phxcobra

Has anybody with full boltons including H/C switched from 1 7/8 to 2" headers? If so, did you see significant gains?

walhan_qtr

Estewardii

I'm wondering this too.

spartanc6z06

Ive always asked this question. And took me 2 months to finally decide on 1 7/8 headers for my cammed combo. But, technically you should make more power at the top with the 2''. There just wasnt enough info for me to get them over the norm and 1 7/8 is enough header to support almost all combos. Unless i decide to spray over a 200 shot or run boost im keeping mine for full bolt-ons H/C. Just my .02

Geared

youll be giving up too much power down low IMO unless your running a HUGE cam, very worked heads a full fast 102/NW setup and a cf112 intake to feed the air....and even then youll probably be giving up downlow power....but your peak will be higher

fwiw, i would stick with 1 7/8.

there is a guy out of puerto rico running 2 inch headers, but he never posts his dyno sheets in SAE, so noone knows whether or not hes making more or less power than people with similar setups and 1 7/8 headers.

phxcobra

well, i've got a big cam and P&P heads withe mild milling, fast intake with NW going on soon along with E85 tune. The reason i brought this up is i read this for sale thread where the dynos show around 16hp/20tq gain going the bigger headers. granted the runs were on different days etc. And i understand you may lose some low end tq although this car didnt. So i was just checking to see if there were others that had made the switch and what their experiences were.


http://forums.corvetteforum.com/c6-c...h-608rwhp.html

lane_change

I believe Carlos from Vette-Air was going to do some testing with his car and 2" headers...not sure what the results were. I know I was asking him about it when I was looking to buy a new set of headers. He may chime in to let us know....his car is very worked over making 650-ish whp N/A with E85. I saw that for sale thread as well and thought WTF? I've never heard of any claims like that and I'm sure if it was common to see those kind of numbers that lots and lots of people would be stepping up to 2" headers, I know I would be.

double06

Tighten the ends with the AN fittings with O Rings - do I tighten metal to metal or like oil filter tighten hand tight then half a turn with wrench? The metal to metal seems like a lot or can not be done.

double06

put it in right place

FamousRR

I will post up ASAP. I have h/c with fast and nw 102. My 2" ar headers should be put on by the end of the week. I'll post results after.

phxcobra

Awesome. Please do share your experience and before/after numbers. granted it'll be different days blah blah but it'll still give an idea. Maybe driving/seat of the pants too. What headers do you currently have or are you on stock manifolds?

FamousRR

No problem, I will. Right now I'm running the lg 1 3/4". I wanted my car built to pull all the way to redline. That's what it does. Makes peak hp at 7k. So with the 2" you will get more up top, that's also what I was looking for. I know it will be hard to compare going from 1 3/4" to 2" but my friend who is a vendor on here and has a shop that built my car, has a z06 with the same setup as me. He is running the 1 7/8" so I'll post the difference. Should be nice!!

I'll also post up the dyno, it's pretty impressive

FamousRR

My cam is a comp cams custom grind-239/251. 110 lsa with .660 lift. Pretty big.

Also have fast and nw 102. And just got the halltech cf112 for my b-day.

lane_change

Stock heads?

FamousRR

Stock heads stage 3 ported and milled by wcch

lane_change

Sounds like a pretty solid build...definitely curious how the 2" does for you. I went from the 1 3/4" to the 1 7/8", added the FAST, sending the heads out to WCCH this month, adding a McLeod RXT clutch, and the intake over to a Superbee as well. I'll be running the E85 setup. Needless to say, I'm looking forward to seeing the improvements over my previous setup...and I will be curious how the 2" design effects your torque curve down low as well as your hp curve up high. I'm hoping to drop the car off next week for the upgrades....should be done by the end of the month.

FamousRR

Thanks am I'm going crazy waiting to get them on!! I would have loved to do e85 but here in so cal there are like 2-3 gas stations that carry it. So I ended up doing a 91 with race gas mix tune. It runs real good knock on wood. Once they are on and we get the dyno done, I'll post it. I'll also post with the 1 3/4".

MBR44

That is my car in the ad. Dan really pushed me to the kook 2" headers because he wanted to break that 600rwhp mark and I wanted more torque. I was worried about loosing torque by going to a larger header and he was dead set on using kooks rather than the arh's that I supplied but he proved me wrong. I liked what I got out of the kooks upgrade. I do have a hefty cam and love the headers. I know that ARH has jumped on board and they have a 2" stepped to 1 7/8 that looks like a good combo to keep your low end torque but open it up on top. I didn't change anything else. If I was keeping the car I would have gone to a cf112 and a nw 102 this summer then worked over the suspension. Give me 2 more years and I will be back in another z06 but for now the family comes first.
Here are the dyno sheets going from arh 1 7/8 to a 2".

juyanith

MBR44, I assume the difference you're talking about is between these two runs:

RunFile_018.drf - 7/12/2010 2:41:39 PM Run Type: RO Run Conditions: 88.11 °F, 29.10 in-Hg, Humidity: 30%, STD: 1.05
2006 Corvette ZO6
Max Power = 591.09 Max Torque = 507.31
Livernois Tune, Stage 3 Heads, Stage 3 Cam, Kooks, Stock Catback, LMS modded, Heads Milled .010, 93 Octane, Halltech CAI


RunFile_028.drf - 10/30/2010 1:51:44 PM Run Type: RO Run Conditions: 102.52 °F, 29.40 in-Hg, Humidity: 6%, STD: 1.05
2006 Corvette ZO6
Max Power = 608.70 Max Torque = 528.83
Livernois Tune, Stage 3 Heads, Stage 3 Cam, Kooks, Stock Catback, LMS modded, Heads Milled .010, 93 Octane, Halltech CAI

So you gained about 17 hp/21 ft lbs peak?

lane_change

88 degrees in July
102 degree in October

Where do you live? Australia?