|VOLVO 240 EXHAUST PAGE|
Updated: November 25, 2021 CONTACT
M A I N S
|240 Exhaust Basics
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|Mandrel vs Crushed?
|240 EXHAUST BASICS
|240 NON-TURBO EXHAUST
The 240 exhaust pipe for your non-turbo has changed very little over the years. The B21 engine began in the 240 in 1976 and the similar B230 continued from 1985 to 1993. This exhaust was about 2 inches (51 mm) in diameter and began at the 3-bolt flat flange attachment at the bottom of the exhaust manifold. All of the exhaust variants looked nearly identical and most parts are interchangeable. The catalytic converter was used for all U.S. and Canadian versions. Some versions in other markets had a middle pipe without the catalytic converter.
240 TURBO EXHAUST
The 240 exhaust pipe for your TURBO has also changed very little over the years. The B21FT (B21ET outside the U.S. and Canada) was used from 1981 to 1985. This exhaust was about 2.3 inches (60 mm) in diameter and began at the 3-bolt flange attachment to the back of the turbocharger. All of the exhaust variants looked nearly identical and most parts are interchangeable. The catalytic converter was placed in the front downpipe and was used for all U.S. and Canadian versions. Some versions in other markets had a front downpipe without the catalytic converter.
|240 CUSTOM EXHAUSTS
|For those of you interested in building a custom exhaust for your car, here are some topics you may be interested in.
I have been a hot-rodder for many years and I'll be the fist one to tell you a bigger exhaust will help with engine power and fuel economy. There are a number of articles and videos available which will demonstrate the difference. My personal belief is that a larger exhaust is worth the price for a TURBO or NON-TURBO car, however a non-turbo will pretty much always see less return for the money spent. Plus a larger exhaust is going to be louder inside the car and outside in nearly every case, depending of course on the muffler combination you select.
In the early 1990s my first 240 was a 1983 240 DL. I improved the exhaust on that car by installing a larger 240 Turbo exhaust "back-half" that was inserted after the catalytic converter. This was a factory turbo exhaust, which was about 2.3 inches in diameter. It did noticeably improve performance. These days you can find just such a "cat-back" system for a non-turbo car from places like iPd.
Years ago I had the below 3 inch exhaust built for my 240 Turbo. The downpipe was custom made using mandrel bent tubing. The rest of the exhaust was made by a local exhaust shop using standard 3 inch aluminized tubing, using an economical crush-bending method. A 3 inch catalytic converter was used and one 3 inch muffler was put in back. The catalytic converter was placed in a non-original location (for a turbo car), although that location is the normal location for a non-turbo car. In places where more strict emissions rules apply, this location may not be acceptable.
Reportedly a larger exhaust will help a turbo spool up faster. That's a hard thing to quantify, but what about the horsepower gain with a bigger pipe?
Here's an episode of Engine Masters where they dyno tested a 2.5 versus 3 inch exhaust.
BUILDING A CUSTOM TURBO EXHAUST
The first thing you'll need when you decide on a custom TURBO exhaust will be the downpipe. The most common or original turbo found in a 240 Turbo will have a 3-bolt "cone" shaped flange on the exhaust side as shown below, which is made for a 2.5 inch flange.
If you're going for a larger 3 inch pipe, there are transition flanges available to create a 3 inch downpipe for the above turbo. Usually searching for a "Saab turbo downpipe flange" will find something useful. Sometimes these can only be found in Europe. The first photo below is a 2.5 to 3 inch flange that used to be offered by GenuineSaab.com in the USA. This is one I have used, but it was discontinued. The second photo is a 2.5 to 3 inch flange offered on eBay by Zaustworx in the UK. Also a similar one is offered by KSR in Norway. Most performance parts places like this in Europe speak pretty good English and will usually be happy to help with questions.
It's possible to find ready made 3 inch downpipes also, but often the sources will be outside the USA, like the first image below from Martelius Exaust Systems in Finland.
It's also a good practice to use a flex union somewhere near the engine to help with vibration.
MANDREL BENT versus CRUSH-BENT PIPE
Nearly everyone will tell you for the BEST performance you MUST build a mandrel bent exhaust. Anyone with eyes will agree that smooth consistent bends without any bottlenecks will flow better, but you might be surprised about the real difference. I saw an episode of Engine Masters on Motortrend TV that offered some of the best evidence toward an answer. In Season 6, Episode 83: Mandrel- v. Crunch-Bent Exhaust, a 530 HP naturally aspirated LS V8 was dyno tested with both exhaust types. The difference between MANDREL BENT 2.5 inch exhaust and a standard CRUSH-BENT 2.5 inch exhaust was less than 10 hp at a 530 hp level. So you may consider this if the cost increase for a mandrel bent system is significantly more money.
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