Wednesday, the Queen went for a 300 mile round trip at altitude with long pulls up the mountains. The first leg was with the top off and the return was with the top on and the air conditioner going full blast. It is during the long pulls with the air on that I want more horsepower as it is hard to maintain freeway speed. I’m wondering if Allison headers would be a good solution. Allison claims a peak 10% hp and a 15% torque increase and at higher rpm’s, 15% hp and a 20 % torque increase. Headers seem to be a good solution for just enough HP and torque gain for my driving conditions. Comments will be appreciated.
Headers?
- Thread starter WYOX19
- Start date
Black-Tooth
Tony Natoli
Jim... Mark Allison has the dyno sheets...
to prove his claims... and a history of integrity to back them as well.
Going to a complete Allison exhaust system is a bit of an expense but the gain of 10 - 12 horsepower would put you back to where the A/C was not engaged, and a bit of boost with it turned off as well.
I was driving my 330 hp Vette yesterday and turned on the A/C which made the cockpit comfortable... but must admit I could feel the difference in performance and I was just cruisin'. Must be some sort of a defect we all have, huh! Just can't stand anything that draws on our power... HA!
to prove his claims... and a history of integrity to back them as well.
Going to a complete Allison exhaust system is a bit of an expense but the gain of 10 - 12 horsepower would put you back to where the A/C was not engaged, and a bit of boost with it turned off as well.
I was driving my 330 hp Vette yesterday and turned on the A/C which made the cockpit comfortable... but must admit I could feel the difference in performance and I was just cruisin'. Must be some sort of a defect we all have, huh! Just can't stand anything that draws on our power... HA!
fiatfactory
Steve Cecchele
Read this thread before you buy any sort of header....
http://xwebforums.com/forum/index.php?threads/16109/
Marks data is based on a comparison with a single outlet front pipe and manifold (ie stock for cat cars) ... the benefits would be far less (if any benefit at all) if there was a comparison done to a twin outlet manifold and twin downpipes.
SteveC
http://xwebforums.com/forum/index.php?threads/16109/
Marks data is based on a comparison with a single outlet front pipe and manifold (ie stock for cat cars) ... the benefits would be far less (if any benefit at all) if there was a comparison done to a twin outlet manifold and twin downpipes.
SteveC
Last edited by a moderator:
Thanks Steve. You wrote, "Marks data is based on a comparison with a single outlet front pipe and manifold (ie stock for cat cars) ... the benefits would be far less (if any benefit at all) if there was a comparison done to a twin outlet manifold and twin downpipes."
European X/19 cars are different than my car and I'm not sure about the availability of recommended twin outlet manifold and twin downpipes.
My car is a stock fuel injected 86 with a cat so it seems to me that Mark's headers would be beneficial,so what am I missing?
European X/19 cars are different than my car and I'm not sure about the availability of recommended twin outlet manifold and twin downpipes.
My car is a stock fuel injected 86 with a cat so it seems to me that Mark's headers would be beneficial,so what am I missing?
Dan Sarandrea (Phila)
Waitin' On Parts...
What are you missing? Nothing really.
Many non-North American (NA) posters occasionally forget that USA cars have significantly different exhaust setups as compared to elsewhere due to early implementation of exhaust emission controls and generally stricter standards, at least while the X was in production.
USA X enthusiasts have to take local emission inspection requirements into consideration. Granted these requirements are all over the map, but they are there nontheless.
Not to mention that availability of non-NA/USA exhaust parts is pretty much zero in the USA. Sure there might be an oddball piece here and there from a FIAT enthusiast's parts horde that's most likely got so much rust to make it not worth the effort of price, or the once-in-a-blue-moon offering on a European eBay site for a serviceable part, that you then have to cobble together to match the parts of the exhaust system you don't change.
For a person in the States who wants to order on their credit card brand new, well thought out and well constructed parts from a known supplier and have them show up next week and fit their A/C car properly, there's precious few choices remaining.
Many non-North American (NA) posters occasionally forget that USA cars have significantly different exhaust setups as compared to elsewhere due to early implementation of exhaust emission controls and generally stricter standards, at least while the X was in production.
USA X enthusiasts have to take local emission inspection requirements into consideration. Granted these requirements are all over the map, but they are there nontheless.
