Page 1 of 8 12345678 LastLast
Results 1 to 30 of 214

Thread: straight line speeds at indy

  1. #1
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46

    straight line speeds at indy

    This went of topic from the "P.D.M sold" thread so i thought it more appropriate to move it to "Tech Talk"

    I will make a post soon.


    239.260

  2. #2
    Paradoxically Sublime Fool Turn13's Avatar
    Join Date
    Mar 2000
    Location
    Brownsburg, Indiana
    Posts
    32,427
    Blog Entries
    1
    Good I want to hear.... the rest of the story
    "Each day well lived makes every yesterday a dream of happiness and every tomorrow a vision of hope. Look well therefore to this one day for it, and it alone, is life"
    ~ Sanskrit poem attributed to Kalidasa, "Salutation to the Dawn"


    Brian's Wish

  3. #3
    SENÓR MODERATOR
    Join Date
    Feb 2001
    Location
    In constant turmoil......
    Posts
    17,976

    Re: straight line speeds at indy

    Originally posted by insider
    This went of topic from the "P.D.M sold" thread so i thought it more appropriate to move it to "Tech Talk"

    I will make a post soon.


    239.260

    Good...........then maybe we can lure IRLRACER out of hiding to tell us who was driving the gernade that he built.............
    SENÓR MODERATOR......

    "Better To Be Judged By Twelve Than Carried By Six"
    " Only Those Who Will Risk Going Too Far....Can Possibly Find Out How Far One Can Go "...T.S. Elliot....

  4. #4
    never was wannabe debdrake's Avatar
    Join Date
    Aug 2000
    Location
    too far gone
    Posts
    7,316
    I'm waiting....
    I'm from a place called the internet. Nothing disturbs me.

  5. #5
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46

    STRAIGHT LINE SPEEDS AT INDY

    If the chassis is working well, the average lap speed is between 4 and 6 mph lower than the average trap speeds entering turns 1 and 3.

    This is a very close "rule of thumb" which try's to take out the effect of the wind direction. Because of V2 (you will loose more speed heading into a head wind than you gain with a tail wind) this 2 mph window is close approximation)

    With the 1995 Menard motor (1050 observed h.p, i was at the dyno test) The trap speeds were in the region of 240 mph average of both ends of the track. This resulted in lap speeds of approx lap speeds of 234 mph for Scott and Arie. On pole day, these speeds where reduced by approx 3 mph becuse of the high dew point which killed the h.p. The Menard cars ran illegal boost that year, but that's another story.

    Arie's Cosworth in 1996 produced 950 observed hp at the legal boost limit, but because of the lower CD of the Reynard, a "healthy" pop off valve and chassis set-up, this resulted in a lap speed of 239 + mph lap speed.

    Arie's trap speed on that lap was 243 mph into turn 1 and 247 mph in to turn 3 (had a tow from robbie unser between T2 and T3), lowest speed in T3 was 237 mph!

    The Penske Ilmor/merc of 1994, reportedly had approx 1200 h.p with trap speeds in the 250 mph range. If the chassis was as good as the engine, this should have resulted in lap speeds of approx 244 mph. The qualifying speed was 228 mph.


    In my opinion the reason that Penske failed to qualify in 1995 was that the car did not have the h.p to make up for the chassis dificiencies which they should have noticed. The qualifying speed was 228 mph i.e, the speed split should have been around 5 m.ph and not 22 mph.

    When the 1995 Penske cars where fitted with "conventional" H.P, the rest is history.


    239.260

  6. #6
    Paradoxically Sublime Fool Turn13's Avatar
    Join Date
    Mar 2000
    Location
    Brownsburg, Indiana
    Posts
    32,427
    Blog Entries
    1

    Re: STRAIGHT LINE SPEEDS AT INDY

    Originally posted by insider
    ...because of the lower CD of the Reynard, a "healthy" pop off valve and chassis set-up, this resulted in a lap speed of 239 + mph lap speed.
    I wonder how much was the chassis and how much was the valve? 237 mph in the turns sounds like a pretty good chassis setup

    Originally posted by insider
    The Menard cars ran illegal boost that year, but that's another story.
    I love the way one good story leads to another
    Last edited by Turn13; 01-01-2004 at 10:27 AM.

