87 GN Performance questions


I just took ownership of my first GN and have some questions...

I have some concerns after much reading here that I may have too much Boost..... The mods that I was told that are on the car and I believe the information to be correct is as follows.

Waldro pump and wiring harness
adjustable regulator
adjustable waste gate rod
K&N filter and aluminum Kirban I think maf pipe and GM Maf
Stock injectors
Has distribution plate from Kirban I think between the upper and lower pleneum.
Jay Carter street chip.

Anyway .. THe car runs great on the road got 25 mpg and on mild throttle application about 12 psi it shoves you back decent for that type of throttle position... However like passing from 55mph floor it and it downshifts and revs the turbo is whistling, but it just does not feel like its pulling that hard.... I don't hear pinging but the car has no mufflers so it's kinda loud....
Boost is hitting 19 psi running 93 octane fuel...

Also is it normal that you can nail it from a dead stop and it will not spin a tire unless you hold it on the brakes and build 4-5 psi of boost? I may be spoiled by my 2nd Gen Trans am with aluminum head 455 cid engine and 5 speed that will destroy the tires from a 40 mph roll instantly though too.... I just feel the GN should be running harder... I am thinking I need to extend the rod on the wastegate 3 or 4 rounds and get the max boost down to about 14-15 psi.... maybe it is retarding timing.... Normal driving is fine. I would like to get the GN to run mid 12's one day ... I think 13's might be possible from my SOP impresion right now .....

Also at wot does the computer disengage the AC compressor and cut the charging circuit on the alternator to reduce load ?

If you have not done so get a knock sensor, and a scanmaster. Then it will be much easier to dial in your car and avoid overboost....:biggrin:
I think 19 psi is pushing it with the stock injectors, a good set of 50lb'ers and chip to match should be your next upgrade.

Second concern is normal for these cars as the turbo doesn't come in right away ("turbo lag"). with traction, a good downpipe and exhaust 12's should not be a problem

I know the a/c is disengaged at WOT, not sure about the alternator
First and foremost I want to echo benoitthegr8r's reply:
Get a Scanmaster immediately (an absolute necessity!) and a knock gauge (I have a Casper's LED-type) PLUS....
Are you basing your boost readings on an accurate analog boost gauge?
If not, get one.

19 lbs. is a lot of boost on pump gas and stock injectors.
Not sure how old your Jay Carter chip is?
I'm tickled to death with my Turbo Tweak pump gas chip.
It's the latest and greatest and Eric is positively awesome to deal with.

Speaking of the lag issue.....think of it this way-it gives you a chance to launch with less tirespin while that pesky LS1 car is fighting to get out of the hole without annhilating his.
Then REEL him in. :D

Welcome to the wonderful world of turbo Buicks!
They can be fussy as hell sometimes but when they run good....look out! ;)

Prioity 1! A scan tool and knock detector. the knock detector, either the visual or the audible works great, I have both. If you opt for the scanmasterII, you will be able to upgrade it to Mike's power-logger at a later time, where you will be able to collect data needed for fine tuning and trouble-shooting. you will also be able to add the lc-1 to read A/F in real time.

The 19#'s is way too high w/o the ability to monitor it and it can hurt the bottom end. take it back to the stock #'s. once you have it running correctly, the addition of an alchy kit will make it economical to take the boost to new levels, safely. I would imagine the knock is retarding your timing, and yes, at wot, the a/c and alt. are disengaged.
No, you should be able to nail it from a dead stop and spin the tires, even my 83 carbed version was cable of that.:biggrin:
Ok what is stock levels for this car ?

about 16 ?
I assume I make the rod longer on the waste gate and test until Its down some?
I read on another site about 1 round for a psi... IS that a good start ? Take 4 rounds out on the link and try it ? Maybe 14 to 15 psi boost on the Pillar gage.

I will probably invest in the scan tool as $$$ Allows... I am just interested in getting the AC recharged and the headliner install so I can enjoy driving the car around some, but I don't want to hurt anything playing either, but still want it to feel fast and not like I'm driving a poser and fearing everything I line up with at a stop light LOL.

