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18 Sep 2007, 19:18 (Ref:2017283) | #26 | ||
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yeah, interesting point, but nowdays its not a problem, as cylinder heads can be designed VERY light to recoup the C of G gain given away by the long stroke......... the Cosworth F1 heads are a classic example, nothing high tech, just a new approach......if the crank stroke was to increase from say the current Judd 5.5Litre 78.5mm......I think it needs to be in the region of around 90mm.....this is only a radial increase of 5.75mm......which in an F1 car is very significant......but in an LMP1 car thats not worth worrying about in my opinion......the Pug and Audi diesel motors will be around that figure in stroke, so its already been done........and proven to work
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18 Sep 2007, 19:24 (Ref:2017295) | #27 | |
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I presume the new AIM motor would be more in keeping with the 'ideal' bore / stroke ratio ?
Regarding your quote on F3 motors providing the best starting point....is that why the Zytek is so good ? |
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18 Sep 2007, 20:18 (Ref:2017375) | #28 | ||
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18 Sep 2007, 20:41 (Ref:2017396) | #29 | |||
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18 Sep 2007, 20:50 (Ref:2017405) | #30 | |
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oopps meant F3000 That is where they started making engines!!
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18 Sep 2007, 21:39 (Ref:2017453) | #31 | |||
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18 Sep 2007, 21:39 (Ref:2017454) | #32 | ||
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If I remember correctly, Judd built the F3000 engines, but Zytek were the ones tasked with maintaining them over the years.
And yes, the original Judd KV F3000 engine is the basis for the current A1 GP engine. However, I don't believe the "Z" series of sportscar engines are based on the Judd KV. |
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18 Sep 2007, 23:24 (Ref:2017494) | #33 | ||
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I dont know much about the AIM motor, only that its 90degrees and V10!
just to state my thoughts on the LMP1 4 litre Zytec, and 3.4 LMP2 Litre Zytec/Judd/Porsche/Acura sports car engines.........they are sprint engines, not true 24hr engines........have seen it all before, wind the revs up for qualifying and set a blistering pace and qualify well, but come the race, turn the revs down, and its anyones guess how many will actualy hang together till the finish, but enough do, Porsche and Acura really do seem to have their reliability sorted. the 3.4 LMP2 engines are doing well in the ALMS, especially with the nature of their circuit layouts (short) which allows them to shine compared to the Judd V10's and diesels........cant wait to see them at LeMans as for the 4.0 LMP1 Zytek.....again, its a good sprint engine, but they seem to be bettered by the 5.5 gas Judds and 5.0 turbo-diesel audi/pugs on the big circuits, the superior torque of the bigger engines really come into play. to go 24hr sports car endurance racing with a big capacity (4 litre and upwards) flat plane V8 without balancer shafts is ludicrous in my book.......I recently read an great article about the Ford DFV V8 powered gulf-mirage that won leMans with Derek Bell in the 70's, the first time he drove the car he vomited in his crash helmet, as the DVF rattled so much it was unbarable, and it was a miracle they won LeMans, as the engine had broke loads of chassis parts and an engine mount, and the car was all only hanging together by the barest minimum at the finish. even back in the 70s Cosworth had a 4.0 version of the DFV planned and it had twin lanchester balance shafts to balance out the nasty shaking motion of the flat plane crank, but it was scrapped as Keith was only interested in F1 yes the 4.0 Zytek is a light engine, but thats not the order of the day for 24hrs, durability is.......last I heard is Zytek are keen to exploit electric hybrid technology with their 4.0 V8, as by their own admission it cannot compete on torque terms with the bigger engines........the electric hybrid will fill in the extra punch of torque they require........but even saying that, electric hybrid is not the way forward for motorsport, it will be either compressed air, hydraulic of flywheel type hybrids........I'm not an expert on hybrids, but I know people who very much are, and they are advising two top F1 teams, and I believe what they say. apologies if I sound like I'm slagging off Zytek, I dont mean to, these are just my opinions based on my race engine design knowledge, its obviously a very fast car! as is the Porsche and Acura what I'm trying to say is I dont beieve anyone has yet made the ideal fully stressed (chassis member) 650bhp 800Nm normally aspirated LMP1 24hr race engine that ......to me.......seems so easily possible within the regs, all the current normally aspirated LMP1 engines just appear to be compromised designs it very big ways Last edited by knighty; 18 Sep 2007 at 23:33. |
