More horsepower on a fuel injected Super Beetle?

[Marius K]

I have asked a couple of mechanics what options there are to increase hp on a 1600 FI Super Beetle. One tells me the only thing you need to do is to put on "bigger jugs," and that the Bosch Jetronic automatically will do the rest of the job and deliver enough air and fuel. He estimated about 80 hp after the job being done (1900ccm). Another guy tells me I'm stuck with my 48 hp if I want to stay fuel injected, and that I will have to rebuild to carbs if I want more power. Do any of you gentlemen have experience in increasing the power on a fuel injected beetle? Is it possible? How many parts will have to be replaced, and can the stock muffler be used?

I live in Norway where the hills are pretty steep, so I need the extra power, but I want everything on the car to look as original as possible, including the engine.

[rzepko6194]

There isn't much you can do to increase HP with the stock FI system. There are however a few things which may help your bug "feel" quicker off the line.

Obviously, make sure the engine is not "tired" (do a compression test) and is fully tuned up. Advancing the timing to a max of 32 degrees, assuming you're using premium fuel, will help a bit. Be sure to listen for pinging afterwards. Carefully loosening the AFM flap spring a few clicks may help too. This will enrichen the fuel mixture a little bit earlier.

I've done these mods on mine and it definetly "feels" faster. Not sure if there are any additional horsepower benefits however.


JP

79' Vert

[Randy in Maine]

[Marius K]

Thank you very much for your advice and opinions. I am still a bit confused. Does this mean that the L-tronic and the injectors are incapable of delivering a sufficiant mixture if I were to replace the cylinders and pistons with larger ones? The Bentley VW Service Manual describes a screw underneath the intake air sensor that can be adjusted to enrichen the mixture, but will there be enough air and fuel flowing through? The manual also says the same control unit and system is being used on several other engines, but not how powerful an engine it can serve. Were there ever made fuel injected engines for eg the westfalia or other vehicles with a more powerful engine, and if so, was the same system used?

[Randy in Maine]

Well I am a 2.0 L type 4 engine in my bus but I am not sure about the difference in things like injector flow rates with a 1600 type 1 engine.

I was thinking that the stock type 1 FI system was pretty good as it came from the facotry and could be "adjusted" with a rising rate fuel pressure regulator, another fuel pump, and some CIS adjustments for up to about 2.0 liters+ of engine. I think a pretty good 1776 engine with some low end torque could be made just by use the stock FI system. There are a number of other systems out there also that may prove worthwhile.

I am not a mechanic nor do I play one on TV. I would pose that question to Ray Greenwood over here http://www.shoptalkforums.com/viewforum.php?f=23

I would also search around in there as someone has asked that very question I am sure.

Also that by pass screw just allows a certain amount of unmetered air past the AFM without counting it and has more effect on the total mix when the engine is at idle. In my 79 CA model bus so when I am hooked into the 5 gas EGA and with my O2 sensor unhooked (I don't have an idle stabilizer) at the catalitic converter, I can adjust the AFM bypass mixture screw to bring the system back into the correct CO range with that screw. In the states that is one of the numbers they are looking at for emission testing.

If you look inside the AFM are 2 "wheels" that the other guy was talking about. One adjusts the mixture for a "static map" condition and the other adjusts the mixture in a "dynamic mapping" process to allow for a richer mixture at a higher speed.

When you go to "tweak" things you must be very careful and have access to a gas analyzer along with a pretty good plan. Too lean or too rich of a condition and it will make short life of your engine as well as not giving you the HP kick you are looking for or any kind of fuel economy.

good luck!

[rzepko6194]

[Marius K]

Hmmm... Is there anyone out there who has replaced cylinders and pistons on a FI with larger ones, and who is willing to share their experience? Surely I can't be the only one who has wanted a few extra horsepowers out of my stock engine? My Super Beetle is an all original 79 convertible with less than 20k miles on it since new. It is important to me not to make any visual changes, just as few alterations as possible to get a little faster up the hills to my cabin...

[rzepko6194]

Call or email Dave at Bug City; www.bugcity.com. He may be able to help.

Good luck!

JP

79' Vert

[Randy in Maine]

Well that advice really was not all that bad I guess, I just hate to see people futzing around in the AFM unit with out a exhaust gas meter since it can do real harm to the engine. Sorry. I get cranky sometimes.

Another thought. You have a 79 car with 20K miles on it means that it has sat for periods of time with gas in it or driven on very short trips.

I have found both of those conditions to be very capable of clogging up your fuel injectors. If you lived here, I would suggest pulling out those injectors out (since you should change out your fuel lines anyway) and sending them off for cleaning and calibration.

I use this guy www.cruzinperfomance.com but there is somebody like him in Norway I would assume. For me it was $60 or so well spent. When he did the injecotrs in my jeep 2 of the injectors were not flowing very well and were not spraying in that cone shaped pattern that we want to see due to dead gas (as it had not been driven in about a year when I got it). Big improvement in power after the cleaning.

