Jump to content
SAU Community

Recommended Posts

New battery sourced, thank @BK and @Dose Pipe Sutututu

On special at Autobarn too so win win...

The guy at Autobarn saw that I was replacing my Optima with this and said I was nuts going from an Optima to a Supercharge, haha

thumbnail_IMG_6028.jpg

thumbnail_IMG_6027.jpg

  • Like 1
  • 3 weeks later...

Ended up making 430rwkws on E85 at just 20 psi.

Having alternator issues (not the limiting factor I was expecting)..

Tuner says it's still got more in it with a new alternator so looking into the LS1 conversion...

...Not heaps though as the small rear wheel is just beginning to restrict things and potentially my small pod filter too....

8 hours ago, mr_rbman said:

Ended up making 430rwkws on E85 at just 20 psi.

Having alternator issues (not the limiting factor I was expecting)..

Tuner says it's still got more in it with a new alternator so looking into the LS1 conversion...

...Not heaps though as the small rear wheel is just beginning to restrict things and potentially my small pod filter too....

Alternator limiting how ? I smell bullshit...

Coils and fuel pumps are your most power hungry things and I'd expect dramas very early in the tuning process if this was the case from a alternator causing a low voltage condition.

On 2/2/2023 at 10:24 PM, BK said:

Alternator limiting how ? I smell bullshit...

Coils and fuel pumps are your most power hungry things and I'd expect dramas very early in the tuning process if this was the case from a alternator causing a low voltage condition.

mmmm, interesting...

This side of things (electrical) goes over my head so I just took him at his word...

I'll have a chat to him next week to get a clearer understanding...

if the alternator can’t keep up and the voltage drops then it slows the fuel pumps slow down and can’t supply their full potential along with a list of many other things it does to the tune 

Or he's getting misfires with more boost because the voltages are subpar and his coils aren't producing the required spark.

I've experienced this, hence I have a relatively new 90AMP Circuit Sports alternator in my car.

 

3 hours ago, r32-25t said:

if the alternator can’t keep up and the voltage drops then it slows the fuel pumps slow down and can’t supply their full potential along with a list of many other things it does to the tune 

Like I said, the low voltage condition from an alternator will mainly affect fuel pump and coil operation but it has to be pretty severe to do that, injectors draw stuff all by comparison. Coils would start misfiring and you would start to have low fuel pressure lean outs, but the fact it supported enough for well over 400kw with stable AFR and no jittery power curve from misfies uptop doesn't really point to coils misfiring or low fuel pressure from the alternator limiting things at all. My point is you will see something more sinister happening well before you get to tune the thing properly.

4 hours ago, mr_rbman said:

mmmm, interesting...

This side of things (electrical) goes over my head so I just took him at his word...

I'll have a chat to him next week to get a clearer understanding...

Now don't get me wrong, having a more capable alternator with more headroom is always a good thing. I myself went from the stock 90A to an ARD 140A as I could see I was  getting only 12v at battery with all 3 fuel pumps running at idle under test conditions and would cause dramas. The ARD jumped it back to about 14.3v at full load at around 70A. End of the day a better alternator is never a bad thing, just usually not a likely thing if everything else checks out.

1 hour ago, Dose Pipe Sutututu said:

Or he's getting misfires with more boost because the voltages are subpar and his coils aren't producing the required spark.

I've experienced this, hence I have a relatively new 90AMP Circuit Sports alternator in my car.

 

If this is the case you don't need to be at full load to see if something doesn't look right as your voltages even at idle will be a bit suspect.

1 hour ago, BK said:

this is the case you don't need to be at full load to see if something doesn't look right as your voltages even at idle will be a bit suspect.

Yes that is also true however it's not the first thing you look at when you're tuning.

Generally you'll interrogate voltages when things don't go as expected or planned, e.g. a misfire or sensors doing cooked shit lol

 

22 minutes ago, Dose Pipe Sutututu said:

Yes that is also true however it's not the first thing you look at when you're tuning.

Generally you'll interrogate voltages when things don't go as expected or planned, e.g. a misfire or sensors doing cooked shit lol

I get where you're coming from, but establishing the very important basics with things like what baseline voltages are at battery and fuel pump terminals, fuel pressure, base timing, spark plug type and gap and so on should be a given as a precheck before going anywhere near a dyno.

Going on a dyno to tune without doing any of this with something like say less than 13.0v at pump terminals or god forbid actually at the battery is just asking for tuners to crack the shits, as that will immediately flag potential problems elsewhere. i also accept unforseen things happen that can't be picked up until actually exposed on the dyno too, which is why the are such a great tool.

I notice a lot of places are asking for dyno prechecks to avoid exactly this sort of thing.

On 2/5/2023 at 5:30 PM, mr_rbman said:

so what should i do (from home) to eliminate other issues or potentially confirm that the alternator isn't up to the task?

Measure voltage at the battery, and voltage at the pump .

