Installing JBA Shorty Headers

Discussion in 'SN95 4.6L Mustang Tech' started by BlackenedSVT, May 16, 2005.


  1. BlackenedSVT

    BlackenedSVT Active Member

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    Auto zone huh...hmmm. There is one a bit aways from me, but i'll hike over there and see if they have one tomorrow.
    #81
  2. MT1083

    MT1083 New Member

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    You might wanna call them first and make sure that they have it since its a decent drive for you. :nice:
    #82
  3. stangman

    stangman Well-Known Member

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    i saw them at sears the other day too
    #83
  4. BlackenedSVT

    BlackenedSVT Active Member

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    Ok so i did PART of my header install today. I got just the driver-side header on. I have a few problems though:

    1. My JBA headers did not come with gaskets 2nd-hand, and it would appear they dont need gaskets...? :shrug: They are not flat like the stock manifolds. There seems to be a circular outline of weld and Silicone Sealant around the opening where the manifold meets the engine. and it seems to act as a gasket. My question is should I still re-use my stock gaskets, because with that bulge on the JBA headers already, the stock gaskets dont seem to fit too well...

    2nd problem:
    My JBA headers did not come with manifold studs to go to the H pipe. So I have to re-use the stock header studs to connect to the H-pipe. HOWEVER, they screwed into the stock manifolds, and they DO NOT screw into the JBA headers, rather they just slide in. So I am having problems tightening the JBA headers to the H-pipe. It is tight, but seems like it could come loose later on. Any hints? :shrug:



    Also, with both JBA headers installed tomororw, can I run the car to see if there are any exhaust leaks before i reinstall the struts, shocks, etc...?
    #84
  5. stangman

    stangman Well-Known Member

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    1 - yes, reuse the stock gasket. i did with no problems at all

    2 - tighten it down like that as best ya can

    3 - yes. start it up & check for leaks before you put the k-member & struts & all back up :nice:
    #85
  6. BlackenedSVT

    BlackenedSVT Active Member

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    Ok, im headin back into the shop now @ 7:30am to get this header install done hopefully today. I'm doing this all by myself.
    #86
  7. stangman

    stangman Well-Known Member

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    good luck man :nice:
    #87
  8. BlackenedSVT

    BlackenedSVT Active Member

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    ok the headers are in!! After a REDICULOUS amount of hours put in, in 2 days. I got them installed. I was all alone, and is not a project I would advise to do alone!

    Fortunately my Uncle showed up for an hour here or there which helped a ton.

    Well the car is back together and it runs good. Doesn't sound any different, but I think it feels a tiny...TINY bit better. The car should be able to breathe better now with my new FULL exhaust =)
    #88
  9. stangman

    stangman Well-Known Member

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    congrats man :cheers: good job, told ya you could do it :nice:
    #89
  10. BlackenedSVT

    BlackenedSVT Active Member

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    And for help to any others who might be searching for this JBA install...

    I'd like to add that I DIDNT use a 13mm "S" wrench. Just a standard small/stubby 13mm wrench and a LOT of patience worked just fine :nice:

    And thanks Stangman =)
    #90
  11. stangman

    stangman Well-Known Member

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    glad i could help :)
    #91
  12. stangman

    stangman Well-Known Member

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    btw - did you drop the k-member? i think you did but i couldn't tell by your posts whether or not you did :shrug: just curious
    #92
  13. 300bhp/ton

    300bhp/ton New Member

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    Well as you have know installed them (with apparently a lot of hassel) this may be academic.

    But 15BHP let alone RWHP is probably very optimistic, however I would be intreaged to know what they do produce if anything. Are you going to get it dyno'd?

    As for your 1st edit - they where free. Well I still don't think they where worth it. I would have sold them and put the money towards either LT's, electric water pump or a long term saving plan for a blower as they will all offer much better and worthwhile gains.

    As for your 2nd edit. Well when any manufacture or retailer is quoting such things you need to take it with a pinch of salt.This applies to anyone who is wanting you to part with your hard earned MONEY.

    Becasue you have no idea how the car was setup or tested. And the claim is a combined claim with other components and possible a tune, and or different test condidtions. And you don't even know what car it was tested on, it may have been 700bhp blower drag engine, which they slapped a stock exhaust on and then theirs own - well of course it produce more (I'm NOT saying this is what they did, I am mearly trying to highligh that it is a meaningless statistic without an explanation of how it was acheived and what it is directly being compred to.)
    #93
  14. BlackenedSVT

    BlackenedSVT Active Member

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    Yes I dropped the K-member. While it was very hard to do by myself, I couldn't imagine NOT dropping the K-member...there is no room to work!

