blown or nitro

just curiuos why unblown nitro cars are cheaper to run than the blown cars?and also does anyone think that roots cars will be competitive any time soon in nhra.how dangerous are the afd's?please be specific .fuel evacuation?GP

 

A/fuel cars are still expensive to run. The fuel is expensive and you go through alot of clutch parts. When they aren't happy you usually send cylinder heads to Brad Anderson for repairs. I've repaired blocks from alky blow ups and a/fuel blow ups and while any alky one tosses trash all over, I can not believe how badly distorted the a/fuel blocks can get from a serious hydraulic situation. However, when the tune up is right the expense is not so bad. The motor never sees above 6,400 rpm (on our deal) so valve springs last all year. Typically a crankshaft will run all year. Rotating assembly can go 20-30 laps unless something stupid happens.
Top alcohol racing, whether its TAD or A/fuel still has so many costs outside of the parts - travel, truck/trailer upkeep, hotels as well as the parts so that it adds up to a big number either way. I think the only way to keep costs down is to do less races.
I spent part of 2001 working for Chuck Etchells working on Epler's car. The SSI blowers we had made alot of boost, so yes I think they could be competitive. The reason they won't be is because of the upkeep. We would carefully measure the blowers every run for stripping wear and would restrip aprox. every 3-4 runs. A screwblower doesn't change, it will repeat time after time (even after a big backfire), unless something goes through it. That makes tuning a lot easier.
A/Fuel cars can be dangerous. All nitro really needs to ignite is heat and compression. That is why it is so critical to "windmill the motor" (cranking it with a starter with the spark plugs out) so you get all the nitro out. If you turn the motor over by hand, like when adjusting valves and you have spark plugs in which allows a cylinder to build compression, a small amount of nitro in that cylinder can ignite creating an explosion that can blow the cylinder head off the car...it has happened. So great care must be taken and firm procedures established. Of course any race car can be dangerous. I've heard of someone sticking their hand near a running motor and having fingers run between the blower belt and upper pulley, not pretty - I don't recommend it.

Russ

 

Russ- Wow... great answer. I sure did learn something. I do have a question for you though, but I think you have already answered it. If all was equal and you had a choice which would you prefer to run A/Fuel or BAD?

 

thank you Russ ,that was an awesome answer.one more question,what is the hardware i see the AFD teams taking off the manifold once the car is fired?also how many different types of rotors are there for ssi's and do you have to use ssi rotors with ssi blowers ,or do others make rotors that will fit.

 

Gp King, are you plabnning on just match racing, or Running NHRA events? May as well get a PSI, much less headaches and work! Not to mention the performance!

 

TAD vs. A/fuel
At this point I would choose a/fuel because I believe your cost per run is less, considering the performance you can get out of it.
From a driving standpoint, there is certainly more to do in an alcohol car. Before Gregg went to a/fuel he drove a pro mod car and has told me that the excitement driving was at a higher level with the pro mod. The thing about a/fuel that gets me is the way it exercises your brain, I call it the ultimate rubics cube (not sure of the spelling). Probably the same thing that gets the Top Fuel tuners hooked. Personally, I'd prefer to be in an alcohol funny car from a driver's perspective.
What is seen being removed from the a/fuel cars when they are started is a small alcohol tank. It is safer to start on alcohol (top fuel cars are primed with gas and fed gas until running on nitro - but they have a blower that helps prevent a cylinder from filling with fuel). A/fuel cars have a set of nozzles in the top of the intake manifold where you gravity feed alcohol into them. The motor is started on that alcohol, the volume of fuel is controlled by a barrel valve on the tank so you can adjust it to get the right rpm until there is enough heat in the motor at which time the driver opens the fuel shut off to start the nitro going into the motor. Once on nitro the alcohol tank is removed and the driver pulls forward to do the burnout.

 

Sorry, forgot about the rotor question. In the roots blowers the rotors are usually matched to the case. I suppose different rotors can be installed but it should be done by the manufacturer. I believe they are all brand specific.

 

If a guy is running a roots blower on a conservative tune-up for match races, does he still have to re-strip the roots blower every couple of runs or is the re-stripping just part of the deal when running a roots combo? Also, what does a roots blower cost compared to a PSI?

 

We run a roots-blower B.A.D. combination with a 511 cu in. motor. At the beginning of the year we bought a brand new Littlefield roots blower with the Kobelco rotors in it, same one most of the IHRA Funnycar guys and gals are using. And even though we only run match races mostly up here in western Canada and Western United States we still make a few passes a year. So far we've made 11 runs this year and we're just going to re-strip it now for our next race. Have been making between 38-41 psi of boost every run, whereas with an older SSi roots blower we ran a few years back we had to strip it nearly every 4 runs to keep the boost that high...and it didn’t even make that much boost when fresh, I think we saw 40 psi out of it once at sea-level.

We run our car on a conservative tune-up and it usually does quite well on parts. The quickest we've run is 5.988 @ 227, which is pretty decent for us, there is still more in it without hurting parts.

