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  • IRL engines

    Been watching some clips of the IRL at Indy. Man, those engines sound terrible.

    i think they were 4.0 L Aurora (GM) pushrod units?

    whats the story behind the IRL engines? Builders, design, why the move to pushrod?

  • #2
    There never was a pushrod Olds or Infiniti engine in the IRL. And the sound improved with the switch to or from a flat crank (I can't remember which).
    It's a Hoosier thing, you wouldn't understand...

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    • #3
      I have been told that back in 1994 the first Honda CART/Indycar engines sounded horrible compared to the other Quadcam engines of Ford and Ilmor (Ilmor\D) due to the use of a different crankshaft lay-out.

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      • #4
        Originally posted by Redgloves99 View Post
        Been watching some clips of the IRL at Indy. Man, those engines sound terrible.

        i think they were 4.0 L Aurora (GM) pushrod units?

        whats the story behind the IRL engines? Builders, design, why the move to pushrod?
        The original IRL 97 to 99 engines were supposed to be modern "Stockblocks". They were quadcam 4.0L NA engines that were supposed to be the same as seen in production cars.
        However none of the parts actually came out of production cars. You would buy ether the Olds parts or the Infinity parts from ether. Then have your engine builder put it all together. They were not sealed and there were a few things you could do to massage them. They ran from 10,500rpm to 10,300rpm (IRL kept redoing the rules to dial back the power)

        Gen 2 (2000 to 2002) did away with this to some extent. The production based requirement was dropped and thus this allowed them to use things like 180 degree cranks and different firing orders. The displacement went to 3.5 and The RPM limit was also raised a bit. But by 2002 it was down to 10,700rpm
        Silly Season scorecard and Where are the Indy 500 winning cars! http://inrd.gotdns.com/indystuff/

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        • #5
          Originally posted by midtown View Post
          There never was a pushrod Olds or Infiniti engine in the IRL. And the sound improved with the switch to or from a flat crank (I can't remember which).
          The flat, or 180° crankshaft, was used on the initial generation of engines. I think the change to the cross plane, or 90° crankshaft, occurred in 2000.

          The 180° crankshaft has been used in racing applications for decades. It fires sequentially on one cylinder bank to the other. The firing order can vary, for example 1-6-3-2-7-4-5-8 or 1-4-5-2-7-6-3-8, but in all cases it follows a R-L-R-L-R-L-R-L pattern. The flat plane crank revs faster and higher than a 90° crank, because it doesn't have the large counterweights and greater rotational mass of the crossplane crank.

          The flat crank does have a couple of disadvantages compared to the crossplane crank, one being significant second order vibrations, and the other, painfully obvious to those of us watching those early races, a loud and discordant exhaust note.

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          • #6
            You got it backwards. Cross plane 97 to 99, flat plane from then on.
            Silly Season scorecard and Where are the Indy 500 winning cars! http://inrd.gotdns.com/indystuff/

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            • #7
              Yep. The IRL engines first used 90° crankshafts which gave those engine the bellowing V8 sound (like a NASCAR stocker). The later switch to the flat, 180° crankshafts changed the sound to be more like that associated with the CART quad-cam motors. Most American V8s use 90° crankshafts, but the more recent Shelby GT350 Mustang's 5.2 liter engine uses a 180° crankshaft as do Ferrari V8 engines.
              "I would really like to go to NASCAR. I really enjoy NASCAR and if I could be there in a couple of years that's where I'd want to be." - Jeff Gordon (after testing a Formula Super Vee)

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              • #8
                Originally posted by Indyote View Post
                I have been told that back in 1994 the first Honda CART/Indycar engines sounded horrible compared to the other Quadcam engines of Ford and Ilmor (Ilmor\D) due to the use of a different crankshaft lay-out.
                Beauty is in the eye of the beholder. The '94 Hondas had a deep roar to them. In '95 it was a high pitched screetch. What sounded better is a matter of personal taste.
                The Ayn Rand of Indycar

                No one had to badge the Offy.

                Crapping all over threads since 2000.

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                • #9
                  The first Honda engines used the "Big Bang" cranks that used a staggered firing order based on Honda's experience with racing motorcycle engines. It didn't work so well. Those engines also used iron engine blocks.
                  "I would really like to go to NASCAR. I really enjoy NASCAR and if I could be there in a couple of years that's where I'd want to be." - Jeff Gordon (after testing a Formula Super Vee)

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                  • #10
                    Originally posted by Spike View Post
                    The first Honda engines used the "Big Bang" cranks that used a staggered firing order based on Honda's experience with racing motorcycle engines. It didn't work so well. Those engines also used iron engine blocks.
                    In sure Rahal never wants to see one again..

                    In any case to summarize.

