Nitrous + Converter

Discussion in 'Race 400/430/455' started by Buicks4Speed, Oct 31, 2002.

  1. GS Kubisch

    GS Kubisch THE "CUT-UP" BUICK

    Check out
    I just read an article about a variable stall valve body they're using in some Nitrous/Supercharged 7 sec cars.
    This might be excactly what you need.
  2. Buicks4Speed

    Buicks4Speed Advanced Member

    Choices, Choices...

    I've talked to some people that have used it and it seems to work pretty good. Just like the stall on a converter though, it varies according to application. I just need a converter tight enough to use it on. i might just go to a lock up or Neil Chance. A Neil Chance with a FB variable stall is what I'm looking at right now. I need to see how the car works with a nitrous cam first. More to follow.:stmad: :stmad: :stmad: How long before you try a little NITROUS????
  3. Buicks4Speed

    Buicks4Speed Advanced Member

    Nitrous Torque!

    OK heres a little something to add/think about. You tend to hear going up in cam size and going to wider lobe seperation with nitrous when dealing with race applications. along with aighter converter. A main reason for this is because how the math works out. Think about......What is Horsepower? it is torque multipled by rpm. Right? So what is a 200 hp shot of nitrous at 3000 rpm? 350 ft lbs of torque, and sometime more. Get the picture. In a curtain sense you can only make use of so much torque in the lower rpm ranges so you want to look at your combination and what your rpm range is down the track. You should try and change your converter, cam, and/or gearing to make a nitrous combination work to its potential if you want your fastest times to be on nitrous. THe cam and converter are the hardest thing to get to work correctly since its not an exact sience and there are alot of variables. Tire size, rpm range, vehicle weight, converter, amount of nitrous; all changes the combination. I hope this helps..... :TU:
  4. texas ranger

    texas ranger One riot one ranger

    Rick, along the same lines I' ve been researching converters and everybody I've talk to BTE ,Protorque,PTC,Coan and Trans King.
    tell me to go with a converter with a steel stator. looking back at your post on your converter It looks like yours doesn't have a steel stator. And if it does could I get by with a quality converter without one.
    By the way how many 9 second mid to low 10 second buicks with trans brake or nitrous without a steel stator converter out there. please share your set ups and save me from making a costly mistake.
  5. Buicks4Speed

    Buicks4Speed Advanced Member

    NO steel hear

    I don't run a steel stator in My Buick and I never had a problem with any of my converters other than the stall being incorrect. I can't say where the limit is. I dont think you need a steel stator converter unless you plan on running 8's. Running 10's is easy on spray even on a street setup. 9's aren't too far out of reach but low 9's and 8's is where it starts getting interesting. What is the race weight of your car? That makes a big difference. I would definitely go with a 10" unless your under 3000 lbs. 10" are more affordable and will more likely stay within a Buicks rpm range without over stalling but they "hit" a little harder which can make it a bit tricky to launch on a small tire. You can get them set up to be a soft hit converter for nitrous which is the way to go. ATI and Coan are very knowledgable on setting up converters and would probably be a good place to start.
  6. stagetwo65

    stagetwo65 Wheelie King

    I've gotten three Coan convertors over the years, and they are top shelf. All three have been steel stator. Two were 8-inch versions and my latest one is a 9-inch. Nothing but good feedback from my end.
  7. texas ranger

    texas ranger One riot one ranger

    Thanks, Rick I was thinking that I could get away without one I think all the companys are trying to get me to over build so that I wouldn't have to worry about it. But as Doug put it, The next step is top shelf also top shelf money.
    I was thinking of going with a 9.5 billet converter shouldn't be much difference from the 10 inch just more efficient. My car is 3450
    with me in it. will be knocking of another 150 to 200 lbs shortly.
    Doug thanks for your input with your car you need that steel stator. I was looking back over some of my Torque tech, torque sheet articles I will be at the level you were some ten plus years ago.
    If I'm lucky.
  8. Buicks4Speed

    Buicks4Speed Advanced Member

    Maybe Later?

