bjII SP20 Exhaust questions

[DB0984]

I have been getting some mixed answers in my journey around the local exhaust shops. System will be from the engine back.

Headers >>>> Hiflow Cat >>>> Resinator >>>> Muffler

1. is the stock pipe MS or SS?

2. is it best to go 2.25" pipe? Had a guy tell me it will just make the engine work harder to push the gas out the bigger pipe, thus the fule consumption will go up.

3. what headers work best Pacemaker or Hurrucane?

[arden]

1. Mild Steel
2. 2.25" is optimal size
(due to EPA, my exhaust is now AWR Header---Magnaflow Cat---2" piping to rear axle with 2 resonators----2.25" piping to Magnaflow Muffler.)

3. No idea.

[chicaboo]

RedAstina had the same setup that Arden does now, but he had OBX header instead. Mitch made some decent power with that setup, and it wasn't that loud either. But 2.25" right through works well on the SP20 without getting crazy.

Fuel consumption actually goes down with less restriction (ie: bigger pipe), been there and done that...

Gav.

[arden]

my fuel consumption actually increased after i got exhaust.
Adding the magnaflow made it worse.
I now get 520km from full tank....

[chicaboo]

Originally Posted by arden

my fuel consumption actually increased after i got exhaust.
Adding the magnaflow made it worse.
I now get 520km from full tank....

That's cos your loud canon was less restricted.

I've gained significant fuel economy from just getting ram air to my stock intake. This was becuase I took the grill out to find a rattle and to mod the grill, finding a positive from driving around toothless was nice.

[DB0984]

Thank guys.
I thought i was MS but the guy was addamant (spelling) that it was SS. Same guy wanted to leave the stock pipe. Dont think i will be going to him.

[chicaboo]

Your stock pipe is 2" crush bent s/s. You could leave it, but you would atleast want to cut out the small cat and the bends and replace them with mandrel bends. It really depends where you want your power.

[DB0984]

So is it S/S of M/S?

Originally Posted by chicaboo

Your stock pipe is 2" crush bent s/s.

Originally Posted by arden

1. Mild Steel.

[chicaboo]

Ummm, my old stocko exhaust was s/s, it's just dull and not the shiny bling 304 grade stainless...

[DB0984]

Thanx Chica

How are the lights going? Got any spare time yet.

[chicaboo]

Nah, not had time to play around with lights yet, maybe this weekend if I finish my 6 story building... Sunday might be a goer?

[madaz sp20]

Just got mine finsihed up today

Pacemaker 4-1 extractors
2.5" flex for a 2.25" ID
2.25" high flow cat
2.25" mandrel bent piping
2.25" resinator
2.25" mandrel bent piping
hurricane muffler
4" tip

Worth it yes, no dyno yet wish I had a before mark anyway, driving around the acceleration is noticeably smoother and a lot harder. Only thing is it will be getting a different resinator when I get back to brisbane, too loud.

[chicaboo]

Resinators can be a placebo, Arden did well with his, but it's probably a baffled type and not a straight through design. Another thing you can consider is an in-line muffler instead of resonators. Just some thoughts.

[woofy]

Originally Posted by arden

1. Mild Steel
2. 2.25" is optimal size
(due to EPA, my exhaust is now AWR Header---Magnaflow Cat---2" piping to rear axle with 2 resonators----2.25" piping to Magnaflow Muffler.)

3. No idea.

What were the EPA probs?

[arden]

Originally Posted by woofy

What were the EPA probs?

http://www.astinagt.com/forums/showthread.php?t=7968

[project.r.racing]

not a EPA problem but transport/police issue. you exhaust is legal in very environmantal way. but a social issue, it is too loud.

about the only thing on an exhaust that has anything to do with the EPA is your catalytic converter.

ryan