                    1997-1999 4.0L 10.500 to 10,300rpm. Buy parts from Infiniti or Olds and assemble. Nominally production based. 90 degree cranks.
                    2000-2002 3.5L 11,000 to 10,700rpm. Buy parts from Infiniti or Olds and assemble. 180 degree cranks
                    2003 (and first couple races in 2004 before Indy) 3.5L 10,300rpm Sealed lease from Chevy,Honda or Toyota. 180 degree cranks (presumably)
                    2004-2006 3.0L 10,300 Sealed lease from Chevy,Honda or Toyota (Chevy and Toyota left after 2005)
                    2007-2011 3.5L single source detuned running on Ethanol.
                    Silly Season scorecard and Where are the Indy 500 winning cars! http://inrd.gotdns.com/indystuff/

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                    • #11
                      Originally posted by PaddockMoose View Post

                      In sure Rahal never wants to see one again..

                      In any case to summarize.

                      1997-1999 4.0L 10.500 to 10,300rpm. Buy parts from Infiniti or Olds and assemble. Nominally production based. 90 degree cranks.
                      2000-2002 3.5L 11,000 to 10,700rpm. Buy parts from Infiniti or Olds and assemble. 180 degree cranks
                      2003 (and first couple races in 2004 before Indy) 3.5L 10,300rpm Sealed lease from Chevy,Honda or Toyota. 180 degree cranks (presumably)
                      2004-2006 3.0L 10,300 Sealed lease from Chevy,Honda or Toyota (Chevy and Toyota left after 2005)
                      2007-2011 3.5L single source detuned running on Ethanol.
                      Here's some more specs

                      1997-2003
                      35 gallon tanks (methanol)

                      2004-2005
                      30 gallon tanks (methanol)

                      2006
                      30 gallon tanks (90% methanol - 10% ethanol blend)

                      2007-2011
                      22 gallon tanks (98% ethanol - 2% gasoline blend)
                      Doctorindy.com

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                      • #12
                        During practice in '98 Team Menard was pitted a couple pit away. I can still vividly remember the crew rolling out Buhl's backup car with Stewart and Larry Curry walking by. It seemed odd but we knew what was up when they fired the car and the exhaust note was distinctively different.
                        Normally after you roll out you warm up again as the driver is climbing in. They didn't fire that until he was ready to roll. Stewart on a shakedown went about 5th quick in 5-6 laps, pulled into the pits and shut it down and got out. The crew rolled the car back to the garage and closed the door. Officially the were testing a new exhaust, we all knew what was up.

                        Really the only things used by most of the builders by the end of '97 was the block, sump, cam covers, and small bits. Cams, cranks, rods, pistons, oil pumps were sourced by the builders. Our builder at the time was using Bruce Crower's stuff same as Comptech, Menard was doing their own thing, Rick Long was on his own program too.

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                        • #13
                          Originally posted by PaddockMoose View Post

                          In sure Rahal never wants to see one again..

                          In any case to summarize.

                          1997-1999 4.0L 10.500 to 10,300rpm. Buy parts from Infiniti or Olds and assemble. Nominally production based. 90 degree cranks.
                          2000-2002 3.5L 11,000 to 10,700rpm. Buy parts from Infiniti or Olds and assemble. 180 degree cranks
                          2003 (and first couple races in 2004 before Indy) 3.5L 10,300rpm Sealed lease from Chevy,Honda or Toyota. 180 degree cranks (presumably)
                          2004-2006 3.0L 10,300 Sealed lease from Chevy,Honda or Toyota (Chevy and Toyota left after 2005)
                          2007-2011 3.5L single source detuned running on Ethanol.
                          https://us.motorsport.com/indycar/ne...ebuts/1673488/
                          Yes, an individual team could buy parts and assemble their own engines. I believe the majority bought assembled engines from the 4 builders.
                          Katech, Inc. (Mt. Clemens, Mich.); Rocketsports Evolution (Lansing, Mich.); Roush Technologies (Livonia, Mich.); and Team Menard (Indianapolis, Ind.).
                          IRL mandated engine price of $75K

                          The 'stock block' aspects were limited to bore spacing and cylinder bank angle(and perhaps cam drive system). Supposedly the Olds engine was based on the engine they used in sports car competition.

                          https://www.motorsport.com/indycar/n...-in-1997/4483/

                          The Nissan/Infiniti was also based on an existing race engine.
                          BAN SHREDDED CHEESE! MAKE AMERICA GRATE AGAIN!

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                          • #14
                            The Nissan was also used in sports cars. I'm a Nissan guy at heart. NIF is short for Nissan Indy Fan. Only got to run the Walkinshaw built Nissan in '01 when we tested Herbert. We were running Menard engines the rest of the year, one hot lap at Kentucky and Wardy said we had to race it. Menard was making the most horsepower for the Olds at the time and we estimate the Infiniti to be a good measure more powerful. The same VH41DE block was used in the R90C, the IRL, Japanese Super GT, the Infiniti Pro Series , the McLaren MP-4. While not exactly stock (the Olds wasn't either) they were quite close to the same one you could get in a Q45.

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                            • #15
                              I never heard a turbo-charged V6/V8 from the 80s/90s I didn't like. That said, while not ideal, I never had a huge issue with the IRL NA engines in the 90s. For whatever the reason, once the Japanese got involved in 2003, the engines sounded completely awful. So bad that they mercifully introduced mufflers.
                              "If your car was a dog, then you had to figure it out and test your own limits. And we didn't go to a wind tunnel – we did it in the first turn at Indianapolis."

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