Not to mention that availability of non-NA/USA exhaust parts is pretty much zero in the USA. Sure there might be an oddball piece here and there from a FIAT enthusiast's parts horde that's most likely got so much rust to make it not worth the effort of price, or the once-in-a-blue-moon offering on a European eBay site for a serviceable part, that you then have to cobble together to match the parts of the exhaust system you don't change.
For a person in the States who wants to order on their credit card brand new, well thought out and well constructed parts from a known supplier and have them show up next week and fit their A/C car properly, there's precious few choices remaining.
Dr.Jeff
True Classic
Exhaust system design
Without making any comment on the particular after-market exhaust system being discussed here, consider this. The intended use of the vehicle and the engine's power curve should correspond. The distribution and characteristics of power output will be greatly affected by the design of the exhaust system. Simply put, adding 10 more horsepower will not be of any benefit if it is not offered at a usable point for the way the car will be driven. A couple of numbers don't tell the whole story.
Without making any comment on the particular after-market exhaust system being discussed here, consider this. The intended use of the vehicle and the engine's power curve should correspond. The distribution and characteristics of power output will be greatly affected by the design of the exhaust system. Simply put, adding 10 more horsepower will not be of any benefit if it is not offered at a usable point for the way the car will be driven. A couple of numbers don't tell the whole story.
Dr. Jeff, this thread has given me mixed signals and I'm back to being confused. My intended use is for trips longer than 2 hours. Because I live in the inner mountain west, my most challenging driving conditions in the X are long pulls at altitude on freeways such as I-80 and I-15 with posted speed limits of 75 mph. The truth be known, I have to exceed the speed limit to keep the RPM's up for enough torque/HP stay with traffic and traffic moves along at mostly 80 mph. Are headers an option for the above conditions? Should I consider more HP in the form of head and cam work?
Dr.Jeff
True Classic
Modifications
I was not trying to add to the confusion, nor was I making any recommendations as to what you should do. Merely suggesting you do some homework before making a decision, so as to try and achieve the results you desire.
It can be a rather complicated topic but let me just try and simplify it a little. Most engine modifications will change the characteristics of the output from that engine. The distribution of its output can be spread over a narrow or wide band as well as moved up or down in the RPM range, and the "type" of work it best performs can be altered (often stated as torque and horsepower). This applies to all engine systems and modifications made to them: induction type, cam choice, head work, etc, etc. Furthermore, any/all modifications or changes should 'match' the designed characteristics of all the other systems...they all need to work in harmony.
Since we are talking about exhaust systems here, the design of that system can affect these output characteristics...regardless if it is a cast manifold or tube type 'header'. So for example if you purchase a tube header, find one that will fit your requirements; those of your intended use of the car, those of the rest of the engine's systems, and those of the rest of the car's set up (gear ratios, suspension design, etc). Likewise, if you stick with a cast manifold, select one that will also maximize your particular requirements (as Steve C suggested earlier).
You've stated your intended use is street driving (as opposed to track racing). Also you say your engine must already be kept at higher RPM's to maintain pace, to the point of having to exceed speed limit. So it could likely create a worse situation to make any changes that will move the power band further up the RPM range, or even worse, decrease power in the lower/mid range of the RPM band. However,you could then change the drive train gearing to compensate for this, which will also alter other characteristics. And on it goes.
This is why in my last post I said merely looking at the advertised numbers can be misleading. A product may produce 10 more horsepower, but it may produce it at a RPM you can't effectively take advantage of, and it may actually decrease power at a RPM where you need it most.
Furthermore, don't forget to consider how any changes you make may affect other driving characteristics: fuel mileage, noise levels, vibration, around town (stop and go) drive-ability, maintenance, reliability, resell value...to name a few.
The whole subject is much more involved than what I've stated here. Others may be able to express it in better terms than I have. I recall that Steve C has posted a couple of very involved and very informative threads that give a more technical explanation, perhaps you might want to review those. There are lots of excellent books on the subject as well. But if you are like most of us, you would prefer to have someone just tell you what's the best thing to do. Be aware, another person's recommendations may not match your specific requirements.
