is 17 to 20psi on the 450's too much for the injectors? Cuz as of now. I have no control of the spiking on my boost, which brings it up to 20psi for a second or two then back down to 17 to 19 psi..
max psi on 450's??
FWD98GST
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http://www.roadraceengineering.com/eclfuel.htm
So yes, it's too much.
Seems to me like you need to turn down your MBC a bit.
So yes, it's too much.
Seems to me like you need to turn down your MBC a bit.
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You could just buy race gas all the time hehe.
I was told no more than 15psi until 550+ were installed.
I was told no more than 15psi until 550+ were installed.
okay.. 17 to 19psi to too much.. so i should bring it down to 15 psi? what about 16 psi? still too much for the 450's?? i dont wanna harm the injectors by putting too much boost.. so i hope to fix it up.. but i still can't control my spiking on my boost...
i have no problem to boost at 16 to 17psi.. but on the other hand, this (all of a sudden) spiking problem i have is wierd... i would spike to 20 psi to come down to 15psi.. and when i play around with the MBC.. to hit 14psi, it would have to spike to 17psi.. isn't not a constant boost i have right now.. as of now.. im hitting 14 to 16 psi.. depending on hard i hit the throttle.. if i slowly hit the throttle to WOT on second gear, i would hit 14psi with minimal spike.. but when i floor it on second gear, it would spike to 17 to 18 psi, and settle around 15 to psi.. i have no boost leak at all, i tightend all clamps and checked all hoses 100%.. has anybody has this type of symptoms? if so.. what magic did you do to fix this spiking problem..
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I had a spike to 20 psi (t28 not big28)that stayed there w/ factory boost control, fuel cut was seen at about 4k. I have 15 psi now w/ a mbc. One of the ways to reduce a spike is runnung the mbc hoses as short as possible.
I see the reason you aren't hitting fuel cut is you have a afc. What are your settings?? I might not be a very good idea to use the afc w/ stock injectors unless you have higher base fuel pressure or know what your doing.
IMO, with the 190 rewired and a spike probably at 3500 I don't think it is very dangerous unless it stays at 20 psi until 4-5k...
I am planning on a similar setup with increased fuel pressure and fuel w/ a chip to get rid of fuel cut.
I see the reason you aren't hitting fuel cut is you have a afc. What are your settings?? I might not be a very good idea to use the afc w/ stock injectors unless you have higher base fuel pressure or know what your doing.
IMO, with the 190 rewired and a spike probably at 3500 I don't think it is very dangerous unless it stays at 20 psi until 4-5k...
I am planning on a similar setup with increased fuel pressure and fuel w/ a chip to get rid of fuel cut.
as for my settings on my AFC.. its all set to zero.. so it like default.. haven't touched anything yet.. so im holding off on that.. as for the hoses being short.. they are really short now.. and still have inconsistent boost..
B4 i had no problem with my boost.. ever since i tried to added more boost and my car buckled once.. i never can get a steady boost.. here's my problem..
Just recently, I'm having boosting problems on my 2g. My sig. below states my mods.. usually i was boosting 16 psi rock solid.. so one day i decided to turn it up.. and i was hitting 20 to 22 psi.. it was fine and one time my car buckled.. so i decided to turn it down to be safe.. no im having a hard time making my boost stay constant.. it would spike real high and stay constant.. for example.. in my 2nd gear.. it would spike to 20 psi then back down to 15 psi.. and 3rd gear would spike to 20 psi then down to 16 or 17 psi.. and 4th and 5th gear would spike to 20 psi and down to 19psi both.. i just want my boost to be back the way it was.. just pull up to 16psi and stay there.. not spike like 5psi before settling.. could be boost leak? damaged boost controller??
B4 i had no problem with my boost.. ever since i tried to added more boost and my car buckled once.. i never can get a steady boost.. here's my problem..
Just recently, I'm having boosting problems on my 2g. My sig. below states my mods.. usually i was boosting 16 psi rock solid.. so one day i decided to turn it up.. and i was hitting 20 to 22 psi.. it was fine and one time my car buckled.. so i decided to turn it down to be safe.. no im having a hard time making my boost stay constant.. it would spike real high and stay constant.. for example.. in my 2nd gear.. it would spike to 20 psi then back down to 15 psi.. and 3rd gear would spike to 20 psi then down to 16 or 17 psi.. and 4th and 5th gear would spike to 20 psi and down to 19psi both.. i just want my boost to be back the way it was.. just pull up to 16psi and stay there.. not spike like 5psi before settling.. could be boost leak? damaged boost controller??
