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Old bus, good bus, needs new engine. Has FI, like FI, don't want to fiddle with dual carb linkage. Looking at Jake Raby's big bus engine, but his site says stock FI does not deliver enough power. Someone suggested using stock bits, bigger bosch injectors, and an after market ECU, such as Perfect Power. Anyone done this? Reasonably handy here, can figure out remaping, but don't want to fabricate bits. Want to go with bolt on modifications.

Also curious -- dia of stock throttle body.
Specs on stock injectors.

Had the idea that it might work to use the stock ECU and simply replace the stock FI injectors with some compatible Bosche injectors with a higher flow rate, say 20% greater flow rate than stock, to accomodate larger displacement of the larger engine, would this work? Or does this result in poor mix (too rich/too lean or combination under various loads).

Hi ,
You need after market ECU .// Haltech, or if you want the best. Autronic is the way to go.
Ben

Derek, there are few injectors if any, that are compatable that actually flow at a higher rate. Most do not work as well because they are of the wrong resistance range...and change the injection duration. Injection volume is a function of open time versus pressure at a given basic flow rate. For what you need, simply raising fuel pressure by about 2 psi..will give you a lot of fuel volume across the board. I would exhaust some of the possibilities of the stock injection before I went to aftermarket. I picked up 20 + hp over stock just with a cam change and a lot of little tuning changes and I'm not done with the stock injection yet. Aftermarket injection is nice, but on a close to stock size street motor ...in my opinion...will probably not be a necessary expense. The Hp potential in stock injection is there ..you just need to exploit it. I don't know of any after market injection that simply installed on a stock motor has given any better than the 102 HP I'm currently getting with stock injection. What aftermarket does do...is allow easier adjsutment to larger motors...and it is new...so if there are basic system parts for your s that are worn out and you just can't replace...by all means go to aftermarket. I'm also not impressed with a lot of the after market systems lack of self adjustability (limited sensor net)...which translates to less drivability for a daily street driver..but thats just my opinion. Ask around to some who use the system for this application. Ray

Thanks Ray. I've seen your posts, I think you know your stuff. Now where to I track down a compatible pressure regulator that will increase the PSI of the system?

I'm running a bus, so torque is pretty important, I don't want to lose much torque, and Jake Raby, who seems to have everyone's sunshine around this board, keeps the stock cam grind on his souped up bus specific engine. He moves the crank up to 78 mm to get 2165cc, and I expect the thing spins faster than stock with all the balancing and counter balance.

I saw some mention of a book on tweaking bosche FI systems, and seems like that's a good place to start on this stuff. The idea is to avoid spending $3,000.00 on FI stuff, I need to put that money to the new engine!

Depending on what you are after in hp...you may very well end up with an after market system. I just know that 100+ Hp is easily possible with stock injection...for very little money. But tuning must be done methodically. One thing to note about going to larger injectors or higher fuel pressures. These will be some of the last modifications you will do. Both of them give you more fuel across the board...when you may only need it on acceleration. I would move to a higher pressure rising rate regulator (L-type) before I changed the injector. I would exhaust the system adjustments before I did either. The key is getting the system to give you more injection open duration...and on throttle injection duration...with the existing injector. Large cam changes cam produce a vacume profile that actually leans you out at the wrong time ...with a rising rate regulator. The rising rate regulator cannot be used with late D-type as delivered. It already has two seperate enrichment systems...and the rising rate (vacume controlled) regulator of the L-type will kick in while the other two are working...over-enriching you. On D-type a rising rate regulator can only be installed and used...if you go to a very early non-diaphram type manifold pressure sensor (type 3) with a type 3 ECU...all of this is easy to do, they plug right up...and use the rising rate regulator in place of the diaphram and manifold pressure switch of the early models. Calibration of this is a long process...lots of driving, stopping adjusting. It works well for larger than stock motors that need a lot more enrichment fuel. Not great for a daily driver. The rising rate fuel pressure regulators on nissan 280Z and 280zx and 200sx...old and new in the junkyard work very well. Their pressure runs from about 30 psi to about 38..which is about the top end limit for these injectors .They also have standard fuel line nipples There is a Bosch rising rate regulator used...I think... on a mercedes or renault..that is still readily available...but has CIS style pressure connections...easy to get around with metric unions and tubing...it has adjustable vacume sensitivity also! I will drop the part # in today or tommorrow if I can get home for lunch. Lots of possibilities for tuning. The throttle response changes will be excellent. Most people tell me that wether they get the expected horsepower or not from this kind of tuning work,...that the throttle response and smoothness is nicely uncharacteristic of what has been expected in the past out of stock L and D type. Ray

