what have I got?

[deputydawg]

I bought my 87 GN a few months ago and discovered it has had a hard life. Bent frame I just paid to have straightened, tweaked body poorly repaired, decent interior, a bastard rear end, but the AC works good.

My question is what exactly has been done to it. The individual I bought it from told me the engine has never been cracked open, but I see alot of after market parts. it has a cold air intake, big ass downpipe, dump and a 2.5" hooker exhaust ( I installed ). I have been told it has an Art Carr transmission with a stall converter and a performance chip. Is there someone in Houston, Tx area that can go through and let me know which chip was put in, and what has been done? The car kinda surges at idle, this normal? I am beginning to think it would be best to rebuild the motor as there is no telling how many and what kind of miles are on it.

I have always wanted a Grand National and The price wasn't too bad. I am hoping to have the body work taken care of in the next few months (replacing quarter panel, shaving door handles, locks, antenna, mirrors) and then move on to ditching the stall converter for a stock one, rebuilding the suspension (ball joints, bushings and tie rod ends), installing the correct rearend and installing air ride.

 

[ES1]

Get the numbers off the injectors and check www.gnttype.org to see what they are.
Pull the chip and tell us what information is on it and maybe someone can identify it.
If the engine compression is good, leave it alone.
Many high mileage cars that still run good.

 

[deputydawg]

here is what I found out...

The chip says Hypertech SR# 0010415, PT # 41371. After a little googling, it is a 10-15 hp/ 20 ft/lb torque chip.

The injectors have 0280150967 on them with 5/69 in the upper corner.....again, after some googling, they are 36 lb units.

With the cold air intake, 3" downpipe, dump, 2.5" hooker exhaust, is this a good combination of upgrades?

Any suggestions? I am not looking for a quarter mile monster, just a nice cruiser that I can play with every once in a while......

 

[jdpolzin]

Do you know what turbo is on it? What is the stall speed of the converter?

 

[Quiky One]

Get a new chip from Eric Marshall. www.turbotweak.com. Make sure you find out what turbo it has before you change the stall. Do you have a scantool? If not get one before you make any passes or floor it. A scantool is vital.

Jason

 

[Quick6'n'-K.C.]

If you shave the door handles, you will never be allowed to race at a race track....
Is there something wrong with the door handles

BW

 

[deputydawg]

nothing wrong with the handles

I am not going to run it at the track, no desire to race. I have no idea which turbo is on it, is there an easy way to find out?

 

[Quiky One]

Take a picture of it and post it. What does the housing say? Any numbers on it?

Jason

 

[jdpolzin]

Probably your best bet is to take some pictures and post them so we can try to help you a little more. The reason you need to know what turbo you have and find out what your stall speed is because the two intertwine with each other. The bigger turbo you have, the higher stall speed you need your converter to be. Do a little researh and post some pictures and you'll be able to start identifying what you have and how they work together. If you aren't going to build a fast car and just use it for cruising, you might be better off getting a GN that has not been modified. These cars a very particular and each component makes a big difference in tuning. Good Luck!

 

[Quick6'n'-K.C.]

ta is the stock appearing with the inlet bell bolted to the compressor
te does not have a inlet bell..

Do you have a picture of your turbo?
BW

 

[Lee_Burough]

Many GN's still have an unopened block and heads with the bolt-on modifictions you listed. Without some definite information pointing to a real need to overhaul the engine, I'd wait....

The modifications you describe should make a good car for the purposes you describe. Personally, I'd want a lock-up converter, you might want to check into that.

Get a new chip and a scan tool, then an Alchy kit.

 

[deputydawg]

pic

Here is the only pic I have. I am waiting for the camera to charge so I can take some closer ones.

 

[deputydawg]

injectors?

Are the injectors stock or upgrades @ 36lb?

 

[Quick6'n'-K.C.]

Has the original stock turbo ta inlet bell, check to see if the bell has been bored thin to match the inlet of the compressor housing.

That actually looks like a stock turbo, possibly take the inlet hose off, take a pic with the ta inlet bell on and i can go from there.

Direct shot straight in would do just fine...

BW

 

[deputydawg]

as soon as the camera is charged....

That is an old pic I took when I first got the car, but I have changed nothing. As soon as the camera is charged I will get some more pics. I really appreciate all the help. So if it is a stock turbo.....with all the other upgrades, would I be better off upgrading the turbo if the compression is fine on the motor or just upgrading the blow off valve and intercooler?

 

[Lee_Burough]

Some free advice....

I'd recommend you resist the urge to modify your car right away.

Give it some time and I'm sure you will change your mind from some of the things you posted initially....Your modifications are a bit dated, but still good ones (with the stall speed of the converter a big question, but not urgent).

These cars came with 28 pound injectors, so the 36 pounders are not original. Do you have any hints about a fuel pump change? That may be the next priority after a scan tool.

I did mean to mention that stock and early performance chips caused/allowed the idle RPM to hunt (what you were calling 'surge')....Was normal for this engine. A modern chip will clear that up completely.

Sometime you may decide that the intercooler is a hinderance....A 'big neck' intercooler modification will flow 20% more air than stock. I'd try that before buying a bigger intercooler.

Your first priority should be to choose, and master, a scan tool for tuning.

 

[Quick6'n'-K.C.]

Dang Lee, your on it tonight!

Im gonna sit back and watch the end of braveheart and leave it to Lee Burough.. He seems to be right on it, and very pleasent.

Keep it stock till your in the 12s, go from there IMO

BW

 

[Lee_Burough]

Dang Lee, your on it tonight!

Im gonna sit back and watch the end of braveheart and leave it to Lee Burough.. He seems to be right on it, and very pleasent.

Keep it stock till your in the 12s, go from there IMO

BW

Bryan, I'm just lightening your load here ....You know ten things for every one thing I know about these cars. I always read your posts carefully.

 

[Ormand]

Is there someone in Houston, Tx area that can go through and let me know which chip was put in, and what has been done?

Try Conley, in Humble, Texas. Here's a link;Conley's Buick Performance These folks know how to get a Buick to run.