Pro Mod engine choices... (1 Viewer)

[Bill]

I have become enamored of the Pro Mod racing that is going on at selected NHRA events, and am curious about one of the technical aspects of it.

The dominant performances by the R2-B2 cars in the last few races would seem to indicate that the turbocharged cars have a horsepower edge over the others, as evidenced by their MPH superiority.

I went to the R2-B-2 website and was mildly surprised to learn (through the pictures) that the powerplants in those cars are "semi-hemi" G.M. engine designs, similar to the D.R.C.E. powerplants used in Pro Stock.

They obviously work exceedingly well with forced induction, making tons of horsepower.

My question is this: Given the track record of the 426-Hemi based Mopar-design engines that have proven to be formidible in forced induction venues (such as Top Alcohol Funny Car,) is it POSSIBLE that a Hemi might be even FASTER in Pro Mod with turbos than these Rat Motor derivitave engines, or would they already be using them (Hemis) if that were true???

I don't see anythng in the NHRA rulebook designating a "spec" engine block for this class, so I was just curious as to whether the Hemi was even a possibility for powering these cars. Not everything is in that rulebook....

I certainly don't suggest that ~I~ have a "better idea" than Steve Petty (he's a genius, I think) when it comes to making these cars go quick.

I was just curious; you don't see any G.M. motors in TA/FC, and the concept is pretty much the same for the two classes, it looks to me...

Anybody got any good information on this?

I am (obviously) in the dark....

Bill, in Conway, Arkansas

 

[Buns]

Hi Bill,

I, too, am enamored with Pro Mod racing. I've been a huge fan of doorslammers since Pat Musi, Tony Christian, Mike Moran and Bob Rieger were duking it out on the NMCA circuit.

I'm a big turbo fan and remember scouring the internet for videos of Bob's S10 and '57 Chevy's that were running turbo power. He was whipping up on the competition back then.

As far as Hemi combo's, Brad runs Hemi heads on his '68 Camaro. His car was lethal, last year. So that's certainly a proven combination.

It would be interesting to see Precision Turbo and AJPE team up on creating an NHRA legal Pro Mod engine. PT Turbo's with AJ Hemi power would be something to see.

Steve Petty, as you said, is a genius and has Turbo Wedge power pretty much cornered. The El General turbo car he was crew chief on just won at the Shakedown, this past weekend, on its first race out. Pretty amazing.

Here's a link to the press release on PLR's site. The 481X turbo engine is about as powerful as it gets.

El General and Larry Wood Win at E'Town! - Pro Line Racing

 

[Rat]

Hi Bill,

I, too, am enamored with Pro Mod racing. I've been a huge fan of doorslammers since Pat Musi, Tony Christian, Mike Moran and Bob Rieger were duking it out on the NMCA circuit.

I'm a big turbo fan and remember scouring the internet for videos of Bob's S10 and '57 Chevy's that were running turbo power. He was whipping up on the competition back then.

As far as Hemi combo's, Brad runs Hemi heads on his '68 Camaro. His car was lethal, last year. So that's certainly a proven combination.

It would be interesting to see Precision Turbo and AJPE team up on creating an NHRA legal Pro Mod engine. PT Turbo's with AJ Hemi power would be something to see.

Steve Petty, as you said, is a genius and has Turbo Wedge power pretty much cornered. The El General turbo car he was crew chief on just won at the Shakedown, this past weekend, on its first race out. Pretty amazing.

As someone who was in the stands for it I have to say the car was an animal, It looked as if driving that car would never be a dull moment.

 

[Buns]

As someone who was in the stands for it I have to say the car was an animal, It looked as if driving that car would never be a dull moment.

Jealous!

I would love to be at the Shakedown. A doorslammer racing fans dream race.

Steve Petty is a genius. It's amazing how smooth and consistent those cars are when everything goes according to plan.

