Very well could be. It was in my X1/9 pictures folder where I save pictures from the web that are relevant to projects I'm working on. I'm running the stock 1500FI cat. My MR2 is de-catted and the smell is noxious while sitting and idling - kind of convinced me it's not really worth it with the X. Actually looking to put a cat back on the MR2 . . .
Very well could be. It was in my X1/9 pictures folder where I save pictures from the web that are relevant to projects I'm working on. I'm running the stock 1500FI cat. My MR2 is de-catted and the smell is noxious while sitting and idling - kind of convinced me it's not really worth it with the X. Actually looking to put a cat back on the MR2 . . .
JNewm
True Classic
Hmm... I'm currently running an all-factory exhaust system (1500 FI) except with the cat removed and a straight pipe welded in its place. I'd been planning at some point to replace it with the MWB header + factory muffler system. Any thoughts on whether this by itself would yield a performance increase vs. a catless stock system? Put another way, is the factory US manifold + downpipe the restriction, or is it the muffler? Or is it both, such that modifying one or the other in isolation is a waste of time/$$?
Dr.Jeff
True Classic
You asked for thoughts, there are only mine....
Here is where the points brought up by others come into play. First let's keep things in perspective; ANY exhaust modification on the X (particularly a stock one) will yield a minimal performance increase in the general scope of things. Even a 10% increase (which will likely never be reached) is only a couple of HP/torque, so not really significant to be honest. I think there is a lot of psychology at play, perceiving more improvement than reality would demonstrate on a dyno. But I guess any improvement is a good thing, so it may come down to your budget. The more you can change the system from stock to "performance", the more you are likely to get some increase. However also keep in mind another point that was brought up. Are we talking about a track car where it will be driven at constant redline where most of the improvement is found? Or is it a street car where some loss of low/mid range torque may result in an actual loss of drivability? So it might be fine to retain a stock system for most owners. For those that like to modify things, then realize what you will actually get (better or worse) for the money you spend, and enjoy modding your X - I know I certainly do.
MikeHynes
True Classic
Here's a pic of a (dirty) Ansa muffler that fits the stock 1300 dual outlet exhaust manifold. Notice the brackets specific to the early mufflers. These can be modified to fit on a 1500 (see pic of X below).
Here's the same style muffler installed on a '74 with a 1500.
Ansa offered a version of the muffler that integrated into one of their four into two into one headers.
(BTW - Ansa also offered the muffler with one megaphone style outlet - that exited on the left hand (driver's) side.)
Good luck finding one!
Here's the same style muffler installed on a '74 with a 1500.
Ansa offered a version of the muffler that integrated into one of their four into two into one headers.
(BTW - Ansa also offered the muffler with one megaphone style outlet - that exited on the left hand (driver's) side.)
Good luck finding one!
fiatfactory
Steve Cecchele
I can tell you've missed the point completely by your focus on the exhaust tips. The issue with the stock system is the 4 into 1 manifold and the round the houses front pipe - THAT is the primary restriction - if you were to remove the muffler completely but leave the stock manifold / front pipe and a test pipe (or cat)in place it would be - almost absolutely unlikely - that any improvement would be seen, let alone 5%... simply because you have not removed the primary restriction.
The vehicle I fitted the quad outlet ansa to, yes was making considerably more than stock power (remember a stock euro 1500 carb is 85hp at the flywheel, that is a mid 60's number at the wheels) and the quad tips became that primary restriction at that level of exhaust flow, and removing them was one of a number of smaller steps that showed a nett gain (each time) on the dyno at the rollers.
As development on that car continued I replaced the ansa muffler with a much larger internal pipe sized muffler (2.25 inch) and we went back to the dyno and the car hit it's peak of 118hp at the wheels, so with tuning we went from 97 at the wheel to 118. The second dyno day (which as just two pulls anyway) was just to confirm that my exhaust was an actual improvement (as I'd told the customer if it went down he could have the work for free.) I've seen people (An Alfa GTV6 comes to mind) that spent a ton of time and money working out what they thought was the ulimate exhaust for a particular car, only to have a nett loss on the dyno.
The 1603 X19 I built had a new muffler recently, I had told the customer I thought this was the primary restriction (and I think the dyno curve shows it) so he went to some exhaust specialist that told him "yeah I've done lots of these, I have a good muffler that I use" and the thing drpped power... sure that muffler might be a good one he's used lots - on standard engines - but this one is making about 140 at the crankshaft, like a 75% increase over stock so the "exhaust specialists" muffler was a very poor choice in this case
SteveC
The vehicle I fitted the quad outlet ansa to, yes was making considerably more than stock power (remember a stock euro 1500 carb is 85hp at the flywheel, that is a mid 60's number at the wheels) and the quad tips became that primary restriction at that level of exhaust flow, and removing them was one of a number of smaller steps that showed a nett gain (each time) on the dyno at the rollers.
As development on that car continued I replaced the ansa muffler with a much larger internal pipe sized muffler (2.25 inch) and we went back to the dyno and the car hit it's peak of 118hp at the wheels, so with tuning we went from 97 at the wheel to 118. The second dyno day (which as just two pulls anyway) was just to confirm that my exhaust was an actual improvement (as I'd told the customer if it went down he could have the work for free.) I've seen people (An Alfa GTV6 comes to mind) that spent a ton of time and money working out what they thought was the ulimate exhaust for a particular car, only to have a nett loss on the dyno.
