Supercharging question Rotrex c38-81 vs c38-92/91

Discussion in 'General Off-Topic Discussions' started by skygear, Feb 11, 2020.

  1. skygear

    skygear Member

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    Tearing down the engine to replace the head gaskets. So, while Im in there, figured might as well finally supercharge the engine. URS Mark3 Stage 3 is the plan. BUT, I have had a little experience with friends and helping them install SC kits on S2000's and others. Most used the C38-92 - I liked the 92 because I'm familiar with it.

    Plan for the engine was hoping for +400hp out of this.

    While I'm replacing the head gaskets, I was going to do the timing chain, all the gaskets, thermostat, etc. Clean up the pistons and cylinders.

    What else Should I do while in there?

    Suggestions? Opinions?
     
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  2. mejbro

    mejbro Member

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    Well, if you get the Stage III you don't need to worry about buying a thermostat cuz you'll get one that opens at 160°. Are you pullin' the motor? If so, perfect time to change the clutch / flywheel, TOB, short shifter. Also, when you get the Stage III, you will be getting 2 exhaust cam gears that are paired to your new thermostat and UCON - EMS. You have a long road ahead of'ya. I wish you the best of luck, I loved every minute of it!!!
     
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  3. skygear

    skygear Member

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    Appreciate that. I know whats in the kit as far as components. For some reason thought it was 170º

    Full disclosure. This is on an automatic. ‍♂️ - For now.

    Hadn't really planned on pulling the engine. Not unless I have to. I'm confident I can do all the teardown I need while its in the truck.

    Did you have any experience with the 92? or stuck with the 81? any Piston upgrades, valves, springs, cams, etc?

    What kind of numbers were you getting HP & Torque?
     
  4. NHXRUNNER

    NHXRUNNER "New Hampster"
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    Call URD Tech Support. Dial 3. Gadget is the man you want to talk to. But if the 81 is the blower that comes with the kit, Stage 3 with that blower is 440hp. The 92 leaves room for future upgrades but you’ll be pulling the engine to build the bottom end if you go that route....
     
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  5. skygear

    skygear Member

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    I guess thats more my question now then. 440hp stage 3 with the 81 - If I go with the 92 for now then build the lower end later, will I be able to use the 92 on it with a "Lesser tune" to the ~440hp range, then do the additional build upgrades in the future?

    Would you recommend anything additional on the top end while I'm in there tearing it down?
     
  6. sf.larry

    sf.larry New Member

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  7. mejbro

    mejbro Member

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    With an automatic transmission, you're already ahead of the game. If you look up the leaderboards for fastest TACOMAS, you'll notice that there ARE many automatic Tacomas on the list. Don't worry about having a manual tranny unless your getting a T-56. Don't downgrade to our 6 speed. But don't just build for Horsepower... you gotta get the power to the ground. The Bilstein shocks in the rear gotta go ( 18 way adjustable QA1's will help you squat )and you may wanna use some traction bars to "hook up". Depends on what you're trying to achieve. Either way, there's tons of support on this forum and URD Tech Support is second to none!
     
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  8. skygear

    skygear Member

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    My truck is built up already for more offroad use but I dd it currently. Suspension is icon stage 7 adjustable remote res.
     
  9. Gadget

    Gadget Well-Known Member

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    The C38-91 and the C38-92 are the very same supercharger with the only difference is the inlet. The -91 is 3" and the -92 is 3.5" and necks down to 3". The perform the same.

    The -91 bolts right up to the URD supercharger kit and if you want the -91 instead of the -81 we can certainly do that. We just install one size pulley larger on it to get you started.

    My last dyno on my truck was with the -91 and made 540 RWHP with an 80mm pulley and an aggressive tune. My normal street config is the standard tune with a 75mm pulley. This is with a built engine.
     
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  10. NHXRUNNER

    NHXRUNNER "New Hampster"
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    There you go, right from the horse’s mouth.
     
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