H-Pipe, CANT FIND ANSWERS....Come in please

[c4fly]

Ok, I have looked page by page up to 88 pages deep on the exhaust forum last night, thread by thread, even used the search button and Google searched the hell out of this and cant find the answer. :shrug:

So, here it goes.

The 03-04 Cobra stock H-pipe, realistically how good is it?
How much of a restriction is it, really??

I have seen 03-04 Cobras with stock h-pipes, pullied, ported blower, cat back, RAI, tuned, dyno over 500rwhp. W/O ported blower 470-480rwhp.

Going to a O/R X, H, or Prochamber mid pipe (I know there is not a huge difference between them in terms of power gains and read mostly sound difference) I have read that there is only 5-10rwhp increase (w/ an Eaton Cobra no Whipple or Kenny Bell), and some loss of torque, over the stock H-pipe.

Does anyone have any experience and dyno numbers with the stock H-pipe then an O/R mid pipe? (H, X, prochamber, doesnt matter to me as long as there are no cats)

No highflow cats comparison or Whipples or Kenny Bells. Just stock H vs o/r with Eatons.

 

[moot09]

Well my car dynoed 455/454 on a dynojet with my stock h on 93oct with the previous owner. Once I had it retuned for 91 and an o/r x I dynoed 440/435 on a dyno dynamics dyno

They dyno roughly 6-8% lower than a dyno jet I believe. So give or take I picked up around 10rwhp and 5rwtrq. Nothing very noticeable though.

 

[c4fly]

Thats kind what I was thinking to.

Does anyone else have any input?

You mean there is no one out there that has done an experiment with this?

 

[moonltgold]

Went from a stock H to a Magnaflow catted X on my old Cobra -- no other changes and dynoed both. Mag was worth 3 rwhp more. So the stock H is pretty good. The real HP gain with these cars is in the catback -- I went from stock to a Bassani catback and got 20 plus rwhp.
(On another exhaust subject, I dynoed back-to-back and gained 15/15 rwhp and torque at peak with a set of highly modified (ported, re-fabricated) JBA shorty headers -- although the stock manifolds are pretty good and now I'll need to retune because running too lean.)

 

[346CamaroSS]

Interesting topic.. Sub'n

 

[c4fly]

Went from a stock H to a Magnaflow catted X on my old Cobra -- no other changes and dynoed both. Mag was worth 3 rwhp more. So the stock H is pretty good. The real HP gain with these cars is in the catback -- I went from stock to a Bassani catback and got 20 plus rwhp.
(On another exhaust subject, I dynoed back-to-back and gained 15/15 rwhp and torque at peak with a set of highly modified (ported, re-fabricated) JBA shorty headers -- although the stock manifolds are pretty good and now I'll need to retune because running too lean.)

Wow, really. I guess the stock H-pipe IS pretty good! I have a prochamber on my car with Magnaflow Cat back with Macs bolted in and I am highly thinking about going back the stock H-pipe because of California Smog Laws and the Cops out here are dicks! They will pull you over for anything and get REAL nosey.

The stock H-pipes for 03 and 04, are there any differences?
Can someone post a pic of each one?

 

[moonltgold]

Wow, really. I guess the stock H-pipe IS pretty good! I have a prochamber on my car with Magnaflow Cat back with Macs bolted in and I am highly thinking about going back the stock H-pipe because of California Smog Laws and the Cops out here are dicks! They will pull you over for anything and get REAL nosey.

The stock H-pipes for 03 and 04, are there any differences?
Can someone post a pic of each one?

The '04 has longer cats in the two rear locations. You can still use an '03 H-pipe with them just get the O2 bung extenders. Other than that they are the same.

 

[c4fly]

Moonlt, what year was your Cobra?

The info you gave is very god to know. I have seen both side by side and they look different. The 03 Cobra stock h-pipe has less bends in it and the secondary cats look smaller. I would think that maybe an 03 would flow just a tad better than an 04.

 

[moonltgold]

Moonlt, what year was your Cobra?

The info you gave is very god to know. I have seen both side by side and they look different. The 03 Cobra stock h-pipe has less bends in it and the secondary cats look smaller. I would think that maybe an 03 would flow just a tad better than an 04.

Mystichrome (2004)
Maybe a hair better flow on the '03, but quite similar. I modified my '04 midpipe behind the cats to run 2.5" OD and a large 2.5" crossover, so it outflows anything stock. Give me your email and I'll send you pics (before and after mods).

 

[c4fly]

Pm sent