DoughBoy

Bring your bike, can line up against me

In the rain on the side of the road?

To suit what turbo(s)?

I'm coming to bench race! Har har!

Trick setup, but there is no way in hell that car would need twin throttles. Just on turbo size alone it's not going to have the airflow. Referring to other (drag) cars, it looks like the change from a single 100mm to twin xx ones is at the 1500hp mark...

What are the rules with regards to vehicles? Bikes, street registered, comp/drag cars - track prep, timing etc?

My bet is 32 or 33 N1 turbos

Hey Farmer Joe, that cotton field looks 'bout a'ready to be a' picken. Yeehaaw.

My bad, ok I did my homework to find out what it would have gone on..... Hahaha, go the John Deere products! p.s. Been waiting a while to throw the Truck turbo comment at you

T66? Why would someone use an old truck turbo design on such magnificent late model technology cars? Surely one would see better use on a Canter than a Skyrine? >

So in effect your trick, no doubt cheap and mass produced turbo combination, weighs approximately 1.5 times a single 2530 rotating combination. Apples for zuchinni flowers maybe? Doing a gross injustice and highly wrong calculation on it, 2530= exducer dia = 60.1mm, mass = 1, Inertia 903 T66 = exducer dia = 91.5mm, mass 1.5, Inertia 2093 So 2x 903 =.... 1806? Also, I'm assuming that the measured reduction in frictional losses are from equivalent sized bearings? Take into account that most Txx series use the large 3/8th (9.5mm) shaft, where a 2530 has a 5mm shaft size? So the actual bearing surface is twice as large assuming same width, which is probably wrong as well since the larger shaft would need a wider bearing surface too? So if you assumed the bearing was only 1.5 times the width, that would still give you a surface area 1.5 times the amount found on 2x 2530's, less 30% for innovative design of the ceramics. So 20% more friction end result on the T66? Yeah it's late and I am playing devil's advocate, a well as making absurd guesstimates. The T66 probably does everything the 2530's do, and is easier to work on - and gets alot of ooohs when you pop the bonnet

Yes but since inertia is a square of the radii it is not proportional. If you half the radii you quarter the inertia. Split pulse housings have a higher efficiency than normal open housings.

This is about street cars, that might see a mild amount of circuit work. Drawing comparisons to F1 and "ideal" systems is bollocks, cause it ain't going to happen this weekend. Oh how large is an F1 motor? 1500cc? Have you seen a F1 turbo? UAS John has had a couple come through his hands from Keith Carling's car, and they aren't that big at all - hell two were used on a 3,000cc VG30 engine. So what's the deal there? They also spun at unrealistic levels to maintain sufficient boost pressures - I think the comp map went up to 4 bar? Use a real world example - say 1000hp on an RB26. From the Garrett catalogue, this would see a combination of either 1/ Twin GT30R turbos or 2/ One GT42RS turbo Looking at the max turbine efficiency graph the GT42RS comes in at 69%, the GT30R at 72%. I'm not sure I can trust Garrett's published figures, but take it with a grain of salt they are correct. Where is the uber efficient large wheel here? If the pressure differential created say "x" amount of force, bearing in mind that both the inertia and turbine efficiency of the smaller turbo is superior, how in hell would that spool a large turbo quicker?

AFAIK cones weren't part of the curriculum

The problem is actually getting the wheels seperate to weigh them - you can extrapolate as much as you want but in the end it's only going to be an approximation. I think in the end - large single for drags, small twins for circuit/street. It's been proven time and time again, but like I said you can make any combination work with sufficient resources and planning.

I failed physics, so I know this is a sarcastic stab at me

I guess looking at a performance application on a Skyline, you could run twin 3 inch pipes off twins, or a single 4 inch off a single? Maybe even a 4.5inch, although this would impinge on your arguements that a single has more space - ever tried to fit a pipe that size anywhere on a car? Twin 3 inch area = 14 sq inch Single 4 inch area = 12sq inch Also the flow on the turbine inlet/ turbo flange could be another comparison. Funny side story, they have actually started to put flange size restrictions in on turbo drag classes in the states, guess there must be some hidden horsepower in having the largest flange possible?

Oh and for inertia: Inertia = radius of gyration^2 x mass As you can see, a large wheel will dramatically increase inertia.

Ahh if you want to quote friction loss from twin turbos, how about the inherant flow advantage from twice the turbine exit area on twins, and the cooler running from having twice the coolant capabilities?

Twins have got the advantage over singles due to lower inertia, something that no one has made reference to or even acknowledged in this thread. Lower moment of inertia, quicker spooling time. And another point in the large single's favor is the maximum pressure ratio is significantly larger than a set of twins. All the more pressure to boost you with, my dear. Both have their good and bad points, and either will work pretty well as long as it's matched to the application. I think alot comes down to preference (rice factor?) and budget.

They are standard.

What ever happened to my good friend Inertia?

New motor? What happened to the old motor?

Checked out the classes, apart from the ANDRA S/C ones there are a couple that I don't know... OZ 6 I suppose is Holden V Ford, Compact Xtreme ? and Tuff Tech ? I have no idea about - are they heads up? I liked the event last year, even though there were alot of cars quicker than me there was still a chance of winning I think how the classes were drawn up and the fact they were heads up was a good thing.

HKS 3040 turbo kit RB25 Selling the turbo kit off my GTS-t. Custom ceramic coated low mount manifold, HKS 3040 turbo, exhaust to cat, AFM pipe. Turbo made 294rwkw @ 17psi, no wastegate. $2,000 RB25 R33 GTS-t Power FC w/Hand controller Tuned for the above turbo kit $900