Jaycar Boost and Fuel Control

[Jezboosted]

I too was considering doing a boost curve similar to this. I spoke to SK about this and he said that even though you're not running 12 psi at redline, there is no way to guarantee that you're not spinning the turbo too fast at middling revs. I suppose a reason for this could be that the very restrictive SMIC (on a Skyline, the Stageas are FMIC stock, right?) can start introducing an excessively high (3-5 psi) restriction above 10 psi @ engine, making your turbo work (and therefore, spin) very hard above 10 psi. Maybe something to be aware of? Or, you've calculated that it's OK?

Just wondering, how does it feel with boost tapering off? Does it make the engine feel a bit "dead" towards redline?

Also, have you noticed any reduction in fuel consumption, even when off-boost?

I really want to get my IEBC and DFA installed - I stuffed something on both kits and SK's still got them... so ATM I'm running on wastegate spring pressure (about 4.5 psi) and it's slooooow

I can definitely see what your saying about the possible pressure drop across the core of the SMIC. I am pretty sure I have read though that the standard S2 SMIC is R34 GT-T and can take 200awkw. I highly doubt i am even @ 150awkws. One plan i do have, is to put another boost gauge pre-SMIC for testing so i can see what the difference is.

I am so close to getting a fully stable map at top end, but i can still feel the RB power dip around the 5-6000rpm mark. Didn't gap the plugs yet, so that is this weekend now.

I filled up a full tank today, so i will let you know when it's dry what i got. I normally average 150 klms to each 1/4 mark on the guage so 600ks till refill so i will check that too. It feels so responsive and crisp now, I don't have to put the pedal down as far for hills ands overtaking on the hway is effortless in 5th gear just touching the throttle a bit more than you would cruising.

[DaveB]

wtf 600k's to a tank? lucky bugger...

[benro2]

I can definitely see what your saying about the possible pressure drop across the core of the SMIC. I am pretty sure I have read though that the standard S2 SMIC is R34 GT-T and can take 200awkw. I highly doubt i am even @ 150awkws. One plan i do have, is to put another boost gauge pre-SMIC for testing so i can see what the difference is.

I am so close to getting a fully stable map at top end, but i can still feel the RB power dip around the 5-6000rpm mark. Didn't gap the plugs yet, so that is this weekend now.

I filled up a full tank today, so i will let you know when it's dry what i got. I normally average 150 klms to each 1/4 mark on the guage so 600ks till refill so i will check that too. It feels so responsive and crisp now, I don't have to put the pedal down as far for hills ands overtaking on the hway is effortless in 5th gear just touching the throttle a bit more than you would cruising.

Well, from memory (and this was a loooong time ago so I could have it wrong), SK reckoned the R33 GTS-T's SMIC could drop as much as 4-5 psi @ >10 psi. I just did my own test on the dyno with an HKS Type S FMIC (a different car) and that was dropping 3 psi @ 15 psi boost (engine)!! I was very surprised at that but I suppose I'm getting better cooling so it's all good

So you're actually trying to hold 12 psi to redline?

Dayem, you're doing very well with fuel consumption like that! Is that with the DFA fitted? If so, what were you getting beforehand? On my R33 GTS-T (auto) I get about 400-450 km out of about 50-55L. That works out to be about 12.7L/100km on most tanks, which is definitely much worse than you! Also, that's driving pretty much like a granny (no point driving fast on 4.5 psi ) but it's probably considered "light" city driving, if there's such a thing... not so much sitting in traffic, just roads that are 50-60km/h limits with a few lights thrown in, and the odd 5 min cruise down the M4. The only time I'll beat that consumption is if I take a decently long trip which involves highway driving. My best tank was when driving to Melbourne where I got 9.3L/100km on 98 octane fuel but I've never beaten that - closest on subsequent trips (all highway driving) has been around 10.0L/100km but that was on 95 octane (which definitely increases consumption slightly).

I'm interested in finding out any ways to reduce fuel consumption as the GTS-T is my daily driver and even though I don't drive it *that* much, it would be nice to ease the load on the wallet by a few dollars per week!

[Jezboosted]

Well, from memory (and this was a loooong time ago so I could have it wrong), SK reckoned the R33 GTS-T's SMIC could drop as much as 4-5 psi @ >10 psi. I just did my own test on the dyno with an HKS Type S FMIC (a different car) and that was dropping 3 psi @ 15 psi boost (engine)!! I was very surprised at that but I suppose I'm getting better cooling so it's all good

So you're actually trying to hold 12 psi to redline?

