General Maintenance questions.

[JakeM]

Hello - As you may have read in the introduction forum, my nephew just got a 1986 GN. It appears to be in great shape, however I have only seen pictures and haven't gotten my hands on the car yet. Keep in mind I'm a fairly experienced mechanic and I'm not new to high performance vehicles. As far as I know the car is all stock besides a shift kit and has a new turbo, or rebuilt turbo. Either way its OEM. We don't want to start getting into performance mod's yet, but we would like to bring it up to its maximum potential with what we have.

My questions are:

What should I be looking for on a 1986 GN with 110,000 miles maintenance wise?

Should we replace the factory fuel pump if its the stock one that was in the car? If so, what is recommended? In my limited reading here, I have seen a lot of mention of Walbro 340.

As far as tuning options, what is the best for a DIY setup? I am SCT trained and have a good bit of experience tuning EFI. This isn't something we are looking to do right now, but it will most likely come to the point where it needs a tune. Would it be cheaper/better to pick up a pre-programmed chip from TT?

What else should I be looking for, assuming everything is stock and has 110k miles on it?

I'm assuming the exhaust is going to need going over, this is a Iowa car but has little rust. But it would be a good bet the exhaust is ready to go. What is the best option as far as Down pipes? Preferably catless. The rest I can have done at our local exhaust shop for a good price.

Lastly, what tire size is recommended for the stock wheels? So that I don't mess up the speedometer. 255/60 rear 235/60 front for a daily driver?


Thanks,

Jake

 

["Turbo-T"]

Yes, replace the stock fuel pump...and the pump sock too. Also add a fuel pump hot wire to the fuel pump.

Yes you should go ahead and upgrade the chip to a Turbo Tweak, unless it already has one in it. Also add to it a Scanmaster so you can take advantage of the TT's tunable features plus monitor the engine for KR and such.

The valvesprings, if not replaced, should be looked into.

A spring cleaning should also be in order.

The stock downpipe is good into the 12's. But if you must replace it, a Terry Houston 3 inch DP is a good one, but can be hard to find since they're not made anymore. There's a few others that sell aftermarket dp's (RJC, Gbodyfarts, etc)

Tires...215/65 is stock, but ok, if you want to go wider than stock, 235/60 is about as close as you'll get w/o throwing off the speedo too much.

 

[JakeM]

Ok. When replacing the pump to something bigger its going to need to be chipped at the same time, correct? Also, just so I'm clear, a 1986 GN is Speed Density correct? Or have I been misinformed?

 

[turbofrank]

If stock rims 245x60 rear max anything larger expect uneven wear. Fronts do the search i use stock size tire.

walbro 340 or Reds pump both are PP

If car has 110k timing chain soon.

check turbo regal website Turbo Regal Web Site
visit spring cleaning and recipes and other topics.

 

[williamsGN]

Gnttype.org as mentioned above, especially

The Grand National / T-Type / Turbo Regal Buick Spring Cleaning Guide

The Turbo Regal Buyer's Guide

Don't need to update the chip to replace the fuel pump (though it doesn't hurt so you can take advantage of the bigger flow of the new pump) and pretty sure 86 isn't speed density.

 

["Turbo-T"]

Ok. When replacing the pump to something bigger its going to need to be chipped at the same time, correct?

The only time you need to change the chip is if you change injectors or if you still have the stock chip. The old stock chips were designed for 1986. The new TT chips are designed for today.

 

[nickygn]

no,to speed density. mass air flow unless it has been changed to a translator pro or xfi which i doubt because you said it's stock for the most part.

 

[CaptainInsane-O]

My questions are:

What should I be looking for on a 1986 GN with 110,000 miles maintenance wise?

Should we replace the factory fuel pump if its the stock one that was in the car? If so, what is recommended? In my limited reading here, I have seen a lot of mention of Walbro 340.

As far as tuning options, what is the best for a DIY setup? I am SCT trained and have a good bit of experience tuning EFI. This isn't something we are looking to do right now, but it will most likely come to the point where it needs a tune. Would it be cheaper/better to pick up a pre-programmed chip from TT?

What else should I be looking for, assuming everything is stock and has 110k miles on it?

I'm assuming the exhaust is going to need going over, this is a Iowa car but has little rust. But it would be a good bet the exhaust is ready to go. What is the best option as far as Down pipes? Preferably catless. The rest I can have done at our local exhaust shop for a good price.

Lastly, what tire size is recommended for the stock wheels? So that I don't mess up the speedometer. 255/60 rear 235/60 front for a daily driver?


Thanks,

Jake

These sites will help get you familiar with the basics:

Vortex Buicks

Turbo Regal Web Site in particular, check out the Spring Cleaning guide... The Grand National / T-Type / Turbo Regal Buick Spring Cleaning Guide

Definitley want to replace the fuel pump, they were barely adequate when new. Racetronix can set you up with a good pump & hot wire kit (ensures the pump gets plenty of juice.)

Tuning wise, there are several stand alone options out there but for a near stock car that'd be big time overkill. A Turbo Tweak chip offers user adjustability, you can just order one with the car's exact combo & dial it in from there.

Exhaust, I have the 3" Torque Tech system & have been more than happy with it. Hooker & Pypes are also popular choices. I'd stay away from the local shop unless they'd be piecing a system together for you out of section of mandrel bent pipe. With a forced induction car you want as little exhaust restriction as possible.

255/60/15 tires will fit fine on the back but they are about 1" taller than the stockers so the speedo will be a bit off.