Safc And Boost

[pixel8r]

Hi guys,

Just purchased a turbotech boost controller off ebay (there's a long thread on this forum about them with very positive feedback).

At the moment I have a JRD one (also off ebay, same design as the turbotech). Quite simply, I'm not 100% happy with the JRD and want to try the original turbotech that has worked so well for many other people on this forum.

What I want to know is, how will the changeover affect the SAFC/tune?

ie. If I run less boost now than before, will it run too lean? and vice versa?

Just not sure if I can realistically change the unit over without requiring a re-tune. I plan to run the same 11-12psi that its running now, but if the turbotech holds 11psi at the redline, that would be 2psi more than the current boost controller. I'm not sure what to expect.

If it requires a retune then I'd be better off just leaving it alone until I have a more significant modification worth tuning (ie. FMIC or something).

Any thoughts?

[yokotas13]

if you run less boost it iwll make it richer on your tune

if you run more it iwll be more lean

however, im sure your tune isnt 100% accurate as most SAFC tunes arent.

[pixel8r]

I kinda felt that it would work the other way. Let me explain...

In my experience with turbo nissans, the ecu is designed so that as it detects more boost/airflow it will keep dumping more and more fuel in until it thinks the fuel system cant keep up, at which point it will hit R&R (failsafe fuel map) to protect the engine. The SAFC only moves the airflow signal up or down by a percentage (as far as i know) so this wont change the actual built-in behaviour of the nissan ecu.

In other words, more airflow (or boost) would normally mean more air/less fuel except that the ecu is programmed to increase the fuel as it detects more airflow, thereby preventing it from running lean. It usually goes to extreme levels to do this, hence why most skylines/stageas run stupidly rich with just an exhaust and more boost. If the opposite were to also be true, then lowering the boost would cause my SAFC (with its current setup for 12psi) to overcorrect too far and lean out the mixtures too much, which is what I'm most concerned about. Also how much would the boost curve need to change for it to throw my tune out of line?

I could adjust the SAFC settings myself to make it "safe" but this would only be a temporary measure until I get it tuned. Not really worth it IMO. All I want from the new boost controller is a bit more responsiveness and more reliable boost, but if its going to require a re-tune then I wont worry.

I'll admit I'm no expert on the whole thing but the above is as I understand it.

[yokotas13]

Buy yourself a wideband

and see what happens

[yokotas13]

Buy yourself a wideband

and see what happens

[Tangles]

just add say a 2% correction throughout the hi-load map.

I had to add 5%-6%-4% from 4000rpm thru to 7400rpm on saturday, car was pinging up there, and now she's not

[ssshonky]

dont forget that you can really only get limited tuneability with the SAFC.

As when you add Boost it retards timing. ( from my understanding of it all ) I think thats why

you need another computer to control timing ( SITC? ) that way you have a lot more room to move when your trying to get optimum timing/AFR settings

[Tangles]

yeah, on my trial run up and down a 80kmph road, I noticed after adding safc correction up high, that it seemed lagier at 4000rpm exactly.... so I toggled the 4000rpm sitc switch a bit and adjusted it on the fly, seems ok. cant hear any audible knock - although this is a temp measure until I can get the final tune done.

(have oil filter relocator and adjustable cam gear to go in, and tune to 1bar, PLUS bushes Ive had for a year PLUS front rotors Ive had for a year, damn the fact that I cant kneel to do it myself. sux)

[pixel8r]

Not sure if people are reading this correctly.

My SAFC is already correctly installed and properly tuned for my current boost controller, set at 11-12psi, but the boost controller cant hold boost well and it drops off to 9psi at the top end.

What I want to know is if it will damage anything if I replace this boost controller with another one - different brand, same type of controller (search for $22 boost controller in the forced induction section).

All that will change boost-wise is that it may hold boost better, therefore giving me 2psi more boost at high rpms. It may also boost up quicker when changing up gears but I dont think this would affect the SAFC tune.

So can anyone confirm for me if raising boost means I need to increase the correction values in the safc or decrease them? and the opposite for lowering boost should obviously apply as well.

