Judd news

[bil588]

8-9 % more power with 3 % better fuel economy, right?


http://translate.google.com/translat...e.php?sid=3300

[PascaLM]

Interesting. Indeed, Henri Pescarolo says 8 to 9% more for the torque. He doesn't say if he considers it with the larger restrictors.

[bil588]

link?

[PascaLM]

Your link (Endurance-info).

[bil588]

i misread your first post. i thought you wrote that henri had said (last summer) 8-9 % more torque.

[knighty]

the figures I have heard about the new judd motor going from 5.0 to 5.5 are a 10% increase in torque, power is up 10bhp from 640 to 650bhp, and about 3% increase in fuel economy.......I think that translation has messed it up a tad.....the 5.5 makes more power at lower revs, reducing the revs with a larger capacity is the real benefit to the fuel economy.........

quite why its taken Judd to get to this point is beyond me.......the old 4.0 versions were great sprint engines, but not robust 24hr motors.......I think the exception is the dallara-lista 24hr win at daytona in 2001-ish with a 4.0 (i think?)...... but generally speaking the 4.0's were time bombs in 24 hr races..........high revs and prototypes generally dont get on.......yes I know peugeot and ferrari did it with success

I think its only a matter of time before judd do a 6.0 litre engine, probably with this 90 degree block for AIM industries & creation, then they might also be able to fully stress it, and really tidy up the engine installations, lose the A-frames, and the associated weight.......but it all depends if it can handle the torsional loadings of a prototype - which are notoriously severe.

[gwyllion]

The Pescarolo press kit for 2007 contains the following numbers for the new Judd engine:

• displacement: 5496 cc
• power: 640 hp at 7000 rpm (32.4 mm restrictors)
• torque: 670 Nm (67 mkg)

Last year the numbers were the following:

• displacement: 4997 cc
• power: 640 hp at 8500 rpm (32.7 mm restrictors)
• torque: 615 Nm (61.5 mkg)

So only an increase in torque of 10%, but no extra power. The reduction in revs is significant: 1500 rpm less to produce maximum power.

[Mirage M6]

and why new Judd 5.5 has less rpm than last year?

[gwyllion]

The air going into the engine is limited with the restrictor. So more displacement automatically means less revs. That is the whole idea of the rules: different engine configurations producing the same power.

[Mirage M6]

many thanks

[zac510]

Originally Posted by Mirage M6

and why new Judd 5.5 has less rpm than last year?

Probably maxes out the restrictors 'earlier'.

It'd be nice to know where that peak torque is but it overall sounds like a better engine: same power, more torque, better economy!

[JAG]

Originally Posted by gwyllion

The Pescarolo press kit for 2007 contains the following numbers for the new Judd engine:

• displacement: 5496 cc
• power: 640 hp at 7000 rpm (32.4 mm restrictors)
• torque: 670 Nm (67 mkg)

Last year the numbers were the following:

• displacement: 4997 cc
• power: 640 hp at 8500 rpm (32.7 mm restrictors)
• torque: 615 Nm (61.5 mkg)

So only an increase in torque of 10%, but no extra power. The reduction in revs is significant: 1500 rpm less to produce maximum power.

Seeing as the big handicap of the Judd, from what I've read, is the fact they always has to reduce revs for the race, and presunably top end power, hopefully the 5.5 can now run closer to it's qualifying pace.

[canam]

And it is generally viewed to be the best engine in the petrol class! I wonder where it will find the extra 100-150 bhp to equalise it to the diesels.

Watching the diesels go past a petrol P1 car on the straight was like watching a petrol P1 car go past a GT2 car. It doesn't take much engineering and driver expertise to pass on the straight...just crude bhp and torque. With enough power a garagiste with a **** chassis could pass a Judd engined P1 car. You don't need to be one of the world's major manufacturers.

Now visually aware of the gap between what are clearly two classes, it is far beyond a joke. It is just pure farce.

[JAG]

Not wishing to go off topic, but the diesels do have an advantage, I just doubt it's more than 80bhp, nevermind 150bhp.

Torque is something else altogether, and maybe offsett by weight and packaging issuse's, it's just a shame Le Mans is such a unique circuit that is ideal for diesel power.

I still firmly believe the best petrol P1 engine will be a turbo, which is why I'm suprised Judd's new motor will be N/A.

Andy Wallace stated the AER V8T came on leaps and bounds last season, I just wonder were that engine will be in 2008, with another winter of testing behind it, up against further restricted diesels.

[knighty]

I dont think the normally aspirated route is actually that bad.......although they dont have the torque figures of the turbo engines (I'm comparing petrol to petrol) they obviously dont need the intercoolers, and therefore the drag that gos with them......therefore a good big capacity petrol motor can be quite attractive from an aero point of view as it will feature a lot less drag.......this is an interesting point pointed out by Ulrich.......although the diesels have lots of torque, then need about 30% more cooling, as they run much much hotter than the petrol cars........

still a massive difference in performance between petrol to diesel though.......I'm surprised to hear its in top speed.......the last I heard in Henris whinge to the ACO, and some other track data, was in the Diesels superior acelleration, top speeds were supposedly quite comparable????

[canam]

I haven't been able to find any top speed numbers but they have not been particularly reliable in the past.

