Turbo top fueler

[ramathorn]

Hello, new here although Ive been reading posts and threads at these forums for quite some time. Just been wanting to know something. Instead of just running blowers, how come they dont do turbos and blowers in top fuel?

And when they say a turbo can only support a certain amount of horsepower, does it stop there and anything else above that it will explode? Couldnt you for example take 2 88`s, put em on a 500 ci hemi on nitro and get well above what the turbos are capable of without them failing?

[PrecisionTurboMustang]

I am pretty sure it was tried and they were banned.........

[gryphon68]

Hello, new here although Ive been reading posts and threads at these forums for quite some time. Just been wanting to know something. Instead of just running blowers, how come they dont do turbos and blowers in top fuel?

And when they say a turbo can only support a certain amount of horsepower, does it stop there and anything else above that it will explode? Couldnt you for example take 2 88`s, put em on a 500 ci hemi on nitro and get well above what the turbos are capable of without them failing?

Yes, they are banned.

When someone quotes horsepower, they are really quoting mass air flow and the the horsepower obtained when that air is combined with gasoline.

[Bowtie Guy]

May I ask why they were banned? Too much power? Or safety issues?
Bowtie Guy

[ramathorn]

Thanks for the replies yall.

Gryphon68, does that mean you COULD take them above the supposed "limit" and they(the turbos) would still operate reliably, everything else not worried about?

Anybody checked out Bob Norwood? 4 cyl 4.8 liter ~4000 hp, twin 88mm turbos, 4 valves/cyl, fuel injection, running on a nitro/meth mix.

Supposedly able to do mid 5s at 250+ but no runs have been recorded.

[CW25]

4000 hp on twin 88s. Hmmm doubt it.

[1BadV6ThirdGen]

http://www.turbomagazine.com/tech/0202tur_norwoods_racing_funnycar_integra/index.html

[93yelLE]

4000 hp on twin 88s. Hmmm doubt it.

Nitro though...

This is interesting...first time I'd heard of a Donovan 4 cylinder - thanks for pointing this out.  Learn somethin everyday.
 

[ramathorn]

Ive been searching around and I guess there isnt a limit on what a turbo can put out? For example, on the website turbonetics says the 106 has a max of 2200 hp, but that 1984 vette with the 106 that is street driven and runs 6s has 2400 hp and its very reliable.

Please inquire, I am very curious about this question if any that turbos can make more hp than theyre rated for and do it reliably? Or not?

[Injected65]

Ive been searching around and I guess there isnt a limit on what a turbo can put out? For example, on the website turbonetics says the 106 has a max of 2200 hp, but that 1984 vette with the 106 that is street driven and runs 6s has 2400 hp and its very reliable.

Please inquire, I am very curious about this question if any that turbos can make more hp than theyre rated for and do it reliably? Or not?

What Vette are you referring to?


Answering the questions though, the NHRA has them outlawed (IMO) because they do not know w whole lot about power adders besides roots/screw blowers.  Anything that is not familiar to them and is not able to be tech'd easily they are generally leery of and will usually outlaw them.  When you start talking Nitromethane most of the information out there is on screw/root blown applications.  Nitro is not a forgiving fuel to be testing new combo's with so few people with turbo's have ventured there.  There was however an announcement this week of a new twin turbo ADRL car that will be running a small dose of Nitro this upcoming year.  As far as the power rating, again there isn't much info out there on turbo combo's running Nitro.  So... what the max they will make is yet to be determined in the real world.  Calculations could be made given the airflow that the particular turbo is capable of combined with the BSFC of the nitro motor its being ran on, but not much real world examples to back the calculations up.

Chris

[Horsewidower]

Gale Banks experimented with a Top Fuel turbo dragster.  If I recall, they had a lot of trouble getting the car to hook up when the turbos spooled.  The NHRA ban stopped any more attempts. 

[Ugly_On_Purpose]

nevermind...

[ramathorn]

Not sure of the owners new name, but the builder was Lee Howie. One of the fastest street legal cars in the states.

Surely if a old blower can do 7000 hp then a good single 115mm or so turbo would be more than enough right???

[gryphon68]

Gryphon68, does that mean you COULD take them above the supposed "limit" and they(the turbos) would still operate reliably, everything else not worried about?

The difference with nitro-methane is that it contains a large amount of oxygen in the fuel, so its like adding even more air than the supercharger or turbo is capable of.

The compressor side of a turbo on a nitro engine would not work any differently than a turbo on a gasoline engine, it would still operate within the limits of its compressor map.

The turbine side might have to tolerate higher operating temperatures, but that's easily within the ability of more exotic materials.  The amount of fuel being burnt (lots) would probably involve selecting a larger turbine than a typical gasoline engine.

To compete in today's nitro classes your would need two very big turbos, two of the new 114mm monsters might do the job, but it might require two larger (much larger!?) custom units, think billet everything.  Titanium compressor wheel, Inconel turbine wheel.

[ramathorn]

Is there not a limit to the superchargers capabilities?

[Injected65]

Not sure of the owners new name, but the builder was Lee Howie. One of the fastest street legal cars in the states.

Surely if a old blower can do 7000 hp then a good single 115mm or so turbo would be more than enough right???

Is there not a limit to the superchargers capabilities?

