Can Mugen 4-1 extractor fit B16a?

[crazievitek]

The 4-1 vs 4-2-1 debate again :P
My 2 cents is, 4-1 design allows you to gain max BHP at the top end, while 4-2-1 provides better torque at lower RPM's for good drivability.
The B16 engine comes with 4-2-1 coz it's a low torque engine, therefore it will benefit from that design. Otherwise the drivability of the car would suffer. Likewise, the B18 motor has greater torque, allowing it to use a 4-1 design without sacrificing drivability.
That's my take on the 2 designs. Now, don't shoot me if I'm wrong :P

 

[ace79]

You might want to read this:
http://www.zerotohundred.com/newforums/showthread.php?t=28686

i've read thru this posting..and still i dun really get it..other sifus can help out on this? i've read thru some automotive books @ Kinokuniya, and what I've learned is :

4 - 2 - 1 : low and midrange power
4 - 1 : some midrange but pure high RPM power

If I'm proven wrong, dun shoot me lah! I do find this quite important because I'm looking for one as well. I want to improve the B16A's low and midrange strengths, since the car is driven daily and not a track rocket. I believe that I can improve the B16A's top end ( if the monster motor idea is out of the window.. ) with a proper set of cams, valves, valve springs, retainers, forged pistons ( a wee bit bigger maybe ) and conrods.

 

[ace79]

from an uninitiated person's view :

4 - 2 - 1 : seems like a wee bit sempit and semput, since the exhaust gases are compressed from 4 pipes, into 2 pipes, and only later on to a single pipe.

4 - 1 : maybe better airflow, since 4 pipes go directly to a single pipe.

I might be right or wrong, I'm still learning this stuffs too. But from my experience from playing with bikes, 4 - 2 - 1 gives your low and midrange power, while a 4 - 1 system allows you to get more power on the higher RPM ranges. Basically a 4 stroke sportsbikes have almost the same mechanicals ( intake, throttle body / butterfly, injectors, cams, valves, pistons etc and so on... ) as 4 cylinder cars too... just my 2 rupees...

 

[hattech-v]

aiyaaaaaaaa....... wa sudah fenin laaa...

 

[Xenix]

aiya... get a good workshop which have good repu like Amoil.. And let the pro do the job..

 

[hattech-v]

we can go to any good workshop but we cannot simply get knowledge by paying them... then this is the place that we can share.... hehhhehehe...

 

[399]

i agreed... u can't trust one person 100%.

 

[hattech-v]

i've been experienced 4-2-1 n 4-1... what i can feel is 4-2-1 give more power on low range/mid range rpm n 4-2-1 give u top end/high rpm power...

 

[ace79]

Oooppppssss...typo error or what? ekekekeke...

i've been experienced 4-2-1 n 4-1... what i can feel is 4-2-1 give more power on low range/mid range rpm n 4-2-1 give u top end/high rpm power...

uiks...what is this...

 

[hattech-v]

typoooooooo... ekekekeke....
4-1 top end... hehhehe

 

[Riezal-R]

Haha so confusing lah. Let me share my experience (this might confuse us all even more):

Old car was running a standard-mod B16B engine, i used a B18CR 4-1 extractor (the B18CR ones are shaped like Mugen). Diameter was about 2.2-2.3 inch. From this i lost a bit of pick-up power but gained power at high-RPM. It also somewhat increased my top-end speed.

Then i changed to a B16A 4-2-1 FGK extractor. Diameter was about 2 inch. I gained a lot of pickup power and torque. I lost some power at high-RPM and the VTEC kick was not as powerful as before. But the amount of torque and low-end power I gained was worth it.

On both occasions, I tested with a standard DC2 integra running B18CR. Using the first extractor, i won by about half car. Mainly because I could rev at higher RPMs, but never really pulled away. Using the second extractor, i won by more than 1 car. And the difference was felt at every gear change. Because of the torque obtained from the extractor, every time i engage a higher gear and open full throttle, i pulled away from the DC2. Unfortunately, I didnt dyno the car, so there is no conclusive ratings.

Conclusion from this was, not only does the design of the extractor (4-1 or 4-2-1) matters, but the diameter of the extractor also plays a big part. I was reluctant to use a B16A extractor on a B16B engine, but for the price I paid and the power I got from it, well worth it.

Dunno if that helps you make a better decision or not. Just sharing.

 

[ace79]

wah, more info learned..thank bro Riezal-R!

Allright, now at the very least, we have some conclusion that we can say is, slightly correct, that is :

4-2-1 : is for pickup and midrange, and
4-1 : is for top end power.

Bro Riezal-R, is correct, size of piping is also essential in order to extract what kind of HP and torque are you looking for at certain RPMs. I've read this in a book titled "4 Stroke Performance " @ Kinokuniya KLCC, quite an old book, but a lot of knowledege is in it. It also got the calculations for you to do your extractor, pipe size and lengths etc.

