chrisfiat
Veteran Member
lower your IQ to around 3.5 to 4 and the shudder will go away
Some of us have already tried IQ adjustments with out improvement.....lower your IQ to around 3.5 to 4 and the shudder will go away
Have you ever had the problem? Your about the first one with similar mods that does not.I had an opportunity to test this today on the freeway during my shakedown run for my new clutch. I wound up behind a slow car doing about 40 on a uniformly moderate grade. I thought of this thread so I held behind him in 5th for a few seconds, then went to pass, pushing to about 1/2 pedal. I could not detect a shudder or poor running. Car has RC-2 and titan 502's.
I've tried IQ from 3-6 with no improvement Abacus. I might try less than 3 and if it helps maybe I'll live with the smoke.Some of us have already tried IQ adjustments with out improvement.....
What are the ambient temperatures where you live? I noticed the problem was worse when it was cold out, around 25 * farenheitI've had the car for about a year and a half, and I can't say I've noticed it before or after the RC-2 tune which Jeff did in Spring 2011. Timing is adapted advanced about 2 degrees, and IQ is currently about 5.5 which gives a haze with the Titan 502 (.205) nozzles. There is another steeper grade up a rural city street near me. The speed limit is 35 mph, and I regularly drive that in 4th very easily with no shudder.
Good point- I did lower the IQ to 2.8-3 on the sprint 520 car and sure enough it did go away. Still having issues with the PP520 car though. I can get the shudder to almost go away at IQ=3.0 but it starts smoking then under heavy acceleration. As I raise it point by point,the shudder comes back as the smoking subsides so for now,I'll keep it at 3.0 and hopefully someone will come up with a fix. Both injector sets were low smoke calibrated by Kerma. That may be my whole problem. Since the sprints are close to stock ,it makes sense they were easier to IQ adjust the shudder away. These cars are very sensitive to IQ,so I would advise everyone to test at every .2 point starting at 2.8.lower your IQ to around 3.5 to 4 and the shudder will go away
Per my last post, it seems to work on the smaller sprint nozzles but the PP520s are still a problem. Also temp doesn't seem to matter.I've tried IQ from 3-6 with no improvement Abacus. I might try less than 3 and if it helps maybe I'll live with the smoke.
You are incorrect.... I ran factory Bosch 520 nozzles with stock chipset in my 1998 jetta tdi, and my 5th gear would pull cleanly off of 1100 rpm. IQ was set at 4.5, stock 195-60-14 tires on stock aluminum alloy rims.That's not shudder. That's lugging. In 4th and 5th you are in 'overdrive'. Around 1750-1800 is the lowest you can go in either gear and the engine is struggling a bit to keep on power while spinning too slowly.
If I'm wrong, please feel free to correct me, but from my research here on the club about shift points and how the engine feels. With the vibration being characteristic of lugging when in 1st-3rd but extending to a slightly RPM range makes sense since the gearing in 4th and 5 puts the engine at a mechanical disadvantage.
I've done two hot swaps with Kerma. No problems. Just make sure you take the bolt and tubing barb fitting off #2 or 3 for the bypass or you won't get it back. Kerma definitely has pop capabilty and gives you the numbers for each injector when he sends them back. If Drivebywire sees this thread, he'll comment. I've found Paul to be very accomodating if there are any issues.That's something else I was wondering.... how many people are doing the hot swap program? Having the injectors matched may help the issue.
Are DBW, LLC and Kerma the same company? 2 different sites with different pricing. DBW claims that his company is the only one with the specialized equipment to properly set the pop pressures on these nozzles.
One site offers the hot swap, but also mentions letting the nozzles run in for 500 miles. I thought this was confusing.
-Todd
Did the injectors stop your shuttuddering(TM)?I have a RC2+ and am very happy with it, but still have the shudder despite the non-winter fuel. I just got the PP520's back from Kerma (DBW) and will see if the shudder is still present with them. If so, I'll put a switch inline with the VSS and see if that makes a difference. It is annoying.