    I can't see any down sides to a steel stator other than cost. But stall can be adjusted by a stator change and if you spend alot before you know the "perfect" set point on your converter I'm sure an aluminum stator is cheeper to change and you can go to a steel stator later. Talk it over with who ever you decide to have to build your converter and see what they have to say.
  9. texas ranger

    texas ranger One riot one ranger

    Thanks Rick never looked at it from that angle. makes a lot of since.
  10. Buicks4Speed

    Buicks4Speed Advanced Member

    Ok, It's someone else turn to do a little trial and error. I can't be the only one spraying a fast Buick around here?
    I can't believe I'm the fastest 10.5 tire nitrous'd Buick around???:Brow: If I'm not, this is a forum and your suppose to post that stuff....Its too expensive to learn all this stuff by myself. It would be different if we were all running in a Buick Race class against each other then I would have to put out a bunch of B.S. to slow you guys down. :laugh:

    For all you anti-nitrous guys I will have to say, I have not had one motor related failure from nitrous. Even when i ran it on a stock bottom end and fel pro's.
    The Main Problems I've seen with nitrous motor failures:

    #1 *Not accepting the limitations of how much a given combination will use/take. whether it be a 150HP shot or 300, street motor or race motor. If it stop's going faster with more, than THATS YOU SIGN-STOP! There is a given airflow limitation to each combination that will limit the amount of nitrous the motor will use effectively. A GENERAL RULE OF THUMB: naturally aspirated cams are only good for @125-200HP shot. If you want to go faster, more isn't the answer. You need to adjust your combination and cam to accept it. Unless you like fireballs and carnage. Its the imbalance of airflow that causes the problem not so much the HP.

    * Not taking out any/enough timing. Biggest problem with over 10.0 comp on street motors and 12.5 on race motors. Lower comp on either is alot more forgiving. The more cranking compression a motor has the more attention you need to pay to timing requirements. Nitrous loves low compression motors!

    * No fuel pressure safety switches. Good fuel system or not, things go wrong. Whether is not enough or pressure falls off from a jetting increase or you have a dedicated fuel system and the pump stops working for whatever reason.

    Nitrous is good,........People are bad.:spank:
  11. cray1801

    cray1801 Too much is just right.

    Time for more upgrades...

    Rick, good to see you posting again, are you home? Anyway... since I've moved (late January) and now I've finally received the cash from the old house sale (2 weeks ago), I need to consider my next Skylark projects for my happy 4000 mile 462, before all the $$"s goes to furniture.

    The last time I went to the track was last ~Nov. to Farmington with Jim L. When I saw you last, I was running the 350 at Fayetteville, I was running 14.2's now I'm in the 12.70/8.10 range on street radials with the 455.

    Planned upgrades (next month or so), are MSD 6AL, poly bushings front and back, and a more accurate than stock tach., after that.... maybe some laughing (gas). I'm running the SP-1 and Q-jet on a 10.4:1 C.R., TA-413 motor with Hypers. The dynamic compression is lower than I expected due to the late IVC event with the 413 so detionation has not been a problem with ~25 initial and 34 max. timing.

    As far as fuel system I've gone electric with an Aeromotive unit, 3/8" in with a 5/16 return line regulated to ~6.5 psi at the inner fender, I'm also using a high flow FRAM canister filter at the tank and stock filter at the re-worked 800 cfm Q-Jet. What would be a good next step?
  12. bobc455

    bobc455 Well-Known Member

    Couldn't agree more, Rick.

    I'm nowhere near your level of speed, but I do have a 2-stage system (presently at 100+150HP, jettable to 150+300HP). I'm probably about 450HP wihtout the bottle. I've been using it for about ten years.

    You do have to build the engine to the HP level- if you are gonna make 750, then you have to have internal components strong enough for 750HP whether it from a big cam & heads, nitrous, a turbo or a blower (with slight variations).

    In addition to the items you mention, you have to have quality components (solenoids, etc.) and they have to stay in good shape. A leaking solenoid can hurt a motor too.

