Hemi '99

[azazello]

Hi all,

Does anybody know a good place to find more information on the Hemi '99 that MP is designing for NHRA/IHRA? I saw a brief article in Mopar Action this month and wanted to find out some more about this sweet mill.

Thanks,

Pat

[prostock]

There has not been very much information released to the public yet. Nickens was to have one running by Indy last year, but I was told one of his employee's damaged a set of the heads porting them, and they had to start from scratch.

He also had personnel changes that put them even more behind.

Larry Morgan is supposed to have one running at Pomona. I'll believe it when I see it.

It is not a true "hemi". It is actually a combination of a hemi and wedge combustion chamber. From what I'm told, Ray Barton redesigned the valve train, which is what has held the hemi back in today's pro stock (the old valvetrain was too heavy for 10,000rpm).

[hemivaliant]

Go to http://www.car-truck.com/ There's an interview posted there were they talk some about the upcoming debut of the new Hemi. There's also an interview with Larry Morgan in the latest edition of Mopar Performance News on the engine. He says he will have his ready for first race at Pomona in Feb. 2000.


krseeger

[LA360Dart]

The new Hemi is just a MOPAR knock off of the Oldsmobile DRCE (updated of course) it uses the same chamber just turned 90 deg. so that intake and exhaust are across from each other in line with the ports. The article stated that the chamber is 55 cc's in no way that is a Hemi. The T/F and Alcohol motors may have Hemi heads. Also a note I've seen the new Mopar part catalog and Ma Mopar has new Commando heads for SB that are aluminum using standard valve train and port configuration.

[DartGT66]

Of course it can't be a true Hemi. It will propably have the plugs go through the valve covers, to make it look like a Hemi (just a guess). Actually it's more like a poly engine than anything else. The current Pro Stock engines are very well developed, you can't just pick another design and make it a winner; if you could it would have been done already. The fact is that a wedge style engine makes more power than a similarily prepped true Hemi, and even mopar performance can't change it.

[Larry S.]

Wrong! The hemi head is a much more efficient design than the wedge head. It just costs more to manufacture. The centrally located spark plug gives a better fuel mixture burn, and the ports have a straighter more direct shot at their respecive manifolds. The only real problem with the hemi is the unwieldy valve train setup, which is a horsepower robber, but the efficiency of the hemi head more than makes up for it. If the hemi is so inefficient at making horsepower, why was it banned from NASCAR in the first place? Because the WEDGE engines couldn't keep up with it! Why is the hemi the dominating motor in drag racing's fuel classes, because the WEDGE engines can't compete! Why was it that in the late sixties and early seventies the only engine that could give a 426 hemi car a run for it's money was a 440 6pac car? Because the WEDGE engines couldn't compete! The only reason the 440 6pacs could do it is because the hemis were hard to keep tuned and weren't usually running to their capability, plus the fact that the 440s were about 100 pounds lighter! Why did the 426 wedge engine go out of production after the 426 hemi was developed? Because the HEMI made more power! You build a 426 wedge and a 426 hemi to the same specs and dyno them, and I'll put my money on the hemi every time. Why? Because I'm not a gambler and I hate loosing money!

[caveman]

In the day ,the hemi was the best,it had the best design to combat detonation,and being a cross flow head it made the most HP period.The valve train is heavy and it s geomitry isn't good for 10000 rpm blasts.As far as the best chamber design now ,,only the experts know for sure.Larry S is 95% right though.

[GILBO]

hey if wedges are so bad, why did the nhra made the hemis carry all most twice the weight as a wedge per cubic inch!!! because they could not keep up!!! hey 20 years of advancement in wedges, while hemis were all but outlawed by the rules!!! has given the wedges a advantage for the short term. ray barton has designed a new valve train that should bring the hemi into the 21st century. i own a stout 440 in a 69 charger r/t, but it's no hemi!!!

[JCNathan]

I can hardly wait (but I guess I'll hafta) to see this Hemi 99!! I've been reading as much as I can but sooo much differing info. I would be surprized that MoPar would abandon the hemi design because of it's superior volumetric efficiency.

As all you folks know, cylinder head design is THE critical factor in developing horsepower. In simplist terms, the designer is trying to make the actual mass of air coming into the cylinder equal the theoretical maximum mass of air for a given bore and stroke. The hemispherical or similar form (like the pentachamber) provides the highest volumetric efficiency of any head design. The downside to this design is the size (or volume) of the chamber -- to get those nice big valves and smooth intake/exhaust runners -- requires a correspondingly longer piston to obtain those high compression ratios. Wish I knew if the increase in volumetric efficiency offsets the increase in weight of the reciprocating parts (pistons).

