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Menard and pop-off valves?


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#1 Victor_RO

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Posted 26 September 2014 - 09:18

After reading Jade's book about the Ilmor 265E and the story about the pop-off valves during that year, I was reminded of some allegations I read somewhere (can't remember where) about Menard tampering with pop-off valves the following year and using illegal valves to secure the pole-position for the '95 500. Does anyone know any more details about this story and what actually happened?



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#2 Magoo

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Posted 27 September 2014 - 14:48

In the turbo era, there are different pop-off valve tales for every year at the Speedway and it's easy to get them mixed up. 1995 was the year that the Menard team complained it was dealt some bad popoff valves -- calibrated too low, or at least inconsistent. 

 

It also helps to keep in mind that in terms of gossip, a racing paddock is worse than a church ladies' sewing circle, and any stories should be taken with a big grain of salt. 


Edited by Magoo, 27 September 2014 - 14:52.


#3 Ross Stonefeld

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Posted 27 September 2014 - 14:57

Tim Wardrop used to post on Trackforum, or at least someone claiming to be him(to give us some argument flexibility). He's no longer with us but I think we can consider it safely public domain?

 

http://www.trackforu...s-at-indy?pp=20

 

Under the name "insider (aka 239.26)"

 

 

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.

 

That's just on the first page and I'm reading the rest now. I saved it at the time because we have somewhere here who's run an Indycar during that time period and might find the comments interesting, infuriating, or just downright ridiculous; but I never bothered because I figured he's a professional and wouldn't dabble with such things. But I saved the link(even with a computer move) just in case...


Edited by Ross Stonefeld, 27 September 2014 - 14:58.


#4 Magoo

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Posted 27 September 2014 - 18:01

That is indeed Tim Wardrop. RIP Tim. 

 

 

Like I say, you may want to take these stories with a grain of salt. Even among people who were directly involved, there is serious disagreement about the facts. 

 

Racers are people with rich imaginations and conspiratorial frames of mind. It's the nature of the business. Lots of grudges and vendettas. 

 

 

...Sorry if I have bored you with this story before.... on one of the anniversaries of the Apollo 11 moon landing (I forget which) my editor-in-chief assigned me to go around the garage area on race weekend and get the impressions of various drivers and  personalities on this great achievement. However, the story was tabled when many of my interviewees denied that the moon landing had occurred. 



#5 Marc Sproule

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Posted 27 September 2014 - 18:22

and because i can, here are some links to pics of tim during preseason testing at laguna seca with arie luyendyk in '87...

 

https://www.flickr.c...N03/14727603051

 

https://www.flickr.c...N03/14544255567

 

https://www.flickr.c...N03/14728327864

 

https://www.flickr.c...N03/14543870888

 

https://www.flickr.c...N03/14729823252

 

https://www.flickr.c...N03/14707074926

 

 



#6 Magoo

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Posted 27 September 2014 - 19:16

 

Wow, great photos, Thanks. 



#7 Marc Sproule

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Posted 27 September 2014 - 20:02

Wow, great photos, Thanks. 

 

thank you. 'tis my pleasure to make pics like this available to the folks here.

 

here's the link to all my images on flickr. roughly 2000 now. still have another 70k+ to go through and put the good ones up....

 

https://www.flickr.c...681980@N03/sets



#8 bigleagueslider

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Posted 28 September 2014 - 04:10

After reading Jade's book about the Ilmor 265E and the story about the pop-off valves during that year, I was reminded of some allegations I read somewhere (can't remember where) about Menard tampering with pop-off valves the following year and using illegal valves to secure the pole-position for the '95 500. Does anyone know any more details about this story and what actually happened?

I believe the pop-off valves were provided by CART and they came calibrated and sealed. There were also some pretty strict regulations regarding where the valve could be located, and even the shape of the intake manifold surfaces around the valve inlet.



#9 Ross Stonefeld

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Posted 28 September 2014 - 11:07

Indy 500 valves would have been provided/handled by USAC? For some reason the 500 always seemed to have more 'issues' than other races...



#10 Victor_RO

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Posted 28 September 2014 - 15:15

Indy 500 valves would have been provided/handled by USAC? For some reason the 500 always seemed to have more 'issues' than other races...

 

That's what I thought too, all CART valves were set up for 45in of boost and separate ones were needed for the 265E and the Buicks/Menards/Greenfields of the world that ran at 55 under USAC rules.



#11 Magoo

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Posted 28 September 2014 - 15:51

The traditional mechanical popoff valve was just a calibrated coil spring. Eventually it was at the ragged edge of its capability in regulating boost with the required accuracy. A half-inch of manifold pressure doesn't mean much of anything on a road course but on an oval it's huge. Every year at Indy there was the usual whingeing both ways when USAC passed out the valves. But make no mistake, CART had its own troubles regulating boost. The series essentially imploded in 2001 over its inability to manage the issue. 



