Anybody have a Header?

[cobraz240z]

Hey im looking for a header for my 240z I have a round exhoust port head need one a.s.a.p. and would a square port 1 work?

[JaysZ]

damn.. i have 2 extra square port ones.. and the answer is no they wont work lol

[zeiss150]

I think the square port works on the round it just doesn't flow as well because its not matched. MSA sells them for about $150 I think smog or no smoge whatever you need.

found this on ebay

http://cgi.ebay.com/ebaymotors/Datsun-240z-260z-280z-Z-240-260-280-headers-square-port_W0QQcmdZViewItemQQcategoryZ33631QQitemZ8068227421QQrdZ1QQsspagenameZWDVW

Im sure someone will correct me if you can't use the square with the round, but I know the bolt pattern is the same.

[katman]

Hey, but the good news is a square port will work as good on a round port head as 99% of the round port headers work on a round port head. Which is to say they look just as cool, which is good for a 15% power increase easy.

[JMortensen]

Keith, I've seen your dyno results on zhome.com. Always wanted to ask you: Is it that the headers don't flow better, or is it that the ITS engine can't utilize the increased flow?

 

The engines that I've put headers on certainly seemed to respond, but they were triple carbed or at least cammed 2.8's with 2.5" all the way back.

[katman]

The zhome results were just a piece of the initial results we collected over a 3 year period. The real work was done on an engine dyno and not shown. Out of morbid curiosity I also made note of other header testing done by car mags over the last few years from the import tuners to the big block Chebbies. For the ITS motor it's easy to blame the lack of response on the stock cam and carburetion, although when we quit the ITS 240Z program we were making 208 real SAE east coast hp, which is proly more than most people get with triples and a cam that don't have the resources to really tune. Still, about 4-6hp could blanket the results between most aftermarket headers and a good N42 manifold on a 200 hp Z motor utilizing the tuning tools most people would have available. At best you might get 4% or 8 hp. The real eye opener for me was a test I ran across in Super Chevy or something like that where they had a 454 with your typical mods: aftermarket cam, aluminum aftermarket heads, decent compression, proper Holley, Edelbrock manifold, etc. The difference between the stock 454 exhaust manifold and the best header they tested was about 20 horsepower, or 4% of the 500 the motor was putting out. Basically, and amazingly, about the same as a Z.

So I'll give you 4-6% for headers over a stock manifold IF you can tune to it (which means lambda sensors and dyno runs), and 1-3% difference between any header and any other header. That would be for an engine in the mild category. Wouldn't be fair to test an N42 manifold against headers on a 3.1 liter with trips and a cam since the N42 wasn't designed for that much flow. But if Nissan had put out 3.1 liter motors with hot cams and triple Mikuni's, I bet the difference between the stock manifold for that and all the aftermarket headers would only be 4%. Hey, I put them on our street Z's because they look and sound cool, but I don't kid myself about how much horsepower I'm making with them. Definitely a requirement for bigger and hotter motors since there is no stock manifold equivalent. Am I making sense?

[JMortensen]

Yeah, I've always kind of taken issue with your numbers, but I'm a triples and big cam guy, so I don't think your comments were aimed squarely at guys like me. I do agree with the idea that it isn't worth a whole lot on a SU'd stock cammed L engine, and I do think the cheaper headers might be worth quite a bit less than a really good one.