I was not trying to add to the confusion, nor was I making any recommendations as to what you should do. Merely suggesting you do some homework before making a decision, so as to try and achieve the results you desire.
It can be a rather complicated topic but let me just try and simplify it a little. Most engine modifications will change the characteristics of the output from that engine. The distribution of its output can be spread over a narrow or wide band as well as moved up or down in the RPM range, and the "type" of work it best performs can be altered (often stated as torque and horsepower). This applies to all engine systems and modifications made to them: induction type, cam choice, head work, etc, etc. Furthermore, any/all modifications or changes should 'match' the designed characteristics of all the other systems...they all need to work in harmony.
Since we are talking about exhaust systems here, the design of that system can affect these output characteristics...regardless if it is a cast manifold or tube type 'header'. So for example if you purchase a tube header, find one that will fit your requirements; those of your intended use of the car, those of the rest of the engine's systems, and those of the rest of the car's set up (gear ratios, suspension design, etc). Likewise, if you stick with a cast manifold, select one that will also maximize your particular requirements (as Steve C suggested earlier).
You've stated your intended use is street driving (as opposed to track racing). Also you say your engine must already be kept at higher RPM's to maintain pace, to the point of having to exceed speed limit. So it could likely create a worse situation to make any changes that will move the power band further up the RPM range, or even worse, decrease power in the lower/mid range of the RPM band. However,you could then change the drive train gearing to compensate for this, which will also alter other characteristics. And on it goes.
This is why in my last post I said merely looking at the advertised numbers can be misleading. A product may produce 10 more horsepower, but it may produce it at a RPM you can't effectively take advantage of, and it may actually decrease power at a RPM where you need it most.
Furthermore, don't forget to consider how any changes you make may affect other driving characteristics: fuel mileage, noise levels, vibration, around town (stop and go) drive-ability, maintenance, reliability, resell value...to name a few.
The whole subject is much more involved than what I've stated here. Others may be able to express it in better terms than I have. I recall that Steve C has posted a couple of very involved and very informative threads that give a more technical explanation, perhaps you might want to review those. There are lots of excellent books on the subject as well. But if you are like most of us, you would prefer to have someone just tell you what's the best thing to do. Be aware, another person's recommendations may not match your specific requirements.
spiderrey
spiderrey
Mark just didnt post numbers for his system. He posted the actual print out from the dyno. You should be able to see where the power comes on. Im pretty sure it is a well thought out system with power where its needed. It wasnt designed by some joe blow trying to make a qwuick buck. It was designed and built by someone who worked for a major and well known header company. I have one of his systems on my spider and I love it.
ng_randolph
Bjorn H
fiatfactory
Steve Cecchele
In the USA a twin outlet manifold that will fit the engine and supply a point for fitment of an oxygen sensor is one from a fuel injected Yugo...around the world there are other options, but in the USA the Yugo offers a twin outlet cast manifold that is readily available.
As far as making up a suitable front pipe assembly, any reputable exhaust fabrication shop should be able to handle this request.
The specific issue with the EFI cat muffler is the postioning of the cat converter. If you compare the muffler from carburetted models that also use a catalytic converter, you'll notice the section of pipe that attaches the cat to the muffler is considerably longer on the EFI versions, and therefore positions the cat conv further towards the right (pass side in the USA) side of the car, this creates a problem when trying to fit a suitable twin pipe assembly into an EFI car (ask DomC in germany as he is also encoutering this issue)
You want to have the twin pipes of a resonable length and also have a suitably sized collector and pipe before it enters the cat converter, as NON EFI cars that also use a cat converter use a much shorter inlet pipe to the muffler... it wouldn't be too difficult to modify your existing muffler by shortening the muffler inlet pipe, or use a muffler assembly from a carburetted car that also uses a cat converter. This will move the entire cat converter across to the left (drivers side in the USA) and give sufficient room to fit bends of sufficient radius and size to mate up to the cat with minimal restrictions.
All for a whole lot less cash than any off the shelf "performance" system, and my money would be on it being very similar (read an un noticiable difference) in output and torque....plus it retains a very factory appearance, and quite likely will outlast the aftermarket offering.
SteveC
As far as making up a suitable front pipe assembly, any reputable exhaust fabrication shop should be able to handle this request.