Seems like every new car has 300+ hp now.

Thanks !
I have a pump gas chip from Turbo Tweak and it's range is 15-17.

If I were you, I'd go 14 and drive it like that.
Better safe than sorry until you get a scan tool.
Once you get one, you'll be shocked at all the info it gives you.
Until that time, err on the safe side and just drive the car.

As for the A/C.....I guess you'll have to convert to R134?
R12 is gold these days if you can find it. Dumb.

My local upholstery shop does our sort of headliners all the time.
It shouldn't be expensive at all.
The G-body is notorious for junk headliners.
They fall and look terrible.
If your gonna step up and own one of these cars... Do this. Get a Turbotweak chip, 009 injectors, alky kit and some good tires.;)

That combo with stock turbo and IC will net you low 12's all day long at 22-23 psi. Once you lock in your tune with your scanmaster your done. Enjoy your Turbo Regal.:smile:
If you can't afford $250 for the Scanmaster, spend $80 on a Casper's knock gauge or at least get a cheap boost gauge from Summit so you know what's going on. The stock gauge isn't very accurate. I wouldn't "play" with your car until I got some way to know what's going on under the hood. You can easily hurt that motor and cost yourself $hundreds$ in repair costs.
I know a guy that is heavy into the turbo Buicks... he is sort of a friend of a friend .... I hope to talk to him tomorrow. I hope he will help be tune the car one weekend with a scan tool.... until then I'll back it down to 14 or so .

I don't know about most of you guys.. but money is tight and I really went out and bought this thing to complete a dream.... it was not the best time... I just ordered a new Headliner 200 bucks and plan to recharge the AC with R134... next week... It still has enough R12 to blow out the valve though... at least I don't need a dryer I guess... Do you think the new chip is noticeable better than the JAY Carter Street chip in the car now ?? If so I'll spring for that next.

I also need mufflers what is a good center in and out muffler 2.5 " pipe.
I fully understand that money is tight. That is why I offered several options. These cars are 20 years old and can become moneypits. How do you know what the boost level is?
It has a pillar mount Gage I am referencing... autometer I think.
Dash leds peg out as well.

I am dreaming a bit I think, but backing the boost down and just driving it around is my best option for now, however, I want to study it and learn as much as I can so when I can dive in I do not make a money pit out of the car..... I don't have the finances to do that so I have to try and be smart about it and realistic. I can see a mid 12 sec car is about as fast as I can afford I think. Car must remain reliable and as stock like as possible. I purchased this partly for my wife ... She is scared of the Trans-am ( too fast and violent ). The buick I think can be quick and still feel comfortable for her to drive around.

So far I see a Razors alky kit ( must run on pump fuel don't care to mix race gas )
A new Chip...

Id like to retain the stock Turbo,IC, and Injectors if I can...

I will check into a knock sensor... where is a good place to mount that ?
Id love to have one I could put in and take out after I got it lined out. Maybe even use it on the TA as well...??

I hope it works out I can borrow a scan tool after I make mods on a track day or is that even feasible as I don't know how they hook up... I am assuming its a plug in device to a service port... I don't want a little box setting on the dash all the time really. I like it to look stock in and out.. under the hood I am ok with a little racey look.

I am excited about the car... I was getting a little board with the old TA ...big cubes NA... Torque out the butt though.... Runs mid to low 11's fwiw. I hope someday the GN can put me in the seat sort of like it does though. I thought these cars were pretty easy to get in the 12's .... That would be fast enough I think. I hope to learn enough in the next 6 months or so to decide if I want to keep the car long term. I told myself hey these cars are holding there value or maybe even appreciating it only has about 55000 miles is super clean in and out top and bottom drives great looks mean as heck and if things get tight $ I can resale and recover most of my investment anyway I hope. I have just always wanted one of these cars since they were new. I was 19 and watched a 86 spank a new corvette in a street race.. I had never drove or rode in one though until I purchased this one. I was not real impressed with the performance but the car looked great and ran decent.. I just told myself it had potentail and it was a 87 and cars were not that quick in 87 compared to today just like my 77 TA stock was slow compared to late model F-body ...

