Dual Carb Ideas
- Thread starter Bradders
- Start date
Ulix
True Classic
Hi James,
there is a whole lot of great info on upgrading these engines in this forum. You should spend some time reading it.
Some quick thoughts:
- DCNFs are the "best" choice
- DCNFs alone will not make your car faster with an otherwise stock motor
- Bolting parts to the outside of the engine gives mediocre results at high costs. Build the engine from the inside out and not step by step.
- In upgrading your engine, dual carbs can come way at the back of your list. Exhaust manifold, CR, cam, head work should all come first IMO - you can build quite a hot engine with a 34 DMTR.
there is a whole lot of great info on upgrading these engines in this forum. You should spend some time reading it.
Some quick thoughts:
- DCNFs are the "best" choice
- DCNFs alone will not make your car faster with an otherwise stock motor
- Bolting parts to the outside of the engine gives mediocre results at high costs. Build the engine from the inside out and not step by step.
- In upgrading your engine, dual carbs can come way at the back of your list. Exhaust manifold, CR, cam, head work should all come first IMO - you can build quite a hot engine with a 34 DMTR.
carl
True Classic
carbs
I'm not going to argue with Ulix's basic premise but dual carbs do have some interesting aspects on an otherwise stock motor. They give instant throttle response over a single carb and certainly give the impression of more power. They also make a glorious sound that makes you not care whether the engine is actually more powerful.
Dual carbs can be a pain sometimes to keep running right, this being mostly keeping a nice idle.
DCNFs are the standard dual carbs for Xs. For IDFs you need a specific manifold different than the DCNF manifold and are probably very hard to find (I have a dual IDF manifold for a 128 but it's eventually going on my wagon.). DCOE sidedraft carbs are another option but I believe you have to cut into the trunk for filter clearance.
All my 124 spiders wear dual IDFs and my 128 sedan had dual IDFs.
carl
I'm not going to argue with Ulix's basic premise but dual carbs do have some interesting aspects on an otherwise stock motor. They give instant throttle response over a single carb and certainly give the impression of more power. They also make a glorious sound that makes you not care whether the engine is actually more powerful.
Dual carbs can be a pain sometimes to keep running right, this being mostly keeping a nice idle.
DCNFs are the standard dual carbs for Xs. For IDFs you need a specific manifold different than the DCNF manifold and are probably very hard to find (I have a dual IDF manifold for a 128 but it's eventually going on my wagon.). DCOE sidedraft carbs are another option but I believe you have to cut into the trunk for filter clearance.
All my 124 spiders wear dual IDFs and my 128 sedan had dual IDFs.
carl
Black-Tooth
Tony Natoli
I agree wholeheartedly with everything Ulix...
and Carl said, and would like to add...
1. I dunno if you have a chin spoiler up front or not. If not, installing one is a must.
2. I see your heater valve lever is broken... meaning a rusted cable or stuck valve or both. I would fix this next.
3. Philosophically speaking... adding more air and fuel and not addressing the exhaust, cam and valves is not taking FULL advantage of the carb's potential. Leaving the bottom end stock and installing bigger valves, headers, a cam and THEN the carbs will give you a really fun little car.
and Carl said, and would like to add...
1. I dunno if you have a chin spoiler up front or not. If not, installing one is a must.
2. I see your heater valve lever is broken... meaning a rusted cable or stuck valve or both. I would fix this next.
3. Philosophically speaking... adding more air and fuel and not addressing the exhaust, cam and valves is not taking FULL advantage of the carb's potential. Leaving the bottom end stock and installing bigger valves, headers, a cam and THEN the carbs will give you a really fun little car.
Thanks for the advice
I'm going to strip down the entire car and repair everything whilst I'm at it, probably including a respray. I just thought I'd take advantage of having the engine out the car to modify it a bit.
Are there any recommended places to get uprated engine internals for the 1500?
Thanks again
James
I'm going to strip down the entire car and repair everything whilst I'm at it, probably including a respray. I just thought I'd take advantage of having the engine out the car to modify it a bit.
Are there any recommended places to get uprated engine internals for the 1500?
Thanks again
James
rjplenter
True Classic
Look here for performance packages
James, have a look here:
http://xwebforums.com/forum/index.php?threads/26275/
Steve is a top bloke and really knows how to make these SOHC engines get up and go.
Cheers,
Rob
James, have a look here:
http://xwebforums.com/forum/index.php?threads/26275/
Steve is a top bloke and really knows how to make these SOHC engines get up and go.
Cheers,
Rob
Last edited by a moderator:
fiatfactory
Steve Cecchele
That thread is in FS&W 'cos it's more about selling some of the bits and pieces I have....
This thread is more about information ...
http://xwebforums.com/forum/index.php?threads/22546/
best viewed if you are logged in, and in 'Hybrid' thread display mode, so it displays correctly in 'chapter' order...
you might find it informative.
SteveC
This thread is more about information ...
http://xwebforums.com/forum/index.php?threads/22546/
best viewed if you are logged in, and in 'Hybrid' thread display mode, so it displays correctly in 'chapter' order...
you might find it informative.
SteveC
Last edited by a moderator:
Rooster
piccole ma cattive
My advice.