Here are some of the injectors that came in a bus engine that I sent in since I will be overhauling it this winter. They were actually pretty good but I wanted them to be 100% going in. He replaces all the hoses and seals also.

Test pressure = 43.5 psi Injector No.
1 2 3 4
Test 1. Injector Resistance 2.5 2.5 2.5 2.5
Test 2. Leak Down Test (Pass / Fail) P P P P
Test 3. Spray Pattern (Good / Fair / Poor) F F F F
Test 4. 90 Second Pulsed Flow Delivery (mL) 74 74 73 73
Test 5. 100mL Pulsed Volume 100 100 99 99
Test 6. 20 Second Static Flow (mL) 75 74 71 74
Test 7. 100mL Static Flow 100 99 96 99

Test Results After Service
Test pressure = 43.5 psi Injector No.
1 2 3 4 5 6 7 8
Test 1. Leak Down Test (Pass / Fail) P P P P
Test 2. Spray Pattern (Good / Fair / Poor) G G G G
Test 3. 90 Second Pulsed Flow Delivery (mL) 76 77 76 77
Test 4. 100mL Pulsed Volume 99 100 99 100
Test 5. 20 Second Static Flow (mL) 76 76 76 75
Test 6. 100mL Static Flow 100 100 100 99
Approximate pound-per-hour flow 19.5 19.5 19.5 19.24

Parts Replaced
Pintle Caps Seals O-Rings Screens Hoses Clips
4 8 0 4 0 4

Comments
Install customer supplied hoses.

Here is ratwell' report http://www.type2.com/archive/type2/122556.html


Also I don't know if it is the gas formulation that we use here or what, but short trips where the engine gets hot and then cools down seems to make the problem worse in air cooled VW than other water cooled cars as the oxidized gas sort of cakes on the tips of the injectors. That also will diminsh flow and create a poor spray pattern.

Once more thought before you spend any real money, would be to do a compression test and a leakdown test if required to ensure the engine is all that it can be right now. Engine warm and with and without the "oil squirt" in there.

[Marius K]

Thank you very much for all your useful info. I never would have guessed that the injectors can be calibrated. The engine is really not bad. It has been well maintained by the first and only other owner. Compared to other beetles I have owned it actually feels more powerful. It always starts the second I crank it, it idles a lot smoother than my earlier carburated ones, and it doesn't use or leak a single drop of oil. Even the push rod tubes are perfectly dry. Compression is excellent.

Part of me says it's stupid to start messing around with an engine that practically is a virgin. Another part of me is probably hoping there is a simple way to just bolt on bigger pistons and cylinders and then zoom away. Best thing is obviously to do as you suggest, and have the injectors, and maybe the AFM adjusted by professionals and see if I notice a difference...

By the way, how fast is an original Super Beetle supposed to run? And how quickly should it reach that speed? I'm not planning to take it to the race track, I just wonder what I should expect from 48 modust horsepowers. When my throttle pedal hits the floor I rarely see the needle above 80 mph (unless I go downhill.)

[jhicken]

Any modest modification will hardly be noticed. Even increasing the output 25% is only going to yield 12hp. Will you feel it, sure, will it make that much difference on an freeway onramp, probably not. Drive it awhile and you'll get used to its limitations. I've owned my '79 for 22 years. It's bone stock. 230,000 miles on the clock [rebuilt once at 191,000]. Is it fast? No way but it has always performed well enough to get me where I want to go safely. One side benefit, I've never received a speeding ticket while driving it.

One other thing, no matter how carefull you are, if you crack it open to swap barrels, it'll leak. Murphys law.

-jeffrey
_________________
Der Kleiner Kampfwagens

[rzepko6194]

[Mike J. Goode]

I think VW claimed a top speed of 82mph for those. Consumer Reports in '76 listed a 0-60 time of 16 secs, highway fuel mileage at 34mpg, and a top speed of 81mph. The fuel mileage was amongst the best of all the cars in its class. Performance was about average, maybe slightly below but not that bad for the day.

Use a search engine for Custom and Speed Parts-I think they offer hipo exhausts for Fuel Injected Bugs

[convertible79]

hmm, my convertible runs over 90 miles per hour, sometimes almost 95 and engine is bone stock, but rebuilt once. tires are stock radials, so odometer shows speed correctly.

[Marius K]

Maybe a stupid question, but how do I tell how many degrees advance timing I have on my beetle?

And another stupid question:
Did VW ever produce a special tool for replacing spark plugs on the FI engine? When having AC installed in addition to injectors, side mounted air cleaner and a bunch of hoses and wires you really need a few extra sets of joints on your arms to be able to reach them...

[Bugs'n'Pugs]

[NOVA Airhead]

You may want to check out this site for FI info and products:

http://www.cbperformance.com/default.asp
_________________
Ghia Owner Emeritus

[TiredandWornARTifacts]

[busdaddy]

Wow!, for that kind of $ it better be dramatic!
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!