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Anyone know this car.


padgett

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Clearly, they were unable to overcome the instrumentation incompatibility  between the CRT system and the Cadillac PCM. With enough tweaking this should be doable, but is difficult enough that they chose not to deal with it. That's why the fuel economy reading is wrong. I wonder if the tach and other gage readouts are also nonfunctional. If so, I personally  would be a bit disappointed in the mod. Physcially, the complete Caddy powertrain would fit the Reatta as the Ksp (Deville/Eldorado) had essentially the same cradle and engine bay as the E (Reatta) platform, just with a different engine and transmission installed.

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10 hours ago, KDirk said:

That's why the fuel economy reading is wrong. I wonder if the tach and other gage readouts are also nonfunctional.

 

I think there may be several electrical gremlins that haven't been worked out. The CRT displays MAX HEAT on the screen. I see no reason the heat would be maxed out on a nice summer day as depicted in the photos.  It seems to me like getting the tach to read correctly would be hard to do. If the 3800 oil pressure and coolant temp. sensors were used those gauges should still work correctly.

 

Overall I'm impressed with how the Northstar engine swap project turned out. I like the design of the body work and the color scheme. I don't mean to nitpick it too much but... although I like the chrome exhaust tips, I would have painted the exhaust pipes and muffler flat black to hide them instead of making them stand out when looking at the car from the rear. There are a few other little items like that but I think the car looks great and it sounds good too. It doesn't seem to have the get-up-and-go in the video that I expected but he may not be putting his foot in it.

 

 

 

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The big problem starts with having to use a different PCM. The stock Reatta PCM is for a 6 cylinder engine, and of course the Northstar is a V-8. Since the PCM controls the fuel injection, it has to have the correct number of outputs for the number of injectors used and the 3800 PCM is two short. An OBD1 Northstar could otherwise be controlled  (in theory) by a 3800 PCM with the proper tweaks made in the code. The tach shouldn't be to hard to get working as the signal output from the ignition can be picked off amd formatted into the datastream, but that requires  knowing how to do bit level ECU programming.  

 

The bigger issue is the BCM and the fact that in the Reatta it controls everything. Being the "bus master" over all the other modules. all other modules have to transmit and receive a datasteam that is recognized by the BCM for things to work correctly, especially the instrumentation as the BCM feeds all the data for the cluster and CRT to display.

 

Since the BCM has never been reverse engineered such that we know how to tweak it's  program in any substantive way, problems like those seen with this car arise. One would have to either customize the BCM firmware to properly interpret the data from the new PCM, or would have to cutomize the new PCM to send a data stream that the stock BCM would recognize as being no different than  that which the stock 3800 PCM would send.

 

I think the easiest "easiest" way to overcome this would be using an interposer; a small microcontroller that would take data sent by the new PCM and reformat it to a data stream that can be read by the BCM without needing to modify the BCM firmware. Since the format of the PCM data stream is well known and has already been made to accomodate other mods, this would be much less trouble than trying to fix the BCM code. This still isn't perfect as there is no (easy) way to modify diagnostics to work with a different engine but one could use a scan tool and just forego the on board diagnostics capability  so long as basic items like engine temp and oil pressure were being monitored.

 

The other possibility would be to graft in the instrumentation from a car (Cadillac) that had a Northstar/4L80E as it's native powertrain. Then no code changes are needed, but you lose much of the essence  of the Reatta in the process.

 

KDirk

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OK, here is what it would take (if the PCM is pre-1994, 1993 Allante should work):

start with ALDLSTUFF.ZIP. This should contain both the Cad an Reatta data streams

next extract the Cad program from the PROM

disassemble

find the data stream creation area

take a Reatta .bin (ALDL data should be near end)

map the Reatta data stream to the Cad PCM. May need to adjust the RPM & MPG

 

Might help to have the car to see what works and what doesn't.

 

Of course the hard part is finding someone who understands the Motorolla 6809 processor and assembly language. Figure 200 hours and Someone Who Knows is not going to be cheap (or free depending).

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Making a Northstar "trouble free" is another issue. I am not a fan of the Northstar engine. It has been known for head gasket and bolt failures; as well as half case seal issues from the time of it's introduction. Incremental improvements in the deign lessened - but never eliminated - these problems. The only reason a Northstar swap makes any sense on a Reatta is that it is a physically easy swap, requiring a minimum of custom work to make it fit. Save for that, there are many better engines for both reliability and performance I'd choose before a Northstar. 