  7. #7
    never was wannabe debdrake's Avatar
    Join Date
    Aug 2000
    Location
    too far gone
    Posts
    7,316
    Think what would have been if Penske had only had a decent chassis under that pushrod...

  8. #8
    Registered User
    Join Date
    Mar 2002
    Location
    OH
    Posts
    40
    Hey Tim,
    Great post. First thing tht caught my eye: The hp figures you quote here are considerably higher than were talked around at the time. How was Menard running illegal boost? Were they whistling the popoff valve?

  9. #9
    Registered User
    Join Date
    Sep 2002
    Location
    Indy
    Posts
    123
    I saw 247 straightline speed with a tow in 1996 by Tony Stewart and Scott Brayton. Quite possible Eddie did it too, but I don't remember. Don't think Mark Dismore or Danny Ongais quite got up there, but certainly well into the 240's. Also, just a remnder that Eddie Cheever ran a race lap of 236.103 in 1996
    Never saw a 250 speed at any point, but didn't they used to top 250 years ago, when they had super-powerful engines, but no handling?

  10. #10
    Long time pain N D arse
    Join Date
    Jul 2000
    Location
    North Carolina
    Posts
    9,429
    Sorry, but those HP numbers are all B.S.

    If any of those numbers were seen on a dyno, then someone was BIG TIME fudging the dyno.
    "IRL" ... what IS that anyway?

    J. Michael Ringham
    Vice President, Marketing
    IndyCar® Series Indy Pro Series

    www.jonescams.com yankeegoback.com

  11. #11
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46
    Cam king,

    The dyno at Menards was not "fudged" I did mention that they where using illigal boost. The boost limit that year for the stock block was 55". This 1050 hp figure was at 62" of boost. In the dyno room with me was Sonny and Butch Meyer.

    I am not aware of your credentials, if you are as familier with aerodynamics as you purport to be with h.p rateings you will note that the figure's i have quoted from past post's will coincide with reality.

    239.260

  12. #12
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46
    cam king,

    I should have said corrected not "observed" h.p.
    I also think that the reported 1200 hp of the Ilmor was high as well. 1100 corrected hp is closer.

    Happy new year.


    239.260

  13. #13
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46
    wall magnet,

    Eddie always reminds Arie that he has the only indy record that Arie doe's not have.

    In 1996,Arie was crusing around in 2nd place untill Salaza ran into him leaving the pits. If not for that incident, who know's. I had geared Arie to run 238+.

    Don't know about about the earlier years, before my time. I don't think that anyone approached 250 mph because they could not carry enough speed off T2 and T4 to reach that velocity.

    I may be wrong.

    Happy new year.

    239.260

  14. #14
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46

    1995 menard boost

    Hi Bill,

    In 1995 we tested at the speedway with Arie and Scott for about 25 days before opening day. We tested in the cold, the heat and the wind.

    Arie would run 232 mph laps in a 40 mph, gusting to 55 mph wind when Emmo, Rahal and Al jr could not clear 205 m.ph. Emmo complained to Arie that Rodger Penske hade told him to continue to test because "if Arie can do it, so can you"

    But, we had not tested in the rain. During qualifying That year i had mist falling on my face. Contrary to popular believe, air density doe's not increase with humidity ( I spoke with professor Havey at Imperial Collage in London about this urban legend) If i had rememberd my "steam tables" i would have realised this for myself. But as water vapor displaces oxygen atoms, the effect on engine performace is greater than the reduced air density and drag.

    We had discovered in testing ( a mechanic messed up the waste gates) that you could over boost the 55" valve by producing more air flow than the pop off valve could bypass. This is "old hat" and has been done in the past. As far as i was concerned this was legal as we used a legal pop off valve and just had to compensate the fuel map for when the valve opened.

    The "popoff" valve in 1995 had two basic funtions. #1, to open at a preset limit (for the Buick, this was 55") and then #2 to control the amount of air flow bypassed when the valve was opened.

    At this point i concentrated on the chassis setup for Arie and Scott as I had seen 1050 (corrected) hp at 62" of boost on the dyno. and anymore than this, the law of diminishing returns would set in as the exhaust back pressure would exced the boost pressure.

