Sydneykid

Looking at it another way, what if a 400 rwkw 4 speed auto was faster than a 500 rwkw manual? I guess it depends on what the target is, a faster time or more power? Personally, I would much rather brag about having doing a faster time with 400 rwkw.

I have seen around 20 damaged GTR gearboxes, leave out the poorly maintained ones (no oil changes or low oil levels) and the busted synchro ones. What is left have stripped 3rd or 4th gears, all the teeth on the input and output gears ripped completely off. Maybe ask the guys with lots of GTR drag racing experience, but that has been my observations. I have never seen one with a stripped 1st gear, in fact I don't think I have seen even one with a chipped tooth on first. That is because of the torque transfer though the low ratio (between the engine and the tyres). This evens out as the ratios (input versus output) become closer together, with 4th being 1 to 1 in a road ratio box.

Hi Adrian, let me start off by saying that I am not claiming that circuit racing is better than drag racing, or harder, or more difficult, or tougher. That can be the topic for another discussion. This one is about gearboxes. So, let's look at the facts; 1. In circuit racing the gearbox changes both UP and DOWN with load and speed 2. In drag racing the gearbox only changes UP with load and speed 3. I have heaps of data logs for the circuit cars that show the speed of the gearshift. In the 30 or so gearchanges per lap, even 1/100th of second delay in changing costs 6 seconds over the race distance. Last week we lost a race by 4/100ths. How important do you think that 1/100th of second saved in each gearchange is? 4. I also have a few data logs that show the speed of the gearshift in a drag racing event. Obviously 1/100th of second delay in changing gear cost 4/100ths of second over the 1/4. But the speed of the upchange is no different to that used in the circuit race. 5. In a circuit race, the driver often has to change gears in a sub-optimal situation, baulked by another car, accident avoidance, mid corner etc etc. This means the quality of the change is sometimes compromised by other events happening at the same time and G forces other than the straight acceleration experienced in a drag racing environment. Hence the chance of a bad/missed change is much higher in a circuit race than a drag race given equal driver skill. 6. In a drag racing environment I have not seen gearbox oil temperatures over 70 degrees, in circuit racing I see gearbox oil temps over 150 degrees. And for long periods of time, 10/15 minutes continuously. The driver still demands the same speed of gearchange at the end of the race as they did at the beginning. In the same 650 bhp race car, weighing the same 1400 kgs (inc the same driver), with the same tyres, I am going to see the same loads on the gearbox, the same speed of change, the same torque and rpm loadings whether it is used for circuit racing or drag racing. But the gearbox is going to do a lot more work in a season of circuit racing than it is in a season of drag racing. The difference occurs when you have an 1,100 bhp drag car, with 30" slicks on a properly prepared track. Now that's a totally different ball game, not because of the speed or violence of the gearchange, but due to the torque loadings on the gearbox exacerbated by the amount of traction available. PS; if I had a driver that "violently abused, flat-changed, shock-loaded and generally smashed about drag racing gearbox"........I would find a new driver. Because they are most definitely slow.

Hi Brad, I really liked the extra caster using the KCA332 adjustable bushes. Made a huge difference to the handling and steering response. Plus it took away that vague feeling around centre and added a bit of feel to the steering. The standard front rubber bushes where a bit worn on ours and it also removed a little shake, shake, shake going over bumps. I didn't lower ours very much (25 mm front and 10 mm rear) so I didn't need any camber correction. The front ended up a nice 0.5 degree negative and I adjusted the rear using the standard adjuster. It's all in the Stagea Suspension thread.

This is a picture of the boxes that the Whiteline stabiliser bars were in, showing the part numbers. They are R33GTR stabiliser bars, the R32GTR rear stabiliser bar (BNR26) won't fit. I had absolutely no problems fitting the front stabiliser bar, but the rear was a bit tricky. The standard bar is several mm smaller in OD than the Whiteline bar. So the critical measurement was the INSIDE of the U bend, as per the following photo; I have seen a couple of Whiteline GTR bars where the OUTSIDE of the U bend is the same as the standard bar. This means the inside of the U bend is 10 mm or so too close together. This means you can't do up the bolts on the D brackets. If that is the case with your bar then send it back to Whiteline, tell them how much it is too narrow across the U bend and they will replace it.

Yes, RB20/25/26 are all 25 mm.

The race GTR's use Hollingers, as the PPG's weren't available at the time. We do use PPG's in other race cars and they have been great. Just a regular service after 20 or so race meetings, we life them at around 1,000 laps or ~2,200 k's. Which is great for a dog box ,where we do 50 or so gearshifts per lap on some circuits. That's equivalent to about 8,000 runs down the 1/4. When I get around to upgrading the gearbox in the GTST, I will be using a PPG.

Interesting topic indeed, some alternative views for thought stimulation; I want most of my exhaust to drive the the turbine, not out the wastegate and waste all of that energy. I reckon one wastegate is all I would need, in fact zero wastegates has appeal. They had a blow off valve that was bolted onto the plenum and limited the boost. Sorta like a Champ Car. Yep, but they have uneven firing, I reckon an extractor flow 6 to 1 would be better if tuned correctly. Sorta like the R31GTSR homologated exhaust manifold. That's pretty much the same reasoning as I went for.

How about an $8K PPG? You should have a talk to Mike Vine at MV Automatics, you might be surpised how much power a $2500 upgrade on a GTS4 or Stagea gearbox will handle.

