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Does an '06 Buick Rendezvous make sense for a LX9 Donor? by AAZCD
Started on: 11-02-2021 01:46 PM
Replies: 13 (309 views)
Last post by: AAZCD on 11-19-2021 08:37 PM
AAZCD
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Report this Post11-02-2021 01:46 PM Click Here to See the Profile for AAZCDSend a Private Message to AAZCDEdit/Delete MessageReply w/QuoteDirect Link to This Post
First Post here.... I'm new to Fieros and have an '87 2.8 with a bad engine (No compression on #5 and low on #6). I was thinking of a 3.4 LA1 swap, but just came across a good deal on a wrecked '06 Rendezvous with a good 140k mile drivetrain. Any reason not to go with an '06 3.5L if I was planning to do a 3400 swap anyway?
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AAZCD
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Report this Post11-02-2021 05:06 PM Click Here to See the Profile for AAZCDSend a Private Message to AAZCDEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well, I went ahead and bought the car. I figure that with the whole running car on hand I can pull most of what's needed for the swap. There's enough good write-ups here already that I don't plan to document the build here, but I'll be back reading through what's available and asking questions as it progresses.

Here's the Fiero (slightly modified by the previous owner):


and here's the donor that was a $350 Buy it Now on Copart.


The forum has been a great help already, Thanks.
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Dave E Bouy
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Report this Post11-02-2021 05:31 PM Click Here to See the Profile for Dave E BouyClick Here to Email Dave E BouySend a Private Message to Dave E BouyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Welcome aboard! I can't help you with your planned swap but good luck and post lots of pics.
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ericjon262
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Report this Post11-02-2021 07:16 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
welcome to the board. I have an LX9 going into my 85, what are your plans for engine management? the LX9 uses the same crankshaft reluctor wheel as the 24x LS1, and the stock PCM isn't exactly tunable from what I remember. MS3 and Holley Terminator have both run an LX9 with the stock reluctor wheel, and I am working on a possible option to run a earlier OBD2 PCM with coil per cylinder ignition.

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AAZCD
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Report this Post11-03-2021 08:14 AM Click Here to See the Profile for AAZCDSend a Private Message to AAZCDEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ericjon262:

...the stock PCM isn't exactly tunable from what I remember. MS3 and Holley Terminator have both run an LX9 with the stock reluctor wheel, and I am working on a possible option to run a earlier OBD2 PCM with coil per cylinder ignition.




I haven't got nearly far enough in the plan to make a decision yet. My overall goal for this car is to have it ready to run in the Grassroots Motorsports $2000 Challenge ( 2000challenge.com ) in about a year and use it for some Rallycross. Given the $2,000 budget restriction, my preference is to transfer the stock PCM from the Buick along with most of the harness and modules to keep it happy. Alternatively I could use an earlier OBD2 PCM as you are considering and run it with the swap kit from Milzy https://www.milzymotorsports.com/3500-swap/ or fabricate something similar.
The $2000 Challenge includes an Autocross course and a Drag Race. The stock 3500 in a light Fiero with built suspension should do quite well in the Autocross. For the drag race I have a nitrous kit that I ran in a Porsche Boxster ( https://grassrootsmotorspor...oxster/154304/page1/ ) a couple years ago that I hope to fit in the budget. The wet nitrous kit should work well enough with colder plugs and the stock tune.

Current suspension with custom arms and coilovers:

[This message has been edited by AAZCD (edited 11-03-2021).]

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Will
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Report this Post11-03-2021 09:07 PM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
At this point the LA1 3400 is old tech. You can have more horsepower, cheaper in a more reliable, more durable engine for the same or less money with the LX9... and the LZ4/LZ9 have just as much bang/buck with only a little bit more complexity.
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Report this Post11-04-2021 07:43 AM Click Here to See the Profile for MarkSClick Here to Email MarkSSend a Private Message to MarkSEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:

At this point the LA1 3400 is old tech. You can have more horsepower, cheaper in a more reliable, more durable engine for the same or less money with the LX9... and the LZ4/LZ9 have just as much bang/buck with only a little bit more complexity.


Agree, my LZ4 is well over 200K now as my daily driver. The coolant crossover is the item to update for a swap, other than that, shoot, a great engine. Also have a 3.6 LY7 in a Rendezvous that is crossing over 230K, this is my sons daily driver. Love to have that one in a Fiero. The Buick will be retired from daily chores when his new Subaru arrives in January.