    I had not realised untill the following year that U.S.A.C had spotted what was going on and increased the amount of bypass on the valve to stop over boosting. In responce, the team manager some how found a U.S.A.C seal gun and locked both Arie's and Scot's valve's solid for qualifying and then had them resealed.

    Before qualifying, the team manager (Larry curry) held a meeting with Arie,Scott and myself and insructed than we use no more than 60" for qualifying. Uptill that time, Arie had always been a little faster than Scott in practice.

    Arie went out to qualify first and as ordered dialed the boost in to 60". Before Scott qualified, Larry reached into the cockpit and cranked in 2" more boost. I found out later that Larry and Scott had a deal to split the pole money. After reviewing the data, especially the boost trace (i still have this data) Arie was a little upset.

    At post qualifying tech inspection, both valve's where found to be illegal and U.S.A.C. requested that both cars be disqualified. The powers that be decided to let Menard keep the pole but fine them for tampering with the pop off valve. The fine that year for that offence was $8000, this was raised to $80,000 for 1996.

    Neither, Scott, Arie or myself where aware of the illegalities, we just thought we where over boosting the valve.

    The pay back was that U.S.A.C gave team Menard, 50" valves for the race. Larry Curry was bitching and moaning about a bad valve in the race (Arie still finished on the lead lap) The tech head from U.S.A.C (hi Mike, hope you read this) Asked Curry if we could please stop f**king each other.

    Mike made sure that this situation did not occure in 1996 when Arie set all the records, but there again is an other story.


    239.260

  15. #15
    Long time pain N D arse
    Join Date
    Jul 2000
    Location
    North Carolina
    Posts
    9,429
    Originally posted by insider
    Cam king,

    I am not aware of your credentials,
    I designed the camshafts they ran in the Menard engine you watched on the dyno.

    That engine could not make that much HP, it is impossible.

    Here is how you can calculate 100% volumetric efficiancy.

    CID x RPM x Compression Ratio x 14.697 / 792,000 x (inches of boost / 29.92) = Max HP

    You can add anouther 3-6% for the methonal, but that's all you'll get.

    I think Butch and Sonny were giving you the engineer treatment.

  16. #16
    Long time pain N D arse
    Join Date
    Jul 2000
    Location
    North Carolina
    Posts
    9,429

    Re: 1995 menard boost

    Originally posted by insider
    H
    The pay back was that U.S.A.C gave team Menard, 50" valves for the race. Larry Curry was bitching and moaning about a bad valve in the race (Arie still finished on the lead lap) The tech head from U.S.A.C (hi Mike, hope you read this) Asked Curry if we could please stop f**king each other.
    This is one reason why I've soured on Indy racing.

    I hope Mr. D....... can live with the fact that he took away scotty's best chance at winning the 500.

    And I'm sure there was a lot more to it than payback for qualifying. The IRL needed more then a few Buicks to get off the ground in 1996, and if Menard ran away with the 95 Indy, it would have been hard for the IRL to get any other engine manufacturer to help them out.

  17. #17
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46
    Camking,

    I just tried you H.P formula, but it made no sense. I also note there is no temperature compensation. Would you like to make a post using real numbers ?, I am always happy to be enlightened.
    Are you aware of the RPM used that year?

    The !995 Menard Lola had a drag coefficent of 0.56 (in qualifying trim) with a frontal area of 17.55 sq ft. (approx 1000 lbs of drag at 200 m.p.h) and would need 1020 h.p at the wheels to achive a speed of 246 mph. This is in a perfect world of 60 deg F and zero % humidity and with no rolling resistance. ( i do not know of any car or engine that works in this environment) So the h.p figures i have quoted would appear to be close unless the wind tunnel and dyno where both off in the same diretion.

    Please remember there are 3 types of lies. lies, dammed lies and statistics. You can now add to that list, engine dyno's and wind tunnels. But when they both give you the same answers, you tend to believe them.

    Sonney and Butch would not try and mislead me. We where pretty tight. I had solved a fuel pressure problem for them and calculated and designed waste gate springs in 2" steps to run boost from 56" to 66" as they didn't know how to. I spent a lot of time with them in the dyno room and so they knew i was "hip" on the engine front all well.

