How much is too much boost for stock config

[70Firebird/TTA]

Bought my TTA with 21,000 miles and noticed right off that my Boost Solenoid was disconnected and that I was running an adj wastegate set at 16.5 lbs max boost. Today I reconnected the hose plumbing with correct Y connector ...thus reconnecting the solenoid. I noticed that my car warms up a little smoother and now boosts in the red.

Question: How much boost over 16.5 is safe with stock config running 91 octane??? Is it going to blast my engine if it's going to 18 lbs??? I was thinking that there should be some leway and that factory tune was conserative like most production line vehicles. Am I right???

Thanks in advance.

 

[Gokou]

You need a scantool to check for knock to determine what is safe.

My car wasn't safe with the stock chip at stock boost level (16.5psi); I was seeing 6-8 degrees knock retard on our wonderful 91 octane pump gas around here. Remember, back when the car was made you could still get 94 or 93 octane at the pump here in CA. The factory chip and factory boost level is too aggressive for our 91 octane.

I'd say you are asking for serious trouble at 18lbs on 91 octane. Turn that boost down before you eat a headgasket! I'm running 16.5 psi on pump gas 91 octane with a Thrasher 92 chip (more conservative on timing than the original) and that is just on the verge of having knock. If your car is pretty much stock and running the stock chip at 18psi I don't doubt you're getting upwards of 10 degrees of knock retard, and that is REAL bad.

You really need a scantool of some sort to see how much knock you are getting and to check the mixture. Start low and work upwards. When you start getting knock, back it down a hair. How much you can run will determine what mods you have, chip you have, and fuel you run.

Does the car have any mods? If so, which? That will also help us help you. But do yourself a BIG favor and buy a scantool such as a Scanmaster before you eat a headgasket. If you have no way to watch knock retard, set it on the safe side (~15psi boost) for now, because you have no idea what's going on without a scan tool.

 

[1BADDAM]

Like Gokou said on 91 oct. your not gonna get away with much over stock if that. With the power plate, Thrasher 92 and a nice cold winter night I was getting away with 18#'s with a degree or two of knock. I just run straight 110 oct. now, cheap insurance for weekend/track car and with the gas prices so high, at $2.25 a gal., easy to justify. A scan tool and a 30# boost gauge would be a wise next purchase, take the guessing out of play.

 

[Gokou]

Gotta love our gas here in CA. I about puked when I heard last year they were changing from 92 to 91 octane. WHY?!?!? Oh well.

With my current combo and 100 octane unleaded I could get away with 20psi and 0 knock. Didn't feel the need for any more octane as I didn't want to push my luck much past 20psi.

While the car is faster on the 100 octane and 20 psi, I can almost live with the pump gas tune, because it's VERY nice to be able to fill up anywhere with 91 octane and not worry about knock. The convienience almost outweighs the performance loss... almost.

Troy

 

[70Firebird/TTA]

Gokou
Thanks for the advice. I believe that you are correct. I need to get a Scanmaster and/or a detonation gauge. I will probably need to lower my boost BELOW stock. I have noticed on WOT that the engine does buck a bit (detenation/computer retarding timing). I will probably go the route of lengthening the Wastegate arm running to the Turbo.


On my adj wastegate....I notice that there IS a nut that loosens in the middle of the wastegate arm/shaft. I loosened it at one time and couldn't figure out how to increase/decrease the length of the arm. Thought about turning the arm portion facing the Turbo side counter clock wise to lengthen...no luck..and the thing wouldn't bundge. For those that have done this...what are the recommendations? Am I missing something? Is there a recommendation to go by in terms of how much boost will be detracted if the length of the arm is shortened by 1/2 inch...1 inch...2 inches????? A general frame reference would be great so that I can avoid going "agro" on the adjustments.

Thanks

 

[70Firebird/TTA]

Nevermind. Found my answer. The cotter pin will be removed from wastegate arm that attaches to the Turbo actuator AFTER the locking nut is loosened from the shaft. Then the arm can be rotated counter clockwise to enlongate shaft for decreased boost.

Does anyone know how many turns on the arm are required to increase/decrease boost by a 1 lb psi??? I am thinking of going low and building from there until I get to around 15.5 lbs to accomodate my sucky 91 octane.

Your help is appreciated.

 

[TT/Ameasap]

70Firebird/TTA, At the end of the WG rod there is a C clip or maybe a roach clip . you must pull it out and then pull on WG rod. Turning the WG rod in to shorten it will increase boost. Turning it out making it longer would result in lowering boost....

Each full turn is about 1psi


If you have a thrasher 92 chip.... keep boost around 13-14psi till you get a scantool. Otherwise just keep your foot out of it!

I suggest to start with a Scanmaster 2 and if you want to get serious, Turbolink or Direct Scan can be added with the SM2 to see your KR while racing.HTH

 

[Razor]

Ahhh.. TTA rule one..get a scanmaster..buy it know or get it after you destroy the motor..

easy..

I run 25 lbs of boost with 93 octane and alky..zero knock

I havent touched my wastegate since June last year..when I installed it..cant go back to 16lbs..I'd hate being someones biotch on the road..or track

 

[70Firebird/TTA]

Had fun testing the car after turning boost all the way down to 10 lbs @ WOT. A couple turns clockwise (shortening) the arm...got close to 15 1/2 to 16 lbs. I am targeting 15 lbs. I really like setting the hose plumbing back to stock...the car seems to warm up and idle smoother. There used to be a slight rattle eminating from the Turbo when warming up...now the sound has quieted down 85%. I will have to continue testing tomorrow to make sure the car is as close as possible to the 15-15 1/2 pounds.

 

[mrtransam3]

knock

just wondering if you ever heard of OCTANE BOOSTER! A can of it will do wonders for that crappy 91 octane. I don't know about Cal. but it is available here in about every store you walk into!

 

[TT/Ameasap]

Re: knock

Originally posted by mrtransam3
just wondering if you ever heard of OCTANE BOOSTER! A can of it will do wonders for that crappy 91 octane. I don't know about Cal. but it is available here in about every store you walk into!

0.3 points for $5 bucks ....... I just got zylene at sherwin williams for $22.60 tax included

Julio, when are we all going to invade bradenton? 4 TTA's would make for a cool night





Bo

 

[Razor]

Bo..22.60 dam thats cheap.. I assume thats a 5 gallon can..I pay 25 from Scott Paint up here..I thought that was the cheapest..

WANNA MAKE A GALLON OF 104..

110 oz of Xylene..octane booster,10 oz of ATF..lubricant..,8 oz of mineral spirits..cleaner..

Or screw that..get your tank low..drop in a couple gallons of Xylene..couple oz of Mystery oil..Bada Bing..

I went to the SLP event at Orlando Speed World today.. ran 4 times on radials..best was a 12.02 with a 1.9 60 foot..worst was a 12.23 with a 2.25 60 foot..116-117 trap speed..then drove home

I have a huge farmers tan

Lemme know on Bradenton..I'm always game.

On the boost subject..15 lbs shouldnt hurt too much unless its detonating if it is..get ready..

Priced a TTA crank lately..easier time finding Bin Laden..

Buy a scanmaster now or latter..