Getting the most out of a 2.0!

[paulhagedorn]

I may be rebuilding my engine soon, and was wondering what i could do to give it a little more power while sticking with the fuel injection.

Can i put a different cam in it without having to remap the fuel injection, which seems impossible without getting a completely different system?

Installing the european 8.0:1 compression pistons gives a little more power...how much higher can i raise the compression, and what is the easiest way?

Can I put bigger P/C 's in and keep the original FI?

What else can I do? And about how much horsepower is the "limit" to the FI without throwing in mass amounts of money. I do have an external oil cooler I can throw onto it.

I want to keep the reliability of the engine also.

I do have an MSD 6A ignition on it, which helps the engine to run smoother.

How much does it cost to have someone balance and blueprint an engine?

Thanks a lot,
Paul

[jmcleod]

have you looked into the 96mm p/c offered by mark stephens? in the current issue of hot vw's (or vw trends) there is an article about an install into a vw van. the pistons are valve relieved (? things in piston heads to clear valve heads) and the package price seemed attractive. i've seen this on their web site too. i think i've read that stock fi works with 96mm.

[Ian_G]

I just rebuilt my 2L and stuck with the stock FI. Here is my take on things:

1. You can run the mild web cam for FI. It works great and you get a longer pull, up through 6K.

2. Lighten the flywheel. It should cost ~$100-150 from your machine shop and makes a big difference in the long run.

3. I got the Euro P&C's and they are fine. My engine was pumping up to 90psi when I rebuilt it, so I can't say how much better they are over US Stock.


Now here is the thing. I'd heard that you can get the FI to deal with 2.2 and even 2.4L conversions but did not want to risk it. Well 6mo later and after trouble shooting the FI completely in the interum I wish I had got to at least 2.2L! It's a relativally easy thing to calibrate the FI for larger displacements. The only thing you might have to modiy are the actual fuel injectors. The problem that you can run into is bad atomization of the gas at high fuel line pressures (like above 34psi which you would have to run) so you need to have the injectors ported to handle higher line pressures.

my $0.02
Ian

[paulhagedorn]

When going up to 2.2L I imagine all that involves is bigger P/C 's. I have only had a 1.7 apart and am wondering, is there as much gap when you have the cylinders off in a 2.0 so that you can have the piston in the block and wiggle it.

In other words, are the P/C 's a direct bolt on, or would I have to bore out the block?
I imagine that it would be producing a little more heat so an external oil cooler would be necessary.

I most likely can lighten the flywheel my self. The question, has anyone done this and balanced it. How much do I take off? Somewhere I remember you can take it down to about 12 pounds, not sure though.

I should also, while I am at it if I rebuild, get the bigger oil pump.

Who would be able to adjust the fuel injectors?

My car is a 73, and where I live, I don't even have to go through emissions...so I can throw on carburetors. I do have a set of dual dellortos that were on a 1.7.

Thanks again,
Paul

[Ian_G]

Paul,

I'm sorry I should have elaborated. I took the whole things down. I had every thing balanced to 10K, after lightening the flywheel. I went to a good machinest for this.

As for the oil cooler and pump. Well I got the big pump because it could only help, no? The oil cooler was already present as I live in Atlanta and heat is a concern.

As for the P&C's, well I do believe that you have to have the block and heads machined for them to fit. I've seen a 2.2L and it looks identical to the 2L. I've also seem a set of 3L P&C, not in the car and they are stupid big.

The injectors just have to be ported slightly for better spray pattern. I doubt that you'd have to do this for a 2.2L, but definateally for a 2.4L. If you locate a local speed shop that sells nitrous equipment they will be able to point you at injector tuners.

The reason for this is that you will be needing to pump more gas to the cylinders. Now using an O2 sensor this is easliy dont by calibrating your MPS at 2500 rpm and then running up the fuel pressure until you get good flow at high rpm. The thing is that over 34psi the 2L injectors (green caps) tend not to atomize/nebulize the gas well. You stop getting a gas mist and start getting large gas drops and streams. You can get the injectors tuned slightly, again folks that install nitrous systems sometimes do this. Then again you might not need to do this.

Ian

Again I wish I had built a 2.2L now that it's all over with. But I stuck with a 2L with a mild web cam for FI. Also lightened the cons and flywheel. Got every thing balanced to 10K rpm. Then all the simple mods that increase life; oil cooler, big oil pump, completely rebuilt heads with new sodium valves. . .

[paulhagedorn]

Thanks for the info Ian. I think, if I do it, just to be on the safe side, I will have the injectors tuned. Besides, if the injectors are tuned to perfectly match the engine size, wouldn't it give just a little more power? I am also in Atlanta right now, but do not have my oil cooler installed. Can't exactly remember what the psi in each cylinder was...i have that in the car...and will post it later.
The only time that I have been worried about the temp was when I was driving the car home. I was using a resistor to tell the engine how much fuel it needed because I broke the head where the temp sensor screws in.

I already have rebuilt heads waiting at home to be thrown on. I guess I am going to have them machined....hopefully!!!

