Which direction to go with custom exhaust (89' F150 4x4 351W)
#16
I guess youre posting up a picture of your "700 hp mustang with shorty headers" to justify your belief that long tubes provide marginal gains over shorties...
sorry, but that doesn't prove anything, except that you have a lot to learn. big difference between the engine in your pic, with a supercharger dangling off the front, and a naturally aspirated engine. you could pick up a lot of hp with a good set of long tubes on that engine, by the way.
sorry, but that doesn't prove anything, except that you have a lot to learn. big difference between the engine in your pic, with a supercharger dangling off the front, and a naturally aspirated engine. you could pick up a lot of hp with a good set of long tubes on that engine, by the way.
#17
Had them. Working on the starter or pulling the engine tune ups... more of a pain than it was worth. There was a 2 hp loss from my shortys under 5000 rpm. The 7 lb ft of tq I lost was not even noticed either. I will give you this over 5000 I did lose more. But how often will you be running a truck up to 7200 to see the full benefits of the long tubes.
#19
#20
I still think that shorty or mid length headers are just fine for a stock or near stock motor. It really seems to me that long tubes would be most beneficial at really high RPMs which most street vehicles and trucks never really see. I just don't see the point. I have mid length headers on the Mustang and its power is great.
#21
youre comparing your engine with substantial supercharge boost to an NA application...the same rules do not apply. the more boost that is run on a forced inducted engine, the less effective the exhaust "scavenge" from long tubes is. this is also directly correlated, and vastly effected, with/by the cam, any overlap forces exhaust to be driven out of the cylinder under boost. scavenge effect of long tubes is negated by boost, which is why long tubes make considerable power over anything else on a naturally aspirated setup.
you can gain power with long tubes on an engine that sees low boost, that can still benefit from scavenge, or high boost that can benefit from large primaries akin to "racing" style headers (long tubes or shorties).
any marginal gains you saw from long tubes could stem from a lot of variables. regardless of those variables (primary tube size, boost, cam profile, etc) your results cannot be applied to a naturally aspirated engine, where the rules and physics behind making power are entirely different than forced induction.
huge gains can be had with long tubes on a naturally aspirated engine, but it is torque production off idle, resulting in hp across the board, not high rpm hp. now, dont find a 8000 rpm revver that has giant primary tubes to match that rpm target and say "long tubes are only for high rpm", because the primary size on said 8k rpm revver is going to be large enough to be adequate at those rpm. if there was such a thing as "variable size tube headers", the tubes would shrink small on take off and low rpm, and grow larger according to rpm. those dont exist, so primary tube size is a tradeoff just like cam/head selection. you pick the tube size that suits your goals and works best with your combo.
if you bolt up long tubes to a stock small block ford, even a 302, you will notice it at the pedal. maybe not so much with an automagic slushbox, but head/cam/long tube packages go together for a reason in order to make max power in an NA application. the more radical the head/cam combo, the greater the gains of long tubes will be a result.
its not uncommon to unlock 40/50 hp with 50/60 lb/ft of torque from long tubes on an engine that actually makes decent power. lsx's are a perfect example, they come with shorties, already have decent heads and cam, and gains of 25-35 hp with 35-50 lb/ft have been seen for almost two decades now. add a cam, and the gains from long tubes are even higher. add heads, cam, long tubes... look out. the exact same thing can be said about sbf's, the 351w in particular, where a properly matched head/cam/long tube combo will yield huge gains and make a hellofa runner.
#22
#24
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It's been said here on many occasions.. the results you get with these motors in a lightweight car simply don't translate to a truck that is on average 1500lbs heavier.
#25
If its a built motor I might change my mind. On a stock motor I just don't see how it can make much difference. My buddy had an 85 F150 with a 5.8 HO. We put long tubes on it and saw very little difference.
I know that cars and trucks are apples and oranges. I've driven cars with similar setups and with both kinds of headers and didn't see much difference if any.
I never argued the fact that long tubes are better. I am just saying that they are not always needed or worth it. I didn't miss any memo. I think you missed my point.
I know that cars and trucks are apples and oranges. I've driven cars with similar setups and with both kinds of headers and didn't see much difference if any.
I never argued the fact that long tubes are better. I am just saying that they are not always needed or worth it. I didn't miss any memo. I think you missed my point.
#26
Nothing is going to make that much difference on a stock 80s ~200 hp engine until you address the things that prevent power from being produced. It's the miserable example of heads and cam that are the problem. Until that is addressed, nothing will net big gains...but how long tubes change the part throttle feel is key. Like I said, an automagic slush box might not transmit the pedal feel of direct drive, but i assure you every time I've bolted a pair of long tubes onto anything whether it's been super slow or fast already, I've noticed it.
If long tubes aren't noticeable, then shortys certainly will feel as though you've done nothing at all.
If long tubes aren't noticeable, then shortys certainly will feel as though you've done nothing at all.
#27
So I didn't even know this thread was a discussion of long vs short tube headers b/c I started one of my own. My situation is that I could put on some "cheap" shorties and pretty much not have to change anything about my exhaust system. If I ran long tubes though, I'd have to have a shop re-route around the transfer case from what I understand. Also, right now my exhaust is a Y pipe that is 2.5" duel in, and 3" out. That goes down to 2.5" back for I don't know 18-24" then to a Thrush 25" glass pack where the old muffler was. The Thrust pack is 2.25 in and out then just stock (behind the wheel and out behind the tire which is I believe 2.25" as well). Do you all think that piping is big enough for long tubes? I wouldn't want to have the whole exhaust re-done b/c it's too small.
#28