[paulclaude]

Originally Posted by TTFS

I hear you on the cams however your making the assumption that the keyway that lines up the cam pickup wheel is in the correct position in relation to the cam lobes. All the ecu has to go by is the pickup wheel. So for example if the cam manufacturer ground 2 degrees of advance on the intake the ecu has no way of knowing this and your vanos maps would be off by that amount. One would think what would be the reason for doing that if you have the vanos to advance or retard right? Well if you index a stock cam and 288 you might be surprised what you find. I did it, and the cam we checked was off by 5 degrees
In comparison to a stock cam. Maybe they have done this for the guys who do vanos deletes, I can't answer that question that would be one for the cam manuafter. Again, I am not saying it can be solved by tuning it thru the dme but, it would be a whole lot easier if we actually knew where the cams are positioned in relation to tdc. Without indexing the cams or putting a degree wheel on the engine your only hope it that the cams are made to exact tolerances every time and they are truly ground to the cam card specs. This is what we have found so I figured I would share it. Maybe I am too old school but if I had a dollar for every time I built and engine and put a degree wheel on it index that turned out to be off I could probably be in the Carribian right now under a palm tree with a beer.

Team TTFS

TTFS - very interesting findings. Perhaps this explains why some people (including myself) have required a fairly negative offset with the 288/280's to get the cams near zero adaptation, despite the mechanical timing being spot on? I can't think of any real reason for this either, unless it's something to do with where they think the cams should sit for optimal HP. I agree that you are fully relying on the pickup key-way being accurate, or everything based on calculation is thrown out the window.

Nothing wrong with the old school method of thinking - that's obviously important even with todays technology. I'd also quite happily be sitting in the Caribbean sipping on a beer

[dafoe]

Frank/TTFS is spot on here guys. It was my car, at the shop, with me, Frank, Stash1 and Austin (can't remember his forum user name), working with Frank most of the afternoon, and night until 2am...

On HIS dyno, not dynojet calibrated, my car did a base run at about 260ish whp (I was WAY wrong on the butt dyno!) and some GOD awful torque number like 230ish... Left with 340whp, and 278wtq. We found the cams were off by 8 degrees....

[stash1]

Originally Posted by dafoe

Frank/TTFS is spot on here guys. It was my car, at the shop, with me, Frank, Stash1 and Austin (can't remember his forum user name), working with Frank most of the afternoon, and night until 2am...

On HIS dyno, not dynojet calibrated, my car did a base run at about 260ish whp (I was WAY wrong on the butt dyno!) and some GOD awful torque number like 230ish... Left with 340whp, and 278wtq. We found the cams were off by 8 degrees....

Yerp, that was a fun night! We've known about this issue (after Frank discovered it) for a little while, but wanted to test it out on a couple different cars first-before spilling the beans. (That's why I've been hinting around cam timing in a few of my posts for a while, but didn't want to all the way-sorry guys). Frank has applied this theory to at least 3 cars now (Dafoe, mine, and one other that I know of), and all 3 were very much inexplicably down on power at first...then made pretty huge gains in power after Frank worked his magic. Let me also say that this was not a quick process by any means...it required many hrs. of hard work and late nights on Frank's part to get these 3 cars right!

[HassanEido]

Originally Posted by TTFS

I hear you on the cams however your making the assumption that the keyway that lines up the cam pickup wheel is in the correct position in relation to the cam lobes. All the ecu has to go by is the pickup wheel. So for example if the cam manufacturer ground 2 degrees of advance on the intake the ecu has no way of knowing this and your vanos maps would be off by that amount. One would think what would be the reason for doing that if you have the vanos to advance or retard right? Well if you index a stock cam and 288 you might be surprised what you find. I did it, and the cam we checked was off by 5 degrees
In comparison to a stock cam. Maybe they have done this for the guys who do vanos deletes, I can't answer that question that would be one for the cam manuafter. Again, I am not saying it can be solved by tuning it thru the dme but, it would be a whole lot easier if we actually knew where the cams are positioned in relation to tdc. Without indexing the cams or putting a degree wheel on the engine your only hope it that the cams are made to exact tolerances every time and they are truly ground to the cam card specs. This is what we have found so I figured I would share it. Maybe I am too old school but if I had a dollar for every time I built and engine and put a degree wheel on it index that turned out to be off I could probably be in the Carribian right now under a palm tree with a beer.



