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N2racin44
Guest
Cars are heavier, not as much downforce either. Beginning next year there will be even less downforce as well.
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wlfyk62
Guest
IndyCar Racing League cars are all Fiberglass so that means its lighter so that the car can go faster, plus IRL has more Pony's under the hood the Nascar does. Nascar uses sheetmetal and metal thats heavy to whigh the cars down also.
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17_Fan
Guest
IndyCar Racing League cars are all Fiberglass so that means its lighter so that the car can go faster, plus IRL has more Pony's under the hood the Nascar does. Nascar uses sheetmetal and metal thats heavy to whigh the cars down also. [/b][/quote]
I think there might be a tad more to it than that. Like N2 said, there is more downforce on an Indy car. The principle of the design dictates that. With the wings and the low proximity to the ground compared to a cup car. Someone else with tons more 'sperience on areo should be able to explain it better than me.
Weight is a factor, but not that much of one.
The engines get more HP...that has a lot to do with them being fuel injected & not carburated. They're not the clunky old push rod engines like Nascar, they use over-head cams. And the Indy cars burn methanol fuel also. Methanol allows them to use much higher compression ratios.
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HardScrabble
Guest
Strange as it may seem, the IRL engines produce less horsepower than the Winston Cup engines.
Figure that first off they are quite a bit smaller. The limit is 2.5 liters (213.6 cubic inches) compared to the 358 cubic inches of a Cup engine. Both are normally aspirated, but the dual overhead cam, four valve per cylinder arrangement of the IRL powerplant gives it more hp per inch. The power production is further limited on the IRL piece by a mandated maximum rpm of 10,300. (NASCAR's pushrod engines have yet to reach that number on a sustainable basis though some teams are pushing 9500 regularly)
Anyways, the engines make somewhere between 650 and 675 hp according to the latest numbers. The Cup engines are probably somewhere in the 750 to 775 hp range.
The big difference is handling. A combination of weight, aerodynamics, tire size and chassis construction. The IRL car is probably limited in its speed by hp more than handling. That allows greater latitude for on track manuevers and multi groove racing. The Cup cars are limited more by handling than hp. They do not share the same flexibility when it comes to where on the track they can run.
Figure that first off they are quite a bit smaller. The limit is 2.5 liters (213.6 cubic inches) compared to the 358 cubic inches of a Cup engine. Both are normally aspirated, but the dual overhead cam, four valve per cylinder arrangement of the IRL powerplant gives it more hp per inch. The power production is further limited on the IRL piece by a mandated maximum rpm of 10,300. (NASCAR's pushrod engines have yet to reach that number on a sustainable basis though some teams are pushing 9500 regularly)
Anyways, the engines make somewhere between 650 and 675 hp according to the latest numbers. The Cup engines are probably somewhere in the 750 to 775 hp range.
The big difference is handling. A combination of weight, aerodynamics, tire size and chassis construction. The IRL car is probably limited in its speed by hp more than handling. That allows greater latitude for on track manuevers and multi groove racing. The Cup cars are limited more by handling than hp. They do not share the same flexibility when it comes to where on the track they can run.
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17_Fan
Guest
This just explains some of the reasons why Indy cars are faster than stock cars. Doesn't necessarily explain why the finishes are closer in Indy cars though. 
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HardScrabble
Guest
Not exactly...but it tells ya that since the limiting factor for the IRL folks is hp it is a bit like the restrictor plate racing in NASCAR. There is some more variance in performance than at the plate races much of which is probably attributable to the aero differences in the draft.Originally posted by 17_Fan@Sep 9 2003, 03:24 PM
This just explains some of the reasons why Indy cars are faster than stock cars. Doesn't necessarily explain why the finishes are closer in Indy cars though.
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Flametamer
Guest
Hey, what about the Darlington spring race? Ya don't see a finish like that in the IRL either. The Indy cars would have been a parts pile after that much rubbin! 
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Ward Burton
Guest
The infiniti series race at Kansas was awesome too!!!!
J
j ozzman 5000
Guest
i saw that race and i wondered "why the bsence word: can't NASCAR's chicagoland race be that exciting?"
bsence word: can't NASCAR's chicagoland race be that exciting?"
1
17_Fan
Guest
Not exactly...but it tells ya that since the limiting factor for the IRL folks is hp it is a bit like the restrictor plate racing in NASCAR. There is some more variance in performance than at the plate races much of which is probably attributable to the aero differences in the draft. [/b][/quote]Originally posted by HardScrabble+Sep 9 2003, 03:22 PM--></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (HardScrabble @ Sep 9 2003, 03:22 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin--17_Fan@Sep 9 2003, 03:24 PM
This just explains some of the reasons why Indy cars are faster than stock cars. Doesn't necessarily explain why the finishes are closer in Indy cars though.
The biggest variance being that the Indy cars don't run in dangerously tight groups like a restrictor plate race at 'dega & Daytona.
I'm assuming the IRL limits the HP so they don't have the problem CART had at Texas a few years back with drivers almost blacking out from the +G's.
HS, you mentioned the IRL cars have "greater latitude for on track manuevers and multi groove racing" which was especially true at Chicagoland. The first year the Cup cars were there it was a one groove track. This year they did run two grooves, but whoever was the leader, took off from the pack & it was tough to run him down. The Indy race this past Sunday, Richie Hearn took off from the pack while Tomas Sheckter & Felipe Giaffone battled side by side for 2nd & 3rd for quite a few laps. Sam Hornish eventually got in front of Tomas & once they got in line they quickly ran down Richie. Last year's IRL race, Sam & Little Al were running side by side for the last 20 laps trying to decide the winner. That may answer 24/48/12's question why they have closer finishes in the IRL.