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Discussion Starter #1
I just installed 55mm 300zxt TB in my 78 280z. Now, It's really slow getting up to 2000rpm (rich?) and after it's real smooth til 5500rpm. But right before 5500rpm it bogs. It feels like rev limiter!!!! (lean?) I plug the extra vucumn hose that plugged that used to plug up to the TB to the 300zx TB. I don't know if that's right. It may be the TPS. How do you check the 300zxt TPS? Anybody with experience with this setup?
 

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Hiya Yo - I admit I don't have any experience with the throttle body, but you may yet have a vacuum leak that is causing you to run lean. One area of concern I had with the spacer is the slight gap in the intake manifold where the cold start valve is ( the place that is not round, covered by the stock Z manifold gasket. I had planned to fill in that area with an aluminum weld or epoxy, then smooth it out so the gasket has a better sealing surface. Just a thought, since I sold you the spacer.
 

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Hey, I had a vacumn leak from vacumn advance hose at the T connector. I competely bypassed the TB vacumn hookup. Now, I have no T connector. It not lean much anymore. Now the intake air velocity is slow in low rpm I think. I'm going to try bumping the timing a little, or may be changing the springs in the distributor so it'll release the timing quicker. I ported the intake but I left the hump on top. I don't think that's going to cahnge too muce air flow. I also bore the mouth of TB to 70mm to 55mm taper for faster air flow. I can feel the difference. I just need to fiddle with. Oh, I got the TB yesterday.
 
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