obdII vs. the stroking

[Spliffotticle]

Herro stroking com padres. I am starting a specific thread for strokers with FUNCTIONAL obdII. I'm not interested in piggy backs or carbs & dizzies. I'm a direct ignition lovin waste spark makin fuel injected O2 sensing kinda guy. Short of reprogramming, I would like to know who among you have stroked your obdII? Were mods necessary to trick or treat the computer? Did you retard or advance your cam and or sensor? Victory or defeat? I have so many bugs on this thing obdII may not even be my rival but I still want this info. Now, if you'll excuse me, I am going to see about blowing my budget stroker up

[YJason]

I'm running a 4.6 on a stock OBDII out of a 96 cherokee without any problems. 24lb injectors, 68-231-4 cam 62mm TB. I also have a autometer A/F guage and it runs near perfect on the A/F ratio. Every once in a while it will idle rough on start up but 3-4 seconds its idling perfectly.

[Spliffotticle]

Is your cam advanced?

[lafrad]

I run a '99 cherokee. stock injectors and no programmer. its a little Lean at WOT (not much tho, I kept the cam small), but the ODBII adaptives are 100% happy with the stroker, cam and header. no codes, and the plug-in smog check machine at the inspection station is happy with what it sees.

I have a Crower cam that I have setup straight up. (no advance or retard)

[YJason]

Is your cam advanced?

No, my A/F hits 12.3 at WOT.

[Spliffotticle]

Darn it man! My cam is advanced & I got one good tire ROASTING out of the engine and now I can not get it to do anything but fall on it's face unless I'm spinning a few grand (& even then it only has a narrow window before it acts like it's starving but I already know it isn't). I'm still having problems finding a good spot for the CPS. It doesn't adjust the spark timing the same way as a dizzy. I actually rigged up a timing light to my coil rail and found that it DOES change the spark timing.... but not gradually like a dizzy. In fact I have to discharge the ecu to get it to change after it has been recorded to be out of sync by so much for so long. I really like my DCR being almost 9.5 but I'm seeing that you all find that to be atrociously high and would recommend rocket fuel but I'm not convinced. I laid a 50' strip (& intermittent patches as the other side tried to limit slip) down as I drove it around the block on it's initial test drive. This tells me that my DCR was just fine then so I really want to keep my 9.4 and just solve the issue instead of giving up and settling for the 8s.

[lafrad]

I'm running: http://www.crower.com/products/camshaft ... 6-hdp.html with a 10.05:1 SCR. Installed straight up, the DCR is 8.4-ish... how the heck do you get a 9.5 DCR?!?!?!?

its a tiny cam... I was looking to gain torque by shorter durations, but keep a wider powerband by a decent LSA and NOT advancing it. works great, and it has no problem with 87/89 in the winter, and 89/91 in the summer.

[Spliffotticle]

I believe this is all in order...
bore: 3.935"
stroke: 3.895"
combustion chamber: 58cc
deck clearance:.0085"(decked .013")
gasket:.051"
gasket bore: 4"
dish: 13cc
connecting rod length: 5.875"
comp cam 68-115-4
duration 240*
angle of separation: 108*
displacement: 284.21ci (4.66l)
SCR: 10.33
DCR: 9.4
quench.05949
IVC angle: 44*

turbocharged running 91

[gradon]

You went off the stock 4.0 deck clearance of .0215" minus the .013" you had taken off to get your claimed .0085" deck clearance. You'd have .0085" clearance if it was still a 4.0 using the stock 4.0 crank and pistons, but since you are using a longer stroke crank, shorter 4.2 rods, and more than likely smaller-than-stock-pin-height pistons, your deck clearance before the .013" cut was actually around .040", not .0215". Your compression numbers will be less with the correction. What +.060" pistons did you use? I inputted the H802/825cp60s specs in the calculator and got .0765" quench and .0255" deck clearance with a 9.8:1SCR and 8.9:1DCR(you definitely don't want to advance the cam).

[Spliffotticle]

h802cp. of course I took off the teflon because forks and skillets don't mix and after 42 miles it's all in the oil filter anyway. TEFLON HAS NO PLACE IN ENGINES OR OIL. As for the dimensions of them I gots no clue. we have MEASURING POINT 2.30 FROM TOP OF HEAD; MINIMUM CLEARENCE .0010 (lmao it's actually spelled like that on the Sealed Power sticker) SKIRT SIZE 3.93375+/-0.00025 INCHES but I just realized these are the ones you used on the calculator. I have the cam back @ 0 & the thing (SO FAR) is incredible. I reset the computer & put everything back in it's place and went around the block breaking loose 31" thornbirds with ease. I figured out the trick was just don't slam the 100mm EXTRA BIG ASS THROTTLE open so fast. Now I'm having blow-off issues with the turbo though. lots of chatter coming out the inlet when I let off too fast.

[gradon]

I input the h802cp60's 1.592" pin height, so they were .0385" down the hole before the .013" cut and now are .0255" down the hole(assuming the deck height was in the middle of the spec). So 9.8scr and 8.9:1dcr(if your cam is straight up, more if advanced, less if retarded). You don't need to use the big font anymore--we'll start ignoring the throttle on the end. Good luck getting the sensors sorted. Also, what experience do you have with the teflon flaking on Sealed Power pistons? You think they go out of their way to add it for no good reason?

[Spliffotticle]

lol I will font any size I please. . . ... but it took me 10 minutes to decipher your clever joke so kudos

Also, what experience do you have with the teflon flaking on Sealed Power pistons? You think they go out of their way to add it for no good reason?

It certainly doesn't flake. It was a very well applied coat & I didn't mean to offend you. I'm sure you come from a very respectable background of piston coaters. The reason it doesn't belong in your engine is a comprehensive subject and I will be happy to assist you. This is a two-part series on the fluoropolymer polytetrafluoroethylene or PTFE.

A piston travels up and down in a bore with the intent of riding on a film of oil. You may notice that you have to change your oil. Why? Why doesn't your motor oil stay as clean as differential lube or transmission fluid? Because oil is burning in small amounts at your compression ring. There you will notice a marvelous transition where oil is converted to carbon and other fantabulous chemicals but the main culprit is carbon. as it works it's way past the pressure & oil rings it mocks your teflon because teflon is softer than carbon and silicon and when you mash it between two pieces of metal guess who wins?
PART II
Teflon in oil and or oil additives? good or bad?
bad. while teflon does in fact reduce friction, increasing overall horsepower, the IRON CONTENT of the used motor oil DOUBLES indicating engine wear has increased by 2x

[gradon]

Not offended, but you're the first person I've read of that purposefully removed the coating and wanted to know why. I guess if I ever have to take the head off and do a re-ring job I'll take a look at the skirts.

[Spliffotticle]

I was joking. I knew you weren't offended. I was just hoping to give ya a chuckle. But I personally feel that it is an unproven gimmick to add flare to a boring cast piston. I also rounded the edges on the underside so it would be harder to catch the cylinder wall with those bat-signal shaped skirts. I give the piston a "C" as far as cast pistons go. It was what I could afford though.

[gradon]

It's not as boring as others since it has silicon in it, thus the hypereutectic(H), and had coated skirts(C). You could've gotten regular old 677p without the silicon or coated skirts.