The bigger displacement will be a large help. The grind #73 would actually be a pretty good cam for this vehicle. It has good breathing characteristic and already has the same basic valve timing as the L-type stock cam...which was the same as D-type. There was one main injection cam...with a minor change in the early 411 years...most all on this continent were the later cams. The carb cam was the one that was different. The FI cams would run well with carbs...but not vica-versa . Stock compression on the 1.7 FI for example was 8.2:1. This was pretty good and gave no problems. 8.0:1 or a little better will be nothing but good for your engine. With the size of engine you are building....you may very well need a little better fuel than stock injector rate will offer. One thing that will help...it may sound like overkill...is to use two fuel pumps and two fuel pressure regulators...one for each pair of cylinders, with no connection of the left and right fuel rings...except a spur line to the cold start valve. There is a problem on D and L (D more than L) with the line pressure dropping when you drop the throttle...and taking a split second to come back up...causes pinging off the line. It helps when the regulator doesn't have to contend with such a large fuel ring and four injectors sucking fuel all at one time. Both regulators should have their vacume coming from a common "TEE". If enrichment at high rpm and full advance becomes a problem, use a fixed pressure regulator from a D-type to feed the fuel to the cold start injector ...so you can throttle it back. Hook the cold start injectors ground...tandem with its original ground that goes to the thermo time switch so that funcyion will still work when needed... the other end into the micro switch that goes onto the throttle body (after you install one)...this will kick the cold start injector on...at reduced pressure, when you put full stroke on the throttle....extra enrichment. It will probably negate having to use bigger injectors, and just leave you with finding a rising rate regulator with only a couple of pounds of extra pressure. There are sveral aftermarket companies that make adjustable rising rate regulators for digifant and motronic. They are not cheap...but are beutifully made and bolt right up. Call Neuspeed...I think they will know. Ray

Thanks Ray

FYI, the system on the bus is the L-Jet, on a 2.0 L stock engine, its the system without the microswitch on the throttle body, and without the throttle switch on the plennum -- the 1976/1977 set-up, I believe.

My thinking is to keep the crank at 71mm but counterbalanced, upgrade to 96mm piston/cylinders to bring cc to 2050 and move compression from stock 7.3 to 8.0. Move to web cam, near stock grind, I'll probably need advice on grind, but that's for later. I've seen some info on 74 mm cranks, and will look into that too, don't want to have to get into modifications for clearance.

Seems like general knowledge on the bosche L-jet applications in different vehicles sure is of assistance in the tinkering. Time to order some manuals and dig into the reading.

Idea is to get better than stock 70 hp in an engine that's not going to cost a fortune and will have good economy and life span. Its running a bus, not a show car. I just want to get up a few hills in my mountainous part of the world.

Ray, thanks for the information, I'm starting to sort this stuff out.

FI is a system of delivering a "squirt" of fuel into the intake manifold along with a rush of air, and a bunch of stuff to determine the size of the squirt.

I understand that the size of the squirt is determined by the computer based on variables of air flow, and temperature. The amount of air is determined by the throttle body, and the flow of the intake system, working outward from the intake valves, manifold, plenun (if any) TB and airfilter.

Stock system has a head temperature sensor, an airflow sensor, and intake air sensors.

Increase the displacement of the engine, and you get increased air, but not increased squirt on the stock system.

You suggest that increasing the pressure behind the system, can increase the amount of fuel delivered, as the system is going to still think its at stock pressure, but its getting pressure boost.

What is the pressure set by the stock pressure regulator?