I'm also assuming that if I take the SAFC back to zero correction the car will hit R&R as it did before the SAFC was installed. The SAFC is correcting the AFR's from ~9:1 back up to a more efficient 12:1.

Any tips on how to make sure the boost controller swapover is done safely? or should I not bother with it? I'm really hoping to get more consistent boost and more responsiveness from the turbotech controller.

As a side note, with the stock fuel pump and injectors, whats my limit as far as awkw/boost? I've got ~160awkw now - is there any room to improve this to say 180awkw with a FMIC and more boost? Not saying I'd reach that but I just want to know where my safe limits are before I require an upgraded fuel pump or fuel pressure regulators. It might be worth my while getting another tune...

[yokotas13]

do you realize the leaniency that your Computer allows?

put the boost controller on

Run the piss out of it, see your AFR values, if they get to lean in said process, back off, add a % or two and go at it again

[ssshonky]

I would say that any info given to you here is strictly on a " all care no responsibility clause"

I would think its safe to run the boost controller without a tune

just monitor boost carefully as those boost controllers are EXCELLENT but very hard to get right.

1/2 a turn can bump the PSI up pretty drastically.

oh and make sure you tighten the nut after you set it.. as my bolt fell out when I had one of those before.

but yeah.. in summary.. I would be very surprised if that did any damage.

just take the adjustment of the boost level very carefully. and watch the guage carefully to make sure it does not go to some stupid amt of boost

[pixel8r]

I would say that any info given to you here is strictly on a " all care no responsibility clause"

I would think its safe to run the boost controller without a tune

just monitor boost carefully as those boost controllers are EXCELLENT but very hard to get right.

1/2 a turn can bump the PSI up pretty drastically.

oh and make sure you tighten the nut after you set it.. as my bolt fell out when I had one of those before.

but yeah.. in summary.. I would be very surprised if that did any damage.

just take the adjustment of the boost level very carefully. and watch the guage carefully to make sure it does not go to some stupid amt of boost

Yeah I know what you mean.

Thanks for the hints on setting up the new boost controller. I didn't install the last one because I needed the SAFC installed and tuned at the same time so I just had the workshop do it. But seeing as this will be a straight swapover it shouldn't be too difficult. The boost controller comes at the "low boost" setting so I can just use small adjustments from there until I get it right.

I do have a boost guage but its not permanently wired in. I just connect it up when I want to use it and run the line through the window.

Once the boost is set and the nut is tightened it should stay at the same boost (touch wood).

I'll get the boost guage installed someday but I'm not handy with stuff like that so I need to get it installed by someone who knows what they're doing. If I did it it would look terrible

[pixel8r]

Apologies for posting again so soon, but just rounding up on this thread...

I'm happy to say the operation was a success and I'm now running roughly the same boost as before (11-12psi) and it seems to be holding boost a lot more solid. Yay!

If anyone's looking at this type of boost controller, my advice is to steer clear of the imitations, and go for the "original" turbotech one.

[webng]

Apologies for posting again so soon, but just rounding up on this thread...

I'm happy to say the operation was a success and I'm now running roughly the same boost as before (11-12psi) and it seems to be holding boost a lot more solid. Yay!

If anyone's looking at this type of boost controller, my advice is to steer clear of the imitations, and go for the "original" turbotech one.

Good to hear! Mine's in the post. Along with Pivot boost gauge I got 2nd hand from the ns.com forums, i'll get Boostworx to install them when i get the car tuned next fri... I'm not much of a home mechanic although i do try. I'm aiming for 9psi/0.62bar so the occasional spike to 11psi won't kill my standard turbo!

