How 'bout a 4.0 or 4.5L V10?

[ChrisB]

Most of the speculation is fairly certain that the next-gen Champ engine WILL be a V10. However, the displacement is not yet certain. Some have said it will be 3.0L (like F1) and others say 3.5L (like IRL). Well, since this engine will NOT be compatible with either series, why not go with 4.0L?

Why? Sound, torque, and reliability.

We like a nice high-pitched engine sound... which is derived from cylinder count and rpm. (the turbo is essentially just a muffler) The equation to get the pitch of an engine is: hz = rpm/(60/(cyl/2)) Here's a few examples:

v8 8.5k rpm = 567Hz (Nascar)
v8 10.4k = 693 (IRL)
v8 12k = 800 (CART current)
v8 15k = 1000 (CART last year)
v10 19k = 1583 (F1)

We seem to be satisfied with this years 800Hz. This is what the engines were doing in the early 90's and I liked it then too. Now lookit this:

v10 9.6k = 800Hz

In order to get the same 800Hz we have now, from a V10 we only need 9600 rpm. But no way will a 3.0L or 3.5L make 750Hp at this rpm. No problem.. increase the displacement to 4.0L or maybe even 4.5L if needed. That'll do it. The weight increase would probably be minimal too (compared to a 3.5L).

So we get the best of several worlds: a good 800Hz engine sound, good reliability through lower rpms, and good low-end torque through bigger displacement.

Comments anyone?

[WickerBill]

I don't want the revs to be limited to 9600 ("I don't want the revs to be limited" is more accurate). I want to follow a series where the manufacturer has to decide between reliability and pure speed within a set of engineering and materials rules.

[Turn7]

If the V10 becomes reality for CART, I think it will be based on the F1 block and displacement. The mfg's will be able to replace the expensive composite materials with steel or alloy castings for durability.

CART will *could* become the proving ground if the FIA keeps the 2006 mandates for engine durability.

[ChrisB]

WB.... mandated rev-limits, like CART is using now with the XFE, are here to stay. With pressure on both sides from Nascar and the IRL, CART must slash costs to compete. I'm just trying to make the most of the given situation. Actually, rev-limits are not so bad in a (mostly) road-racing series, because most of that flatulent sound is in oval racing where the car is running constantly at the top end.

Otherwise... I have a lot of doubts that the Champ V10 will be in anyway interchangeable with the F1 engine. Besides... since Champ cars will have bigger chassis than F1, maybe it would be good for them to also have much bigger engines too. Kinda the old thing where Europe has small sports cars and America has big muscle cars.

[Turn7]

I see it being based off of the F1 motor before I see a manufacturer stepping up to produce a V10 soley for CART's benefit.


Ford and Ferrari are already selling to multiple teams. If they can make more off of 1 -2 year old technology, they will.

[ChrisB]

I sure hope not. A 3.0L V10 rev-limited to 13k (Pook's number) will probably only make about 600-650hp. Unless if they *substantially* reduce the weight of the chassis (and I doubt they will) this means Champ cars would have a power/wt ratio even less than IRL cars!

[Turn7]

Before this year, I would have agreed with you 100%. However, seeing the lower hp engines this year set a comparable pace as last years cars who knows.

If they can set the engines up so that the torque is strong in the lower rpm range, they should be able to accomplish what they are doing with todays motors since most of the tracks are gone that required super high hp. Sans RA and California, they don't race on an tracks that have long straights that would require high hp/high rpm's.

I am not technical at all with motor stuff so, what I am saying may make no sense what so ever but, that is the way it appears to me.

[Peter Olivola]

Um, ah, yea, well, Road America is back on the schedule. Where have you been?


Originally posted by Turn7
Sans RA and California, they don't race on an tracks that have long straights that would require high hp/high rpm's.

[Napoleon]

Peter, I think he realizes that. What he is saying is that except for RA and California . . .

[Turn7]

Thanks Nap,

Yeah...I was trying to say that RA and California are the only two tracks that are left on the schedule that have long flat out straights that would suffer from a lower HP engine.

Sorry for any confusion.

[Napoleon]

Originally posted by Turn7
Thanks Nap,

Well I know you are a bit of a wallflower and are not very agressive in defending yourself and your beliefs so I thought I would give you a hand.

;)

[RacinM3]

I'm not as concerned about matching the current sound as some. Do the specs right and the sound will be fine. As for V10s - I'd rather not see them. They're not representative of what manufacturers have in their production cars, and they're already being done in F1. I'd rather see turbo inline 4's, or stay with the turbo V8's. Nearly every manufacturer makes one, the other, or both cylinder formats. I would think the engine makers would rather promote something with at least a distant relationship to their production cars.

[ChrisB]

I agree that a turbo-I4 is a great choice... but everything I've seen suggests the V10 is a done deal, and I'm just trying to work within that... and all I'm saying is that before they get too far down the road, maybe this V10 should have a bigger displacement than an assumed 3.0 or 3.5L.

One more thing to add about the packaging issue... the next-gen Champcar chassis should probably also have a shorter wheelbase to negotiate road/street turns better. The wheelbase of the '75 Lola T332 (F5000) was only 102" ... and it was using a Chevy smallblock 5.0L ...so it's NOT unreasonable.

Otherwise, here's some numbers I saved from an old AR1 thread (hoop-98) for a V10 to make 750hp:

3.0L = 14,750 rpm
3.3L = 13,100
3.5L = 12,500

using straight math with those numbers for a V10 to make 750Hp:
4.0L = ~11000 rpm
4.5L = ~9600 rpm

The exhaust pitch of the 4.5L @ 9.6k would be 800hz (same as now)
and the pitch of the 4.0L @ 11k would be ~916hz (a little higher)

[bullet]

Originally posted by Turn7
Thanks Nap,

Yeah...I was trying to say that RA and California are the only two tracks that are left on the schedule that have long flat out straights that would suffer from a lower HP engine.

