Jump to content
SAU Community

Recommended Posts

Hey Guys,

I've been looking around for the answer to my question with no luck, so make someone can help me.

I have an rb20det with 2530 turbs, gtr pump, adj cam gears, pfc, uprated injectors, exhaust and fmic, i'm just about to have the pfc tuned, but i'm not sure if i should change the AFM to a Z32? When does the stock one reach it limits??? Should i not bother with the z32?? I would say the car would be putting out 190rwkw once tuned.

Thanks in advance

George

Link to comment
https://www.sau.com.au/forums/topic/65010-upgrading-afm-on-rb20det/
Share on other sites

Its probably a worthwhile upgrade doing the pipe from the filter to turbo, it seems to have merit.

But if the pipe is sucking shut, then in theory that means there must be a measurable pressure drop accross the filter which may be worth looking at.

Think of it this way, imagine air being sucked through an open ended 3" pipe, its never going to callapse is it. Now imagine putting something over the end of the pipe, there may now be a tendency for the pipe to want to collapse due to the negative pressure.

So equate that to your air filter...if its wanting to suck close then there is a measurable restriction somewhere before your turbo:)

Its probably a worthwhile upgrade doing the pipe from the filter to turbo, it seems to have merit.

But if the pipe is sucking shut, then in theory that means there must be a measurable pressure drop accross the filter which may be worth looking at.

Think of it this way, imagine air being sucked through an open ended 3" pipe, its never going to callapse is it. Now imagine putting something over the end of the pipe, there may now be a tendency for the pipe to want to collapse due to the negative pressure.

So equate that to your air filter...if its wanting to suck close then there is a measurable restriction somewhere before your turbo:)

All true, but the inlet pipe itself is a restriction, I have seen one sucked in without any air filter at all. The convolutions, particularly around the bends are the main culprit. Since air flow is laminar (sticks to the outsides) having a smooth sided mandrel bend will reduce that restriction. As the rubber ages it gets softer where it flexes (when the motor twists on its mounts) and is more easily sucked closed. It shouldn't be high on your list of mods, but worth keeping in mind nonetheless. :D

Hey there, I have similar mods and just had my PFC tuned. My car got 172rwkw and my tuner said AFM was restricting things abit as it runs out of puff at 6250rpm.

It made sense to me with much more demand than standard and could see dip on curve, but I guess after reading here am I getting spun a load of crap or not??

thanks

i remeber martin donnon in HPI had a acticle about AFM, and he said it's only worthwhile to change the RB afm to Z32 once over 250rwkw
Hey there, I have similar mods and just had my PFC tuned.  My car got 172rwkw and my tuner said AFM was restricting things abit as it runs out of puff at 6250rpm.

It made sense to me with much more demand than standard and could see dip on curve, but I guess after reading here am I getting spun a load of crap or not??

thanks

At 172 rwkw it's not a problem, at 80 mm diameter, it's prettty much bigger than all of the pipework. There are plenty of other cars with AFM restrictions, but not Skylines.:D

Hey Guys,

I've been looking around for the answer to my question with no luck, so make someone can help me.

I have an rb20det with 2530 turbs, gtr pump, adj cam gears, pfc, uprated injectors, exhaust and fmic, i'm just about to have the pfc tuned, but i'm not sure if i should change the AFM to a Z32? When does the stock one reach it limits??? Should i not bother with the z32?? I would say the car would be putting out 190rwkw once tuned.

Thanks in advance

George

Hey george, i think u should be hoping for a little more than 190rwkw. Bbenny made about 220-230rwkw with the standard injectors and that turbo(hks2530) and a remapped ecu. So ulness u are only going to be running 1bar or so i think your estimate could be a little low. What does everyone else think, bbenny are you still around?

Be great to see your results and dyno graph posted george once the pfc is tuned. Oh and btw bbenny made this number with the standard AFM too :D

Us RB20 punters have to be careful when looking at dyno results. A 20rwkw difference is huge between 210 and 190rwkws, but from what i have seen can be easily accounted for by different dynos.

Inlet pipe sucking closed with no filter:( they are a horrible looking bit of pipe.

I suppose the point i was trying to make was dont go throwing a nice alloy pipe at it if you have a horrible filter restricing flow which may have been contributing to the problem. Fixing a problem is not always fixing the cause...or it may be that i like to complicate things:)

Thanks for the help guys.

i'm not interested in top end much, i want the most responsive internal stock rb20. that was the exact same request i made to jim at CRD. I'll keep ya posted how it goes.

Also i did a compression test today, i had driven the car but it then started raining really hard and had to stop for an hour or so and the car cooled down. The results i got were 130psi on 5 cylinders and 128psi on the 6th. Are these results good, bad, ungly????? or because it was cooled down these aren't accurate?

Cheers

George

hey,

i've got my pfc in now and taken the car for a light run...i'm finding the afm to reaching 4.9V on stock 32 actuator boost(2530 turbo) on a hot day. Am i gonna have trouble with this when i up the boost and have it tuned and have it out on a cold night?....i'm sure the car isnt putting down any great numbers at the moment...should i take the risk and take it to the tuner with the stock afm?

any suggestions would be appreciated.

Cheers

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...