    Never thought about the Buick political situation for 1996. I really don't think anyone had the foresight to consider this as they where to busy with the upcomeing split. But I could be wrong.

    Mr D......... had no axe to grind with Scotty and was as fond of him as we all where. But he did have a problem with L.C and his constant cheating. It would appear to me that L.C's primary objective was to show that he was smarter than the tech officials.

    It was not Mr D......... that cost Scot and Arie that year. What would i have done in Mr D.........'s position, I don't know, i could see both positions, but i only found out the following April what really happened.

    Let's keep this thead going, especially on the technical front.

    I look forward to your next post.

    Regards,

    239.260

  18. #18
    Registered User
    Join Date
    Mar 2002
    Location
    OH
    Posts
    40
    Originally posted by CamKing
    I designed the camshafts they ran in the Menard engine you watched on the dyno.

    That engine could not make that much HP, it is impossible.

    Here is how you can calculate 100% volumetric efficiancy.

    CID x RPM x Compression Ratio x 14.697 / 792,000 x (inches of boost / 29.92) = Max HP

    You can add anouther 3-6% for the methonal, but that's all you'll get.

    I think Butch and Sonny were giving you the engineer treatment.
    Not questioning your credentials or facts in the least; just have some questions. With 62" Hg manifold pressure, I think we can assume considerably greater than 100% volumetric efficiency, so I am not quite following your formula. While I recognize some of the elements I couldn't get it to make sense. Could you elaborate upon what it finds and how it is derived?

    1050 hp from 209 CID equates to just over 400 PSI BMEP, which is a lot but well within the realm of the possible. According to most sources, the Ilmor pushrod engine achieved a little better this with 7" Hg less MAP. The four-cyl. BMW 1.5 liter F1 turbo apparently developed over 1000 PSI BMEP, while the Offy turbo was good for nearly 500 PSI, antique though it was. I am a little skeptical of the 1050 hp figure myself, as this is the first I've heard it...although this is also the first I heard they were running 62" of manifold pressure. That is 13% more pressure than 55" Hg, and a commensurate power gain is not entirely unreasonable. 935 hp + 13% is 1056 hp.

  19. #19
    Long time pain N D arse
    Join Date
    Jul 2000
    Location
    North Carolina
    Posts
    9,429
    the 100% volumetric efficiancy is calculated for the boost pressure.

    209 x 9,200 x 11 x 14.697 / 792,000 = 392.49155

    392.49155 x (62/29.92) = 813.318 HP

    This is calculated for 60F @ sea level.

    I don't have the exact RPM or Compression ratio in front of me, but when I get to work I'll look them up. I also need to look up the Stroke so I can calculate RPM( I know what the cam duration was, so with the stroke I can tell you were it made peak power.

    These numbers do not add anything for "frictional Loss factors" because there I don't believe in fiction. The power coming off the end of the crank is the only thing that counts.

    BTW, if you want to compare the buick to the offy, the offy had to run 110"boost with 20% nitro to make over 1,000hp

  20. #20
    Registered User
    Join Date
    Aug 2002
    Location
    Denver, CO
    Posts
    600
    Are you sure about those drag numbers? Your frontal area and Cd give a drag of 1055lbs @ 200mph. I had a drag figure of ~850lbs @ 200mph for the 95 Reynard. I know the Menard had that big hump which must have added something (and it was a Lola). Even if we say it had 900lbs drag, that means you need only about 890hp to get to 246mph. 1050hp would give you a top speed of 260mph. This calculation, of course, is for "terminal" velocity, and assumes you have an infinitely long straightaway with which to get up to speed.

    Incidentally, when I plug 2800lbs of downforce, 900lbs drag, and 890hp into my sim program, I get a lap speed of 239.9.

    I know the Imperial College tunnel, at least, greatly overreported drag numbers (by almost 10%) compared to the actual car. I always assumed this was something to do with Reynolds number effects from running a scale model at slow speeds. I don't know if Southampton demonstrates the same phenomenon (or to the same degree), but it's one reason I wasn't too worried about the Falcon tunnel data.

    The problem with both wind tunnels and dynos is the operators are always throwing "correction factors" onto the output, so you never know where you really are, especially when you compare the results from different facilities.

