What's the maximum boost you're running with stock head gaskets?

8734 Views 16 Replies 9 Participants Last post by Orlando_87GN, Dec 3, 2001

JOKER

Discussion Starter · Nov 28, 2001

Using the recipe in my signature, I get 20 lbs of boost and zero knock. In addition, I have an SMC alky kit sitting in the box. In a nutshell, I'm wondering:

1. How far I can turn up the boost and...

2. If putting on the alky kit is going to improve anything.

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87 GN (50K miles)
-TE-44
-Dutt. necked IC
-MSD 50's
-THDP
-ATR 2.5" Exhaust
-boost/knock gauges
-Tlink
-Hotwired RA XPFP
-BGC AFPR
-Lubrant 93 chip
-Translator Plus
-LT1 MAF
-ATR Bad Boy cold air kit
-Vac brakes
-Tie down strap

[This message has been edited by *JOKER* (edited November 27, 2001).]

1 - 17 of 17 Posts

d0n_3d

· #2 · Nov 28, 2001

hmmmmmmm i would like to know that answer myself...i am afraid of blowing gaskets at only 17 lbs of boost with my fuel system upgrades soon! should i even worry? 75K mile car

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http://www.angelfire.com/in4/d0n_3d/

1987 Buick Grand National - 75,000 miles, Stock engine: Poston chromed MAF pipe, homemade cold air induction system w/ 9" K&N air filter behind headlights, Poston 3" Downpipe with high-flow CAT and test pipe, 2.5" Hooker cat-back exhaust system, adjustable wastegate actuator set at 14 lbs of boost on 93 octane, K&N breather by-pass kit, stock chip, throttle body coolant lines blocked, 160 degree thermostat, CR43TS spark plugs, BFG P255/60/R15 all-weather rear tires...winter upgrades coming soon: 009 42.5 lb/hr fuel injectors, Walbro 340 fuel pump + hotwire kit, Accufab adj. fuel regulator, Scanmaster 2 first track times next spring=(

1995 Mercury Cougar XR7 - 87,000 miles, Stock 4.6L V8 Engine: dual exhaust out the rear, modified air-box with cold air induction, modified chip, adjustable fuel pressure regulator, P245/70/R16 all-weather rear tires

"Have U Been Beat...By A Grand National Lately?" <--many have been

Note to all Ford/Chevy/Import owners: BUICK OWNZ J00

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Steve Wood

· #3 · Nov 28, 2001

Stock head gaskets work very well to much higher boosts than those....all head gaskets work better with no detonation.

You should be able to run into the upper 20s with stock gaskets IF there is no detonation.

fast86

· #4 · Nov 28, 2001

2

If putting on the alky kit is going to improve anything.

Hell! I want to know how your able to run 20lb's boost without it!

Only thing you have I dont is modded IC & Trans +.

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Keith Davis**86GN,Astroroof,DigDash'TTA crank,Ported polished heads & matched intake'TRW .30 forged pistons & PT51 Turbo,Manly SS valves,CC 206-206 cam'Postons headers,Orange stripe conv.THDP,2 1/2 exhaust'Hooker comp. mufflers'SMC alky,Boost command,Scanmaster2,MSD50 inj,SS MAF & translator'Nitto DR's 275/50/15,All the braces,All gauges VDO.
12.8 @ 102 is with stock setup no times for new setup yet.

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Three Tirefryers

· #5 · Nov 28, 2001

I've unintentionally run as high as 33 psi and the headgaskets held. My "usual" boost level at the track is 27-28 on a 28-degree timing chip with no knock on VP C-16. The motor is still original with 154,700 miles (and a lot of passes) and has never been apart.

Hope this helps---

TT
'87 GN (11.19 @ 119.5, never trailered)

Orlando_87GN

· #6 · Nov 28, 2001

2

I ran 27psi with the stock turbo one night at a track rental. When I used 30* of timing and that much boost, the heads lifted but the gaskets didn't blow.

Then a few weeks later, I was messing around on the street and accidently ran the car too lean. When I hit the lockup switch I heard a big boom. Blew number 3 and number 6. That was only 20psi and 18* timing. Go figure.

Stock gaskets are pretty tough.

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Stock Block, Stock Cam, PTE-52, Champion Heads, V4, MSD50's, TH DP, JayJackson 62mm TB, 16position MaxEffort Chip. 3680# with Driver
12.0 @ 116.5mph w/20psi using 17.9* timing

mailto:[email protected][email protected]</A>

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d0n_3d

· #7 · Nov 28, 2001

3

woohoo...so what I should look into is never lean the car and try to get 0 knock with whatever boost i decide to go up to...good rules to follow i guess

man these cars sure are durable aren't they? too bad all the other parts couldn't be like the head gaskets and hardly fail!!!

