1.8l (qg18de) Exhaust Size 2" Or 2.25"?

[QRI05E]

Hi Guys, as some of you may know the pulsar.org.au site has suffered a hardware failure and thats why i'm posting this question here.

Which exhaust size should I go on my N16 1.8L (QG18DE) Exhaust Size 2" or 2.25"?

Regards,

Sarkis

[unarmed_skyline]

i duno bout pulsars but with the skylines they come factory 2.25 but a higher flowing 2.25 is great for torque and mid range where-as a 2.5 is better for top end but will suffer in the bottom end, also ontop of the the noise level of a 2.5 is wa louder and more muffling is needed to keep it leagle.

i dun think that really helps you much but mabye it gives you an idea, best thing to do is ask a professional exhaust shop and see what they think

cheers Jarrod

[Eug]

2" would be my pick of choice for a 1.8L, unless you intend on seeing high rpm regularly.

[QRI05E]

Being a 1.8 with only 92 flywheel KW it would need to see high RPM to get it going hahaha

It comes with a 2" press bent exhaust system from factory with a small CAT, 2 centre mufflers as well as a large rear muffler.

The setup im getting is:

Hurricane 4-2-1 extractors, 2.5" Highflow CAT with 2" or 2.25" mandrel bent CAT back, resonator half way with straight through highflow muffler at the back.

I dont want the setup for loud sound, i want it for maximum performance.

I used to own an R33 GTST with a full 3" exhaust which gained 21rw/kw however on an N/A back pressure loss will result in poor low end power, therefore im just contemplating if the 2.25" will be too large and result in low RPM power loss.

Cheers

[GTS4WD]

WOOO!

PGA FTW!!!!

2.25"..

[QRI05E]

Yea i been told the 2.25" would be best at high RPM perhaps if i put a smaller muffler that will help in back pressure?

[SKiT_R31]

Yea i been told the 2.25" would be best at high RPM perhaps if i put a smaller muffler that will help in back pressure?

You don't want back pressure mate, thats a myth, you want as little as possible

but as for pipe size, the loss is due to not having high velocity exhaust flow, actually increasing back pressure heaps from the slower and therefore cooler exhaust, and making the engine have to work a lot harder to push the exhaust out, which is why you get a loss down low - instead of the almost vacuum you get with smaller piping that can actually pull the exhaust from the engine.

getting a mandrel 2.25" exhaust & extractors, with a high-flow cat and straight through mufflers, i doubt you would lose anything down low (but there wouldn't be a gain - vs the stock restrictive exhaust), and up top would be very responsive, but thats only if its going to regularly see top end, if its more a std daily, mostly kept in low rpm, 2" mandrel would be fine, and happily flows 100kw at the wheels, you would possibly get better low end economy from this, vs a larger diameter pipe.

if it was me... I'd probably get a 2" mandrel with a few hot dogs, maybe a mandrel center offset or straight through, something high flowing that wont sound like a tin can, and if you were in new Zealand, a pipe where the cat should be, otherwise high flow. That way the exhaust will flow freely, and happily at high speeds through the smaller piping, esp with some decent tuned length extractors.

but then it does depends if you want to work the engine any more

[QRI05E]

Thanks for the advice! I think i will stick to the 2" exhaust, as you said it will flow more then enough for 100kw ATW.

[Mrs Mad082]

just go 2". my has a 2" (stock is about 1 3/4 or 7/8) and it made 112fwhp. it is genie extractors, stock cat and shitty 2" press bend cat back. and it revs all the way out to 7500. i didn't really notice any gain from the exhaust but i noticed a huge gain at high rpm from the extractors.

people with the 2.25" system don't really gain much, and it is only at high rpm that there is any gain. at lower rpm both the 2 and 2.25 will flow about the same.

Edited September 12, 2007 by Mrs Mad082

[QRI05E]

As stared before, im wanting total power gain through out the RPM range. Even if the 2.25" will add another 5fw/kw over the 2" at high RPM then its worth getting...