C6superchargedrandy

I recently found a crack in my previous set of headers, so I'm in the market for a new set. I'm running a stroker with an F1 and putting down around 850 to my wheels. I know this has been beat to death, but I need input on which headers to run for my application. 1 7/8 or 2"? Right now, I obviously have more than enough top end, so I wouldn't mind picking up some midrange torque, but I really don't want to lose up top either. Has anyone tried the new Pfadt tri-y 1 7/8 headers in a big HP car? How about their 1 3/4 with a FI application? Did you pick up any mid range TQ? How much peak HP did you lose? How about ARH 2"? How much peak did you gain using the 2", and did you lose any torque through the midrange? Any other options I should look at?

Thanks for the input!

autocross_mitchell

Pfadt has 1 7/8 headers?? Last I checked they only had 1.75

Unreal

ARH or SW 2" would be my suggestions.

The pfadt are 1 3/4" for corvette applications.

jon6.0

I would do the larger Pfadts that are offered now. I bought the 1 3/4 when they first came out.

Yes Pfadt has larger primaries if you ask to have them built. Secret squirrel type stuff going down, lol. They might even have 2" now. Call them up.


12 psi with a T trim in 117F heat. 11* timing.

C6superchargedrandy

Will I lose any low/mid?

jon6.0

See my post above.

C6superchargedrandy

So how do your mid-range/peak numbers compare to a 1 7/8 with a similar build?

jon6.0

The only thing offered at the time for Pfadt was 1 3/4. You can now get larger primaries. That's what I would get at your HP level. Not my 1 3/4, especially since you have a stroker. I think my car makes good power compared to similar builds, but I will have a better feel for it once we can put full timing in it with meth. 4-5* more timing should put me in the 725-750rwhp range. About what most ECS1500 and A&A T trim's do with a cam and small blower pulley.

spwz06

http://store.pfadtracing.com/c6-corv...7-8-with-cats/

Unreal

Says will be released 9/15. I'll be interested in the results.

Ls2_robertdrewrose

about time, they should have done it from the start. More flow means more power. for a company that is suposed to be smart engineers, I'm not impressed. I would go with the 2" ones

Unreal

I think they just underestimated the amount of vette owners that want to make 700+hp. 1 3/4" are fine for ls2/3 and mild ls7 setups but when it is getting common to see 700+ out of ls7s and built motors I think this is a good step forward.

jeremy_sanchezC6

Ever heard of scavenging? "more flow means more power" is probably the dumbest thing I've heard today. Power increases come from scavenging. Obviously we don't want any flow restrictions, and you aren't getting a major restriction with a 1 3/4 or a 1 7/8. What you are doing by changing the sizes is shifting your peak TQ curve forward. At a certain point you will create a restriction, and a 1 7/8 will probably have a better top end. That point it probably around 800rwhp though with most header designs. For the OP, I bet at your power level you will want the 1 7/8. Honestly though, with such a monster top end, I would still go 1 3/4 to get more mid-range tq. You already have a big enough peak

spwz06

Agree about flow. With their try y the 1 7/8 will flow just as good if not better than a 2". I'm excited to see how much more torque they grab down low though.

Erics_02_z06

The Pfadt headers are amazing. I've seen the 1 3/4 used up to 600+ RWHP, and the TQ comes on earlier and stronger than any other header. For a FI, get the 1 7/8. It will flow like a 2" but give you a lot more torque down low

jon6.0

I'll have my shop talk to them about swapping my 1 3/4 Pfadt for the new 1 7/8 and doing a back to back dyno session the same day with optimized tuning for the bigger headers. If they cut me a deal I'll do it.

I'm already at 673/584 with 11* of timing. Not sure how much better they will be. Adding the meth kit this Tuesday and will probably be around 720-750rwhp and 15*-16* of timing after that gets done.

peter pan

On my built LS6 I gained 7hp/9tq going from 1 3/4 to 1 7/8 only a few lost down low could not tell any difference anywhere just liked my AR sounding ones better than the Stainless Works.

jon6.0

At what horsepower level? Because 7hp isn't worth it for the money involved in swapping.

peter pan

I went from 742RWHP to 749RWHP, so for power it was not worth the $$.

gotjuice?

He was at your hp level. D1, meth and built 9.5 comp engine, C5 Vette. We changed from TPIS 1 3/4 to AR 1 7/8 headers with Stainless Works 3 inch muffler cat back.
I change from AR 1 7/8 to AR 2inch and double my hp, Also change the engine setup.