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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Fri May 27, 2016 5:38 am Post subject: increased cc´s in a Mex. fuel injection 1600i make a sense? |
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Hi guys;
To increase torque a little bit in a Mexican type1 1600i fuel injection engine, it makes sense to increase cc´s and valve size?.... Is really necessary modify the ecu or something else?
Regards.
Last edited by pablovent on Fri Jun 03, 2016 9:54 am; edited 2 times in total |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Fri May 27, 2016 6:51 am Post subject: Re: increased cc´s in a fuel injection type1? |
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There is no modifying the ECU. The hardwired "software".....outside of limiting tunability that you find in modern fully digital aftermarket injection systems......is NOT the size limiting factor here.
The intake manifold is the main limiting factor. The stock intake manifold can comfortably handle a 1776. It will usually require slightly larger injectors.
Be conservative on valve size increase. Go too large and it stalls port velocity with this intake system.....which will cause poor tunability. Add about 2mm to each valve diameter more or less.
You may also need to make a careful tweak to the wiper spring load in the AFM and possibly at worst....a tweak to fuel pressure.
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If you ask around there are some cam choices you can make......but you have to be careful that they are not too radical. The lobe center needs to remain around 108. More duration is better than more lift in these systems as excessive lift causes the vacuum signature to get choppier. That gives the netering flap a hard time.
Nunerous people have done this. Ray |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Fri May 27, 2016 3:43 pm Post subject: Re: increased cc´s in a fuel injection type1? |
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I see is very different from a carbureted engine...... thank you for the advice Ray, can you recommend cam for 1776cc for example? .... RC? ...... |
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mcmscott Samba Member
Joined: March 12, 2010 Posts: 4848 Location: sanger ca
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Posted: Fri May 27, 2016 3:52 pm Post subject: Re: increased cc´s in a fuel injection type1? |
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I used mexican injection(digifant) on my thing engine, 1904cc cb 2280 cam, 40x35.5 los pancheato heads and a merged exhaust with no modifications to the ecu, ran perfect. _________________ There are no stupid questions, only stupid people,
68 Ghia
67 T-1
65 Notch
02 Mexican beetle
74 Thing
15 Long travel rail
07 Nomad
05 f-250 |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Sun May 29, 2016 2:51 pm Post subject: Re: increased cc´s in a fuel injection type1? |
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mcmscott wrote: |
I used mexican injection(digifant) on my thing engine, 1904cc cb 2280 cam, 40x35.5 los pancheato heads and a merged exhaust with no modifications to the ecu, ran perfect. |
Fuel pressure?? .....injectors?
Thanks |
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mcmscott Samba Member
Joined: March 12, 2010 Posts: 4848 Location: sanger ca
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Posted: Mon May 30, 2016 8:36 am Post subject: Re: increased cc´s in a fuel injection type1? |
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Stock fuel pressure, injectors were from a 1.9 liter escort _________________ There are no stupid questions, only stupid people,
68 Ghia
67 T-1
65 Notch
02 Mexican beetle
74 Thing
15 Long travel rail
07 Nomad
05 f-250 |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Mon May 30, 2016 8:58 am Post subject: Re: increased cc´s in a fuel injection type1? |
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As mcmscort noted.....the real key to working with this is careful up sizing of the injectors.
Unlike programmable injection where you can change the fuel curve inputs around and "SOMEWHAT" get a little bit more out of existing injectors when you up-size......with D-Jet, L-Jet and Digifant systems......the fuel curve is the part that is locked down largely....think of it as hardwired instead of software.
A large portion of the "hardwiring" of the curve is the mechanical equipment that the system was built for......so if you upsize.......too far.....and the manifold volume is outrun by too much.....it changes airflow and vacuum response. Valves, cam and exhaust play into this as well.
As I noted.....with the stock beetle L-jet manifold ....and the Digifant is similar.....in general a 1776 is the most comfortable upgrade with the least changes required.
As mcmscott noted.....he offset that by going up a little larger than I would have for a 1776....in valve size......for his 1.9L. The exhaust flowing better than stock helps as well.
And.....the fuel curves are generally still the same when you go up in size on these systems.....but are now lacking in volume for each output the ecu produces. This is why you go up in size for injectors.
You cannot safely just bump the pressure up.....because its already as high as is safely practicable with stock type injectors. The fuel pressure regulators in L-Jet.....and if memory serves.....in Digifant as well......is a vacuum indexed rising rate type regulator. Your fuel pressure is probably about 32 psi at idle and upwards to 42-46 psi on acceleration.
You have no more room to move with fuel pressure alone unless you buy injectors that are rated for constant pressure up to about 52 psi.