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1965 Tempest 400 CID
2018 Chevy Colorado Z71 3.6
2017 BMW X3 3.0 T
2015 BMW 535iX M Sport
2008 G6 GT "Street" Coupe 200K miles
2005 Buick 3.6 Rendezvous 225K miles

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AAZCD
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Report this Post11-05-2021 07:36 AM Click Here to See the Profile for AAZCDSend a Private Message to AAZCDEdit/Delete MessageReply w/QuoteDirect Link to This Post
At this point, I haven't started any of the work. The plan now is to drop the whole drivetrain from the Rendezvous with as much of the harness as practical and slowly work the whole pile into the Fiero. I expect that; it's not going to fit without some modification, the axles will be an issue, the Buick harness is not going to reach places that I want it to, the '87 Fiero cluster will not want to work with anything from an '06, and the PCM from the Buick will be asking me questions that I can't answer.

I saw this on Facebook market yesterday and found it a little inspiring for the drivetrain drop:

https://www.facebook.com/ma...item/594232261696918

[This message has been edited by AAZCD (edited 11-05-2021).]

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ericjon262
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Report this Post11-05-2021 07:48 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:

At this point the LA1 3400 is old tech. You can have more horsepower, cheaper in a more reliable, more durable engine for the same or less money with the LX9... and the LZ4/LZ9 have just as much bang/buck with only a little bit more complexity.


The only important differences between the LA1 and LX9 are the sintered rods, and the oil squirter on pistons 5 and 6, not having seen a significant number of rod failures in LA1's I'm not sure it's a huge reliability jump for a production engine. FWIW, DOT Motorsports runs a LA1 3400 in their S10 that they race in a race series similar to Lemons and have not kicked a rod.

another FWIW, because LX9's weren't run in nearly as many vehicles as LA1's, they're typically cheaper to acquire, not really a reason not to run one.

I won't say it's a bad idea to run the stock PCM, but I will say it can be run on a microsquirt, which you can probably get pretty cheap if you keep your eyes out, they're less than $350 brand new, IIRC, the rules let you sell parts from donor vehicles and use that towards your budget? probably possible to take parts out of the buick and get something a little more enthuesiest friendly.

Malibus and G6's got better exhaust manifolds than some of the other vehicles the LX9's came in, more like shorty headers than manifolds, it might be worthwhile to pick a set up.

the LX9 uses a DBW throttle, the LX5 "Shortstar" V6 has a throttle of a similar size that is cable actuated, it has been adapted to the LX9 in several cases, and an adapter is pretty straightforward to make if you're handy.

I assume you're going to run the automatic trans from the buick?

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"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."

cognita semper

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AAZCD
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Report this Post11-05-2021 09:17 PM Click Here to See the Profile for AAZCDSend a Private Message to AAZCDEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks ericjon262, Good info. Let me be clear: I know almost nothing about Fieros and GM engines unless I read it here or on the 60degreeV6 Forum in the last month. I'm not a mechanic, but I can read wiring diagrams and manuals well enough to get most things working after applying enough stubborn persistence. I've had a long look at Darth Fiero's page http://www.gmtuners.com/ and downloaded a few key wiring diagrams/pinouts to look over (Awesome stuff).

My preference is to not even pull the Rendezvous transmission off the engine and install it all in the Fiero. I have not looked at the DBW pedal in the Buick yet to consider how it will mount in the Fiero. One guy on the GRM Forum just mounted his DBW pedal under the hood of a Miata and operated it with the cable pedal ( Near the bottom of this page: https://grassrootsmotorspor...-fiero/187100/page2/ ).

If the swap turns into an ugly ball of twisted wires and bent metal, I'll go to the back-up plan of a '7730 PCM and the existing Fiero auto transmission.

