Swapping in another cam....

[BC847]

I've a local fire dept member who's got 1st dibs, else, fellow forum member The_Head has 2nd dibs.

I've got to get some pics of it (wear-patterns, etc) for myself and Zach.

You can give my 2nd dibs to Tater as I can't really afford it right now.

Oh well, that fire-fighter's gonna go for it anyway he says. (Call it Sold).

[BC847]

60# boost, 1400*F max on #2 only with regular street timing (Uphill, rolling into WOT, in overdrive, from 35mph to 75mph). Might be a little peppier.

[oldestof11]

See what the track times say.

Do you have a drive pressure gauge? From what I am reading on CompD, it gives higher DP and if you don't have enough flow, it chokes it out.

[dazedandconfused]

I don't think you're going to notice a huge gain since the other cam was pretty close to this one.

[BC847]

See what the track times say.

Do you have a drive pressure gauge? From what I am reading on CompD, it gives higher DP and if you don't have enough flow, it chokes it out.

Yeah, I would have gone to the track tonight but I also want to go to the beach tomorrow. If I break it tonight, I can't go to the beach. Besides, I had to reset the valve-lash and change the oil tonight.
I do have a DP gauge. Not so much an actual gauge, I've just got to put the sensor back in the manifold (part of the IISPRO Performax DATA logger. I can read the DP, interstage boost, etc in the log). Ill get to it eventually tuning stuff in. After redoing the valves tonight and taking it around the block, the 60psig boost, 1400*F EGT, remains constant. IIRC, those numbers are consistent with those of the prior cam on fuel only.

At this point, I've yet to turn on the W/M and energize the KSB. No boosted launches, etc. Just letting things settle in a little considering that row of head-studs had to come loose and be retorqued, etc.

I don't think you're going to notice a huge gain since the other cam was pretty close to this one.

I don't expect to. I'm more interested in the apparent shift of power to the left on a dyno-plot. Going into the swap, my WOT exhaust was a heavy grey. NOT black. My cyphering is that the apparent shift to the left is basically air coming on earlier in the RPM band which should prove convenient what with the VE's low RPM fueling and all.

I sure hope it works out that way.

[93flatbed]

I may have skipped over you saying, but are you running 24 valve tappets? And method for cam gear swap at home?

[BC847]

I may have skipped over you saying, but are you running 24 valve tappets? And method for cam gear swap at home?

Yes, new 24v lifters.

- Press the gear off the old cam.
- Heat gear in oven to 250*F ~ 300*F (and NOT over 350*F) for 45 minutes. (Make damned sure you clean the gear well so as NOT to stink-up Momma's kitchen).
- While gear is heating, clean cam snout of any burrs and lubricate with assembly lube.
- Install cam key with it's leading edge a little low so as to aid the gear sliding on.
- Carefully, with the side of the cam with the timing letters up, hold the gear over the cam snout aligning the keyway with the installed key, drop the gear onto the cam snout ensuring the key isn't pushed out. It doesn't hurt to have a brass maul handy to make sure the gear is fully seated on the snout. Tapping the gear home, you'll hear the "Ring" change as the gear cools and sucks-up to the cam snout.
- Spray your favorite lubricant on everything so as not to rust.

[BC847]

Driving to and from the beach was uneventful. Fuel mileage doesn't appear to be altered. The engine might be a bit more responsive in the lower RPMs. Definitely jumps with the turbos spooled. I'm waiting for the rains to hold off on a Thursday night so I can make a few passes at the local track to see what it's good for.
With work lately, I've not really had anything left at the end of the day to mess with it much.

[ahale2772]

I think Zach really nailed it on the head when he said that the most noticeable differences people will see are on heavily overfueled trucks... maybe it will allow a tad more fuel?

[BC847]

Yeah, I'm not over-fueled at this point. Running the 181/210 (1st gen) at WOT with the girls at full-song, W/M, full injection advance, the exhaust was a heavy grey. EGTs were 1500*f for sure holding it. At the top of the 8th, EGTs were 1600*f.

Now, the exhaust is decidedly lighter grey with EGTs down to around 1400* or so (in a WOT 1st through 3rd blast). Boost appears to have dropped from 60ish to 55ish.

Dicking around on back roads, bringing the boost up to 10psig or so then hammering it from a stop, it seems to come alive a bit earlier. On that note, it seems to be more responsive with regular driving (and getting on it).

Hope it doesn't rain this Thursday and isn't too warm at the track. I'll be able to get some better comparisons.

[Tacoclaw]

Sweeeeeet.

My truck has a lot more pep right off idle as well, it's pretty nice.

[oldestof11]

Do you still need the W/M with the new cam?

[BC847]

For the extra kick, sure.

I run a 50/50 mix so there's no cooling effect to be had.

[BC847]

OK, so changing the cam, 24v lifters, engine oil and filter, nothing else . . . . then taking it to the track .. . .

- It appears this cam is a little slower in spooling the turbos at the line.
- Holding the brakes and coming up to 2000 or so engine RPM has the turbos seemingly much more touchy at holding the launch-boost to 20psig. It wants to overshoot the boost and pushes the truck through the brakes.
- The torque definitely comes on earlier as I'm now having big problems with the tires getting loose out of the hole when the turbos go to full song. (The track conditions sucked so that didn't help). I really would rather not have to run slicks.

First pass, then the next, etc . . .

8.52 (2.00 60'). Not spooled proper.
8.32 (1.80 60'). Not spooled proper.
8.26 (1.89 60'). Blew the tires loose and had to get off it.
8.09 (1.77 60'). Still shuddered the tires, see vid below . .

http://www.youtube.com/watch?v=YnhA1yJ-Gzo

I'm having to relearn how to launch the thing.

[oldestof11]

Nice!

Can/did you try to leave with less boost?

Otherwise, I would look into Caltracs to help fine tune the suspension.