. The IAC is different for 93-95 motors, does the one just change to a 96 throttle body? or whole intake? can the 95 IAC be wired into the 7730 the same way?

Maybe Ill get lucky on my trip to the pick-n-pull and stumble on a 96-99 Vin Y with the recall fuel rail, and grab the cams, intake and throttle body.
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The Dark Side of Will
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by The Dark Side of Will »

Yes, you can swap on the '96-'99 throttle...
Wild project. You're going to end up with a very expensive $500 car... but that's the idea, right?
FieroWanaBe1
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

No matter how much we spend, a FIero to the rest of the automotive world is only ever worth $500.
Costs, so far, aren't outrageously more that one would spend preparing any other car, the labor is the high part here. Were replacing the things anyone should when a car is over 25 years old, It's just a lot of them are from another car.
The motor made us money since the car it came out of weighed 3000 lb with out a motor trans or suspension. The aluminum rear suspension, hood and transmission case and wheels gave us even more money back.
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by Shaun41178(2) »

I for one am looking fwd to seeing updates on this project
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by The Dark Side of Will »

FieroWanaBe1 wrote:the labor is the high part here.
That's what I meant... You're going to put a whole lot of effort into it, and in the end you'll have a ghetto racecar... But that's what LeMons is all about! :-D

I'll be interested to hear how the brakes work. The U-body brakes are 11" in diameter, but over an inch thick (I think). The LeBaron rotors are similar diameter but thinner and lighter. You may have differential fade which will leave you with a lot more rear brake than front brake once you heat the brakes up... recipe for a bad day.
FieroWanaBe1
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

From my previous experiences, the front brakes fade much sooner than rears, The e30 got 2 race weekends on the rear pads, and only one on the fronts.
But its a valid point directly comparing specs:
Image
the minivan rotors are much heavier, and will fade much later, but we are really hoping to tune a lot of that with pad compound, since the GM metrics have a lot of choices in pad material and the minivans not so much.

Also, this may be a useless observation, but I think it may have some validity, many street cars are setup with so much front bias on brakes, that the rears gain much less heat that the fronts.
For example:
Image
This TT has enough heat to bring the steel to a red glow in the fronts, but the rears have yet to enter the visible heat range, and steel glows at about 600C, where the rears aren't visible, so they may be as low as 400-500, Perhaps front fade will be an issue, but I don't think it will make it disastrous or unpredictable. Just easier on the needed replacement brake parts.

EDIT:
I wonder how much weight can be cut in the rears from slotting and drilling, Personally I think Drilling is stupid, and just create stress risers, fatigueing the rotors sooner, And I have yet to see any real testing convincing me of any advantage to slotted rotors, but as a weight saving advantage in the rear Id consider it, as well as helping to reduce the pad contact area.
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FieroWanaBe1
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

The whole reason for choosing the minivan brakes, was because of their much larger Hub cartridges. Does any one know how the HD A-body hubs compare to the dinky fiero hubs? I had a Buick Century in college, it had vented rotors, but on a 5x100 pattern, and the hubs looked about the same as the Fieros.

The previous rotor was for a 94 3.1 Lumina APV and a 91 V6 Lebaron

The 91 Trans Port Brake rotor is such:
Image
much better suited, and the same as the A-body with HD brakes. And what I had made my initial assumption on. Now I am doubting if the even larger U-body upright is a direct replacement anyways, and I think we will try to use the pre 91 spec rotor/hubs anyways

I will need to bring my caliper and tape measure to the yard this weekend and make some educated assumption when picking parts.
FieroWanaBe1
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

Ok, for the hub pieces:
Image
top is the 92-99 Minivan hubs
Middle is the A-body HD hubs, and 90-91 U body hubs
and bottom is the Fiero.