You can get multimeter that log over bluetooth pretty cheap from jaycar. Then you can see what us happening under load. 

 

I cant recall what ecu you are running, but it should be able to log its own voltage if it is any good.

1 hour ago, Ben C34 said:

Measure voltage at the battery, and voltage at the pump .

You can get multimeter that log over bluetooth pretty cheap from jaycar. Then you can see what us happening under load. 

 

I cant recall what ecu you are running, but it should be able to log its own voltage if it is any good.

cheers.

Link G4X so yes you're right, i'll plug the laptop in and have a squiz (not used to a car with logging capabilities 🙃

1 hour ago, mr_rbman said:

cheers.

Link G4X so yes you're right, i'll plug the laptop in and have a squiz (not used to a car with logging capabilities 🙃

Start a log, wind out second gear, stop log.

Then look at voltage vs. RPM and see what it's doing.

(This is my experience, may not apply to others) Voltage might be perfect at idle, but over a certain RPM it will fall flat on its face and do nothing then back to 13V+ towards redline. Hard to catch without proper logging.

  • Thanks 1

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

    • A lot of what you said there are fair observations and part of why I made that list, to make some of these things (like no advantage between the GSeries and GSeries II at PR2.4 in a lot of cases) however I'm not fully convinced by other comments.  One thing to bare in mind is that compressor flow maps are talking about MASS flow, in terms of the compressor side you shouldn't end up running more or less airflow vs another compressor map for the same advertised flow if all external environmental conditions are equivalent if the compressor efficiency is lower as that advertised mass flow takes that into consideration.   Once the intercooler becomes involved the in-plenum air temperature shouldn't be that different, either... the main thing that is likely to affect the end power is the final exhaust manifold pressure - which *WILL* go up when you run out of compressor efficiency when you run off the map earlier on the original G-Series versus G-Series II as you need to keep the gate shut to achieve similar airflow.    Also, how do you figure response based off surge line?  I've seen people claim that as an absolute fact before but am pretty sure I've seen compressors with worse surge lines actually "stand up" faster (and ironically be more likely to surge), I'm not super convinced - it's really a thing we won't easily be able to determine until people start using them.     There are some things on the maps that actually make me wonder if there is a chance that they may respond no worse... if not BETTER?!  which brings me to your next point... Why G2 have lower max rpm?  Really good question and I've been wondering about this too.  The maximum speed *AND* the compressor maps both look like what I'd normally expect if Garrett had extended the exducers out, but they claim the same inducer and exducer size for the whole range.   If you compare the speed lines between any G and G2 version the G2 speed lines support higher flow for the same compressor speed, kinda giving a pretty clear "better at pumping more air for the same speed" impression. Presumably the exducer includes any extended tip design instead of just the backplate, but nonetheless I'd love to see good pics/measurements of the G2 compressors as everything kinda points to something different about the exducer - specifically that it must be further out from the centerline, which means a lower rpm for the same max tip speed and often also results in higher pressure ratio efficiency, narrower maps, and often actually can result in better spool vs a smaller exducer for the same inducer size... no doubt partly due to the above phenomenon of needing less turbine speed to achieve the same airflow when using a smaller trim. Not sure if this is just camera angle or what, but this kinda looks interesting on the G35 990 compressor tips: Very interested to see what happens when people start testing these, and if we start getting more details about what's different.
    • I know right. It baffled me. There's no way when the engine is off, key is in ignition, (coils are dissconnected aswell), also my sound system was dissconnected (I don't run any audio capacitors), battery reads 12.2v and with the 10amp fuse blown I was measuring 24 to 30v. The reading would move a bit from 30v to 24v which was weird. I took a pic of the multi meter reading 🤣: (This is a brand new single channel digital oscilloscope that also has a multi meter mode).   Before when the fuse was blown, I had one lead on the 12v supply (green/white wires) of that brown relay and the other lead on the negative battery terminal. When I turned the key on ignition (engine off), it would read 30v. Then when I removed that relay from it's plug and tried putting ignition on again, it would read 12v, but I think it's because it can't turn on the ecu now that I removed it. I asked Chatgpt and this is what it had to say:   Not sure if those theories would be possible but, any auto sparkies here? welcome to confirm. 🤷‍♂️  No idea, but if it happens again, atleast I know what type of issue it is, unlike last few months where I didn't know what was causing all my issues and I was just taking stabs in the dark to figure out what type of problem it was. If it does happen again I'm going to investigate futher and trace back the source even more and inspect more circuits. I drove it to work this morning and the car drove and boosted fine. Yeah I was thinking the same, so I've imported my back up saved map (which is the map that I saved when it got done tuning) back onto my haltech with the base fuel pressure set to 43.5psi.
    • Yeh nice, if your in melbourne could you recommend any exhaust shops in the east that do a good job?
    • Sorry yes, this is what im after Also, that jpjdm site appears to be offline
×
×
  • Create New...