Turbos in Pro Mod (1 Viewer)

[Bill]

Can someone who is familiar with the technical aspects of Pro Mod engines and their history answer just two questions for me, please. Since it looks like Pro Mods MAY be a part of NHRA's program for a while, I am curious about the viability of various types of forced induction that might work well with the large, alcohol-fed powerplants some of these cars employ.

The NHRA Rulebook; Logic takes a holiday....

To wit: It seems that turbochargers might be a good choice for these cars, but will turbos work well with large-displacement Hemis? I see on page 185 that they're limited to one 120mm unit, or, two 91mm units. hmmmmm.... then, they give them a 123 cubic inch advantage over a Roots blown car... What are they thinking? It would seem at first blush, that two 91mm units would move a LOT more air than one 120mm unit, but maybe not.... I dunno.

And, my second question is: What does this mean? On page 185, under "Superchargers," the rulebook says, "Intercoolers, variable multi-speed supercharger devices, turbocharger(s) prohibited in both classes." No more "Chase Knight?" Is that what they mean?
Or, is this about Dale Armstrong's variable-speed blower drive he developed for Kenny Bernstein, only to have it outlawed by the tech gurus at NHRA...
Or, both????

And, they BAN screw-type superchargers. I cannot imagine why, unless they're trying to protect the captive business of some friends who run Roots-type blower-manufacturing and rebuilding services. What other reason could it be?

Guess that's more than two questions; sorry....

But, can anybody shed some light on this mess?
Any information or opinions will be appreciated.

Thanks in advance.

Bill, in Conway, Arkansas

 

[Doug in the woods]

I may be wrong but I think a turbo charger produces more usable hp than a blower, taking into account a blower requires alot of hp to turn them.
The maintence costs I think the blower costs more?
screw type blower are a better blower but ???
I do know for sure that a between round thrash, a blower is easier than a turbo = less plumbing

 

[Wes]

A turbo doesn't really care how big or small an engine is. What it wants is strong exhaust velocity and pressure to spin the turbine to in turn spin the compressor to make substantial boost. As far as turbo sizing goes, again...it's not all about how big it is but the aspect ratio of the turbine and compressor housings, the design of the impellers, and how efficient the unit(s) are.

Turbos are indeed easier on the basic engine. The boost is delivered in a smooth, constant fashion. A roots supercharger delivers the boost in a pulsing manner. The same pulses are transmitted through the crank snout as well. In most cases, a turbo engine is operated at a much lower RPM range than that of blower motor.

Maintenance can be a breeze if the turbos are mounted out of the way. The ducting comes off easily and, in most cases, once you've got that out of the way the basic engine looks like something out of a Super Comp dragster.

I checked the rules revisions on NHRA.com and they have ammended the use of intercoolers. Turbo cars will be allowed a single intercooler.

Ask Mike Moran if a big inch turbo motor can make power. 6.01 @ 250+ in an old Pro Stock Monte Carlo. If they ever get that car to ET well in the first 330, Scotty Cannon's "Outlaw" 5.70 passes are going to look silly.

 

[Toejam]

Turbo's make a lot of power no doubt about it, but as a spectator they are boring as hell! If it wasn't for the Popping on the line you wouldn't know they were on the track. Like watching Hair dryers.

 

[nedannouncer]

Boring as hell yep....jeez.

Watch Andy Jensen make laps in his turbo Camaro, the front wheels are barely skittering along the pavement over the entire 1/8 mile.

Then there's Frank Pompilio's Mustang pulling the wheels in the traps. This is incredibly boring stuff...pass the no doze.

YouTube - Frank Pompilio - 6.90 @ 230 mph


Brian

 

[Toejam]

Boring as hell yep....jeez.

Watch Andy Jensen make laps in his turbo Camaro, the front wheels are barely skittering along the pavement over the entire 1/8 mile.

Then there's Frank Pompilio's Mustang pulling the wheels in the traps. This is incredibly boring stuff...pass the no doze.

