Supercharged/TurbochargedThe increase in air/fuel pressure above atmospheric pressure in the intake system caused by the action of a supercharger or turbocharger attached to an engine.
Welcome to Maxima.org!
Welcome to Maxima.org,
You are currently viewing our forum as a guest, which gives you limited access
to view most discussions and access our other features. By joining our community, at no cost, you will have access to start new topics, reply to conversations, privately message other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join Maxima.org today!
I've got a VQ30DE+T setup in my Cefiro using the stock Gloria VQ30DET turbo (at ~8psi) and VQ30DET injectors (which I believe are 370cc). I'm currently using the stock VQ30DE ecu with a SAFC II to keep the AFRs in check. I'm worried that my ignition timing is going to be way too advanced and that the engine will destroy itself from detonation. The SAFC is currently set to ~17% reduction.
I was wondering if anyone had any solutions to turn down the ignition timing for a build on a fairly tight budget.
I've heard good things about the J&S safeguard, but after you factor in international shipping (i'm in New Zealand) + currency conversion + local tax (+12.5%) it's a bit out of reach for me. I could try and source a second hand e-manage blue, but I'd probably have to fork out a fair bit for harnesses etc also.
I've thought about using my consult cable to try and reduce the base timing using the active tests, but I don't think that it sticks after the engine is shut off. Bare in mind, that being an pre-facelift cefiro, I'm on OBD I.
That -17% correction is definitely going to add in some timing, you'll hit the knock sensors at the least I bet. If cost is really an issue you can get the 370cc's tune better with a Z32 maf and an FMU with a really small disc ratio (like 3:1 IIRC) and a AFPR, and then fine tune what your left with via fuel pressure and then your safc. You'll want to do some research on this method or ask someone with more knowledge than me (ie someone who has personally done it). But the preferred method anyways would be to get something a little better like the E-blue or ultimate to scale the injectors back without affecting timing, and you'll have timing control as well. Or stock injectors and an fmu will give you a stock off-boost tune and won't effect timing under any conditions, but you will have to live with low 10 a/f's in the midrange and the possibility of locking up an injector and unsafe fuel pressures.
__________________
Gatorade on my keyboard FTL.
5th & 5.5 gen VLSD Auto transmissions for sale, PM me.
That's all a lie BTW, the truly preferred method would be for one of us to send you an obd-II ecu, see if you can get it to work in your car, and then bring it to throttlehappy46 and find out if he can really chip & tune one of our ecu's I will donate the ecu & pay to get it in your hands.
Two ways, upgrade to an emanage blue to control timing and a/f independantly, or the easy way with an adjustable FPR.
What's your fuel pressure set to? If you have an adjustable FPR you can drop your psi a bit so you dont have to remove as much fuel with the AFC (say if you run 370s @ 43psi [3Bar] @WOT, you can drop that 4psi to 39psi and still get good atomization. Idle quality Im not so sure about because that would place idle psi at 30, which with 370s may or may not be enough for a smoother idle. Trial and error works here lol).
I personally suggest to have both. For tuning it makes life a lot easier to adjust PSI to get you in the general area you want to be in, then go in with whatever piggyback you want to use to fine-tune it. It is much easier, and more reliable to do it this way than to solely rely on one.
__________________
Guys I need money to recover from my recent engine build (it wasnt by choice LOL). Im selling a Holset turbo if you are interested
Agreed, I believe they have a gloria VQ30DET application.
Beyond that, the quick and dirty way would be to drop the fuel pressure some, meaning you would have less negative correction on your SAFC (thus reducing the inadvertent timing advance that is applied when you pull fuel with SAFC). If you can drop it low enough you might be able to actually get in to a situation where you have to ADD fuel with SAFC, which would cause inadvertent timing retard, which would not be a bad thing.
Honestly though if you can just get it back to stock timing you'd be just fine. I believe you guys have higher octane gas down there than in the states, coupled with the fact that you have 9:1 compression pistons and a pretty small turbo, you would be just fine running stock VQ30DE timing in my opinion. Guys have run more aggressive setups (larger turbos with USDM 10:1 compression) and not had knock problems (my friend i30tmikeD would be one of those people).
__________________ 95 SE - Stock 3.0L w/ USIM - T61/P-trim @ 14.5psi - 93 octane
11.76 @ 121 - 1.82 60' - ET Street DOTs
12.15 @ 123 - 1.95 60' - Nitto DR 3.5L swap with I/Y/E
12.92 @ 104 - 1.69 60' - M&H Slicks
13.60 @ 103 - 2.15 60' - Street tires
Cheers for the replies. I'm actually running vq30de+t rather than the vq30det. After pulling off the cam covers I found the vq30det was completely sludged up, so I'm just using the manifolds/turbos from it. One day I might use the pistons/rods/crank from it and stick it into a vq30de, but for now I'm sticking with the +t.
Which MSD part number would I need? there seems to be thousands of variations.
I thought about reducing the fuel pressure - but if I was to reduce it back so that I'm on 0 on the safc - I'd imagine i'll be only running around 35psi?
Cheers for the offer on the OBDII ecu - but personally I quite like the OBDI as it doesn't seem to complain that I've removed all the emissions crap (EGR, Cat, Charcoal can etc). I have a vq30det ecu, but after several days of poking around with it, I couldn't get the damn thing working - there's hardly any documentation on it.