    Originally posted by insider
    The !995 Menard Lola had a drag coefficent of 0.56 (in qualifying trim) with a frontal area of 17.55 sq ft. (approx 1000 lbs of drag at 200 m.p.h) and would need 1020 h.p at the wheels to achive a speed of 246 mph.

  21. #21
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46
    camking, bill and scott.

    The Lola model was tested in a closed jet tunnel in 1995 with Mike Clark. The Reynard was tested in an open jet tunnel at cranfield the following year with Andy Mac, the Reynard showed a drag reduction of approx 80 lbs at 200 m.p.h, Tunnel, model, reality or the phase of the moon, i did not know which caused this but these where the numbers i had to work with.

    Please correct me if i am wrong, but i believe the The c.i.d for the stock block in 1995 was 255". this number rings a bell.

    In camkings equation, it shows 9,300 rpm. The "flash' reading of 1050 h.p was at 9,700. Sonny did not want to exceed 9,500 on the dyno for fear of the engine exploding and we where protected by 2" thick plexiglass.

    When this engine was fitted to Arie's car, L.C pointed to Arie and told him "run this baby at 10 thousand and 64"!" I don't know if the engine produced more or less h.p at these revs as we where in uncharted waters. I was somewhat concerned for Arie's safety. The engine let go on the front straight on his 3rd time by.

    Scotts sim would appeare to be fairly accurate when you take into account all the factors involved. (which sim do you use Scott?)

    Let's keep this going guy's, this is an education and enlightenment for all of us.

    Regards,

    239.260

  22. #22
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46
    Hi scott,

    I understand that imperial collage has now installed boundary layer bleeds on the walls of the working section to give more accurate drag results. With out getting to technical, it was always a little cramped in there. (that's why i like open jet tunnels, you don't hit your head on the roof when you stand up in the working section!)

    Remember, lies, dammed lies, statistics and now wind tunnels and engine dyno's.

    regards,

    Tim

  23. #23
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46
    camking,scott and bill.

    Sorry guys, 255 was the weight of a girl i was dateing that year she must have made quite an impression on me. (it still hurts)


    239.260

  24. #24
    Registered User Novi-'s Avatar
    Join Date
    Apr 2001
    Location
    Wal-Mart Oh
    Posts
    2,318
    ? Can peek HP/torq be moved up/down, within a given range that's probly dictated by cam profile, by final gear ratio, or on a dyno by how much water you run it against?
    "Free your mind and your ass will follow"

  25. #25
    Registered User
    Join Date
    Sep 2002
    Location
    Indy
    Posts
    123
    At the start of May in 1996, Team Menard opened its doors to a number of journalists, and gave them 'the tour'. There was an engine on the dyno at the time, so Butch cranked it up for them, and took it to 1000HP. I wasn't in the dyno room, so I don't know what boost or revs he used, but there were plenty of witnesses. We were using over 10,000 max RPM by that stage (although again, I don't know if that was best power), and I would guess the boost was 60".

  26. #26
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46
    wall magnet

    If i remember correctly, U.S.A.C raised the legal boost from 55" in 1995 to 60" in 1996 for the stock block. After the antics with the valve's in 1995 i was surprised they would do this.

    I believe the larger picture was to try and keep the Buick competitive for 1996. I remember Johnathan Byrd being upset at me because Arie had tested 2 m.p.h (235) faster than the Menard Buicks, just as he was lobbying for the original 55" boost limit for the stock blocks.

    I did hear that the 1996 Menard Buicks could rev up to 10,300 rpm


    239.260

  27. #27
    Insider
    Join Date
    Sep 2000
    Location
    somewhere west of normal
    Posts
    3,487
    I only understand about every 4th word, but this is a darn interesting thread...

  28. #28
    Registered User
    Join Date
    Aug 2003
    Location
    indianapolis
    Posts
    46
    micki,

    sorry, i'm English.

    239.260

  29. #29
    Insider
    Join Date
    Sep 2000
    Location
    somewhere west of normal
    Posts
    3,487
    No, that's not it....I'm a chic...

  30. #30
    SENÓR MODERATOR
    Join Date
    Feb 2001
    Location
    In constant turmoil......
    Posts
    17,976
    Originally posted by Micki
    No, that's not it....I'm a chic...


    insider is a "chick magnet"................

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •