Chemical X

iTrader: (18)

I’m looking to gather information on the various exhaust pipes on the market and what their main characteristics are. I know some are designed to provide more low-end torque while others provide more top-end RPM. Some are also better on fuel economy than others. But how do you know which one does what? The manufacturer’s descriptions on a lot of the pipes do not offer enough information in my opinion. Therefore, please help me compile a listing of popular pipes and their main characteristics.

Although having information on a specific pipe related to a specific engine is good, like a 2607 to a JL Red Dot for example, I’d like to keep the information more generic. Since many engines are based on the Nova Rossi platform, let’s consider that as the baseline. If we take a basic Nova Rossi engine (.12 or .21 depending on the pipe below), how would it respond by changing from one pipe to another? What happens to the torque, RPM, and fuel economy?

I quickly gathered the following list of pipes online and I know it’s not complete. If you know the characteristics of another pipe that’s not listed, please reply with the information.

1/10
2601
2607
2611
2617
2620
2630
2649
2651
2652


1/8
2013
2015
2018
2033
2052
9853
9863
9886





.

beta bob

iTrader: (2)

Thats the only one i know from personal experience But i would also like to know is how dramatic the differences are if you change the size of the manifold

PMSorber

See in the list (Picco P9 engine)

jakerz

iTrader: (3)

I run all 3 of the pipes I commented on and love them all for different reasons



1/8
2013
2015 - GREAT MID AND TOP END POWER
2018
2033
2052 - TONS OF PUNCH OUT OF THE TURNS AND GREAT MID RANGE, USE A SHORT HEADER TO MAKE-UP
FOR IT'S LACK OF TOP END
9853
9863
9886 - ULTIMATE TOP END POWER PIPE





.[/QUOTE]

Riketsu

iTrader: (34)

http://www.efra.se/pdf/handb07homologation.pdf

afm

First of all you need to Know how pipes work, to understand when and what to use and do with a particular pipe. With this guide you can more or less determine by the pipe design, what it will do...

AFM

All about Pipes

Header
The header's length has a significant impact on performance. The rule of thumb is that a longer header is better for bottom-end power, while a shorter header makes your engine scream on the top end. The longer it is, and it resonates at a lower pitch. The shorter it is, and it resonates at a higher pitch. The idea is to adjust the length until the engine and exhaust system are in sync and “singing” in harmony. You can’t go too far in either direction, so don't be reckless; you'll do more harm than good. The ideal header would also expand outward (conical shape). This subtle expansion, when combined with those of the tuned pipe, helps scavenge, or suck, the exhaust from the engine. The header length is the number you play with when tuning your pipe. A heavier car demands a broader power curve, so a longer header is best. A light car, on the other hand, can be tuned for peak power on a narrow power curve with a shorter header.

Divergent cone
• A sharper angle of the divergent cone makes scavenging more efficient but limits it to a more narrow rpm range.
• A more gradual divergent cone reduces the intensity of the negative wave, but it lasts much longer, so this increases the rpm range.

It's a balancing act of sorts: more performance over a limited rpm range or less performance over a broader rpm range.

Belly
Parallel portion of the pipe, that connects the divergent to the convergent cone. It's length determines the relation between the negative and positive waves.
• A short section is best for developing maximum power at high rpm ranges, but narrower power curve.
• A longer section implies in a broader power curve with less peak horsepower. Its more suited for developing low-rpm power.

Convergent cone
• A sharper angle of the convergent cone limits engine to a more narrow rpm range.
• A more gradual convergent cone increases the rpm range.

Stinger
The convergent cone ends at the stinger ( the pipe portion opened to atmosphere ) which expels the burned gases way out. It works as a pressure bleed valve and controls back-pressure, enhancing the port plugging efforts. If it is too small or too long, you may have engine overheating problems. Too small a stinger causes excessive back pressure into the pipe and raises the pipe and engine temperature.
The ideal stinger diameter should be .58 to .62 times the header diameter, and its length should be 2.86 to 3 times its own diameter.

Stinger diameter affects the top and bottom end.
• Bigger = top end at the sacrifice of low end torque.
• Smaller= low end at the sacrifice of high end revs.
Stinger length affects the top and bottom end.
• Shorter = top end at the sacrifice of low end torque.
• Longer = low end at the sacrifice of high end revs.

The stinger's ideal diameter and length are important to performance, but are limited and governed by most racing sanctioning bodies.

Tuned Pipes Design Examples

Small volume - narrow operating range (peaky)
High volume - lower power (if too big) - broad range
Steep angles - 'peaky' - high power
Shallow angles - broad range - moderate power
Shorter or larger diameter stinger - lower or higher pressures and heat.

How to Pick a Tuned Pipe

• Torque biased. Sharp cone on each end long flat band center, single chamber.
• Low-mid biased. Aggressive divergent cone.
• Mid biased. Moderate divergent cone.
• Mid top end biased. Moderate divergent cone aggressive convergent cone.
• If the engine is a short rod rever you need a torquier pipe to enhance the bottom end as engine will be biased and take over on the top.
• If the engine is a long rod engine you need a rev pipe to help the engine unload on the top.

Pipe length must be considered the same way. The way you intend to use your car in combination with your engine, will dictate the optimal length for the pipe.
The shorter the pipe, the higher the peak horsepower and torque, but the range of the horsepower and torque gets narrower and drops off faster. Also, the shorter the pipe the more fussy your engine will be.
• Shorter=top end at the sacrifice of low end torque.
• Longer=low end at the sacrifice of high end revs.

For optimum performance, the following guide may prove useful.

C) Pipe Length Too Short
• Frequent blowing of glow plugs
• Sand blasted head
• Over heating engine
• Difficult to get 'on the pipe', sensitive needle
• Excessive carbonizing of the head
• Engine sags under load
• 'Harsh' running

D) Pipe Length Too Long
• Very easy on the needles
• Smooth, quiet running
• Prone to burbling, rich running
• No power
• None of above, try shorter and see what happens.

LAM3SAUCE

THANKYOU ALL!!!! especially chemicalX for bringing this subject up! it HELPPED me sooo much!

Ivan Dickson

iTrader: (32)

lots of good infomation....thanks.

Chemical X

iTrader: (18)

Thanks to all who replied, it's very helpful.

AFM,
Your posts provide a wealth of knowledge and are always a good read. Thank you very much.

Victor Vector

iTrader: (9)

Sounds like a day trip to Peru Tom. When shall we schedule it ??

Fantastic reading here.....thanks to you all.

Jacko

Fastforward

iTrader: (5)

http://www.teamorion.com/Products/Nitro+Tuned+Pipes