Steve Thomas
True Classic
Very neat work.
Riddle Me This - Exhaust headers
- Thread starter KBabcock
- Start date
GregS
ProjectX
Not very loud at all, no louder than my road X. I have driven it on the streets many times without attracting unwanted attention. 4" dia x 26" long, packed with fibreglass and a 2" perforated straight through pipe.
Last edited:
fiatfactory
Steve Cecchele
On Mark's 1600 I recently made a new exhaust system for him... we dynoed the before and after and there was an almost 3kw increase at the wheels, though the first day (on a tuesday) with the middle muffler it was 33 degrees and the second day on the friday it was 42 degrees... thats degrees Celcius BTW, so about 110 on the F scale...and the dyno we used didn't have any sort of temperature correction, just raw figures.
up top is the standard ansa type muffler the engine was originally dynoed with in 2018 and made 109 rear wheel hp, in the middle is a stainless system Mark had made by a local (in sydney) expert but Mark said it felt like it dropped power (which was fitted on the tueday in december dyno run), and bottom is the 2 1/4 inch mandrel bend, 2 1/4 internal tube "triple flow" muffler and 2 1/4 tailpipe exhaust system I welded together for him and was fitted for the Friday dyno run.
all three systems fit onto the same ansa copy 4/2 extractors, all exit in the same place in the bodywork, all mount to the same standard factory exhaust mounts.
The car is noticeably faster with the new exhaust system, and late next week we are going back to the original dyno we used back in 2018 to get some comparative figures... the same basic engine combo, just now with a better muffler, 36mm chokes up from 34mm chokes in the 40mm DCNF's and different (short) auxiliary venturis and slightly larger main jets, we want to see if it's topped 109wheel hp / 120 lb/ft torque from these couple of changes.
SteveC
up top is the standard ansa type muffler the engine was originally dynoed with in 2018 and made 109 rear wheel hp, in the middle is a stainless system Mark had made by a local (in sydney) expert but Mark said it felt like it dropped power (which was fitted on the tueday in december dyno run), and bottom is the 2 1/4 inch mandrel bend, 2 1/4 internal tube "triple flow" muffler and 2 1/4 tailpipe exhaust system I welded together for him and was fitted for the Friday dyno run.
all three systems fit onto the same ansa copy 4/2 extractors, all exit in the same place in the bodywork, all mount to the same standard factory exhaust mounts.
The car is noticeably faster with the new exhaust system, and late next week we are going back to the original dyno we used back in 2018 to get some comparative figures... the same basic engine combo, just now with a better muffler, 36mm chokes up from 34mm chokes in the 40mm DCNF's and different (short) auxiliary venturis and slightly larger main jets, we want to see if it's topped 109wheel hp / 120 lb/ft torque from these couple of changes.
SteveC
Dr.Jeff
True Classic
I have considered this approach of modifying a commonly available 4:1 header into a 4:2:1 design but haven't tried it. I wasn't sure how the relative lengths of the three segments would work out. However for most of us it is certainly a much better starting point than making a complete header from scratch. Great work and glad to hear it works well.
The main reasons I haven't tried that approach are three fold. 1) I was able to acquire the upper half of a original ANSA system in excellent condition and will fabricate the rest. 2) I also acquired a factory Euro spec 4:2 cast iron manifold in excellent condition and can make a system for it. 3) I decided to experiment with the turbo system from a UT and acquired the turbo and matching manifold for that. So I already have too many potential exhaust system options and only need one at this point.
But I still think modifying a off the shelf 4:1 into a 4:2:1 is a excellent way to go.
Steve Thomas
True Classic
Yeah, dead giveaway on that SS system - enormous fat bit long after it matters but can be seen from the back of the car... Also crude 2/1 merge. The other two systems have decent merge.
KBabcock
True Classic
Here is an interesting way to build custom headers. Once you piece them together you feed data from the parts into a program that tells you what pipes you will need and where to cut them. Only issue is it is pricy for a single header.
icengineworks Header Modeling Kits - Hot Rod Engine Tech
Header modeling kits from icengineworks help car builders and professional shops design and pre-fit full-size 3D model headers that can be easily reconfigured until a perfect fit is realized. This allows engine builders to construct the best possible header based on proven mathematical...
hotrodenginetech.com
jimmyx
True Classic
Legos for gearheads.......