I am running on... excuse me. Just trying to convince myself I made a good choice. I know what it takes to make a v8 run 12's like my Ta that was easy.. and pretty cheap. I was hoping to do the same here... Moving the TA to the 11's was much more expensive... I expect the GN would be the same....

Thanks !
Good idea!

Your pillar gage offers you some truth about your boost level, and one psi /turn on the adjustable waste gate. If you find that turning the adjustment rod back does not work, you may have a heavy duty w/g and it may not go below 18#.(mine starts @ 14#)
I just had my headliner replaced about 2yrs ago and I paid 130.00. The TT chip probably would be noticeably better, depending on how old the JC chip is, technology advances every day, but the knock gage will give you piece of mind. A bad tank of gas can cause head aches. At least w/the k/gage you will be able to see how far you can push it and not damage anything.:eek:
Many of us on the board understand the tight budget, and for many it seems like an ongoing problem, but we have a really good community and try to help each other as we can. and if that friend of a friend is a member of one of these boards, he should welcome your aquaintance readily.:biggrin:
For the muflers, I hear hooker offers a good deal thru summit I believe, a cat back system for around 250.00. do a search and it should reveal the details.:cool:
THe cat back is about 360 now I guess checking Jegs and Summit.... I am thinking about getting the Hooker Aero-chamber center in center out mufflers 73.00 each and putting them in myself since the pipes and everything are like new under the car and there is a straight section of pipe about 19" long I think I can cut in the mufflers without too much trouble.

Whats the key getting these car to run... It is making boost 16 to 19 psi.... what would a bigger TC do for it without changing internal parts or just going higher boost wise which is not possible with pump gas ?

I always heard 12 were easy with these cars with minimum changes is this just advertising or fact ?

Id like to make a honest 400 rwhp one day on pump gas, and another thing the car seems to really lay down over 4000 rpm. Is this normal ?

Thanks for the help !
IMHO, don't waste money buying those small injectors. Go straight to the 60's. They work great on even a bone stock motor... and give you plenty of growing room. Definately get a matching Eric Marshall chip... and a scanmaster... and an audible knock detector. I prefer audible.

I agree with others... boost down first.... then audible knock detector... then scanmaster... then injectors and TT chip. They could be done in that order... just remember the injectors and chip must be done together.

If you read alot on here... do the general "spring cleaning" stuff found over at gnttype.... you will be on your way to a reliable low 13 sec car....

A few bolt-on parts more... and some more boost.... mid to high 12's are easy on a stock turbo...stock unopened motor.....with pump gas and alky....

Read alot.... and take advice from the people that have been where you want to go....

Welcome to the club!
Whats the key getting these car to run... It is making boost 16 to 19 psi.... what would a bigger TC do for it without changing internal parts or just going higher boost wise which is not possible with pump gas ?

I always heard 12 were easy with these cars with minimum changes is this just advertising or fact ?

I'm in the same boat as you, I just purchased a Turbo Regal about 2 months ago. This being my 4th Turbo Buick, I know getting them into the 12's w/o spending a$$loads of money is possible. You can get the car into the 11's on a stock turbocharger, but this is almost always the exeception. Proper fueling, letting the motor breath, and tune, tune, tune is the key. Basics are: K&N, bypass breather kit, torque strap, 160 thermostat, RJC powerplate, 340 Walbro, hotwire kit, MSD 50's, Adj FPR, 3" downpipe, Duttneck, Ported TB & Plenum, Alky, MT street radial, and Airbags. That set up with proper tuning tools would easily get you into the 12's, a larger turbo with the above build could get you into the 11's. hope that helps...All the above mods exept the Tires added up to about $1850, most of that price being tied up in the alky and downpipe. If you want you can email me and I'll send you a cost analysis spreadsheet that I came up with, it tells you which vendors are selling the above item's cheapest...:D