Gearbox for 300 bhp

[Anthony]

Thanks Mickrick, lovely but a little expensive

[Mickrick]

Don't know why, but everythink I like, turns out to be expensive! 😬

[Anthony]

Been there too, and when it comes to sell its not worth much 😬

[Caesar]

I never got any improvement and now it sounds worse! I really think it is shot and in less then 2,00 miles but with (alleged) 260bhp it seems it might be expected>

 

here

 

CoSwoRth it!

 

Edited by - Caesar on 2 Aug 2008 10:43:41

[Mike Biddle]

Me too Mickrick, why is that?

 

The Drenth together with a carbon prop is the last major thing I want for my car to make the driving experience more pleasant.

 

When I were a lad I worked part time on a farm and used to drive tractors, my favourite was a David Brown 88o which will reveal my vintage to those among us who are in the farming fraternity.

 

It had a lot of gears, 12 (forward) I think, and the change on my quiafe straight cut sequential is only marginally better. Don't get me wrong here I love it, it has served me well over 10 years, and continues to do so but the Drenth change mechanism is so much slicker.

 

Incidentally, limitations on gearbox input RPM is the main reason for limiting the RST RPM to 10,200.

[Mickrick]

It's called taste Mike. 😬

 

You talk of tractors. Coincidently, I've always had a hankering for a Field Marshal. 🥰

[k80rum]

Sorry for dragging this off-topic, but seeing as how we're coming clean I've had a secret passion for a Lanz Bulldog

here and

just because they're huge single-cylinder machines, which seems all wrong .

 

I'm sure there's another German single cylinder, 7 Litre vintage tractor that I saw doing passenger rides at the Goodwood Revival a few years back, but I cant remember for the life of me, what it was called.

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

 

Edited by - k80rum on 2 Aug 2008 10:35:00

[Mickrick]

Not only 7ltr single, but two stroke! your second link is a Field Marshal.

[Willie.]

Does anyone know what gearbox is in this?

 

Change is a bit brutal

[k80rum]

I think it's a Quaife sequential isn't it? I'm fairly certain that's what the prototype used. It's certainly what Mike Biddle's got in his..

 

I've no direct experience but from what some people have said, the shift is claimed to be a bit agricultural compared to others, but it's a tried and tested box and one of the most popular.

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

 

Edited by - k80rum on 3 Aug 2008 14:14:20

[rgrigsby]

It's the original Quaife sequential box in the RST-V8, I've not driven the V8 but I have used it in a few other cars and it is fairly agricultral. Apparently the new Quaife box is a lot better.

 

Rob G

www.SpeedySeven.com

[Willie.]

Thanks lads.

 

Is the Elite box any better?

 

Although to be fair on the box, he/it doesn't really blip on downchanges.

 

[k80rum]

The Elite box is lighter than the outgoing Quaife equivalant and was designed from scratch (like the new Quaife), but is still fairly new and quite a few owners seemed to suffer teething problems as the design was improved.

 

Some seem to have stuck with the Elite and are happy with it, some wanted reliability and support that the early gearboxes and an emerging company didn't always seem able to provide so it appears to be a bit of a 'Marmite' product in that different owners seem love or hate it. The gearbox is a bit cheaper but requires a slightly longer propshaft which pushes the price back up.

 

One of the main problems is that at 200 lb/ft capacity, it's probably running at the edge of it's design specification for several of its adopters. I think the old Quaife box is of a similar capacity but has had longer to mature. I guess once you're close to the torque capacity of any gearbox, failures are more frequent and tend to be influenced by driving style and the use to which the box is put.

 

Drenth is another alternative as has been mentioned, although they're quite costly. They receive a lot of praise, but I'm not sure there's a Caterham running one of these so direct feedback is hard to come by.

 

The new Quaife sequential gearbox has been built for the high-power type-9 market and seems to be the box of choice - it's currently best of breed because Quaife have designed it specifically (the old one was an adaption of the old type 9 gearbox, with the sequential mechanism packaged onto the tail), so the gearchange is likely to be improved too. They're still fairly new but with Quaife's design knowledge behind it, it's unlikely to be very troublesome. For the money, it's pretty much on it's own in being able to handle the bigger torque figures. This is what you'll get if you specify the sequential option on a factory R500.

