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Old 08-02-2000, 02:38 PM   #1
Tim Prudence
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Question Safe boost level?

I have a MY99 5spd with Legacy turbo headers and turbo, 2.5" exhaust, and a small (pre MY97) WRX intercooler. Fueling is supplemented with a S-AFC, adjustable FPR (set at about 55 psi at atmospheric), and supra TT fuel pump. I get O2 sensor reading of around .900 when running at WOT, EGTs stay below 1600 F even when I redline it in 5th gear. ITC controls timing.

Question, I'm only running 5 psi off the stock wastegate now (actually it's more like 4 psi due to leaky wastegate, but it creeps up to 5-5.5 is higher gears). When I install my boost controller, what do you all think is a safe boost level with the equipment I'm running and my state of tune. I'm thinking that 7 psi should be ok (and still be plenty fun), but I thought I'd run it by you guys first.
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Old 08-02-2000, 03:14 PM   #2
kid22
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what's ur best times with that setup time, i wanna know, i'll be running the same boost
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Old 08-02-2000, 03:19 PM   #3
Tim Prudence
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I can get from home to work in 12 minutes with no red lights, that's my best time. Before the turbo, it was at least 15.

hehe, I haven't taken it to the strip yet... I don't know if I plan to either... I'll post times if I do though.
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Old 08-02-2000, 03:34 PM   #4
kid22
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HAHAHAHA
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Old 08-02-2000, 08:30 PM   #5
Ver.III
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I'de say 7psi to be safe and may be 10psi on short spirts but I'm not sure if the AFC can provide enough fuel above 10psi. An air fuel ratio gauge would help a little easier with tuning.
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Old 08-02-2000, 09:26 PM   #6
Tim Prudence
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The supra TT fuel pumps helps out quite a bit. Before I installed it I was getting O2 voltages around .880 at WOT with 55 psi fuel pressure (measured at idle/under vacuum); after the install I get O2 voltage of .900 at WOT with only 45 psi fuel pressure and less AFC corrections.

So I think my A/F is ok with only 5 psi, but an A/F gauge would be nice (along with oil press/temp).
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Old 08-02-2000, 10:28 PM   #7
MPREZYA
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Tim I really need to meet up with you about your setup. I have alot of ?'s and need to visually see some of the things you have done for my ideas.
Rich
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Old 08-03-2000, 06:46 AM   #8
Diz
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Question

"I get O2 sensor reading of around .900 when running at WOT, EGTs stay below 1600 F even when I redline it in 5th gear."

Redline in 5th gear, huh? It's way too easy to get in trouble when you have a turbo. Anyway, what are your ITC settings? I have a VERY similar setup to yours, minus the headers. I have yet to install the ITC. Thanks.

-Paul

[This message has been edited by Diz (edited August 03, 2000).]

[This message has been edited by Diz (edited August 03, 2000).]
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Old 08-03-2000, 08:05 AM   #9
SubieFL
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What does ITC stand for?
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Old 08-03-2000, 08:12 AM   #10
NickCat
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Ignition Timing Control
 
Old 08-03-2000, 08:12 AM   #11
Jay_UK
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Cool

Tim,

It is easy to know what ya max boost should be...

Keep increasing it until your engine blows... then minus one psi...

simple

J.
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Old 08-03-2000, 09:50 AM   #12
Tim Prudence
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Rich,

Drop me an email when you want to see it. I'm going to Vegas this weekend, but maybe next week.

Diz,

I'm retarding 8 degrees from 2400 rpms and up. But this is probably excessive as it is the same retardation as I had pre-intercooler (just went on). Haven't had a chance to tune yet.
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Old 08-03-2000, 01:08 PM   #13
Diz
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Cool

Thanks for the info, Tim. I appreciate it.

-Diz
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Old 08-03-2000, 04:07 PM   #14
TMR Impreza
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The AFC can't handle more than 10lb's?!?!?! Hmmm ask Adam or myself. I am running 5lb's more than when rich rode in my car. I'm at 16lb's And I feel I can sqeeeez out .5 more. But thats is as high as I am going. That it for me.
www.wonderlan.com/~hksupra
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Old 08-03-2000, 04:10 PM   #15
Tim Prudence
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Hey TMR, email me about your HKS EZ, I think I want it.
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Old 08-03-2000, 04:47 PM   #16
adam99rs
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I agree with Jay's theory, but that's ust me...I'm a bosst freak. I was at 17 for the longest time....had nerly identical readings as you Tim (O2 voltage was at .88, EGT's at around 700 C at redline in 4th and 5th). I say for longevity, stick with 1 bar.....it's plenty quick.
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Old 08-03-2000, 04:49 PM   #17
MPREZYA
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Hey TMR you know I want to get that stuff from you and we can see if your mom notices the difference LOL.
Rich
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Old 08-04-2000, 03:32 PM   #18
TMR Impreza
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Talking

The Only reason my car is still together at this boost level is because of the J&S Knock sensor. It has saved my poor old engine plenty of times. Adam, are you running the J&S? John, my web page is outdated, as soon as I get some time I will definately put you guys in there.
www.wonderlan.com/~hksupra

[This message has been edited by TMR Impreza (edited August 04, 2000).]
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Old 08-05-2000, 12:02 AM   #19
John at J&S
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TMR: That's a lot of boost to be running. Are you still using your J&S unit? I didn't see it listed on your site as one of your accessories. Please let me know if it's not working.
 
Old 08-05-2000, 12:39 AM   #20
MPREZYA
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John he is still using it when I rode in his car last Sunday. John if you could help me with a few quick questions I have on the J&S. I currently have one and I know that older ones use different programming and that J&S were going to program 5 degrees of retard at 4K or 5Krpms. Is their any designation on how I could tell if mine is one of them? Also has anyone installed one on a 1997 2.2L or am I going to be the first as far as you know?
Rich

TMR- I want to get those calipers and maybe we can swap the hoods so your mom doesn't notice .
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