I fear that some of the other posts may be right - MoPar may just improve the design of those bogus GM "billet" heads.

Gosh, I wish I were back in design again -- this would be a fun time to be racing!!

Later. . .

[DartGT66]

NHRA had weight factors for different engines, and the hemis factor was 1.00. Ford Cleveland had a bigger factor than a Hemi, and the wedges had about 0.95 if I remember correctly. In the 60's Hemi was the king. This was basically because of the well flowing heads. The heads have a huge port crosssectional area and the biggest production valves of any car engines. On a flow bench they can flow a respectable amount of air. However, when the piston with an enormous dome comes close to the TDC, it will restrict this flow a lot. Also during the overlap session the exhaust valve disturbs the flow. The cam and valve sizes must be compromised because of the same thing; when they open they will hit each other. The exhaust ports turn in a production Hemi is really sharp, and it's not that good. Because of the enormous dome needed to reach big CR's the pistons end up to be very heavy compared to a similar wedge. There are no natural quench areas in the heads and need a lot of work to build them, and the end result is not as efficient as in a wedge. The current splayed valve wedges also have the plugs in the center of the chamber and the valves that open away from the cylinder walls, so Hemi has no advantage there either. The engines in the Pro-Stock are highly educated pieces, the wedge technology has evolved a big step from the Hemi days while Hemi technology has not. When they went in to 500 cu in Pro-Stock engines, there were no weight penaltys for the Hemis. Just before that period a Hemi Pro-Stocker actually held the NHRA speed record in pro-stock. But after the big cubes there was no competitve Chrysler Hemis. There were people who tried, but all realized it was not competitive. Ford (=Glidden) run Hemis several years with good success, but also he switched later to the wedges. I don't he did that to give the others an 'edge'. Partially Ford Hemis success and Chryslers no success was because of the engine bore; Chrysler did not have a block that would accept big, currently over 4.600", bores unlike the Ford. ALso the skirt of the Hemi block does not allow a good oil control loosing power. The belief that the Pro-Stock engines wind to 10 000 rpm is not true, at least wasn't two years ago when I was involved with them. The peak power in a Dale Eicke engine was at little over 8400 rpm, the shifts were done at 8800, and it went through the traps at 9200. The car with this engine run 7.17; quicker than any Hemi in NHRA Pro-Stock so far. Currently there is one Hemi Pro-Stocker that I know of, Jeff Wicks Matchmaker Daytona. I believe it's best ET is 7.33, but that may be old information. Anyway he attended a couple of NHRA national races this year and could not make a single pull with a decent ET. He runs his own ways and gets respecable results for the combo, but can not compete against the others, the wedges. Memories are nice and Hemi is a legendary engine, but facts are facts. If you have a normally aspirated engine, the current wedges will outrun a Hemi anytime with a similar port size.

[This message has been edited by DartGT66 (edited December 10, 1999).]

[Maxwedge]

I had read that the main concern with the new hemi was making the piston weigh less, not so much the valve train or any geometry associated with it

[Christopher]

The Hemi pro stock engine of the '70's had to carry 7.25lbs per cid.The wedge and canted valve engines recived a better weight break,I belive the wedges were getting 6.85lbs,maybe less.When you are carrying that much weight,you are going to go slow-period.The Hemi's got down to as little as 366 cid,in order to save weight.The new Hemi is still a Hemi,has a better rocker arm system,doesnt eat valve springs and will perform much better.The 10000 rpm statement came from the Larry Morgan interview in National Dragster.We all know they aren't going to spin that motor to 10K,it was for valve train testing. As far as being copies of GM heads,that's not true either.The heads currently in use are,but not the new Hemi heads.What Chrysler did was combine all the strenghts of all types of heads into one deal.

[JCNathan]

Christopher,

Thanx for the info!!! I just can't believe that a wedge chamber, be it inline or splayed valves can flow as well as valves that are set 90 degrees apart. Fluids move most efficiently when going in a straight line and not have ANY turns. Wedge chambers still do not have the volumetric effeciency that a hemispherical chamber does. PERIOD. The question remains, given that NHRA does NOT penalize hemi99, does the increase effeciency offset the weight of the pistons??
Only a few weeks away from the Winternationals in Pomona -- I'll see if I can have one of my "spies" git some photos of the new engine. I just hope that Nickens boys and DC have them ready. . .