Dayem, you're doing very well with fuel consumption like that! Is that with the DFA fitted? If so, what were you getting beforehand? On my R33 GTS-T (auto) I get about 400-450 km out of about 50-55L. That works out to be about 12.7L/100km on most tanks, which is definitely much worse than you! Also, that's driving pretty much like a granny (no point driving fast on 4.5 psi ) but it's probably considered "light" city driving, if there's such a thing... not so much sitting in traffic, just roads that are 50-60km/h limits with a few lights thrown in, and the odd 5 min cruise down the M4. The only time I'll beat that consumption is if I take a decently long trip which involves highway driving. My best tank was when driving to Melbourne where I got 9.3L/100km on 98 octane fuel but I've never beaten that - closest on subsequent trips (all highway driving) has been around 10.0L/100km but that was on 95 octane (which definitely increases consumption slightly).

I'm interested in finding out any ways to reduce fuel consumption as the GTS-T is my daily driver and even though I don't drive it *that* much, it would be nice to ease the load on the wallet by a few dollars per week!

So if the R33 intercooler drops 4-5 @ 10psi, and the R34GT-T one in my S2Stagea is slightly larger, i wonder if i have more pressure drop ? i guess it comes more so down to internal design.. Geez i better get the second boost guage on this weekend.

Well I WAS going to try and hold 12psi, but you now have me more curious about the pressure drop. I will not go any further with mapping until i hook up 2nd boost guage now.

The main things i can think of in comparing our fuel consumption is,

1. I have NEO Motor.

2. I have 68ltr tank.

3. I have 5 speed Manual.

4. 80% of driving is @ 100-110km/h on the highway.

I don't have a DFA yet, my A'Pexi pencil turbo timer says i'm mainly running @ 14.5 A/F when cruising, normal take off from lights etc. When the power is down it slowly drops to 11-12 as it revs out. Don't know how accurate a turbo timer is for A/F tho ?

Also i refill as soon as the fuel light comes on, and usually to fill it again is 58 litres. So i guess i am getting 600 odd k's off 58ltrs = 9.67ltrs per 100km. The S2 Stag weighs 1650kg too.

[benro2]

So if the R33 intercooler drops 4-5 @ 10psi, and the R34GT-T one in my S2Stagea is slightly larger, i wonder if i have more pressure drop ? i guess it comes more so down to internal design.. Geez i better get the second boost guage on this weekend.

Well I WAS going to try and hold 12psi, but you now have me more curious about the pressure drop. I will not go any further with mapping until i hook up 2nd boost guage now.

The main things i can think of in comparing our fuel consumption is,

1. I have NEO Motor.

2. I have 68ltr tank.

3. I have 5 speed Manual.

4. 80% of driving is @ 100-110km/h on the highway.

I don't have a DFA yet, my A'Pexi pencil turbo timer says i'm mainly running @ 14.5 A/F when cruising, normal take off from lights etc. When the power is down it slowly drops to 11-12 as it revs out. Don't know how accurate a turbo timer is for A/F tho ?

Also i refill as soon as the fuel light comes on, and usually to fill it again is 58 litres. So i guess i am getting 600 odd k's off 58ltrs = 9.67ltrs per 100km. The S2 Stag weighs 1650kg too.

I highly doubt you'd have *more* of a pressure drop at 10 psi. AFAIK the stagea uses a decently sized FMIC? That means that they can most likely design it so that there's less of a pressure drop at low boosts. There really only is one way to tell, though - and that's to use two boost gauges as you said. Also, I think the R33 is probably one of the more restrictive IC's around so the 10 psi rule really only applies to that particular car.

That's still pretty impressive that you're getting under 10L/100km from a 1650kg car! At a guess, if I did 80% of my driving on the highway, I'd be around 10.5 - 11L/100km.

I'm also very surprised that you're not hitting R&R at those boost levels! Also from memory, the RB25DET NEO's R&R is quite savage - in that you almost go through the windscreen when it cuts in, so you'd definitely know if you've hit it On mine, I have an indicated 9-10 psi @ 3500-4500 rpm when it cuts in, and probably cuts out again at 5000-5500 rpm but it's not head-through-the-windscreen style, just a few pops through the exhaust and a noticeable loss of power. I drove it around that way for a while since I *thought* both my kits were working properly and was waiting to visit the dyno to get the DFA tuned, but then I discovered that the DFA would consistently burn through a particular resistor... Now SK's got the kits and I'm waiting for them back - I've been running on 4.5 psi for AGES and can't wait to see some 10 psi goodness!! I worked out I'm down about 75kW @ flywheel...

[Jezboosted]

I highly doubt you'd have *more* of a pressure drop at 10 psi. AFAIK the stagea uses a decently sized FMIC? That means that they can most likely design it so that there's less of a pressure drop at low boosts. There really only is one way to tell, though - and that's to use two boost gauges as you said. Also, I think the R33 is probably one of the more restrictive IC's around so the 10 psi rule really only applies to that particular car.

