14-71or screw blower?

Hello to all, I am looking at building a quick 16,outlaw,big dog shootout type of car.I am looking to step up my car with either a 14-71 or Whipple/PSI.Which would be the better way to go? I know the roots need to be stripped regularly while the screw blowers dont. How much harder is it to tune a screw over a roots? How much of a power difference?I will be running alcohol,bbc,glide,etc.I can pick up a whipple for a good price but the seller tells me sfi will not certify it.I have also found some PSIs that are not certified but are fairly cheap.What would you run? Screw or Roots? If all else fails I may have to join the turbo crowd.I dont want to have to de that though.

 

Hello Will and thanks for the info. I am running a door car. 3000 lbs. 10 inch tire class. They run at Houston,Dallas,San Antonio,etc.The class is like a fastest street car type. The cars are running 7.50s to 8.50s. Most of the heavy hitters are all turbo cars.I know the turbos make tons of power but i've always wanted to run a supercharger.What about a older PSI will it certify? What shoudl I look for if I decide on a screw blower?

 

100% agree with Will

I ran 14-71 Hi-Helix supercharger on my BB Chevy for a quite number of year in Hydroplane Racing. Probably change teflon strip more than anybody here in Quebec Canada.This year, we run a PSI D supercharger on our top alcohol Dragster and believe me it is a Top of the line piece of equipement . Call Norm Drazy at PSI , he is a real gentleman and by the way he is able to speak a little bit of french with me !!!!

Best of luck.... Serge TAD 182

 

Hello WIll, I have the bbc already and also have a th400 if the glide cant handle it.I'll have to resort to a "filled" factory block,stock port location heads(no big chiefs,etc. allowed),10.5 tire,mini tubs o.k.,ladder bars o.k.,no 4 links,no lencos,brunos,etc.,no tube cars,must "appear" factory,yeah right.The top cars are making about 1800 hp on turbo power at about 350 c.i. pretty impressive I think.What do you think the screw blowers can make on an "average" bbc?

 

I sold my Whipple to a Outlaw guy when NHRA would not let us use them any more. The guy ran a BBC. He found that the manifold became an issue. The The Whipple with it's blow out plate on the side hit the heads. He had Hogan make a manifold (Not cheap). After retuning it for the Whipple he was about .2 faster and 4 MPH. He also said he had less problem with leak down in the front 2. screws put a lot less heat in the front of the motor. You may have to move front and back to get good exaust temps. You also have to put as much less fuel in the hat. By putting it in the manifold you can balance the motor better. Spend money on a tune up. It is alot less the rods and blocks. Try Aaron Sipple in Ky, He did mine and I have had good service with him. Others like Holbrook, Manzo, Hickmen, do it also.

Bob Lupini
Check us out at:

www.ihra.com/profile/funnycar/bob_lupini.html

[ August 14, 2003, 07:29 PM: Message edited by: Funnycarbob ]

 

PS.
Think Lencoglide, the Screw makes a lot more bottom end.

 

Some observations whilst I have coffee:

The 10 inch tire is the equalizer. I would think the trick would be to make power later than at the hit. This is probably why the turbo cars work well.
From my observations tuning both a roots FC and a screw FC,the roots car will run harder to the 330' and have a much quicker 60'. It might be easier to soften the hit on those 10" tires with a PSI without killing the whole run.
Another car I run is a roots blown dragster with a LencoDrive. To give you an example of what you are up against: this car has 34.5 X 16 X 17 Goodyears and the luxury of the weight tranfer of a dragster. Due to the torque multiplication of the converter it had been a bitch to get off the starting line ( it would either .950 or smoke the tire like a fuel car).
I added a ProMag timing controller and this has helped the car quite a bit.
Which ever way you go the MSD Programable timing controller will be your most valuable tool with the 10" tire. Just my opinion.
Good Luck

 

Thanks to all you guys for the info. I must agree that the turbo guys have an advantage as do the spray guys down low. The turbo guys dont bring in all the boost till past 100 foot mark then they really lay it on. Most probably 1.50 the 60 foot then make it all up by mid and top end.Still debating on screw or turbo. I guess if I find a fair deal on a whipple I may go that route or else I may join the crowd,I hate doing that.As far as the trans. goes, they dont allow lencos,etc. I may be able to sneak in a clucthless doug nash though.

 

If this is ok to run,It may be of great help anyway you go.


http://www.moretraction.com/

 

Why not a small BAE engine with roots or PSI?

Do those Turbo cars have traction control? If they are EFI, then I bet they do. That would be another problem you would be up against.

 

I guess it depends what you call "run with down low". We have been as quick as .923 60 foot and 2.46 to the 330. Most of the screw dragster stuff I've seen are in the .900 to .915 at below 2.40 at the 330. I believe Marty Thacker did turn a .909 in a roots....once.

 

Hello,Yes the turbo cars are all running electronic f.i. They control everything with the ecm,timing,boost,fuel,everything.They are all running automatics also.Most of the top cars are making about 1800 h.p. with about 1400 ft./lbs. of torque.They come out of the hole with hardly any boost then thet bring it slow.They make their move about 330 on down.

 

I have a PSI for sale, complete with Norm Drazy's tune up booklet.

EJ Johnston
438tafc@bellsouth.net
225-791-6957

 

I work on a Pro-Mod team and we run a Kobelco fuel blower. We trade a lot of info and talk shop with a lot of the TA guys. I've heard some really differing opinions between the PSI and the Whipple. Just curious what the likes/dislikes are that people have from one to the other? I know in our class the Kobelco's and SSI's seem to be the thing to have and I hear these two are very comparable.