So you need to bump your injector size up like mcmscott did. Ray |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Mon May 30, 2016 11:35 am Post subject: Re: increased cc´s in a fuel injection type1? |
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Thanks Ray;
Then go with 1776cc and best or less restrictive exhaust system......But I need mantain the catalytic converter....Only hope temp sensor without temps problems!! |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Mon May 30, 2016 4:07 pm Post subject: Re: increased cc´s in a fuel injection type1? |
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pablovent wrote: |
Thanks Ray;
Then go with 1776cc and best or less restrictive exhaust system......But I need mantain the catalytic converter....Only hope temp sensor without temps problems!! |
Yes....if you must maintain the catalyst. ...then you probably cannot change the rest of the exhaust much either. In that case....I would stay in the 1776 range.
You "should" be able to manage this with the stock injectors. Ray |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Mon May 30, 2016 4:34 pm Post subject: Re: increased cc´s in a fuel injection type1? |
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ok
Last edited by pablovent on Sun Jun 05, 2016 5:51 am; edited 1 time in total |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Sun Jun 05, 2016 5:44 am Post subject: Re: increased cc´s in a fuel injection type1? |
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Thank you Ray;
In the German forums talk about expensive chips, 1804, 1804x, 1825, 1825i, 1800i 70PS Tafel eprom chip, etc....My question is stock 1600i ecu have problems with a simple 1776cc upgrade? |
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bugguy1967 Samba Member
Joined: January 16, 2008 Posts: 4338 Location: Los Angeles, CA 90016
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Posted: Sun Jun 05, 2016 9:46 am Post subject: Re: increased cc´s in a Mex. fuel injection 1600i make a sense? |
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If it's going to be too much of a headache to modify your system to work well with a larger engine, you could always leave the ccs the same and still make torque gains. I'm assuming your engine runs on 87 octane. You could do an intelligent cam swap, and run the compression up as high (and as safely) as possible for the highest octane available there. You could invest time and money into headwork, like unshrouding the intake valves, getting a multiple angle valve job, aligning the manifold ports to the head ports, contouring the guide bosses, blending the seats into the chambers, tightening your deck height and improving your chamber layout. The plug boss always needs some attention. It's usually a big obstruction to the incoming mixture. Depending on what head models you have, a better spark plug may be available too. All these improvements could possibly make a bigger gain than just boring the heads and case for 90.5s and putting it all back together. |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Sun Jun 05, 2016 10:01 am Post subject: Re: increased cc´s in a Mex. fuel injection 1600i make a sense? |
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bugguy1967 wrote: |
If it's going to be too much of a headache to modify your system to work well with a larger engine, you could always leave the ccs the same and still make torque gains. I'm assuming your engine runs on 87 octane. You could do an intelligent cam swap, and run the compression up as high (and as safely) as possible for the highest octane available there. You could invest time and money into headwork, like unshrouding the intake valves, getting a multiple angle valve job, aligning the manifold ports to the head ports, contouring the guide bosses, blending the seats into the chambers, tightening your deck height and improving your chamber layout. The plug boss always needs some attention. It's usually a big obstruction to the incoming mixture. Depending on what head models you have, a better spark plug may be available too. All these improvements could possibly make a bigger gain than just boring the heads and case for 90.5s and putting it all back together. |
thanks, I understand fine, but I want reliable engine, 7.8 CR max, aprox 70hps.
In my country sale 93/95/97 ron fuel, most aircooleds entusiast run with 93 ron fuel.....1600i intakes aparently work fine with 1776cc!.....I supposed 1600i ecu/injectors work fine with 1776cc and 4500 rpms range, but in Germany use special chips, will be really necessary install this chips for 4500 rpm limits or 1776i stock performance?
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Bruce Samba Member
Joined: May 16, 2003 Posts: 17273 Location: Left coast, Canada
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Posted: Sun Jun 05, 2016 11:26 am Post subject: Re: increased cc´s in a fuel injection type1? |
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raygreenwood wrote: |
You may also need to make a careful tweak to the wiper spring load in the AFM and possibly at worst....a tweak to fuel pressure.
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Ray, there is no AFM in the Mex Beetle FI system.
IMO you shouldn't talk about other unrelated FI systems. It creates too much confusion. _________________
overheard at the portland Swap Meet... wrote: |
..... a steering wheel made from a mastadon tusk..... |
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miniman82 Samba Swamp Donkey
Joined: March 22, 2005 Posts: 9515 Location: Southern Maryland
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Posted: Mon Jun 06, 2016 12:48 pm Post subject: Re: increased cc´s in a Mex. fuel injection 1600i make a sense? |
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Right, no D or L jet stuff here, I believe the later systems were digifant were they not? _________________ Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747
Glenn wrote: |
satterley_sr wrote: |
I just wanted to bitch but I'm getting no sympathy. |
Welcome to the Samba. |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Mon Jun 06, 2016 3:05 pm Post subject: Re: increased cc´s in a fuel injection type1? |
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Bruce wrote: |
raygreenwood wrote: |
You may also need to make a careful tweak to the wiper spring load in the AFM and possibly at worst....a tweak to fuel pressure.