Sorry for any confusion.

Montreal and Mexico City. Although I have doubts, Spa could be on the schedule by 2005 as well

[ChrisB]

Actually, I was thinking about this bigger engine more in terms of creating more torque to accelerate the cars outta the corners better!

[oddlycalm]

Agreed, they should probably be thinking slightly larger if they want to keep the revs in the 12,500 range.

If what I'm hearing from CART is right, then the V10 will bacically be the current Cosworth V8 with two additional cylinders where the turbo currently resides. I will not be based on the F1 motor.

Cosworth can tool a V10 version of the current V8 simply by changing the foundry patterns for the block and heads and the forging dies for the crank. Beyond that, there would need to be a few edits in the programs on the cam and crankshaft grinders, and that's basically it. Total cost would probably run no more than $100K-$150K, and maybe considerably less if they have a spare set of patterns that can be modified. Considering the turbo and related hardware and plumbing would disappear, cost of operation should be about the same for a season.

My sense of things is that the reason CART is saying V10 is that is what Cosworth is saying they want to supply. I have my doubts as to whether any other mfg's would jump in right away, but the economy won't stay on the floor forever. The spec would be the same for any other mfg. that was previously involved in CART, i.e. they could easily retool their previous V8 to get all the basic pieces. Ilmor, Honda and Toyoda have such tooling, or their various vendors do.

How much lattitude there is in displacement is debatable, but there is certainly some ability to increase the stroke a bit if need be as long as they intend to stay with a low rev limit.

[pchall]

How about just making an NA V8 out of the last generation of Turbos and taking the displacement out to 3.0l with and increased stroke and a bit more bore? RPM would go down and be controlled by the stroke rather than a rev limiter.

The next chassis needs to be smaller, tidier, and a couple of hundred pounds lighter anyway, so lower HP V8 would do just fine.

[FCYTravis]

Originally posted by pchall
How about just making an NA V8 out of the last generation of Turbos and taking the displacement out to 3.0l with and increased stroke and a bit more bore?

Wouldn't make near enough horsepower. The 3.5 litre V8s that IRL uses are pushing it at 710ish.

[ChrisB]

My sense of things is that the reason CART is saying V10 is that is what Cosworth is saying they want to supply. I have my doubts as to whether any other mfg's would jump in right away

Yep. I think its a done deal with Cosworth. Even if no-one else makes a V10 for the next-gen engine in '05 (or '06) we can at least be fairly certain that Cosworth will ...even though for the first year or so it might be an all-Cos field kinda like now (which isn't so bad, really).

And since there's still some time, I'd hope they'd at least consider making it a 4.0L for just a little extra margin.

[pchall]

Originally posted by FCYTravis
Wouldn't make near enough horsepower. The 3.5 litre V8s that IRL uses are pushing it at 710ish.

600 HP in an Atlantics sized and weight chassis would be just fine.

[nrc]

Originally posted by pchall
600 HP in an Atlantics sized and weight chassis would be just fine.

But you wouldn't want to hit a wall with it.

[ChrisB]

I really do think the Cos V10 is a done deal.... and that the next-gen chassis won't be too far off from what they are now... but if they could combine a 750hp V10 with a slightly lighter and shorter-wheelbase chassis... Hey!

[FCYTravis]

Originally posted by pchall
600 HP in an Atlantics sized and weight chassis would be just fine.

Yowza. That would be a recipe for major driver injuries. Atlantics aren't engineered for 200+ mph and almost certainly wouldn't withstand the impacts generated at those speeds.

[pchall]

Originally posted by FCYTravis
Yowza. That would be a recipe for major driver injuries. Atlantics aren't engineered for 200+ mph and almost certainly wouldn't withstand the impacts generated at those speeds.

My description calls for an Atlantics SIZED car, guys. Certainly that general package size can be engineered for the speeds and safety needs of champcars.

Current champcars run a 124" wheelbase and an overall length of 195". Take 18" out of the wheelbase and you've got the tidier, more nimble car closer to the size of the current Atlantics chassis wheelbase of 104" and overall length of 167". Atlantics are already 150 lbs heavier than a contemporary F1 car and F1 cars are keeping drivers whole in some tremendous hits these days. If more structure is needed for superspeedway use the current Atlantics minimum weight is still 300 lbs lighter than a champcar.

Have you noticed that Atlantics often produce much better racing on courses that champcars have "outgrown"? I've observed this on miles and on road and street courses. A tidier champcar will mean better racing.

BTW, when I first got interested in champcars a "long" formula car had a 96" wheelbase.

[Sean O'Gorman]

I think I have to say pc's idea sounds like the best option to me.

[ChrisB]

when I first got interested in champcars a "long" formula car had a 96" wheelbase

Yep... the wheelbase of 60's Champcars were about 96"... 70's F5000 was about 102"... 90's F1 was about 104-109". Even WC are only 110". Champcars wheelbases are tooooo long right now... and hopefully they'll shorten them when they design the new chassis to go with this Cosworth V10.

Which IMO should be at least 4.0L or even 4.5L for better reliability and torque.

[nrc]

Smaller, lighter cars would be nice, but the first priority has to be safety. It's going to be tough to make the cars smaller, maintian the current safety standards and not drive the cost of the chasis up.

Whatever can be done without sacrificing cost and safety, I'm all for. But the most important thing is: no airboxes. :)