How much boost can the RB20 take before running lean?

[Joe]

Your right. i dont know **** about tuning. i never have tuned my own car. i dont have the tools to do it. and i dont give a **** about the turbo in the car. and the 270cc injectors are good for 283 Hp at the crank at 100 Duty cycle. i know i dont have close to that much power well maybe at 19 PSI

100% duty cycle means you will blow your engine up.

[Carl H]

um, wow.you shouldnt own a car period.and the math for an i6's fuel requirements is 1cc = 1bhp, so 270cc injectors in theroy should support 270bhp at 100% duty.but you know when you run 100% duty the injectors tend to go static and either get stuck open or closed...good way to bend a rod or burn a hole.

[NizzansDET]

zer...36821

I just found those number off a chart.

[Carl H]

that chart assumes an na BSFC of .55, a turbo car will use a BSFC of .65 to be on the safe side.

[NizzansDET]

Oh. I see.how much does it cost to chip my ECU?

[SeVa-S13]

Wow, Blake showed up!

Always reading, rarely posting.

Honestly, 95% of the RB20 threads make me ashamed to be a 20 guy. =\

[SeVa-S13]

Oh. I see.how much does it cost to chip my ECU?

The term you're looking for is "socket."RB20(like early Z32 and CA18) ecu's are EPROM, which is great for DIY tuners. (I prefer a ZIF socket for easy swaps)

As for cost, it's free if you know wtf you're doing and have the right tools, and then all you really need is a laptop, cable, software (I use LiveEdit), and a ROMulator or EPROM burner. Oh, and of course a wideband like you already mentioned.

[NizzansDET]

how much does all the stuff cost? like a burner and what kind of cable? do you hook it to the ECU? or is it a pigy back? I just bought this car. dont know anything about it. i know how to take the head off and change the timing belt. i just changed the water pump. lol it has some problems. the stock manifold warped so bad i couldn't get it resurfaced. so i just got that ****ty *** EBAY manifold. its good for 100 bucks.My car has a EBAY Front mount. Peace of ****. the pressure drop is so bad. i put in a 255LPH fuel pump. the rest of it is stock. damn thing is slow tho. WHen i ran 19 lbs i got to 110MPH in the 1/4 mile. i run 12-15 PSI almost all the time. i just want to get to 12's the SR20 240 is faster then my car. probably cause i got 18's.

[Suicide.Veteran]

so the rb runs around a 14.7 A/F ratio in boost? I thought 14.7 was for idle and cruising out of boost and it's like high 11s to mid 12s for in boost? Of course this is based on knowledge of turbo KA's, + I have yet to hook up my wideband to actually see what kind of AFRs I have.

[NizzansDET]

no. your right... idk i dont have a wide band. thats next on my list. 14.7 is for idle and crusing. on boost it just dumps fuel in there. lol thats why it shoots cool flames! but 12PSI i get good gas milage then 15 PSI it gos through so much gas!

[Joe]

no. your right... idk i dont have a wide band. thats next on my list. 14.7 is for idle and crusing. on boost it just dumps fuel in there. lol thats why it shoots cool flames! but 12PSI i get good gas milage then 15 PSI it gos through so much gas!

your PSI has little to do with your gas mileage.

cruise/idle stoich (14.7) is normal, under load (any PSI above like 2, and any decent amount of throttle) you are going into a power mode and will get 12ish:1 afr's. thats normal, thats the way the world works.

[NizzansDET]

the more air you have... the more fuel you need. so it uses more gas. right? so lets say i am running 7Lbs then i turn my boost up to 30 i will get the same gas mileage? lol i dont think it works like that...

O and you have a sick drift car!!!

[nissanman04]

my head hurts

[Joe]

the more air you have... the more fuel you need. so it uses more gas. right? so lets say i am running 7Lbs then i turn my boost up to 30 i will get the same gas mileage?

O and you have a sick drift car!!!

but you arent going from 7 to 30, you are going from 12 to 15. BIG ****ING DIFFERENCE. your driving habits make more of a affect on mileage than a 3psi change in boost.

and thank you.

[NizzansDET]

I know. but im just saying. it would use more fuel. just a little bit! i noticed a difference.

[Carl H]

fuel consumption will go up, the purpose of a fuel pressure regulator is to mantain a 1:1 ratio underboost so for every psi of boost fuel pressure increaces 1 psi to compensate for the added pressure.this in theroy should keep afr's where they were originaly tuned at...works most of the time but there are exceptions.standard rb20 fuel mapping will dive into the low 10's at higher than stock boost, at 14psi my friends rb20 was nearly into the 9's under full boost; we leaned it out to 11.5:1 gained quite a bit of power according to the *** dyno and increaced fuel mileage back to stock (upgraded injectors at the same time).

[NizzansDET]

Damn you..... teach me how to tune!

[Chaos the Xile]

[RB280SX]

Sigh .

[devil_child]

wideband. The KA-T guys know a lot about doing your own tuning, go search through their stuff and check out ka-t.org for more info.

[Vkoslak]

FYI: I have 550cc injectors running 14psi of boost with a non-ceramic hks gt 2530 turbo a 300zx mass air flow sensor and a rich tune just so I don't blow stuff up.

Even with all that, the guys in the local Z club freak out if I mention I want to run more than 14psi on 93 octane.