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Thread: blower motor

  1. #1
    Junior Member SHOW GUEST
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    blower motor

    :cry: need help i have a blown small block chevy 406 ci. 11.0 comp. 8-71 blower big ugly injection, afr 210 heads, it has in hat it has 37 nozzles and port has 37 nozzles we have tryied by passes from 60 to 105 does not make any differance had pump rebuilt what kind of tune-up is someone else running
    thanks

  2. #2
    Senior Member RACING JUNKIE
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    Set-UP

    Well, the BIGGEST Prtoblem that i see?The Big&Ugly is about Twice as Much of an Injector than you Can USE!It has WAY Too Much Area for that Little Motor.You Need a Bug or a Bird at Best!
    What is the Rest of your Combo,and what are you doing with it?
    Heres my email address if you need any other Help?
    THANKS
    Greg 8)
    gar96tlr@t-one.net

  3. #3
    Junior Member SHOW GUEST
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    the blower is not going to pull no more than the pullies on it is it? last pass last year ran good went 5.60 in 300 ft and coasted through 1/8 this season we added 11.0 comp.mag, port nozzles. made a hit with it about a mounth ago and seemed to do fine but track would not hold and went up in smoke.

  4. #4
    Senior Member RACING JUNKIE fla1976's Avatar
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    Blower

    I understood that blower motors need lower compression, 7:1 - 8.5:1 to be efficient. Think I'd find out for sure what CR you are running. 11:1 is way too high.

  5. #5
    Senior Member RACING JUNKIE
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    Blower

    Actually 11to 1 is Dead ON!
    If thats the Question that you are asking?If you have 11 to 1 Comp.Then you can NOT get any BETTER!
    Years Back,The Cave Men thought that Low Comp.on a Blower Motor was the way to go? WRONG!!!
    Now,if you are Running Fuel?Then you want Low Comp,6.5 to 7.5.
    ALKY 10.5 to 11.5.
    Later
    G 8)

  6. #6
    Senior Member RACING JUNKIE fla1976's Avatar
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    Blower

    This is a little long, but it's good info from Summit Racing:




    Many people have the impression that a supercharger is an exotic performance part found on wild street machines or racecars. There's also the impression a supercharged vehicle is difficult to drive on an everyday basis. Nothing could be further from the truth on both counts
    First, a supercharger is nothing more than a large air pump that can provide greater than atmospheric pressure (boost) to an engine. When was the last time you thought of an air pump as exotic?

    Second, when building an engine for supercharging (other than a racing application), it's generally built for low to mid-range torque and power just as a stock engine would be. Because an engine may be left stock when utilizing a supercharger, your vehicle would be no more difficult to operate or maintain. As you can see, a supercharger isn't really exotic. It's really quite practical.

    The guidelines below have been established to assist in building a basic street supercharged engine. Engine durability and dependability are two factors given strong consideration in these guidelines as current supercharger kits are developed for everyday use. However, superchargers are quite capable of reliable use in competition.

    Engine Preparation

    The extent of the engine preparation will depend entirely on how the engine is to be used. A supercharger can be installed on a stock engine with cast pistons and a cast crank as long as moderate boost (below 8 lbs.) is maintained and any detonation is strictly controlled. Engine speed should also be limited to 5,000 rpm. Detonation on cast pistons can easily break ring lands. Too much boost and/or detonation on a stock or worn engine can cause piston damage or burned valves.

    Most late model "smog" engines work well with a supercharger due to their lower compression ratios and smaller cam profiles.

    Supercharged Engine Guideline

    1) 7.0:1 to 9.0:1 compression ratio: The optimum compression ratio is 8.0:1.

    2) 4-7 psi boost level: This range of boost has proven to be the best compromise for power and reliability.

    3) Engine rpm: When using stock cast pistons, the engine should be limited to a maximum of 4,500-5,000 rpm. Exceeding this limit may over-stress the cast pistons causing failure. Blueprinting an engine using the proper components will allow higher rpm reliability and will maximize a supercharged engine's potential.

    4) Detonation (pinging): Detonation is the single most destructive force in a supercharged engine and steps must be taken to eliminate it. This may include lowering boost level, retarding timing, installing a boost timing master, increasing fuel flow to prevent leanout, and/or using a fuel additive to raise octane level. The cooling system also needs to be in good condition to prevent overheating, which may lead to detonation.