A while ago I started a thread detailing a budget engine build. (here: http://xwebforums.com/forum/index.php?threads/5138/). Whilst my budget was blown out considerably, the premise stayed the same. A must for the 1500 is a CR boost and a better flowing head. This (un)fortunately calls for a better cam and a decked head or higher compression pistons. While not absolutely necessary, H-beam conn rods will help later down the line when you want even more power. My initial build was this:
Completely serviced 1500 block (bores checked at 87mm). new frost plugs. Crank was balanced with fly wheel and pinned. Crank bearing and conn bearing journals were polished. Lightened flywheel (this will help with quicker RPM). Cylinder head was decked, 3 angle grind, ported and polished. A much hotter cam (mfg unknown, race cam). Dual DCNF40's and manifold. Also needed is a header. There are 2 styled, long tube and short. Both have different characteristics, benefits and drawbacks. But you'll need one, the stock unit is horrible. Also you have to thing about your fuel delivery. The stock pump (carbed) will work, but feeding 2 DCNF's it will lag a little. I went with a Carter unit that will put 5psi thru a garden hose all day.
Thats about it in a nutshell. That was last years build, it has since changed drastically. Some for the better, some not so much. I never dyno'd the engine but the seat o' the pants dyno suggested about 115-120hp at the wheels. That's enough to spin 10" wide race slicks from a stand still.
A while ago I started a thread detailing a budget engine build. (here: http://xwebforums.com/forum/index.php?threads/5138/). Whilst my budget was blown out considerably, the premise stayed the same. A must for the 1500 is a CR boost and a better flowing head. This (un)fortunately calls for a better cam and a decked head or higher compression pistons. While not absolutely necessary, H-beam conn rods will help later down the line when you want even more power. My initial build was this:
Completely serviced 1500 block (bores checked at 87mm). new frost plugs. Crank was balanced with fly wheel and pinned. Crank bearing and conn bearing journals were polished. Lightened flywheel (this will help with quicker RPM). Cylinder head was decked, 3 angle grind, ported and polished. A much hotter cam (mfg unknown, race cam). Dual DCNF40's and manifold. Also needed is a header. There are 2 styled, long tube and short. Both have different characteristics, benefits and drawbacks. But you'll need one, the stock unit is horrible. Also you have to thing about your fuel delivery. The stock pump (carbed) will work, but feeding 2 DCNF's it will lag a little. I went with a Carter unit that will put 5psi thru a garden hose all day.
Thats about it in a nutshell. That was last years build, it has since changed drastically. Some for the better, some not so much. I never dyno'd the engine but the seat o' the pants dyno suggested about 115-120hp at the wheels. That's enough to spin 10" wide race slicks from a stand still.
Last edited by a moderator:
Rooster
piccole ma cattive
Your best option for budget is a complete Uno Turbo MkI engine swap. It bolts right in and stock, it puts out 105hp. With bump in boost, it'll hit 125+. You must have a few in GB kicking around.
Rooster
piccole ma cattive
I have both an Uno powered X and a dual carb Race X. While the dual carbs offer alot of raw hp, they are a pain to adjust and keep adjusted. With the Uno (uno bits added to a 1500 that is) at 7psi boost, the pull was amazing. Interestingly enough, the stock ign unit of the 1500 FI works fine with the uno set up.
Since the bee is stripped and awaiting a repaint, the real Uno block will go into this, along with the twin intercoolers from a modern Abarth. With all that cooling, I'll probably upgrade to a TD04 turbo.
Just food for thought. Good luck, you should be happy with either option!
Since the bee is stripped and awaiting a repaint, the real Uno block will go into this, along with the twin intercoolers from a modern Abarth. With all that cooling, I'll probably upgrade to a TD04 turbo.
Just food for thought. Good luck, you should be happy with either option!
Ulix
True Classic
Oh wait, you have a euro model?
That changes things!
The exh. manifold and exhaust is not horrible on your car.
The CR is not way low.
The cam is actually quite good.
Good news!
But here is the bad news:
You have a pretty good motor in stock form.
Making it fast is much harder (€€€) than the US motor.
My advice: if budget is low, make the stock engine run as well as it can by servicing it. You may find some good power here.
Making the engine much faster than a well running stock euro 1500 will be a bunch of money.
That changes things!
The exh. manifold and exhaust is not horrible on your car.
The CR is not way low.
The cam is actually quite good.
Good news!
But here is the bad news:
You have a pretty good motor in stock form.
Making it fast is much harder (€€€) than the US motor.
My advice: if budget is low, make the stock engine run as well as it can by servicing it. You may find some good power here.
Making the engine much faster than a well running stock euro 1500 will be a bunch of money.
rachaeljf
True Classic
If you want to stay with carbs, increased capacity would be good. You can go to 1581cc reasonably easily out of the Fiat parts bin and even up to 1870cc with aftermarket pistons and rods, a late sohc block and Stilo/Brava 1.6 crankshaft.
Turbo options are getting more difficult as the most suitable engines are getting rare now. You have a choice of Uno Turbo 1300 - easiest, almost a straight swap but very rare and people have got wise, and UT 1400. Then you have the Punto GT (1400cc) engine, which is a development of the UT 1400 engine.
Turbo options are getting more difficult as the most suitable engines are getting rare now. You have a choice of Uno Turbo 1300 - easiest, almost a straight swap but very rare and people have got wise, and UT 1400. Then you have the Punto GT (1400cc) engine, which is a development of the UT 1400 engine.
This is something I don't quite get, how do you know which parts fit these engines? I'm used to the MX5 Mk2 1.8 lump which seems to have no similar parts.
Thanks
James