another noobish question
10-08-2006, 08:45 AM
#1
0.5 BAR
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Join Date: Apr 2006
Posts: 66
another noobish question
I know it is noobish but luck of experience can be forgiven I believe.
here is the story - I have Civic 1.6L SOHC with built head with Cometic and ARPs, bottom end is stock.
I am running 0,6BAR (around 8-9PSI) in 1st, 2nd gear boos never goes higher than that, on 3rd it hits 0,7BAR, 4th 0,8BAR and on 5th it spikes up to 1 BAR, but always ater few secs it drops down to 0,6. Is it normal or my MBC is fked up? The rubo is T25. I don't want to blow my 1st build after 2 weeks of enjoing boost. thx
here is the story - I have Civic 1.6L SOHC with built head with Cometic and ARPs, bottom end is stock.
I am running 0,6BAR (around 8-9PSI) in 1st, 2nd gear boos never goes higher than that, on 3rd it hits 0,7BAR, 4th 0,8BAR and on 5th it spikes up to 1 BAR, but always ater few secs it drops down to 0,6. Is it normal or my MBC is fked up? The rubo is T25. I don't want to blow my 1st build after 2 weeks of enjoing boost. thx
10-08-2006, 10:13 AM
#3
0.5 BAR
Thread Starter
Join Date: Apr 2006
Posts: 66
Re: another noobish question
but it blows 1 bar wihile I don't want that much presure, I want 0,6BAR and it is there on lower gears why it spikes that much, can't be because of turbo maxed out - I am just using logic here, maybe it is because it takes time for WG to open and turbo to slow down spinning 
This turbo in saab blows 0,8BAR daily driver and was ment to be still effective at 1,2 bar
*edit*
wouldn't ECU gone in limp mode after seing such high amount of boost? I guess I need to check my gauge 1st
This turbo in saab blows 0,8BAR daily driver and was ment to be still effective at 1,2 bar*edit*
wouldn't ECU gone in limp mode after seing such high amount of boost? I guess I need to check my gauge 1st
10-08-2006, 01:00 PM
#5
0.5 BAR
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Join Date: Apr 2006
Posts: 66
Re: another noobish question
it is chipped PM6, 450s, car runs great, it pulls very, very hard for 500km now - I got pretuned ROM for similiar setup and just fine tuned for mine with LC-1. I am using 1,1* retard for 1PSI of boost and at 9 PSI my timing is around 19.3* - my spark plugs are somewhere between whitis/brownish (the ceramic parts of spark plugs).
I have checked logs and it shows max map value 18.16 which I believe is inHg what gives something around 0,6 BAR or 9 PSI if you like what I want.
Only gauge shows 1BAR (one BAR) but for some reason MAP don't see such preasure, besides wouldn't the motor be blown after pushing 14 PSI?
Don't know what is going on there - redone my gauge, checked for leaks - I will try new MBC, but if you have suggestions all are welcome.
I have checked logs and it shows max map value 18.16 which I believe is inHg what gives something around 0,6 BAR or 9 PSI if you like what I want.
Only gauge shows 1BAR (one BAR) but for some reason MAP don't see such preasure, besides wouldn't the motor be blown after pushing 14 PSI?
Don't know what is going on there - redone my gauge, checked for leaks - I will try new MBC, but if you have suggestions all are welcome.
10-08-2006, 01:48 PM
#6
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Re: another noobish question
Well It could just be your boost gauge. if your map sensor can read one bar and your lm-1 isn't showing you running lean or rich, and your not hearing detonation and their are no sighns of it on your plugs then I'd say your alright.
But I don't have near the experiance that Blasst does so maybe the boost spike is from that t25 being to small ?
switch out your gauge with another one and see if it reads the same. Check how you have the boost gauge hooked up make sure you don't have it t'd in with a bunch of other stuff.
But I don't have near the experiance that Blasst does so maybe the boost spike is from that t25 being to small ?
switch out your gauge with another one and see if it reads the same. Check how you have the boost gauge hooked up make sure you don't have it t'd in with a bunch of other stuff.
10-09-2006, 08:50 AM
#7
1.5 BAR
Join Date: Oct 2004
Posts: 877
Re: another noobish question
Well, can'T tell for sure until you tell us what your turbo exactly is but some t25 turbos can barely flow 150 HP. normal: They come from engines making 140 HP boosted!!
If your engine without any boost already produces as much hp than the turbo can support, then even with the internal wastegate fully open, there's so much exhaust pressure in excess of that WG capacity that the turbine still keeps accelerating to produce excessive boost, but since you get nowhere near enough flow, it may spool super quick and give you more power down low and at partial THR but will of course die on you at higher RPMS especially at WOT. That is, when it's time for your engine to make (or try to make) max power. in such conditions, a turbo doesn't last long. T25 ones are notorious for shaft failure when you push them too much.
So what is the turbo?? If it's a big t25(t2
from a skyline, you're fine. If it's half of a 300zx twin turbo set, then it's way small.
If your engine without any boost already produces as much hp than the turbo can support, then even with the internal wastegate fully open, there's so much exhaust pressure in excess of that WG capacity that the turbine still keeps accelerating to produce excessive boost, but since you get nowhere near enough flow, it may spool super quick and give you more power down low and at partial THR but will of course die on you at higher RPMS especially at WOT. That is, when it's time for your engine to make (or try to make) max power. in such conditions, a turbo doesn't last long. T25 ones are notorious for shaft failure when you push them too much.
So what is the turbo?? If it's a big t25(t2
from a skyline, you're fine. If it's half of a 300zx twin turbo set, then it's way small.
10-09-2006, 01:11 PM
#8
0.5 BAR
Thread Starter
Join Date: Apr 2006
Posts: 66
Re: another noobish question
It is Saab T25, .48 cold/.49 hot side - this turbo blows 180HP on 2L Saab engine or at least should.
I guess exhaust is weakest point here - 2" DP and all the rest is stock - I suspect this is my problem.
I guess exhaust is weakest point here - 2" DP and all the rest is stock - I suspect this is my problem.
10-11-2006, 06:30 AM
#10
0.5 BAR
Thread Starter
Join Date: Apr 2006
Posts: 66
Re: another noobish question
WG is fine, I tried free DP with no exhaust and it was running just great 0,6 bar almost to the redline - so as expected stock exhaust was way too restrictive.
BTW DP is 2,5" not 2" and stock is 1,75"
BTW DP is 2,5" not 2" and stock is 1,75"
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