    If an engine is to be driven hard or under load, as in towing, a thorough blueprinting should be considered. Forged pistons, with their inherent strength and ability to withstand higher temperatures, are recommended. Follow the piston manufacturer's recommendations for piston-to-cylinder clearances.

    A compression ratio exceeding 8.0:1 is not recommended, nor is it necessary for brisk performance from a supercharged engine. If raised to this level, fuel, ignition timing, and total boost become critical factors.

    Next consideration would be the piston rings. They should always be the best quality available because the piston rings take as much abuse as any other component in an engine. "Moly" or "Double Moly" piston rings (iron piston rings coated with Molybdenum Disulfide) are an excellent choice for supercharged street engines. They seat quickly and wear well. For hot street or competition, where higher boost will be used, chrome or stainless steel piston rings should be considered.

    Consideration should be given to using heavy-duty fasteners especially on the connecting rods and main caps for added durability and strength. If the engine will be run with a high boost level (12 psi or more), high-performance head gaskets with built in stainless steel O-rings are recommended because they can withstand the higher combustion pressure and temperatures encountered in a supercharged engine.

    Cylinder Head and Valvetrain Preparation

    Weak valve springs or burned valves can lead to backfires. When an engine has more than 50,000 miles on it, inspect the entire valvetrain. If the valve springs require replacement, factory heavy-duty springs should be used. With the use of an aftermarket camshaft, follow the camshaft manufacturer's recommendations for valve springs.

    For proper cooling of the valves, use a three-angle, "street-type" valve grind. With the additional combustion temperatures normally generated in a supercharged engine, the wider valve seats will provide better cooling of the valves, and the three-angle valve grind will provide better sealing of the valves

    When any port work is being done, most of the effort should be directed to the exhaust ports. The supercharger will overcome most minor restrictions on the intake side of the cylinder head.

    The use of O-ring head gaskets requires receiver grooves in the heads and block milled by a competent machine shop.

    Camshaft Selection

    A supercharger can overcome inadequacies in a stock cam up to about 4,500-5,000 rpm. You will typically find that performance with a blower will not be significantly enhanced below these speeds with a cam change. However for optimum performance at higher rpms, a more aggressive cam will provide substantial power increases.

    For best performance with a blower you should look for a cam that has higher lift and longer duration on the exhaust side. Street performance with a blown engine is usually best with a cam that is ground with a 112 to 114 degree lobe separation. Blower cams can be typically run "straight up." Note that a blower has tendency to lessen the rough idle of radical cams.

    Other Preparation

    Air Cleaners: Good quality air cleaners should always be used on a street supercharger. Allowing dirt or debris to go through the supercharger may score or gouge the rotors or case.

    Exhaust System: The less restriction the better. Use large tube headers with low restriction type mufflers. Low speed torque will not suffer by using larger primary tube headers as is typical on unblown engines.

    Carburetion: At full throttle a blown engine can require 50 percent more air than an unblown engine and as a result needs a larger carburetor(s) in order to make maximum power and boost. If your blown engine is primarily driven on the street at moderate engine speeds (under 4,000 rpm) you won't need a larger carburetor(s).

    Typically the carburetors(s) will need to be enriched by 5 to 10 percent on the primaries and 10 to 20 percent on the secondaries. The idle mixture screws may need to be enriched by one or two turns. In either case, the carburetors need to be jetted properly to prevent a lean condition. A lean condition can lead to overheating and detonation.

    For initial start-up, it's better to have a slightly rich condition to help prevent the engine from overheating. After initial start-up, check the spark plugs for proper reading (color) and adjust the carburetor(s) accordingly. You want to see a medium to dark tan color.

    Ignition System: Set the initial timing at 6 to 10 degrees BTDC. The distributor advance curve should be calibrated to give a total advance of 28 to 34 degrees by 2,500 rpm. Most late model OEM electronic ignition systems have the capability of working well with a supercharger. Some distributors with computer controlled advance curve and timing may not be compatible with a supercharger because of the preset timing and sensors they require. Any of the aftermarket high performance standard or electronic distributors should function well when properly calibrated. A quality electronic unit would be the preferred choice for best all around performance and reliability. If detonation is encountered, a boost/retard system that works with manifold vacuum and pressure is recommended.

