NEW to Turbo Buicks - PTE Chip Timing


New Member
Hi, I am new to the forum as well as turbo Buicks and have a few questions.

First I have a 1987 GN with 52k miles The car was my dads and he is no longer around to ask questions about the setup. From what I can gather this is the current setup.
TA-49 Turbo
Lucas 42.5# injectors
Fuel pump unknown, I know it is hotwired, I have a racetronix 255 ready to go in to replace it as the pump in it is making noise.
Caspers Electronics TPS-Tec
Aftermarket FPR, Was a custom made one back in the 90s by a good friend of his its a billet unit, its operating correctly 43pis and rising 1:1
Delco CR43TS , Kirban Grey Spark plug wires Ranging from 500Ohm-700Ohm (Brand new - 2 weeks old)
Gutted catalytic converter and high flow Cutback exhaust
PTE 93 Octane Street chip 20* timing

My big question here is at 18PSI of boost I am still seeing about 3-4 Degrees of Knock Retard so it was turned down to 14Psi to be extra safe, but I still see about 1-3 degrees of knock retard here and there. I most often see 1-2 degrees when I let off the throttle and there is no Knock retard when I am WOT. I was assuming the 20 degrees of timing on the chip is just slightly too high for todays modern 93 pump gas. So as a response to this I ordered a 5.7 TT chip and was going to set the boost to 16# for a happy 93 pump gas setup. Assuming Eric at TT would probably set the timing to 18/17. Does anything seem blatantly wrong with this mindset in logic ? I did a lot of research here and I hope I am on the right track.

The goal for this car is a low 13s 93 Pump gas car, that can be car cruised and driven without having to deal with alk or race gas. (Maybe ALK in the future but I will probably save that for my second buick)
You’re probably seeing false knock from somewhere. Downpipe hitting the frame/upper control arm, bad motor mounts, slipping trans… mine was slipping and giving me KR, I chased a knock issue for a year. Got the trans rebuilt and the KR magically went away. With 93 today you shouldn’t run anymore than 18 pounds of boost. 20° is a lot of timing in my opinion, I run 25 psi of boost and alky, with 17-18° of timing at wot. If it’s not false knock, stop driving the car. You’ll kick the headgaskets out of it or destroy the rod bearings and then… bye bye engine. The fact that you’re only seeing it when you let off the throttle says to me that it’s false.. Something might be rattling ir banging around. Or if the motor mounts are worn the motor is settling back down and setting off the knock sensor. Many things to look at and I’m sure someone with more experience will chime in.
To confirm if its false knock or not put some higher octane fuel in it. If its not readily available another option is a can of VP Octanium. Most auto parts stores carry it. Dump 1 can in and then add 10 gallons of fuel. Its not a long term solution but till tell you if the knock is real. Also watching the Scanmaster is difficult to do while driving, thats where a powerlogger shines. Much easier to spot trends.
So in the meantime I can try adding a few gallons of race gas or VP octanium and see how that plays out, should be able to raise the octane rating by a few points and clear things up, if the knock is still there then I know its a false knock, which could be from many things. I will give this a try next weekend. Next week I will also drop in the new fuel pump and the TT chip. If it clears up completely I know its not false knock and then its probably due to the timing or maybe other things ?

Can a stock downpipe hit the frame , I assumed that was a larger downpipe problem ?

I don't have a powerloger setup but eventually I would like one, for now I am stuck with just a scanmaster
100 or 104 Unleaded if available in your area would work well, or add a gallon of xylene (home depot) to about a quarter tank of gas raises the octane from 93 to 98 or so for a test.
Put the parts in you have before the tests then worry about it. No need to chase it twice it's probably false.
@salvageV6 I will install the fuel pump this Saturday so I will drain the tank and throw out that fuel, Sunday I will pickup 5.5 gal of 100 and mix it with 5.5 gallons of 93 Should make a 96.5 Octane mix (I cant get 104 sadly no one has it readily available). Then I can do some tests on 14-15 PSI and 20* of timing. It absolutely shouldn't KR on that tune up. I believe this tune used to run fine about 5 years ago on a 50/50 (100/93) mix but honestly never paid attention enough back then. I wont get the TT 5.7 93 street chip for another 2 weeks as I just ordered it. So that's simple enough to swap out once that comes in and I can do the same test on the same tank off gas.
So over the weekend I installed a racetronix 255lph pump, when I went into the tank I found a walbro 307 pump (the old 307 pump was for sure bad it sounded horrible and was stuttering really badly when pumping out fuel). After completing the fuel pump I put a 96 octane mix in and left it at abut 14 psi. Then the KR went down to 0 KR . So took it a step further and set the boost pressure to 17-18 psi FP was set years ago at 46 With Vacuum line off. The car absolutely woke up spooled up in 1/3rd of the time and has 02 readings of 800-820 0KR still. So I figured out 2 things here. I think the car is a hair rich (not a bad thing) and was setup to run more like 19-20 psi on a 93+ race gas mix which would explain why its alittle fat and would also explain the 46 psi on the FPR. Additionally I believe the car has a heavy duty wastegate actuator which is why if I turn it down below 17-18 psi it takes days too spool up since its just constantly bleeding off pressure.

So today the car is on 17-18 psi Boost, 20 degrees of timing on a 96 octane mix with 0 KR, O2 800-820(This is a hair rich I don't think its too rich but better to be rich than lean) at 46FPR Line off, Line on 42 PSI. Much happier setup and looking to change to a TT chip once that new chip comes in the mail. Also may get a standard wastegate actuator to be able to set the boost in the 16-17 psi range without adding massive lag.

I believe my past 1-3 degrees of KR on the 14 psi setup was probably due to bad fuel in the tank or the fact the fuel pump was taking a shit.