Author Topic: TT chip and octane  (Read 14747 times)

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Offline Shimy87

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TT chip and octane
« on: June 14 2021, 08:31:41 PM »
I have a tt chip, marked 60 lb injectors , 93 octane, 15-17 boost. I think 21 degrees timing but not sure. I can only get 91 octane. When I roll into boost (12 lbs) in drive I get bad knock. I tried adding 6% wot fuel but I don't even get to wot. Will I need a new chip burned for 91???
87 GN, K&N cold air, gutted cat, TT 5.7 chip, AFPR, 340 Walbro w/ hotwire, 60 LBS injectors, 981 valve springs, 206/206 Cam, RJC Powerplate, LS1 MAF & translator, Vacuum brakes, Hellwig rear sway bar, Energy suspension poly bushings, Razors Alky, Pypes exhaust, 5931 turbo, CK9.5 converter

Offline Steve Wood

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Re: TT chip and octane
« Reply #1 on: June 14 2021, 09:32:20 PM »
Under the assumption that it is hearing real detonation and not false, set the third/fourth gear timing to 18 degs
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Offline Shimy87

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Re: TT chip and octane
« Reply #2 on: June 14 2021, 09:37:42 PM »
I can hear it as well so pretty sure its real, should I set 1/2 gear as well? I punched it from a stand still and instant knock.

Also not sure on the timing marked on the chip, will pull it and check first.......th anks!!
87 GN, K&N cold air, gutted cat, TT 5.7 chip, AFPR, 340 Walbro w/ hotwire, 60 LBS injectors, 981 valve springs, 206/206 Cam, RJC Powerplate, LS1 MAF & translator, Vacuum brakes, Hellwig rear sway bar, Energy suspension poly bushings, Razors Alky, Pypes exhaust, 5931 turbo, CK9.5 converter

Offline Steve Wood

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Re: TT chip and octane
« Reply #3 on: June 14 2021, 09:51:46 PM »
It will not hurt to reduce 1/2 by three degrees from whatever is marked on the chip as well.  18 degs used to be pretty much standard and they sometimes will be faster with 18 degs than with 21.
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Offline Steve Wood

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Re: TT chip and octane
« Reply #4 on: June 14 2021, 09:53:05 PM »
make sure your fuel pressure is rising with boost
Steve Wood

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Offline Shimy87

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Re: TT chip and octane
« Reply #5 on: June 14 2021, 10:11:44 PM »
Fuel pressure is rising

Chip says 20 degrees - 18 degrees

Also 16-18 lbs boost, seem like alot of boost for pump gas??
87 GN, K&N cold air, gutted cat, TT 5.7 chip, AFPR, 340 Walbro w/ hotwire, 60 LBS injectors, 981 valve springs, 206/206 Cam, RJC Powerplate, LS1 MAF & translator, Vacuum brakes, Hellwig rear sway bar, Energy suspension poly bushings, Razors Alky, Pypes exhaust, 5931 turbo, CK9.5 converter

Offline Steve Wood

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Re: TT chip and octane
« Reply #6 on: June 14 2021, 10:17:13 PM »
I think 15 is pretty good on 91 octane.  try 18-17.  Bob Bailey used to set his to 17 in third gear in the old days.
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Offline Shimy87

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Re: TT chip and octane
« Reply #7 on: June 14 2021, 10:27:12 PM »
Thanks Steve!
87 GN, K&N cold air, gutted cat, TT 5.7 chip, AFPR, 340 Walbro w/ hotwire, 60 LBS injectors, 981 valve springs, 206/206 Cam, RJC Powerplate, LS1 MAF & translator, Vacuum brakes, Hellwig rear sway bar, Energy suspension poly bushings, Razors Alky, Pypes exhaust, 5931 turbo, CK9.5 converter

Offline Steve Wood

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Re: TT chip and octane
« Reply #8 on: June 14 2021, 11:03:13 PM »
thinking about it, the alky is out on my GN and I think 14 is about it altho it has more compression than factory...it also has a 210 deg cam which should help...but 14 to maybe 15 is all it will do on 91
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Offline Shimy87

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Re: TT chip and octane
« Reply #9 on: June 15 2021, 10:20:19 AM »
I was thinking also,
car has a TA 49 turbo and a 3 in DP. Im guessing the chip was for a stock set up so I probably have to add alot of fuel also?
87 GN, K&N cold air, gutted cat, TT 5.7 chip, AFPR, 340 Walbro w/ hotwire, 60 LBS injectors, 981 valve springs, 206/206 Cam, RJC Powerplate, LS1 MAF & translator, Vacuum brakes, Hellwig rear sway bar, Energy suspension poly bushings, Razors Alky, Pypes exhaust, 5931 turbo, CK9.5 converter

Offline Steve Wood

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Re: TT chip and octane
« Reply #10 on: June 15 2021, 11:20:34 AM »
Could be.  Look at your o2's at wot toward the higher end of the rpm range if possible.  If they are around 780, the fuel is good.

i'm not sure the Octane rating of today is comparable to the octane of yesterday so it may be difficult to make comparisons as to what it should do now.  I recall that when 91 came out in Ca years ago.  Everyone was turning the boost down or buying alky kits.
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Offline Shimy87

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Re: TT chip and octane
« Reply #11 on: June 16 2021, 01:01:38 PM »
Well, no suprise, this old girl is determined to be dificult. lowered timing in first/second to 17 and also in 3/4. added 10% WOT all gears fuel, turned up FP to 45 hose off for good measure. Still knocks, cant even get to WOT long enough to have SM retain info. SM knock got up to 4.6 when I lifted. I'm thinking I should just get a chip burned for this cars specific's? I tried to roll into boost in drive from about 40 mph also and cant even get to WOT before I need to lift because of knock.

another weird thing, after one pull, slowing down from 90 mph'ish, foot off gas, O2's read 0 for the longest time, then blipped the gas and they came back???
87 GN, K&N cold air, gutted cat, TT 5.7 chip, AFPR, 340 Walbro w/ hotwire, 60 LBS injectors, 981 valve springs, 206/206 Cam, RJC Powerplate, LS1 MAF & translator, Vacuum brakes, Hellwig rear sway bar, Energy suspension poly bushings, Razors Alky, Pypes exhaust, 5931 turbo, CK9.5 converter

Offline nocooler

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Re: TT chip and octane
« Reply #12 on: June 16 2021, 01:12:48 PM »
Are you sure it's real knock? Bad tank of gas?
IhaveaV8

Offline Shimy87

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Re: TT chip and octane
« Reply #13 on: June 16 2021, 02:11:07 PM »
gas is new, its real, I could actually hear it
87 GN, K&N cold air, gutted cat, TT 5.7 chip, AFPR, 340 Walbro w/ hotwire, 60 LBS injectors, 981 valve springs, 206/206 Cam, RJC Powerplate, LS1 MAF & translator, Vacuum brakes, Hellwig rear sway bar, Energy suspension poly bushings, Razors Alky, Pypes exhaust, 5931 turbo, CK9.5 converter

Offline nocooler

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Re: TT chip and octane
« Reply #14 on: June 16 2021, 03:20:05 PM »
I'd reach out to Eric about the chip.
Can you add some octane? Xylene, Toluene, or something like boostane, racegas concentrate, torco, vp octane boosters to see if it goes away?
IhaveaV8

 

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