#12 bigleagueslider

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Posted 30 September 2014 - 05:03

The 2.65L V8s were limited to 45inHg manifold pressure, the 209ci "pushrod" Ilmor engine was limited to 52inHg, and the stock block V6 pushrod engine was limited to 55inHg manifold pressure for the Indy 500. The 2.65L V8 and the stock block pushrod V6 were both permitted for all CART sanctioned races. I believe Menard ran the stock block pushrod V6 in the 1995 Indy 500. The larger displacement and higher boost permitted with the stock block pushrod V6 allowed higher levels of horsepower for the 4-5 laps of a qualifying run. And pole position for the Indy 500 is worth quite a bit of money.

 

It can be quite difficult to match the relief point of the mechanical manifold pop-off valves used on CART engines with the turbocharger wastegate. Ideally, you try to design your turbocharger and wastegate to never have the pop-off valve open.



#13 Victor_RO

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Posted 30 September 2014 - 06:13

The 2.65L V8s were limited to 45inHg manifold pressure, the 209ci "pushrod" Ilmor engine was limited to 52inHg, and the stock block V6 pushrod engine was limited to 55inHg manifold pressure for the Indy 500. The 2.65L V8 and the stock block pushrod V6 were both permitted for all CART sanctioned races. I believe Menard ran the stock block pushrod V6 in the 1995 Indy 500. The larger displacement and higher boost permitted with the stock block pushrod V6 allowed higher levels of horsepower for the 4-5 laps of a qualifying run. And pole position for the Indy 500 is worth quite a bit of money.

 

It can be quite difficult to match the relief point of the mechanical manifold pop-off valves used on CART engines with the turbocharger wastegate. Ideally, you try to design your turbocharger and wastegate to never have the pop-off valve open.

Didn't the 265E run at 55inHg too? My impression from reading everything available about it was that it ran at 55inHg, then the first announced boost reduction was to 52inHg, and then when FTG announced his new series there was a footnote that said that the boost for purpose-built pushrods would be cut to 48inHg for '95.



#14 Patrick Morgan

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Posted 30 September 2014 - 12:34

The 265E, Buick and let's not forget the Greenfield as they deserve a mention, all ran at 55inHg in 1994. The 55inHg valves by that time were significantly more advanced and became the basis for the grey CART valves of later years. The 55inHg items were anodised black. 

 

The specific issue for 1994 (I can't comment on 1995) was that the valve would open, close and lock closed. I have to confess we (Jade and I) never quite got to the bottom of why this happened. It seemed, as far as anyone could remember, to be related to the mechanism that compensates for ambient atmospheric pressure. That system was designed by Ilmor, I assume at USAC's request. Certainly it was a new problem for Ilmor in May 1994 and according to Mike Devin's account the Buick runners must have experienced the problem but had not reported it. RP, who was very concerned that the 265E would be banned, was absolutely adamant that the problem had to be sorted out to make 100% sure his cars were legal and could not be protested or thrown out. 

 

The PC 23 had electronic boost control and could get very close (compared to the mechanical system alone) to the valve popping. Early in the first week of practice USAC couldn't decide quite what to do about the locked valves so Emerson was sent out to see what boost he could reach... he apparently came back complaining the front wheels were no longer on the ground and please could that experiment not be repeated! I would have to look back though the trasncripts but I seem to recall the figure on the straight before he backed off was 257mph - this wasn't recoded by the speed traps as they were at the end of the straight and the drivers would have to lift well before them.

 

The eventual message was "if your valve is locked, even if your data shows that you have not over-boosted, you're out". Between Mario Illien, Mike Devin and a few others it was sorted out prior to qualifying.


Edited by Patrick Morgan, 30 September 2014 - 12:57.


#15 bigleagueslider

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Posted 02 October 2014 - 07:53

The pop-off valves used in '95 were mechanical designs.  These valves had flow characteristics at their set point that were very abrupt. It was very difficult for the turbocharger to respond quickly to a sudden release of manifold pressure by opening of the pop-off valve. The abrupt release of manifold pressure by the pop-off valve would create a rapid loss of engine power that made things difficult for drivers.



#16 MatsNorway

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Posted 02 October 2014 - 19:40

I would assume you then get studdering or oscillation in the power then. And that some might have mounted their own valve next to it to smoothen things out?



#17 Marc Sproule

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Posted 03 October 2014 - 01:37

if memory serves, don't know when they started, cart teams ran a plastic tube from the popoff to the drivers' helmet so  they could hear when the popoff started to open and then dial back the boost appropriately.



#18 JacnGille

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Posted 04 October 2014 - 00:46

if memory serves, don't know when they started, cart teams ran a plastic tube from the popoff to the drivers' helmet so  they could hear when the popoff started to open and then dial back the boost appropriately.

Sounds familiar to me too.