 

 

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Well, they took the road less traveled, and I respect that. I am a bit surprised with the amount of effort that went into it with the custom exterior touches that the engine install wasn't scienced out before doing the swap unless it showed up after it was too late? I thought the performance wasn't too bad looking but the Northstar isn't a particularly torquey engine, somewhere around 300lb/ft and probably at a bit higher rpm to get the hp. That isn't light years more than the L67 V6 which peaks at a lower rpm. I don't think it's a slouch but it would seem an L67 with a few tweaks and a smaller pulley would be a close match performance wise. Different strokes I guess.

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That is why in the 2.5-4.5 liter range I prefer a good even firing 6 with a 3.2-3.4" stroke. Much easier to tune with 120 degree pulses and has a great sound. Eights are more difficult since pulses overlap (why Ford went to the "bundle of snakes" for the Indy engine). Yes there have been big 4s and small 8s but cant think of any that were very successful at sane RPMs.

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Sound is one of the subjective selling tools as well as a very personal preference I suppose. Ford's flat plane crank and odd looking tubular manifold  are a case in point, as well as the combination exhaust with some out the rear and some out the side, not to mention piping it in via the sound system. Some like, or even covet, the uneven sound of a Harley, others, not so much. Mine has a sort of peculiar sound since the front three cylinders drive a turbocharger which knocks some of the energy out and the rear three cylinders are a bit more obvious. Sounds pretty good to me, but others???

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Speaking of sound... Do the cone shaped air filters give the 3800 a little more throaty sound from the intake? I was just out in the garage installing a new air fliter and I decided to disconnect the large rubber hose that goes to the air box and take it for a drive to see how it sounded. I thought it sounded pretty good when accelerating. Would adding a cone filter sound about the same or do they muffle the intake sound?.

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2 hours ago, padgett said:

Sounds like you need a second turbo.

You're a funny man Padgett :)  I still have my original setup which has a looser turbine A/R that uses all of the exhaust. That one goes on the 8.5:1 original engine with large intake plenum. This one is very low boost now being tried on the higher compression engine with the modified TPI manifold. Results aren't in with that yet. The low boost deal was on the 8.5 engine with the '88 cam when that screenshot in the other post was recorded.

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In the third photo of the listing is a very tasteful steering wheel with what looks like paddle shifters.  Does anyone have knowledge of what's involved in installing this into a Reatta?  I have a '91 with the electronic transmission which I'm guessing might be easier than an earlier tranny.  I understand that in the case of the Northstar, it's likely the swap also brought the newer 4T80-E automatic transmission, but I don't think GM played with paddle shifters until 10 - 15 years later with Pontiac Grand Prix's and Chevy Monte Carlo's.  Anybody?

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Certainly can be done, it is all a matter of sending commands to the trans. But why ? My Jeep has manual shifting capability but have only used to hold gears in the mountains or as a 'pre-selector".

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I have photographed moving cars, they often look slow.  Go to the drag strip, a 12 second car doesn't seem that fast, only the driver experiences the pull.

 

The video I saw was in a parking lot, the driver seemed to be concerned with the short spaces, etc.

 

What kind of times does YOUR car posts, I have a 11.02 Vette, and from side videos it doesn't look so fast. 

 

Dale in  Indy

 

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On 4/4/2016 at 6:34 PM, Ronnie said:

 

Thanks! Another project to go on my list.

 

I got the cone filter installed yesterday. I went the simple (cheap) route. I don't except much additional power. I'm just hoping it sounds good. I have the taillight out so I can't drive it yet to see how it sounds right now.:)

 

 

SAM_3159.JPG

Edited by Ronnie (see edit history)
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1 hour ago, KDirk said:

Ronnie,

Do you have a bill of materials for your install? It looks pretty good, and I'm curuous what parts were used and where you got them.

 

 

 

 

You only need two parts to do what I did. They are listed below. It is almost plug & play other than installing the IAT. The rod that runs from the radiator support to the strut tower holds it tightly in place to keep it from moving around.

 

Here is a link to my website that explains more about how I did it: Question about adding a performance air filter.

I took lots of photos make a tutorial on the installation but I don't think many people would be interested.

Spectre Performance 8162 Red Small Cone Air Filter

Spectre Performance (8738) 45 Degree Intake Tube

The filter comes in several colors.

Edited by Ronnie (see edit history)
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Might mention that the really fast drivers, the ones who can reach that 11/10th plateau, do not look fast and is a lot like driving on ice. Biggest thing I used to tell novices was not to do anything sudden because it would be wrong. Of course I was kind of a squirrel who liked to cross the finish of an autocross going backwards.

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  • 4 years later...
On 4/7/2016 at 6:48 AM, Ronnie said:

 

I got the cone filter installed yesterday. I went the simple (cheap) route. I don't except much additional power. I'm just hoping it sounds good. I have the taillight out so I can't drive it yet to see how it sounds right now.:)

 

 

SAM_3159.JPG

Ronnie, is the filter inside the original Reatta air filter box?

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