How much difference in high helix blowers?

How much difference is there in different brands of high helix blowers?
Have been looking at Littlefield with K11 rotors and Kobelco.
Are there any major differences, in performance, reliability etc?
Is a delta opening and a pie opening the same?
Whats the difference with a retro case?

Also, when changing to a high helix, would there be much improvement going to a larger hat? Currently I'm running a bird. Would a BAU make a difference?

 

My car is 506 hemi, with clutch and 3 speed lenco, dragster.
It's currently running a std helix 14.71at 50% od. ( this od was what it was setup with when I got it) I think on a std helix it is too much. Would it be using more hp than it's making running it this hard?
The class I'm running is a bracket class, with a bottom cutoff of 6.50. I ran 6.84 last weekend.
I'd like to be able to run 6.50 or better, reliably & consistently. If it will run quicker, I can back down the shift points to get it where I want it.

 

blower

You'll pickup a lot with any high helix retro. IMO the blower is the closest thing to free hp you'll find. Even if you don't spin it hard an effiecient blower will make your combo's life easier.
There are hundreds of hp differences between a regular littlefield HH and a superman type kobelco.
The hat matching the top opening is important also. There's a lot more than "eyeball engineering" going on.
JR at RBS blowers is pretty good with bang for the buck recommendations and comparisons between makes.
I ran a TAFC modified k9 superman with a quadstar mag hat. A lot of people frown on the k9 rotor and nobody likes a ugly mag hat so it was cheap and worked great.
The k8 is a good value also. You can't get rotors anymore so they are low demand but work fine for the average guy.

 

From experience, I would shy away from anything that has a K8 rotor in it.

A few years back we bought a brand new Kobelco Superman 14-71 with K8 rotors, it was the latest greatest trick of the week deal. And while I will say that when it was still in one piece it worked very well, it didn't stay that way too long. The lightening holes at the ends of the rotors are too close to the groove for the teflon strips, and as a result we suddenly after 40 passes had a cracked rotor. Cracked right in the corner of the teflon groove from the end, about 5" long down the rotor. Maybe this is why they aren't available anymore?

We were one of the lucky ones as we noticed a tight spot when turning the motor over and inspected it before our next pass, but we saw a few of the not so lucky ones come apart down track.

Now, as well all know warranty on anything racing related is next to non-existent, but since the blower was only about 40 passes old from brand new we thought perhaps there would be some sort of warranty on the deal. But without going into too much detail, we were told by the manufacturer that this was not warranty, even though we felt it was a design/manufacturer issue, and we needed to buy a new case and rotors. Needless to say we went somewhere else.

 

The Littlefield with K11 rotors looks a nice blower, it's something I am looking to invest in for my car.

May I ask is there a difference between Hi-Helix blowers, and Hi-Helix Retro blowers? The only idea I can think of is the Hi-Helix was the original 120 degree rotor blower, then they developed it into a Retro blower.

I may be completely off, but some clarification would go down very well.

 

Retro is another name for front discharge, we retrofitted a high helix back in the day and that name stuck, our LB-20 is a frt discharge blower, that is designed to go on the original stud location if you so desire

 

If you are looking for a used Littlefield 8-71 Hi-Helix Retro Fit send me a PM or drop us a mail to info@seasideaffair.com. Have one coming for sale soon and also a Hi Helix that is direct availible.

Located in the Netherlands Europe.

BTW the hats are also pretty important for the performance of the blower.

Frank

 

Andy, is that done by moving the rotors back in the case? If so, how far back are they moved from a conventional 14-71.

Tom

 

The LB-20 has an inset front bearing plate of 2", that moves the rotors back but keeps the opening pretty close to stock location, now keep in mind not all manufacturers manifolds are the same, there is a variance of about 200 thousands between them all, another big difference with the LB-20, as with most new blowers nowadays, is the top openings, getting the air in efficiently is very important

 

Maybe the first time it was done was on an old style blower and they retrofitted the new rotors style in an old case....hence the term retro.

 

The high helix came out in the late eighties, shortly after that, it was discovered that a frt discharge worked even better, so customers would send us back their blower and we would "retrofit" it with the new brg plate, and a top plate to close down the opening, and a bottom plate to move it back, hence the name, " retro"

 

What works better? A retro or delta opening.
Is there any sites where I can look at the different styles.

Is it better to move the blower back to get the opening close to the middle of the manifold?

Also, what do the shoe inserts do and how do they fit in?

 

I'll answer your questions as you asked them,

A frt discharge (retro) makes more boost and is more efficient, therefore takes less power to turn, (parasitic loss)

Moving the blower back on the manifold even the amount of pressure in the runners, making the nozzles more even

The shoes in the top, control the top opening size, by which a lower overdrive needs a smaller opening than one turned fast, it's a fine tuning tool

Hope this help clear up some questions, I'm glad to help

 

Thanks for your help Andy.

 

One question for Andy ?

Does a Hi-Helix help in any way below 7000 rpm ?

 

It depends on the overdrive, the critical number is rotor RPM, a high helix won't hurt, at lower RPM, but sometimes there's no need for the extra cost, remember all high helix blowers are billet rotors, certain applications work fine with cast rotors which keep the cost down considerably