Learning to work with microsquirt or MS3 has been on my list of things to do for a few years, but I just haven't got around to it yet. I have learned some basic tuning with Nefmoto ( http://nefariousmotorsports.com/forum/index.php#12 ) on Audi/VW ECUs, but am still on baby steps with that. HPtuners sounds like a good tool, but I may have the wrong year of 3.5L to work with that: https://www.hptuners.com/vehicles/

The budget rules for the $2000 Challenge have a few ways to work around the $2000 limit. You can 'recoup' up to $1000 in part sold off your car or even just removed and documented at Fair Market Value. After you use up the recoup, you can trade more parts that were on the car or included in the deal. I got the Fiero for $900 with boxes of extras included, it has two nice racing seats installed and some nice wheels that I can trade out for some beater wheels. I should be able to do a lot in the $2000 budget, but I don't want to blow it all early.

[This message has been edited by AAZCD (edited 11-05-2021).]

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ericjon262
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Report this Post11-05-2021 10:48 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by AAZCD:

Thanks ericjon262, Good info. Let me be clear: I know almost nothing about Fieros and GM engines unless I read it here or on the 60degreeV6 Forum in the last month. I'm not a mechanic, but I can read wiring diagrams and manuals well enough to get most things working after applying enough stubborn persistence. I've had a long look at Darth Fiero's page http://www.gmtuners.com/ and downloaded a few key wiring diagrams/pinouts to look over (Awesome stuff).

My preference is to not even pull the Rendezvous transmission off the engine and install it all in the Fiero. I have not looked at the DBW pedal in the Buick yet to consider how it will mount in the Fiero. One guy on the GRM Forum just mounted his DBW pedal under the hood of a Miata and operated it with the cable pedal ( Near the bottom of this page: https://grassrootsmotorspor...-fiero/187100/page2/ ).

If the swap turns into an ugly ball of twisted wires and bent metal, I'll go to the back-up plan of a '7730 PCM and the existing Fiero auto transmission.

Learning to work with microsquirt or MS3 has been on my list of things to do for a few years, but I just haven't got around to it yet. I have learned some basic tuning with Nefmoto ( http://nefariousmotorsports.com/forum/index.php#12 ) on Audi/VW ECUs, but am still on baby steps with that. HPtuners sounds like a good tool, but I may have the wrong year of 3.5L to work with that: https://www.hptuners.com/vehicles/

The budget rules for the $2000 Challenge have a few ways to work around the $2000 limit. You can 'recoup' up to $1000 in part sold off your car or even just removed and documented at Fair Market Value. After you use up the recoup, you can trade more parts that were on the car or included in the deal. I got the Fiero for $900 with boxes of extras included, it has two nice racing seats installed and some nice wheels that I can trade out for some beater wheels. I should be able to do a lot in the $2000 budget, but I don't want to blow it all early.




Well, no matter how you do it, wiring diagrams will be extremely helpful to have, most wiring diagrams are available on Autozone's website free of charge, you will need to make an account though. once you have an account, go to repair help, select your vehicle, and go to vehicle repair guides, or something like that. in there you can typically find lots of useful diagrams.

Here's a few diagrams I took screenshots of for the 5 speed swap I'm doing on the Gran Damn.






------------------
"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."

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Report this Post11-10-2021 09:36 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
any updates?

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"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."

cognita semper

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AAZCD
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Report this Post11-19-2021 08:28 PM Click Here to See the Profile for AAZCDSend a Private Message to AAZCDEdit/Delete MessageReply w/QuoteDirect Link to This Post
I haven't done anything to the Fiero recently. The engine, wiring harness, and whatever else looked worth keeping has been removed from the Rendezvous. With the dashboard removed it was fairly easy to remove the harness. The only wires I cut were a couple of the HVAC servos that were being difficult to remove.


Chassis and engine harness along with some peripherals:


The engine dropped pretty easily with the subframe. I cut the lower frame of the radiator support out for easy clearance. I wish that I had removed the wheels, struts, and CV shafts before lowering it, but it wasn't too bad.
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AAZCD
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Report this Post11-19-2021 08:37 PM Click Here to See the Profile for AAZCDSend a Private Message to AAZCDEdit/Delete MessageReply w/QuoteDirect Link to This Post
Today I hauled away the Buick for scrap. It was a little tough to get on the trailer without any front wheels or suspension, but I managed to skid it on with some 4x4s.



Even with all the parts I removed, it still weighed in at 2660 lbs which got me $213 at the scrap yard. Considering that I still have most of the front end - wheels, suspension, hood, radiator, bumper... to sell, the engine and transmission along with the harness is basically free.
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