I saw a 280zx in a wrecker, and looks like the pressure regulator would bolt in easily. What are its pressure characteristics?

I also noticed an adjustable regulator on CB performance:
http://www.cbperformance.com/catalog.asp?ProductID=315

Is there a way to determine if the air/fuel ratio is over or under-rich? Exhaust gas analysis? Is there a cheap device to purchase that does this for the home mechanic?

Stock FI for Bus, is it regarded as providing optimal mix, lean or rich?

If I increase engine displacement, then does enough air flow into system through stock TB? How could VW go from 1.7L to 2.0L on same system without running into problems with fuel/air starvation? Is my stock 2.0L only at 70 hp because stock FI is optimized for 1.7L engine it was originally fitted to?

Thanks. I think this is developing to be an interesting thread, there must be others interested in ways to increase performance in a Bus without busting the bank. We don't want to drag race, we just want to go up a mountain pass at 50 mph!!

Interesting article on rising rate pressure regulators, although note that its pitched at turbo systems:
http://mcbrooms.com/volvo/injcalcs/injcalcs.htm

also here, information on rising rate presure regulator and source for adjustable rising rate injector, although optimized for turbo Saab:
http://www.spg9.com/rrfpr.htm

One more on adjustable rising rate regulator:
http://www.928gt.com/FP-regulator.htm

And I pulled the following from this page:
http://www.cartech.net/fuelaccessories.html


The broad range of tuning capability available with changing fuel pressure has yet to be fully explored. We have pioneered this concept with the introduction of the rising rate fuel pressure regulator. It has been created for the purpose of increasing the fuel flow through electronic fuel injection systems when conditions of engine load demand more fuel. Unique to the concept of the rising rate regulator is that the pressure only increases when needed then returns to stock. This concept does not keep the fuel pressure up all the time, it just gives the system a correct mixture some of the time.
The concept of the rising rate regulator is particularly useful in three circumstances:
1. The factory turbo/supercharger car when the stock boost pressure is increased.
2. An aftermarket turbo/supercharger system applied to an EFI equipped car.
3. A normally aspirated EFI car with modifications that increase the air flow.

These regulators are unique in the adjustability of the rate of gain as well as the onset of gain. The potential for increasing fuel flows is very large, with as much as 40% more fuel available. The user/installer will find these regulators have far more potential for increasing fuel flows than microprocessor changes or additional injectors. Further, they are less expensive and tunable. The installer will also find they are very user friendly products. Installation and tuning are quite simple. The regulator installs in the EFI return line after the stock regulator and overrides the stock regulator at full throttle or when under boost. One truly unique feature of our design is the ability to begin raising the fuel pressure before getting under boost. The ability will tune out the inherent turbo/supercharger lean flat spot at the onset of boost.

Another interesting article, this one specifically addressing L-Jet tuning issue, pulled from this website, for credit, but I've posted it in full, aside from the pictures: http://www.viva-lancia.com/beta/ljet.html


L-Jetronic Fuel Injection

The L-Jetronic is an electronically controlled fuel-injection system which injects fuel intermittently into the intake manifold. In North America it is equipped with an oxygen sensor (Lambda sond) to monitor the emission. The electronic module to which all switches, sensors and injectors are connected is called an ECU (electronic control unit). This unit will control the amount of fuel that is to be injected based on how much air (throttle and airflow sensor) is coming in.
The ideal ratio is about 14.7 gram of air for 1 gram of fuel. With more fuel, you would get more power, but it would burn less cleanly. This is called a rich mixture. With less fuel, the fuel consumption is less but the power is less. If the ratio of actual air intake on the theorical amount is greater than 1.3 (19 grams at intake / 14.7 in our example) then the combustion will not take place anymore. The system is adjusted for a 1.0 ratio. Fooling the system it is at 1.0 when it's really at 0.9 could in theory bring the power up.

