sloth

Btw, it could be psychological, but the car does feel somewhat better (smoother ride). The workshop where I took the car first did take the shock apart and lube it, so perhaps this masked the extent of the wear a bit - perhaps I'm lucky the KYB guy even noticed the slightly bad return travel at all. Greg

Thanks - that looks useful. I've had the shock replaced now (at no cost), but as it turns out, it probably wasn't the cause of the symptoms I was noticing. (a very easily audible creaking sound) The reason they replaced the shock is that the return travel was a bit slow, but they don't think that was causing the creaking. The creaking was apparently caused by two things: a) the rubber spacer/bushing (for the top of the shock mount?) had been installed upside down, and B) the "top mounts" needed lubricating. (seems unlikely to me that two things would have gone wrong at the same time, but that's what they told me) Greg.

There's actually a whopping two years warranty on these KYB shocks - amazing. So I guess I'll just keep going back every 12 months when they fail to get a free replacement. :wassup: Greg.

I honestly don't know how I did it, except as I say, Sydney's roads really are *bad*. Both times it has been the left rear which has gone. (the original shocks were almost certainly the stock Nissan shocks, though, whatever they are) Greg.

Thanks. Yes, I have been reading some of the other posts, and Bilstein certainly does seem to have a good reputation here. (I nearly posted my question in one of the other recent threads, but I didn't notice any discussion about reliability, so I decided to start a new thread) Greg.

Hi, My KYB gas shocks on the rear of my R33 GTS-t lasted 12 months/25000km, and I need to replace them. The workshop is suggesting another pair of KYBs. I don't know exactly which type of KYB I have, but they're not adjustable. I only use the car for day to day street use. Should I consider a different type of KYB, or a different make entirely? I'm willing to pay more for something which will last longer on what seems to be increasingly poor Sydney roads. Thanks, Greg.

Powerdigger helped me find the MAP sensor - it's located behind the driver's side top suspension mount, just in front of the firewall. I can clearly see the hose going to the manifold. I can also see a seperate wire spliced in to the cable that runs in to the cabin - this must be the pressure signal for the EBC. (the Powerdigger Hybrid EBC has an open loop mode - I thought *perhaps* my EBC had been wired for open loop mode, but fortunately that's not the case, unless of course there's a fault in the cabling). If I do decide to monitor this boost signal, it's going to be fairly easy to access it. I'm probably not going to bother though, because it seems that the slight boost falloff I'm experiencing is probably entirely normal. Greg.

Ok, thanks for the info. I called a performance workshop and they too said that the standard turbo may have trouble flowing 10.5psi at high revs, although if the boost is set to, say, 15psi, it will drop to about 10psi at high revs - this agrees with your observsations. I certainly did not test the high boost to redline - as soon as I heard the engine splutter, I pulled back. (I didn't even know about fuel cut overboost protection when I did this little test - I thought I may have blown my engine and was very relieved. I had assumed that the workshop would probably have calibrated my EBC such that it was not possible to crank the boost up so high - boy was I wrong!) Greg. p.s I can't seem to figure out how to get the attachment to upload - sorry.

For what it's worth, here's my dyno plot - looks like I slightly exaggerated the boost dropoff - it only drops to about 9.5psi, not 8.5psi as I said earlier. Is this small dropoff normal/expected with my setup? (air filter is a K&N panel by the way) Greg.

Yes, it is the stock turbo, but I do have a dump & 3" exhaust. Thanks, Greg.

Ok, thanks. I do know that if I crank up the EBC's boost setting, the boost skyrockets (to the point of inducing a fuel cut), so if the problem is with the wastegate actuator, it must be a problem that only exhibits itself after being on boost for a relatively long time, because it is definitely strong enough for a short burst. Greg.

The EBC's solenoid fits in *series* with the pressure line to the wastegate actuator, right? (i.e, it's not a bleed type solenoid) This means that when the solenoid is in the closed position (blocking all pressure from reaching the wastegate actuator), the wastegate would have no pressure on it, and the boost would rise to whatever the wastegate would allow. Do you mean the actual wastegate actuator, or the wastegate itself? Greg.

Powerdigger are telling me the car *does* have a seperate boost sensor - i.e - seperate to the airflow meter. Now I'm confused! Greg.

I notice from the boost vs rpm plot I received from my dyno tune that the boost gradually falls off from about 10.5psi down to 8.5psi at redline. I am using the Powerdigger Hybrid EBC. This took me by surprise, because I've never noticed this falloff on the factory boost gauge. Is it correct that the factory ECU creates the boost level signal from the airflow meter signal? If so, could the falloff be due to a non linearity in the conversion of airflow to boost pressure? It just seems to me that the EBC might be doing it's job as best it can, using the boost level signal from the ECU, and that the only way to fix this would be to install a MAP sensor. (although I have no idea whether the Hybrid EBC could directly make use of a MAP sensor). Greg.