245 mm wide X 40% = 98 mm sidewalls 265 mm wide X 35% = 93 mm sidewalls

That's what I have for ours, but I haven't fitted them yet. I am waiting on pads, they should be here Monday. I will post it up and confirm that they fit only when I have actually fitted them. PS; be careful DBA4909SL is left and DBA4909SR is right.

That's why I suggested swapping over to the RB20DET inlet manifold, they come with top feed injectors standard. Then it is simple to fit GTR (also top feed) injectors or any number of cheaper (than side feed) aftermarket top feed injectors.

Tramlining is not realy a front stability issue, it is a separate effect of toe in. You can have car that is stable at the front but still tramlines. Conversely you can have a car that is unstable but doesn't tramline. You can also have a car with zero toe or even toe out that tramlines. It is usually more to do with SAI than toe, although caster can affect it as well.

Toe in is often described as a "stable condition". It makes the steering less responsive, so the front can feel a bit doughy, so the turn in to corners is not as good. However it is good for driving on freeways where you want a large sneeze factor. Small movements of the steering wheel don't effect the straight line running. This is similar for the rear, it makes the rear end less responsive to inputs (eg; throttle). So it can lessen the loose feeling you get when applying the throttle or backing off or braking. The downside is too much can reduce the manouverability in sudden direction changes. In a car where you're aiming for good handling you would run a bit of toe out on the front and maybe straight ahead on the rear, or a little toe in if it feels loose. Hope that helps:cheers:

The suspension movement and leverage ratios between the cars are totally different. You can not compare the spring rates between a car with a 1.25 to 1 movement and leverage ratios to a car with 1 to 1 ratios. If I stick a 12kg/mm spring in a car with a 1.25 to 1 leverage and movment ratios, the "effective" spring rate is 7.7kg/mm. The "effective spring rate" is what the tyre sees, and that's what matters when we are talking about traction/grip. Hope that helps:cheers:

I am not a chemical engineer, so please excuse me if I don't get into the science. We regularly send our oil (out of the race cars) to Castrol for analysis, they report back on; 1. The condition of the oil itself, whether it has retained its lubricating qualities or it has broken down and is no longer lubricating. This tells us if we are using the right oil/viscosity for the loadings the engine carries in the races. And whether or not we are running it at the right temperature (ie; the oil cooler is doing its job). 2. The contaminents in the oil, lots of possibilities here. High levels of unburnt hydrocarbons are a sign of too rich fuel mixture or leaking injectors. Burnt hydrocarbons are a sign of leaking valve stem seals (particularly exhaust). Glycol is a sign of a leaking head gasket. Bearing material is a sign of worn bearings. Aluminium is sign of worn/cracked pistons. Cast iron from cracked block etc etc The bottom line for us is we don't get reports back with issues in #1 that would indicate we are "cooking" the oil. If it is discoloured, it is because of #2, mostly due to the burnt hydrocarbons that get into the oil from the valve stem seals, past the rings etc. My previous comment was based on the posts to date that indicate no one was using low quality oil that is likely to suffer from excessive loading or temperature. Hence any discolouration was as a result of contaminents, with detergent action arguably being the difference when all other things are equal, ie; the same engine with different (but still high quality) oils. Hope that clarifies:cheers:

The rotor is attached to the disc by bolts that allow it to move in and out (ie; float). So, when you put your foot on the brake pedal and the pads extend, the rotor is free to self centre between the pads squeezing on it. If you have a slightly warped rotor, this lowers the amount of pad knock off as the rotor can also self centre when not braking. Since it is loosely mounted, even a slight touch on the pad will line it up ready for the next brake application. It is very usefull in the longer distance races as we always end up with some rotor warping from the extreme heat loadings. Pit stops add to the warping tendency as the rotors cool down a fair bit, expecially in that slow crawl they make us do down pit lane now. Hope that helps:cheers:

No :chairshot not rice power, rice colour :Pimp2:

I always thought GReddy was Gee (as in whiz) and Ready (as is ready, set, go) :burnout: They have a GRex as well, so I reckon that's Gee (as in whiz) and Rex (as in the wonder dog). No reflection on the quality of the product of course.:innocent::innocent::innocent:

One of 3 areas usually Shire, Revesby, Yennora:cheers:

One oil feed is plenty.

Nope, you are supposed to turn left before the gravel......or is it right.... :confused: :confused: :confused:

My 20 cents worth; 1. One piece rotor is all cast, then hardened. Two piece rotor has a cast disc bolted to an an alloy centre. So it is noticeably lighter and transfers less heat to the wheel bearings, wheels, CV's, uprights etc 2. The durability of the parts around the rotor (wheel bearings etc) are improved by it being two piece. If the rotor is made of the same material and is the same dimensions, then it will not, in itself, be any more durable, Except you don't have to replace the hat when the rotor wears, so in theory it should cost less to service. 3. If the rotors are the same dimensions and solid mount, there is no real difference in stopping power. 4. Probably not worth the extra cost on a road use only car, does have a bit of rice value for some though. 5. Definitely worth doing on a race only car, saves heaps on wheel bearing and CV servicing, plus the lighter unsprung weight is worthwhile having. Note; not all two piece rotors are the same, for example there are floating and solid mount rotors. A floating rotor definitely improves the braking performance and consistency, as it eliminates/limits pad knock off in many cases. Hope that helps:cheers:

If you want to run the VVT, then the R33GTST wiring harness and PFC would be the go. This means you use all of the RB25DET sensors so they match the harness plugs and the PFC. If you don't want to run the VVT, then swap all of the sensors over from the RB20DET, plus the inlet manifold and injectors (they are top feed so much cheaper to upgrade than the RB25DET side feed). Then you can use the RB20DET wiring harness and PFC.