can someone help me with this?

SON240sx Automotive
1

i’ve been doing searching around but still havent found a straight answer on how high i should turn my boost to, i recently jsut got a turbosmart single stage MBC (install help would be nice for that to thanks) and im not sure on how high i can put the boost up to SAFELY when i put it on cause i wanna do it soon. So here is a list of my engine mods done to my car to maybe help you tell me how high i can put it up to. its an 89 240sx with redtop sr20det.

Megan racing turbo manifold
twin chamber o2 housing
fmic with 2.5 piping(mounted behind bumper support, almost the size of the rad, bar and plate 3" thick)
HKS SS BOV
ported and polished head
cometic 1.3mm head gskt
multi layer steel intake and exhaust gskts
rocker arm stoppers
walbro 255 fuel pump
3 inch turbo back exhaust
GT28RS ball bearing turbo
mushroom style air filter
ngk iridium spark plugs
OPTIMA battery
s14 sr20det copper radiator and hoses
electric cooling fan
stage 3 6 puck clutch
95 180sx VLSD with 5 bolt axles

so hopefully this helps cause im not really sure what psi to go up to safely. thanks.

2

Turn the boost controller all the way down, do a few high way pulls to get an idea
of what the minimum you can run.

The turn it up to whatever you want. 12psi, 14psi, whatever.

3

I wont claim to know anything about the SR20 because I don’t. however, I do know things about fuelling systems and I do know a GT28r is considerbly bigger than a stock t28… that being said I wouldn’t just “put it wherever you want” I’d ask someone who knows about turbo maps that can compare what the stock fuel system can handle t28 wise then do the math to figure out what the gt28 will flow safely. your car is tuned to run a t28, you could probably get away with 14 lbs no problem on that but a larger turbo is a whole other story.

ask someone with a similar setup if theyd know, or take it to a dyno and do some pulls with a wideband and or egt and increase the boost after every pull until it becomes too lean or the egts get too high if you’re just using the stock fuel maps and no other tuning such as afc or standalone.

just my $0.02

4

I think Jedi has his injectors maxed @9psi boost on a GTiR SR turbo…

stock injectors? 10 would be my guess…

5

i just read somewehre though that the stock injectors could do 14 lbs easily… i dont htink that is very correct though

6

after i get my boost controller installed i want to get my car tuned… would getting an afc help me getting a better tune and getting the boost right?

7

14 lbs on what turbo? 14lbs on a t25 is far different than 14lbs on a gt28r

8

im not sure which turbo sorry. different turbo would make a difference on how much the injectors can handle?

9

HUGE difference… the more air the turbo flows the more fuel is needed… it’s about cfm, not just psi

10

so basically i just gotta experiment myself one or two psi at a time… how will i know when everythings good?

11

get a wideband before you cause some serious damage…or at least something to tell you injector duty.

i wouldn’t run that setup past 10psi without bigger injectors and a new maf.

Be safe or you’ll be kicking yourself.

12

would an afc tell me that to?

13

yes safc will let you run a larger maf, larger injectors(within reason like 550’s) AND tell you injector duty.

I would still use a wideband to be safe, but with 550’s and z32 maf with your seupt, 15+psi would be fine.

BUT like i said before, as you are now, i personally would not go past 10.

14

Actually Matthew… its the ACV-R which gives you an injector duty reading. SAFC1/2 will not. Maybe the new Neo will ? No idea…

15

ya ive been looking at the neo on enjuku and its like the same price as the afc and the neo is newer and does more… i think

16

what kind of wideband do you suggest?

17

Check this link.

http://forums.son240sx.ca/showthread.php?t=23478

18

Something that will datalog (like a zeitronix). As far as Im aware only way you can get any datalogging outta the AEM unit is if you also have the AEM EMS and thats huge money.

19

so for the uego you need the aem ems?

20

Nah, you just need to watch the gauge while driving, or have someone keep an eye on it for you while you’re boosting - to make sure the AFR’s are safe, that’s all. You need the AEM EMS to remember/store or “datalog” the information for looking at later if that’s what you’re looking for.

I would highly recommend the Uego, but then again i’ve never owned another wideband so… :stuck_out_tongue:

One other thing, i’d follow Lucky’s advice and stay below 10 PSI for now. Get it all set up correctly and then boost her guilt-free! :smiley:

Good luck.