Other settings that affect the fuel-air mixture are the idle mixture adjusting screw on the air flow meter box, and the spring preloading ring wheel inside the box itself. The air flow meter on the L-jetronic system is a restrictive meter, but cant be adjusted much. By releasing the spring by 3 notch on the ring wheel, you will bring your power up a little, and the flap will open with less restriction, which will help the flow. In no way should this be moved by more than this or you will end up with either an overly rich mixture (or lean if you turn the other way). In any case, mark the wheel at the current setting before moving it. If the spring is broken or has detached itself or the AFM is not doing it's job properly, you will need a stoich meter, or at least connect an analog voltmeter to the O2 sensor to adjust the AFM at both idle and 2000+ rpm (the idle speed adjust on the intake manifold will help you raise the rpm to about 2000-2200 rpm if you are doing this on your own).



1 - Fuel tank
Fairly obvious, but there are a few things that can go wrong: it can rust and end up with holes and leak. To fix that, you can either replace it, or remove the gas, clean it with alcohol, then use a POR-15 kit to prep it and seal it. If there are leaks at a solder joint, have it resoldered. Check out Bruce's part bin in the links section, he sells this stuff. As for the application of POR-15 to a gas tank, that's something that Kevin Harper did to one of his Fiat 850 spider. The evaporative system is also fairly complex and could create a bunch of problems from fuel fumes in the cockpit to the car stalling. I will write up something on that subject another time.

2 - Electric fuel pump
Some cars have 2 electric fuels pumps; a pre-pump in the gas tank and a pump. The Lancia Beta only has 1. If the car doesn't start at all and doesn't smell like gas even after quite a few cranking, check the fuel pump fuse. Check also the power to the fuel pump when cranking. If you want to be sure, disconnect the fuel line after the fuel pump and crank. If there is no fuel coming out and the fuse is good, it's getting power (the green wire is +12v, the black is ground) you probably need a new pump. Do check the next element too...

3 - Fuel filter
the fuel filter needs to be changed on a regular basis. The Bosch part should be still available from a Bosch dealer. If you cant find it, a VW scirocco fuel filter fits, but do check out the part suppliers in my links page. Where is it? Under the car, partly hidden, close to the rear right side wheel (passenger side).

4 - Distributor pipe
Also called a fuel rail, this is right in front of the front cam box, under the air filter. I dont have any tips on this part. Do check for the obvious however like stress marks or cracks. If there are, try to find a replacement, as this could be a serious fire hazard.

5 - Pressure regulator
Bosch part again, I'll try to have the number soon. Same as the one in a Fiat Spider 2000 FI, and cross reference to the 82+ Alfa Spider too. There are some replacement parts of higher performance available. A few companies in the UK and at least one in italy make what is called a rising rate fuel regulator. James Seabolt has installed such a regulator on his spider.

6 - ECU
This is where the action is, but you cant rechip this to get better performance. Again dont have the number handy, but will have a section soon on this, including the pinout and things you can test.

7 - Injection valve
These are the valves that inject the fuel right behind the valves. On the Beta, the Bosch part number is 0 280 150 121. They should last forever, I wouldn't mess with them before I've tried everything else.

8 - Start valve
Also known as a cold start injector. If you have trouble starting your car when the engine is cold, this could be the problem (or it could also be the thermo-time switch).

9 - Idle-speed adjustment
10 - Throttle-valve switch
Bosch part number 0 280 120 300.

11 - Throttle-valve
12 - Air-flow sensor
Bosch part number 0 280 202 018.
drawings: air side, spring side

13 - Relay combination
14 - Lambda sensor
15 - Engine temperature sensor
16 - Thermo-time switch
17 - Ignition distributor
18 - Auxiliary-air device
This is a little bugger. If you have idle troubles when cold, there is a good chance that this is the cause. 19 - Idle-mixture adjustment
See the comment on the AFM in the text before the graphic.

20 - Battery
In the beta, you need a low profile battery, else you risk having the positive terminal touching the hood. That would result in total meltdown...

21 - Ignition-starter switch

Derek,
I just recently posted a thread about information that is included in this thread. I am planning on building a 2056 for my bus too and staying with the L-Jet.

Did you ever build your engine and if so what mods have you made to the L-jet and how has it turned out? I'm interested in how things may have worked out for you.

Thanks,
Casey www.angelfire.com/tx5/76vwbus