This is exactly what I have read elsewhere, but I'm not sure it's correct. When a lower gear is used, the dyno will be spinning slower, so the power will be proportionally less, cancelling out that increase in torque. This link is pretty good: http://www.superflow.com/support/cycledyn-theory.html What I said in an earlier reply about the mass of the dyno being tuned to be about right for 4th gear (or a particular vehicle speed range) is definitely wrong - according to that link the mass of the dyno actually simulates a particular vehicle weight, so if the weight is a good compromise, meaningful runs in *any* gear should be possible, although the acceleration rates won't match on-road rates exactly, even if the dyno mass produced an exact match to the vehicle weight, due to traction and drag etc, I guess. Anyway, next time I have a dyno done I'm going to ask them to do a quick run in 3rd gear. I bet the resulting power will be *less* than 4th gear, not more, because of the increased transmission losses in the lower gear. In 2nd gear, my AP22 accelerometer reports a maximum power at the wheels of 138kW, despite a very recent 4th gear dyno run reporting 168kW. Greg.

I think the original poster was referring to the weight of GTRs, which are of course heaver than the GTS-t's. (my R33 weighs 1400 +/- 20, with two thirds of a tank - about the same as yours) Greg.

RE: the drag with the XR6 Turbo - my brother's just bought an XR6 Turbo UTE and we measured 6.6 seconds 0-100 with an AP22 performance meter, with me in the passenger seat and a bit of other load as well. He revved it a bit with foot on brake, but it was rather gentle and no wheel spin at all. The best I've managed so far in my GTS25t is only 7.4 seconds on standard boost, but I don't launch *really* hard. (I certainly launch harder than he did, though). I reckon he's a lot faster than me, unfortunately. (I'm sure a skilled driver could do a lot better than me in my car - I accept that. Unless my car has a problem, but it's had a few dynos and the tuners reckon it's just fine) Greg.

Thanks! I'm *beginning* to understand this, I think. I read somewhere else that the frictional losses in the transmission are greater as the gear is lowered, and this is one reason they use 4th gear - it represents the truest measure of power at the wheels which the car is capable of. I did read elsewhere about the acceleration being greater in lower gears (e.g 3rd) - i.e - the dyno will spin up faster, giving a falsely high reading. This didn't make sense to me at first, because I thought that the dyno should still be able to measure the true power (and get the same result), because the dyno will be spinning slower in 3rd gear - i.e - the car is travelling slower over the (false) road. I think the problem is that we are trying to measure *dynamic* power, not static power. So, whatever gear we do decide to dyno in, the rate of rpm rise should represent what the car would actually experience when driving. For example, if we were to dyno a car on a standard dyno, in 1st gear, the load presented to the engine would be huge compared to what it would experience on road. So, the resulting power figure would not reflect the *dynamic* power which is available by using things like lightened flyhweels and smaller pulleys etc etc. Another issue I read about is the risk of wheel spin in lower gears. Up until now, I thought a chassis dyno was a very sophisticated thing, which actually tried to mimick the car being on the road. However, it seems that it's just a big heavy wheel, and thus, it's "tuned" for a fairly typical load in 4th gear. I think. Greg.

This is probably a dumb question, but why do they typically dyno a car in 4th gear? Will the maximum power be progressively less, the lower the gear, or does it stay about the same in each gear? Thanks, Greg.

Do any of the aftermarket dash replacements have a more readable boost guage? Re: the "7+" - yes, it's in units of 100mm Hg (mercury), so the +7 = 700mm Hg, which is equivalent to 13.5psi. Thanks, Greg.

I've heard that the factory boost gauge on the R33 GTS-t isn't very accurate. Is the innacuracy mainly due to the meter, or the boost sensor itself? If the boost sensor is accurate, I thought perhaps I could use a more accurate voltmeter to replace the meter on the dash, as an alternative to installing a pneumatic boost guage. Greg.

Thanks for the info everyone. My car is a '95 model but I haven't checked my ECU yet. I do recall the workshop being surprised at the power gain after installing a 3" turbo back, high-flow cat and pod filter - it went from 121kW up to 147kW, however they said the timing had to be pushed back a fair bit as well. (they said that it appeared to have been tuned for the Japanese fuel) I now have 168kW @10.5psi - nothing wrong with my maximum power, but it would be nice to have the nice linear power delivery that I remember seeing on the Series 2 dyno plot. I have an EBC which has helped to bring on the power earlier (by eliminating the two level boost staging which the factory boost controller produces), but it still doesn't look as linear as I remember the Series 2 being. Just for kicks, is anyone able to post a Series 2 (in stock form, or close to) dyno plot? Greg.

Hi, At a dyno day I noticed that a R33 Series II GTS25t produced a much more linear power curve than my Series I. A performance workshop has told me that this is entirely normal, and it's because the Series II ECU is superior. Is it reasonably easy to install a Series II ECU into a Series I? Thanks, Greg.