YouTube - Frank Pompilio - 6.90 @ 230 mph


Brian

I didn't say they didn't make HP, I just hearing my Racecars! If I want silence I just turn the Volume down on TV! NOT!!!!!!

Look if a Turbo gets your Rocks off go for it, doesn't do it for me is all!

 

["Chuck"]

I didn't say they didn't make HP, I just hearing my Racecars! If I want silence I just turn the Volume down on TV! NOT!!!!!!

Look if a Turbo gets your Rocks off go for it, doesn't do it for me is all!

With all due respect, have you seen what the turbo guys are doing in the comp classes? theyre running 255-257 mph over there with turbo powered engines.

 

[Bill]

Well, I am going to ask this again, since it sort of got buried in the comments about other facets of turbo motors;

I asked.... "will turbos work well with large-displacement Hemis?"

If anybody answered that, I must have missed it.

I'm primarily curious about why they haven't been used extensively in Pro Mod racing.

Anybody know?

 

[Toejam]

With all due respect, have you seen what the turbo guys are doing in the comp classes? theyre running 255-257 mph over there with turbo powered engines.

CHarles, re-read my post.

 

[BlueStangGT]

Well, I am going to ask this again, since it sort of got buried in the comments about other facets of turbo motors;

I asked.... "will turbos work well with large-displacement Hemis?"

If anybody answered that, I must have missed it.

I'm primarily curious about why they haven't been used extensively in Pro Mod racing.

Anybody know?

Bill, I think the answer may be, "good question". It appears that the giant displacement isn't necessary with the turbo motors, the fastest guy (I think) is Mike Moran at 250 + mph with about 555ci wedge head motor. Not sure who the fastest hemi turbo is... maybe Brad Personett? Smaller V8's have been pretty spectacular... John Mihovetz has run in the low 6.30's at 221mph + at 2600 lbs with a DOHC 283ci Ford... I guess that's sort of a hemi. Check out this thread:

TWIN TURBO HEMI vs TWIN TURBO WEDGE : and the winner is.... - Yellow Bullet Forums

 

[Bill]

Tom,

Thank you SO MUCH for that link!!! There was a great, 5-page discussion on that forum, with some very knowledgeable people posting, and I learned a lot!

Mostly, what I learned was that this turbo business for big-inch, alcohol-fueled Hemis, is pretty much uncharted waters, and basically there's a lot of R & D going on right now. Nobody seems to have a handle on making the kind of horsepower these things will eventually make because of what we could call "tuning problems" (camshaft design for the turbo motors, and an ignition system that works.)

What works with a roots-blown motor doesn't seem to work well with a turbo.

It would seem that it's just a matter of time before the (many) talented people working on this "tuning problem" business get a handle on it and these big-inch turbo cars start running like they should (F-A-S-T!)

I guess the watchword is, "Stay tuned!!!"

That link you put up provided the answers to most all of my questions. I had no idea they were having such a thrash with these motors.... live and learn, Bill...

I think it will get really interesting in a year or two....

Thanks again!!!

Bill

 

[clutchflite]

I didn't say they didn't make HP, I just hearing my Racecars! If I want silence I just turn the Volume down on TV! NOT!!!!!!

Look if a Turbo gets your Rocks off go for it, doesn't do it for me is all!

I gotta agree - the move to turbos was one of the things that killed the AA/GS cars.

 

[Bill]

>>>the move to turbos was one of the things that killed the AA/GS cars.<<<

I don't remember that.... refresh me, please. I remember (I THINK... it was a long time ago) Ohio George had one, but the Mallicoat's Barracuda wasn't an AA/GS car.... I think it ran B, didn't it?

Who else had one?

It makes me sad that I can' remember this stuff...

I thought the advent of the blown, altered-wheelbase A/FX cars like Mr. Norm's Charger, and Arnie Beswick's GTO (and later, Chrisman's flip-top Comet) were mainly responsible for the demise of the blown Gassers.

But, I obviously missed something, and I'm really curious about who else ran a turbo in AA/GS. I'd appreciate some info about this; I'd like to know what I missed.

Thanks for any information.

Bill