The blowers that the TF and FC guys are running these days certainly aren't your "daddy's old roots blower".  They have hundreds if not thousands of hours of design time in them.  The blowers are very high tech as to the rotor design, rotor to rotor clearances, housing design, etc.....   You talking about a blower that can go from 0psi to 40-50psi (maybe more) in only tenths of a second.  I doubt that there is a single automotive turbo made that could match the airflow output of these large blowers and definitely couldn't match the blowers in response time. 

Chris

[ramathorn]

Dang, thats cool man. I guess you`d need something along the lines of a 190mm inducer with around a 2.80 or so A/R?

I imagine a beast like that even on a 500 ci hemi with a high CR that it would still have pretty bad lag.

Also, do any racers outside of top fuel use 14-71s? If so I bet they have a monster of a car.

[wannarun]

Someone already trouched upon the subject, but maybe I can elaborate some more. Gasoline stoichometric air:fuel ratio is 14.7:1. That is 14.7kg of air to 1kg of gasoline. Now on to nitromethane, this fuel's stoichiometric raito is 1.7kg of air to 1kg of fuel. This means the gasoline engine requires 9 times more air than a 100% nitromethane engine. Now we all know that our engines make more power when you go a few points lower than 14.7:1, but this is just for comparison purposes. Nitromethane has a lower energy density than gasoline or methanol; meaning it takes more fuel to create the same energy output of gasoline.  There will still be plenty of issues to deal with. Not all the fuel is burned in the combustion process, as can be seen from the flames coming out of the TF or FC headers. The exhaust temperatures are going to be much higher. The turbine housing would need to be very very large to handle the lb/hr of exhaust gases. So in short, MO is the tricky part is dealing with the shear volume and temperature of the exhaust gas. Getting the required amount of air into the engine will be a sinch.

[esteinmaier]

Traditional turbo design just doesn't tolerate the pain of niromethane very well.  First, there's the EGT.  The metal alloys just can't handle those temps all the way down the track and not start to melt.  Easy solution is to use metal alloys with higher melting temperatures.  OK, that's fixed.  Now make a turbo large enough to actually become helpful.  They really aren't made.  Nothing out there really flows enough to support 7000hp.  So you do a couple huge turbos, and you're getting close, but you would need 4 of them to really work right.  Now you're into such a complex design that you've wasted a ton of time when there's a blower out there you can bolt on and go just as fast.

[Drac0nic]

As stated, I suspect that you don't really flow that much air due to the nitro. A 14-71 blower flows 3400 CFM at 20% over drive from what I can find, not sure what speed a top fueler runs but if we correct that to lb/min that's 234.6 lb/min. Considering you can get a 75mm S400 and it flows 90lb/min each, quads would not really be all that essential. On the other hand the turbines may be another story entirely. You may have to do something like ceramics to get those to work right, and they would need to be absolutely massive in size. Even by the AFRs alone, you're almsot producing double the weight of exhaust gas, much less any chemical reactions that take place to expand the molecules and in turn the volume of this fuel or the temperature increases.

[RyanMayo]

From the article linked:

But what do turbos do when you put all that burning hell spewing out of a nitro motor through a turbine section? "If you want to build a motor to make a lot of heat," says Norwood. "Use gasoline. Nitro doesn't burn as hot. Nitro's a 'dead' fuel with lower BTUs and much lower energy per gallon. I've made gasoline motors live with 1,900-degree exhaust heat. Nitro? It's just fuel. What's the EGT? I'd guess they run 1,300-1,400 degrees, but they typically have so much fuel burning in the headers of a blown-fuel engine, who can tell? Everybody thinks because there's a big flame coming out the exhaust it's gotta be real hot. That doesn't mean anything. The nitro just can't burn fast enough on a blown fuel motor. Why they're so loud is it's still burning when the exhaust valve opens. So they make a big bang and shoot fire out still burning."

Thoughts?

[ramathorn]

Very interesting stuff. 230 lbs/min is quite freaking massive. 14-71 blowers are awesome.

I know Mike Moran runs in pro mod and he makes 3500+ hp with twin 91s.

[xr8tt]

I wouldn't say the turbo would be slower to respond!!
It's done in different ways.. 2 step, launch control etc..
A engine way smaller capacity can easy run 7's  as in TJZ and 20B rotor..
Different class and regs ..
It's a little to do with sponsors!! The traditional sponsors are NOT into turbo's..
They where regarded as rice power adders..
This car is in Australia now.. Or its older brother..
http://videos.streetfire.net/video/Worlds-fastest-2JZ_59711.htm
Remember these engines are 3.0 6 cyl..

[ramathorn]

Yes those are impressive engines. The 2JZ is a masterpiece in its own right. They can take so much power its unbelieveable.

But anyway, was wanting to know if the only way to make a turbo operate more efficiently at high psi is to make it bigger? Like could they for example take a 91mm and specifically design the turbo to be able to operate efficiently at like 55 psi?

Or would you just have to go bigger to get that?

[PrecisionTurboMustang]

Very interesting stuff. 230 lbs/min is quite freaking massive. 14-71 blowers are awesome.

I know Mike Moran runs in pro mod and he makes 3500+ hp with twin 91s.

Turbonetics 122mm turbo is siad to flow 250lbs/min+........

http://www.theturboforums.com/smf/index.php?topic=119440.0