------------------
http://www.angelfire.com/in4/d0n_3d/

1987 Buick Grand National - 75,000 miles, Stock engine: Poston chromed MAF pipe, homemade cold air induction system w/ 9" K&N air filter behind headlights, Poston 3" Downpipe with high-flow CAT and test pipe, 2.5" Hooker cat-back exhaust system, adjustable wastegate actuator set at 14 lbs of boost on 93 octane, K&N breather by-pass kit, stock chip, throttle body coolant lines blocked, 160 degree thermostat, CR43TS spark plugs, BFG P255/60/R15 all-weather rear tires...winter upgrades coming soon: 009 42.5 lb/hr fuel injectors, Walbro 340 fuel pump + hotwire kit, Accufab adj. fuel regulator, some kind of scan tool; first track times next spring=(

1995 Mercury Cougar XR7 - 87,000 miles, Stock 4.6L V8 Engine: dual exhaust out the rear, modified air-box with cold air induction, modified chip, adjustable fuel pressure regulator, P245/70/R16 all-weather rear tires

"Have U Been Beat...By A Grand National Lately?" <--many have been

Note to all Ford/Chevy/Import owners: BUICK OWNZ J00

[This message has been edited by d0n_3d (edited November 28, 2001).]

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Steve Wood

· #8 · Nov 28, 2001

The only parts that are susceptible to failure after many miles are the sensors.

The engine is relatively bulletproof-again, detonation must be avoided. At 17# of boost, it may only nick your headgaskets gradually but at 27# it happens quickly. It is also hard on the bearings as it hammers the rods back against the crank.

With regard to gasket types, I am not sure that more people not had better luck with the stock type than some of the aftermarket o-ringed type but that is probably due to improper installation.

I use the factory shim on my cars...just one for more compression and believe they work well.

Remember, if something is not right, it is often better to blow a gasket than the drive over the crank....

raregn

· #9 · Dec 1, 2001

I was sitting in the passenger seat of my buddies 87 T and I watched a 30 psi boost gauge get pinned and the engine held together with no ill effects. Although this is not something I recomend. That was also on pump gas, the waste gate hose fell off the turbo.
I was also at the track this year and was standing right beside the stage line to watch another 86 T-Type launch to see if he was getting excessive wheel spin, and I was treated to a headgasket going off 10 feet away from me. That was freakin' loud. That was imideatly followig a 12.4 run.

JOKER

Discussion Starter · #10 · Dec 1, 2001

Originally posted by fast86:

Hell! I want to know how your able to run 20lb's boost without it!

Click to expand...

Trust me.....it's luck!

Thanks for the replies, guys. From the above statements, I'm guessing that 25 to 27 lbs of knockless boost won't create an overpressure situation. I was told, by a friend, to not take it over 20 lbs.

Geez.....that's 50 to 70 more horses!

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Steve Wood

· #11 · Dec 1, 2001

I was running about 23# at 24 degs today on 93 plus the smc....again, I run a single shim gasket for the additional compression but you should have no problems in the 25# range...further you push it, the more cylinder pressure you build, and the more wear that you cause...

Just sneak up on it and don't increase the boost in 5# increments! *g*

toady

· #12 · Dec 2, 2001

Locally, Ryan Guy runs over 30psi with stock or stock-type gaskets. Well, before Vegas, anyway... Dan Powell runs up to 33psi with an untouched longblock.

JOKER

Discussion Starter · #13 · Dec 2, 2001

Well, I found the limit. Last night, I got her up to 22 lbs of knockless boost on pump gas. 23 lbs gave me 1.5* to 2.0* of knock, so I returned to 22 lbs. Again, I'm getting an occasional 1* to 1.5* of knock, but I'm convinced that it's false knock from a rattling DP.

Steve Wood

· #14 · Dec 2, 2001

just remember to always leave yourself a little margin in case you get a tank of bad gas or conditions change....

JOKER

Discussion Starter · #15 · Dec 2, 2001

I was thinking the same thing. Well...not about the specific conditions (i.e. bad gas), but the margin thing. I'm dropping her down to 21 lbs today. Thanks again.

TurboDave

· #16 · Dec 3, 2001

Originally posted by Orlando_87GN:
I ran 27psi with the stock turbo one night at a track rental. When I used 30* of timing and that much boost, the heads lifted but the gaskets didn't blow.

Stock gaskets are pretty tough.

I'm still trying to figure out how you determined that the heads "lifted"???? Some magical "head lift" guage we don't know about?

------------------
TurboDave & Kathy Huinker, mailto:[email protected][email protected]</A>
TurboD Racing,Turbo Buick Web Ring
San Diego CA http://home.san.rr.com/buickv6/
86 GN[email protected](MM/MAF Xlator/Extender,MM BstC Boost Command,THDP,PTE44,CAS V2FM,MSD50's,9.5"vigilante 3500)
87 GN [email protected](Stock)
84 Z28 L69
01 Excursion LTD TTS"race" chip 7.3L PSD(power stroke diesel) Turbo 4X2
Pictures of my toys

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Orlando_87GN

· #17 · Dec 3, 2001

2

God awful sound like open headers when the car hit 3rd gear through the end of the pass. Did it on about 4 runs in a row and when I couldn't figure out what the noise was, I switched back to 18* timing. Car ran the same times with no noise.

That and some really loose head bolts. 1/2 on a few, 1/4 turn on most.

------------------

Stock Block, Stock Cam, PTE-52, Champion Heads, V4, MSD50's, TH DP, JayJackson 62mm TB, 16position MaxEffort Chip. 3680# with Driver
12.0 @ 116.5mph w/20psi using 17.9* timing

mailto:[email protected][email protected]</A>

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