Worth upgrading Headers & cats on VE SSV?

[WogBoyz]

Daniel_89 how did ya go mate? end up getting ya zorst done yet?

 

[HEKYEH]

Personally. Save the money and get a cam. Pacemaker headers plus cat and install is 1400/1800 hpc. Cam is 3k.

How is it going to breath though if u put a bigger cam in it but can't push out thegas as the headers and cats are too restrictive??

 

[Nuddy989]

How is it going to breath though if u put a bigger cam in it but can't push out thegas as the headers and cats are too restrictive??

true story, 6.2L with our street cam is 320rwkw with standard extractors, put xforce 4 into one 1" and 3/4 2.5" extractors and it picked up 40rwkw with a new tune obviously.....

dyno proven day in day out ssv with otr and cat back about 225-230rwkw with tune... with extractors 250 + rwkw... standard ssv makes about 205-210rwkw....

 

[PIR4TE]

true story, 6.2L with our street cam is 320rwkw with standard extractors, put xforce 4 into one 1" and 3/4 2.5" extractors and it picked up 40rwkw with a new tune obviously.....

dyno proven day in day out ssv with otr and cat back about 225-230rwkw with tune... with extractors 250 + rwkw... standard ssv makes about 205-210rwkw....

Interesting, my L77 on E85 was 212 rwkw out of the packet, 218 with catback, 250rwkw & 550nm with OTR and tune (bonnet up), 253rwkw & 580nm (bonnet closed) with OTR mod using latest E85 AFR calcs in EFIlive, now with HSV extractors is 289rwkw and 620nm (bonnet down).
Obviously the headers delivered the benefit of increased Volumetric Efficiency to the E85 tune on the latest engine variant, L77. That translates to 12.5 seconds 0-190, good enough for me with 7.4 l/100k @ 116k economy.
Having spent nearly $mid90sRicer$ on licencing and tweaking tuning tables and three days expert dyno time to increase the L77's VE with just bolt-ons (specifically in aid of sustained high speed interstate driving), I say yes, get the HSV headers.
Change the cam and you change the heart of the engine, for me it's unlikely to get the same drivability and economy with a cam's bigger lift / duration shifting the power band up the tacho. Cheaper too.

 

[brad VE SSV]

Interesting, my L77 on E85 was 212 rwkw out of the packet, 218 with catback, 249rwkw & 550nm with OTR and tune (bonnet up), 253rwkw & 580nm (bonnet closed) with OTR mod using latest E85 AFR calcs in EFIlive, now with HSV extractors is 289rwkw and 620nm (bonnet down).
Obviously the headers delivered the benefit of 16% increased Volumetric Efficiency to the E85 tune on the latest engine variant, L77. That translates to 12.5 seconds 0-190, good enough for me with 7.4 l/100k @ 116k economy.
Having spent nearly $$$ on licencing and tweaking tuning tables and three days expert dyno time to increase the L77's VE with just bolt-ons (specifically in aid of sustained high speed interstate driving), I say yes, get the HSV headers.
Change the cam and you change the heart of the engine, for me it's unlikely to get the same drivability and economy with a cam's bigger lift / duration shifting the power band up the tacho. Cheaper too.

With what you wrote, did u use the hsv cat as well as headers or just L77 cats with hsv headers..

Cheers brad

 

[PIR4TE]

With what you wrote, did u use the hsv cat as well as headers or just L77 cats with hsv headers..

HSV headers, SSV cat... BUT... there's a bit in the detail: HSV header and cat is perfect fit bolts straight on head and catback, the obvious preference for the muffler guy, but don't do that.
The inlet (header flange to cat pipe) and outlet (cat to catback flange pipe) both need to be 2.5", so you are going to cut and weld cat anyway, so don't spend extra $$$ on securing HSV headers with cats. Save your dough and use the existing cats (same unit, just different entry pipes anyway).
They both qualify as hi flow, just ceramic core not stainless. Don't need any other cat than the ones you already have. See full mod details on this thread:
http://forums.justcommodores.com.au/showpost.php?p=2236625

 

[AD07]

I thought that the cats were the same...and that there wasnt any cutting or welding needed when matching it to the cat-back system.
Hence, the easy upgrade....you confuse me.:hmmm:

 

[PIR4TE]

Yes the cat body or 'cans' are the same but have different connecting pipes to bolt up to respective exhaust headers.
Point I was making is that it's simple to just replace SS contraption with HSV plus cats, but may as well mod to hi flow inlet and outlet (rather than buy new cats) while you're at it.
See pic showing L77 system front overlaid on HSV at back:

The SS header is short, requiring a long bit of skinny pipe bent at 90° to can at 45° join.
The HSV header has three Y joins of tuned length, being quite long by comparison straight at 45° join (see pic).
Hence shorter and more direct skinny pipe.
Both pipes are too skinny, cut at same 45° join location where the neck of the pipe meets the can. Replace with fat 2.5 pipe. While you're at it cut off the skinny outlet pipe and replace with fat 2.5 pipe too.

 

[PIR4TE]

I thought that the cats were the same...and that there wasnt any cutting or welding needed when matching it to the cat-back system.
Hence, the easy upgrade....you confuse me.:hmmm:

Yes is much easier to leave skinny pipe on HSV header, and prolly better than not having them, agreed. Just very few L77s can boast 289rwkw / 390rwhp with AFM. Join me.

 

[Turtle2388]

I wouldn't use ANY holden factory cat if you paid me! Have you seen the inside of one and how terribly they flow? A vcm guy showed me and had me convinced to never keep them crappy things!

Sent from my GT-I9300T using Tapatalk 2