New owner of an 86 GN

mblum

New Member
Joined
May 23, 2021
Hello all, I recently acquired a 86 Grand National from a family member. I have always been a V8 guy and had never been around turbo Buicks in the past, at least not first hand. I remember seeing them at the drag strip quite often and remember most of them being fairly quick, but just never caught my attention I guess. Fast forward 20 years and I had a chance to pick up an 86 GN I started researching them and quickly realized that this car was something I really wanted. I'm fortunate to have a few other performance cars and the GN was a perfect addition, just simply how uniquely different it was from the others.

The car has 89K on the clock, and I think that is accurate and not 189K . The car has only been driven about 200 miles in the last 10 years. The body is in decent shape and after spending about a half hour under it I could only find a few small rust bubbles, which I'm totally fine with being it's a Midwest car. The interior is in very good shape for it's age, after an afternoon of deep cleaning I was very surprised how good it looks. I don't plan to change much interior wise other than maybe window tint down the road. The bumper fillers were falling apart, which I have already replaced with Spool Fool's front and rear fillers.

The only mods on the car that I have found so far are a scanmaster, AFPR, aftermarket boost gauge, coolant temp, and oil pressure gauge. The cat has been removed from the exhaust. Someone moved the battery to the trunk, not sure why....

Under the hood is where I have some work to do. I've been doing a ton of reading on what to, not to do, and what to look for and for now have stopped driving the car.
I have already changed the fuel filter, spark plugs, and the oil.

The issues that require immediate attention that I have found so far are:
-Leaky valve cover gaskets, they leak terrible and are making a huge mess not only on the ground but down the engine and exhaust (smoking from under the hood).
-Leaky injector o-ring, intake manifold side, rear drivers. ( think this has progressively gotten worse and is the main reason I have stopped driving the car)
-The turbo appears to be leaking oil into the MAF pipe. There is a noticeable amount of oil pooled up at the coupler and covering the MAF. For the time being I plan to re-build the stock turbo.
-Leaking master cylinder, someone has already changed to a Vac setup, I just need a new master.
-Fuel system appears stock and I have plans to drop the tank, replace the pump and install a hot wire kit.
-The car appears to have the stock chip in it yet. I can't make out much on it but I can see "DELCO CMW" on the top and "JT8(B)/AJ30/P" on the bottom. Upgrading this to a TT chip is on my list.

I am considering replacing the stock MAF with a 3.5" F-Body LT1 unit with a translator. I happen to have a spare one that is in great shape that I can use.

I'm sure I will have a lot of questions, but so far I have been able to find a ton of info on this site, which is awesome I might add!
 

mblum

New Member
Joined
May 23, 2021
Is there any harm in running larger injectors at or near the stock power levels if I do TT chip?

Once I get the obvious issues I have found sorted out I would like to focus on making more power, so I had considered increasing the injector size that would support future mods. Down the road I am considering an upgraded turbo, 3" down pipe, alky. My goal is roughly 450hp, what size injectors would support that HP?

Not from Peoria, I'm in western Iowa, right across the river from Omaha NE.
 

RED LS1

SENIOR MEMBER
Joined
Dec 31, 2001
Get the chip and inj combo. You can do 60lb inj with his chip and the car can be completely stock. That will also give you the opportunity to do future mods if you wish. Once you have the chip in you will be able to use that with the scanmaster to dial in the way the car runs at WOT also.
 

1986 Buick GX1

GX1 #001 [The One and Only]
Joined
Apr 24, 2015
Welcome to the best TR hangout.
There’s a good spring cleaning guide and maintenance tips at gnttype and vortex buicks.



Fun fact: Us ‘86 GN guys have a 40.2 lb weight advantage over the ‘87 GN guys due to our aluminum bumper reinforcements vs. their steel ones (according to info on this site.)
 
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mblum

New Member
Joined
May 23, 2021
Thanks for the info, I had found the spring cleaning link and have been following the info there. But I had not found the Vortex Buicks link, lost of good scanmaster info there, I was wanting to find something like that that has a good description of each display.
 
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