Jump to content
SAU Community

Recommended Posts

You'll find that the stock ECU starts to struggle long before the turbo itself is in danger (it will run to 14psi plus....probably....)

The stagea ECU is very conservative and will quickly run very rich and reduce the timing; you will notice this as more boost not making it go faster....and lots of black smoke.

So....if you want to run more than about 12psi you are going to have to do something electronic anyway (eg new computer or SAFC or fuel cut defender)

Here's 2 graphs from my car in the old days.....red line is stock (top line is power, dotted line is boost). black line is after installing a fuel cut defender.

stagea_dyno_boost.jpg

This graph shows why the power goes down like crazy; the stock computer was dumping in heaps of fuel (running rich) to protect the engine from what it assumed was an issue....see dotted red line which is the air/fuel ratio on the stock computer.

stagea_dyno_afr.jpg

  • Like 1
Link to comment
https://www.sau.com.au/forums/topic/456628-stock-turbo-psi/#findComment-7534150
Share on other sites

Where did you hear that info? Your Mum.

Why do you doubtimg it? Your Mum talks some shit.

Are you new to the internet? No, unfortunately I'm not. I do however see as to how you may have been confused regarding my prowess. Given I joined a topical forum, located the relevant Stagea discussion pages and I tried to make a general inquiry about said stagea like a tots newb. lol ;) #twat

Your not the first to raise the boost on a stock turbo. & I wouldn't be the first in given ya Mum some pounds per square inch either. (Tip: that's like a quite a lot, more than 3 bars even).

Link to comment
https://www.sau.com.au/forums/topic/456628-stock-turbo-psi/#findComment-7534207
Share on other sites

You'll find that the stock ECU starts to struggle long before the turbo itself is in danger (it will run to 14psi plus....probably....)

The stagea ECU is very conservative and will quickly run very rich and reduce the timing; you will notice this as more boost not making it go faster....and lots of black smoke.

So....if you want to run more than about 12psi you are going to have to do something electronic anyway (eg new computer or SAFC or fuel cut defender)

Here's 2 graphs from my car in the old days.....red line is stock (top line is power, dotted line is boost). black line is after installing a fuel cut defender.

stagea_dyno_boost.jpg

This graph shows why the power goes down like crazy; the stock computer was dumping in heaps of fuel (running rich) to protect the engine from what it assumed was an issue....see dotted red line which is the air/fuel ratio on the stock computer.

stagea_dyno_afr.jpg

Thanks mate for your helpful response, I noticed that the modest increase I gave it didn't necessarily equal the expected returns. Can see why this may be the case now.

Link to comment
https://www.sau.com.au/forums/topic/456628-stock-turbo-psi/#findComment-7534210
Share on other sites

I like the way you say you aren't new to the net but failed a quote edit.

Anyway, as Duncan kindly provided, and you figured out, just raising the boost on a stock ecu really isn't goiin to provide fantastic results.. As has been mentioned numerous times before.

Link to comment
https://www.sau.com.au/forums/topic/456628-stock-turbo-psi/#findComment-7534243
Share on other sites

The stagea ECU is very conservative and will quickly run very rich and reduce the timing; you will notice this as more boost not making it go faster....and lots of black smoke.

So....if you want to run more than about 12 psi you are going to have to do something electronic anyway (eg new computer or SAFC or fuel cut defender)

Had another look at your graphs and finding it a little odd that the fuel seems to drop so drastically (pre FCD) on basically the comparatively stock perimeters. While the Blue line is displaying a more even and greater power curve the two PSIs remain pretty equal. I would have assumed that at around normal performance the ECU/Injectors should be able to maintain load?

While I am not noticing any black smoke running at 10 psi, you mentioned that this may be because of the ecu retarding the timing & loading extra fuel, leading to injector failure. Wouldn't this extra fuel mean that it would be capable of simply providing the extra requirement? or is that the injectors are not able to maintain that load and essentially fail?

Is there any short term benefit to insure the exhaust flow is in turn increased, dump-Cat-mani-exhaust etc? Otherwise it appears that a ECU tune is really the best option.

Link to comment
https://www.sau.com.au/forums/topic/456628-stock-turbo-psi/#findComment-7534678
Share on other sites

Yep that's exactly the point....the stock stagea ECU is very conservative and does not like extra boost. FCD was a cheap and dirty fix, something like an SAFC would be a better idea for a car that is going to stay reasonably standard. Whole ECU replacement is a couple of grand no matter how you go about it.

