Jump to content
SAU Community

Recommended Posts

Hey guys just looking for some opinions here, this is my last dyno run, on stock turbo (as far as i know) high flow'd fuel pump, front mount cooler, and 3" turbo back exhaust. boost at 12 psi however it drops of to around 10psi.

I know guys running the same mods and making 30kw less. my ecu has a "ksp tunning factory" sticker on it, could that explain it? do you think the turbo may be flow'd?

also what do you think I should expect from a safc?

Cheers

Russ

post-30174-1186585930_thumb.jpg

Edited by RPR33
Link to comment
https://www.sau.com.au/forums/topic/180112-what-do-you-think/
Share on other sites

I would expect no increase in power really as you can tell the dyno is a bit high with the AFR's like that which should be hurting it a little.

The power reading isnt high enough to suggest a larger turbo, just a minorly *high* reading to me on a stock turbo with a Jap modded ECU.

The ECU you have is probably fiddled with, but it doesnt really help here in AUS with our fuel and conditions.

So around 190-20rwkw genuine with the AFR's in the 12s once you get the S-AFC on there.

Pretty much what everyone else makes really

You should feel the difference with the AFR's a bit better. It wont feel as "doughy" so to speak. Bit more zippy on boost.

dont really know what im talking about but i got basically the same mods except my ecu hasnt been played with....

my A/F slope downwards tho, start at 12 and then head downwards.....might be able to post dyno graph later....

made 205kw so not uncommon....

but my A/F is definitely diff to yours....

I have had other dyno runs resulting in 218rwkw before. this is the lowest I have run on that boost (12psi) I put this one in because on that dyno on that day every else who run there car thought it was spot on... most people did get a little less then they had got on other dyno's. thats why I think it may be a flow'd turbo? with boost dropping to 10psi and a bad tune it's still making good power. I have mates running the same mods + safc and making the same power, however there boost will stay at 12psi, and there tune is alot better. and side by side I'd say my car has the power ot there's for sure!

also I have same what of a cold air intake. (boxed off pod)

Edited by RPR33

Definately looks a bit wierd from my experiences on the dyno. I have basically the same mods but with an safc and made 195rwkw on 10.5psi. But your afr's plummet to 10.5 in the main power band area so to speak which doesn't seem to affect your power curve. No dips no nothin... Seems weird to me. When my afr's we dropping that low before the safc i only had like 170rwkw or so with a real unsteady curve... could your timing be real advanced or something with the jap tuned ecu?

Yeh I think the timing would have been changed.. as you said it has a very good power curve and output considering the tune, thats why I think it must have something I don't know about??? any idea's guys???

Take a look at the bottom of the graph, it shows ambient temp as 22 degrees, and inlet temps as 40 degrees
Because his Intake temps are 18degrees above ambient temp.

Might see just over 200rwkw with the afr's cleaned up imo.

Nah, thats because according to Dyno Dynamics handbook, the sensor must be placed in the engine bay.

Which IMO is stupid as it adds a correction factor, and then the I/C does the cooling job so the air is no longer at same temp as the corrections being applied.

Hence a higher reading generally speaking.

Nah, thats because according to Dyno Dynamics handbook, the sensor must be placed in the engine bay.

Which IMO is stupid as it adds a correction factor, and then the I/C does the cooling job so the air is no longer at same temp as the corrections being applied.

Hence a higher reading generally speaking.

I agree its stupid, i used to stick it in the airbox/pod, but i agree, it should use the ambient as the correction, and the IT just for dataloging. And yes, it makes quite a lot of correction, by moving the sensor you can lose or gain 20rwkw at these power levels, that would explain the slightly raised power.

The temp correction is good for around 10-12rwkw if you have a 20 degree difference in temp. The pod isn't far from the radiator so the IT will creep up over time if the sensor is left there for a few runs. Best to just put it in there right before commencing a run.

The other thing worth noting here is your aftermarket ecu isn't doing too bad a job IMHO. Your mixtures are a bit rich but they are stable, and i suspect that the ecu is probably a little more aggressive with the timing than stock (as most of these remaps are) which means despite the rich mixtures you probably have a fairly nice responsive engine, where as a stock ecu with similar mixtures will be a bit of a slug as it will lack the timing.

I really don't think you'll gain a lot with an safc, as if you start to take fuel out i suspect you will run into detonation issues pretty quickly, but, i'm making an educated guess, so don't take that as gospel.

Why do you think I'll run into detonation issues? yeh I'd say the timing has been tuned up as It does drive very well! I hope I'll gain a little more power and at least get a little better fuel economy with a safc, as Its the worst skyline I've ever seen on fuel... I checked the fuel pressure today which I think is right at 40psi just switched on, and then upto 47psi once loaded up??

Nah, thats because according to Dyno Dynamics handbook, the sensor must be placed in the engine bay.

Which IMO is stupid as it adds a correction factor, and then the I/C does the cooling job so the air is no longer at same temp as the corrections being applied.

Hence a higher reading generally speaking.

Exactly..

so basically, if he had a CAI in this instance, it would have shown a lower amb reading and therefore would have had an even lower power output.

Why do you think I'll run into detonation issues? yeh I'd say the timing has been tuned up as It does drive very well! I hope I'll gain a little more power and at least get a little better fuel economy with a safc, as Its the worst skyline I've ever seen on fuel... I checked the fuel pressure today which I think is right at 40psi just switched on, and then upto 47psi once loaded up??

It's due to the way an safc works. by bending the afm voltage the ecu sees, it figures you are at a lower load point than you really are, which mean 1) less fuel and 2) more timing. So setting up an safc is a balancing act between getting correct a/f ratios and avoiding pinging.

Your base fuel pressure is a bit high. You should have ~36psi base (2.5 bar) with the vacuum signal to the reg disconnected. Plus boost, minus vacuum

Your fuel economy is likely due to a dead or disconnected O2 sensor.

yeh I have been told its not the o2 sensor,(in saying that I don't know if they have ever checked it). as soon as the car got bad on fuel that was my first thought but the machanics keep saying its just the computer... I guess it's just an easy way out without doing anything.

I had about 40 and then 47 with the vaccum to the reg disconnected??

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

    • I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
    • You don't have an R34 service manual for the body do you? Have found plenty for the engine and drivetrain but nothing else
×
×
  • Create New...