The cost of parts is quite a bit less, as the roots isn't as hard on most things like the crank, rods & pistons (we only run it to about 9300 RPM), and for sure burst panels...in the roots you only have 1, whereas in a screw you have 2...twice the bang-twice the money in a screw for panels.

And as for stripping, we usually only replace the teflon strips during the season, unless the nylatron is really bad. If it isn't we just do that at the end/beginning of the year, and for us we have a machine shop literally in our back yard so we can do all our own machining to turn-down the nylatron strips whenever we need to replace them.

 

Roots Vs. Screw:
We had a Whipple on the car when we started. NHRA put an end to that. But we had no problems with the tune up changing because of changing boost. The screw was real hard to see around though (TA\FC). The Tune up came with the motor when we bought it from Bartone. When we switch to the Roots to run IHRA and Booked shows we got a good deal on a SSI-D fuel blower. We had to redo the fuel system and cam timing. The best money I spend was to send the fuel system to Aaron Sipple for a tune-up. I found it is a lot cheaper than block and heads. We found that feeding a good amount of gas on start-up make the strips last alot longer. But you still have to look at the boost and keep after the tune-up. We have had boost go down 5% and realy screw us up on the rich side.

 

KingNitro,i plan on running ihra ,udra,hopefully with Gods good grace nhra div3.and im trying to gather as much info as possible before i jump in with both feet and find the waters too deep.ihra udra,do not allow screw blowers,but nhra allows roots(although they are not super comptetive except if its on Manzo's car).i thougt the screw blowers break more parts (i could be way off base, i have no experience with them)compare costs for new -used screw and roots if you will. im looking for the cheapest way to go really,really fast.and please dont say stick a bomb under my butt and light the fuse.(lol) hey Nathan.nylatron?turning down? machining ?please explain.GP

 

GP, Randy Goodwin had a PSI with over 200 runs on it! If you try both a PSI and a Roots for a few races each, I Promise you'll never go roots again!

 

KingNitro ,@ what cost.could you compare cost new- used .roots vs.screw.thanx.and compare parts attrition on a mild tune.this is great info guys , a "newbie" like myself needs this and i cant thank you enough.

 

Hey Nathan,how much on average do you get for match racing per run i know its a financial question so your more than welcome to say non of my business.sounds like you got a good deal going .and when you say easy on parts whats the cost per run.if you dont want to post it here email me .

 

A new psi is around $9200. A good used one is gonna be $7800 to $8000 or so. you may find some cheaper but usually they are older upgraded ones. Not sure what the latest Roots blowers go for but i think around $6500. The guys i know that have them say they can go a whole race without stripping them. roots cars are generally a little easier on parts than screw cars but you will not be competitive with one in NHRA.

 

gpking,

The teflon strips in the roots blower are the white ones that seal rotor-to-rotor, and the nylatron are the black strips that seal against the case. The nylatron strips are a harder material, and are also more difficult to change.

Like I said, the nylatron strips need to be machined down after they are installed because they come really tall, and you wouldn't even come close to getting the rotors back in the case. So you have to stick the rotor in the lathe after installing them to machine them down to the proper height, which is all dependant on how tight you want your blower.

We get a lot of customers in our shop in the back yard to re-strip blowers because we've been doing it for years and have the machinery to do it but there are also those who decide to send the entire thing back to Littlefield or whatever manufacturer to get the blower freshened.

I believe we got our new Littlefield for around $6500, and yes they new Littlefield's are really good in that they don't have to be re-stripped as often.

The financial end of it is really up in the air, it really depends on what track we are racing at. The details I don't really want to post, but if you're getting around $750 Usd. a pass you're doing OK. But as I said it all depends on the track and your situation.

This season we have 11 race-meets/match races booked...up here in Canada the season is quite a bit shorter because of all the snow so we never really get going before the end of May, and then finish at the end of August.

The cost per run of our car is rather low because we run on a very tight budget, and have little to no sponsors, which makes it really hard seeing as we're not independently wealthy. I’d say that running at the 6.0-5.9 level which we are currently at we can run the car for $700-$800 a run, including parts attrition and fuel, oil, etc. We are only able to this because of our long time experience in the sport of alcohol dragster racing and our manufacturing capabilities. My grandfather, George Sitko, builds mag drives and other racing components for many of the top teams in the U.S. and helps us out a lot with engines and everything related to the car. To sum it up, we wouldn’t be able to do what we do with what we have if it wasn't for our experience and resources, however non-financial they may be.

 

thanx for the info guys ,i gotta go, heading to florida friday .see you in two weeks.

 

gpking, if going to run a funny car, you can certainly run a roots blower. It will give you more options on where to race here in the midwest.

If you are going to do the NHRA stuff only, then don't waste you time and buy a PSI.

As far as roots blowers being competitive. You could qualify at most of the NHRA races with a funny car, but in TAD you are going to be .10 to .30 away from qualifing. Marty Thacker was able to be competitive with his roots, but had to go with the PSI to run with the big dogs of the class.