Shit After installing my dave brode intercooler pipe, I was hitting 20 PSI solidly on my 14B... (on accident..) I haven't ever hit fuel cut before. I had the MBC set to 18 PSI from when I ran at the track, with 116 octane mixed in with some 93 octane amoco ultimate, and never hit fuel cut. The mix wasn't that strong, either.. like 2 gallons of the 116 mixed in with about 12 of the 93. I now turned the MBC down to 16 PSI to be safe, but you can't always depend on the computer to cut your fuel on a 2G. Maybe my car is just a freak or something but it seems like I'm always running rich, even with the stock injectors. (a little black smoke coming from the exhaust between shifts and such.)
"If you are running race gas when you are having fun or if you run higher than stock fuel pressure, you can get away with smaller injectors. East coast kids get 93-94 octane gas to play with, while the west coast gets stuck with diet light pretend 91 octane junk. Keep in mind also that living your life 1/4 mile at a time you will need less fuel than if you live your life in 20 minute run groups in open track sessions."Blackboost said:
Although, this guy is in CA, so he does have to deal with the crappy gas.
Do you have anyway to log your injector duty cycles? Well I hope you got a logger, because I was hitting 87-89% injector d/c with the t25 @ 15psi. After I installed my O2 eliminator and dp boost was spiking to 21psi! 
and my d/c was around 97%! FYI max recommended d/c is 85%.
and my d/c was around 97%! FYI max recommended d/c is 85%.This may be the case, but what were your 02 readings, EGT temps and knock sum? You do realize that fuel pressure is going to affect dutycyles as well...SiLow said:Do you have anyway to log your injector duty cycles? Well I hope you got a logger, because I was hitting 87-89% injector d/c with the t25 @ 15psi. After I installed my O2 eliminator and dp boost was spiking to 21psi!
I've regularly run 14B cars with 450s around 20-21 psi on pump gas with no ill effects in over 8 years. And yes, I've had dataloggers since back then as well.
From my logs without the O2 eliminator DP, @ 15 psi I was getting 0 - 2 counts of knock with the MAF reading air temps of 60 - 65 degrees F. I upped the fuel trims from 3500-7500 anywhere from 4% to 9% to eliminate as much knock as possible. During 80-90 degree air temps, i knock as high as 6 counts. On the log where I spiked to 21 psi, I was getting 10 - 12 counts of knock all over. My O2 readings @ 15 psi was around .94 to .96. I don't even pay attention to them because according to that I'm rich, but I'm still knocking a little. I've yet to conclude that any of it could be phantom knock because I hardly get any knock counts when the air temps are low. I don't have an egt gauge and I haven't upgraded or rewire my pump yet. A 255 and 660s are on the way. I hope these will allow me to push my t25 a bit farther.
It does? I thought dutycycles were calculated from RPMs and injector pw and that was determined by the ECU from airflow? I understand that if a pump can't feed enough fuel to the injectors, then at X pulse width it just wouldn't flow the amount of fuel the ECU had calculated?
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Like SiLow stated, the ecu don't know your fuel pressure is higher. It is your job to lean accordingly to match the correct mixture.DSSA said:
I'm not paying 500-600 for a avc-r to see my dc but I do have a tmo stage 3 like chip on the way that will let me see dc and also get rid of fuel cut. I can't wait to see it.
No, the ECU doesn't monitor fuel pressure per se.
However, upping the fuel pressure will allow you to tune the pw down and still attain the same fuel mixtures.
660s and a 255 are MAJOR overkill on your T-25. *MANY* people have maxed out a T-25 and 14Bs on stock 450s and an upgraded pump.
If you're maxing out 450s on a T-25 @ 15 psi w/ an aftermarket pump in there (and at .96 02 voltage), something's wrong.
Prime example is that there are low-12 second 14B cars out there running 450s.
However, upping the fuel pressure will allow you to tune the pw down and still attain the same fuel mixtures.
660s and a 255 are MAJOR overkill on your T-25. *MANY* people have maxed out a T-25 and 14Bs on stock 450s and an upgraded pump.
If you're maxing out 450s on a T-25 @ 15 psi w/ an aftermarket pump in there (and at .96 02 voltage), something's wrong.
Prime example is that there are low-12 second 14B cars out there running 450s.
If you have a HP walbro 255 or a supra pump with a stock fpr you will run rich enough to keep up with anything the 14b can push.
My car at around 17 psi will only see a little bit of knock in the last 100ft of the quarter.
On the other hand you have a 190 rewired so you would either need to raise your FP with an adjustabel fuel regulator or get bigger injectors.
My car at around 17 psi will only see a little bit of knock in the last 100ft of the quarter.
On the other hand you have a 190 rewired so you would either need to raise your FP with an adjustabel fuel regulator or get bigger injectors.
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