It has, however, been the case that the diesels run quite high levels of downforce because they can pull it on the straights. Top speeds can be a misleading indicator of power.

[jhansen]

Originally Posted by canam

Now visually aware of the gap between what are clearly two classes, it is far beyond a joke. It is just pure farce.

Le Mans 2004. The four R8s were split up a bit in qualifying. However, by the time they had reached the second chicanne on the mulsanne the four R8s were leading. By the end of the first lap they were leading by a decent gap. Visually, you could see the difference. And that was back during the "fair" rules. Diesel advantage or not, there is definitely an advantage between factory and privateer.

Given that, Judd keeps pushing forward, which is nice to see. It is a good alternative for privateers. Maybe the most accepted alternative.

[jhansen]

Originally Posted by knighty

I dont think the normally aspirated route is actually that bad.......although they dont have the torque figures of the turbo engines (I'm comparing petrol to petrol) they obviously dont need the intercoolers, and therefore the drag that gos with them......therefore a good big capacity petrol motor can be quite attractive from an aero point of view as it will feature a lot less drag.......this is an interesting point pointed out by Ulrich.......although the diesels have lots of torque, then need about 30% more cooling, as they run much much hotter than the petrol cars........

I still think turbo anything has an advantage over normally aspirated. The turbos have the pace in qualifying AND the race. Not to mention good economy.

[Adam43]

Depending on the rules (e.g. maximum displacement), yes. Although on a limited budget a N/A engine has the advantage of being simpler and a larger N/A engine will generally be more reliable than a turbo engine.

[bil588]

Originally Posted by JAG

I still firmly believe the best petrol P1 engine will be a turbo, which is why I'm suprised Judd's new motor will be N/A.

Andy Wallace stated the AER V8T came on leaps and bounds last season, I just wonder were that engine will be in 2008

An email from Alexander Frei:

http://www.alexanderfrei.ch/

The main objective in this wind tunnel testing-session is to improve the internal airflow of the car. This should help to lower temperatures from water- and air-coolers, which means a significant gain in engine-power.

another email:

Power should increase by about 40 hp. Around 650 hp is expected.

[bil588]

Originally Posted by gwyllion

The Pescarolo press kit for 2007 contains the following numbers for the new Judd engine:

• displacement: 5496 cc
• power: 640 hp at 7000 rpm (32.4 mm restrictors)
• torque: 670 Nm (67 mkg)

Last year the numbers were the following:

• displacement: 4997 cc
• power: 640 hp at 8500 rpm (32.7 mm restrictors)
• torque: 615 Nm (61.5 mkg)

So only an increase in torque of 10%, but no extra power. The reduction in revs is significant: 1500 rpm less to produce maximum power.

RfH says it has over 650 hp.

http://www.janlammers.com/engels/Xml...tem.xsl&id=424

[bil588]

RfH has a picture of their new Judd GV5.5 S2 motor

http://photos.janlammers.com/?catego...ery=5CDB5F7C01

[minimangler]

being from Rugby, just down the road from Judd, i do have a soft spot, but there is very little they can do in the face of factory competition AND favourable rules for said factories. When Pesca's car was in so much trouble and they were describing the scene on RLM i was a little sad
And however good or bad the engine in RFH's car was, it spent most of it's time garaged, did it not?

[knighty]

Just reading the may 07 issue of race engine technology magazine and found a snippet of info about the Judd-Ricardo Diesel LMP1 race engine……."Currently a Ford based 4 cylinder diesel engine is being used as a test engine for evaluation of the combustion systems, the race engine will have a 90mm bore mated to the crankshaft of the companies latest 5.5 Litre long stroke engine, the plan is to have the diesel V10 running late 2007"……..really now, how very interesting!........in doing this they seem to have released the bore and stoke of the 5.5, please forgive my excitement, as Judd are very coy about releasing technical info in my opinion, and I havent come across this before……..or someone please update me?

If the 90mm and 5 litre statement is true, by my calculations, that equates to a stroke of 78.5mm……which is VERY short stroke for a diesel, this makes me think they may achieve the power figures of around 700 bhp, but they will not achieve the high torque figures of 1100 to 1300Nm as per the Audi and Pug engines……this seems a very compromised design to me…….but I wish them the best of luck.

So now we know the stroke of the 5.5 at 78.5mm, I worked out the bore must be 94.4mm…….again, even for a gasoline normally aspirated restrictor engine, this seems a very compromised engine, whereby the bore is too big and the stroke is too short…….I dare say due to its roots as a big bore short stroke F1 engine…….just the opposite of whats required of a latter day sports endurance LMP1 restrictor engine, F3 engines are the best restrictor motors in my opinion, small bore, long stroke = loads of torque……..this seems to be reflected in the 5.5 torque figure of 670Nm……..by my sums, a decent normally aspirated big capacity LMP1 restrictor motor with 6 litres should be developing around or over 800Nm of torque……that would certainly reduce the gap to the diesels, but not fully close it!

I just thought I'd share my discovery / ramblings with fellow engine sados like me ;-)

[zac510]

Good spot knighty, but on the petrol engine, have you considered CoG in that mix? Modern sportscar engines mightn't be high revvers but they are strong on vehicle dynamics.