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19 Sep 2007, 04:47 (Ref:2017581) | #34 | |||
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7 Oct 2007, 04:34 (Ref:2033445) | #35 | |
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Judd's all-new low-friction "DB" 3.4 liter V-8
http://www.engdev.com/ http://motorsport.com/news/article.asp?ID=268968 http://www.projectlemans.de/images/s..._lmp2_copy.jpg |
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7 Oct 2007, 11:58 (Ref:2033853) | #36 | ||
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Zytek sprint engines? Ever heard of the Le Mans 24 Hours? Check their performance there in the last couple of years, e.g. which were the engines of the only finishers in 2007
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7 Oct 2007, 17:47 (Ref:2034169) | #37 | |
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Why do they call it 'DB'? (engine for an Aston Martin LMP? )
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7 Oct 2007, 18:56 (Ref:2034231) | #38 | |||
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LMP2 2007 was a race of attrition......they were the only two finishers......I have read all the blurb on the zytek website boasting about the 2007 result.......its tounge-in-cheek to say the least.......it seems both LMP2 engine routes (4cyl turbo and V8) are too highly strung for 24hr racing.
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7 Oct 2007, 19:55 (Ref:2034269) | #39 | ||
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now we're talking!
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7 Oct 2007, 20:40 (Ref:2034317) | #40 | ||
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The Mazda MZR-R hasn't competed in a 24 hour race yet. |
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8 Oct 2007, 09:34 (Ref:2034777) | #41 | ||
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how about ROC's 5th place finish a few years before with the VW-Lehman 4cyl turbo in the Reynard........I agree LMP2 cars can finish 24hr races......but the attrition rate is always very high.......
even for a privateer, I think going LMP1 is probably more cost effective in terms of engine life.......the LMP2 motors are VERY highly strung.......whereas 5.5 Judd producing 650bhp at 7000rpm is near road-car engine speeds and reliability.......the big Judd LMP1 motors now really seem to have cracked the relaibility nut.......the old 4 Litre LMP1 motor was the complete opposite |
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8 Oct 2007, 10:35 (Ref:2034831) | #42 | |||
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6 Nov 2007, 16:07 (Ref:2061290) | #43 | ||
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Just received this months copy of race engine magazine and there is some interesting tech news on Judd.....for engine sados like me
LMP2 DB V8 (XV replacement)…..new motor 3.4DB is progressing well, 5kg lighter, 8mm shorter, ditching the slide throttles, and now using barrel throttles, I dare say this is more reliability related than performance related, as I know both systems produce equal power results.......aparrently this is why embassy went to Zytek - did they have slide throttle issues?.......anyway, bore increased from 92 to 94mm (now same as GV5.5 V10), therefore a reduced stroke of 61.25mm (from 62.5mm)……smaller bearing journals, taller deck height, longer rods, for reduced piston side loading, therefore reduced friction…….I think this latter point is a big hint that Judd know the LMP2 4 litre rules are coming, hence all they will do is fit a longer stroke crank, with shorter rods, hey presto, a 4 litre LMP2 LMP1 90 degree AIM V10……. the AIM mob sound very comitted, they employ about 500 people, and are a big Japaneseautomotive engineering consultancy firm doing a lot of work for Toyota, I think a bit like Ricardo…….. the first engine will be a tad compromised due to lack of time, they are staying with 5.5 Litres and using as much of the base engine as possible due to a restricted time scale…….in 2008, a further revised block will be produced to gain 6 litres in capacity, so I'm guessing this will be available for the 2009 season, my educated guess is this will make the engine rev lower, reduce friction therefore improve fuel economy by about 2%, and produce more power (10bhp?) ……..and more torque (10%?)…..the AIM engine will be exclusive to creation in 2008, the project will run for 3 years, something special planned for 2010……perhaps direct injection or diesel……design work is being done by Hiroyuki Kaneda, who works for "Enginus" who are an engine off-shoot of AIM, he did the Zytek motor, and I think he is ex Honda-F1…….best of luck! Last edited by knighty; 6 Nov 2007 at 16:16. |
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6 Nov 2007, 19:41 (Ref:2061442) | #44 | ||
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Sounds very encouraging. AIM certainly sound a lot more serious than I had previously imagined.
