high boost pump gas question

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neverlift
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high boost pump gas question

Post by neverlift »

Looking for timing advice, what do you guys do above 25psi for timing?

This is a built motor est. 9.1:1 compression 93 octane, likes timing retard around 1*:1psi, which sets the advance at 0* for 25psi. The question is would retarding the timing further into atdc reduce chance of detonation since the piston would already be moving down the cylinder?

Any help would be great.
Thanks
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Re: high boost pump gas question

Post by Kill3rwill »

I doubt you'd want to push pump gas boost that high without a Dyno. At 21 psi, the highest I ever ran on 93 I was around 12.5 degres for safety. On e85 and 26 psi now at 14 degres
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Re: high boost pump gas question

Post by Greaser »

what ecu
what camshaft
what size valve
what size turbo

My test bed tuning motor:
9:1
stock s14 cams
stock valves
ported head
50trim
Bosch knock sensor

This setup WILL knock at 10deg timing at 11psi on 93 in the summer heat. Winter time I run 15psi at 5dbtc. Timing depends on your setup and airflow capabilities. Timing tables I long ago used to program i am learning are wayyyyyy to agressive once you get out on the street and actually listen for knock. My current setup isnt about power its about knock detection, which i'm learning everyone should be implementing.

25psi and pump gas is asking for hg replacements often.
neverlift
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Re: high boost pump gas question

Post by neverlift »

gt3076
turbohaulic cams
stock valves
aem series 2
commetic

this is not on the dyno what so ever ,maybe after final street tuning for numbers or smoothing things.

I'm getting one guy saying I should run 12.5* at 21psi(looks away),and another guy saying at 21 psi I would roughly be at -15*. This motor is running on the street at 18-21psi, timing at 18psi is roughly 6* and at 21psi roughly 3-4* 93 octane pump gas highway pulls back to back to back(drift car)

I'm just looking for an answer not to be told we shouldn't do it. Owner knows the risk and as his tuner I have informed him thoroughly he is on the edge of pump gas limits, admittedly I've never ran one up this far, but the 1:1 method has proven very reliable for me.


"The question is would retarding the timing further into atdc reduce chance of detonation since the piston would already be moving down the cylinder?"
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Greaser
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Re: high boost pump gas question

Post by Greaser »

yes it will. So will making it run 10:1 afr.

series 2 is really good for knock control. Put a stock knock sensor on it and find out what the limits are.
neverlift
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Re: high boost pump gas question

Post by neverlift »

thank you!
I doubt we will go that far, as said owners been warned, pump gas is sketchy at higher power. I like to double tap knock with rich mixture and typically 1:1 timing retard, been working for years.


oem s14 knock sensor is wired up and set to 6.64 khz centered frequency??? NOT sure that is right, looking but not finding.

Was trying to get away with .75* per psi but that set the sensor off. I'd prefer not to push the limits but the owner spent his money and its his choice at the end, rather watch it last a few years drifting :D


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Greaser
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Re: high boost pump gas question

Post by Greaser »

Well that frequency is calculated to be right, but far from optimal. Using a program called "Goldwave" you can record signals from your knock then analyze the file with a spectrogram which shows you amplitude across whatever frequency range you choose. From this you can tell what frequency range is background noise(piston slap and valve lash slap) and what frequency is actual knock giving you the best s/n ratio.

On my engine using a chassis ear alligator clip mic on the engine I made it knock a couple times and there are several frequencies better than 6.64khz to use. But I wont change it until I connect the knock to laptop and record that. Since it works so well using the "calculated" frequency

if its coil on plug is knock per cylinder on?
whats your integration period?
Gain?
Output voltage from knock sensor?

Look up Motec's SKM / OKM standalone knock monitor and download the instructions how to use it and set it up. A good amount of info in the manual.
neverlift
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Re: high boost pump gas question

Post by neverlift »

not cop yet, being s14 with internal coil plug gap already down to like .018 IIRC ,getting blow out at 20psi at .028.
integrator at 300us(microsec)
gain at .421
get volts next time with car

looking into that motec and goldwave for sure.
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Re: high boost pump gas question

Post by Greaser »

**** my gain is maxed at 2. No knock max volts at redline is like .7 volts.
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Re: high boost pump gas question

Post by duncan351 »

Your motor won't built too much longer if you keep running that much boost on pump 93 octane. Its been tried and every time it ends up with a motor rebuild.
843whp @ 40psi
761/596 Tq 33psi 6766
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neverlift
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Re: high boost pump gas question

Post by neverlift »

Even though I have some investment in the motor as far as my time goes, its not my motor. I have and continue to warn of the current limit we are at, last thing I want is the motor to blow! Owner agreed to leave car around 20psi until e85.


greaser
max volts is .05 at the three to four shift(same setting didnt play with it yet).
Also ever have corruption issues with aem files? Working tune rolled onto trailer fine came off acting completely stupid and flat, loaded the tune again car dropped 3 seconds in the 1/4. odd
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Re: high boost pump gas question

Post by Greaser »

.05 is barely useable data for s/n ratio. Turn up that gain to 2. Wideband bosch sensors need that. Change that and do a pull and enjoy the increased data points. On a good tuneup knock volts will increase with rpm with no spikes. Yes it'll be 10-20hp down from a hot tuneup that is 3-6 degrees more but it'll last oem 100,000 miles. There are different amplitudes of knock and what power its making when it pings whether or not it pops. If youre like me, I don't accept any level of knock.