 

Downshift blips are likely to be a driver function or a trick ECU. Pro-Shift, who do paddle shift conversions for most sequential boxes have a throttle blipper, which seems to need fitting onto the inlet manifold. Some ECUs have the ability to cut revs (and conversely could blip the throttle) when a gearchange is detected. The Emerald K3 in fact is halfway there and is capable of cutting the throttle for different periods depending on gear, when it sees a gearchange (or clutch pedal) movement. I'm campaigning Emerald at the moment to have the downsift blip functionality added to a future release.

A nice cheap way of getting the same thing would be for the driver to do the blip himself of course

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

Edited by - k80rum on 3 Aug 2008 15:05:01

 

Edited by - k80rum on 3 Aug 2008 15:06:47

[Willie.]

Darren,

 

Very, very informative. Thanks.

 

I always used to hate sequentials, but I'm very slowly warming to them. Must say I like going from 6th to 2nd in one shot.

 

Willie

p.s. Do you mind if I blatmail you re: a different subject?

[Irrelevant]

k80rum: As far as the downshift blipping goes . . . I reckon it would be quite simple to bodge oneself. Take 1 pressure switch (e.g. translogic's GP sensor), a throttle bypass valve (IACV), an injector, and a simple box of tricks. Link pressure switch to down shift motion so box of tricks knows you are down shifting. Box of tricks then tells IACV to open for a period to let air into the engine whilst squirting a smidgin of fuel in. With a couple of fiddle factors for the injector and IACV duration and a lock out switch to turn the whole lot off, job's a goodun

 

 

[k80rum]

Willie: Glad it was helpful .There are no doubt others on here better qualified than me to talk on the subject, but that's what I've picked up from looking into it. RE: Blatmailing- no problem.. .

 

Adam: . You make it sound quite tempting! The way you've explained it sounds like what the Pro-Shift actuator doobry does (for quite a bit of cash no doubt). Your example was much easier to imagine though

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

 

Edited by - k80rum on 3 Aug 2008 15:36:27

[Irrelevant]

k80rum: Can the Emerald switch maps quick? Maybe the pressure switch could flip the maps (to give some fuel with no throttle opening) and open an IACV, then switch maps back again? And thus, avoid the box of tricks I mentioned. Problem is, with 4 independent TBs, it's not as simple as one IACV on a manifold. And I don't even know if IACVs act quick enough

It's probably far easier just pestering Emerald for a bit of downshift code though

 

 

[k80rum]

Yep, map-shifting is very quick and it can be done on-the-fly. I'd guess although an IACV traditionally moves quite slowly, it could move quickly if it was told to. As you say though, whether this would fast enough for a fast sequential change is another matter. The CC IACV is effectively a solenoid isn't it? For a fast downshift I suppose it'd have to perform it's travel in the ms range

 

I suppose that in order to get the blip you definitely need an air valve of some sort (unless you opt for a fly-by-wire throttle) in order to get the revs up enough for the blip. Otherwise you would never be able to get the rev increase you needed, even if the driver kept the throttle open slightly on the downshift.

 

I'd guess that this is one reason Emerald wouldn't end up adding it into the software either - you'd still need additional hardware in which case you'd probably go to someone like Pro-Shift anyway..

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

[rgrigsby]

I friend of mine is running a blipping system on a Busa in a hill climb single seater, apparently they are quite fussy and you need to be completly off the throttle otherwise it doesn't work, having said all of that once you're used to it apparently it's fantastic.

 

Rob G

www.SpeedySeven.com

[dannylt]

My SPC straight cut type-9 with dogs was fine with 300bhp/225lbft and is probably the cheapest option! The noise is a bit annoying on the road though.

[Anthony]

Hi Danny, nice box 😬

Suspect that may be on the limit from discussions with g'box chaps :-)

[dannylt]

On the limit means perfect price/performance . I don't use wide rear slicks though, and the diff seems to be more marginal than the gearbox.

[Anthony]

Hi Danny,

 

The comments on the diff are interested, what sort of LSD are you using ?

[Alex Wong1697456877]

If I was going to fit another sequential, I'd go for the new Quaife (after a product settling 12 months) or maybe a drenth although I'd like to talk first hand with somebody who had experienced ownership first.

 

There's no doubt sequentials make for a more involving experience on track and especially on the down shifts when braking.

 

They are ok on the road but I prefer an H pattern box for a road car.

 

 

 

 

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[dannylt]

It's all subjective - I found the sequential quite uninvolving on track, though obviously quicker.

 

Anthony, it's a standard ZF plate diff.