85 grand national with intercooler


I'm new to turbo buicks here. Just saw an ebay listing for an 85 GN with an aftermarket intercooler added. Can the 84-85 turbo buicks come close to having the same power as the 86-87 with an added intercooler? Also how much less are the 84-85's worth when compared to the 86-87's?
Welcome. :biggrin:
An 85 with an IC should at least equal the power of a stock IC car. Maybe the questions are;
What are your goals as in ....... how fast do you want to go and/or how collectable a car would you like to have? :confused: :confused:
To answer your questions; 1. I want to be nearly as fast as an 86/87 GN - Grand Nationals have quite a reputation, I'd hate to own a slow one and 2. I am not really concerned with collectibility - I've always liked the styling of the GN and 84-87 basically look the same. Buying an 85 would allow me to get into turbo buicks on my budget, I could always trade up to an 86/87 later on.
i saw that same buick....for teh dollars, i dunno...I would have to see the car in person to be a cecent judge on the value....If the body is straight, and everything is complete, and the car is running decent, then yeah, the money it is at right now is a worthwile investment....That is a spearco set-up, wich is nto the most efficient IC for the car, but none the less, if the ride is up-to-snuff, it can run par with a stock 86-87 GN or very close.....

If you really want a IC gn, there are always a few cheap ones, under $5 g's that are running but need bodies, or some type of physical work...as long as you can get that LC2, you can find any old regal with a sweet body to do the swap....keep the rear, the trans and engine computer/harness, and that is the $5 g's right there!

I am currently trying to build a low 11 sec hot air with NO IC....At the rate adn cash flow I have so far, the car is not moving, and at this point in my life, I just want a running TR to begin with.....BUT....for a total investment of under 7000, I can have that 11 sec car, including NO IC!!!!

cost of my car when I got it was real cheap...2000

turbo 800 injectors 200 roller set-up 2000 forged engine from a friend 600, alky 400, and all the otehr odds and ends, including 600 dollar heads and intake combo, set me right at 7 grand.....can you find an 11 sec 87 GN for under 7 g's?

It is all up to your goals, your wants, and your budget

Good luck! let people around you or near you help look at the car and figure out if it is a good deal....dont buy it just becuase it is a real T-Type or GN....you can go and get any regal and find a transplant for cheaper...but, if it has what you want, and is ready to go as you like it, then for the price, i think it is a good investment, or at least a good start!!

With just an intercooler, I went 13.9@101mph at stock boost levels (13psi) and street tires. That's about right for a stock 86-87GN.

The big differences are the 87 has a bigger turbo, better downpipe, and better intake manifold. When you start modding, you will have to upgrade the 84 turbo to go faster than high 12s and it would make life easier even if you wanted mid 13s to go ahead and upgrade. I got to 105mph trap speeds with the stock turbo and broke two of them before I finally upgraded.

The intake manifold will hold you back in stock form but it flows plenty of air once it's ported.

The downpipe/uppipe/passenger header would be one of the first mods on the hotair cars vs one of the last mods on the IC cars.

My car with a small turbo upgrade, intercooler, ported intake, and headers/downpipe went 12.9@110mph on pump gas and no alky. That's about right for an 87 with the same mods on low boost. I had an exhaust leak and couldn't get off the line very hard or the ET would be much better but the mph shows the power was there for low 12s.
With my 85 the only mods I have done to it are a chip, straight thru exaust(no cat or mufflers), and a K&N air filter. I was able to run a 15.8 in the quarter mile on about mid grade pump gas, and on street tires, at a track that is over a mile above sea level. I even spun the tires for about a car length and a half off the line before I finally hooked up. You take that down to sea level and throw on some slicks and I bet you could run low 14's with the same setup Ive got, and the cost of those mods and a hotair Regal are no where near what it would cost to get a stock intercooled vehicle.
Thanks for the replies. The 85 GN has sold. I have found an 84 GN 4 hours away from me, he is asking $2500. The car has faded paint, a few dings, and the interior is shot but he claims it is mechanically sound and there is only a slight amount of rust on the underside of the doors - otherwise rustfree.
I would rather have a car that was better mechanically than cosmetically. Its a lot easier I think to fix the cosmetic defects than to rebuild the engine and tranny.
The 84 is the most collectable because there were only 2000 made. There were tens of thousands of the 86-87 turbo cars made. They were the fastest American production car for all four years they were made. The 84-85's clean up on more than 90% of performance cars up into the late 90's. At the prices 85-85 cars are getting now, I don't think you can go wrong if you plan on keeping it. The only way you can get a slow one is if you get one that is in bad shape/tune. Performance bang for the buck doesn't get much better than the 84-85. The last one I saw on E-bay went for 5000. I think the prices will be going up soon. Danny Here is mine getting intercooled.
I have kept mine hot air for 16 years, and have put to shame many "race cars"on the street, and at the track. I have installed/ fabricated turbo/IC systems on lots of other peoples cars. I came up with an idea about where to put a IC on GN's, and decided to do the fabrication on my own car. What you have done with your hot air is great example for the hot air guys to show just how to make these cars scream. Mine was capable of high 12's at 5200ft elevation with the stock turbo, and very little money. Now I am at 7000ft. I think my baby deserves an IC. Later.....Danny
They were the fastest American production car for all four years they were made
not true. even the 86/87s stock were running the same times as the L98 Vettes of those years (high 13s - low 14s)

the 84/85s were about a second slower than that, while the 85 Vettes were the same high 13 - low 14 sec cars that the 86/87 Vettes were. even the TPI 305 Fbodies from 85 were able to match the low 15 sec times of a hotair GN
I wouldn't want to argue about it. You must know more than me about it. I have never had any trouble with any of those years of cars though. Danny