    Supercharger Drive Ratios

    The reason we cannot provide an exact boost figure is that camshaft profiles, cylinder head configuration, and carburetor size can all have effect on the amount of boost that will be shown on the boost gauge. To illustrate, if you have small port heads and a stock cam, at higher engine rpms the blower will be unable to overcome these restrictions and boost will build up in the manifold producing an artificially high boost reading. Conversely, changing the cam and heads will make the boost reading go down but the power will increase at higher engine speeds.

    Boost is a direct result of three factors: engine size, blower size, and the speed the blower is driven in relationship to the engine speed. Bigger blowers driven at the same speed as a smaller blower will produce more boost.

    Normally decreasing the upper pulley by one tooth or increasing the bottom pulley by one tooth will raise the boost one or two pounds. Conversely increasing the tooth count on the upper pulley or decreasing the teeth on the lower pulley by one tooth will lower the boost by one or two pounds.

    If you desire a substantial change of boost you can just interchange the top pulley for the lower pulley and change the blower from underdrive to overdrive. However, swapping pulleys will approximately double the amount of boost you will get. This should only be done for extreme high-performance race engines by those with substantial supercharger experience.

    Thanks to Holley Performance Products, Inc. for contributing to this guide.

  7. #7
    Senior Member RACING JUNKIE
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    Blower

    WOW!
    Well if thats Not the Most BS i have ever seen?
    I suppose if you want to Supercharge your Stock Camaro,Firebird,or Muskrat.Then you would want to Follow those GUIDELINES???????
    But,with my Blown Alcohol FUNNYCAR i'll stick with the comp Ratio that has been working for me and about 95% of the Guys that have Cars like Mine? 11 to 1.
    Later
    G 8)

  8. #8
    Senior Member RACING JUNKIE
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    Re: blower motor

    edited out

  9. #9
    Senior Member RACING JUNKIE
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    Re: blower motor

    Quote Originally Posted by 8490
    :cry: need help i have a blown small block chevy 406 ci. 11.0 comp. 8-71 blower big ugly injection, afr 210 heads, it has in hat it has 37 nozzles and port has 37 nozzles we have tryied by passes from 60 to 105 does not make any differance had pump rebuilt what kind of tune-up is someone else running
    thanks
    To answer your question without the rhetoric or telling you what we have (which is moot in your request for help)...

    Is there anything wrong with Alky and 11:1? No. Is 11:1 "perfect" for compression? Maybe, maybe not. It all depends on cylinder heads and blower efficiency. There is no perfect compression ratio and all of the current top alky teams that I converse with are running different compressions.

    The big and ugly, while maybe not the best choice, it certainly looks cool as shit, and will work just fine. Change your barrel valve linkage from 1:1 to accelerate the barrel valve open quicker as you depress the throttle. This will compensate for the large surface area opening of the butterflies.

    If you're changing main jets from 60-105 and not seeing any changes in the performance, the tune up is soo far off it doesn't matter what you do.

    Once again, I will point you, like many others, to Bob Szabo's book (I should ask Bob for commission sales)... www.racecarbook.com

    It contains ALL of the formulas needed to setup an alky injected motor, so long as you know what your fuel pump and nozzles flow.


    Without knowing:

    1. CID
    2. Compression Ratio
    3. Blower size/style/stripping/manufacturer (CID if you have it)
    4. Over/Under drive ratio
    5. Fuel pump flowed GPM @ 100 PSI @ 4000 pump rpm
    6. Hat/Port Nozzle Sizes

    I don't know anyone who can spit out the magic tune up based simply on hat/port nozzle and main jet size.
    -WJ Birmingham

    OneBadGMC.com

  10. #10
    Senior Member MASTER BUILDER
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    Here is a solution that we got from Enderle. what is the smallest pill you have ever run? was it smaller than the 60 ???

    Now I know this is going to sound a little off the wall but do you have 2 pills in the fuel system. Meaning have you stacked 1 pill onto the other??

    We've done it and until the guys at Enderle ask that very question we had never even considered it.

    unscrew the jet you have in the holder and take a look to see if there is another hiding.

    If not, take the time and money and have the pump barrel valve, nozzles and pills flowed

    Good luck


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