1 5/8 vs. 13/4 primaries headers

[TRMI8TR]

Found this old thread and thought I would share it. I am not the OP nor the one doing this test. Just reporting an old thread.


http://www.svtperformance.com/forums/new-edge-cobras-51/862324-1-5-8-vs-1-3-4-headers.html

 

[evolve]

Great find really. Goes to show that size doesn't matter. At least that's what she told me...

 

[TRMI8TR]

Great find really. Goes to show that size doesn't matter. At least that's what she told me...

^^^lol she was trying to make u feel better about your smaller primary. I'm sorry.

 

[evolve]

lol

 

[cgarray17]

Nice to know thanks for the find!

 

[shurur]

I posted that and got no responses.
Why?

Because some gurus have sworn up and down that 1-7/8" is better.

Now for the rebuttals with disclaimers...

 

[SVT_Troy]

thats interesting....

 

[TRQJUNKIE]

Very good article... ill be buying those 1 5/8 pacesetters I believe.

 

[Roots-type]

Alot of people overlook how well boost cleans out the cylinders. It also goes unmentioned in general open forum that a smaller primary will move gases at a higher velocity than a larger primary will. Of course there's a point where an engine will need a larger primary, but in our case the 1 5/8 work very well and I will chose the faster air over slower/sloppy air any day of the week and twice on Sunday.

 

[SlowSVT]

Alot of people overlook how well boost cleans out the cylinders. It also goes unmentioned in general open forum that a smaller primary will move gases at a higher velocity than a larger primary will. Of course there's a point where an engine will need a larger primary, but in our case the 1 5/8 work very well and I will chose the faster air over slower/sloppy air any day of the week and twice on Sunday.

The same might be said of running a 2 1/2" system over a 3" system (except turbo's). Engines run like poo if they are overexhausted even open header cars. On an N/A engine it will show up as a slight stumble or hesitation but a supercharger will mask that.

 

[evolve]

Very good article... ill be buying those 1 5/8 pacesetters I believe.

Great choice! Stainless works and ARH both have X pipes that fit as well as Pacesetters own o/r X.

 

[TRMI8TR]

Great choice! Stainless works and ARH both have X pipes that fit as well as Pacesetters own o/r X.

I've been saving for some time now for some ARH headers, I'm definitely going with 1 5/8 and 2 1/2 collectors. Plus they're slightly cheaper to the wallet. Need like $300 more almost there:banana:

 

[SVT_Troy]

I've been saving for some time now for some ARH headers, I'm definitely going with 1 5/8 and 2 1/2 collectors. Plus they're slightly cheaper to the wallet. Need like $300 more almost there:banana:

I think ARH only makes the 1 3/4" & 1 7/8" primaries. Correct me if I'm wrong though. I was considering going with the 1 3/4".


Who has done testing to show when is too much on the S/C'd 4v's?

 

[TRMI8TR]

I think ARH only makes the 1 3/4" & 1 7/8" primaries. Correct me if I'm wrong though. I was considering going with the 1 3/4".


Who has done testing to show when is too much on the S/C'd 4v's?

ARH does have 1 5/8 with 2 1/2 collectors.

99-04 Mustang GT & Cobra

 

[TRQJUNKIE]

Great choice! Stainless works and ARH both have X pipes that fit as well as Pacesetters own o/r X.

I was actually thinking of doing a custom 3" prochamber to hook up to the 3" collectors. Then have it bottle neck down to the 2.5" catback with magnapack mufflers. Might be a lot of work though but should sound decent

 

[tarheeltrooper]

once up to a certain power level and depending on the forced induction you have is when the 5/8 vs the 7/8's come into play. your average twinscrew 600 hp car is fine with 5/8 but when you get up in the 800 range with turbo and centri you need bigger. if not you will create the term choking aka starving the motor. this is what is happening to me at the moment. 1 5/8s and 2.5 is killin my centri built motor setup. many threads on certain mustang forums via google search has proved to gain 20-40 ish hp when making the big exhaust switch, again depending the setup.

 

[SVT_Troy]

once up to a certain power level and depending on the forced induction you have is when the 5/8 vs the 7/8's come into play. your average twinscrew 600 hp car is fine with 5/8 but when you get up in the 800 range with turbo and centri you need bigger. if not you will create the term choking aka starving the motor. this is what is happening to me at the moment. 1 5/8s and 2.5 is killin my centri built motor setup. many threads on certain mustang forums via google search has proved to gain 20-40 ish hp when making the big exhaust switch, again depending the setup.

I'm glad you said this. I'm currently running mac long tubes but since my motor is out I'm trying to determine if I should go to a bigger header. I want to get a new header no matter what. I'm either wanting to get new pacesetter 1 5/8'' which would be the same as my macs or to go with ARH 1 7/8".

My reasoning is that I may go E85 which will have my running higher boost and i want to know if I would benifit from going to a bigger header

 

[tarheeltrooper]

I'm glad you said this. I'm currently running mac long tubes but since my motor is out I'm trying to determine if I should go to a bigger header. I want to get a new header no matter what. I'm either wanting to get new pacesetter 1 5/8'' which would be the same as my macs or to go with ARH 1 7/8".

My reasoning is that I may go E85 which will have my running higher boost and i want to know if I would benifit from going to a bigger header

I sure wish I would have while all mine was out but now I am slowly upgrading everything with it on the car. This was explained to me by Bob Kurgan, the king of E85 and tuning mod motors (in my opinion). I am going with kooks 1 7/8's with 3 inch collectors, into a 3 inch hooker mid into the new bassani catback I just installed. After doing research I was amazed at the gains when the entire exhaust not just the headers were all upgraded! Its just so dang expensive, grrr.

 

[shurur]

I sure wish I would have while all mine was out but now I am slowly upgrading everything with it on the car. This was explained to me by Bob Kurgan, the king of E85 and tuning mod motors (in my opinion). I am going with kooks 1 7/8's with 3 inch collectors, into a 3 inch hooker mid into the new bassani catback I just installed. After doing research I was amazed at the gains when the entire exhaust not just the headers were all upgraded! Its just so dang expensive, grrr.

The general consensus in this forum was ~700+ HP. So that makes sense.

I'm still not sure that this dyno result wouldn't hold true for the NA 99-01 cobras as well.
I suspect that 1-5/8" is best for a 5.3L NA BB stroker making 450+ HP (500 possible!) and certainly fine for a 5L stroker making 400 HP.

It's when folks start talking about bigger is better right from the get-go that bothers me a bit, people spending $ on headers that are hurting them.

 

[tarheeltrooper]

The general consensus in this forum was ~700+ HP. So that makes sense.

never seen that anywhere in this thread, but ill take your word for it.