    Frankly, I don't understand why more people (street or strip) don't run it. Especially us street folks- you can build a fairly tame motor, and make "bananas" horsepower with the push of a button. Ever been at a stoplight next to a Mustang? After you blow him away so bad that he doesn't know what happened, you'll see why it's called laughing gas.

    Same for a serious racecar- you can certainly get plenty of HP out of a motor, but your cam can only get so big and your heads can only flow so much. Eventually you will need a power booster (blower, turbo, nitrous, whatever) (yes, I realize that we may be exceeding the capability of the block at this point). And nitrous is certainly the one I would recommend. (Not to mention, it can be done really stealthy).

    Unlike you, I admit I have ruined motors- twice. But, like you said, it was utter carelessness on my part- none of the components failed, but the user did. Pure stupidity. As long as you use half of your brain, you will have no problems.

    -Bob Cunningham
  13. Adam Whitman

    Adam Whitman Guest

    hey guys,
    I'm having a problem with my low pressure cut-out switch. When I hit the juice, the initial pressure drop creates a momentary cut-out of the engine. It creates an on-off cycle that sounds like I have a progressive controller running the system.

    I switched to a return-style regulator with no or only slightly better results. The rest of the system has it's own tank and a holley red pump.

    Also, it appears I'm getting air from the fuel pump someplace; I can see it bubbling up from the return line in the fuel cell.. Anybody ever have this happen? The best explanation I can think of is the pump seal is allowing the pump to suck air? It seems worse as I turn the fuel pressure up.

    Also, How far below the fule pressure of 5 psi should I set the cut-out?
  14. Buicks4Speed

    Buicks4Speed Advanced Member

    Not back yet. Electric fan, 950HP Holley. Ignition, buy the MSD multi function box. It plugs right into any MSD 6 series box. Going to a muti function box will save you alot of money in the future and you can tune your timing curve to match. Its everything you need in one box.
    What was your cranking compression when you checked it? If it was low thats a good thing if your looking at nitrous. That cam your running is a little small for a BBB and builds cylinder pressure fast at a low rpm with nitrous which is hard on head gaskets. If you have close or over 200 you need to be careful. YOu can keep your street manners and still go bigger on the cam. Or with the multifunction box you can just take out a little extra timing between 3000-4500 to fix it.

    You cut off switch should be fine if its adjusted to 5 psi. The Holley red pump is preset a 7 psi which I feel is your problem, it needs to be at least 9 depending where the pump and fuel cell are. I know they make a replacement high pressure spring for the Holley Blue but I'm not sure about the Red. Its cheep and they sell it in the Summit catalog. The Red pump may have the volume but it doesn't have the pressure to overcome the initial surge when the solenoid opens.
    Where do you have your dedicated system at? Up front or in the rear. It makes a big difference how much fuel pressure you need.
    Where do you have the safety switch mounted? IT should be mounted on the regulator or "T" 'd off the line going to the solenoid. It can give you surging problems if you mount it directly at the sloenoid. Your safety switch is doing its job. :TU:
    Let me know.....
  15. bobc455

    bobc455 Well-Known Member


    The blue pump will fit right in place of the red pump. That should be able to hold pressure much better than the red pump.

    The pressure of your fuel system depends on your manufacturer- different nitrous suppliers want different pressures to go with their system. It is very important, since when you open the solenoid there is an instantaenous pressure drop, which drops further than it will be under steady-state conditions.

    Do you know what "water hammer" is in your house (when you turn off a faucet and the pipes bang because of the pressure pulse)? You are seeing the opposite affect. That is why I don't ever purge my nitrous line- I like the nitrous flow to be a bit low at first, so the fuel pressure stabilizes and I don't have a quick lean condition (it only takes a single lean combustion cycle to break a piston).

    Also remember that placement of your regulator should be as far forward in the car as possible- during hard acceleration, the pressure at the rear of the car is higher than the pressure at the front. The pressure difference is small, but not insignificant. Therefore the 7PSI from the red pump might not be enough to be able to sustain good pressure when you blast the solenoid open.

