dwhe009

anyone?

looks like my t3/to4e measure the smallest diameter of the turbine wheel and the compressor wheel and tell us

ok, so it is counting volume per cycle of the motor then. i would be interested in how exactly it does this, how the thing counts air? I am correct in saying most guys with rb20dets with stock ecu and injectors hit the fuel cut ( afm max) before the injectors run out? does this a safe way to find the limit of my set up would be to slowly turn the boost up until i hit the fuel cut, then turn it back slightly?

cheers rb-30 power. I have always wanted to know, is the air flow meter value a value of the volume of air coming in per time (eg second) or the amount of air coming in per cycle of the motor? Because if you have load (afm) versus rpm maps, then doesn't that mean you have load per cycle of the engine. eg the afm signal may say 2volts at 3000rpm at -2psi pressure and then 4volts at 3000rpm at +7psi boost and still say 4volts at 7psi at 6000rpm? am i correct?

anybody? will a fuel cut defencer help me get the little bit more? does it do this by holding the airflow meter signal just below its maximum? won't this make the ecu count less air than is actually coming in and therefore not give it enough fuel?

what is max voltage out of the standard air flow meter? is it 5.12v? what about injector duty cycle? how many milliseconds? I have made up the interface and i use conzult (the free version, for 300zx) to monitor these values. Anyone know of any other good free software that will data log so i can look through a run instead of nearly crashing as i try to look at data real time. ha ha

gidday, i have a rb20det with a few mods and i want to know how much further i can turn the boost up before either the air flow cut, or injectors max out. My mods, silver top rb20det t3/to4e turbo, 49mm turbine, 51mm compressor (73mm outside) 3" mandrel all the way through 400 by 600 by 70mm custom intercooler pod filter 0.8mm gapped plugs stock ecu The ecu has vs data rom on it. i assume this is some japanese tuner, I have had to turn the timing down to around 12 degrees before top dead at idle to make it not ping on boost. ( this maybe cos the chip was for good fuel?, i run 96) any ideas to get a bit more out of the car? It currently runs about 11psi. cheers

Dont use a auto ecu on a manual! I am presently having all sorts of problems with this. Maps are different, runs leaner on boost etc.

As for restriction, it is usually the intercooler that causes a pressure drop. Most guys with the norm, 2.25-2.5 inch piping+ say 300*500*50mm intercooler will only see around 1psi drop at 15psi. big deal.

If its mandrel bent, then it will work perfectly. 60mm is just over 2 and a quarter OD. This size is used by alot of intercooler kits. Some others use 2 and a half (63.5mm), this is only a 24% increase in cross section. Guys use 2 and a half inch for up to 400kw easy. It will easy flow well. Another point, if your total lenght of intercooler piping is around 4m (mine is), times this by cross section and you get volume of air in piping (4*pi*(.03)^2)=.011309m^3. Now a 2ltr motor uses 2ltr of air per 4 revolutions, or 2000ltr (2m^3) per minute at atmosphere pressure. at 15psi @ 4000rpm = 4m^3 per minute=0.0666m^3 per second. So now a 2ltr motor at 4000rpm @15psi will be swallowing .0666m^3 per second, so to fill your intercooler piping (one aspect of lag) will take .16 of a second. ha. crap all. if you do these calulations for 3" pipe it is quite similar (.26sec). You will find that most lag is the turbo having to spin up although you can feel that fraction of a second if anyone has run a motor without any intercooler at all. (these calcs did not include filling the intercooler up with air, (another .2sec approx) The 60mm piping will be exactly what you want.

this is a dyno run of a R33 with a manual conversion still running the auto ecu, quite funny. Does anyone know if this happens to R32's?

