Big Rizza

I think the building is part of the experience - I don't think I could do it any other way!

I was budgeting 5 days per month at 5 hours per day towards the project (I work away on an oil field, so I have plenty of days at home with no commitments). They claim 100 hours to build, so that would take 4 months by that reckoning. Double that to eight months to compensate for any inevitable blowouts, and then add another 4 months to compensate for the fact that I am incompetant, and I arrived at a figure of 12 months to get it on the road. And that photo is great. Unfortunately I can't say the same about that engine block!

Cheers for the feedback CEF11E - much appreciated. I'll keep your positive feedback on the Elfins in mind when I am shopping around. Has anyone had any experience with the Leitch clubman kits? Their website claim: This seems an insanely cheap price for a road registered clubman - most are up at around $40k for a basic vehicle. Can anyone tell me anything of their quality, both of product and of service? Cheers

A turbo 20V elfin? That would be a little scarey I reckon! I think the stock 4AGE 20V will do it for me! How was the Elfin for quality, ease of construction etc (aside from the fabrication work to fit the custom engine - i will stick to the standard motor)? All the parts fit together well? Or was there plenty of stuffing around with parts that are supposed to bolt straight in?

Glad you enjoyed the discussion

Hey all, When I originally bought my R32 GTS-T sedan, it was because I needed something practical (i.e. 4 doors plus boot) yet something that would be fun to drive. Now that the Skyline is a second car, and now solely doing weekend duties, I am considering upgrading. The problem is, nothing that manufacturers have built seems to satisfy me... So I am thinking of building one myself! Perhaps one of the Lotus Super 7 clubman replicas from Westfield, Elfin, PRB, etc. I figure dropping a standard 4AG 20 valve would give more than adequate performance in a car that weighs less than 700kg. Has anyone had any experience with these? Was it a rewarding experience? Any pitfalls to avoid? Any manufacturer to recommend? Was it worth the $$$? Any feedback would be appreciated!

Anyways, this seems to be going around in circles a little. I can't help but read in a level of frustration on your side of the information super highway, which absolutely wasn't my intention. I'm not trying to piss people off! I admit to a smidgeon of frustration - I think I took it a little personally when you trashed my physics and maths skills . But seriously, I'm just trying to have a friendly discussion! I don't think 0-100km/h is the best measure of performance - I have made that pretty clear. And I also think that people give this figure too much bearing when measuring performance. It's not completely "useless" as I said in exaggeration at the start, but I think that a distance, a speed and a time are all required to get a decent idea of performance. For example, a 0-400m time plus terminal velocity. Or a 0-100km/h time plus distance travelled. It is similar to measuring a vehicles performance purely on the peak power number (or even power to weight ratio). It doesn't give the full picture!

Your post hadn't appeared yet when I wrote that, so it wasn't in response to your post immediately prior. What? It's impossible for one car to get off to a good start, and have a more powerful car then run it down? I already said the numbers themselves weren't an accurate model of real life - and that point was very much an aside. Just merely pointing out that two cars with identical 0-100km/h and 0-400m times might not be neck and neck the whole way. But the core of the arguement is that 0-100km/h times are not the best representation of a vehicles performance. And at what point does the lead change multiple times? One car gets a better start, the other chases it down. One change in leader. One. And tF&tF is a fantastic movie .

You are exactly right - but my point is that people use this figure as a definitive measure of performance i.e. the car with the lower 0-100km/h time will be faster. My point is that this is not true! A reminder of THE VERY FIRST THING I SAID, and the essence of what I am saying: That is what this discussion is about.

I will just re-iterate again that comparing 0-100km/h times and 0-400m times doesn't necessarily proove or disprove what I am saying. Taking my V8 vs turbo example again, the V8 was ahead by about 2-3 carlengths at 100km/h, but the turbo was accelerating harder - therefore above 100km/h the gap would be closing. What if that gap continued closing and became zero at 400m? The two cars would have identical 0-100km/h times AND 0-400m times. One would assume they would be neck and neck the whole way, based on these figures, where in fact the V8 lead the entire race (other than the instant in time at the start and end). (Just fuelling the fire people )