Yes i've had the "corrupt file" issue. Its not that its corrupt, its a coms issue when you connect disconnect imo. Also emi/rfi. Use shielded cable on all inputs, route any 10amp or higher current cables away from main harness. Just like wiring a stereo system. Amp powers on one side of the car, rca's on the other. Use only resistor plugs.(for any electronic controlled engine)


My process is to plug in usb, connect through the program prompt and disconnect from the ecu through the program before pulling the usb cable out. EMS 4 is the worst it'll "corrupt" a whole datalog file doing the disconnect/reconnect wrong.

Make sure you don't use "loop logging", From aem directly it does not work and will "corrupt" datalogs.
Make sure "auto eeee" is ON.....When turned on, the calibrations made live will automatically be stored into the EMS. Always leave this ON. If you have this turned off then any changes you make to the calibration will be lost when you turn the ignition off.

Those issues could cause some problems as we all have experienced before.
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Re: high boost pump gas question

Post by nissanfanatic »

I always stuck to 14psi on pump gas on all of my setups which was around 350whp. Stock motor w/T04E and T04R and built motor with T04R.
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Re: high boost pump gas question

Post by duncan351 »

nissanfanatic wrote:I always stuck to 14psi on pump gas on all of my setups which was around 350whp. Stock motor w/T04E and T04R and built motor with T04R.
Same here and every now and then I pushed it to 17psi for a quick hit but daily 14-15psi.
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761/596 Tq 33psi 6766
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Re: high boost pump gas question

Post by supakat »

I run 20psi daily and high boost depends on the barometric pressure since my WG map is open loop. I typically hit 28psi but have hit 34psi (9* timing) with no knock or lean outs (11.3afr). I need to put on closed loop but haven't had time to st it up correctly. I am lucky to have corn only 10 minutes away. If I was on 93 even with meth, I doubt the motor would have not lasted as long as she is now which is 4.5 years.

There is a line between making good power to run on the street vs reliability. I choose reliability any day. No matter what, someone is gonna be faster so build something that makes you happy and tickles your fancy every time you go WOT is key. And as stated above, you can have all name brand parts but if your tune is not safe, your motor regardless of how much money you spent will not be reliable.
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nissanfanatic
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Re: high boost pump gas question

Post by nissanfanatic »

supakat wrote:I run 20psi daily and high boost depends on the barometric pressure since my WG map is open loop. I typically hit 28psi but have hit 34psi (9* timing) with no knock or lean outs (11.3afr). I need to put on closed loop but haven't had time to st it up correctly. I am lucky to have corn only 10 minutes away. If I was on 93 even with meth, I doubt the motor would have not lasted as long as she is now which is 4.5 years.

There is a line between making good power to run on the street vs reliability. I choose reliability any day. No matter what, someone is gonna be faster so build something that makes you happy and tickles your fancy every time you go WOT is key. And as stated above, you can have all name brand parts but if your tune is not safe, your motor regardless of how much money you spent will not be reliable.
Same. It is pretty rare that you run across something that traps higher than 120mph on the street. And if it does, people still look at you funny if they don't absolutely destroy you... :P
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Re: high boost pump gas question

Post by supakat »

Looking back this is irrelevant without stating turbo size which is 60mm and flows around 61lbs/min. I am going to buy this soon to help increase power throughout the powerband and help with spool which I really don't have a problem with imo.

Edit: i said eff it and picked it up. The batmowheel is $400 so this is a steal imo for my needs.

http://www.amazon.com/Holset-HE351CW-HE ... B00M9NJH1E
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Re: high boost pump gas question

Post by beercandrifter »

duncan351 wrote:Your motor won't built too much longer if you keep running that much boost on pump 93 octane. Its been tried and every time it ends up with a motor rebuild.
+1 Speaking from experience
was able to get to about 22lbs on my setup, ran 25 at my last track day on that build and messed up the pistons. Ran daily at 18psi in the 95* weather here
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25psi hx35/8.8:1/264^2 cams/95lb injectors/Megasquirt 2/ka24de build **RIP**
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Re: high boost pump gas question

Post by Greaser »

I hope youre still checking this thread.


I did some fuel testing for an "alternative fuel" corp that wants to replace ethanol (in e10 fuels)with GTBE. Heres some data.

my test car AT KNOCK limits on 93
10psi 240rwhp 11deg
15psi 250rwhp 5 deg

50/50 mix of his stuff and 93 AT KNOCK limits (+9 degrees)
15psi 300rwhp

100% of his stuff AT KNOCK limit (locked 22degrees)
15psi 307rwhp

So go get some tolulene from a paint store or spike it with like 5 gallons of e85 and play with it up at 25psi.
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Re: high boost pump gas question

Post by ViperGT »

haha chimming in a little late here. see you advanced timing from 9 degrees to 22 degrees but only gained 7hp this is dangerous and why we blow HG's and evo10s blow rods on e85, the cylinder pressure is increasing but the power is not, every degree of timing in increasing cylinder pressure but not power who cares about the 7 hp save your motor and take out that 11 degrees, i undersand you are runnign different fuels but all the same. e85 often wont knock, therefore you need a dyno to tune and you need to watch for when that extra degree stops increasing power as much as the last, eventualy if the motor will hold, the power will go down but your head studs and rod bearings wont be happy.
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