Sydneykid

Gas (nitrogen) under pressure (45 psi or so) is used to reduce the foaming of the hydraulic fluid as it passes through the valves. Air bubbles are bad for damping consistency as they whip through the valves much easier/faster than the fluid and so give zero damping. Most shocks these days are gas pressure, pretty much only the vintage shocks are not. cheers

Try the Group Buy; http://www.skylinesaustralia.com/forums/in...showtopic=87521 cheers

Check out the thread on the differences between a bad shock and a good shock for more information. http://www.skylinesaustralia.com/forums/in...howtopic=114718 cheers

Check out the thread on the differences between a bad shock and a good shock for more information. http://www.skylinesaustralia.com/forums/in...howtopic=114718 cheers

Check out the thread on the differences between a bad shock and a good shock for more information. http://www.skylinesaustralia.com/forums/in...howtopic=114718 cheers

If your car has ABS and the current brakes can activate it, then changing callipers, rotors or pads is a waste of money. The weak link in the stopping distance is tyres, buy the best tyres you can find. When you can longer activate the ABS, then it's time to upgrade the brakes. cheers

Nope, do a search and you will find out why. cheers

For some time lot's of guys have been asking me to explain the differences between a good shock and a bad one, what sophisticated valving really means, why a monotube shock is better than a twin tube etc etc. So this thread is an attempt to answer those questions and any others that might come up in the process. To kick it off I thought I would start with why a monotube shock is better than a twin tube. Monotube shocks have a larger piston area than a twin tube for the same given outside diameter. This larger piston OD/monotube design means that; 1. There is room for more valves 2. The valves themselves can be bigger 3. More hydraulic fluid is moved for the same stroke, this means superior metering of the fluid transfer though the piston. 4. There is more fluid in the shock, which means higher temperature capacity. The movement of the fluid through the valves generates heat (Newtons law at work) by transforming the kinetic (up and down) energy. 5. The fluid is in direct contact with the shock body meaning rapid transfer of heat to the outside )ambient) atmosphere. Following is a shock dyno graph (courtesy of Bilstein) showing the effect of heat on dampening of a typical Japanese twin tube shock. As you can see after 2 minutes, yes that's 2 minutes, of running at 550 mm/sec the damping force (the vertical axis) drops off dramatically. For those that haven't seen a shock dyno graph before the vertical axis is the damping force and the horizontal axis is the speed (frequency) of the up and down. This means is the damping efficiency of shock drops away due to the rapid overheating of the fluid. Because of the twin tube design there is insufficient fluid to absorb the heat and the two tubes slow down the heat transfer to outside atmosphere. What you feel in real life is a gradual decrease in damping effect, the shock slowly ceases to control the spring and the chassis. You get move vertical/roll movement, the shock no longer helps to keep the tyre in contact with the road. Hope that was in some way informative, the next subject (with pictures) will be a comparison of the design of the shock piston and the valve pack. Cheers

All true Roy, no arguments from me. But I should point out a few things; 1. We have had several Skylines with similar K's, this one showed excessive wear in the components mentioned in comparison to the others. This was the one with super low springs and standard shocks. 2. The worn components are what I expect from a excessively low Skyline with inadequate shock damping. What is adequate bump damping at 370 mm is not adequate at 315 mm. What is adequate rebound damping for a 165 lbs per inch spring rate is not going to do the job on a 235 lbs per inch spring. 3. Note the height at 315 mm, using springs specified at 335 mm. That's a common sign of spring steel fatigue caused by inadequate damping. 4. A new standard shock is not going to have as much problem with lower/higher rate springs than one that is 70,000 k's old. Most suspension people will tell you standard Skyline shocks are well worn at that sort of k's, you can see it on the shock dyno. Sure this is an extreme example of what happens, but it is far from unique, I used to see at least one car a week with this sort of damage when I was dealing with the public. The guys were willing to spend $900 on an intercooler in an instant, but $900 on shocks was another matter. cheers

Yep, I have the actual numbers somewhere. The R34GTT intercooler was around 68% efficient for cooling at ~200 rwkw. That compares pretty favourably with a standard R32GTR intercooler on the same engine which was 72% efficient at similar power levels. At 200 rwkw and 7,250 rpm, the R34GTT intercooler (and pipework) had 1.5 psi restriction at 1.3 bar. The R32GTR intercooler, with larger pipework and similar power, was 0.75 psi. So even the airflow wasn't too bad. That's why I am using an R34GTT SMIC on the Stagea, I know it won't have any problems with 200 4wkw. cheers

