zguy95135 Posted January 10, 2004 Share Posted January 10, 2004 i have been putting my manifolds back on and i was wondering if the heat shield between the intake and exhaust is really necessary. Will it cause the car to get heat soak (more then usual), if so can that be fixed with a manifold blanket thing (MSA)? are there any dangers of taking it off? btw i used the search function Quote Link to comment Share on other sites More sharing options...
240zprace Posted January 13, 2004 Share Posted January 13, 2004 i'm not using mines with an N42 intake manifold on a turbo motor. i dont seem to notice any hi-heat temp changes at all Quote Link to comment Share on other sites More sharing options...
gramercyjam Posted January 13, 2004 Share Posted January 13, 2004 Absolutely necessary on my car - it has headers and triple webers. Without a heat shield the fuel will start boiling out of the carbs after about 30 seconds of hard driving and flood the engine out when idling. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 13, 2004 Share Posted January 13, 2004 Gramercyjam--do you have insulators between the carbs and the manifold? Seems like your carbs are WAY too heat sensitive. I had vapor lock with the SU's at one point, but never with the Mikunis and I've been out in 114* heat (but I'll NEVER do that again). FWIW-I haven't gotten around to making a new heat shield for my Mikunis, but I had a good one on my SU's that I made. I don't honestly know that there was too much of a difference. Much bigger gains were made when I removed the mechanical pump and the metal fuel rail, which were both heating up the fuel a lot. That solved my vapor lock problem with the SU's, which I only had on one occasion at Streets of Willow when it was about 105*. Jon Quote Link to comment Share on other sites More sharing options...
gramercyjam Posted January 13, 2004 Share Posted January 13, 2004 I have two sets of insulators between the manifold and carbs - the old thick red phenolics and a new black plastic O ring set. Mine are old Weber 45 DCOE's. I wasn't getting vapor lock. And I couldn't reproduce the condition on the street or in the garage, I just couldn't run the motor hard enough or hot enough. The flooding only occured during competition, and only when I happened to stop on course or at the end of the course. My heat shield is nothing fancy - just a piece of .030 aluminum with the edges folded over and a longitudnal bend for stiffening just big enough to shield the carbs from the headers on an "H" shaped bracket attached to the intake manifold. It sure made all the difference on my setup. I'm just running the stock electric fuel pump (no mechanical) and a cheapie purorlator fuel pressure regulator on "3" without a return line. My carb setup requires very little fuel pressure. Quote Link to comment Share on other sites More sharing options...
Guest Boyd Posted January 13, 2004 Share Posted January 13, 2004 I put my heatshield back on and did notice a difference. I was running N42/N47 combo with T3 at the time. Adding the shield made a big difference. I was actually able to put my hand on the intake after driving it hard or in the summer heat of Alabama. After I added the Spearco intercooler, it stays very cool. My intake air temperature sensor reads typically within 10-15 degrees of the ambient temperature, but it is located just before the TB. FWIW - Regardless of what engine combo you are running, I would get some shielding in there. I have considered adding the thermo wrap in addition to the shield for added protection. Remember, cooler air = more dense air charge = MORE POWER! Quote Link to comment Share on other sites More sharing options...
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