    Also, consider a progressive controller (but use solenoids designed to be pulsed, not these crap ones that are standard on most systems).

    On a return-style regulator, remember that the gasoline is flowing through the regulator and being heated. Some components of gasoline (which is a mixture of about 175 different ingredients) start to boil about 120 - 140 degrees, so if the fuel is being heated during it's journey to the engine and back, some components might start to boil. That's no problem, though, because once it goes back in the "cool" fuel cell, it will all recondense and re-equillibrate to normal gasoline.

    If you think that this is a problem, Summit sells a fuel line cooler that can help reduce the fuel temp on the way back from the engine to the fuel cell. Look up Flex-a-lite's P/N 4136 (I think this will work-

    I'm not promising these are all the correct answers, just food for thought.

    -Bob Cunningham
  16. Buicks4Speed

    Buicks4Speed Advanced Member

    Pump specs.....

    A red Holley pump only flows 23 gph at 6 psi. There's no upgrade spring for it to boost the pressure. A Blue or black pump would work. A blue pump flows almost 100 gph at 6 psi. Big difference for only $10. You should have went BLUE.:spank: THere are other pumps to choose from but this is just for quick reference.
  17. Adam Whitman

    Adam Whitman Guest

    I think maybe Rick got the answer right out of the chute. The hobbs switch is mounted just before the solenoid. Should I move it to one of the spare ports in the regulator?

    The system is a Nitrous Works and the recommended pressure is 5 PSI. The regulator is a Mallory.

    The fuel cell is mounted up front, fed with 1/2" line to the pump and 3/8 for everything else. The pressure regulating spring in the pump has been shimmed tight. I have a Mallory pump I might rebuild and install, although that means building new brackets and all that again.

    I had/have a progressive controller. It crapped out on me about the 3rd time I used it. The programming side went goofy (I didn't wire it wrong and burn up the amplifier). Because I've had it a couple years, Holley so far doesn't seem to interested in doing anything about it, even though it's only been used a couple times. I sent it to them, and will report to the BB and anyone else I know how they deal with it. I have a feeling I have bought my last Holley product, but maybe they'll work with me on it.

    As for fuel temp, I don't think it's a problem. The same problem exists hot or cold.
  18. Adam Whitman

    Adam Whitman Guest

    I had the red, so that's why I went with it. I didn't cheap out this time, honest!
  19. bobc455

    bobc455 Well-Known Member

    Well since the pressure in the fuel line is higher than atmospheric pressure, if there is a leak then the fuel will flow out (on to the ground or something). Air won't flow from a low pressure to a higher pressure.

    I still suspect you are seeing something else, not air.

    Also, in theory, remember that if you are supposed to run 5 PSI and your switch is set to 5 PSI, then as soon as you hit 4.999 PSI it will shut off and wreak havok. I might try setting that for 4.75 PSI or something- it should still have sufficient fuel delivery to prevent damage, but won't go on-off-on-off. Just a thought.

    My preference is to have the switch in the same line as the fuel going to the solenoid- that way you know the pressure is being measured where the fuel is going to the engine, and there is no chance of an incorrect reading. If you "T" off the line to the solenoid, like Rick suggests, that is probably ideal.

    -Bob C.
  20. Adam Whitman

    Adam Whitman Guest


    I've set the switch as low as 4 PSI.

    Another thing I forgot to mention is that I have one of those ford-type screw-in filters (1/8" NPT x 5/16" inverted flare) right before the solenoid. Maybe it is too restrictive, although one would think if it would supply a 302 then it would be enough for at least the 75 HP shot I'm giving it now.

    As for air in the pump, a pump (at least an industrial water pump) can suck air while pumping. remember there is a low pressure created on the suction side of the pump. I've never seen this with a fuel pump, but then again I've never looked. The other thing that gave me this idea is that it appears to be leaking fuel around the shaft at some, but not other pressure settings.

    Also, the switch is teed off of the solenoid feed, currently after the fuel filter mentioned above, right before the solenoid. My thinking being exactly what you mentioned.

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