Singapore Rotary Performance Parts Reviews ….. RE Amemiya | Autoexe | Knight Sports | Greddy |

Exhaust Theory: Tuning Guide for Aftermarket Exhausts

I’m going to say it right out. Modern, post 2000 cars with small engine capacities (1.8l and below) should NEVER EVER install aftermarket exhausts if you want a speed increase (the Renesis 1.3l is an exception as displacement is nearer to 2.6l). You’ll get better sound no doubt, but you’ll never have more than just a couple of percentage points in bhp increase, if at all.

Aftermarket exhaust systems worked wonders for older designs such as the Corolla for a simple reason – the stock exhaust setup was crap – it had very small pipework that strangles the flow – just so that Toyota can get the fuel economy and emissions they advertised. So anything that made the pipes bigger and gave better flow did wonders for the Corolla.

Nowadays manufacturers can’t afford to throw away any spare power or fuel economy and modern exhaust systems are highly efficient “straight through” systems. Manifolds are still usually cast iron for durability but with longer runners and twin outlets that then lead into a long twin tubular downpipe. In essence it’s a productionised version of the tubular 4-2-1 performance manifold.

Exhaust systems really do help in higher capacity engines, and especially where exhaust gas temps are very high – that’s why aftermarket exhausts really do work for highly modified cars, race cars, and especially so for the hot Renesis engine. One thing that stops peak performance of engines is overtly high internal temperatures, and that’s usually caused by restrictive manifolds and exhausts – this especially becomes an issue in forced induction or lean stoich situations. So what’s recommended? A proper 4 branch tubular manifold and straight thru silencers.

But beware of systems that boast bigger bores / pipe diameters and all that rubbish. Lose the finely tuned bore sizes that manufacturers intend to be and you’ll lose power – it’s a factor of mathematics.

So what does RXReviews recommend? If you own an RX-8 or any other performance car,

  1. Keep the pipes stock. Dun fuck with perfection
  2. Change the muffler to a proven Jap rotary tuning brand – Autoexe, knightsports and RE Amemiya are good bets.
  3. Change the catalyst to something that improves flow, WO changing bore size or destroying your emissions. the Knightsports metalit catalyzer is a good one to get
  4. Change your manifolds. Here, I’m recommending RE Amemiya – race proven on the 4AT.

If you own a typical 1.6l car, don’t bloody waste your time. Do not kuitao at Man, Do not change pipes at Fong Kim, Do not get aftermarket exhausts from Supersprint, Remus, etc. Save your money and just get yourself a good dinner at Morton’s with foie gras or something.


September 25, 2006 Posted by | Exhaust | 8 Comments

RE Amemiya Exhaust Manifold

Singapore’s first RE Amemiya exhaust manifolds for the RX-8 is arriving anytime this week. RXReviews will bring you the review of this sweet performance mod as soon as it’s in – and for the 4AT!


September 5, 2006 Posted by | Exhaust | Leave a comment

Review: Knightsports Muffler for 6MT

Original review by Rei (http://www.rx8club.com/showthread.php?t=96986)  

Juz installed the knightsport muffler on saturday at monster garage. Initial feel
abt the muffler is that it is 1 hell of a gd muffler…(edited)

Let me start by saying, I wasn’t disappointed by the muffler…in fact, I was
impressed…after installing the muffler, the car now feels slightly more
responsive…If I wasn’t mistaken, the muffler does give a 7hp…plus the fact that
it is also lighter that the stock muffler…my guess is a combination of these 2
factors allowed me to feel a significant improvement in performance…the car now
lurges forward a little more willingly instead of the usual ” dun look at me…i’m
only a 1.3l rotary engine without any turbo inside” kind of lurge…

As for the sound, I wldn’t say it is a very loud muffler…during idling, I almost
thought i was still running on stock…but I think this is the kind of muffler that
require to be run at a higher rpm for it to sound absolutely lovely…but the true
beauty of the sound wld come in at say…ard 3k rpm? Anyway, thats what I felt…
above the 3k range…the exhaust starts to sound a little louder n a little more
bassy than b4…n as u start to rev higher, the sound juz simply starts to
compliment the engine. I say it enhances the sound of the rotary…n at 8500 rpm,
BOOM….magic…but I do have to say, this is not an exhaust for loud sounding
muffler fans coz even at very high rpm, it is still not as loud as some of those
flow thru muffler u heard on ur civics…It is juz not the typical “hey…wake up
neighbour, I’m home n I want u to know it coz i got a loud exhaust n its time
for u to go n pee b4 u embarass urslf by wetting ur bed” kind of muffler…

