ShopTalk Forums | Aircooled VW Tech & Restoration Help

Yes, straight cut gears do free some power, but the main reason why its done today in some cars, are the fact that it is easier to dogshift withém. Many late 60ies and 70ies race cars had them. in the 80íes they became more rare, because development sortof overruled the gaines by the straight cuts.
Now we hardly ever see them.
T

Porsche never used them, not even in the 917... They used fully synchronized gears all helical cut, just like their production cars....

I know where a Hewland VW gearbox is that has a full set inside it..

I love the sound of a bunch of noisy straight-cut gears. Every pure-bred racing tranny I'm aware of is designed with straight cut gears.

There's a sexy set.

Sub though....

Road Atlanta is only about an hour from you, Jake. The Petit Leman/American series goes there every year or maybe you can share some track testing time with Panoz. Hell, they're right down the road. Talk about your cool -a** test facility.

Yeah... And I also live 2 miles from the Atlanta dragway, but I doubt John Force would let me share a pit with him nest time the Southern Nationals roll through...

Its all just wishful thinking, a venture like this would drain my R&D account for the next 10 years...

Not only would it drain the R&D account, it would leave NO time to make a living!

The price to get test time at Road Atlanta was over $5000.00/day a few years ago. Now that the track is booked 52 weeks a year I imagine it cost more than that.

torque is very cool.....


79 trans am is factory 220 hp and 330 ft/lb of torque....

and it is a a little more thatn that cuz I have roller rockers, camshaft, and edelbrok manifold......


I am putting on stainless exhaust with a crossover.....more torque.....


so......torque is good.....

and air coooled it fun

so my garage is

71 super
79 trans am
67 gto

got all bases covered......

definately different driving feel outta all three cars....

what a hobby!

big al

I remember seeing a water wheel, on the history channel, that produced about 350hp and over 100,000 ft-lbs of torque. It wouldnt be very much fun on any track. Like other people have said, theres alot more to racing the HP and torque.

It's really academic anyway. At 5252 rpms is the crossover; below it is all about torque and above that hp takes over until the engine characteristics run out of preferred air/fuel ratio.

If you want an engine to last, ie. street/everyday driver, then the answer is torque of course. If you are more interested in racing/keeping it revved up, then go with the higher hp numbers remembering that the life is dropping due to more rpms wearing out/putting more pressure/heat into the engine.

I am having Jake build me a large 'Hero' and he and I have talked at lenght about what I will use it for, and right now, my engine will probably peak at 6500 or a little less (maybe 6000/6200). That's alright with me as I hope to keep it going for many miles on the road. Just like his Plague, I plan on taking long road trips and need total reliability, but want the high power for some very occasional trips to auto-x or down the track for fun . I am not building a 'race' car, just a very super sleeper ghia vert!!!

Kelly (Cohibra)

HotStreetVw wrote:I remember seeing a water wheel, on the history channel, that produced about 350hp and over 100,000 ft-lbs of torque. It wouldnt be very much fun on any track. Like other people have said, theres alot more to racing the HP and torque.

Sure.. Imagine that baby at Bonneville with the tallest geared 3 speed in the world!

Is that the Kaaz or Shalack Gearset in that 5MT?

I would so love to see a AC TIV win some sort of endurance race dominated by Water coolers.

Hi

Diesel power in sports cars is not so new.
check this out: http://www.supercarsite.net/c_30_cdi_am ... _coupe.htm
Look at the torque and the max RPM and top speed.

Hermann

Here's the stuff that Bosch had on the Audi racecar:

As development partner, Bosch supplies the specially adjusted high-pressure pumps and piezo-inline injectors for the common rail injection system installed in the R10 TDI. Its engineers also have used the specific racing know-how of Audi Sport as the basis for developing the new electronic control unit for the car's 12-cylinder engine. When developing the injection system, the greatest challenge was the variable control of the extremely high injection pressure. Bosch also supplies the telemetrics system that ensures an uninterrupted transmission of data from the vehicle to the pit during the race.

FYI, if you care.

Q

I have to throw in my 2 cents also....

V12, 5500cc, 650hp, 1100Nm, 3000 to 5000rpm rev range.

from Audi: "The ignition pressures also reach values never previously seen in any Audi engine. "

dont forget a diesel engine cannot be compared directly to a petrol engine. 5000rpm is high revving for a deisel engine, extremely high revving. As many people on this site keep saying, hp=tq/5xxx (I dont remember and i dont care). Power is made by fuel burning. more fuel = more air.... As the equation states, any engine revving at half the oposition, needs to produce twice the torque to be equal on the track.
Dont forget that diesels dont detonate, the fuel is injected at specific amounts for correct combustion at specifi timed intervals (dont argue this point, its not too easy to write).
Because the engine doesnt detonate, it is possible to use really high boost pressures. I know of enignes that are used as generators that run just over 5 bar with a life between teardowns of roughly 16000hrs. This said, I wouldnt be surprised if Audi is using boost in the 5 to 6 bar region. Not to forget either is the fact that most deisel engines run an industry standard of 16:1 CR.

What am I saying?? Well, i forgot while writing this.

Torque is power and power is torque. To get power to the wheels, you need to burn fuel. Its the quantity of fuel that dictates the power made. The torque enignes that is what the T4 guys talk about is an engine that is efficient in using this fuel lower down in the rev range. While the peaky high revving engines are more efficient in their highr designed rev ranges. i am sure both can be made to do either.
I would put money on the fact that if the average T4 engine made its big heaving power from 3000rpm to 9000rpm, you guys would also use the revs, not changing at 5000 simply because its a torquey engine.