looking into nitro

Discussion in 'PSI Superchargers Tech Questions' started by 1320motorworks, Sep 4, 2021.

  1. Bob69

    Bob69 Member

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    I am contemplating replacnig NOS with a Nitro system as the cost of NOS is stupid expensive downunder. Running a carb.
     
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  2. 1320motorworks

    1320motorworks New Member

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    thanks for that info!!! on the compression side of things, how much is too much? building an aluminum 540 with 12 to 1 comp. I've waited to try the 20% nitro till I got some stronger parts as i was on the edge with the current setup.
     
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  3. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    You need to study the blow down procedures of an A/Fuel car and stick to them religously. A motor with the compression of a N/A motor will blow the heads off - and I mean that in a quite literal way - with a few drops of nitro that may happen to drip into a cylinder or be left over from a run.

    You will need to remove all 8 plugs, disconnect the input to the nitro system, blow the nitro system down to get all the fuel out of it, then "windmill" spin the motor over.

    I think it could be pretty dangerous to try to run a separate nitro system without these procedures.
     
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  4. aj481x

    aj481x Member

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    Good advise, separate systems are really dangerous. I have witnessed heads completely blown off.
     
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  5. Floyd Stringer

    Floyd Stringer New Member

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    As I have been dabbling in the expensive stuff on and off for years (unblown), my best success was 28% on a 433 BBC. Gained .3-.4 in the quarter the motor loved it, and we never hurt so much as a spark plug ground strap. But my question to you all is this: on a dedicated nitro motor, what is a good bore/stroke combination? Long stroke/small bore or larger bore/shorter stroke? Seems I remember reading years ago about the benefits of long stroke/low r.p.m. A/FD motors so as not to out run the flame front in the cylinders, no? What is the setup on todays current crop of cars?
     
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  6. Dave Koehler

    Dave Koehler Member

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    Since you, in your other thread insinuated the word budget you should be aware that the only thing that makes the current A/F cars "budget" is that there is no blower.
     
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  7. Floyd Stringer

    Floyd Stringer New Member

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    Thanks for your insight. Can you help with any information pertinent to my question about current A/FD bore/stroke combinations? Thanks
     
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  8. chutedragger

    chutedragger Member

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    I run a 392 ajpe A/F deal in heritage series. 468 ci. 4 5/8 stroke, 4.060 bore. This was Gene Adams combo. 11.6 gallon pump. 100%, and the whole pump into the motor. We can not hurt this thing! 70 degrees in the mag! (44) It loves 7300 rpm. Started at 10.3 and up to 10.7 compression for our Bakersfield tune up.

    Gene is a very smart man. He put this combo together (and shared it with everyone) to have a class where guys could play and not break parts. He figured out the fuel volume, piston speed, rpm…and came up with a pump size that worked. That’s the trick.

    We had never run fuel prior to this set up. 50 laps, one pinched ring trying to find the “spot” with a high speed! 1 rod bearing, idling it too slow! That’s it! We leak down, and check the bearings every lap.

    The class ran away into the 5’s with a fuel pump change (or lack of change)…but if you look at the class back 10 years ago…nobody broke anything!

    The disclaimer, we were all running ajpe or Brad blocks and heads…so tough stuff, but you only buy it once.
     
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