Just a note: new motors, like the 4 valve/cyl 2.5L V6 I have in my Cirrus is a "pentechamber" head. Not spherical at all but has great intake and exhaust "runners". (I saw a head off at my local Chrysler dealer -- way 2 kewl). Even tho' the chamber seems large (relatively speaking), the CR is 9.5:1 and still has essential flat top pistons. Could compression ratio, lightweight piston. I wonder how well my Cirrus will do in Stock Eliminator. Now where did I lay that Stock Car Classification guide???

Later

[PRO]

Gotta add my 2 cents worth,WEDGES SUCK WHEN COMPARED TO HEMI'S PERIOD!!What are the most powerful engines built?Top Fuel,making over 5000 hp,what is it?A HEMI!!Did you know you can bolt a stock mopar 426 hemi crank right in this race block?Its so close to the original 426 hemi design it would blow your mind.Mother MOPAR rules again!!!Did you know you can bolt a 426 hemi crank in most GM Upper class race motors? why do they use a chrysler design?Its better!!Then they put huge letters across their valve covers that say pontiac,chevy,buick or some crap!Yeah the heads are theirs but the blocks are MOPAR design.Have you guys ever ridden in a HEMI car?I"ve had the good fortune to ride in 6 different ones,71 RR which ran 10.40,71 Challenger, 10.10,71 RR-stock,71 Hemicuda-stock,67 Satellite_stock(I know Hemi cars in 67 were GTXs but this one is a pilot car meaning 1st one down the assembly line,it had a 1966 prod. date),69 GTX_modified,every one of these cars left a lasting impression,as theres nothing like a HEMI.CFM FLOW #S prove the capability of the HEMI design head.DLI built a stroked(499)10.25:1 streetable HEMI that made 751 HP!!No STREETABLE PUMP GAS wedge has ever come close!I like wedges and run them but the reality of the bb wedge head is that its the weak link in these motors,(poor combustion chamber design)Things like KBs Hypereutectic Quench domes really help to make them perform better....PRO..

[Christopher]

As far as volumetric efficency,yes the Hemi has the big advantage.There isn't a head out today or yesterday that can match it.NHRA won't penalize the new Hemi.That's where the 500 cid limit came in back in 1982.Now everybody knows that GM stands for "generic motors" 'cause that's what they run.The Olds DRCE engine that WJ had a hand in desingning is basically a big block chebby.Then the cyl head development came in and in order to say you were running a Pontiac with a Ponco engine,the cyl heads had to have a Pontiac part number on them.Same with Olds and the rest of GM.The current Dart cylinder block that both the GM and Mopar camps use was originally designed to be a generic wedge engine that would take a Mopar,Ford or GM head and be used in Pro Stock.I have pictures of the engines that Nickens uses in the Dodges,and have pictures of the engine in the back of their pickup at the Gatornationals.Sorry to say,but the block looks exactly like a GM engine,and the heads look exactly like the current Dart units that are used by the GM camp.When Wayne County used the wedge engine,it looked like a 440,even the water pump was the same as the stock unit.The engine Mopar uses now can be used in a GM car and be legal.

[DartGT66]

I haven't actually dealt with Hemis, I have raced them a few times and won, that's all. The Hemi Landy built made big power in the dyno, but didn't run extremely well at the track. Remember the engine was totally pro built with no money or time obstructions. Still the McCandless built pump gas 499 wedge super bee run over a half second better than the DLI Hemi equipped super bee. That was with less gears and less stall speed. I have a street wedge that runs very low 10's, the engine took about 10 hours to build by an amateur and hasn't been dynoed or tuned after the initial start up. The first time I get beaten by a pump gas naturally aspirated Hemi, I will take my engine to dyno and have it tuned. So far I haven't been even close. At the momoent there is so much more knowledge about the wedges, and so much more parts available, that for power go with the wedges. For looks and image, use a wedge. Add a blower of some sort or nitrous and the situation may change. The reason for this is mainly because the Hemis are less prone to detonation than wedges. This is the reason why you don't see Fuel wedges, they detonate and will not stay together.

[This message has been edited by DartGT66 (edited December 13, 1999).]