imadesign

team,,,
frind of mine has 2GS with custome headers installed on it and he reported that its not that expensive to make it. he has just the headers made with cateletic converter installed with the oem midpipe and oem mufflers. iyou can hear the engine breathing easly
i went to have a look on my 2006 GS300AWD, found that the space to make the collector is very short befor the cat.
what do you think guys if i go ahead and make the headers with a small collectot like 6"long with the cateletic converters and install the oem mid pipe with the oem mufflers since im not a big fan of loud noise..does it worth it??
or at least keep the muffler and change the mid pipe only??

designo

iTrader: (6)

Your friend should have the blueprint from his fabricator!

Ap1_Alan

iTrader: (1)

You probably won't see much, if anything, in hp gains.

designo

iTrader: (6)

I disagree completely, on a naturally aspirated car, the most power gains you are gonna get are from unrestricting, and also redesigning exhaust manifolds.

If you can couple that with a good software map to adjust A/F ratio along with ignition timing, you can easily get 30 to 40whp gain!

Ap1_Alan

iTrader: (1)

I know in your area the GS came detuned, so you have potential to see drastic improvements with just a tune.

But show me anyone that has got 30-40whp gain on a GS with a header

To address his original question, i still stand by my statement. Headers alone will not give him much/any gain. His exhaust will still be bottle necked at the cat, stock mid pipe, and mufflers.

If he were to change the whole exhaust system, and find a way to tune it (which isnt easy or cheap on these cars), he could see some improvements. very unlikely to see 30-40 whp.

imadesign

headers it self has some hp gains even though its bottle nicked in midpipes and mufflers,
the differince between the oem manifold and the headers is that the headers has the collector which helps extracting more smoke/ exhaust by using some kind of science called the berlony effect i guess this is how you write it??

Ap1_Alan

iTrader: (1)

Some, yes, but not much with header alone.

PPE headers claim to make 16hp on the is350 (so a gs350 should be similar), however the test car also had INTAKE and FULL EXHAUST. The PPE headers also have NO CAT. By eliminating the cat in their design, they can run longer primary tubes which will give more top end power, not to mention eliminate the air flow restrictions of the cat all together.

Another thing you'll have to consider is your states smog requirements. In CA, where i am, you'd never pass the visual inspection unless the header has a carb legal stamp.