 

[twostep]

As soon as NHRA allowed the use of torque converters in ProMod, I knew right then the turbo cars were instant competitors. They still lag a bit in the 330' compared to their supercharged and nitrous counterparts, but the once-huge difference is now comparatively minor. What's not minor is the back-half charge coming from the turbos.

Why wedge over Hemi? Just a guess, but there's most likely a lot more data available for the wedge combinations...that, and financial considerations. BAE Hemi engines are a bit costly.

 

[Bill]

Thanks to all who responded! I really appreciate all tht good, insightful, information!

Now, of course, my imagination's running wild... LOL!

New technology is what drove drag racing for many years.

This is a breath of fresh air, in today's cookie-cutter-car environment.

I'm gratified to see it.

Bill, in Conway, Arkansas

 

[Toejam]

I have already heard that NHRA is considering another Turbo rule change for the GSA Pro mod class. Thing is; will it even matter? They run 88's now, would cutting it down to say 82's make that much difference?

 

[DrRocket]

Maybe my memory is faulty (Maybe??) but weren't "Olds" engines the combo to have in supercharged TAD's some years ago???

 

[Les]

Maybe my memory is faulty (Maybe??) but weren't "Olds" engines the combo to have in supercharged TAD's some years ago???

Blaine Johnson won his TAD championships with the Olds wedge head combination.

 

[Wes]

The 481X style heads have amazing flow numbers and they are a bit lighter than a comparable Hemi head. Another neat feature of that motor is the external mounting flanges on the block. They are GM up front and either GM or Chrysler in the rear. Gives a chassis builder more flexibility when designing the car for a particular engine/trans combo.

A happy turbo motor is all about CFM of air delivered to the throttle blades through the intake and into the ports...where the pressure is created (flow + restriction = pressure). Having virtually infinite design choices in turbine and compressor wheel design, downsizing of the turbo inlet doesn't always have the effect of power reduction. In some cases it can actually improve efficiency.

 

[Bill]

Blaine Johnson won his TAD championships with the Olds wedge head combination.

Not to be a nay-sayer when it comes to TAD history, but the "Olds" engine in Blaine's car MAY have used something other than the "assembly-line" Oldsmobile-design cylinder head.

Let me clarify that contention, please:

Warren Johnson had a deal with Oldsmobile back in the eighties (not at all sure about the time-frame) in which Warren acted as a consultant (and, more) on a cylinder head project involving the improvement of a big block (canted-valve) Chevrolet Rat Motor (396/427/454) head. How that Chevy head ended up in an Oldsmobile research project, I have NO IDEA....

But, when the dust settled, Warren came out of that program with an "Oldsmobile" cylinder head that was in reality, NOTHING like any Olds head ever produced, but was in fact, a much-improved version of the aforementioned canted valve, big-block Chevy head. It "fixed" a lot of the problems inherent in the design of the Chevy head, and I THINK, was pretty much responsible tor the improved version in use today, and was called I think, the "D.R.C.E." head.

I believe that THAT was the head on Blaine's successful car; not an actual "Oldsmobile," true-wedge head.

If I'm wrong, somebody please correct me.

Back in the '60s, though, There WERE successful fuel and gas dragsters that used complete Olds engines with good success; (Bob) Creitz Automotive, Ratican/Jackon/Stearns, Porter-Reis, the Burkholder Bros, Adams/McEwen,
and some I can't remember...

One-by-one, the participants and supporters of the wedge engines were forced by the reality of Hemi horsepower, to abandon their G.M. and Ford powerplants, and join the ranks of Hemi power, but the canted valve Rat Motor hung on for a lot longer than most.

"Semi-Hemi"... what's in a name????

Apparently, quite a lot, in this case.

 

[Toejam]

Blaine Johnson won his TAD championships with the Olds wedge head combination.

I thought Blaine ran the Wedge motor for only a few races? The advantage was the 3.7 lb. Per cube rule versus the 4.4 lb. The Hemi's had at the time. Rick Santo's ran his SBC Dragster as a wedge to get that weight break!