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Ray, there is no AFM in the Mex Beetle FI system.
IMO you shouldn't talk about other unrelated FI systems. It creates too much confusion. |
Yep....forgot....thanks for the reminder.....and that.....is most probably why most of the Germans look for a chip upgrade.
If the same intake airflow curve is used...largely compression, cam, stroke, exhaust etc......the injector upsize should be enough. It may take a little playing with orifice sizes on the intake idle air controller. Ray |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Mon Jun 06, 2016 3:17 pm Post subject: Re: increased cc´s in a Mex. fuel injection 1600i make a sense? |
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miniman82 wrote: |
Right, no D or L jet stuff here, I believe the later systems were digifant were they not? |
I noted they were digifant. ...about five posts ago.
And.....it depends on which VERSION of digifant it uses. Digfant 2 uses an air vane/flap....JUST LIKE L-JET...
Saying a system is "digifant".....is not really definitive to anything as there are several vsersions....of each version.
Other versions have used a heated wire or heated resistor. As far as I know...all use wome version of either the dual throttle switches or modern TPS to signal idle and WOT. Some versions also had MAP reference.
I was not sure what the mexi version used. I have worked on only a couple mexi versions.
But back to the subject at hand......without a flap/vane to make inlet air volume tweaks.....the inlet air profile.....needs to remain the same.
Re-chipping would be an easy way to go....as long as you know the configuration that chip is meant for.
Otherwise....what might be a simple volume upgrade that could be handled with a larger injector becomes a REAL fuel map problem.
Ray
EDIT......by the way....we are ALL dancing around a little here on terminology and what each system actually entails. There is fair amount of L-jet knowledge and conversation in the forums....and a fair amount of "Diji-jet" conversation in the vanagkn forums.....but not all that much about what some of the odd versions of Digifant are.
I for one have not had to work on any of them is about 6 years.. ..so I mentally slip as well......but for a small and incomplete piece of history here......the Mexican version is not ACTUALLY. ....classic digifant.
Bear in mind that digifant was originally a proprietary version of improved (debatable) L-jet from VW audi group.....not a Bosch design. It made its debut in the vanagon and was called digijet.
It was an ignition integrated version of L-Jet.....remembering that L-jet went through LE-1, LE-2, LE-3 ,LU with closed lambda loop and LH with hot wire mass air flow metering....all with miniaturization and improvements ranging from programming to knock sensors.
Then there was Digifant 1 and digifant 2.....both of which use VANE TYPE AFM.
The Mexican version ....that is being called digifant.....is actually a version of LH using a hot wire mass air flow unit....but with added features like temp input from the wire and other controls more common to Digifant systems.
Its clear the Mexican unit is a mixture but is mostly LH-jet. Have to read up on it more. |
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pablovent Samba Member
Joined: July 14, 2010 Posts: 900 Location: Chile
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Posted: Mon Jun 06, 2016 4:55 pm Post subject: Re: increased cc´s in a Mex. fuel injection 1600i make a sense? |
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I think a few 200cc´s aprox will not generate or require special chips, sure the stock 1600i ecu will absorb the difference, anyway is always the possibility in the future re-chip the ecu for better curve (only if necessary), perhaps with the time I get the correct data for this modification .... but I have a question, it will not serve equivalent Vw Golf/Rabbit eprom data? |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Mon Jun 06, 2016 6:22 pm Post subject: Re: increased cc´s in a Mex. fuel injection 1600i make a sense? |
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pablovent wrote: |
I think a few 200cc´s aprox will not generate or require special chips, sure the stock 1600i ecu will absorb the difference, anyway is always the possibility in the future re-chip the ecu for better curve (only if necessary), perhaps with the time I get the correct data for this modification .... but I have a question, it will not serve equivalent Vw Golf/Rabbit eprom data? |
Not sure...but with large gaering, cam exhaust nd tire diameter differences......I would bet kts not as close as you think.
If nothing else is changing on your engine other than 200cc....possibly larger valves....and maybe if you find one...a slightly larger TB.....if cam, exhaust and intake manifolds stay the same.....its mostly a volumetric change and not a programmed fuel curve change.
Injectors and ignition timing are the first tuning. Ray |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Mon Jun 06, 2016 6:35 pm Post subject: Re: increased cc´s in a Mex. fuel injection 1600i make a sense? |
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By the way....ALL......the Mexican version of Digifant in fact....is the first of the Digifant family to use strictly MAP signal as the primary mass air control.
Had forgotten that from discussion years ago. Had to look it up. It causes some issues. It took lots of lrogramming to work around those issues to make it smooth....and its fuel maps are not much more sophisticated than the original Digi-jet.....so I have been told.
But the reliability is supposed to be the best of all of the digufant family.
But....there are lots of things you can do to augment MAP signal for tuning.....location, orifice size, delay etc.....before biting the bullet to rechip....if the time comes to tune. Ray |
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