New IRL Engine Regs for 2007

[Tim Northcutt]

Bottom line:

They're going back to the 3.5 L displacement, which apparently will add 300 miles worth of life to the engines.

It'll also give the engines more torque for the road courses.

Today's Indy Star had the item today. Here is the link:

http://www.indystar.com/apps/pbcs.dl...608230451/1052

My Thoughts:

1. The lowered the displacement to 3.0 L beginning with the 2004 Indy 500 was due (according to the IRL at that time) to the speeds getting too high with the 3.5 L engines...

So what will be changed on the return to the 3.5 L engines to alleviate that issue this time around?

2. At least on the Ovals, I thought that the 3.0 L engines gave us better racing, and they required drivers to do a decent amount of shifting to keep the revs up in the engines....

The 3.5's didn't require that, and I think this is a downside to returning to the 3.5 L configuration.

3. The "needed" change to the 3.0L in 2004 has now reverted back to where they were for most of the life of the IRL in displacement...thus the change was expensive and short-lived when compared to the life of the Series itself.

Sorry...but this doesn't make a lot of sense to me, unless Honda requested it.

[paul-collins]

My guess is this is similar to what Cosworth did in Champcar when they became the sole source for engines. Cosworth reduced revs and upped boost to maintain power.

More displacement in the Hondas means less revs for the same power, and less revs theoretically means longer periods between rebuilds.

[knighty]

but what if another manufacturer comes along and they start pushing the 3.5 engines again - surely they will again be back to square 1 with cars going too fast.

but lets be honest reducing the top speed from say 230mph down to say 210mph........210mph is still quite fast enough to well and truly kill a driver......did the 3.0 engine save Paul Dana?.....no it certainly didnt.......I saw the crash via a web link video and it was brutal to say the least

[paul-collins]

I'd say that the change in specs suggests the IRL don't believe there will be any competitor for Honda in 2007.

[Tim Northcutt]

In fact, the very first races with the 3.0L saw a reduction in speeds by about 10 mph.

But within a few months, they were climbing up again and at Indy this year, Sam Hornish's qualifying average was within 2 mph of what Helio Castroneves won the pole with in 2003.

Concerning the engines, you could be right, Paul...but it makes me wonder if they might not grandfather back in some of the 3.5s that Chevy built, since those were not leased, and teams actually owned them prior to Honda and Toyota coming into the Series.

I seriously doubt that the scenario I have described would ever happen (in fact, I think it would have a snowball's chance in Hades), but they could get competitors back by doing so, since the smaller budget teams still own those engines.

[paul-collins]

The real question in my mind is, if they're changing the engines, why not go to 3.4 instead of 3.5? Maybe inlet-control instead of rev-limit, while they're at it...

[Bob Riebe]

Originally Posted by paul-collins

The real question in my mind is, if they're changing the engines, why not go to 3.4 instead of 3.5? Maybe inlet-control instead of rev-limit, while they're at it...

Gee-or maybe Stromberg 97s running on coal gas, or a total spec. series so as to try to not pretend to be something it once was, but no longer is....

If the sanction had more than half of a brain, find a 1978 USAC rules book throw it on the table and say " the're the new rules boys, have at it."
Bob

[drdisque]

old chevrolet engines cannot be grandfathered in as they are not supported by a manufacturer as mandated by IRL rules.

[kingfloopy]

I always wondered why teams couldn't use the old Toyota and Chevy engines that were left over. If they really wanted they could just change the rules or allow the other engines only for Indy to help pad the field.

J.D.

[Bob Riebe]

Originally Posted by kingfloopy

I always wondered why teams couldn't use the old Toyota and Chevy engines that were left over. If they really wanted they could just change the rules or allow the other engines only for Indy to help pad the field.

J.D.

One must remember that Tony G., the person who turned the IRL into the very thing he said he created it to get away from, is still running the show.

[drdisque]

well, Toyota owns all their engines and aren't selling them, so don't expect to see them any time soon.

