max boost on 91 octane ? 14 psi ?

[anconover]

most people rip em out. Thats the first thing i do on my, or friends cars when they get em.

 

[Budget90GST]

You're welcome. Since you're from CA, can you tell me what EGT's you're getting on your logger (the stock EGT for emission). Mine just now started moving past 110 F. I just wanted to see how high it would go in comparison to a standalone EGT (Pyrometer). Thanks in advance. Just PM me so I don't clutter this thread anymore.

 

[burldude]

Well here is an update . I bypassed that good for nothing fuel pressure solenoid , the dumb one on the fire wall . It was an improvement and it brought my knock at 12 psi to nothing, yes nothing . I was so happy I turned up the boost and since I have a mbc I didnt know what I turned it up to till I started putting my foot down . I hit 22psi pretty quick and backed off . I got a knock count of 22. Yeah 22 psi and and 22 knock , ha ha. I turned the boost down to 18 and got a knock count of 12 . So it improved but is still knocking with all the mods . I tried tuning the knock out by bumping the fuel pressure up 3 psi Still knocked . I then upped the safc trying to get the knock down and induced fuel stutter from running to rich . More to come................. I also have a fuel pressure gauge in car and I can watch it flatline and not build up to 57psi like I would like to see . I have healthy vacuum of minus 18 at idle so no problem there. Is it possible that Iam over running my fuel lines ? I am still seeing my o2 voltage drop from .88 to .84 and then .82 . I have a Cosmo Racing fpr anyone had any trouble with them ? I would think that a walbro 255 should keep up with 680's. Time to pull some timing ?

 

[out there]

are the maft's anything like the safc?

 

[burldude]

Thanks to everyone that helped out and gave there opinion . It turned out my fuel pressure solenoid was not allowing the boost to get through like it should . My advice is bypass that thing . Now I can run 18 psi and will get a little knock in forth gear running it at wot or close to it . I guess not everyone was conspiring to drive me crazy This was driving me nuts . My in car fuel pressure guage would show an increase but it wouldnt continue to climb . I figured it was just the pulse dampner . Now i have the 1-1 fuel pressure increase . Thank you everyone .

 

[AL92]

Hey guys thought would jump into this very interesting thread.I have some simliar things in my car.I have a new 50trim installed,650 injectors,afpr,maf,maft,palm.supra tt pump,
n1 catback and downpipe. I also have knock even running 10 psi on my 91 octane fuel .But I am 1900 altitude which should make the 91 act like 93.I get around 19 degrees timing at wot with the 10psi but of course not getting much speed compared to what could get at higher boost.
I have tried richer and leaner.I also didn't really see any .90 anything o2s. always under .9 but I also get that cutout thing happening at 5000 or so wot when I put the translator at 4 or so on the dial.I put it back to straight up and forget where the mid dial is think straight up too.Base is at 7 ltrims are very close to 100% like 96% and have some problems with ltrim have to crank up three or so notches to get it close to 100%.Seems it like 115% or 90%.I though my translator was screwed and have the new version chip in the mail coming to me.
But now I am going to try that fuel pressure solenoid.maybe its just fubared or something.Maybe they can stick closed and not work right.I get like 40 counts when go past 10psi and richening don't help and like I said I crank up my wot dial and it cuts like you guys.fact though it was my plugs so put in the colder brp7es but think they foul more at low speed than the stockers likely especially if you can't run high enough boost to clean them off.

I thought it might be my lack of fmic but still ran higher on my 14 b and thought the 50 trim actually don't heat up the air that much at 18psi compared to the 14b?
My car was never fast even with the boost cranked on the 14 and had similar weird tuning problems.
I did also do a pcv elimination the other day and thought that helped the knock counts
and might try it again .I took it off and went back to pcv as was getting lots of smoking on the side of car where had my catch can with breather but it turns out it was in fact coolant from loose thermostat housing.
This fuel pressure thing has my interest.I have only the gauge in engine compartment not
in cab.Its an easy thing to try maybe do it in couple minutes.I do drive car in winter so do you think will have problems starting and warming up with it disconnected? If so just get a new one or one from wrecker from car with lower miles.
I hope this works.10psi is ok on a 50 trim but 20 would be so much better.
Buddy is on here and he also has maft and same thing he could only run like 13 on his car he has 50trim same as me.He got a fmic and still says only 15 psi or so and too much knock.So mabye he needs to bypass his fuel pressure solenoid and do a check of things.
He will be in heaven if he can run 20 plus and so would I.I plan on fmic and alco injection system but still this could be a great idea if solenoid is fubar.

So now with your translator cranked up you don't get the cutting out stuff at wot since you did the fuel pressure bypass???

 

[burldude]

I have a stage 3 dsm chip and have the maft at the stock settings and let the chip do the rest . I have the Safc to fine tune with and the palm pilot datalogger . Get rid of the garbage fuel pressure solenoid , I dont think it was ever designed to handle overboost from stock or it is just a restriction . My problem got solved , thanks once again .

 

[burldude]

I just wanted to add that my fuel filter was another peice of ths puzzle . It would allow the fuel pressure to climb and then because I would see it get to where it needed to be I would go back to driving . It was a restriction only at the top of 3rd and up. I replaced that and now I have a knock count of 4 to 8 at around 4000 rpm and it is a brief knock count . I can live with it . I am running 17 lbs of boost and I think it is time for a bigger fmic. Once again thtnks to all ! I hope this thread saves somone the hassle I went through .

 

[paingod5150]

Where can I find a VFAQ or even general directions on bypassing the fuel pressure solenoid?

Three days ago my car started stumbling anytime that I began entering boost. This coincided with me nearly falling alseep on the way home from SF (to Sacramento) and going way to low on fuel in the tank. Wasent vapors but ###### into the tank trash.

What would cause the stumble and difficulty entering boost (sluggish spool) that could be caused by tank trash or does it sound like something unrelated?

Im replaceing filter-line-rail-inj-return shortly but driving the car is like NA at lower RPM.

Thats another thing, its fine at cruizing and high RPM and my gas mileage has IMPROVED (maybe because im scared to boost)

Thanks

 

[1992awdlaser]

Where can I find a VFAQ or even general directions on bypassing the fuel pressure solenoid?

http://www.dsmtuners.com/forums/showthread.php?t=198327&highlight=taboo+vacuum+diagram