From your comments it is immediately obvious that you have entirely missed the point of my post. Firstly, I am 100% aware of the inaccuracies in modelling the distances travelled in my example. You don’t need to point them out to me. A better approximation for distance would have involved curve fitting and integrating under the curve to find the distance travelled. But nevertherless the point of the example was to show that the V8 would have been in front, despite identical 0-100km/h times, and if you don’t get too hung up on the over-simplification of the model it would be plain to see that. As for the models themselves, they are over simplified and no vehicle in the real world would accelerate with the characteristics shown, and I am happy to admit that. But the models I have used were not supposed to be 100% reflective of what will happen in the real world. Don’t get hung up on them - they were merely examples literally made up on the spot to demonstrate my point. And my point is that 0-100km/h times do not reflect the distance travelled over that interval. Without knowing the distance travelled, there is no way to tell which car will be in front. And that is indisputable, I'm sorry to say. If you had understood this point, you would have realised that your point about gearshifts skewing 0-100km/h times actually gives credit to my argument rather than debunking it. In fact, the more variables you add, the more credit my arguement has. Yes it makes the model less representitive, but the model isn't the point of my arguement. More variables create more and more differences in the characteristics of the way a vehicle accelerates - therefore there will be more difference in the distance travelled from one vehicle to another over the same speed interval. Picking one point in time and measuring speed will not give an accurate indication of which vehicle will be in front, unless both vehicles have similar acceleration characteristics. Obviously the 0-100km/h time has some merit – my saying it to be “completely useless” is obviously an exaggeration. A vehicle that does 0-100km/h in 24 seconds will obviously be beaten by a vehicle a vehicle with a 0-100km/h time of 3 seconds. Fair enough you can make an educated guess of which car will be victorious in a race based purely on the 0-100km/h time, but what I am saying is that this absolutely should not be the difinitive measure of performance that so many people consider it to be. Personally, I don’t know how anyone who has understood my argument can disagree with it – 0-100km/h times just don’t give indication of the distance travelled, and therefore don’t show which vehicle has travelled further, and therefore don’t show which vehicle is in front. It’s not rocket science. And now you want me to go and collect vast amounts of data to try and prove this point? Well, I have had quite a few people agree with me so far, so maybe you should be going to get vast amounts of data to counter my point? Perhaps when I get home tonight I will put out an old motor or wheels and make up a comparison… The quarter mile time vs. 0-100km/h time isn't really what I am trying to say - Really I would need a 0-100km/h distance compared to 0-100km/h time comparison to give the definitive answer - but since you asked I grabbed a couple of comparisons from www.supercars.net, (although i'm not going to rely on this for my point as I don't trust a lot of these figures...). mazda rx8 (2002) - 6.1 to 100 and 15 to the quarter volkswagen golf Gti (2005) 6.5 / 15 Mazerati Bora (1979) 7.1 / 15 Three vehicles which travel 400m in an identical period of time, but reach 100km/h up to a second apart. Lotus Carlton (1989) 5.4 / 13.5 Honda S2000 (2000) 5.5 / 14.8 The Honda S2000 is only 0.1 of a second slower to 100km/h, yet the gap is 1.3 seconds over a distance of 400m. VW Golf R32 (2002) 6.1 / 14.1 mazda rx8 (2002) 6.1 / 15 Identical times to reach 100km/h, but the golf travels 400m in signifficantly less time Ferrari 360 Modena (2000) 4.3 / 13 Dodge Charger SRT-8 (2006) 5 / 13 360 Modena reaches 100km/h in short order, but they cover 400m in equal time. I don't really like supercars.net's figures, so I won't continue until I am home with numbers from motor or wheels. Don't get me wrong, it's just as easy to pull out comparisons of similar vehicles: Toyota Supra RZ (1993) 5 / 13.5 Jaguar XKR (2004) 5 / 13.5 But nevertherless that doesn't disprove my point - having some examples go one way and some the other just compounds my theory that 0-100km/h doesn't indicate who will win. Anyways...

The whole circuit vs. street vs. strip debate is somewhat outside the scope of this discussion

