High rpm guys: anybody playing with cam timing?

[TDIMeister]

Custom grinds for diesels have been done before, a few even for the TDI in Europe and the gains vs. the trade off of losing low end torque turned out to really not be worth it.

Most of the European TDI cams I've looked at (Dbilas, Piper, Sorg) are also regrinds and while I won't confirm or question their HP claims (approx. 15 HP), I found many of them to have way too much duration... One cam in my database advertises 272 degrees of duration at the intake, most are north of 250 degrees at lash).  This on an engine that redlines at 5100 RPM fer cryin out loud!

I deliberately kept the duration conservative at 209/204 @ .050.  It's not flashy and won't give "paper" gains north of 6000 RPM :roll:.  It softens the bottom end a touch, but hey, everything's a compromise, right; it depends on what individual's priorities are.  I tried to preserve the low-end as much as possible while targeting better breathing at a realistic upper limit of the TDI's rev range, meaning upto 5250 RPM.

I think as much is gained through the higher lift than stock about (1.5mm more) than the extra duration...

There, you know basically everything about the cams, but I reserve to hold on to the precise timings and lifts, etc., until I see some numbers to validate my predictions (or not).  Copy it if you want to try.  I have better things lined up. [/list]

[QuickTD]

OK, my bad. I was going from second-hand information from somewhere I don't remember that someone had tried to fit a cam from an ME into a TDI. The AAZ and 1Z/AHU swap nicely, but IIRC the was some issue over fitting the ME cam into the TDI. I must have mixed something up... maybe the issue was over valve-to-piston clearance...

I think the the fitment problem is with the locking tool/vacuum pump drive slot on the ALH TDI. Previous diesels have this slot machined about 4mm off centre so the locking tool lies flat on the head surface. I beleive the ALH slot is closer to being centred.

 All previous diesel cams, all the way back to the 1.5 and 1.6 solid lifter engines will happily interchange. I know of at least one person that ran a 1.6 cam in his AHU TDI for a while.

[RabbitGTDguy]

I'm going to try to dig out cam specs on the respective units tonight. It'd be nice to see what the different units may have to offer ...

Joe

[TDIMeister]

I'd be interested to know too.  I have a little database with some OE VW gas and Diesel cams.  One the Diesel side, I only have AAZ, SDI and TDI cam specs, but none from the earlier 1.5/1.6 Diesels.

Another member on both forums, SpikeTDI, had done some investigations and simulation using the same software as me.  He had come up with a cam profile that looked very good, but I have not succeded in getting in touch with him.

 
Discussion thread  here.

I would like for him to run an analysis of his cam using the same baseline engine file I developed here.

[TDIMeister]

Some more good discussions here:
http://forums.tdiclub.com/showthread.php?t=84939
http://forums.tdiclub.com/showthread.php?t=13734

[malone]

We don't really know what the 12mm pump will do much over 4,000 RPM, but several Europeans (Stefan @ Digital Racing, TDIFreak in Finland, etc.) are running 12mm pumps and don't report problems up to the TDI's conventional redline... I seem to be more keen on the 12mm than Gerry but to answer your question, Gerry's truck is running an 11mm and a 12mm just waiting to be used.

The general consensus at tdiclub.com (for what it's worth) is that the 11mm is ok up to 5,500 RPM. Beyond that, maybe. The 12mm according to Bosch info max out at 2,100 RPM, give or take 100 RPM.. approx. 4,400 RPM crank. Some people may push it a little further, but 5,500 RPM crank is quite out there.

I have 10mm (stock IDI = 9mm), 11mm, and 12mm parts... I was only curious as to know if Gerry has overcome the low-RPM issue with 12mm. My pump will be tested on a Bosch dyno at a pump shop so we'll see how it goes with each upgrade. For the record, my pump must be built for max. 3,500 RPM (7,000 RPM crank).

As for timing advance, Gerry and I have met with Jeff @ Rocketchip several times since Waterfest 2004 and he has shown us his pump mod in the timing control collar to allow greater advance.  Gerry is in the process to do that mod over this winter.

Do you know how many degrees advance?

I vaguely recall in 2004 that Jeff was interested in building a revver TDI (I could be wrong.. I did talk with him about making my ALH TDI rev high), but it looks like he has max. 4,000-4,500 RPM with 12mm pump today, which makes his pump timing advance mod seem obsolete, just for his application.

Another member on both forums, SpikeTDI, had done some investigations and simulation using the same software as me.  He had come up with a cam profile that looked very good, but I have not succeded in getting in touch with him.

He has been spending more time in the hospital than out lately.

[TDIMeister]

The general consensus at tdiclub.com (for what it's worth) is that the 11mm is ok up to 5,500 RPM. Beyond that, maybe. The 12mm according to Bosch info max out at 2,100 RPM, give or take 100 RPM.. approx. 4,400 RPM crank. Some people may push it a little further, but 5,500 RPM crank is quite out there.

I have 10mm (stock IDI = 9mm), 11mm, and 12mm parts... I was only curious as to know if Gerry has overcome the low-RPM issue with 12mm. My pump will be tested on a Bosch dyno at a pump shop so we'll see how it goes with each upgrade. For the record, my pump must be built for max. 3,500 RPM (7,000 RPM crank).

As for timing advance, Gerry and I have met with Jeff @ Rocketchip several times since Waterfest 2004 and he has shown us his pump mod in the timing control collar to allow greater advance.  Gerry is in the process to do that mod over this winter.

Do you know how many degrees advance?

I received this PM from Gerry just a few hours ago:

HI Dave I got the motor out and the 22 back on with my new intake.Modified the pump so it gets more advance.
I cut the top off a IZ manifold and welded on 3 inch tube with a slot in the tube to match the manifold,inlet on the end.
Planning on tearing down the trans soon and getting a diff from JRP.
Got a electric FP that I want to hook up too.
Got to find some slicks too.
Still working on a better boost control, I think i should open up the vanes some more on the 22 to keep the speed down.

As I recall (and this is going strictly from memory, so take it FWIW), you hit the stop on the timing collar at about 27 degs.  Jeff showed us how we can through some machining increase this to about 35 degs.  Don't know where this will take us in terms of RPM potential.  Obviously programming will have to play along, and I don't know what is the limit that the ECU can address...

I vaguely recall in 2004 that Jeff was interested in building a revver TDI (I could be wrong.. I did talk with him about making my ALH TDI rev high), but it looks like he has max. 4,000-4,500 RPM with 12mm pump today, which makes his pump timing advance mod seem obsolete, just for his application.

Another member on both forums, SpikeTDI, had done some investigations and simulation using the same software as me.  He had come up with a cam profile that looked very good, but I have not succeded in getting in touch with him.

He has been spending more time in the hospital than out lately.

I'm very sorry to hear that.  We have had some good discussions (and arguments) off-line and on (almost in that order, respectively...) I hope he gets better from whatever ails him.  If you or anyone else reading this are in contact with him, please send him my best regards.


Dave