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Discussion Starter · #1 ·
I'm thinking about putting headers on my '72 240. Will they really be beneficial without any other modifications to the engine? I'm trying to decide if they are worth the expense or should I go back with the original exhaust manifold. I don't want to go into the engine with any other mods right now. Anybody have an opinion?
 

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> I'm thinking about putting headers on my '72
> 240. Will they really be beneficial without
> any other modifications to the engine? I'm
> trying to decide if they are worth the
> expense or should I go back with the
> original exhaust manifold. I don't want to
> go into the engine with any other mods right
> now. Anybody have an opinion?

I was reading a post on the IZCC list a while back about someone doing a flywheel dyno on a stock L24 and the header did nothing. BUT, the engine was stock. If you plan on a custom exhaust with it, it may help some. The big help you get wtih a header is when you need the extra flow when using a cam, triple carbs, better air filters, things like that. If you are planning future mods and NEED a manifold OR header of some sort, go with the header to save yourself from getting two when you need one. Anyway, that's enough babaling, sorry.
 

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Gain 3 sec 0-100 for $80

Forget the header on a stock 240 engine.I put one on my stock '72 240 engine in 91 and it made very lttle difference if any in acceleration.HOWEVER,the single most important thing i did was change to dual K&N air filter setup.this mod picked up my stock 240 3 seconds 0-100 over a stock clean air filter.I tested it 5 times with filter and 5 times without on an abandoned stretch of road each time the car ran about 2.8-3.2 seconds faster with the k&n air filters.Also I would put a bigger exhaust system on as the stock exhaust pipe is way to restrictive.However a header will be of virtually no benefit on a stock engine. Later ,norm
 

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Discussion Starter · #4 ·
Re: Gain 3 sec 0-100 for $80

> Forget the header on a stock 240 engine.I
> put one on my stock '72 240 engine in 91 and
> it made very lttle difference if any in
> acceleration.HOWEVER,the single most
> important thing i did was change to dual K&N
> air filter setup.this mod picked up my stock
> 240 3 seconds 0-100 over a stock clean air
> filter.I tested it 5 times with filter and 5
> times without on an abandoned stretch of
> road each time the car ran about 2.8-3.2
> seconds faster with the k&n air filters.Also
> I would put a bigger exhaust system on as
> the stock exhaust pipe is way to
> restrictive.However a header will be of
> virtually no benefit on a stock engine.
> Later ,norm
Just about any modification you do to a production engine is going to be a trade off of good and bad effect. Headers are a good example. With headers in theory you will flow exhaust faster and thereby gain hp. In fact not much. Keith Thomas of Lockheed Martin during the day and Reckert Racing on the weekends did indeed chassis dyno several exhaust systems and found headers to be of no benefit on a relatively stock motor. Most of us who street drive our Z cars are close to stock no matter what we think or imagine. With headers you increase underhood temperatures which stresses the rubber parts and generally makes the car run worse. Headers except good ones and in my opinion there is only one good one (Nissan Motorsports) tend to leak. Warm up takes longer. They are loud. They rust out quickly unless you take certain expensive measures to prevent it (Ceramic coating such as Jet-Hot). On the plus side they sound cool.
I would have a 2.5 system bent and welded together ending in a good low restriction muffler like a Borla. This will match the header in HP figures on the dyno, be quieter and have few of the bad manners I described above. Also, Norm is way right. The K&N really honks.
 

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One single mod by itself isn't going to make a huge difference. These guys that are saying the K&N makes a difference are right, it does. But I would bet that they already have a header and performance exhaust prior to the K&N filter mod. If you put a set of K&N's on a completely stock 240Z you wouldn't notice much performance gain. But then later when you get a header (hopefully a well designed one) and a performance exhaust the power gains will really show. If you can get air into the motor, but not out your not much better then before when the air had trouble getting in and out, and vice versa. If money a problem (like in mine and a lot of other people's cases) save up and buy one piece at a time. Don't go out and buy the cheapest so called performance parts you can find they're not always the best (unless you find some high quality good used items). I've tried the Motorsports Auto 3 into 2 header and its not a good one. It was only slightly better than stock, and that was with a 2 1/2 exhaust. Later I went and purchased the Nissan Motorsports race header and the difference in performance was day and night. As for a airfilter I went with a ITG unit as I thought it was better then the K&N (not to mention more $), as the ITG can flow from the top as well as the sides. I've added a electric fuel, gross jets, and changed needle jets over the years. Right now I'm in the process of turning my L24 into a full race spec motor. It's been over 2years and a lot of $, and I'm still not done. But hopefully by mid summer I'll have the fastest L6 powered 240Z in ND. There are a couple 240Z' and 280Z's with v8's but I should be quicker and faster than them.
> I'm thinking about putting headers on my '72
> 240. Will they really be beneficial without
> any other modifications to the engine? I'm
> trying to decide if they are worth the
> expense or should I go back with the
> original exhaust manifold. I don't want to
> go into the engine with any other mods right
> now. Anybody have an opinion?
 

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SPEAK FROM EXPERIENCE NOT OPINION!!!!!

If you aint done it and tested it JEFF how about not speaking about something you don't know about.When I tested the K&N on my car at the time I had everything stock except for a cheap turbo muffler. The stock 240 air cleaner assembly is EXTREMELY restrictive. Later,norm
 

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Re: SPEAK FROM EXPERIENCE NOT OPINION!!!!!