Sounds good to me

PSI GTSII kind of beat me to it, but I have my own example: I’ve always been really good at grasping this sort of thing (it’s the engineer in me), but terrible at explaining it! If I break it down into sections, including time, speed, acceleration and distance all together, maybe people will understand better. Taking the V8 vs turbo route: 0-1 second The V8 accelerates harder than the turbo over this increment because of its strong torque. The V8 gains 20km/h compared to the turbo’s 10km/h. The V8 is accelerating harder than the turbo (speed rising at 20km/h per second vs 10km/h per second). The speed of the V8 at this point is now 20km/h, the speed of the turbo at this point is 10km/h, so the V8 is pulling away from the turbo. At 20km/h for one second, the V8 will travel 5.5 meters. At 10km/h for one second, the turbo will travel 2.8 meters. So the V8 will be 2.7 meters ahead of the skyline after 1 second. 1-2 seconds The V8 keeps accelerating as before, gaining another 20km/h over this second. The laggy turbo starts seeing positive boost pressure and accelerates 15km/h over this second. The total speed of the V8 is therefore 40km/h (20km/h + 20km/h), and the total speed of the turbo is now 25km/h (10km/h + 15km/h). The V8 has a higher speed than the turbo, and is therefore pulling away from the turbo, increasing its lead. At 40km/h for one second, the V8 will travel 11.1 meters. At 25km/h for one second, the turbo will travel 6.9 meters. The total distance travelled by the V8 will be 16.6 meters (5.5 + 11.1). The total distance travelled by the turbo will be 9.7 meters (2.8m + 6.9m). So the V8 is ahead by 6.9 meters after 2 seconds. 2-3 seconds The turbo continues to spool up and acceleration improves again, gaining 20km/h this second. The V8 also gains 20km/h. At this point the ACCELERATION of both vehicles is the same – both are gaining speed at the same rate (20km/h gain per second). But the SPEED of the V8 is higher at 60km/h (20km/h + 20km/h + 20km/h) vs 45km/h for the turbo (10km/h + 15km/h +20km/h). So even though the acceleration is identical, the higher speed of the V8 means that it continues to extend its lead over the turbo (it should be obvious that the car travelling faster will be pulling away, ya?). At 60km/h for 1 second, the V8 will travel 16.6 meters. The total distance travelled by the V8 is now 33.3 meters (16.6m + 16.6m). At 45km/h for 1 second, the turbo will travel 12.5 meters. The total distance travelled by the turbo is now 22.2 meters (12.5m + 9.7m). So the V8 is now ahead by 11.1 meters. 3-4 seconds The turbo is really starting to cook now, accelerating 25km/h this increment, vs the V8s 20km/h. So at this point, the ACCELERATION of the turbo is better than the V8. It is gaining speed more quickly than the turbo (25km/h per second vs. 20km/h per second). The total SPEED of the V8 is now 80km/h (20km/h + 20km/h + 20km/h + 20km/h) and the turbo is now doing 70 km/h (10km/h + 15km/h + 20km/h + 25km/h). The V8 has a higher speed than the turbo, so it continues to extend its lead over the turbo. EVEN THOUGH THE TURBO IS ACCELERATING HARDER (25km/h/sec vs 20km/h/sec), THE SPEED OF THE V8 IS HIGHER (80km/h vs 70km/h) AND THEREFORE THE V8 IS STILL EXTENDING ITS LEAD!!! At 80km/h for one second, the V8 will gain 22.2 meters. The total distance travelled by the V8 is now 55.5 meters (22.2m + 33.3m). At 70km/h, the turbo will travel 20m in one second. The total distance travelled by the turbo is now 42.2 meters (20m + 22.2m). So the V8 is now ahead by 13.3 meters. 4-5 seconds The turbo is now on full boost, gaining a full 30km/h over this second, vs the V8s 20km/h. The ACCELERATION of the turbo is now significantly greater than that of the V8. The total SPEED of the V8 is now 100km/h (20km/h + 20km/h + 20km/h + 20km/h + 20km/h), and the total speed of the skyline is now also 100km/h (10km/h + 15km/h + 20km/h + 25km/h + 30km/h). The speed is identical, so no car is gaining or losing ground against the other. Both cars will cover 27.7 meters in one second at 100km/h. So the total distance travelled by the V8 is 83.2 meters. The total distance travelled by the turbo is 69.9 meters. The V8 is ahead by 13.3 meters. There we go! Two cars with an identical 0-100km/h time, but in a race to 100km/h, the V8 wins by nearly 3 car lengths!

Even with the CVT, I doubt the Bravo would keep with the skyline. The Bravo has a peak power of eighty-something kilowatts as I said, and I reckon that even with gear changes, rev changes etc. my peak power of 160+kw would result in greater average power. Plus skyline is lighter .

I DID say that extrapolating the formulas I chose wouldn't be reallistic It is just as unreallistic for the family car, which accelerates at a constant and linear rate for all eternity.

Well, if you don't like it, ignore it! If the original example works in your head better, use that!

To some degree yes. All else equal, the torquier car will win. But just as power alone will not win races, torque alone doesn't win races either. The Mazda Bravo turbo diesel I occasionally drive for work makes more torque at 2000rpm than the RB20DET powered Skyline I own makes at its peak, but with a peak power of just eighty-something kilowatts at 3500rpm, there's no way it would keep up with the skyline.

The GTR will launch harder, so it will be ahead of the GTST. The leading car will have covered more distance than the trailing car (otherwise it would be behind the other car, right?). Therefore, the GTR will have covered more distance than the GTST, and would be leadin the race. The GTST accelerates harder than the GTR once its tyres hook up properly, so it manages to reach 100km/h at the same TIME, but the GTR is already ahead by several car lengths after the brutal launch, so it has still covered more distance.