Another thought I had was running alcohol/water injection. I could then keep the aggressive timing which would make the car very nice and responsive. I could get a boost switch to activate it at around 5psi or so. Anyone else here running a setup similar to this?
You could do that. I and many others have used water and or methanol injection on VQs with good results.
Regards to reducing fuel pressure... I ran 28psi base fuel pressure with my 370cc injectors for 3 years, no problem.
You can run 8psi on stock VQ30DE timing even with the 10:1 pistons with a smallish turbo like the DET turbo, though that's as high as I'd go on US pump gas (92 or 93 octane). Any higher than that and I'd want to start retarding timing. Again not sure what your octane ratings there are like, and if they're measured the same way they are in the states.
__________________ 95 SE - Stock 3.0L w/ USIM - T61/P-trim @ 14.5psi - 93 octane
11.76 @ 121 - 1.82 60' - ET Street DOTs
12.15 @ 123 - 1.95 60' - Nitto DR 3.5L swap with I/Y/E
12.92 @ 104 - 1.69 60' - M&H Slicks
13.60 @ 103 - 2.15 60' - Street tires
If your in a budget, I think the cheapest route would be water/meth injection. I have been using the injection for 3 years and no issues. It will allow you to keep the stock aggressive timing of the VQ30DE ECU, while eliminating(reducing actually) the chance of knock. Buddy of mine here on the org was able to produce 395WHP on his 10:1 compression, stock timing VQ30DEK, with also 100% methanol injection and 93octane fuel.
I've also just learned about the Apexi Super ITC - which allows you to retard timing based on RPM. Sounds like it will also do the trick and because it's pretty old, I should be able to get a second hand one locally at a good price (hopefully)
I've also just learned about the Apexi Super ITC - which allows you to retard timing based on RPM. Sounds like it will also do the trick and because it's pretty old, I should be able to get a second hand one locally at a good price (hopefully)
The problem with retarding timing based on RPM is that, in first gear since you probably wont get the same boost level as higher gears. Its going to retard unnecessary timing. Unless you get full boost in 1st gear.
You don't want to retard timing based solely on RPM. You want to do it with boost or mass airflow. Partial throttle would be absolutely terrible. Fuel economy would be terrible. Not a good idea.
You probably won't be able to flow enough fuel at acceptable IDCs (perhaps not enough at all, period) if you put the stock 240cc injectors back in... you don't want to do that. Makes no sense. The point of bringing the FP back with your current 370s (which are actually 410cc injectors) is to bring that -17% correction back closer to zero.
__________________ 95 SE - Stock 3.0L w/ USIM - T61/P-trim @ 14.5psi - 93 octane
11.76 @ 121 - 1.82 60' - ET Street DOTs
12.15 @ 123 - 1.95 60' - Nitto DR 3.5L swap with I/Y/E
12.92 @ 104 - 1.69 60' - M&H Slicks
13.60 @ 103 - 2.15 60' - Street tires
But if you were to reduce the fuel pressure enough to have the SAFC set to 0, wouldn't it be flowing the exact same amount, just with worse atomization?
In regards to the ITC, I can see your point - but it would beat just reducing the base timing. Maybe I can rig it up so that it only operates when a boost switch is set on or so. The turbo spools up pretty fast being quite a small T3.
But if you were to reduce the fuel pressure enough to have the SAFC set to 0, wouldn't it be flowing the exact same amount, just with worse atomization?
In regards to the ITC, I can see your point - but it would beat just reducing the base timing. Maybe I can rig it up so that it only operates when a boost switch is set on or so. The turbo spools up pretty fast being quite a small T3.
Not sure you understand, by having the SAFC correcing -17 (for example!), indirectly you are increasing your ignition timing!, so since you dont want that. You reduce the fuel pressure, so less fuel is being sprayed, and therefore you dont have to remove so much corrections on the SAFC, therefore your not increasing timing. Get it?
But by reducing the pressure on the 370cc (to get 0 on the SAFC), you'd be flowing exactly the same as what a stock injector would be flowing and still have the same duty cycle limitations.
If you swap your current injectors for stock injectors you would have to run much higher fuel pressures and duty cycles to flow the same amount of fuel that your current injectors do. Neither of those are desirable.
__________________ 95 SE - Stock 3.0L w/ USIM - T61/P-trim @ 14.5psi - 93 octane
11.76 @ 121 - 1.82 60' - ET Street DOTs
12.15 @ 123 - 1.95 60' - Nitto DR 3.5L swap with I/Y/E
12.92 @ 104 - 1.69 60' - M&H Slicks
13.60 @ 103 - 2.15 60' - Street tires
But by reducing the pressure on the 370cc (to get 0 on the SAFC), you'd be flowing exactly the same as what a stock injector would be flowing and still have the same duty cycle limitations.
Like Neal said, you duty cycle will be higher, you dont want that. just listen to us lol. No sense in putting smaller injectors.
ignition timing is crucial in the performance of an engine.the ignition timing affects many variables including engine longevity, fuel economy, and engine power. modern engines that are controlled by an engine control unit use a computer to control the timing throughout the engine's rpm range.
ignition timing is crucial in the performance of an engine.the ignition timing affects many variables including engine longevity, fuel economy, and engine power. modern engines that are controlled by an engine control unit use a computer to control the timing throughout the engine's rpm range.
Really? you quoted Wikipedia with information we all already know or this discussion wouldn't even be going on.
I will donate the ecu & pay to get it in your hands.
Linear Mode