I was searching through threads and i found that when rb's with 5spd manuals are run by automatic stock computers the ratio's are leaner than with manual computers? Apparently there is large power loses due to this and timing changes when the auto computer thinks its changing gears. Has anyone experienced this/ heard of this?

how can i tell the ecu that it is in drive? When a conversion is done, do most guys swap the computers?

its about 10,000 times easier with oil pressure. As ylwgtr2 says, when there is oil pressure there is no contact between the bronze bearing and the housing, and no contact between the shaft and the bearing. I have one in my fingers right now. Pull it apart very carefully for yourself, thats the best way to learn about things. Make sure you have clean hands and clean everything with petrol, then add oil when you put it back together.

do you think i should get the ecu swapped at a wreckers then? how would i tell if my computer is an auto one? dont they both have the same pinouts? i had to input 10V into the automatic input pin to stop diagnostics code 54 coming up.

im still having problems getting my rb20det working well. I think my computer is a automatic computer and i have a maual box. When i installed the engine i hooked everything up, neutral switch etc, but i was wondering if this computer will still not work as well as if i had a manual one. can anyone confirm what computer this is, on side of box; 2371M 94L10 MEC-R113R 4921 Has anyone heard of the auto computer thinking its in park and therefore not running the right mixtures when on boost?

predator, I have a 600*400*80mm front mount, standard turbo, yes i know but im just playing till i find a rb25 turbo. I did a search and rang around and the fuel pressuse is supposed 2 be 45psi +/- boost, ie 37.5psi at idle, and should be 60psi at 15psi boost. I can clearly see it rise to 60, then fall off to 50 at the higher revs. In goes another pump, yay.

tomj, yeah sure, love pulling motors in and out and pulling them apart. I have a snatch block hanging from my garage all year round. still, it does not beat sex, i don't have a wank over cars like some do. Can anyone verify that my fuel pressure is too low (50psi) at 15psi boost? cheers

Cubes, am i right about the fuel pressure values? If so then i will clean out all the lines and injectors, then put in another pump in paralell to the VL one i already have. That should stop it leaning out.

to everybody who says put it on dyno, I know this would be the best way to slove the problem but im the kind of guy that loves to solve problems myself and not just watch someone else do it. I would rather blow up the motor than have someone fix everything and not knowing exactly what was happening and what he did. The most fun about having a quick car is playing with it. Thanks for all your help though

3LIT3 FORS3, Cheers for your great help BHDave, Are you sure about this fuel pressure, in the manual it says 2.5bar (37.5psi) at idle, and 3bar (45psi) with vaccum line on regulator off. ( i.e. 45psi base +/- manifold pressure) therefore at about 15psi boost, fuel pressure should be 45+15=60psi ?not 50psi? Cubes, cheers mate. Its just funny cos everyone goes on about the standard computer just going real rich at higher boost and i would be happy with that cos all i want is it to run safely at 14-15psi.

ok, heres a update on my problem. have been driving up and down motorway at 14psi today. Had a multimeter hooked up to air flow meter output. It showed correct values of 1V at idle and 1.5V at 2500rpm with no load. Was doing runs in 3rd gear from about 80kms and the cut only happened once. The air flow meter voltage goes right up to 4.8V at full throttle at around 5000rpm, but the fuel is not looking to good. I am seeing 50psi fuel pressure here and not good 14:1 ratios ( keep in mind i only have a jarcar meter hooked up to standard oxy sensor, not very accurate) . This must be leaning out due to fuel pump running out? It was starting to ping...... Am i right in saying the fuel pressure should be 45psi + boost (15psi)= 60psi?

cubes, the air flow meter has the oringinal mesh. Why, what does this do by removing it. It is definately the oringinal turbo. The Alchemist, I will try to watch the signal from airflow meter today. Cant use my oscilliscope cos it runs on 240V, ha. I hope multi meter will be fast enough to see what is happening.

i cant be my fuel pump as i can see it still holds 60psi while on boost. fuel ratios good. im quite a poor bugger so i might look at replacing the airflow meter if this is the problem, ( i cant afford z32+ retune) although, it must have something to do with the knock sensors as the cut does not appen at 14psi, with the timing turned right down. ( wouldnt this be same airflow?) i.e. @ 14psi, cuts with normal timing, @ 14psi does not cut with very retarded timing. The same airflow is going through the motor, its just firing at different times. Does this not eliminate air flow meter problem?

3LIT3 FORS3, how can a r32 have a boost cut, it has no map sensor. Cant it only have a airflow cut? If a coil pack was dodgy, then one cylinder would just miss, not cut. wouldn't it? When you say 90% of all R32 sylines have error 34 come up, this is bull, that would mean 90 % of all r32s are running like crap. any error code makes the engine run with much less timing and richer fuel. Plus this error code has only been happening since i upped the boost over 11psi.