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Biggest restriction for TBI engine is the HEADS.. you can put all the exhaust in the world on it, they heads will still not flow.
I've done headers and exhaust on LO5's...It doesn't help.if you can't get more air in, you don't have to worry about getting it out.
Quote from: Jim Rockford on January 16, 2010, 08:04:21 AMBiggest restriction for TBI engine is the HEADS.. you can put all the exhaust in the world on it, they heads will still not flow....but at least everything downstream of the heads will.It's understood that TBI heads' flow numbers suck. But a full exhaust can net 25 hp or so without touching the heads. And if you do decide to replace the heads with higher performing units, it becomes even more crucial to relieve restriction downstream at the same time. So, cutting exhaust system losses at an early stage in a performance build makes good sense.He didn't specify how much power he was looking for, but he did say he was looking for some "fairly simple upgrades." I don't think head swap or extensive head porting falls into that category.
Quote from: eventhorizon66 on January 16, 2010, 11:53:53 AMQuote from: Jim Rockford on January 16, 2010, 08:04:21 AMBiggest restriction for TBI engine is the HEADS.. you can put all the exhaust in the world on it, they heads will still not flow....but at least everything downstream of the heads will.It's understood that TBI heads' flow numbers suck. But a full exhaust can net 25 hp or so without touching the heads. And if you do decide to replace the heads with higher performing units, it becomes even more crucial to relieve restriction downstream at the same time. So, cutting exhaust system losses at an early stage in a performance build makes good sense.He didn't specify how much power he was looking for, but he did say he was looking for some "fairly simple upgrades." I don't think head swap or extensive head porting falls into that category.I couldn't have said it any better.
Quote from: jimbo on January 25, 2010, 11:05:09 AMQuote from: eventhorizon66 on January 16, 2010, 11:53:53 AMQuote from: Jim Rockford on January 16, 2010, 08:04:21 AMBiggest restriction for TBI engine is the HEADS.. you can put all the exhaust in the world on it, they heads will still not flow....but at least everything downstream of the heads will.It's understood that TBI heads' flow numbers suck. But a full exhaust can net 25 hp or so without touching the heads. And if you do decide to replace the heads with higher performing units, it becomes even more crucial to relieve restriction downstream at the same time. So, cutting exhaust system losses at an early stage in a performance build makes good sense.He didn't specify how much power he was looking for, but he did say he was looking for some "fairly simple upgrades." I don't think head swap or extensive head porting falls into that category.I couldn't have said it any better.Well all I can say is enjoy flushing your money down the toilet. I've only been hopping up carsand engines for 20years.. Sorry if my experience doesn't hold enough water for you.