I was having wings and beer after auto-x yesterday with some of the guys. Two of my buddies who also have '08 CRs like me, told me the T1R Sparrow exhaust makes an extra 15hp at the rear wheels.

Can anyone confirm or deny this? Feedback would be appreciated. It seems too good to be true. Thanks.

-Frank

 

No bolt on to our car, untuned will give you 15rwhp ESPECIALLY not a dual exhaust. 4-5rwhp at best

/thread

 

QFT!

When someone shows you a dyno of an exhaust in which 15whp has been made, they are most likely not telling you that it was tuned as well.

To date, there are only 2 exhausts I have seen which made that power; ASM 70mm and the J's Racing 70RR.

 

"TUNED" is the key

add the T1R 70mm single to the above list.

 

I personally think just about every aftermarket catback is a glorified grapefruit shooter, with a few exceptions of course. I will NEVER understand the need for any piping or outlet that is larger than the manifold or cat I.D., even worse a 3.5" tip for a 2 3/8" pipe.

 

Fixed also 1 thing all those exhausts have in common are they're unresonasted, straight HEADERBACK exhausts.

All to do with how exhaust flows (in pulses) and the key is to get them to line up and follow each other, so the pressure from the previous pulse "pulls" the next pulse through the piping to increase the exhaust velocity.

Since the pulses come out faster, larger/ slower, smaller depending on what rpm your at no one size pipe will be optimal at ALL rpms, it's physically impossible.

70mm (2.75) has been shown to make the best over the widest rpm range na power, 3" (76mm) will make more in the upper rpm range but will sacrifice low and midrange gains, if not lose power.


FYI the collector is usually 65mm so bigger than collector tubing is beneficial; tip size however is purely aesthetics.

p.s. I think this should be in the na or mods forum, not racing.

 

The only thing that aftermarket exhausts may do are minimally lighten things up a bit.

To some, dropping 10-20-30 lbs from the car is worth it in conjunction with other things done to lighten the car.

--kC

 

I have to plead ignorance on this topic. When you say dual exhaust, I'm not really following how the dual vs single thing affects power. This car deosn't have true dual exhaust cuz it's a 4 cylinder and has only one exhaust manifold. I was under the inpression that the 'dual' mufflers behind the cat were for cosmetic purposes.

if there's a discernable difference in cat-back performance between single and dual pipes, then why put dual exhaust on a performance car in the first place?

any sort of explaination would be appreciated. Thanks.

 

Not true!

Of course they only gain minimal hp but hey every add on to the S is minimal.
Oh btw my j's 70rr is a 50lb weight reduction not 10-20. Makes a big impact when combined with other weight reduction efforts

On a 2800 lb car, increasing 15whp (tuned) and losing 50lbs of weight equates to a 9% improvement in hp/weight ratio (2800lbs, 194 whp = 14.4329 lbs/whp, 2750lbs, 209whp = 13.1578lbs/whp)

When I say dual i simply mean 2 mufflers. A true dual usually only comes on non inline motors. (v-6, v8 etc. where there are 2 headers, and essentially 2 separate single exhausts one the car)

The reason singles make more is to due with the velocity of the exhaust gases as I mentioned above. The engine is essentially a big air pump; you want to be able to move as much air through it as possible. The more air you can get out the better.

The reason duals don't make as much power is due to the split; it messes up the exhaust flow and velocity: In addition most duals are decreasing diameter design after the split (i.e. 70mm main piping, 60mm after the split).

A single continuous, non obstructed pipe of optimal size (70mm in the case of the S) will always make more power compared to something with obstructions and varying size tubing.

Also like mentioned duals are heavier and on a car with as little torque as the S, improving the power to weight ratio not only improves acceleration, but also overall handling, weight transfer, and braking.

Hope this all helps.

 

Government noise restrictions. There is NO exhaust that can make more power than the stock exhaust at the same sound level. I suspect that if Honda went with a single-outlet exhaust from the factory it'd have to either a) be so restricted that the car lost a lot of hp, or b) use a single exhaust canister so large it would compromise trunk space. There's a photo somewhere out there of the S2000 prototype sitting in a track garage next to a stack of different exhausts. Honda did exhaustive testing of exhausts (har har) to find one with optimal power and sound qualities.