the brick hits the dyno

Here's the place for info on converting to a Type V motor!
51MAN
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Post by 51MAN » Thu Dec 04, 2008 6:42 pm

:D PM'd yer..

farmer
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Post by farmer » Fri Feb 06, 2009 8:05 pm

Hello.
- Yes the CB2280 is THAT good. The ads dont brag. as for the ratio rockers on that cam. I would suggest that you only install 1,25 rockers on the intake since you are mainly after torque. it will most likely not make much of a difference up to about 2500 rpm. from thereon up to max power you will see an increase in torque and a little in HP.
The peak power is a little lower than a stock engine, but I´d bet it pulls well on the hills.

And yes, that is a very nice looking header for the bus. Where is the muffler located ? Are the primaries 1½" and 1 7/8" secondaries into 2" ?
T

tencentlife
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Post by tencentlife » Sat Feb 28, 2009 12:42 pm

Yup, it is a really great cam for a bus.

As I said, I had taken off the 1.25 rockers and put 1.1's back on because the intakes floated right at 5000rpm with stock springs on this cam. That dyno session was done with the 1.1's.

Finally got around to shimming the springs so I could return to 1.25's. I had to make up a special spring compressor tool to do them in the van, because the usual lever tool wouldn't clear the water pipe on the left side nor my exhaust pipes on the right. This thing works great, and you can work from above!:

Image

Image

Put a .030" shim under each intake, left the exhausts alone, and put on some shortened pushrods, and some 1.25 rockers. First time I'm trying the ones with adjusters on the pushrod end, stem caps and all that. I don't care for the geometry with this type, but I bought the set to check out so they'll stay on there unless there's any problems.

Once I got the oil warmed up the hydros readjusted themselves, just like clockwork. It revs right to 5500 with no valve float at all.
as for the ratio rockers on that cam. I would suggest that you only install 1,25 rockers on the intake since you are mainly after torque. it will most likely not make much of a difference up to about 2500 rpm. from thereon up to max power you will see an increase in torque and a little in HP.
So, here's the thing: with 1.25's on it, the off-idle torque is much diminished. Power in the mid-range is solid, and seems to be a little better in the top end as you'd expect, but not by much. The sound is way different, much louder and more throaty, but it just doesn't kick you in the butt as soon as you tip the throttle like it did with 1.1's. This was the same when I tried 1.1 vs. 1.25 on the intakes with the 2254 cam, too. The wbx intake dynamics seem to like a smaller valve opening for low-to-midrange torque; it must be due to better velocity in the port itself. I'd like to get it on the dyno again this way, budget allowing, so i'm not just comparing seat-of-the pants.

So, just like i found with the 2254, I think the lift configuration is going to be best with 1.1's on intake, and 1.25's on exhaust, especially now with my 4-2-1 exhaust on there. I'll drive it like this awhile, and hopefully get it on the dyno this way, but I think I'll be going to that rocker combo in the end for overall driveability.

And yes, that is a very nice looking header for the bus. Where is the muffler located ? Are the primaries 1½" and 1 7/8" secondaries into 2" ?
T
Thanks! I'm putting it into production. Primaries are 1.5" OD, step up to 1.625" secondaries, and 2" or 2.25" collector. Mine as shown has a short 2.25" collector, but I'm going back to 2" for the production versions because 2" is closer to the ideal diameter, and it's cheaper to manufacture in that size.

In the earlier picture, my van has the first prototype, and the collector is half-length with no catalyst. Production copies will have cat, or a straight pipe in lieu of cat, with the proper full-length tuned collector, like this one (although it is in 2.25"):
Image

The newest, final version is reworked so it fits all wbx's in Vanagons: 1.9, 2.1, and Syncros. For once Syncro owners won't have to pay extra! There are some other changes to make manufacturing easier and make the assemblies smaller for shipping, too.

regis101
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Post by regis101 » Sat Feb 28, 2009 1:04 pm

I've been trying to research hydraulic cams that will run with stock FI with some passion.