The look of this muffler is very similar to stock…except for the slightly bigger tail
pipe wif a knightsports wording engrave on 1 side n it protrudes out a little more
than the oem muffler…not very attention grabbing but hey…no one wants to grab
the attention of the wrong pple…for example, our very hard working ROV

Ok now, lets conclude…

Gains: 7hp
Weight: dunno…but definitely lighter than oem
Psychological Gain: Approximately 100hp
Damage: Kindly approach Monster Garage for a quotation

Lastly, I wld like to thank Monster garage for the product n the installation
process…the muffler works great…abit pai seh though…when Ivan help to
install it on my car…Buy u milo ping next time I c u, bro…thanks…
Oh, by the way…I was really proud of how my car sound b4 a yellow ferrari
zoom past me…
But hey…If I really wanted to sound like that, I want have installed microphones
n speaker to my tailpipes, right?
What more can I say…I’m a happy man…

August 28, 2006 Posted by | Exhaust | Leave a comment

Review: Autoexe Stainless Muffler (2 Box for 4AT)

Just installed my spanking new Autoexe Stainless Muffler, and here’s a short take of my initial impressions:

The Autoexe catback is lovely – very unique 2 box design and the tips are the tapered kind (ie cut at an angle) each lasercut with the Autoexe logo. Very nicely polished midpipe which connects beautifully (and easily) with the exhaust outlet. Most importantly, the exhaust tips have a perfect visual alignment, unlike other exhausts i’ve seen where one tip protrudes out more than the other. The Autoexe definitely doesn’t have this problem. Also, the 2 box design has a lower profile than stock. Previously, i used to scrape and even dent the exhaust box when clearing humps or even parking – not so with the Autoexe.

HP/torque increase:
Now I’m not really one of those ‘wake up the neighbours’ type of guys that go for loud exhausts, and would rather have a muffler that improves my ride’s performance. Now this is about the 3rd AT car i’ve owned in the past 3 years ( a Honda Civic, and then a Mazda 3) and i’ve tried about everything from ‘kui-tao’ the muffler at Manz, getting Sebring catbacks, changing resonators, pipe sizes etc etc. In fact, for the 8, this is the first time i’m getting a jdm brand.

From my experience, and also that of my previous club buddies, ATs are really hard to ‘tune’ exhaust-wise. You’ll either get no benefits other than sound, or even lose HP/torque. This is as a certain backpressure is needed to generate torque. In my Mazda 3, i once had a straight through setup with an increased pipe size, and it totally killed my low end torque.

The Autoexe performs really well, at least on my AT. There is a noticable increase in low end torque, and the car just feels substantially lighter. Revs are much more responsive, and the slight lag felt when launching the car seems to have melted away. Linear acceleration is also much faster (at least across 1st 3 gears), and i’m reaching 120-130kmh much faster on 2nd gear alone (NB mine is the 4spd AT). I’m very pleased with the low-torque gains on the Autoexe – finally i have that slight ‘lurch’ from start which the manuals seem to have, but the ATs don’t.

As mentioned earlier, if you want those really loud exhausts, look elsewhere. The Autoexe starts off idle with a really low, bassy growl. When first installed, it was barely audible, but sounds louder now. In time, the db will increase to an extent. On higher RPM revs, exhaust sounds deep and wet, and def not those shrilly Remus’ we hear on the expressways from time to time. Think of a younger Pavarotti, low but not overtly bassy, and definitely not as high pitched as Jose Carreras.

Installation was a breeze, and took under an hour at Monster Garage at Ubi, who’s the only authorized dealer in Singapore, so these guys know their stuff. Now what i really like about the installation is the care and time they take to make sure stuff goes up properly, it’s almost like they’re installing on their own cars. Now if you’ve ever experienced the crap service at FK and other exhaust places, you know what i mean.

Overall impressions:
The torque/hp improvement was a shocker esp on low end, esp when mine’s an AT. I’ve heard of bros installing Fujitsubos and HKSs that have either no or negative benefit. In this respect, I’m mighty pleased with the Autoexe. Sound is not loud, but a soft low bassy growl when idle, which develops into a mature wet sound at higher revs. The only other exhaust I know which works great with ATs is the RE Amemiya steel muffler, which is also available only at Monster Garage. The RE from what I heard has a very unique kind of sound.

I’ll post a further review on the sound once it breaks in further, what happens at higher speeds and hopefully, dyno results.

Low-end torque: 4.5
HP gain: n/a
Sound: 2
Looks: 4
Installation: 4

Available in Singapore with JASMA Cert from Monster Garage

August 28, 2006 Posted by | Exhaust | Leave a comment