1985 Hot air converted to Intercooled

#6
In retrospect, I'd have to agree with 65psiboost. I have an 85' that has the 'guts' out of an 87'... I bought the car this way, but to me it just doesn't make much sense to do the swap UNLESS one had a wrecked/rotted out intercooled just sitting around. I got a pretty good deal on mine although I don't think I would take an intact Hot Air car and defile/de-value it by modding it in this way nowadays(15-20 yrs. ago I'd have thought differently tho). Throw an Alkycontrol meth injection system on that baby and be pleasantly surprised by how much she'll "wake up"... and if you just can't be happy with that, sell the car(they're pulling solid $$$
 

NY Twin Turbo

All the good stuff.....Times 2.
#7
Does anyone have a list of the part to convert from hot air to intercooler?


Thanks for everyones help.
You need to have both cars sitting along side each other. Gut the 85. Install the 87.

Mine was converted over 20 years ago. We used an 87 GN that was badly T-boned at an intersection for the donor. The only thing we didn't swap was the powermaster, driveshaft and rear. My 85 was built in late '85, so it already had the powermaster. The rear and driveshaft are the same.

Seems crazy these days. Because today, it's so far from stock I shouldn't even have bothered.
 

NorCalTurbos

Slowing down to SPEED UP!!!
#8
Cost me around 4k when I did mine. I bought a complete motor and trans for 3,500 it showed up with a smoked turbo :mad: Btw thanks and :finger:Dan....
I have an 85 that I’ve owned for 16yrs, so I doubt I’ll ever sell it to me it’s priceless, no matter if I have the HA or the IC setup it’s priceless to me.
The main reasons for my conversion was the upgrade parts availability also maybe it’s just me but I’m always doing something to my car and to be honest it’s seems like everytime you need to do something the turbo has to come out, with the ha motor.
It’s all about you and what you want with your car.
 
#9
Cost me around 4k when I did mine. I bought a complete motor and trans for 3,500 it showed up with a smoked turbo :mad: Btw thanks and :finger:Dan....
I have an 85 that I’ve owned for 16yrs, so I doubt I’ll ever sell it to me it’s priceless, no matter if I have the HA or the IC setup it’s priceless to me.
The main reasons for my conversion was the upgrade parts availability also maybe it’s just me but I’m always doing something to my car and to be honest it’s seems like everytime you need to do something the turbo has to come out, with the ha motor.
It’s all about you and what you want with your car.
Thank you . I' still trying to decide what to do to my 85.
 
#10
Thank you . I' still trying to decide what to do to my 85.
I really should've been a little more clear with what I meant by 'defiling' your HA car. I think(and it's just MY opinion) if you have a really sweet example of a 1985, in very nice original, or even almost original condition car, you may do better to just sell the 85 and find an 86 or 87. I have seen folks ask a lot for nice ones around my area(So. Fla.- so everything is overpriced LOL). Damn close to what IC versions go for. Not sure what they get for them but it does seem the 'overpriced' intercooled years sit A LOT longer on CraigsList, etc. All I'm trying to say is you have a ton of options, and unless you're a guru of Turbo Buicks, swaps can and often do get tricky. Heck, I still am at a loss for what the few extra wires under my hood that just 'exist' but aren't plugged in to anything actually used to go to(guess if I actually did the swap I'd know, maybe...). Either way, do what YOU feel comfortable with doing- whatever makes YOU happy, and you'll be OK
 
#11
I did the conversion and it got out of hand with all the mods I ended up doing , you should consider pricing out an LS conversion turbo , if you want to do HP /Per $ comparisons . You can find pull outs of the 87 motors and trans under three grand that are mostly stock. The mods are what really start running up the dollars so have in mind the goal of how fast you want the car and its purpose to help guide you.
 
#13
The only way it's worth doing in my opinion, is if you're doing all the fab work yourself because you enjoy it. It can be done properly for not a lot of money if you're building it yourself like I did mine. Biggest thing is that you don't want to have the throttle body mounted on the turbo as it is now, because it turns the turbo and all the charge piping/ intercooler into one huge plenum that sees boost AND vacuum. Transitioning all that volume from vacuum to boost is one major reason all the cheap bolt on kits made back in the day got such a bad reputation for killing throttle response and creating massive amounts of turbo lag. I still used the hot air intake, and welded an elbow to it to mount the TB, and my throttle response is identical to my wife's uncle's '87, although mine is faster once boost builds ;) He's still 100% stock.
 
#14
The only way it's worth doing in my opinion, is if you're doing all the fab work yourself because you enjoy it. It can be done properly for not a lot of money if you're building it yourself like I did mine. Biggest thing is that you don't want to have the throttle body mounted on the turbo as it is now, because it turns the turbo and all the charge piping/ intercooler into one huge plenum that sees boost AND vacuum. Transitioning all that volume from vacuum to boost is one major reason all the cheap bolt on kits made back in the day got such a bad reputation for killing throttle response and creating massive amounts of turbo lag. I still used the hot air intake, and welded an elbow to it to mount the TB, and my throttle response is identical to my wife's uncle's '87, although mine is faster once boost builds ;) He's still 100% stock.
Yes sir! Best thing I ever did to the car after intercooling it was move the throttle body. If you have a welder and some basic fab skills it’s not hard to intercool a hot air car.
 
#16
Is it absolutely necessary to have a 1986 harness to do this swap or can you use the 1985 harness?
Specially since my car is already converted to 1986 ECU.
Are we talking length being the problem for the harness or what?
 
#17
The only way it's worth doing in my opinion, is if you're doing all the fab work yourself because you enjoy it. It can be done properly for not a lot of money if you're building it yourself like I did mine. Biggest thing is that you don't want to have the throttle body mounted on the turbo as it is now, because it turns the turbo and all the charge piping/ intercooler into one huge plenum that sees boost AND vacuum. Transitioning all that volume from vacuum to boost is one major reason all the cheap bolt on kits made back in the day got such a bad reputation for killing throttle response and creating massive amounts of turbo lag. I still used the hot air intake, and welded an elbow to it to mount the TB, and my throttle response is identical to my wife's uncle's '87, although mine is faster once boost builds ;) He's still 100% stock.
Mind sharing some pics? Curious on how you mounted the TB
 
#18
I don’t know if the thread is still active but I have a few questions for the ones that done the conversion. I have a 84 gn and installed a 86 intercooled setup my only problem is the fan relay not getting power from the fan fuse because 84-85 gn didn’t have electric fans. Without changing the whole fuse panel how can I get power to these relays?