Got beaten by a GTP!?

[JimBlackGN]

My 90k miles '87 GN with stock engine, trans. and rear end (open, yuck). The only modifications I made on this car were 160 thermostat, cold induction system from BuickGN.com, and a 9" cone K&N filter. It runs very well and it gets about 16 psi boost as indicated on the factory LED boost gauge. My friend has a 1999 GTP (supercharged). We were cruising along down the highway, and we punched the gas together to see who has a faster car. Guess what? GTP was starting to pull away slowly in ahead of me! Is there something wrong with my GN? The factory GN should get about 14.5 ET while GTP gets about 15 ET in quarter mile? Is the open rear end the reason why? Is 90k a tired engine? I am planning to get an adjustable fuel regulator and a posi unit in a little while. Would I expect a difference from these modifications? How about computer chip? Any recommendations? I have seen plenty of GN's with over 100k miles and still get about 12 seconds in quarter mile! I would like at least mid 13 in my car and be easy on my wallet. Please advise?? Thank you very much.

Jim
87 GN w/ astroroof

 

[bar87]

you need the turbobuick owner's starter kit

you could be running out of fuel....the stock fuel pump sucks,ask anybody anyway, repeat after me: fuel pump,scantool, "spring cleaning" oh & visit gnttype.org too, lots to learn there

 

[equalizer442]

whooooa now, do the basic fuel system upgrades before you start modding it. if your afraid that your cars tired go get the heads a 3 angle valve job with new springs and it will come to life.

 

[ES1]

boost guage
scantool
Adjustable regulator
adjustable wastegate
do spring cleaning on www.gnttype.org
gut the cat or get a better flowing cat
get an aftermarket chip
Tune-Tune-Tune
You might get an air-bag for the passenger side to compenstate for the peg-leg
Then when you get more $$$ buy an alky system.
I

 

[darkfa8]

there are some GTPs capable of running a lot fast with some modifications that are available through SLP and some other GTP specific aftermarket manufacturers.

Eric Schertz at Dynotech has been working on a soon-to-be high 11-second GTP

 

[salvageV6]

Race him from a stop.

Roll on races are for weenies.

Time to start modding.

 

[V8 KILR]

first things first

I was in the same situation once. When I first got my T-Type back in '91 (it was dead stock), it came off the line hard but kinda mellowed out after that. I was getting beat by Mustangs, IROCS, and my friend's stock '88 Formula 350 could walk by me once we were over 50 mph or so.

I decided to go through the car and make sure everything was working as it should. A tune up was in order. I had no boost gauge at the time, but the boost seemed to be falling off the faster I went. So I ordered a wastegate solenoid ($13) before I did any mods and installed it when I tuned up the car.

I am not exaggerating when I say this, but the car felt like it had two turbos underhood after that. There wasn't a Mustang, IROC, Corvette, or anything around that was even close. My friends Formula 350 would get buried at any speed we took off from and the best part was that now, the faster I went, the smaller he would become in my mirrors.

The moral is this: make sure your car is in a good state of tune and that all your current equipment is working the way it should. Then do as many mods as you can afford. This board is an invaluable source of excellent information. Use it and you will never worry about a GTP again.

 

[turbofrank]

If u wanna go fast u gotta spend da $$$$$$$$$$$$

 

[UNGN]

A stock GTP can run 96-98 mph in the 1/4, about the same as a Buick.

You have the air intake system covererd, now you need to work on the exhaust. Port the elbow, gut the cat and run true duals with free flowing mufflers like ultraflows. With no other changes, you will put a few car lengths on the GTP.

don't worry too much about 90K miles. Mine had about that when I bought it and the motor ran strong into the mid 11's with zero failures.

 

[JimBlackGN]

Hi,

Thank you very much for the responses. I found this very useful resource! However, I am new to turbocharger thing...I have owned my 87 GN for a couple of years, but haven't had a chance to roll up my sleeves and do some serious modifications. I have three kids, and mortgage, so I modify my GN little by little whenever the time permits.

I would like to clarify few things as mentioned above - air bag in the passenger side spring coil? Is it reconsidered as an alternate due to an open rear end? Is a posi unit absolutely necessary to have it? I know it costs somewhere between $650 to $1,000.

Wastegate solenoid - I am sorry as I may look an idiot, but where is it located? Isn't it same part as everybody has been saying "adjustable wastegate"?

Have my air intake system covered? Please clarify on this? You mean my cold air induction is not functioning properly?

Finally, I forgot to mention in the previous post that I did install the test pipe and Kirban's rear cross braces behind the back seat for stiffening up the suspensions including front frame braces underneath the engine compartment.

You guys are awesome people! Thank you!

Jim

 

[hodgeofflo]

I highly suggest getting an Eaton posi unit, after you are sure the car is running correctly stock. It is not as expensive as you think. After calling a dozen places in the phone book, I found a place that would install for $525 plus tax. I had an open diff before, and this change altered the car's personality completely. I have almost no mods on the car, and it would still spin that right rear tire to 40 mph. It was also dangerous in the surves.
BFG G-Force tires made a huge difference too.

 

[tminer]

The wastegate solenoid is an ecm controlled valve that bleeds off boost in the wastegate circuit so that the wastegate doesn't open at it's "natural" boost level. So one can have 16 psi in the manifold but only 12 psi trying to push open the wastegate. It is mounted on the passenger valve cover and thru it the ecm controls boost.