Team TTFS

Hahahha well said. I can't agree more. I saw a lot of cams on big pushrod v8s from reputable companies off by at least 2 degrees sometimes more.. and sometimes each lobe is off by a different margin and we had to make an average and settle.. a degree wheel is the only way you can be sure of what valve timing will be like in relation to crank rotation.. I didn't have the luxury of degreeing my cams.. but I had a tuner a dyno and a long night of tuning hehehe. For now like you said a dyno tune is what we got.

[paulclaude]

Originally Posted by dafoe

Frank/TTFS is spot on here guys. It was my car, at the shop, with me, Frank, Stash1 and Austin (can't remember his forum user name), working with Frank most of the afternoon, and night until 2am...

On HIS dyno, not dynojet calibrated, my car did a base run at about 260ish whp (I was WAY wrong on the butt dyno!) and some GOD awful torque number like 230ish... Left with 340whp, and 278wtq. We found the cams were off by 8 degrees....

Dafoe, were both cams off, or just the inlet? 8 degrees timing netting 80whp sounds like a lot. Was it passing the Vanos test prior to this, or failing on inlet position reached? And what exactly was the fix?

Every set of these 288/280 cams i've worked with so far has required a negative DME offset to bring the camshaft around the zero adaptation range, rather than the retarded stock CSL value. It all sounds related to the same issue.

[TTFS]

Hey Paul,
It was 5 on the intake 3 on the exhaust. I set the adaptation to 2 degrees and worked back from there. In a perfect world I would have liked to set adaptation to 0 and park the cams but at that point you would need to get them closer mechanically, the play in the splines, chain ect and delay time between the cam sensor and the crank sensor won't let you get that close or at least I was not able to accomplish it. When I tried it went over the cliff so to speak so I settled for this approach.

[HassanEido]

Originally Posted by dafoe

Frank/TTFS is spot on here guys. It was my car, at the shop, with me, Frank, Stash1 and Austin (can't remember his forum user name), working with Frank most of the afternoon, and night until 2am...

On HIS dyno, not dynojet calibrated, my car did a base run at about 260ish whp (I was WAY wrong on the butt dyno!) and some GOD awful torque number like 230ish... Left with 340whp, and 278wtq. We found the cams were off by 8 degrees....

Oh man. That must've been a nurve wracking night but a great ending i guess. I can relate man, when I saw my baseline after the cams I needed to sit down . Regarding the butt dyno calibration , its why I laugh everytime someone installs a muffler or an intake and says it definatly pulls harder.. i suffered from miss calibrated butt dyno syndrome too. I thought the pulleys did quite well, when it was on the rollers it was next to no gains

[paulclaude]

Originally Posted by TTFS

Hey Paul,
It was 5 on the intake 3 on the exhaust. I set the adaptation to 2 degrees and worked back from there. In a perfect world I would have liked to set adaptation to 0 and park the cams but at that point you would need to get them closer mechanically, the play in the splines, chain ect and delay time between the cam sensor and the crank sensor won't let you get that close or at least I was not able to accomplish it. When I tried it went over the cliff so to speak so I settled for this approach.

I hear what you are saying - it does tend to be a fine line between exceeding the adaptation limit ('off the cliff') as you say, and getting things bang on the zero mark is a bit of a lottery. It's quite puzzling why they seem to have ground the cams like this - from what I can tell, 280/272's don't appear to have the same issues. But hey, at least the solution has been found using the correct approach. I've seen good results so far using the offset to correct things, as already mentioned

[.]

Wow a lot of new information here I've been digging for for months. Looks like I'm up against a lot more than I had imagined. Regarding the IAT's, I'm picking up a stock box from a friend today to hopefully try to get those down. With the head gasket, how much is .02 really going to knock down my compression? Half a point maybe? And this is before taking into account what was machined off the head right? Again what i gave for compression numbers was really just a guess from memory I'm not sure to be honest. But I did do the head gasket with intentions of future forced induction so I guess that's just something I'm going to have to live with until then. Will definitely get this thing on a dyno with Frank as soon as possible to get this sorted.

[gearhead55]

So now that the issue with cam timing is known is it possible for the TTFS guys to tune correctly remotely without tons of dyno time?

All this talk of hours on the dyno worries me. I'm out in California so would that mean strapping it to a dyno, datalogging a pull, sending that datalog over to TTFS, waiting a week, then getting on the dyno again for every trial and error change to cam timing?

I hope these 288/280s are worth the hassle...