Do you know what kind of cam I could put in with the bigger P/C's? Would stock work. I would think so since it would be the same duration for exhaust/intake. But, what would give a little extra power and be compatible with the FI...the mild web cam? Where can I get one/look at one online?
Also, who sells the 2.2L pistons?

Thanks a lot.

Paul

[JP Noonan]

1. As far as I have learned from a lot of reading and some (O.K. not much, but some) experience, the 1.7L (90mm) through 2.2L (96mm) are a direct fit into the "spigot" hole of any type-4 case. It is the head on a 1.7L that needs to be machined to accept anything over a 1.7L designed P/C. That said I think there are still some 96mm 1.7L big bore kits made by someone (markstephenshp.com I think) so that may be the way to go. Otherwise 1.8L (93mm stock) or 1.8 big bore kits could be used with a modification to the head. However 2.0L (94mm stock) and 2.0L BB kits CAN NOT be used with a 1.7L or 1.8L crank and rods. The wrist pin is located for a different stroke. To fit the 100mm-104mm P/C's you probably need to machine the case and the heads. Cranks are O.K. until 76-78mm then internal clearences get tight, the rods and internal structure of the case need to be machined.

2. If you increase displacement it is neccesary to increase valve size and ports to take advantage of the cc's. Volumetric effeciency of an engine is a system, approach it likewise. From what I've read the D-Jet was designed fairly well, there weren't the emmisions/MPG issues that killed cars in the 70-80's (retarded ignition timing, retarded cams, lower compression...) so if you go much beyond the stock displacement (2.3L+) look at boreing out the throttle body, bigger injectors, ported heads, etc.

3. Lightened FW's simply remove rotating mass. Good because it lets the engine rev up quicker, bad because it lets the engine rev down quicker. Some people love it, but it does change driveability, maybe it is offset by the extra hp? Ask Ian if you can test drive his car

4. People argue about cams all the time, the stock one is pretty good. The modified cams don't offer much except to move things around, more top end-less low end, a lot of top end-no low end.

What ever you do, figure out from the beginning a plan, a timtable, and a budget. Following what someone else (like Ian) has done with success is a good idea. Or talk to an engine builder (FATS, Mark Stephens). If you want to keep the D-JET with a highly modified motor it will cost money, see if an aftermarket FI is cheaper in the long run.

[neilca]

JP,
What is the compression height of a 2.0 and a 1.7? I was told by a local expert that these are the same. I need to know this for one of my motors.
Thanks,
neil

[Ian_G]

I'd agree on getting the valves ported slightly for this. Again this would best be done on a good flow bench. The other thing that you will have to ask folks that have 2.2's is if you need to bore out the throttle body?

Again I lean towards the 2.2 only because it seems that there are really small things that have to be done to a 2L to make it work well. I know that the 2.4 needs a bored throttle body and big valves. . .

As far as cams I would recomend the mild Webcam to most all folks. It works great with the stock FI and just rev's great. The other reason is that I've always heard (mainly from old hippie hauler owners) is that you don't ever want to lug these little engines. That just tears them up. Well OK so I keep the rev's up

I would invite you to drive my 2L however I'm pulling the alternator (again) tonight and trying to get the charging system to work. Man it's frusterating as all get out to have everything right on and this weather and the damn charging system goes belly up!

Ian

BTW paul email me privately and when I get thh charging system up and going we could meet. I just got engaged and will do most anything to get away from all the prep work that goes on durring the weekends.

[JP Noonan]

Lugging the motor is bad, especialy on a bus. A lot of people do it thinking the sooner they get into a higher gear the better the MPG. Unfortunatley the down side is it bends the crank!

I don't know about "compression hieght" I worked in a machine shop, maybe I'm daft (well, yes I am daft, but I digress) or we used different terminology. Do you mean "deck height"? In that case it is probably the same between motors, and yes it has a huge impact on CR. On any motor, but particularly on a air cooled VW, check the deck height of each cylinder, also cc each combustion chamber. Then figure out if the combustion chambers need to be grinded down to match with in a certain tolerance, and what base shims are needed to match all the deck heights (note: Bob Hoover contends that it is important to only use ONE BASE SHIM PER CYLINDER to avoid leaks. i.e. if the shim required is .060" use a .060" shim NOT two .030" shims or the motor will leak at the base) There are many sorces for recomended deck height and the formula for CR...I can't seem to find any of mine right now (haven't seen my Lash manual in about 6 months, must have put it in a safe place). Lower than 7.5:1 is a dog, above 8:5-9:1 is a problem on street gas.

Finding deck hieght is pretty cheap/simple. Torque down the cylinder with some sockets or washers instead of the head, then use a staight edge and feeler gauge. Combustion chamber volume involes a "burrette" (remember titrating acids in high school?) and thoses are an expensive one use in a liftime type of thing.

