Does Audi/Peugeot/Toyota use XTrac's IGS?

[Félix]

IGS is Instantaneous gearshift. More info here (http://3d-car-shows.com/2011/xtrac-i...ovation-award/) and in the March issue of Racecar Engineering magazine. It's basically a way to achieve seamless gearshift like in F1 but without resorting to double clutch (forbidden I know), double selector barrel or fancy electronics.

The article in RCE says it's as simple as sliding a standard gear cluster out and sliding in an IGS cluster. Only manufacturers use it since there is a lot of expensive "recalibration" to do. So, do/did the sportscar manufacturers use it? It's hard to tell from the outside with quiet diesels but I thought some insiders (knighty?) might know.

Gains are reported to be substantial and would probably add up to SECONDS around LM. And it sounds like the shifts are quite soft on the transmission (smaller torque spikes than standard?!), which is making me believe it might be suitable for endurance racing. It seems Honda recently found 1 second a lap through shifting in Moto GP and rumour say it's the reason.

[chernaudi]

Out of the three, I think that maybe only Audi could (though probably not) have used/is using IGS (and that's a big maybe because the R18's gear shifts didn't sound any faster than the R15's or the R10's, or even the R8's), and that's only based on the fact that Audi uses XTrac gearbox internals on the R18, as well as the R10 and R15 (the R8 used Ricardo internals). I do doubt it for last year's R18, but it could (or maybe not) be used on the 2012 cars.

As for Peugeot and Toyota, there's been some conflicting info--RCE said that the 908 last year used an XTrac gearbox, but I've read from other sources that they stuck with Ricardo, and Toyota/TMG supposedly are using a gearbox built by Toyota Motorsport GmbH themselves. The conflict here is that the GT-One was variously described as using a TMG/TTE gearbox, or a TTE(TMG)/XTrac gearbox. So TMG might be having another company build the internals to their specs like Audi did with Ricardo and have done/still do with XTrac.

Usually, the factory teams (or better off or more enterprising private teams on occasion) design their own gearbox casings and buy internals off of XTrac, Ricardo, etc built to their specs.

But as to IGS, I don't think any of the factory teams used it this year, and if there are some reliability concerns with it, I doubt that Audi or Toyota will use it this year, certainly not at LM. Granted, the R18 and the TS030 have seemless gear shifts, but so did the older diesels, which we know probably didn't use IGS. It's a bit of a guess, but I'm guessing not for right now.

[TF110]

Toyota make their own transmission. Not sure if it's seamless shift. But they did have something similar in F1 so I wouldn't be surprised. They might have taken this from Williams when Nakajima was there. Or so it was rumored.

[chernaudi]

I've heard of various schemes for seamless shifts in F1 cars, such as twin clutch gearboxes (not entirely practical and probably illegal now), dual shifting barrels, and even pre-selector gearboxes (modernization of an old technology from the 1930s with the old Wilson pre-selector gearbox). About anything that could be considered legal under the rules that it can't be a fully automatic or CVT gearbox.

In sportscar racing, the rules on gearboxes do have more limits but as long as it's a 5-6 speed manual with seq. stick, H-pattern, or paddle operated shifting, that's the basic requirement, and I don't see how the IGS would be illegal (though DSG and probably the pre-slector stuff is). However, I don't see Audi or Toyota using that right now, even if they've tested it and know about it. Later on, possibly, but this early in the development of their new cars, I'd have to rate that as a bit improbable.

[gwyllion]

For people who have not read it, the RCE article is available at http://gb.zinio.com/reader.jsp?issn=...096&o=ext&p=55.

Apparently the IGS system is used by "several customers, all in top-level professional motorsport". When I read the article, I immediately thought that Audi and/or Peugeot were using this system. I can imagine that this could also be used by GTE teams.

Le Mans is all about fast acceleration, so this technology is a perfect match. From the RCE article:

On a 250 m straight it is worth around 3 km/h and allows gearchanges to be made 10 m earlier. Obviously, the benefit is track and series dependent, but Roper finds its typically worth about three tenths a lap.

On the long Le Mans lap, a gain of more than 1 second indeed seems plausible.

