Stroker # 2 - Finally Done...

[superstingray77]

Some of you guys may recall my Cam failure in my first 4.7. Caused by Titan engines shipping the head to me (pre-built ready to run) with the seat pressures so high it killed the cam in only 2000 miles.
The new one is done, installed, runs strong thus far.
505 Performance CNC ported head, LS valves, Proper springs pressure
Lunati Solid Cam .500/.525 lift 226/236 duration @.050
Trick Flow pushrods
Adjustable Roller Rockers from 505
JE Forged Pistons .060 over stroker slugs
4340 Forged I Beam Rods
ARP everything
Scat Crank
#27 injectors
Custom tune with SCT
AEM Air Fuel guage/controller
Bored TB
Banks header with heat wrap (Knockoff header so had to redo some of the tig welds on it due to poor QC you get what you pay for)
3" exhaust Dynomax
Intake port matched to head /gaskets matched
Fully spin balanced assembly

Hopefully my custom tune will show up today or tomorrow so i can see what this thing feels like with proper AFR and timing. It runs about 11.8 to 12:3 at mid to full throttle then gradually leans up to about 12:5 by 5000+ rpm, also tune will remove the factory rev limiter which this motor likes to hit very easily. Pulls like a freight train. Noticeable lump in the idle, going to lash the valves again this weekend which will make the cam more pronounced, i ran the lash loose at .030/.030 until the break-in period was done. So this weekend it comes down to .018/.018

http://www.youtube.com/watch?v=mkPoNE0rfQw

[Cheromaniac]

Yeah it does sound lumpy at idle but that's down to the cam's long duration. That 4.7L donk should rip on the dyno.

[superstingray77]

Yep i cant wait to lash the valves at .018 now that its broken in, typically every .002-.003 of lash will translate to about 3-4 deg additional duration on the valve so tightening up the lash will bring the full lift/duration of the cam into play. Its too smooth right now!!! I had to resist the urge though to use a 284 .555/.575 lift when I built it. Would have been to hot for daily driver. This one should lump up a lot once the lash is set, then i should really hear and feel it. As it is though it has good low end torque even at 1500 so hoping it wont weaken that too much as the increase in duration / lift will bring the power band up 3-400 RPM. Ill be happy if its fat and flat from 2000-6800.

[superstingray77]

Wow got the valves lashed and the cam is seriously evil sounding . Love it. Funny how nice these sixers sound cammed up and built.
Still waiting on my tune to show up had hoped it would have come Friday. My AFR is now 10:1 (horribly rich) at idle. From what I can tell the PCM gives up trying to correct and switches to open loop on the scanner, at open loop there is no compensation for the larger injectors and it just peggs full rich. This creates a nasty lean off idle stumble when the closed loop mode kicks back in as you step on it, hesitates,leans out to 18:1 or more then gradually comes back to stoich then under load say 1/3 to 1/2 throttle its about 11.5 to 11:8. Ugh... need the damned tuner. Anyhow can anyone explain why it hits open loop at idle? MAP signal from the monster cam?
Check out the video....

http://www.youtube.com/watch?v=rb_qu9guAWU

[CobraMarty]

Who's doing your tune? What is your vacuum at idle, lobe separation? Usually 'lumpy' cams and MAP/speed density systems don't mix well.

[SilverXJ]

Keep us updated on the tune. I'd be interested if the PCM can be made to play well with that. Your injectors may be too large as well. Usually the PCM has trouble with around 27lb injectors. I'd be interested to see what the AFR does if you threw the stock injectors back in, just to experiment.

[CobraMarty]

What year that you can tune with the SCT?

[superstingray77]

Its a 99 model wj 4x4. 505 perf is doing the program. Since my afr was hitting open loop at idle due to the cam and I wanted to drive it until the tune shows up iinstalled m home brew map adjuster. Set to 3.92v now idling in the 14.5range stumble is gone afr ia about 14.8on the.road but too lean whem you open it up. Like 16.0:1. Ill post cam card in a bit.

[Cheromaniac]

Since my afr was hitting open loop at idle due to the cam and I wanted to drive it until the tune shows up iinstalled m home brew map adjuster. Set to 3.92v now idling in the 14.5range stumble is gone afr ia about 14.8on the.road but too lean whem you open it up. Like 16.0:1.

Just richen it up until your AFR is near 13:1 at WOT. The O2 sensor feedback should keep the AFR near 14.7 at idle/cruise unless your injector size is way off.

[superstingray77]

Ill give it a shot this evening. For now I just wanted to drive it until the tuner shows up. The SCT should arrive in the next day or 2 or my patients will run out. 505 has had over a week to get the tune done and I paid for the product 3 months ago. I just gave them all the data they needed last Monday.
Many said the MAP adjuster wouldnt work on a DIS OBDII WJ but mine worked wonders. It wouldnt even stay in closed loop at idle until i backed the MAP voltages down. Now it idles right on the money and sounds great. Drives strong at very light / mid throttle openenings but running 15.5-16:1 I am taking easy on it. No lean pops or anything nor any detonation that I could detect by ear. Running cool, but lean is lean and dont want to torch a piston. Thanks for the help man!

[superstingray77]

Cam info: Lunati
114 LSA
110 centerline = 4 deg advanced (assuming installed straight up)
intake duration 236 Exhaust 241 @.050
Lift intake .492 Exhaust .508

Naturally I degreed it at 110 so the cam is 4 deg advanced.
Solid Flat tappet:
Lash is .018/.018 cold could likely tighten up some more as the iron head should expand approx .006/.008 my hot lash checks at about .022 Lunati says I could run .018 hot but im breaking it in easy. Once i tune it in i might experiment with tighter lashes to see where the power curve feels the best on the street.

[superstingray77]

Got the first 2 tune files on still running a bit rich on the idle, part throttle so were tailoring the file some more today for the idle/cruise. Power is amazing pulled hard in 2nd to 6200 with afr around 12.8-13.0. Engine had still not peaked but didnt figure my stock 42re for 6800 RPM shift points, and with stock gearing and slight larger tires I was crossing into the triple digit mark in 2nd. Thinking i could use lower gears anyone??? 3.73 is what is supposed to be in there front and rear, i have a feeling that after an accident they changed the rear end out and may have put in a 3.55 back in it. (4 whl binds unless on loose sand) Next up D44 with 4:56 gears front and rear.

[CobraMarty]

Cam info: Lunati
intake duration 236 Exhaust 241 @.050

That's a big cam. What is your idle vacuum?

[superstingray77]

I have a shop vac connected to the brakes running from the passenger seat using an AC power inverter. I just turn it on when i need to stop in hurry

Ill put a gauge on it tonight, its raspy lumpy evil idle though sounds awesome. Hardly feel the shimmy in the truck even with it in gear and AC loaded up. Trick was getting the AFR around 14:1 and commanding open loop for idle. closed loop will go insane on a cam this size due to the overlap and unburnt fuel etc hitting the 02 sensors. In closed loop it would cycle from 14-16 wildly while idling. Ran fine but now I have it locked it at around 14:1.

I want to say i was pulling about 12-13hg when I last checked it. Getting the AFR and idle timing right makes all the difference. No stalls no hesitation, just rips away from everyone at will.
I never thought a sixer could sound this mean. Makes killer torque from 2000 up, has no issues pulling along in traffic in OD at 1500 RPM. The added cubes helped there, and compression, porting etc. It pulls like my BMW M does up into the 6200-6300 range.. it wasnt done yet but I let off it.

[merdock69]

How were you able to command open loop on idle?