> If you aint done it and tested it JEFF how
> about not speaking about something you don't
> know about.When I tested the K&N on my car
> at the time I had everything stock except
> for a cheap turbo muffler. The stock 240 air
> cleaner assembly is EXTREMELY restrictive.
> Later,norm

How is he speaking from opinion when he said he's tried all the stuff he has? I put the K&N separates on my 72, and I didn't notice much difference at all (this was *after* I put in a 2 1/4 Exhaust which did make a big difference even with a stock manifold) Also on my old exhaust, the pipe broke where it attached to the front of the muffler, and I swear that thing necked down to the diameter of a quarter at that point. Now how's that for restrictive? After opening it up with the big exhaust, I must admit I did lose some low end torque, but the high end breathing more than made up for it. and based on the feel I would estimate at least a 10 to 15 HP gain plus almost a second off the 0-60 time. After installing the K&N's on top of this I can't say it made a ny noticeable difference. I still would use the K&N's because they are a much better filter than stock and will significantly reduce engine wear caused by the intake of dusty air.
 

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Zebra

He tried the ITG not the K&N and he did not test in a scientific matter as I did. These tests were all done within an hour and they were timed with a stopwatch not SEAT of the Pants.The implication was that i as lying and I did not appreciate it.All I can say is that it did improve my cars 0-100 time by 3 secs, if it did not help yours, then maybe you did not run the same ignition and cam timing and maybe you shifted earlier than i did. Later ,norm
 

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Re: Zebra

> He tried the ITG not the K&N and he did not
> test in a scientific matter as I did. These
> tests were all done within an hour and they
> were timed with a stopwatch not SEAT of the
> Pants.The implication was that i as lying
> and I did not appreciate it.All I can say is
> that it did improve my cars 0-100 time by 3
> secs, if it did not help yours, then maybe
> you did not run the same ignition and cam
> timing and maybe you shifted earlier than i
> did. Later ,norm

I wasn't implying that you were lying, I just thought you misread his post (though looking back it appears I did. I got the impression that he ran the ITGs and then switched to K&N's but apparently not.) Still I think you're maybe getting a little too excited about the whole matter, there's no need to get into an argument about air filter preferences and impressions or results from installing said air filters.
 

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Re: headers - not!

Stephen,
I had a long talk with the owner of Rising Sun Performance in Ft. Worth, TX. on this subject in refernece to my '77 280Z. He has 20 years experience with Z cars, ex Nissan parts guy, certified mechanic, builds & sponsors racing Z's, etc. Here is his take on it. A good set of free flowing headers are good for 3-5 HP and that is generally noticable above 5,000 rpm. The problem is, who would ever notice 3-5 hp and how often do we drive above 5,000 rpm? They are also a maintenance problem because of their tendency to warp and burn through, both of which end up as nasty exhaust leaks. His recommendation for a car that is mostly stock is to get a K&N filter and invest in a good 2.5 exhaust & muffler. Keep the stock exhaust manifold - it actually is a good design and, if you have it cleaned up internally removing casting flashing, etc., it is nearly as good as the less reliable header. That is exactly what i intend to do.
for the fuel injected guys, he also didn't recommend going to an oversize AFM unless the engine was going to be turbo or supercharged. Again - not enough bang for the buck.
Folks that plan on all-out racing - now it's another story - you'll need every HP you can get - and you'll pay dearly for it.
Phantom
 

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Discussion Starter · #13 ·
Re: SPEAK FROM EXPERIENCE NOT OPINION!!!!!

> If you aint done it and tested it JEFF how
> about not speaking about something you don't
> know about.When I tested the K&N on my car
> at the time I had everything stock except
> for a cheap turbo muffler. The stock 240 air
> cleaner assembly is EXTREMELY restrictive.
> Later,norm

It's always easy to dig a 20 year old race vet out of the closet but that doesn't say much really, if you want to get more go do some reasearch, you'll find while the HP gain in min. the HP curve the engine produces is sharper than without header or with non-tuned headers like you get a Motorsport which are crap. A good tuned set made for a certain motor (Nissan Motorsports) will make a difference in the RPM range of the cam and carb setup no matter what cam or carbs but it will enhance any additions made to them. The mistakes most are when the wrong size primary header pipe and exaust pipe are used with a set cam/carb setup and it's the no-brainer that doesn't get any performance out of a proper set of headers. Don't start out going cheap on headers and then say they arn't worth it, get a set that is engineered for the car as they take tube size and lenght into account so it has the proper resonance that helps with scavaging effect. This is one reason Nissan makes 2 sets of headers with different primary sizes, they know what they were doing. Heat isn't a problem if you use either coating, header blankets or wrap or even a good heat shield, that much is common sence. The stock manifold is well setup for the stock car but it can be improved upon as if it was done as well as it could have been the car would have added cost that the MFG. wouldn't think worth it in lost sales of the higher car cost. But stock is better than Motorsports junk.
 

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Re: SPEAK FROM EXPERIENCE NOT OPINION!!!!!

I have a pacesetter, bought it when I had just got the car and it cost about the same as a used manifold here, so I bought it. With the K&N it works fine for the stock engine. A little more power, a lot more noise from up front. I do not mind the noise, usually the rock is up anyways. I took all the heat sheilds off except the one that covers the brakes and clutch, that curved verticle one. The rest on the intake manifold are off, and even when it is 105 here in the summer, I have ZERO problems, for the past three years. No wrap, no blanket, no coating, nothing! I do not know about others, but I like even the cheap ones when you have to replace the manifold anyways. Also, no leaks and I have reused the gasket a couple times when working on the engine, and now am using a stock gasket with copper coat on it, no leaks. No warps either. It has been very good as far as that is concerned. If you do not mind the noise, buy one if you have to replace the stock one anyways. As a note though, I will buy a Motorsport one next time and have it coated, that is for my very modified engine though.
Joshua L.
 
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