ok well now ive been discussing this with Unsung EM1, but im still a little boggled.

i have a 96 ls, with a dc 4-1 header that came on the car when i bought it along with the exhaust. (tanabe racing medalion). Ok well what is the carb plate? and im not understanding that with my ehxuast and header that im not making and useable power, with this exhaust setup.

 

a dc 4-1 header and a racing medalion helps to make useable power on your car...other setups could be better, but without any big-time modifying, your setup is sufficient

 

so what would u suggest as a better setup?

 

header: SMSP, Hytech, Comptech (the new one), Toda, or Spoon
cat: Anything 2.5 inch (most ppl use carsound)
exhaust: SMSP, Hytech, Type-One or custom mandrel bent 2.5

 

meh.... i think i will save the money for a turbo and new valves/srpings before i spend the money for a new header that will only give me a little more performance at the price of those listed.

and as for exhaust, well im tired of my trm. its too loud.


but back to the topic.... im still curious how to tell teh difference between the jdm and udsm 4-1 header. Unsung said ther was no carb plate on the jdm but whats the carb plate?

 

The JDM DC header has a 2.5" collector where the USDM version is 2".

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Champ R &raquo;</TD></TR><TR><TD CLASS="quote">The JDM DC header has a 2.5" collector where the USDM version is 2". </TD></TR></TABLE>
isnt it 2.25 ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GettaluvR &raquo;</TD></TR><TR><TD CLASS="quote">
isnt it 2.25 ?</TD></TR></TABLE>

No, all the usdm headers are 2". I have no idea where this 2-1/4" info came from. The ITR has a 2-1/4" exhaust but only after the 1-3/4" ID bottleneck after the cat.

 

I actually just measured a usdm dc header and it was 1 and 7/8 inch.. Way smaller than a dc jdm

 

Carb plate is the little plate welded onto one of the primary tubes near the head. CARB is California Air Resources Board. When something is CARB approved, the CARB issues a number that can be looked up in a smog check manual to see that it's legal so that the smog tech can pass the car. DC U.S. 4-1 is CARB approved, the DC JDM 4-1 is not, so it does not have the plate.

 

something I've been wondering is between the jdm and the usdm. are the primaries the same? is just the collector the thing that is different?

 

jisecup, the reason people recommend an SMSP, DTR, Header-Tech, AN-R or like header, is because it's not just a "slight" improvement over a USDM header, it's a gigantic improvement. For example, Pacman ITR. On a stock ITR motor, he gained 22whp from an SMSP header, whereas if he were to put a USDM DC header on his car, he would have gained maybe 2-3whp.

Unfortunately a lot of people have a misconception that bolt-ons are bolt-ons, and the real power is made with internals. It couldn't be more opposite, as an SMSP header generally makes more power than a good set of cams after tuning.

I hope this helps clear things up a little.

 

I've had bot headers on my R. & both with the N1 catback on the car. Going to the 2.5" colletor header along with a carsound cat was a considerable increase of performance from the USDM header.

 

so if i were to get a whole exhaust setup 2.5 all the way thru i would considerably increase my power?

what would a b-pipe do and what exactly is it?

yeah thsee are kinda noob questions, but i wanna know this stuff for futre references.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jisecup &raquo;</TD></TR><TR><TD CLASS="quote">so if i were to get a whole exhaust setup 2.5 all the way thru i would considerably increase my power?</TD></TR></TABLE>

2.5" exhaust would help, but most of the power would be made in the 2.5" header. Remember, you get what you pay for.

 

You guys all realise this is for an LS, right?

I'm not so sure I'd be recommending 2.5" collector headers for the non-VTEC motor, and before recommending an exhaust system that costs $2,000 from the head to the bumper I'd probably suggest a ligitimate motor swap. I'd rather have a B18C with a stock manifold than an SMS-equipped B18B.

As for headers for the B18B, I'd prefer the Comptech or DC 4-2-1 with the 2" collector. They have great ground clearance, bolt on easily, are CARB-legal and save a good ~15 lbs. compared with the stock US manifold. I suspect power differences between the DC 4-1 and the DC or Comptech 4-2-1 won't be much, but the 4-2-1 may provide better midrange power (you'd have to dyno to be sure, though).

 

Remember, the b16 may make more hp, but it also makes less torque than the b18b. Point is, b16's have shown good gains with a 2.5" system over a 2". It really boils down to what your goals are though. If you want to build a real street machine, then I agree, swap a b18c in there. In reality, that'll maximize your performance per dollar for that car.

 

Yes, it is possible that a 2.5" system would make a bit more hp than 2" on a B18B, but I'd be very surprised if the gains were as significant as they are with the B18C. I don't know, though. I've never seen the respective headers tested on a dyno. All I'm saying is that I wouldn't spend too much money on modifying a B18B because IMO a stock B18C is a better engine to have.

As for the B16A, I'd expect it to be flowing a larger volume of air at redline than a B18B at redline, despite the B16A being 200 cc down on displacement. The B16A has larger ports, much more agressive cam specs and an 1,200 rpm higher redline.