19 Pounds of Boost safe for Stock GN.

[black84]

I am currently running 19 pounds of boost in my stock 87' Gn. The only modifications on the car are a walboro 340 hot wired and VDO boost gauge. The only reason I'm asking is because I called Poston's the other day and some older guy advised me when asked, that it was ok to bump the boost up to 19 psi on 91 octane. He advised that he was running that amount of boost and it was safe. I don't have a scan tool and I don't think I hear any knock. The car is only driven maybe only twice a week. Any help is greatly appreciated.

 

[turbosam6]

No, its not cool. Every car is different, and you can't hear all knock, only severe knock. Turn it down to 13-14 and get a scan tool!

 

[turbot2112]

deffinately get a scan tool or at least a knock gauge. i used to run that much and more with my stock motor and no scantool and well, im on my second motor.

 

[jastrckl]

Once you get a scantool you'll be able to tell that you can't hear knock until about 10* of retard. That's too much!

 

[GNVYUS 1]

Wow, someone at Postons said that?
91 octane is the crap of high octane gas, you would be lucky at 14 psi stock on that crap. And 19 psi is more than most guys run on 93 with a FMIC and 20 degrees of timing.

I would cool off on doing things to your ride until to check out the board more often. Its worth spending the time on here to learn whats up so that your not spending the time on here finding out who is a reputable GN shop near you for rebuilds.

Stop calling postons

 

[black84]

Thanks for all the replys I'll turn it down to 13-14 psi. I don't know why anyone at Poston's would ever give me that type of info. Thanks again.

 

[scottyb]

Originally posted by jastrckl
Once you get a scantool you'll be able to tell that you can't hear knock until about 10* of retard. That's too much!

What he said.

17 is pushing it on 93 octane. Maybe 18 with a power plate on a GOOD day.

 

[gnx7]

Get a scan tool and dump in a few gallons of Xylene or Tuolene in with the 91 to raise the octane if you want to run that boost level. Don't forget to add in a few tablespoons of Marvel Mystery Oil. going from 14psi to 20-21psi on a stock turbo is like day and night.

Xylene 117 octane
Tuolene 114 octane
MMO- adds in some lubrication for the cylinder walls.

3 gallons of Xylene
7 gallons of 91
3 tbl spoons of MMO

make 99 octane and is perfectly safe.

-GNX7

 

[V6UnderPressure]

For the record, I had a duttweiler big neck IC, msd 50's, walbro 340 power plate w/pte plenum, & pt54 blah blah blah. and was running constant 19psi with 93 octane with occasional mild knock in 3rd. (on a cool night) I would say you would be ok with 18, but 17 to be safe. 13-14 is well below what your capable off with 93 octane. but that 91 is the crap of premium fuel as said before. There are 94 octanes out there. Unfortunately none near me. First things first, get a power plate. That can solve alot of problems and probably the best investment for the buck in my opinion.

Scott