Most manufacturers use 255 (advertised or seat duration) as the limit. One the 260* mark is met, they disclaim them as an FI cam or at least , a little rough , with FI. Advertised is not the real number to worry about. The @.050 is the concerning number. With this, it seems that 220 is the cut off.
The 2205 for the Type 4 engine has such a disclaimer. What the...

Numerically, in my mind, the 2280 or the 2254 shouldn't work with FI. Maybe the later Bosch FI systems can tolerate a healthier cam than the L-jet? Dunno.

Educate me?

farmer
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Post by farmer » Sat Feb 28, 2009 1:15 pm

They understate what can be done to look after their own back. Somewhat depending on intake style and capacity you can run up to about 245 ish @ 0,050" with L-jet. D-jet on the other hand is VERY sensetive to other than stock cams. The Web 73 or the RAT version of it is about it with that system.
T

tencentlife
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Post by tencentlife » Sat Feb 28, 2009 1:40 pm

I'd be surprised if VW or Bosch ever had anything to say to that effect since they only ever discuss their stock applications; the art of tuning doesn't exist in their minds, and why should it?

I would be prone to chalk that notion up to the general mystification of FI over the years by people who haven't taken the time to understand it. Believe me, an L-jet FI is a lot less sensitive to duration than carbs would be. The ECU has some capacity to smooth out what it's receiving from the sensors, and Bosch went out of their way to incorporate mechanical smoothing in the vane potentiometer. There's a big dead-air space behind the vane that is specifically put there to damp down erratic movement of the vane, and believe me, it works as designed. When I had that 2254 in there, I spent hours and hours playing with the AFM, and the flap was not in the least bit more erratic with 234@.050" than it is with 214@.050"; in both cases, it sits there rock solid at idle, and only flinches when you tip the throttle.

I think you would have to get into pretty high-overlap conditions before the idle vac signature isn't sufficient to accomplish a stable signal coming out of the AFM. That's the only part of an L-jet that would be affected, and pretty much only at idle and very low rpms. Once you have some airflow coming in the volume overrides any possible pulsations. Even if the signal pulsed at idle, you could add a cap across the signal legs and smooth it right out electronically. that's what the fix for "Vanagon Syndrome" does already.

The D-jet manifold sensor is probably more sensitive, but once again, I think you could add a simple electronic fix that would smooth an erratic signal.

regis101
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Post by regis101 » Sat Feb 28, 2009 4:14 pm

It's common knowledge to not rely on advertised duration, hence the standard @.050 numbers. Still can't get too crazy with the @.050 if I'm looking for low and mid range performance. Maybe 230 at most. Maybe some of the trick is to keep lift tolerable, perhaps around .400

I have to keep in mind that I'm dealing with a 2.0 aircooled and ~7.5:1 CR.

It is settling on my mind that there are available cams out there that will work. Just need to dig around for them.

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pocketrocket
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Post by pocketrocket » Mon Mar 02, 2009 12:14 am

Tencent, that exhaust is just sic! What the _ell are you thinkin guy. Looks like it should make the vanagon do wheelies. Keep up the good work. Rocky

tencentlife
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Post by tencentlife » Mon Mar 02, 2009 11:11 am

Thanks, Rocky!

farmer
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Post by farmer » Sun Mar 22, 2009 1:40 pm

Hello.
Well, I was absent for a while.
I´m a little surprised that the 1,25 intake rocker made it loose bottom end torque. It must have something to do with the intake runners, maybe the length or volume of the runners compared to the intake charge.
With the stock progressive carb it worked great, - after a slight recureve oif the distributor though.

Before you ditch the idea complete ly, try and add 1,25´s on the exhaust as well. It may be, that this exhaust is so effective that it will aid in sucking in the required amount of mix in the lower rpms to keep the bottom end torque up and at the same time keep the added upper end power.
T

tencentlife
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Post by tencentlife » Sun Mar 22, 2009 5:53 pm

I'm using all 1.25's now, so the exhaust should be having its full scavenging effect.

I had the same observation when I tried 1.1 vs. 1.25 intake rockers with the 2254 cam: lower lift on the intake makes for really fat torque right off-idle and a fat low end. With both the 2280 and 2254 going to 1.25 on intakes makes off-idle throttle response sluggish and that fat bottom-end torque is much less.