That's still pretty impressive that you're getting under 10L/100km from a 1650kg car! At a guess, if I did 80% of my driving on the highway, I'd be around 10.5 - 11L/100km.

I'm also very surprised that you're not hitting R&R at those boost levels! Also from memory, the RB25DET NEO's R&R is quite savage - in that you almost go through the windscreen when it cuts in, so you'd definitely know if you've hit it On mine, I have an indicated 9-10 psi @ 3500-4500 rpm when it cuts in, and probably cuts out again at 5000-5500 rpm but it's not head-through-the-windscreen style, just a few pops through the exhaust and a noticeable loss of power. I drove it around that way for a while since I *thought* both my kits were working properly and was waiting to visit the dyno to get the DFA tuned, but then I discovered that the DFA would consistently burn through a particular resistor... Now SK's got the kits and I'm waiting for them back - I've been running on 4.5 psi for AGES and can't wait to see some 10 psi goodness!! I worked out I'm down about 75kW @ flywheel...

I've definitely got a SMIC, almost all turbo stagea's do. Series 1 have R33 IC, Series 2 have R34GT-T IC. It's mounted in the lower left of the front bumper with a duct and the air exit's through the wheel arch. It's only the RS260's that get FMIC due to RB26.

Thanks man, i'm pretty happy with the fuel consumption too Still got over a 1/4 of a tank of fuel and done 425km so far. Looks like 600k's again before light comes on.

I think i was hitting R&R when i had a sloppy map setup a week ago. I was accelerating up a hill going from 2nd-3rd and as boost was coming on up to around 10-11 psi at about 3000rpm it just died in a instant snap. I backed off the throttle instantly and continued mapping with windscreen intact .

I feel for ya mate being on only 4.5psi ! When i was setting up the IEBC I had the ECU still controlling the solenoid aswell, and could only hit 7psi - even that felt slow again. 4.5psi would be crazy. zzzzZZZzzzzz

[benro2]

I've definitely got a SMIC, almost all turbo stagea's do. Series 1 have R33 IC, Series 2 have R34GT-T IC. It's mounted in the lower left of the front bumper with a duct and the air exit's through the wheel arch. It's only the RS260's that get FMIC due to RB26.

Ahh right, I must be thinking of the M35 Stagea then?

I think i was hitting R&R when i had a sloppy map setup a week ago. I was accelerating up a hill going from 2nd-3rd and as boost was coming on up to around 10-11 psi at about 3000rpm it just died in a instant snap. I backed off the throttle instantly and continued mapping with windscreen intact .

I don't think your boost map (is that what you meant?) is sloppy, it's just your ECU responding to more air than it expects, so you'll need to get around this by using a DFA, but that will definitely need to be tuned on the dyno. As you know, you *want* as much boost as possible at as low rpm as possible, so 10-11 psi by 3000 rpm sounds pretty nice!

I feel for ya mate being on only 4.5psi ! When i was setting up the IEBC I had the ECU still controlling the solenoid aswell, and could only hit 7psi - even that felt slow again. 4.5psi would be crazy. zzzzZZZzzzzz

Hehe thanks I remember back when I had both kits on with crappy tyres going up a windy, steep road. After a hairpin, in the wet, I applied no more than about 1/5th throttle, in 3rd gear (in an auto, remember), maybe 2000 rpm and a good 5 psi - wheelspin, *on the straight*!! Sooo much torque with sooo little throttle - it was excellent, if a little dangerous in the wet!

[DaveB]

Hi all, need help asap - anyone know what the pin configuration of the 25-pin cable used to connect the IEBC to the hand controller is?

I keep seeing mention of "RS232" and "serial" but I'm pretty sure they're just referring to the connector which was commonly used on those interfaces, and the cable should actually be "straight-through" all pins connected 25-pin male-male?

I have the IEBC LED's lighting up and the hand controller display working fine but none of the switches on the hand controller do anything; shorting the high/low switch on the IEBC toggles the "(H)/(L)" on the display though.

Edited September 6, 2009 by DaveB

[KiwiRS4T]

You need the correct RS232 cable . People have tried various computer cables with a similar plug but they haven't worked. Do the fine tuning of the LEDs as per the set up instructions. When you have the unit connected to the car you need to turn the car off before switching between high and low or you can cause damage. Good luck.

[DaveB]

Thanks Robert, I didn't realise the ignition had to be off to change boost maps Just now done the fine tuning with the LED's... fingers crossed, but all seems to be working as the instructions suggest!