Since we race a Production R32GTR N1 spec and an Improved Production R32GTR I guess I can comment on the differences; Group N cars aren't allowed to change their stabiliser bars, so they have to run high spring rates front and rear to compensate. Group N cars aren't allowed to change their anti dive, so they have to run high front spring rates to compensate. Group N cars aren't allowed to change their anti squat, so they have to run high rear spring rates to compensate. Group N cars aren't allowed to change their caster, so they have to run high front spring rates to control the roll enough for the camber to compensate. Group N cars are allowed to run full slick racing tyres, which will tolerate a much higher spring rate than a road radial or even an "R" tyre. Lastly, shock absorber technology has moved a long way since 1989 and we simply don't have to run the high spring rates now that we did then. Hope that answered the question. cheers PS; The tracks in the UK are a lot smoother than what we have locally.

GTR's are around 200 kgs heavier that GTST's of the same model and most of that weight is on the front wheels. The same front spring rate makes no sense in that regard. cheers PS; check out the Group buy thread for Whiteline springs http://www.skylinesaustralia.com/forums/in...showtopic=85467

Here's your problem, with 2530 's on a 3 litre you will hit boost at freeway running speed in 5th gear. That means just a gentle roll onto the throttle at 100 kph will generate plenty of boost. This absolutely kills the fuel economy and actually makes the car hard to drive smoothly. You just want to hold the speed up a slight hill or accelerate gently and bingo it's boost time and away you go. I found it hardly ever ran closed loop and guzzled gas like crazy. Much better to pick a turbo/turbos sizing that doesn't boost up until 3,000 rpm or so, that works much better for the 100/100 kph speed limits. Don't confuse response with boost build, you can still get good throttle response from a 3 litre with turbos that don't make boost until after 3,000 rpm. It's all in how you tune it. cheers

Open to atmosphere BOV's don't work very well with AFM's as the main load sensor. Achieving a consistent and stable return to idle takes lots of tuning, road tuning, you can't duplicate it very easily on the dyno. My recommendation (as always) is to use the standard plumb back BOVs on a GTR. The problem is very simple, the open to atmosphere BOV's dump a whole lot of air, air that the AFM's have already measured as going into the engine. So the ECU squirts in enough fuel for that amount of air, too much fuel = rich running just as the engine is try to achieve a stable idle. Hence the stalling. The easiest/cheapest answer is to keep that air within the system, not dump it outside. Why you think it worked OK for a while and not now is beyond me. Maybe you are driving it more agressively than you were when you first got it. Snapping off the pedal after a wide open throttle, rather than rolling off progressively. cheers

I have used an R34GTT SMIC on an R32GTST and it made 205 rwkw, no problems, all day, everyday. It's an easy and cheap mod and I was very happy with double the standard power. TargaTas did the same and he achieved ~220 rwkw (his engine was fresh). We get very glib on SAU about 200 rwkw not being enough, and you not trying if you don't have at least 400 rwkw. Well 200 rwkw is plenty enough for lots of people and it makes an R32GTST pretty damn fast. So I have this opinion that if the guy wants 200 rwkw then we should help him how to get there for the least cost. Not tell him he should be aiming for 300 rwkw. So to answer the question on how ottfit an R34GTT intercooler to an R32GTST, you have two choices; 1. Modify the intercooler pipework in the engine bay (as per page 1 of this thread) so that it fits up to the R34GTT intercooler rear outlet. 2. Cut off (from the rear) and reweld (onto the front) the pipework on the R34GTT intercooler outlet tank. All I did was take my R32GTST intercooler and the R34GTT intercooler along to my local aluminium welder (in the yellow pages). I told him I want this (the R34GTT intercooler) to have the outlet on the rear just like this (the R32GTST intercooler). Cost me $50 and he did it while I waited. Hope that was of some help cheers

Are they plumbed back or open to atmosphere? cheers D: PS, the standard GTR BOV's are far better than almost every aftermarket BOV you can buy.