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6 Nov 2007, 20:08 (Ref:2061465) | #45 | ||
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7 Nov 2007, 07:33 (Ref:2061826) | #46 | ||
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According to Judd the barrel throttle (instead of butterfly throttle of old XV engine) should achieve better part-throttle control. The main goal seems to achieve higher revs. Judd believes that current LMP2 air restrictor size allows engines to run up to 10500 - 10800 rpm. The current XV engine can not achieve this consistently; the shift points of the XV are at 10300 rpm, while the Porsche MR6 V8 is believed to run at 10500 rpm. They want to go up to 10800 rpm for the new DB engine. The first dyno test will be late January 2008. The current task is to finalise the crankshaft details. This is more critical for a high revving V8 because of vibrations. |
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7 Nov 2007, 09:09 (Ref:2061876) | #47 | ||
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[QUOTE=gwyllion]The latest issue of Racecar Engineering has similar news (DB V8 sharing lots with GV5.5 V10), only less technical details.
According to Judd the barrel throttle (instead of butterfly throttle of old XV engine) should achieve better part-throttle control. QUOTE] thats right, they are saying the DB will be the little brother of the current 5.5 V10 GV motor, it will share the same bore, and included valve angle of 14 degrees.......thats the smallest I have ever heard of, last IRL motor I worked on was 18 degrees and that was considered F1 spec narrow at the time in 2003 ish, anyway. the heads will be compact , so although the deck height of the DB is taller, the overall engine height is no worse than the XV. Interesting they say that about barrel throttles........by my experience, and the general race engine design world consensus, this is the complete opposite, butterfly throttles offer the best mid-range control, and barrel throttles are the worst for mid range......barrel throttles are also very heavy compared to butterflys.......barrel throttles were a fashion for a few years, but many F1 teams have reverted to butterflys......Renault for sure. But people do still use em! interesting about the Porsche revs, personally I'm not a fan of high revving endurance engines, it causes all sorts of other nasty issues like bad fuel economy, chassis vibrations and a lack of engine durability Bently 03.......dont thank me, thank race engine magazine, I have just subscribed to 2 years worth (8 per year) for £120 and bought 3 back issues.......believe me, well worth the money! |
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7 Nov 2007, 10:18 (Ref:2061946) | #48 | ||
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9 Nov 2007, 11:54 (Ref:2063684) | #49 | |||
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5 Dec 2007, 13:32 (Ref:2082114) | #50 | ||
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did anyone read John Judds thoughts on next years new gasoline fuel..........it will be Shell E10, which is 10% Ethanol, which he eslimates, that combined with the restrictor increase, teams will lose 1 lap at lemans!!!!....so from 13 to 12 laps.......as you need more volume of ethanol to reach the same equivalent of gasoline, in otherwords, its not as dense as gasoline for a given volume, which is exactly what Nasamax found out a few years back, I dont think this is a real surprise to be honest.
but I bet this will not go down well with all gasoline engine runners......I think all the supposed "gains" handed to gasoline engined cars are a load of red herrings 900Kg weight is common to diesel the restrictor increase will badly hit fuel economy, although give about 20bhp The E10 fuel is not as dense as normal gasoline, so bad for fuel economy. not good me thinks |
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