The rod on the actuator can be made adjustable (aka adjustable wastegate) so that by changing the length the amount of spring tension against the boost pressure in the actuator can be adjusted and thus change the amount of boost required to open the wastegate without having to change the eprom (chip). So if normally the wastegate opens at 12 psi in the wastegate circuit (16 psi manifold), by tightening the rod it might take 14 psi to open the wastegate which could represent 18 psi in the manifold.

Like real men everywhere, I think that the folks on here like Eaton posi. Normally about $450 at Jegs, etc, but Mark Williams had them on sale for like $320. Search on Eaton and get more info.

HTH,
Tom

 

[daturbosix]

i took my pretty much stock gn to the track last weekend, and it turned 13.6 @ 98mph with a 1.9 60' time....i feel thats damn good for a car with only a test tipe and slicks! but now i have to get a bigger, better fuel pump and im putting on a cold air, adjustable fuel reg., and my adjustable wasgate thingy. i hope to bring it down to at least 13.3, but i dunno....we'll have to wait and see.

about your car......i would recomend getting a posi unit defenatly. and a bigger fuel pump for now. then when you get more cash, buy the little things like the fuel regulator and boost control and exhaust system. my car was totaly stock except for the test pipe and slicks, and i ran a 13.6, so i think you would be happy if you can get that out of your car!

good luck, and have fun racing

p.s. show those fords who really owns the streets!

 

[Weazel]

Hey n00b, welcome aboard !
First off, don't sweat losing from a roll to a GTP. These cars aren't as good from a roll as from a stop. Your open rear wouldn't hurt you much from a roll, but if you were too fast to downshift to 2nd and started at lower rpms in 3rd, you could've given him just enough edge to start faster and keep pulling. GTPs are no slugs!
Before you start looking at valve jobs and posi rears, definitely confirm that the stock fuel pump has been replaced and hotwired! I've seen them on here for well under $100. It's a must as the stock pump was un-good.
Don't even sweat the adj. wastegate right now. If you're SURE you're getting 16 psi, you probably have an adjustable on there as stock boost was like 14psi. Don't feel bad, I owned my car for a year plus before I learned how to adjust the boost. (Now it takes like 30 seconds if I take my time).
Scantools are worth their weight in gold and then some. If you can find a garage-sale laptop, I would suggest a scantool before any mods.
Good luck and enjoy your GN!! People here have cut sub 2-sec 60' times with me on crap street tires and without posi, so don't sweat that yet. Have fun!

 

[UNGN]

Originally posted by JimBlackGN
I would like to clarify few things as mentioned above - air bag in the passenger side spring coil? Is it reconsidered as an alternate due to an open rear end? Is a posi unit absolutely necessary to have it? I know it costs somewhere between $650 to $1,000.

An airbag will help, even with a positraction. It is used to equalize the weight on the back tires during launch. When the car is accellerating, the rotation of the pinion gear in relation to the ring gear cause weight to be removed from the passenger side tire and transfered to the driver's side. The airbag preloads the passenger side, so that under accelleration, the weights are equallized.

Eatons are around $300 - $350 mail order and figure another $150-$250 for installation at most highperformance or Off road performance shops

Wastegate solenoid - I am sorry as I may look an idiot, but where is it located? Isn't it same part as everybody has been saying "adjustable wastegate"?

The wastegate ACTUATOR is the part with the rod. The Wastegate solenoid is located on the passenger side valve cover with 2 hose barbs. One barb goes to the wastegate hose, the other should be open to the atmosphere.

Have my air intake system covered? Please clarify on this? You mean my cold air induction is not functioning properly?

That air iduction system should be good into the 10's. Now you need to work on your exhaust system to free up even more HP.

 

[vettekilr]

As for your friend with the GTP,get a fuel pump,chip,valve springs,and go race him again,you'll get the last laugh!!!

 

[TRYMY231S]

Originally posted by salvageV6
Race him from a stop.

He would've really got his ass handed to him then.

 

[JimBlackGN]

All right!!

To be honest, I am getting a little overwhelmed with all of advices. I do believe that all of these advices are awesome, but I am not sure where to start first... Let me brief with you guys what I have in my GN:

160 thermostat
Cold Air Induction with 9" K&N Filter (from BuickGN.com)
Test pipe
K&N filter in front of the passenger side valve cover
K&N filter breather on the driver side valve cover

Ok. What is the next thing should I do?
Adjustable wastegate?
Adjustable fuel regulator with new high volume fuel pump but I may not need it because I only look for low to mid 13's. Stock may be sufficient unless you got me wrong?
Posi unit can wait as it may not affect the performance that much.

The reason why I said "16 psi boost". Maybe I misunderstood you guys... when I punched the gas, I saw the green LED going past the 15 psi mark on the factory LED gauge and saw a red LED lit. I thought I got it over the limit?

Jim

 

[BLACK6PACK]

Change the fuel pump, the stock one isn't good.

The factory boost guage and rpm guage are worthless.

Get a fuel pump and hotwire kit from one of the vendors that advertise on this site (ramchargers, racetronix etc)

Do the spring cleaning on www.gnttype.org

other small things to do:
chip
exhaust (hooker is only $300 shipped from summit/jegs)
fuel pressure regulator
boost guage

and most importantly a scan tool - best for beginner is the scanmaster from ramchargers.

 

[TT/Ameasap]

If you want more cheap mods type in "mods under $75" in the search section (lower right) and there is a bunch of cheap mods to get you started today.

To accomplish your goals, you will have to spend a little money first.

Fuel pump
scantool
boost guage

You can buy just about everything off of this board in our "FOR SALE" section.HTH