Quote: "Hmmmm . . . let's see, now. How many twin screws or roots are competitive at a national level? Could the answer be . . . why, yes it is . . . ZERO." End Quote




Maybe that's because they're superior? When's the last time you saw a piece of **** outlawed? As I recall they (twin screws) are outlawed in NHRA pro classes. Top Fuel uses Roots, not centrifugal. I would say that is competitive at a national level.

........and btw, those beloved procharger numbers put out on the 03 cobra, are about the same numbers the twin-screw 03 cobras are putting out at similar boost levels, but the twin screw makes way more power down low....and if you think torque down low has no meaning, well go tell that to a big block guy.

 

You are right about "national level." I should have been more precise. I meant pro-am stuff like NMRA.

Top fuel is irrelevant. Roots are the only allowed blowers. And things like blower efficiency don't matter much where, even running super high octane nitro ****tails, they detonate so badly that the plugs are consumed by half track. Top fuel is top fuel.

Of course low-end power matters. And mid-range power. And upper-range power. My point was just twofold: (1) low-end power matters only on the launch, and (2) more power right off idle is not a necessarily a good thing in a traction-limited application.

p.s. -- torque is a static measure. It is always horsepower that moves the car. When most people talk about "torque," they are really trying to express than an engine makes lots of HORSEPOWER on the lower end. Torque = force. Horsepower = force per unit of time = work. Work is what actually creates the velocity.

 

tim I love your wheels but your lecturing too much!

 

You are right. I'm sorry.

I guess that I'm still PO'ed that my "who wants a $4K centrifugal" thread went down the toilet so quickly -- and venting in this thread. I just grow weary of the same old BS.

I'm now stepping down off of of the stump and shutting up.



. . . for now

 

Jay sure did.......

Guess who's ported Eaton he is running right now

..........well at least until spring when his new KB goes on.

--Joe

 

i don't think anyone is stupid enough to compare cents with eatons. We should all know well enough by now that while the eaton is a proven blower, it has it's issues, namely heat. The twin screw vs. cent is another issue.

My guess is that the cent will, (actually has, isn't that really fast 1st gen a dual cent?) prove itself to be an excellent quater mile contender if not the more superior one. I personally would be a little more concerned about streetabliity. Not in terms of how capable and how quiet it is, but simply in terms of mashing my foot on the pedal and feeling that instantaneous go. Will cents be able to provide that? I always kind of thought of eatons and twin screws are nearly violently powerful blowers while cents and turbos are more smooth but excessively powerful.

Also how loud are cents overall? at idle at full throttle.

 

also a centri might be more for Tim's application, considering he doesnt drag race (much if at all), when hes running the corners hes already got some rpm running to help with a bit of lowend loss. i cant wait to see what these blowers will do though. when will someone put an ati f-4 on

 

Tim is correct about hair dryers making more power. but after having a Mustang with a Paxton then a K/B I enjoyed the torque curve on the K/B much better. The Paxton was great on top end and soggy on the bottom. The K/B was unreal on the bottom, but seemed to not have quite as much on top. This was a total street car and was not reved much over 5600 or so. It did not matter if you were in the wrong gear with the K/B as it was a torque monster. I am sure that on a dragstrip,it would have been a different story. They both are great units, just different. Skip

 

Easter- I have my opinions you have yours, Like I said Im sure a Centri will make a great race truck blower but as for street, its going to be a pooch. Put the pedal to the wood at 3000RPM on both trucks and you will see what I mean. I think you also know what I mean otherwise you wouldnt have to run N20 to get the truck out of the hole. Thats my opinion, your opinion is the Novi is a great and your going to use N20 to overcome the blowers weakness(This is my point). This isnt a slam or a flame but I race and have raced in organized classes and Dual poweradders are not allowed in anything but brackets or backroad country tracks. If you use a each blower as it was designed for, on a street/strip truck as ours, the Eaton/KB/Whipple will always win.


Tim- Lets not be confused here, You cant compare a Pushrod motor(Your Procharged Suburban) to the mod motor. To start with that engine NA makes way more HP and TQ than our 5.4s, therefore it wasnt as big a slug out the hole and the motor itself could get the truck going and use the blower to continue in the upper end.

We each have our opinions and Im not trying to force mine of either one of you, If you prove me wrong I will be the 1st to say congrats. However having worked with Mod Motors as well as racecars, the centri will only dominate in a topend charge and for what 99.99% of us use our trucks for, the Roots/Twinscrew is best. A Centri is RPM Dependant, boost goes up as impellar speed goes up. A Roots has 90% boost at 2500 and works is way up as you go.


Skip- What you say is the exact thing Im saying

 

I just wanted to say I have playing around with my truck to find out what the problems are with it so I can tune it.
1. The blow off valve is just too close to the mass air meter. So that means I'll probably go air to air intercooler so I don't have that problem and so that I can still have a nice BOV to atmosphere. Right now I have disabled the BOV.
2. I have a 2600 stall torque converter from PI a 3" upper and a 9" lower pulley. I can step on the gas and roast the tires. I haven't checked boost at redline, but at around 4500 rpms I am at 25psi boost. Somehow I don't think power is going to be a problem.

 

easter
At what speed can you do a tire roast ??

And how is the SCT stuff coming along ?.....you must be getting used to it the truck sounds mean.
Dale

 

If your not going to do a simple head unit replacement with proven and cheaper existing choices, why not ..........

"get off first and or finish first"

......... go Whipple 3.3 or TWIN turbos

.........everything else is a compromise.

 

There must be something wrong with the data collection equipment.

There is no air-to-air intercooler on Earth that can take the charge from even a perfect 15 PSIG compressor and cool it to within two degrees of ambient. You would be talking intercooler effectiveness numbers of near 100%. The very best are in the high 80's. Even numbers in the low 90's are highly suspect.

Have you run these charge air numbers by ATI's tech staff? At those boost levels with a 3-core, you should be seeing 25-35 degrees above ambient.

 

Why couldnt you get a sheetmetal one. Im sure those are much cheaper. Reichard Racing custom fabs sheetmetal intakes. Check out on the web page and then "Custom Engines" or whatever. One guy is TT and the other guy is blown, I believe they both have Sheetmetal Intakes. I wouldnt think they would be that expensive to fab up. Procharger uses sheet metal intakes for the 03 Cobra kit

EDIT: Pics to better illustrate my point:

 

Those blowers are by far the most ineffecient out there. Its no wonder the Hemis need 500+ HP to run them. Just imagine how much power they would make with a Twin Screw or a Centri . Sure they make a ton of power off of the Weilands but the parasitic loss is amazing