Think of it like this. Both cars accelerate for 10 seconds. Car one accelerates very quickly to almost 100km/h in the first one second, then slowly accelerates to 100km/h over the next 9 seconds. It spends most of its 10 seconds at high speed. Car two accelerates very slowly for the first nine seconds, the quickly accelerates to 100km/h at the end. So it spends most of its 10 seconds at low speeds. Both cars will reach 100km/h at the 10 second mark, but car one will have travelled more distance because it has spent more time at higher speeds than car two, so the AVERAGE speed over 10 seconds was higher. This is an extreme example, but it applies to real world situations - a more reallistic example might be a stock GTR (all wheel drive) and modified GTST (rear wheel drive). These might have the same 0-100km/h time of 5 seconds, but the GTR will launch harder, and will hence get ahead quickly and cover more distance before the 100km/h speed is reached. If that makes any sense to anyone...

No V8 for the Lexus GS hybrid. It's a V6 with the power of a V8 and the economy of a 4cyl. Apparently. Dunno if that was what you were referring to... There will probably be a V8 hybrid in the new Lexus LS, but that's not here yet.

I chose those formulas with the 0-100km/h sprint in mind, and to extend them outside that will make them less representitive of a real world situation - they are simply too primitive to be extrapolated and still reflect real world situations. Particularly the turbo car, which by the formula will keep on accelerating faster and faster at a rediculous pace, but for the fun of it I will do it anyways Due to the electric car reaching max speed at 100km/h, the after 10 seconds the family car will start closing the gap. Similarly, after 10 seconds, the faster acceleration of the turbo car at high speed means it will start running down both the family car and the electric car. At the 15.0 second mark, the turbo car will catch the family car. At the 15.4 second mark, the turbo car will catch the electric car. At the 15.8 second mark, the family car will catch the electric car. The turbo car runs a 16.3 at 265.69km/h (see what I mean about unreallistic ) The family car runs a 17.0 at 170km/h The electric car runs a 17.7 at 100km/h Whilst the 0-100km/h was a reallistic enough to show what could happen in the real world, this quarter mile situation is unlikely. Even more unlikely is the turbo's standing kilometer - 22.1 seconds at 490 km/h. EDIT: Oh, and here is the speed graph for the vehicles And the turbo car does 0-1000km/h in 37.1 seconds, and is accelerating at over 60 g's by that point .

I'd go the Toy-Boat-a

Hey all, There seems to be a lot of people who seem to be using the 0-100km/h time as a bench mark for vehicle performance. However, in my experience the 0-100km/h time is not a great reflection. Why is that? Many of the real world traffic light grand prix events are from rest (0km/h) to the speed limit, or just over it (so about 100km/h), so surely this would be the definitive measure of a cars on street performance? Not really, no. I will use an example to illustrate my point. Three cars line up at the traffic lights. All three cars have an identical 0-100km/h time. For simplicity, let's make it 10 seconds. The speed limit of this road is 100km/h, so it will be a race to the limit. Nothing illegal here Car number one is a concept vehicle (why it's at the lights I don't know...). An electric vehicle. It doesn't make much power (in fact the top speed is only 100km/h), but it is ultra light, and has 4 in-wheel electric motors giving full torque from 0 rpm, meaning it can charge of the line hard. Car number two is a regular family car. The long geared automatic with big six cylinder power means that acceleration is fairly constant throughout the rev range. The final car has a big turbo, front wheel drive, and manual gearbox. This makes it tricky to get off the line, but once it's hooked up and the turbo spooled, the acceleration is very good. The image below shows a representation of these three cars' acceleration curves. As you can see, all three will hit 100km/h at the exact same moment. (for those who care, the electric car's speed was modelled by a quadratic equation speed=-(time-10)^2+100, the family car by a linear equation speed=10xtime, and the turbo by another quadratic equation speed=time^2) So it's a race to 100km/h, and all three cars have an identical 0-100km/h time, so it should be a pretty close race, right? WRONG! The hard launching electric car gets the jump from the start, and wins by a full 45m over the family car, and a whopping 90m over the turbo car - that's about 18 car lengths!!!! (For those who care, distances were obtained by integrating the speed equations stated earlier. If I made any errors then they were deliberate and hence I don't care - don't bother pointing them out, the electric car would still win ) This is obviously an extreme case, but I think it illustrates my point nicely. 0-100km/h times are stupid.

http://www.prestigemotorsport.com.au/modul...php?StockID=449