swoody

Ok, my car currently has stock heads and internals, and QTP headers with the 1-7/8" primaries. My question is, will the 1-7/8" primaries gain me any more power over the regular 1-3/4" QTP's? Or since I'm running stock cubes, would the 1-3/4" primaries give me better performance? I'm thinking about trading my larger headers for someone who has similar QTP's but in the smaller size. Would this be worthwhile? What do you guys think? Any proof to support your ideas would be great help, too! Thanks for looking.

Woody

2001ws6-500hp

the 1 3/4 would perform better for your setup. but not enough to be worth all the work swapping.

swoody

What if I picked up a pair with the high-velocity merge collectors? Would those be better than my 1-7/8" without it?

RJB01camaross

If you do a search there was a dyno comparison posted a while back. If I remember correctly there was a power increase in the upper RPM's and no loss down low with going with a 1 7/8th over a 1 3/4.

swoody

Ah, thanks for that tip RJB So you're basically saying they are both even in lower RPM's but the 1-7/8" headers will give me more power up top? I'll try searching, but do you happen to know the link to that?

swoody

And that was on stock heads/cubes as well?

jmilz28

iTrader: (13)

I have 1 7/8 ARH, I put down 342/355 on big 17x11 repops and a conservative dyno. So long as you tune the car, there are gains everywhere. There's really no downside at all. Completely stock internal 98 car with lid, LS6 intake, and SLP dual dual.

2001ws6-500hp

i knew that there was an increase in only the upper rpms, i must have been thinkin backwards, still alotta work for a couple hp.

HTX

iTrader: (1)

this has been an on going argument for the past 2 years (at least) on this site.
In theory the smaller primaries provide more torque in the lowers power band whereas the larger primaries provide more torque in the higher RPM.

Noone has done a side by side comparison of the same brand on this site.
However TSP compared Hooker's 1 3/4 with TSP 1 7/8. TSP's provided same lowend with 5 more HP up top.
The problem with that comparison was that was two different Header designs.

WSsick

iTrader: (13)

yeah, the TSP comparo is about as close as youll get. id say its a pretty good test though. there wont be considerable differences that youll feel. if the TSP test is right, theres no real reason to change. plus, why not keep them and if you go H/C youll have a very nicely breathing engine?

LS1crazy01

iTrader: (14)

Yah X2, just keep them.

swoody

Yeah, after reading over everything, I think it's a pretty obvious choice for me to keep these puppies
Thanks for all the advice guys!