[neilca]

The compression height is the distance from the top of the piston to the center of the rod pin. This number allows you to compare pistons without worrying about rod configurations.
Thanks,
neil

[JP Noonan]

That makes sense to me. I always think of it as the wrist pin location but you're more correct. Anyway, I had a 2.0L crank and rods and used an old set of 1.7L P/C's in a mock up before I bought some 1.7L BB P/C's. The piston comes about 3/8" out of the bore, so the two cranks aren't interchangeable with P/C's. My reasoning was that I had some good, (high compresion, and have 1.8L valves) 1.7L heads and the 1.7L BB at the time was only $160 vs rebuilding my 2.0L heads $200 and 2.0L P/C's $400-450. Maybe all the 100mm,103mm, and 104.5mm are the same but I don't think the 1.7/1.8 are compatable with the 71mm (2.0L) crank. If shims were used to make the 1.7L P/C's work (FATS make made to order shims) then valve train geometry would be all kinds of off. Longer pushrods would probably cure it but the tin ware wouldn't fit right, and by then you're up to the price of 2.0L P/C's.

Funny thing is I have a 1.8L rod and a 2.0L rod in front of me and it seems the 2.0L is shorter which would indicate that your mechanic is right and the rods are different but piston pin height is the same. I dunno, remind me in a week and I'll dig up my old 1.7L,1.8L and 2.0L pistons to comare, along with the spec book.

[Dave at Pelican Parts]

Funny, on p. 45 of Wilson's VW Rebuild book, he has a photo of 1.7 and 2.0 rods side by side. They *look* to be the same length...

--DD

[neilca]

Gentlemen,
According to my notes the 2.0 rod is 131mm. The 1.8/1.7 is 127mm. These measurments are from the center of the small end to the center of the big end. They both have 24mm small ends. The 2.0 has 50mm big end and the 1.8/1.7 has a 55mm big end. Essentially, VW made a stroker crank by machining the back side of the 1.8/1.7 crank. Thus the 5mm smaller big end of the 2.0. The rods were changed to accomadate the smaller big end bearing on the 2.0 but did they also adjust the compression height? Sounds like JP experience says they did change this, but I would like the actual numbers. The rod lengths were not what seemed to be, but that is accurate data.
neil

[John Rogers]

There has been little mention of keeping things cool, but if you are going to higher compression and/or bigger P/Cs then I would really seriously consider one of the 911 fan type conversions and/or installing an external oil cooler with a fan even. Since you live down south, in the summer a large high compression engine could cook itself pretty easily. At an autocross this past weekend I noticed a couple of 914s with the cooler mounted on the engine lid with an electric fan which is better than none, but I would opt to have the cooler out in a fresh air stream so it would work even better. Good luck.

[Dave at Pelican Parts]

Hmm... I'm not really answering the question, and I don't even have numbers for the question that I am answering. Ya know, this would be the point where a sane person would shut up and let people who *aren't* guessing chime in. Lucky for me I'm not sane....

From the photo, it appears as if the difference between the 1.7 and 2.0 rod is that the hole for the big end has been moved. The end cap is in the same place, the top of the small end is in the same place, but the "I-beam" part of the rod is longer.

--DD

[JP Noonan]

He-he, did I say the 2.0L was shorter? Whoops, O.K. never underestimate the power to ignore permanat marker "76-79 2.0L VW bus" writen in your own hand writting on the rod. That and the balance pad on the 1.8L.
Anyway, I whipped out the cheapo plastic dial calipers and came up with the same numbers.

For DD, taking the end cap off and standing both rods on a table next to each other the top of the bearing sadle on the 1.8L rod is 3mm higher than the 2.0L (remember CHEAP PLASTIC calipers, maybe 2.5mm, can't measure real well with the fillet/radius on the edge) 26mm 2.0 vs 29mm 1.8 (BTW the 1.8L rod came from a blown motor and has some blueing but looks to be straight). The middle of the 1.8L pin end is 127mm the 2.0L is 131mm.

Offset grinding to stroke a motor is pretty common (look in the back of a Ford SVO catalog, it has all kinds of cool diagrams about stroking, valve train geo, Vol. Eff.) but to keep the piston under the deck either a shorter rod or a new wrist pin location is needed. Longer rods make more torque, I guess that's why VW went with the new piston.

[neilca]

I have thought of this some more and of course came up with more questions. Is it possible that the big end hole is the only change? Why would VW change the pistons, unless they were changing them anyway?..say for pollution reasons or higher compression. The compression height would tell us this for sure.

I have enjoyed this string. Being an engineer , I like to get down to smallest details and work with actual numbers.
Thanks guys,
neil

[Dave at Pelican Parts]

JP, it makes sense that the 2.0 rod would be longer measured that way.

If the overall length of the rods is the same, but you remove half of a smaller circle (the smaller "big end" of the 2.0 rod), you are taking less length away. So the 2.0 rod, without half of the circle that is the big end (half of that circle is the end cap) would be longer than the 1.8 rod measured the same way.


OK, I'm totally lost now. What did this have to do with compression height?

--DD

[neilca]

Dave,
I collected more data. I have two sets of jugs, one is 96 mm for a 1.7/1.8. The other set is 103mm for a 2.0. The 2.0 jugs are about 1/16 longer (head to case) than the 1.7/1.8. The plot thickens. I believe JP will find two different compression heights when he measures his pistons.
neil