I myself have gotten tired of going around, looking for a 4-2-1 extractor for my B16A EG. Someone did offer me a 4-1 system copied from Mugen ( Thai made, I believe ) but I don't want top end power, at least not now, as I believe that you can extract high RPM power from other parts of your engine. Since my car is a daily driver, I believe a 4-2-1 system is the best compromise for me.

Now I'm a bit worried when I read Riezal-R's posting. Loss of VTEC kick ( why I chose an over 10 year old Civic over a GTi R3 ) is quite worrying. I love the feel of the car when my VTEC kicks in at around 4800 rpm. Loss of power from high RPMs is also a bit worrying for me ( 'cause sometimes I drive up to 200 kph++ on the Federal Highway at late nights, ****** ma... ;) ) if I choose to go the custom extractor route, what size of piping should I go for? 2 inch? 2.5 inch? Or something in between?

If you are to choose the 4-1 route, what mods do one needs to do in order to get better pickup and midrange then?

 

[Riezal-R]

I THINK, i lost my VTEC kick because the diameter was quite small. Even when VTEC didn't open, there is already a lot or pressure/torque in the extractor. So due to the small diameter, couldn't really feel the VTEC kicking. But the low-end power made up for this. I believe a 2.2-2.3 inch diameter extractor for my B16B would have given a nicer VTEC kick. Not sure how it will be for B16A.

As to why I i got more pick-up power from the 4-2-1, I still think it was more because of the diameter, instead of the design of the extractor. Coz the same thing happened with my exhaust system. Changed from 2.3-2.5 inch to a 2-2.2 inch and felt more pickup.

And just to add, the B16A FGK extractor i used was a 2-piece 4-2-1 extractor. The bottom half had very slight signs of a small crack. I had that welded to strengthen it. Shop said shouldnt cause any problems coz it was very slight. After 1 day of using and about 7-8 runs of dragging the car, the bottom half of the extractor actually cracked open right down the middle. Pressure was too high inside and the welding couldn't take it. Luckily, I found a shop which had the bottom half of the FGK and i had that fixed. Reason I added this is to relate to how much pressure/torque there was in the 2-inch B16A extractor, used on a B16B engine (which usually uses 2.2 inch diameter). That's just my theory though.

 

[ace79]

Thanks for the details bro Riezal-R. If one goes for the custom route, to fabricate a proper 4-2-1 extractor, for a B16A, a requirement of around 2 inch diameter piping size is pretty allright ( I think so? Opinions? ) But since my B16A's head already been PnP'ed, should I still go for the same size, or should I go a wee bit more? Note : I don't believe local exhaust shops have such sizes, i.e 2.1, 2.2, 2.3 inch etc. Standard B16A's is 4-2-1, right? But I dunno the size of a standard B16A extractor..

I already have an RS-R's middle pipe and a 5 Zigen silencer ( both not yet fitted, and the quiet one I believe, since the muffler body, not the exit pipe, is pretty big in size ), but I don't have the proper equipment to measure the diameter of the pipe and muffler inlet. When I used a measuring tape, I got 2 inch ( measured diagonally, right in between, from the inside of both muffler inlet and middle piping ) Now is this sizing work well for my B16A? I should go for a extractor which have the same exit pipe diameter also lah, right? Can I still go a larger - sized extractor ( from the 4-2 piping ), then go slightly smaller ( the 2-1 part ) and 2 inch for the exit of the extractor, then follow up with the RS-R middle pipe and 5 Zigen muffler?

 

[Riezal-R]

Local exhaust shops will have the 2.2 inch pipes, as they cater for the demand. Lot of NA cars use this, plenty of MIVEC and VTEC around town. JFA @ Sunway definitey have it. IMO, only enlarge the extractor diameter when you have high performance cams or stroker kit or such major internal engine mods.

As for having different sized diameter on the 2-piece extractor, well I've seen people do it on NA cars. But I duno if they enlarge or reduce the size of the lower part. They call it 'downpipe'? It does make a bit of difference.

 

[ace79]

thanks for the info bro...now I'm quite pening oledi...should I stay with the current standard extractor, or should I go the whole hog and change it? Should I still fit the RS-R middle pipe and 5 Zigen muffler ( both have same 2 inch size, measured diagonally using a measuring tape ) or should I go and fabricate a 2.2 inch sized 4-2-1 extractor outlet and middle pipe? My B16A is still pretty standard, other than a PnP'ed head.

 

[hattech-v]

like that maybe u can give test n error... then share with us... hehhehe

 

[xxxx]

haltech-v, u tried 4-2-1 n 4-1 on whose car?

 

[hattech-v]

urs car laaa.... hahhahaha.... tomoro aaa... remember... dun play badminton again... hahhahaha

 

[xxxx]

wat time bro?