2280 valve lift w/ 1.1 is .394"; w/1.25 is .448"

2254 valve lift w/ 1.1 is .350: ; w/ 1.25 is .395"

The overlap timing is also changed slightly when the lift ratio changes, as is the exact intake closing point. So partly there's a small compression increase when the lift ratio is lower, and a tiny bit less overlap. Just a couple degrees on either end, it's not much.

Anyway, the difference is pretty dramatic. It definitely has something to do with intake velocity, and different intake tracts would act differently in that case. What else is doing it is something to ponder.

I'm going to make up a rocker set with 1.1 intakes and 1.25 exhaust just to see if that's the best combo of all on the 2280. It was for sure the better combo on the 2254.

Possibly it has something to do with the ECU's timing advance response since this is Digifant. Changing the amount the AFM flap moves when you tip the throttle alters both load mixture and timing with this system.

51MAN
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Post by 51MAN » Sun Apr 19, 2009 1:15 pm

Nice work Chris....

I'd care not about the bit better top end for y syncro.. that off idle grunt is just whats needed when offroad and a syncro aint no highway blasting machine.. it also means it will pull the bigger offroad tyres too.. cool...

rockerarm
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Re: the brick hits the dyno

Post by rockerarm » Thu Jan 28, 2010 6:11 pm

tencentlife, I am really interested in your dedicated work with the WBX engine. I would like to ask you how do you like the CB line of cams. I have thought of installing the very same CB2280 into my '71 that has a small big bore kit(88mm), dual Kadron carbs, and 1 3/8 exhaust. Have you used there cams for very long. I have read threads on a few of the VW sites where people have had wear problems with Engle and Web cams. But I have yet to read anything problematic with the CB cams. Maybe it is because more people are using the Engle or Web products. I know CB has been around for decades, but just recently have given serious thought to there cams. I am not looking for maximum power but good torque curve as you have discussed in your thread. Plus I really do not want to loose sleep by having to resort to oil analysis to determine if my cam selection was wrong. I have worked at both the dealer network and independents so I can really appreciate your time consuming work. Thanks, Bill.

farmer
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Re: the brick hits the dyno

Post by farmer » Thu Jan 28, 2010 7:52 pm

I take the liberty to chime in here.
All cam manufactors have had these problems. Some more than others. But it generally has more to do with choice of lifters than the cam. It took me quite a while to figure that out. And I got "pushed " in the right direction by well known and respected builders.

- The 2280 is a good choice for an aircooled bus too. It makes a very good power/torque band, and helps the engine to be comfortable at freeway speeds too.
another good choice for that would be the Scat C25.
T

tencentlife
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Re: the brick hits the dyno

Post by tencentlife » Thu Jan 28, 2010 9:52 pm

Hey there, rockerarm, thanks for the kind words. I like doing what I'm doing and I'm sure I'm not the only one.

As you can see from reading this thread I do like the 2280, it was developed as a bus cam and they did a good job. I think it's been around for quite awhile. It's just lucky for me that it clears the small-face (T4) hydro lifters in a wbx, because it has a great torque curve for a Vanagon. I've been using CB cams for about 3 years and not a single problem yet, I've had the chance to remove lifters from a few engines with some use on them and all have looked nice. They've all been run with an OEM hydro lifter, and these are the ones CB sells. Either they've made a good choice of matching those lifters to their cams, or they got lucky, but it seems like a good match. All of my engines have been run in carefully at 2k rpm for over 20 minutes with high-ZDDP oils.

Their 2252 made a nice bus cam, too, less torquey but it had a good upper mid-range, more of a nice highway grind.

I have to say also that I've been pleased with CB's parts on the whole, I use a lot of their stuff and they have not let me down. Their cams are always a tight fit on a double-thrust Mahle set in a wbx, I've heard the same for T1 cases, but that's good because I like to hone cam endplay pretty snug. And gotta watch the threading on their 9mm rockers, that's about all I recall. I went back to 8's so I almost forgot about that.

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