The 1603 X19 I built had a new muffler recently, I had told the customer I thought this was the primary restriction (and I think the dyno curve shows it) so he went to some exhaust specialist that told him "yeah I've done lots of these, I have a good muffler that I use" and the thing drpped power... sure that muffler might be a good one he's used lots - on standard engines - but this one is making about 140 at the crankshaft, like a 75% increase over stock so the "exhaust specialists" muffler was a very poor choice in this case
SteveC
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Dr.Jeff
True Classic
Nothing was missed, we are just discussing a different aspect of his exhaust system build at this point, the exiting tips. Perhaps you missed all the discussion about making a custom system, using a aftermarket muffler and making all the pipes to match? Nothing in there about using factory anything.
But the general consensus all around seems to be eliminate the stock components. Beyond that anything goes as far building a system from scratch. So the general rules for good design can still be applied.
But the general consensus all around seems to be eliminate the stock components. Beyond that anything goes as far building a system from scratch. So the general rules for good design can still be applied.
Regan Burba
True Classic
Curious, if one were to use a cast 4-2 manifold and stock muffler what would be the best option for a custom down pipe to the muffler or cat delete pipe? Should it be two pipes into one or maybe a larger single pipe if that would even work? I ask about the single pipe because that could work with a Yugo manifold by adding 02 sensor in similar area as stock down pipe.
fiatfactory
Steve Cecchele
well actually we are discussing using many of the "stock" components
The Original Poster mentioned he already had an early cast 4/2 manifold and yugo front pipe in his plans and had purchased same.
While I agree with some of the "ultimate" exhaust ideas put forward, but the design criteria here include the use of at least the cast manifold and perhaps the entire stock muffler support springing system (but not necessarly the muffler as the owner wants quad tips)
His referernce point for his desire for that exact system is what he has seen/heard on other cars / 60/70 Italian sprts cars etc, I get that.
I was simply pointing out that that EXACT example is particularly crap from a performance perspective for a paticular reason and I had personal experience with exhausts and dyno time to have a working knowledge what works and what doesn't.
Adapting somethng Camaro and fitting hs own choice of dual tips to get the quad look he wants with the exits where he wants etc etc is why making any sort of complete "run" of any performance exhaust made is too hard for most vendors, as there is so much personal taste involved, not just what works best, and the permutations would be almost endless needed to keep everyone happy.
What I'm talking about is what actually, truely, absolutely and undoubtedly makes a vast improvement in performance over the singe outlet 4 into 1 cast manifold, and that is to replace it and the front pipe with a 4 into 2... it yeilds about 8% nett, proven over and over again, pretty much regardless of what muffler you hang off the back of it. It is the single biggest performance improvement you can make from the factory ats bin. Installing a euro cam doesnt nett as much, it netts more when the two are combined tho....
as for the secondary length, yes there are some lengths that will "work" better but what matters is what packages best, and to a lot of people what is easiest.
We get to use more standard Fiat parts that are readily available and IMO quite reasonably priced and light enough to ship international cheap as well... the front pipe... at least as a basis for a front pipe that packsges into the space.
next Design criteria that is often overlooked is system total length and system total volume... thats the drone maker / killer and part of the reson for the size I use being 2.25, to get a large enough total volume in the muffler otherwise they are mostly too small and restrictive inside, especially when you make 75% more than the stock output, but at much lower power output (I guess at around 90/95 real hp at the crank) the large stainless muffler works just fine as well.
SteveC
Dr.Jeff
True Classic
No, those parts are not "stock original spec" on a US spec X1/9, as his car is. But I think we are pretty much on the same page. So semantics aside, there is room for improvement using the upgraded (Fiat, but non stock) parts he has and making the rest custom - including the piping and muffler.
79X19
True Classic
Thanks everyone for the helpful feedback. I have a good idea of how I will proceed. As always I learned a ton from your responses.
Mark Allison might still be making headers and exhaust. If so, he might be able to do the quad tips for you.
And here's his complete header/exhaust setup.
Allison site:
And here's his complete header/exhaust setup.
Allison site:
X 1/9 Header with Catalyst and Hushpower Muffler (Ceramic Coated and Polished)
X 1/9 Header with Catalyst and Hushpower Muffler (Ceramic Coated and Polished)
allisonsautomotive.com
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Steve, always appreciate your impressive knowledge.
I have a U.S. 86 X. It's still mostly stock and runs well. Have to pass smog inspection here in Cali.
I think I can get a little more enjoyable street performance with a "warm" Euro spec cam and a 4:2 exhaust manifold and front pipe as you describe above.
I would either keep the stock cat and muffler for now, or get a new cat and muffler with a bigger ~2.25" ID.
I would love to do the Allison whole system (with cat) (see post above), but it's a little pricey for me right now @ ~$1250, assuming he's still making them.
So maybe I can do what you're describing.
May I ask you:
1) Which 4:2 exhaust manifold should I be looking for?
2) Which front pipe works best? Is it 2:1 in design?
(The selection is a bit confusing and I don't want to source the wrong parts overseas.)
3) Would I have to do some fabricating from the new front pipe to the stock U.S. exhaust? I'm guessing it's probably not a direct fit.
4) And, just curious, what do you think of the Allison exhaust design as he describes it in the above video?
Thanks!
*** UPDATE: I think I found the part number for the Euro 1500 4:2 exhaust manifold. 4392487. Is that the one?
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