    I will post a few pics later on today hopefully.
    #94
  15. BlackenedSVT

    BlackenedSVT Active Member

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    Ok well 1st off, my friend was selling these headers for $350...they are used and dont come with gaskets and originally cost about $700. But he gave them to me for free instead of selling them. But If i were to turn around and sell them for $350, it really wouldn't do jack in terms of putting money toward LT headers (as they are like $800+). I will also save LT headers for when I get my cobra :D Shorties are fine for my GT now. And since they were free, even the labor i think it was worth the gain. I dont care about the hp increase, if i DID, then I would have saved for the LT. But considering the situation I dont care if they were even 1rwhp, its a gain, it was free, and I had fun learning and workin on my car :nice:

    EDIT: Oh and I forgot to add that I will NOT be taking it to a dyno any time soon. I currently have no more money and would like to buy 3.73 gears and a tuner before I go to get it dynoed. Not to mention I wouldn't know what the gains were on the headers since i didn't dyno the car before the install...or at all for that matter. I WILL be able to let you know how much gain I got out of my completed full exhuast though.
    #95
  16. Evenflow

    Evenflow yellow snow cone lover

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    Very cool, and congrats :nice:

    how much power do LT headers usually add on the 99+ GTs?
    #96
  17. NasaGT

    NasaGT Founding Member

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    congrats on the install! :cheers:
    #97
  18. 300bhp/ton

    300bhp/ton New Member

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    I think it all depends. Potentially a fair bit.

    If you are running a fairly stock engine then the gains will be minimal. Assuming you have already done the rest of the exhaust the LT's are probably worht around 10rwhp. So % wise is not bad on a 230rwhp car.

    People like KB don't recommend them as you are still only likely to see 10rwhp gain on a 9psi 1.7 blower. So it would be 10rwhp extra on a 400rwhp car. Probably no real benefit just a stack of cash and hassel.

    If you compare a completly stock exhaust to a full exhaust (no cats, LTs, mid pipe, straight thru silencers and bore incrase) with a tune it should be knocking on the door of 30-40rwhp.

    You won't need a tune but it will get the most out of it. If you're going for monster n/a engine, with ported heads, high lift cams, bigger TB and an agressive tune then LT's are a must else the engine will be strangling itself.

    But it all depends on your application, as increasing the manifold size with LT's will also push the peak power further up the rpms. So if you are wanting to create a torque monster style motor with loads of low end grunt the stock manifolds will work very well.

    Personally, I don't think the 4.6 engine is worth looking at as a n/a motor, it just doesn't produce the power and is expensive per bhp gained compaired to a supercharger.

    If it was me all I would do is add an H or X pipe with high flow cats (keeps it legal and less messing about) with a nice performance exhuast. Then slap on a blower (any of the 3 - twin screw/centrifugal/roots). For me the 9psi Kenne Bell is the best option with their CAI kit and big MAF. All this should net you around the 400rwhp mark on regular 91PON octane fuel.

    Other mods should include gears (3.73 or there abouts) and suspension and brake mods.

    Future power imporvements can be sort via some agressive cams (should still be ok on 91 octane fuel) or increase the boost but this is more likely to blow the engine.

    All this my seem expensive, but in the long run it will probably be very similar money to an n/a setup and still produce alot more power and be much more streetable.
    #98
  19. BlackenedSVT

    BlackenedSVT Active Member

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    Yes the blower route is VERY expensive. I personally LOVE N/A engines, and to have 350hp (not that I have that, im just saying) and beat a supercharged car with my NA car :D However you are right, the 4.6L SOHC engine isn't anything of a monster motor NA. A cobra would be a better engine to mod for NA applications and thats not even that spectacular. The 5.4L Cobra R (and soon to be GT500 engine :drool: ) is the motor you want to for NA applications.

    I think I'll be keeping this car NA and get a blower on my Cobra when I buy one in a few years. I scraping together every penny under the couch for the new Shelby :hail2:
    #99
  20. 300bhp/ton

    300bhp/ton New Member

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    that'd be cool :nice:


    Although 350bhp maybe possible n/a a roots blower on an otherwise stock motor will easily make 350rwhp, so at least 380bhp.

    Some engines make great n/a units, but there is two aspects to it.

    1. specific output per litre
    2. engine capacity

    Often larger capacity engines will produce less bhp/litre.

    Personally I doubt whther the SOHC 4.6 V8 will produce more than 75bhp/litre and still be street able. More s possible but it will have horrible road mannors and even worse fuel consumption.

    so 75bhp x 4.6 = 345bhp, which on a manual GT would be in the region of 300-310rwhp. The 3v per cylinder and the DOHC unit may fair a little better but only by a few bhp/litre more.

    The DOHC unit will probably produce around the 100bhp litre mark for race use (this would be circuit racing not drag racing).

    So the modular engine has 2 enemies really. Although 75bhp/litre is possible you are starting with a measly 56bhp/litre (260bhp), so bolt-ons will only buy you in the region of 10hp/litre more (303bhp or around 260-70rwhp mark).

    Also the fact that you only have 4.6 litres to play with doesn't help much.

    By contrast a TVR 4.0 Stright 6 engine will produce 400bhp stock, ultimatley it doesn't have the capacity either, but as far n/a goes it still poduces more power than a very highly tuned 4.6, weighs a lots less and is less than 2/3 the size.

    The other end of the scale is the like of the LS1. In stock trim it has 345bhp which is only marginly better than the 4.6 with 60bhp/litre but because it has more capacity it will always be out infront bhp wise. Also the Ls1 does seem to respond fairly well to mods and in after market tune produce goos specific outputs such as 80bhp/litre (456bhp or around the 410rwhp mark) bolt ons and a cam will see this power level.

    So it is fortunate that the 4.6 responds fairly well to FI. In stock trim it should be fairly easy to get 100bhp/litre out of it (460bhp about 420rwhp).

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