Max Boost on 93 Octane?

[Ttype6]

Make sure you have the right torque spec on the sensor. If you over tighten it may not work properly

When you over tighten,it becomes more sensitive.

 

[bison]

About 17-18psi on a calibrated MAP sensor and
timing retarded considerably more than would be used with higher octane. Some might see 19psi and some might see 16psi. A good map sensor doesn't leave any question as to what's actually happening. Gauges are all over the place

 

[turbo nasty]

Im with bison around 17 psi and decent timing is all with 93. Of course thats give or take on many variables to each engine give or take a few psi.

 

[Ttype6]

Im with bison around 17 psi and decent timing is all with 93. Of course thats give or take on many variables to each engine give or take a few psi.

X3

 

[turbo nasty]

Further add with a stock engine with air, exh ...norm bolt on and a stock IC and a dutt neck in the summer and humid air at 17 psi I would commonly get a lil knock in the middle of third when running. Many people will do a 1-2 hit and think its fine......its best to tune in third since you a different load on the motor from 1 to 1 gear vs. first and second.

 

[TurboDave]

About 17-18psi on a calibrated MAP sensor and
timing retarded considerably more than would be used with higher octane. Some might see 19psi and some might see 16psi. A good map sensor doesn't leave any question as to what's actually happening. Gauges are all over the place

True enough. Which is why I run both, an aircraft quality, and calibrated gauge, and a recently calibrated 3 bar map.

I'm convinced the stars and planets are all aligned for my setup.

 

[bison]

True enough. Which is why I run both, an aircraft quality, and calibrated gauge, and a recently calibrated 3 bar map.

I'm convinced the stars and planets are all aligned for my setup.

Can't argue with those numbers one bit. Good work.

 

[Undercover87T]

I'm currently running 19-20psi on just 93oct with no knock. TT chip (16/18 timing IIRC), SLIC, RJC PP, single 340 pump, 60lb inj. During the initial dyno tuning with the stock internal gate, boost wouldn't drop below 22psi but even then only showed 0.5 degree of KR with 11.5 A/F at WOT. Changed to an external gate with manual boost control to turn it down a notch until I decide to add alky.

 

[Mike T]

Nothing but 93 here in 4th . Brand new knock sensor, brand new three bar, brand new boost gauge backs up PowerLogger, 18 degrees of timing. Had a little bump of retard around 18 psi but it settled in and shifted to 4th with no knock @ 21 psi.

 

[broke]

True enough. Which is why I run both, an aircraft quality, and calibrated gauge, and a recently calibrated 3 bar map.

I'm convinced the stars and planets are all aligned for my setup.

View attachment 189620

What do you have for heads if you don't mind me asking? That's impressive! I am not sure I would attempt to go there without the methanol safety net.

 

[deezdad]

True enough. Which is why I run both, an aircraft quality, and calibrated gauge, and a recently calibrated 3 bar map.

I'm convinced the stars and planets are all aligned for my setup.

View attachment 189620

Dave if you don't mind what injectors are you running and what is the duty cycle when running that kind of boost?

 

[hawkfan]

I'm waiting for my 12v laptop adapter to arrive. I'll do some logging off of my 3 bar map when it gets here. I think the knock gauge/sensor are working fine since the gauge does indicate some activity on startup before going back to standby. I am getting a little turbo flutter at part throttle so that's another issue I'll have to sort out. Overall, the car has been well behaved on the road with no real hiccups since I got it back together.

 

[Mike T]

This is a great subject as I have a lot of questions myself about how far 93 can be pushed. My gas has came from the same 7-11 since I built the motor. The waste gate is looped on mine & the rod was a full 2 turns tighter prior to installation of the Powerlogger (before the 21 psi log). Maybe 10 wot runs were made with no audible knock, its hard to say what the boost was ??

 

[mgmshar]

I'll bite,

I can run about 17 to 18 PSI with my current RJC-style mechanical boost control in all gears. I also run the same timing in all gears. I take a different approach in that I run leaner than most in 1st and 2nd gear and still relatively lean in 3rd. Adding some fuel in 3rd gear allows me to run the same boost in all gears (kind of have to since I'm running mechanical boost control). I found it was better to add fuel in 3rd gear than retard timing with a fixed boost level.

Honestly, once I get my MAFTPRO installed and let it start controlling boost, I'll probably try to get boost levels, A/F ratios, and timing closer to what Dave is running. Some testing I did in the past suggests that increasing boost gives more performance benefit than advancing timing or running leaner.

 

[Mike T]

Just a thought, but I would think that the ethonal added to todays fuel could have a small but similar affect as alcohol. In twenty years of owning my car the boost levels have never came close to what it's running now.

 

[deezdad]

So why do people always complain about "today's crappy swill 93" ?

 

[Mike T]

My statement was not based on fact but more of a question about the possible cooling affect. Fact; the stuff has sure messed up my lawn mower & weedeater.

 

[deezdad]

No I hear ya trying to learn myself I have no idea.....maybe it's the chip technologie etc, btw sea foam works good to keep today's fuel from gumming things up just read the label it's good stuff

 

[Mike T]

I will get the sea foam. The other problem is that the new gas breaks down fuel lines. Sorry my mower comments were getting off topic.

 

[TurboDave]

What do you have for heads if you don't mind me asking? That's impressive! I am not sure I would attempt to go there without the methanol safety net.

My motor is bone stock, except for external add-on's. Turbo, inj, FMIC.