Link to comment
https://www.sau.com.au/forums/topic/456628-stock-turbo-psi/#findComment-7534731
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Who did you have do the installation? I actually know someone who is VERY familiar with the AVS gear. The main point of contact though would be your installer.   Where are you based in NZ?
    • Look, realistically, those are some fairly chunky connectors and wires so it is a reasonably fair bet that that loom was involved in the redirection of the fuel pump and/or ECU/ignition power for the immobiliser. It's also fair to be that the new immobiliser is essentially the same thing as the old one, and so it probably needs the same stuff done to make it do what it has to do. Given that you are talking about a car that no-one else here is familiar with (I mean your exact car) and an alarm that I've never heard of before and so probably not many others are familiar with, and that some wire monkey has been messing with it out of our sight, it seems reasonable that the wire monkey should be fixing this.
    • Wheel alignment immediately. Not "when I get around to it". And further to what Duncan said - you cannot just put camber arms on and shorten them. You will introduce bump steer far in excess of what the car had with stock arms. You need adjustable tension arms and they need to be shortened also. The simplest approach is to shorten them the same % as the stock ones. This will not be correct or optimal, but it will be better than any other guess. The correct way to set the lengths of both arms is to use a properly built/set up bump steer gauge and trial and error the adjustments until you hit the camber you need and want and have minimum bump steer in the range of motion that the wheel is expected to travel. And what Duncan said about toe is also very true. And you cannot change the camber arm without also affecting toe. So when you have adjustable arms on the back of a Skyline, the car either needs to go to a talented wheel aligner (not your local tyre shop dropout), or you need to be able to do this stuff yourself at home. Guess which approach I have taken? I have built my own gear for camber, toe and bump steer measurement and I do all this on the flattest bit of concrete I have, with some shims under the tyres on one side to level the car.
    • Thought I would get some advice from others on this situation.    Relevant info: R33 GTS25t Link G4x ECU Walbro 255LPH w/ OEM FP Relay (No relay mod) Scenario: I accidentally messed up my old AVS S5 (rev.1) at the start of the year and the cars been immobilised. Also the siren BBU has completely failed; so I decided to upgrade it.  I got a newer AVS S5 (rev.2?) installed on Friday. The guy removed the old one and its immobilisers. Tried to start it; the car cranks but doesnt start.  The new one was installed and all the alarm functions seem to be working as they should; still wouldn't start Went to bed; got up on Friday morning and decided to have a look into the no start problem. Found the car completely dead.  Charged the battery; plugged it back in and found the brake lights were stuck on.  Unplugging the brake pedal switch the lights turn off. Plug it back in and theyre stuck on again. I tested the switch (continuity test and resistance); all looks good (0-1kohm).  On talking to AVS; found its because of the rubber stopper on the brake pedal; sure enough the middle of it is missing so have ordered a new one. One of those wear items; which was confusing what was going on However when I try unplugging the STOP Light fuses (under the dash and under the hood) the brake light still stays on. Should those fuses not cut the brake light circuit?  I then checked the ECU; FP Speed Error.  Testing the pump again; I can hear the relay clicking every time I switch it to ON. I unplugged the pump and put the multimeter across the plug. No continuity; im seeing 0.6V (ECU signal?) and when it switches the relay I think its like 20mA or 200mA). Not seeing 12.4V / 7-9A. As far as I know; the Fuel Pump was wired through one of the immobiliser relays on the old alarm.  He pulled some thick gauged harness out with the old alarm wiring; which looks to me like it was to bridge connections into the immobilisers? Before it got immobilised it was running just fine.  Im at a loss to why the FP is getting no voltage; I thought maybe the FP was faulty (even though I havent even done 50km on the new pump) but no voltage at the harness plug.  Questions: Could it be he didnt reconnect the fuel pump when testing it after the old alarm removal (before installing the new alarm)?  Is this a case of bridging to the brake lights instead of the fuel pump circuit? It's a bit beyond me as I dont do a lot with electrical; so have tried my best to diagnose what I think seems to make sense.  Seeking advice if theres for sure an issue with the alarm install to get him back here; or if I do infact, need an auto electrician to diagnose it. 
    • Then, shorten them by 1cm, drop the car back down and have a visual look (or even better, use a spirit level across the wheel to see if you have less camber than before. You still want something like 1.5 for road use. Alternatively, if you have adjustable rear ride height (I assume you do if you have extreme camber wear), raise the suspension back to standard height until you can get it all aligned properly. Finally, keep in mind that wear on the inside of the tyre can be for incorrect toe, not just camber
×
×
  • Create New...