They are all bigger that the Fiero's, but the later models have a 33 spline hub earlier have 27, I will have to have the parts store order these to compare...
more on this this weekend.
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by The Dark Side of Will »

I have the A-body knuckles and hubs in the rear of my Northstar car. They are much larger than the Fiero hubs.
FieroWanaBe1
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

The Dark Side of Will wrote:I have the A-body knuckles and hubs in the rear of my Northstar car. They are much larger than the Fiero hubs.
I assume this requires the use of the same outer CV cups?
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by The Dark Side of Will »

Yes, you'll need the outer CV's that match the hub. The A-body outer CV's are a direct swap on Fiero manual transmission axles.
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

is that including the rollers and spider, or just the cup?
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by The Dark Side of Will »

I meant the entire outer CV. Any 440 series CV joint will install directly onto the Fiero manual transmission axle shaft.
AkursedX
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by AkursedX »

FieroWanaBe1 wrote: EDIT:
I wonder how much weight can be cut in the rears from slotting and drilling, Personally I think Drilling is stupid, and just create stress risers, fatigueing the rotors sooner, And I have yet to see any real testing convincing me of any advantage to slotted rotors, but as a weight saving advantage in the rear Id consider it, as well as helping to reduce the pad contact area.
For my RX8, there are slotted rotors out there that are completely cut through the rotor. I imagine they save a bit of weight. I don't know what type of machining you have available, but scalloping the rotors would save a ton of weight.
'88 Fiero GT- 3800 Turbo Best E.T. 11.36 Best MPH 121.50 (Sold and gone)
2021 Hyundai Veloster-N (SCCA Solo D-Street)
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FieroWanaBe1
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

Im sure the jjudges would raise an eybrow to scalloped rotors.

I think the path to go here is the A-body/Early U-body knuckle assembly, less leg work, and I still will gain benifit.

Another change to the plan is we are ditching the 1227730 ecu. It would be great if this car was a daily driver, but the high rpm fueling is crude, and we need all the mileage we can get above peak VE. I am going to attempt to use the 1227165 on this engine, with OSE $12P. It looks increadibly versatile, and can control timing and fueling up to 9600rpm using a single speed density table, not that this motor will ever see that much revolution, but 7000rpm may be there coming out of some sections on the track. I guy at my work has several third gen ECU's including both 7730s and 7165s he has offered to help out. Since I have the stock fiero wiring still, we can use the 7165 ecu and the OSE12P bin loaded and easily integrate it to the car. It looks like there have been succesful uses with DIS on 6cyl cars, I'll see how well it can be used on the 8 cylinder mode. Tuning should be easier too. I just have to find a way to get it close at first. From my ignorance so far, It sounds like the NVSRAM kit form Moates can be installed into the 1227165, and using the Auto-Tune function it should help with getting the engine close. But Im still not sure on how the fuelling strategy works on this definition, and how it works for part throttle vs full throttle, especially compared to the '7730, wich is tailored for light throttle cruising situations, and merely gets close enough for power enrichment and high RPM control. Exact opposite of this car's environment.
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by The Dark Side of Will »

I'm forgetting the OBDI numbers... Is that a Quad 4 computer? The Quad 4 .bin's go to high RPM, but use a split VE table with some weirdness to stitch the two together.
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

It is the ECU used in MAF 86-89 F-bodies, and Corvettes, and in TBI 4 cylinder cars.
This .bin is heavily modified, and based off an australian application. From what I have seen it looks like a very cheap version of running a haltech or similar speed density ECU.
http://www.delcohacking.net/forums/view ... f=27&t=356
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by The Dark Side of Will »

Hmm... Nobody in the F-body community likes that ECM running the MAF .bin, at least not compared to $8D in the 7730. Also, it's not 8192 baud on the com port, is it (I forget what the slower standard is...)
FieroWanaBe1
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Re: 87 Fastback L47 Chump Car/ Lemons Project.

Post by FieroWanaBe1 »

This .bin (OSE $12p) is a map based VE fueling .bin, off of one table. According to:
http://www.fiero.com/forum/Forum2/HTML/119333-2.html#p41
and
http://www.thirdgen.org/techboard/posts ... post2.html
the ecu can communicate at 8192 baud, I'm not very familiar with it, or the aldl communication protocol.
Im convinced to try it with this .bin, if it doesn't work, the '7730 is still an option.

as a side:
My friend has an 88 IROC, 388 ci, AFR 195 heads, Stealth Ram, reprogrammable MAF (which we didn't touch yet, it looks restrictive since its the factory body), and some terrible holly shorty headers, and the terrible Big Mutha Thumpa cam (I really tried to get him to not use it). It has the stock '7165 ECU.
Ryan Gick did a mail order chip for it, it ran great, maybe on the rich side (winch is safe for Ryan's sake and the car) I think the ECU did its job, his transmission builder however missed the mark and it short shifts at 5000 rpm.
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