We use Microtechs on the rotary race cars, wouldn't use anything else. But NEVER on an RB26, multiple throttle bodies on a turbo charged engine are not their game. Notice how all the favourable reports from Microtechs on piston engines talk about max power with single throtte bodies. No mention of piss poor closed loop running, wasted spark ignition, difficulty driving individual cylinder CDI, installation time and cost, idle speed control via AAC for electric load, power steering and airconditioning, inacurate base maps etc etc They simply can not compete on a value for money basis with a $960 buy and $300 tune Power FC. Cheers

On the R34GTT we started to run into problems around 245 rwkw. Boost was irrelevant, it's all about the airflow through the tube. How much resistance to airflow (boost) there is after the turbo has no effect whatsoever. Cheersw

Suggestions to your questions follow; 1. Yes, more caster improves steering feel, as well as reducing the tendancy to wander at speed and improving the turn in. Note that the caster kit bushes not only improve static caster but the further improve the dynamic caster as they resist deformation under load. 2. No, the rear subframe alignment kit actually reduces the stress on the standard bushes. They absorb a hreat dea lof the loadings that would other have ot be absorbed by the standard rubber (silicone filled) bushes. 3. Stabiliser bars reduce the roll, that's their job. They do add a little to the bump stiffness, but more than 50% less than would be the case if the roll was reduced the same amount by using stiffer springs. A stabiliser bar connects to both wheels on the same axle. Which means for a given amount of roll 50% is on the outside wheel (in the corner) and 50% on the inside wheel. For a spring to stop the roll it only works on the outside wheel. In fact the higher spring rate pushing upwards on the inside wheel actually increases the roll. Stabiliser bars are the best bang for buck suspension upgrade you can make. Hope that answered your questions cheers

Impossible to answer without knowing the power target and what the car is going to be used for. cheers D

Bump is compression of the shock, rebound is extension of the shock. cheers

I have a set of stuffed Teins that I am in processes of dissassembling, in my spare time (there ain't much of that). I will then post up some pictures of the Bilstein valving compared to the Tein valving. The only problem I see with doing this is once I have done Teins people will ask for KYB, or Jic or ............ In the interim; The number of valves is important, there are shocks with 3 valves One for rebound, to dampen the spring oscillation One for bump, to dampen the compression, help the spring absorb the bump One for gross dump (to prevent shaft damage (bending) when a large bump/hole is encountered. These would be considered unsophistated compared to shocks with 5 valves; One for low frequency rebound, to dampen the spring return after hitting a bump One for high frequency rebound, to dampen the spring rebound after hitting a ripple in the road One for low frequency bump, to help the spring absorb the bump One for high frequency bump, to dampen the chassis motion on a ripply road One for gross dump (to prevent shaft damage (bending) when a large bump/hole is encountered. There are shocks with 8 valves, oneextra bump and two extra rebound. The size of the valves is important, there are shocks with valves as small as 1.5 mm, they can't fit larger valves because of the restrictions caused by the piston diameter. Obviously for the same given OD, a twin tube shock will have a smaller piston diameter than a monotube shock. The type and size of spring used to control the valve is important. The less sophisticated shocks use bevel washers as springs, as they are cheap compared to torsion bars or coil springs. cheers

Caster change angle, only on the front, causes feathering of the outside edge where the tread blocks are loaded. Doesn't do it on the inside of the tyre because it has negative camber to offset the positive caster. cheers

We have been running Optimax Extreme in the R33GTST for months. I have removed the filter twice and cut it open to see if there is any hose or pump damage and it was perfectly clean everytime. I have also removed cleaned and flow tested the injectors and they are exaclty as they should be. So the urban myth that 5% ethanol corrodes rubber hoses is 100% BS. So the urban myth that 5% ethanol corrodes fuel pumps is 100% BS. So the urban myth that 5% ethanol destroys fuel injectors is 100% BS. The R33GTST currently has a Power FC running the default maps, which usually means knock over 60 frequently. With Optimax Extreme in it we rarely see knock over 10, the peak was 25 one cold night. Based on the amount of ingition timing retard we have had to use to get the knock below 30 using 98 ron (ANY 98 ron) that is worth 12 rwkw. Don't get sucked into the ethanol is bad, that may apply to 20% or higher proportions. But 5% is NOT the same story. So I see no downsides to using Optimax Extreme and I am not the only one. Check around and you will find plenty of guys using it. cheers

Based on my experience, having to use 2nd gear on the dyno in an auto always makes the boost look spikey. You really need to use engine rpm instead of road speed when dynoing an auto. That at least removes the torque converter slip from the equation. The same set up in a manual in 4th gear would give a 1 psi spike which no one would be concerned about. My suggestions would be; 1. Turn up the boost, that turbo has plenty left in it. Around 22 psi is more like it. You have the bottom end to use it. 2. If you are still getting a 3 psi boost spike at 22 psi I would be looking for another boost controller. We use the PFC Boost Control Kit with plenty of success. 3. A set of 256 Tomei Poncams would be next on my list. An adjustable exhaust camshaft pulley is not necessary, based on our experience the Poncams are timed perfectly out of the box. That and the extra boost should see you comfortably over 300 rwkw. Cheers