All the Chevrolet engines and its design is owned by Cosworth. Running them would probably cost as much or more than a honda engine lease costs these days and you'd probably be a backmarker.

Remember, engine costs made a huge drop from last year and are making another huge drop next year.

[climb]

Originally Posted by drdisque

...

Remember, engine costs made a huge drop from last year and are making another huge drop nxt year.

good point.

I think that, as far as now, that's the most relevant issue.
When there's no engine competition actually 3.0 or 3.5 doesn't make a big difference, whereas saving money is of paramount importance to keep current entries and, possibly, gain more.

[ian_w]

The 3.0 litre engines running now are a lower spec than those run at the end of 2005. This is to reduce costs and increase rebuild mileage.

The main factor in the switch to 3.5 litre is the use of ethanol, which gives substantially less power than methanol. In order to maintain the current power levels, you either need to go back to something like the 2005 engines with their high costs or go up in capacity. The switch to 3.5 litre should hopefully further reduce costs compared to the current 3.0 litre engines.

[Bob Riebe]

Ethanol does not give substantially less power than Methanol.
Its characteristcs are different but horsepower difference is minor.

Bob

[JohnSSC]

Agree with your comment on the rules, Bob!

Can anyone say: "Offenhauser?" "Novi" is shorter...

[ian_w]

Originally Posted by Bob Riebe

Ethanol does not give substantially less power than Methanol.
Its characteristcs are different but horsepower difference is minor.

Bob

Bob, I'm afraid I have to disagree with you. Ethanol has a slightly lower calorific value but more importantly it has a much lower latent heat of vapourisation. This means there is much less cooling of the inlet air with ethanol. Overall ethanol is at least 5% less potent than methanol.

[Bob Riebe]

Originally Posted by ian_w

Bob, I'm afraid I have to disagree with you. Ethanol has a slightly lower calorific value but more importantly it has a much lower latent heat of vapourisation. This means there is much less cooling of the inlet air with ethanol. Overall ethanol is at least 5% less potent than methanol.

Some boys have been running it in sprint cars for over decade (sponsorship sort of thing) and it was first run at Indy back in the early nineties.
Bob

[ian_w]

On a 'normal' engine, you will probably only lose a small amount of power due to the lower calorific value of ethanol. The IRL engine are however far from 'normal' and have highly sophisticated fuel injection systems that exploit the evaporation effect of methanol to cool the inlet air and thus increase power. This evaporation effect is much lower with ethanol and this results in the performance loss I described in my previous post.

[Bob Riebe]

Originally Posted by ian_w

On a 'normal' engine, you will probably only lose a small amount of power due to the lower calorific value of ethanol. The IRL engine are however far from 'normal' and have highly sophisticated fuel injection systems that exploit the evaporation effect of methanol to cool the inlet air and thus increase power. This evaporation effect is much lower with ethanol and this results in the performance loss I described in my previous post.

Sprint car engines have fuel injection, and produce in excess of 800 hp, also.

A beginners crate engiine starts at $40,000 and if you want to win double or more.
SO
The difference in how it functions in the strictly controlled IRL engines, and the slightly less controlled sprint car engines is little.
If you are expecting noticible drops in speed due to ethanol, it is not going to happen, and if Tony G. pulls his head out of his nether regions and opens the rules, it will make a difference only to those trying to sell ethanol as a street fuel.
It is dfferent, but not enough to make an impact.
Bob

[ian_w]

Bob, sorry to keep arguing with you but as I explained the fuel injection systems on the IRL engines are highly sophisticated with two injectors per cylinder. The positioning of these injectors is critical as is determining exactly how much fuel to inject thro each one at any given time. I doubt that any Sprint car has anything remotely similar - aren't they fitted with mechanical injection?

The injection system is one of the few areas of free development within the IRL rules. The difference between getting the injection system right or wrong is of the order of 15% in terms of peak power using methanol. The performance difference between Honda and Toyota/Chevy last year was probably at least partly due to the Honda having a more highly developed fuel injection system.

I work on this type of engine for a living, trust me - ethanol gives at least a 5% reduction in power on an IRL engine.