 

[Bill]

I thought Blaine ran the Wedge motor for only a few races? The advantage was the 3.7 lb. Per cube rule versus the 4.4 lb. The Hemi's had at the time. Rick Santo's ran his SBC Dragster as a wedge to get that weight break!

To muddy the water a bit more; NHRA recognized the advantages of canted valves (over a true wedge design,) and in some cases, had THREE weight breaks for competitors; one for true wedge engines (wherein the valves are all on the same plane,) one for canted valve wedges, and a third for Hemis.

Is it possible that the 3-weight-break scenario was in place during that period?

I dunno; just sayin'...

 

[Les]

Quote:
Originally Posted by Les Mayhew
Blaine Johnson won his TAD championships with the Olds wedge head combination.
Not to be a nay-sayer when it comes to TAD history, but the "Olds" engine in Blaine's car MAY have used something other than the "assembly-line" Oldsmobile-design cylinder head.

Let me clarify that contention, please:

Warren Johnson had a deal with Oldsmobile back in the eighties (not at all sure about the time-frame) in which Warren acted as a consultant (and, more) on a cylinder head project involving the improvement of a big block (canted-valve) Chevrolet Rat Motor (396/427/454) head. How that Chevy head ended up in an Oldsmobile research project, I have NO IDEA....

But, when the dust settled, Warren came out of that program with an "Oldsmobile" cylinder head that was in reality, NOTHING like any Olds head ever produced, but was in fact, a much-improved version of the aforementioned canted valve, big-block Chevy head. It "fixed" a lot of the problems inherent in the design of the Chevy head, and I THINK, was pretty much responsible tor the improved version in use today, and was called I think, the "D.R.C.E." head.

I believe that THAT was the head on Blaine's successful car; not an actual "Oldsmobile," true-wedge head.

If I'm wrong, somebody please correct me.

Back in the '60s, though, There WERE successful fuel and gas dragsters that used complete Olds engines with good success; (Bob) Creitz Automotive, Ratican/Jackon/Stearns, Porter-Reis, the Burkholder Bros, Adams/McEwen,
and some I can't remember...

One-by-one, the participants and supporters of the wedge engines were forced by the reality of Hemi horsepower, to abandon their G.M. and Ford powerplants, and join the ranks of Hemi power, but the canted valve Rat Motor hung on for a lot longer than most.

"Semi-Hemi"... what's in a name????

Apparently, quite a lot, in this case.

Sorry I should have clarified that Blaine was not running a 455/425 production type Olds motor. But he D.R.C.E. cylinder head is "Wedge Style".

 

[Mooseman]

Wasn't the Johnson dragster engine the 481x rodeck?

 

[Les]

Wasn't the Johnson dragster engine the 481x rodeck?

It may have been at some point, but he had an Oldsmobile sponsorship at the end of his Top Alcohol Career...so one can assume his Wedge motor was a D.R.C.E. derivative. There has to be someone on the mater board who can confirm this? I do remember the Alan Johnson 526 c.i.d. supercharged D.R.C.E. engine being the hot, blown setup for Pro Modified in the 1990's.

 

[Bill]

Sorry I should have clarified that Blaine was not running a 455/425 production type Olds motor. But he D.R.C.E. cylinder head is "Wedge Style".

Well, it's not a Hemi. for sure, but A "true" wedge has the valves all on the same "plane."

The D.R.C.E. engine is based on the canted valve Chevy big block, in which the valves are "canted," in an attempt to gain flow.

In my mind, this sets them apart from a "wedge" engine, such as an FE block 428 C.J. Ford cylinder head

NHRA apparently thinks so, too, since they have, over the years, set different pounds-per-cubic inch parameters for canted valve engines in various classes.

As you said, they ARE a "wedge," but not a "true" wedge.

Bill (splitting hairs, again... sorry)