[Tangles]

get the fuel pump, and adjustable nismo fuel pressure regulator, if you are after 180awkw.

just my opinion only, thru info I have gathered off this site and from SK.

as said, I dont see the harm in adding a small amount of correction to the safc if you are worried about the afr's. running rich for a month or so, prior to fitting fuel pump / adj.fpr and tune, isnt a huge cost in the long run. good luck with it mate

[pixel8r]

get the fuel pump, and adjustable nismo fuel pressure regulator, if you are after 180awkw.

just my opinion only, thru info I have gathered off this site and from SK.

as said, I dont see the harm in adding a small amount of correction to the safc if you are worried about the afr's. running rich for a month or so, prior to fitting fuel pump / adj.fpr and tune, isnt a huge cost in the long run. good luck with it mate

Thanks buddy. Was just a thought I had...you know when you get some new go-fast part for your car, and you then start thinking "now what if I ALSO got this and this and..."

I've bumped the boost up a little more and it definitely feels slightly quicker than before. Car seems to have no trouble at all keeping up with fuel etc. and cant hear any pinging noises or anything. It just goes! I'm guessing its probably around the same mark as before but could be holding the boost at 12psi instead of dropping back to 9psi like the old one did. The old one gave a big flat spot in the power curve around 4000rpm due to the boost dropping off sharply from 12 back to 11psi.

When I first installed it the boost was at about 8psi but I've since turned the screw in about a 1/4 of a turn or so, hoping to get it up around 12-14psi. Since I have an aftermarket turbo, my only real concern is if the fuel pump/injectors can keep up. And at the moment they're doing just fine. I may look at getting another tune (and maybe an fmic) before summer tho...

I think its probably quick enough as it is. I know I'd like to have 180 or even 200 kw at all wheels but I also know that I have trouble forcing myself to drive sensibly now...

[Tangles]

yeah with your big monster turbo, when you go back for a tune PeRsOnALy Id install the Nismo adjustable FPR (nengun, $160 delivered) and a larger fuel pump (bosch 040, $200 delivered)...... "just in case". comes down to desires/wants and affordability tho.

but then youd know deap down the car would forever be "safe", once tuned.

with 190awkw (next tune expecting the 200awkw mark with the cam gear pulley and higher boost) I know I dont flatstick it, Im a safe driver and obey all suburban speed limits - just when I want to give it a poke, well, i can, and she responds so well; makes it a pleasure to own.

but yeah, we all reach a point and say "No More Mods" and thats that.

find your point young padwan. next tune is mine

[bumble_bee]

so let me get his rit...

VCT would kick in around 5500ish? rpms...

and boost would be around 3000rpms..

so more fuel is required around here...

and ive been lead to believe that around 4000-6000rpm's is wen and R&Rs would kick-in..

so the ecu would dump more fuel in...

so on the afc..

u would drop it around -5% through-out that rpm range on high throttle..

so Tangles..did u put more fuel in?

thats probably why ur car felt a bit laggy..

try doing it my way..

and she how she feels..

[KiwiRS4T]

so let me get his rit...

VCT would kick in around 5500ish? rpms...

and boost would be around 3000rpms..

so more fuel is required around here...

and ive been lead to believe that around 4000-6000rpm's is wen and R&Rs would kick-in..

so the ecu would dump more fuel in...

so on the afc..

u would drop it around -5% through-out that rpm range on high throttle..

so Tangles..did u put more fuel in?

thats probably why ur car felt a bit laggy..

try doing it my way..

and she how she feels..

Of course people can do whatever they like with their own cars but I would never advise anyone else to change their timing or afrs without some means of detecting knock or measuring afrs because a mistake - too much advance or too lean - and "bang"! hole in piston = new engine.

[Tangles]

tuned always on a dyno by a pro, and then Ive changed a cple areas in high rpm 5500+ for fuel and timing

having a safc and sitc means its easy to change obviously, BUT, a year on I now also have a Toshi ecu remap

so now my safc is reading Negative -15 thru a fair whack of the rpm range.

plenty of fuel left in it, next tune is mid december (drop off the stagea for head port, poncam install & tune start Dec.)

200kw at the moment

230-240kw in 6 weeks time

the safc will be brought back up into the positives

all I can say is the Stagea is sooooo awesome to drive now as she is, so beautiful, but the head work and tune will make her more of a beauty Im sure