just got back (1/8 mile track) stock '87 GN


Mechanical Engineer
May 2, 2002
Well guys.... I just got home from my first trip to the local 1/8 mile track with my stock '87 GN. The only thing not stock was a K&N air filter fastened to the end of the stock MAF meter. I do have a Walbro 307 pump I installed when I got it. My car has 140k miles.... stock valve springs.... stock everything including stock catalytic converter. I did have some 26x10.5 ET Streets I mounted out back. Minimal burnout.... launched about 5 psi.... let me know what you think. Boost is stock too..... 12#??? I'm not sure what the stock boost level is....

2.06 60'
9.20 @ 73 in the eighth
O2's ran around 820 mv @ the top of 1st ... and about 775 mv @ the top of second.... no knock.....93 pump gas...

I was hoping for a better 60' .... and a 9 flat or maybe a high 8..... but no dice..... After reading some posts on here tonight.... I should have tried to leave on more boost.... like 10# or something......

I got a ton of mods to do starting this week....didn't want to put anything on until I finally could get to the track to get a baseline.

How do my numbers compare?
The 2.0 60ft would be good for street tires, but pretty lousy for ET streets.

A 5 psi at the line is fine. I stage at about 5 psi then floor it as the tree comes down with the brake still pressed. By the time you launch your boost should be close to 10 psi. Don't try to hold a static 10 psi.

73 mph indicates a lack of HP (probably around 200 - 220 RWHP).

If you had no knock at all, your boost and timing were probably too low.

There is lots of HP lost in the stock exhaust/cat (and making sure there are no preturbo exhaust leaks). Even more lost through a street chip/pump gas/low boost.

9.2 is right on for a stock GN, but that should be through the stock airbox with street tires... so you are close, but it's a little slower than it should be. I would have guessed you'd have run an 8.80@75-76 given your mods.

A chip with more timing, more boost, more octane, a test pipe with a dump you should be running mid-low 8's@80 mph.
Here is my first track experience with my bone stock 1987 grand national on real street tires and wheels. My car does have reliability mods like 36 lb inj, air filter, bov, fuel pump, and a 93 octane street chip. I was also running my car with 15 psi. My first run I left at idle, and had a 2.5 60 ft my 1/8 mile time was a 9.7@ 76.26 my 1/4 mile was 14.83@96. My second run I let my dad drive it he left slightly above idle and had a 2.296 60 ft his 1/8 time was 9.459@75.19 and his 1/4 was 14.663@94.54. The reason his mph was lower was because due to some track issues he had to run the car hot.
Went back to the track last night.....

Only performance enhancing mods I have installed are:

3" SS THDP w/test pipe
Vigilante "0-Pump" 5 disk lock-up converter
Adjustable FP Regulator
K&N Cone on the end of the MAF meter

New best: 8.46 @ 79.04 mph with a 1.84 60' time.....

Oh... I did also replace the valve springs with Comp 980's.

I am pleased to pick up .7 in the eighth and almost 7 mph.... and about .2 in the 60' with only those mods.....

Whatcha think?
Much better. Did your tires spin off the line? If not, then leave with more boost and drop another .2 off your 60'.
On the best pass.... tires did not spin..... I will try to leave harder next time. I was planning on it this time.... but I always ended up getting someone else running up and lineing up beside me..... seems everyone wants some of these black cars....... like they have a reputation or something..... :biggrin:

I'll see if I can hold up some of that reputation soon. :eek:

If I could have just made a pass by myself.....I could have concentrated more on leaving like I wanted to.... and not worried about the guy in the other lane...... I'm such a Rookie!
On a test 'n' tune night, I am the king of of the 1+ second reaction times. I won't leave until I am ready to. If I am racing, however, it's a different story.
XLR8 said:
On a test 'n' tune night, I am the king of of the 1+ second reaction times. I won't leave until I am ready to. If I am racing, however, it's a different story.

Funny you say that.... I had a 1.14 reaction time or something like that on the first run.... lol
Headed back to the track tonight :biggrin:

Wish me luck..... interested to see what the mods I did this week will net.......

Also we have a low tonight of 38 deg :biggrin: About 9 PM .... air ought to be at least mid to upper 40's.....
Well.... it did better. I wish I had bought the Translator+. I could have backed the timing down some and come up with more boost. Previous best (last Fri) was an 8.46 @ 79 with a 1.84 60'.

Tonight she went 8.32 @ almost 80 mph. It had a slight amount of knock around each of the shifts. I bumped the WOT fuel up to 4% rich. FP was set at 46 psi static (line off). O2's were no less than 806mV on the last pass. I am just about out of fuel from the stock injectors....I was able to launch at 9-10 # on a real boost gauge. I also found out it only boosts to 12 psi or so.... except near the end of each gear it spikes up to maybe 14 or so. Time to port the wastegate hole......I probably could have run 14-15 psi.... if I could have killed some timing..... damn stock chip......

Probably will put on the TE 61 and 60# high Z's this week and the extender extreme alky chip.... Don't know when I will get back to the track. I hope to pull the intercooler off and port the neck and clean out the inside (142k miles of whatever... inside I'm sure)

How much could I pick up with the new turbo/injectos/chip before I get the alky kit......??

Probably need to do something to the suspension soon..... really want to get my 60' times down..... 1.81 on the stock turbo on 12 # boost..... and the suspension is bone stock. I will likely box the uppers and lowers and install my HR Parts and stuff control arm bushings... maybe airbags.... or start on my anti-roll bar project.....
pontiac69fb said:
Don't you have an adjustatable wastegate actuator?

Yes I do.... don't think the 12 psi... is getting the knock.... I think the boost is creeping up...near the top of each gear.... causing the boost to be higher until the shift..... I had adjusted the wastegate (before going to the track) to back the boost down to try and compensate.... but it really didn't help that much.... I probably could have run 13-14 psi.... and still had about the same creep.... but don't know.

I will probably pull the stock turbo today... and install the TE61, the 60# injectors... and the extender extreme chip. I will see how that does next time to the track.
I was reading the thread with Lorenz and the Canadian guy with the limited he bought from him.

I did not dare post in that thread
But was wondering where that car ended up?


Request permission to post in that thread