The specific issue with the EFI cat muffler is the postioning of the cat converter. If you compare the muffler from carburetted models that also use a catalytic converter, you'll notice the section of pipe that attaches the cat to the muffler is considerably longer on the EFI versions, and therefore positions the cat conv further towards the right (pass side in the USA) side of the car, this creates a problem when trying to fit a suitable twin pipe assembly into an EFI car (ask DomC in germany as he is also encoutering this issue)
You want to have the twin pipes of a resonable length and also have a suitably sized collector and pipe before it enters the cat converter, as NON EFI cars that also use a cat converter use a much shorter inlet pipe to the muffler... it wouldn't be too difficult to modify your existing muffler by shortening the muffler inlet pipe, or use a muffler assembly from a carburetted car that also uses a cat converter. This will move the entire cat converter across to the left (drivers side in the USA) and give sufficient room to fit bends of sufficient radius and size to mate up to the cat with minimal restrictions.
All for a whole lot less cash than any off the shelf "performance" system, and my money would be on it being very similar (read an un noticiable difference) in output and torque....plus it retains a very factory appearance, and quite likely will outlast the aftermarket offering.
SteveC
If I am interpreting Mark’s dyno data correctly the power comes on between 4.5k and 5.5k rpm. Matt at Midwest Bayless told me that the Queen has a “lazy tach” and when 3.8k rpm is indicated it may be closer to 4k rpm. I’m thinking that the true benefits of Allison headers for my application is when passing another car and not so much when I’m trying to maintain 75 mph on a long grade at 3.8k-4k rpm. I'm wondering if while driving on said long grade at 4k rpm and I feed a little more gas to maintain speed, will the engine respond or will I have to downshift?
Dr.Jeff
True Classic
WYOX19
You are asking the right questions. It is clear that you've got the concept on how to approach it for your specific application. Well done. An informed decision will lead to satisfactory results.
For the benefit of others that seem to have misread my posts, I will repeat myself. My comments are NOT about any particular exhaust system, brand name, or seller...factory, after-market, or otherwise. I am NOT making recommendations on what particular system should or should not be used. And therefore I give NO implications of what is "good" or "bad" to that effect.
You are asking the right questions. It is clear that you've got the concept on how to approach it for your specific application. Well done. An informed decision will lead to satisfactory results.
For the benefit of others that seem to have misread my posts, I will repeat myself. My comments are NOT about any particular exhaust system, brand name, or seller...factory, after-market, or otherwise. I am NOT making recommendations on what particular system should or should not be used. And therefore I give NO implications of what is "good" or "bad" to that effect.
Dan Sarandrea (Phila)
Waitin' On Parts...
Just for fun I did a search on car-part.com, which is a website that has visibility to 130 million car parts in auto junkyards nationwide.
For the entire USA I was able to come up with one hit for a 1990 Yugo GV FI exhaust manifold in a junkyard in Scranton, PA.
Like Rey said, it ain't easy.
For the entire USA I was able to come up with one hit for a 1990 Yugo GV FI exhaust manifold in a junkyard in Scranton, PA.
Like Rey said, it ain't easy.
yugo is 4-2-1 with an o2 bung if its the fuel injected mani.
Jeff Stich
True Classic
But...
Being that the EFI Yugo (GV+ model) was only sold here in the USA 1990-91, & not very many at that, I'd have to strongly disagree with their manifolds being "readily available" here. :no:
Also, while the Yugo manifolds (both EFI & carb'd) are indeed a 4-2 design similar to the Euro or 1974-only-USA X1/9 & 128, the Yugo shares the lower manifold flange tilt-angle with the 128, not the X1/9. This is something that also has to be taken into consideration if/when trying to mix Yugo & X1/9 exhaust pieces together.
Being that the EFI Yugo (GV+ model) was only sold here in the USA 1990-91, & not very many at that, I'd have to strongly disagree with their manifolds being "readily available" here. :no:
Also, while the Yugo manifolds (both EFI & carb'd) are indeed a 4-2 design similar to the Euro or 1974-only-USA X1/9 & 128, the Yugo shares the lower manifold flange tilt-angle with the 128, not the X1/9. This is something that also has to be taken into consideration if/when trying to mix Yugo & X1/9 exhaust pieces together.