Max boost on 91 octane?
#1
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Max boost on 91 octane?
Hey guys,
I'm running a stock port S5 13BT with a TO4B 60-1, .96 rear, .70 comp housings. It's a P-trim exhaust wheel.
I have the car running about 15.5 psi at the moment, and have taken it up to 18 psi (feels really good ). I was wondering how much I can jack up the boost on 91 octane fuel. If possible, I'd like to run 20psi. Does anybody know approximately what timing I'd have to run to pull this off? At the moment I'm at about 15* BTDC with ~13* split at 15psi (I believe). AFR is right around 11-11.5:1. Also, I've got a decent IC (NPR front mounted), so intake temps are <120*F (50C) at pretty much all times.
Thanks!,
Manolis
I'm running a stock port S5 13BT with a TO4B 60-1, .96 rear, .70 comp housings. It's a P-trim exhaust wheel.
I have the car running about 15.5 psi at the moment, and have taken it up to 18 psi (feels really good ). I was wondering how much I can jack up the boost on 91 octane fuel. If possible, I'd like to run 20psi. Does anybody know approximately what timing I'd have to run to pull this off? At the moment I'm at about 15* BTDC with ~13* split at 15psi (I believe). AFR is right around 11-11.5:1. Also, I've got a decent IC (NPR front mounted), so intake temps are <120*F (50C) at pretty much all times.
Thanks!,
Manolis
#4
blew my motor doing several runs at 1.3 bar with 91 octance. i was trying to fix a non-regulating boost problem and left off the gas as soon as I saw the boost needle creep past 1 bar but i guess my foot reaction wasn't fast enough. keep it at 1 bar. t51rkai/nb apex seal motor. very costly mistake for me.
#5
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i am a regular 1.15 bar driver on 93 octane. 20 psi is the max i have ever allowed it to go on pump gas but i have a t78 and a huge front mount intercooler so my charge air isnt really overheated.
#6
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ExFasWS6: Yeah, I've got a nice FMIC too. Last night playing around on the freeway my intake temps never got over 97*, and dropped from that to 71* in 15 seconds (!) doing 80mph. I think I'm going to up the boost to 1.15 bar (16.5psi) and leave it there. If I want more than that I guess I'll look into water injection or something. I have the Haltech tuned so it goes crazy rich (richer than 10:1) over 16-17psi, and doing 60-90 runs at 16psi yielded better results than at 18psi The runs, btw, averaged ~3.5 seconds, with the best at 3.45. This was done with a passenger. Z06 here we come
Thanks,
Manolis
Thanks,
Manolis
#7
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20 psi is waaay to much for pump gas on a rotary. You will blow up. Spend the extra bucks on race gas or spend alot more when you blow up. Some get away with running 18psi and water injection and that helps keep it relatively safe, but 91 octane is **** water and you will detonate sooner or later.
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#11
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I have gone as high as 19psi on 91 octane with some magic elixir (octane booster), but the a/f's were also way rich in the 10.5:1 range.. I wouldn't do it with straight 91, in fact on unknown everyday gas I hold back to 12-14 psi as my safety margin, sometimes what you think is 91 is actually 87, and Premium on the pump is a relative term, premium compared to what, is the question...
Recently I burnt a tank of 94 octane, running 19 psi, no problems..
My timing is around 13 degrees at 15 psi, and starts tapering up slightly as the rpm's climb past 6000 rpm..Max
Recently I burnt a tank of 94 octane, running 19 psi, no problems..
My timing is around 13 degrees at 15 psi, and starts tapering up slightly as the rpm's climb past 6000 rpm..Max
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Originally posted by Resource
Why are you guys using 91 and not 93?
Why are you guys using 91 and not 93?
#20
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for ***** and giggles, here's the link to the homebrew gasoline additive site.
* i have no experience with this and do not accept any responsibility for anyone's misfortunes*............ but let me know if it works
http://www.vtr.org/maintain/gasoline-octane.html
* i have no experience with this and do not accept any responsibility for anyone's misfortunes*............ but let me know if it works
http://www.vtr.org/maintain/gasoline-octane.html
#21
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Originally posted by REFD3S
blew my motor doing several runs at 1.3 bar with 91 octance. i was trying to fix a non-regulating boost problem and left off the gas as soon as I saw the boost needle creep past 1 bar but i guess my foot reaction wasn't fast enough. keep it at 1 bar. t51rkai/nb apex seal motor. very costly mistake for me.
blew my motor doing several runs at 1.3 bar with 91 octance. i was trying to fix a non-regulating boost problem and left off the gas as soon as I saw the boost needle creep past 1 bar but i guess my foot reaction wasn't fast enough. keep it at 1 bar. t51rkai/nb apex seal motor. very costly mistake for me.
ouch..arent those as much as ceramics.
any impressions on them? Dont know anyone in north america who is using them.
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