1994 and 1995 Indianapolis 500s

[bil588]

Is it true that the regulations allowed more engine displacement and boost for pushrod engines for the 1994 and/or 1995 Indianapolis 500s?

"Mercedes-Benz used the Indianapolis 500 to debut their Mercedes 209 engine (the 209 stands for the size of the engine in cubic inches). The Penske cars were dominant for the entire month."

- http://en.wikipedia.org/wiki/1994_Indianapolis_500

"In 1994, the Indianapolis 500 was won with an engine from Mercedes-Benz which, realizing that a loophole in the rules for production-based engines would include any pushrod engine,[citation needed] built a very unusual purpose-built pushrod engine with a significant power advantage. This was done knowing that the "forgotten" loophole would be closed immediately after they took advantage of it,[citation needed] and so the engine would in fact be usable only for this single race.
Starting from 1995, Mercedes-Benz rebranded the Ilmor engines and achieved six wins in their first full season, also reaching second in the drivers championship powering Al Unser Jr.."

- http://en.wikipedia.org/wiki/Mercede...rsport#Indycar

[bil588]

Were the rules changed for 1995 regarding engines?

[racer69]

It had more to do with the fact that the Indy 500 was not a CART race (though it counted for the CART championship most years), it was sanctioned by USAC, so the race regulations were different, which allowed stock blocks to compete.


I recall a rule change for the 1995 race in the wake of the 1994 Penske-Mercedes domination with that engine, but the Buick/Menard stock block motors still scored a 1-2 (Scott Brayton from Arie Luyendyk) in qualifying.

[bil588]

do you mean production-based engines?

[bil588]

The Indy 500 website doesn't have old regs posted.

http://www.indy500.com/

[D-Type]

According to Higham

The Indianapolis regulations allowed
1979 -84 - 4500cc normally aspirated, 2650cc turbocharged, 5878cc stock block normally aspirated, 3430cc stockblock superchargedcharged
1985-96 - 2650cc turbocharged and 3430cc stockblock supercharged. Normally aspirated engines phased out

CART
1979 to date - 2650cc turbovharged, 3430cc stockblock supercharged

IRL
1995-96 2650cc turbocharged
1997 to date production based 3500cc normally aspirated.

Surprisingly, the Wikipedia entry looks about right. As I understand it, the intention of the regulations was stockblock 3430cc supercharged engines but the wording was pushrod engine. So Penske persuaded Ilmor to produce a Mercedes-benz branded pushrod racing engine which wiped the board in 1994 and was banned for 1995. I don't know if it was supercharged or whether the regulations sid 'forced induction' allowing it to be turbocharged.

[bil588]

Who/what is Higham?

[Bob Riebe]

Originally Posted by D-Type

According to Higham

The Indianapolis regulations allowed
1979 -84 - 4500cc normally aspirated, 2650cc turbocharged, 5878cc stock block normally aspirated, 3430cc stockblock superchargedcharged
1985-96 - 2650cc turbocharged and 3430cc stockblock supercharged. Normally aspirated engines phased out

CART
1979 to date - 2650cc turbovharged, 3430cc stockblock supercharged

IRL
1995-96 2650cc turbocharged
1997 to date production based 3500cc normally aspirated.

Surprisingly, the Wikipedia entry looks about right. As I understand it, the intention of the regulations was stockblock 3430cc supercharged engines but the wording was pushrod engine. So Penske persuaded Ilmor to produce a Mercedes-benz branded pushrod racing engine which wiped the board in 1994 and was banned for 1995. I don't know if it was supercharged or whether the regulations sid 'forced induction' allowing it to be turbocharged.

No one thought anyone would take the time to develope a push-rod racing engine.
The Ilmore Mercedes was blown.
CART and USAC had different blower pressure levels which is why the two valve engines worked in USAC.
Push-od NA engine were not phased out, both USAC and CART would not give Dan Gurney, or anyone, the inches necessary to run a two valve engine without being at grenade levels.
USAC depending on year first allow push-rod NA engines of 255 inches, then 305, then 355 production and 320 special heads.
NA full racing engines were limited to first 256, then 274 inches cubed.

USAC never really banned anything but made turbines hopeless with intake rules; all else just was rarely to never used, until the blown full race push-rod engines showed up then they stuck their heads up their butts and banned those.
After that they just faded away.
CART at least at first, also allowed the push-rod NA engines, as Gurney won at Milwaukee with one, and also had his car on the front row at Indy with one, during the CART years.

Although Gurney was a CART founding father, his was one of the first people they crapped on.
Bob

[D-Type]

Originally Posted by bil588

Who/what is Higham?

The International Motor Racing Guide - Peter Higham - 2003, ISBN 189361820x.
A thoroughly researched and accurate fact book or statistical record covering al major series from Grand Prix racing to NASCAR. As a measure of its accuracy - it correctly records the Haresnape and Catlin retrospective AAA champions and the 1939 European Champion dual candidates.

[bil588]

Mercedes-Benz 500I Engine

11,000 plus miles of testing for one race?

(Indy was bigger back then)

http://rides.webshots.com/photo/2096...99963812UPOnLy

[Graham Clayton]

The rules allowed the Mercedes 209 to have a larger capacity (209 ci versus 161.7 ci for the overhead cam engines), plus a bigger turbo boost (55 compared to the 45 of the Ford and Honda engines).

Rule 11.07 had existed since 1991, but since it only applied to the Indy 500, it wasn't viable for a team to build a new engine purely for that one race.