I did manage to trace my problem in the end; I had left out a wire link which connected the common side of all the switches to the cable

I've attached a picture of the link I missed out; it's not as obvious (to me) as the rest of the links because it is under the plug, and I missed it first pass (and second lol)

The cable I used is just a straight-through DB25 male-male (you can see it in the pic - just a couple of IDC type plugs on a length of ribbon cable). I hate how serial cables are always so confusing... so many different versions of the darn things - but I'm pretty sure that for it to be an "RS232" cable, it would need some fancy wiring - pins 2 and 3 crossed over, for instance, at the least?

This is just my experience with the cable though... straight-through works for me... BUT remember everyone, YMMV

Edited September 6, 2009 by DaveB

[BensDR30]

DB25 straight through is correct. A couple of things to remember with RS-232 are; pin assignments are in perspective of the DTE (computer) and cables are straight through unless named otherwise

[DaveB]

Thanks Ben, someone who knows something about rs232 I never heard of a straight-through rs232 cable before though? Always thought TD had to be to RD, CTS had to be wired to DTS or DTR or whichever one it is, etc etc?

[BensDR30]

That would be a null-modem cable you're describing.

[DaveB]

bloody null modem cables, there are 50 million kinds of those too...

so really, PC modems for instance (an example of a DCE?) which used to plugin with serial cables (usually 9-pin to 9-pin) - those cables are straight-through? But they didn't usually even have all 9 pins connected...?

edit: This is totally off-topic... but I just happened to notice in your sig. that you are using a water-air intercooler on your DR30... do you have a thread anywhere with any details of this cooler setup? I would love to do the same to my stagea...

Edited September 7, 2009 by DaveB

[lukebaldan]

Just had my 34 tuned at RE customs with the DFA. Managed to go from my previous dyno figure of 161.7rwkw to 177rwkw. AFR's are much nicer. Ray figured out the DFA fairly quickly, all up taking around 45 minutes. Very happy with the results, high end response is significantly better.

[BensDR30]

bloody null modem cables, there are 50 million kinds of those too...

so really, PC modems for instance (an example of a DCE?) which used to plugin with serial cables (usually 9-pin to 9-pin) - those cables are straight-through? But they didn't usually even have all 9 pins connected...?

edit: This is totally off-topic... but I just happened to notice in your sig. that you are using a water-air intercooler on your DR30... do you have a thread anywhere with any details of this cooler setup? I would love to do the same to my stagea...

Correct regarding the DB9 cable, and I'll PM you re: the IC.

[DaveB]

Hi all,

Just an idea... this has probably been mentioned before. Regarding the vent hole size for the IEBC. I found that the S2 one seems to be about 2mm which, according to the tuner, is same as R34 (which would make sense )

Thing is, I think 1mm would be closer to ideal for my setup, because currently my solenoid comes on at 30% at load point 10, has to do 70% duty cycle by load point 34 and it's at 100% by load point 50.

A couple of guys have used some sort of adjustable venturi valve, which sounds ideal. But I don't know where to get one and the hardware places I've asked have no idea what I'm talking about (makes sense cause I don't either!)

I thought about it and it really just needs to be a basic tap/faucet type device, no? Just a valve which restricts the size of a hole, regardless of the shape? The closest I have found was a watering system dripper, which was cheap but was neither durable or I would think reliable since the slightest knock/warp from heat and the hole size would change dramatically. Plus not a very fine range of adjustment.

Soooo I was wondering, the old "boost tee" turbo-smart style "boost bleed" valves, which at one stage could be had for like 30 bucks (but now are all around $80-90 on ebay wtf???) weren't they just a tap with a very fine range of adjustment? Or did they have something else fancy to them?

An example of the device I'm talking about (this is a new one off ebay so I don't know if it is different to the old ones).

...what do you think, cheap & very convenient way of adjusting vent size? Or not suitable?

Edited September 20, 2009 by DaveB

[KiwiRS4T]

I am using a brass needle valve available from enginering supply stores (You will need a male/male one or if it is a M/F or female/female you will need one or two "tails" to push the hoses on). It allows for very fine adjustments.

However it is not very "stealth" and I plan to replace it with a simple restrictor. Some people use the ends of gas welding tips because they have a known size but i am probably going to fill one end of the T with solder and drill it out a bit at a time til its right.

[DaveB]

Ah, something like this?

http://www.fnwvalve.com/FNWValve/prodDetai...OCK_ID=10000868

That doesn't look too bad... pretty small... and yeah the range of adjustment is important obviously must be as fine as possible; and I remember people saying that the mechanical boost controllers/bleed valves were very fiddly ie. small adjustment made a big difference.

Is your brass valve too bulky? Could you perhaps cable-tie it up out of the way somewhere under something?

[KiwiRS4T]

Yep that's the one. Take some hose with you to get the right size fittings. Actually you don't see my needle valve at first - it is pretty much hidden under the snorkel.