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  • Users: patprimmer
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  1. patprimmer

    Position of oxygen sensor in exhaust

    I have become involve in tuning older Hondas by replacing a chip in the ECU with a rewritable chip or with a real time emulator where fuel and ignitions maps and quite a few other parameters can be altered to re-tune to optimise a different set of priorities and/or for significant changes to the...
  2. patprimmer

    Twin Charging a Honda CRX

    I having a moment of madness and considering twin charging a 1988 Aussie model CRX. Aussie model has the DOHC D16A8 engine and factory A/C and P/S both of which I must retain. The plan would involve a second hand Toyota SC14 roots type blower. I already have a turbo being a brand new Garrett...
  3. patprimmer

    Wide Band O2 sensor response to missfire

    In another site we have a debate going on about a miss fire where a rich mixture suddenly shows lean on a wide band as it loses power for a short interval then shows rich again as it regains power. This is during a dyno tune on a Honda with a roots blower. They are trying to decide if it is...
  4. patprimmer

    Calling a spade a #$#@@ shovel

    In some of my posts here some seem to get their knickers in a knot for directly calling something exactly and bluntly what it is rather than sanitising it. In the code of ethics thread by tctctraining, I just called using market knowledge gained from your employer theft. Let me make it clear...
  5. patprimmer

    Liquid LPG conversion on small 4 valve motor

    Franz I have a car I am restoring and I am considering an LPG conversion. We get a government rebate of A$2000 here for the conversion. I really want one fuel only system and probably liquid injection. Can you recommend a list of possible equipment suppliers. The car is a 1988 Honda CRX and...
  6. patprimmer

    Cracks in sidewall of tyre

    In a post I read today in a thread in this forum I saw mention of sidewall cracks in the rubber. This got me thinking about similar but more critical situations. I have seen some run drag slicks with cracks in the rubber near the bead and parallel to the bead. These tyres had some use but still...
  7. patprimmer

    Very Agressive Profilef Camshaft Break In

    I have been asked to advise oil or oil additive selection to improve break in performance for cam and flat tappets. The engine is being built for an engine performance competition conducted on a dyno. The competition calls for best average power over an rpm range of 2500 to 6500, so it needs a...
  8. patprimmer

    Blower gear oil

    I work on a few blown alcohol injected drag race engines. The gear box on the blower to drive the rotors needs oil to lubricate it. Some are trying to convince me I should use 2 stroke oil as if the oil leaks past a seal and contaminates the fuel, 2 stroke is designed to burn. While I agree...
  9. patprimmer

    Oil pressure problem

    This is not work related, but is really getting me down. If anyone feels it should be red flagged, then fair enough. I just built a 409 CI SBC for my very good friends social ski boat, being the boat I regularly ski behind. It has been nothing but trouble in many areas and with several changes...
  10. patprimmer

    Sensitivity of power to change of a:f ratio

    These question just came up in another forum I frequent. "Is there an optimum a/f ratio for horsepower? If so, is it variable as a function of rpm, compression ratio, ignition lead, combustion chamber design, flame front properties, etc? If there is a range for optimal horsepower, how much...
  11. patprimmer

    Extruded nylon net

    I have a project that requires an extruded nylon net. It needs to be a bi-axially oriented or square net. The function is a rip stop located between the layers of a laminate of two co-extruded films, one being MDPE/LDPE and one being Pa/MDPE/LDPE Size of the window is not all that sensitive...
  12. patprimmer

    Tension vs torque

    I am out of my area of expertise, so the question I am asking is simplistic and only requires a simplistic or rule of thumb answer. Also, nothing will fall down if I get it wrong, it will simply mean things will wobble around a bit and bolts will need to be tightened more regularly. I an...
  13. patprimmer

    Acetone and/or water as a fuel additive to methanol.

    richdubbya I am particularly interested in your comments if you care to read this, but I also welcome comments from anyone with real data rather than speculation. I am involved in the tuning of a drag race car. It has a SBC motor with a Roots blower and mechanical fuel injection, as is very...
  14. patprimmer

    Light Weight Material for Disk Brake Rotors

    I am interested in the carbon/carbon rotors or other lightweight solutions to reduce rotating mass in a drag race car. I know carbon/carbon are used in F1, so should be durable enough for a drag race car, and should significantly reduce the inertia of the wheel hub assembly. I guess I will...
  15. patprimmer

    Road Safety, car design vs driver skill vs legislation vs cost benifit

    A recent thread about some guy trying to justify disabling his ABS lead to the above topics being broached in an ad hock manner. I have seen over the years many opinions and some statistics on the complex issues raised above. I have serious doubts about some opinions and data, and wonder what...
  16. patprimmer

    Charts for Yeild stress of Bolts

    Charts for Yeild stress of Bolts. I am trying to determine the minimum size ARP2000 or similar quality bolts I can use, for a 4 bolt con rod design, which is being used to substitute for a 2 bolt design useing 1913 vintage 5/8" UNF bolts. A chart that shows root dia or min cross sectional...
  17. patprimmer

    Roots Blower efficiency data

    I have a dragrace car with a GM, Roots type blower. It is a 671 at 14% overdrive at the moment In trying to figure the efficiencies of extra O/D, I had the following thoughts. The power to drive the blower faster will increase this is because it is spinning harder. The friction on the blower...
  18. patprimmer

    Airbag trigger points

    Does anybody here know the forces necessary to set of an airbag, or more to the point, the safe limit in use, so as to avoid accidental discharge. The reason for the question, is that on a recent trip to a desolate area of outback Australia, I assisted a mid sized 4 X 4 bus which was bogged...

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