[gustavobamba]

Could Porsche been using "IGS system" for the 2014 LMP1??

They will do race testing in 2013 (at least is a solid rumor) so the new set of rules should be almost ready. they will have plenty of oportunities to develop a winning race machine out of the box.

[gwyllion]

Okay, I just checked the LMP1 rule book.

9.2 Gearbox
9.2.1 Maximum 6 forward speeds.
9.2.2 Electronic or electric management and selection devices, and semi-automatic or automatic transmissions are not permitted.
Any system that permits more than one gear pair to be engaged to the drivetrain at any one time is prohibited.
Gear change: gearshifts have to be distinct sequential actions where the extraction of the actual gear engagement is subsequently followed by an insertion of the target gear engagement.

9.5 Clutch
Only one clutch is authorised for the combustion engine.
The only energy which can operate the clutch is the one provided by the driver. This one must exert with its foot all the pressure necessary to operate and control the mechanism of the clutch.

I guess that the IGS system is legal under the LMP1 rules.

[gwyllion]

Originally Posted by gustavobamba

Could Porsche been using "IGS system" for the 2014 LMP1??

According to the minutes from the TWG meeting of June 30th, 2010 (see here), there was a proposal to make the transmission completely free in the 2014 LMP1 rules. If that is the case, more fancy things (e.g., CVT) can be done instead of the Xtrac IGS solution.

[chernaudi]

This also brings up a point, too. The Porsche GT cars use a beefed up Porsche manual transaxle with a SMG shifting mechanism on it.

For the RS Spyder, at least in '07 and '08, Porsche was listed as a XTrac customer as far as gearbox internals. Those of us around back then know that the gearbox was a weakness of the '06 RS Spyder, and that at the time at least Porsche claimed to have designed and built it's gearbox. Could Porsche switching to XTrac after '06 for the Spyder be due to their own gearbox problems, or standardization among the VAG companies' racing programs--Audi switched to XTrac on the R10 in '05 before it set out on track.

Of course, we don't know if the proposal for LMP1 gearboxes to become open will happen or what it will mean in the overall scope, but that could mean things like DSG, CVTs, and for sure IGS (which seems to be legal now, too) will be allowed if that rule is passed.

Strangely, Porsche ran some DSG gearboxes in their factory 962C's in 1985, but they never used them in endurance races because there was a risk of the twin clutches coming out of adjustment after much more than 1000kms.

[gwyllion]

The Porsche RS Spyder could not have used the Xtrac IGS solution, because it was not yet developed

When the IGS solution was presented at the 2010 CTI Transmission Symposium in December 2010, Xtrac said that the system had been track tested for 2 years. That means that it was first raced in 2009, so after the Porsche works LMP2 campaign.

Furthermore, according to http://auto-racing.speedtv.com/artic...he-spyder1/P4/ Xtrac only provided the limited slip differential of the RS Spyder.

Coincidence or not but 2009 is the debut of the Audi R15

[gwyllion]

Originally Posted by chernaudi

I do doubt it for last year's R18, but it could (or maybe not) be used on the 2012 cars.

The R18 also use an Xtrac gearbox, like the R10 and R15.

Originally Posted by chernaudi

As for Peugeot and Toyota, there's been some conflicting info--RCE said that the 908 last year used an XTrac gearbox, but I've read from other sources that they stuck with Ricardo, and Toyota/TMG supposedly are using a gearbox built by Toyota Motorsport GmbH themselves.

Peugeot never used an Xtrac gearbox. This site lists the championships in 2011 that were won with an Xtrac gearbox:

Le Mans 24 Hours – 1st, 7th, 9th, 10th (Overall)
Le Mans 24 Hours LMP1 - 1st, 7th

The new 908s were 2nd, 3th and 4th and the grandfathered 908 was 5th in 2011.

I expect that the TS030 gearbox (casing + internals) is completely by Toyota.

[Félix]

I was sure that Peugeot had worked with Xtrac, but it appears that it was a Ricardo box in both the old and new versions.

Could the Zeroshift mechanism used in F1 be suitable for endurance racing then for Toyota and Peugeot?