I have a 100kw 4AGE running in my Sprinter and i am considering fitting some mild cams to it. I am hoping to hear back from people that HAVE ACTUALLY FITTED CAMS (please no refences to websites with limited information and theories). I would like to know whether any modifications were needed for the rest of the valvetrain and how the car behaved and performed. What duration cams were used and were adjustable cam gears used or recommended. How did the computer react to the new cams etc. An idea of brands and costing would also be helpful. Also what options do i have for tuning the computer whether chipping or a piggyback unit is possible and worthwhile.
Any feedback would be great.
I've just fitted HKS 272 intake and exhaust cams with adjustable cam wheels to my 100kW factory EFI Sprinter.
Let me just say that the thing was running fantastically before I installed the new cams.
Having understood that the maximum the factory efi could cope with was 272 degrees duration, I got the HKS 272s.
Having translated the Japanese instructions it turns out that the duration is far greater than 272 degrees - something about 293 for the intake and 280-odd for the exhaust (they're different.
You'll need to check how the cam manufacturer describes duration. It turns out that HKS measures duration at 50 thou lift - giving in my case the label 272 - however the total duration (ie from 0mm lift) is far greater.
As a result the thing is almost undriveable below 2000 rpm. The idle drops to about 500 until the ECU decides it needs to do something about that and the revs rise to 900-odd.
Taking off from rest requires at least 1800-2000 rpm and then the thing bogs down and goes absolutely nowhere.
Backing off and coasting - as towards a set of red lights - the thing goes so rich and chugs back and forth very embarrassingly.
Suffice to say, I need to do some revisions to the EFI to get the thing working adequately.
I'll have a look at the specs for the 256s and 264s from HKS and check their actual duration.
I installed a mild cam setup from Wade. I cant remember the specs onthe cam, but they didnt require adjustable cam gears or larger springs/retainers.
My ae92 Gti was excellent before i installed the Cams.
Afterwards, i obviously had a lumpier idle sounding much like a ported Rotory. I eventually had to increase idle rpm to 1K7 rpm to prevent it from stalling.
Anywhere below 5K and the car whent nowhere. 5-7,500 rpm and the car was at its best.
I did not have my ecu piggybacked with an interceptor to tune for the new cams, and also the 4age ran with a map sensor, and lost alot of vacuum during idle due to the larger overlap and duration. But it was bearable, and the inductin noise changed and was awesome.
Although performance wise i was still dissapointed.
New billet cams cost me about $600.
You defintately need an interceptor or an new ECU to take advantage of the new cams.
Fri, 04 April 2003 07:56
Re: 4AGE cams and ECU questions
