I have been thinking about ditching my LE2 cam partly because i need a really mild cam with perfect street manners and little to no tuning. been searching and looking around the B-body forums and i've been considering the 227 or gm846 but i want to know how well they work with nitrous. i know FrankZ ran low 11's with the 227 so its a proven performer, and i like the gm846 as well. if the cam will make at least 330 and a really flat torque curve, then i say with a 175-200 shot it will go deep into the 11's for sure. im considering the swap sometime this month or late next month. really need my car running perfect cuz im going back to school.

dont get me wrong the LE2 cam is sweet but i've been having tuning issues since day one, and the only way to fix it is a dynotune. well the nearest place to get it done is 4-5 hrs away and then $400+ for the tuning, cost for trip, need a flat bed, and i dont have anytime during the week cuz i work 9-5.

 

What kind of issues are you having? Whats the compression on that new motor?

A smaller cam would only make my problems worse,,,,

 

impala gaskets, pistons .10 in the hole, heads decked .010, and i believe the compression is 11.5-11.8. well the cam has a lot of overlap and the ECM thinks its going lean, and dumping the fuel. i have a small issue at 2k rpm but i think the tuning is way off cuz in the morning when i start the car i leave 2 black spots on the driveway. my eyes get all watery if i stand behind the car cuz its running rich. i get several codes one being MAP sensor low vacuum, and the others are lean condition bank 2. SES always comes on after a WOT run but seems to pull hard all through the RPM, part throttle tuning is a major problem cuz i cant get my foot off the gas at a stop. I know that a smaller cam will need a mail order tune at most to run perfect, as supposed to a dynotune for my setup and i might need a new fuel system as well. kinda confused about what i want to do, just need my car to run perfect.

 

Your compression is a lot lower than mine, so thats no worry.

So its trying to die as you come to a stop? And map sensor codes...

If you want to try something new, here is what I have done on my 2 motors with 847 or bigger cams in them. You can try to drill the throttle body.

There is a tiny hole between the two throttle blades. Its never effected by the IAC. Find a bit thats just a little bit bigger than the hole, say 25% bigger and open it up.

Some people dont like this method, but it has helped every big cam car I have worked on. They stop easier, idle better, start easier. Only down side is if you go too big the throttle will stick until the IAC can make up for the difference.

I think the IAC is unable to open big enough to allow a big cam/heads car to breathe when the throttle is closed.

Just a thought though

 

how big does that hole need to be drilled? if i put the car in Neutral when im comming to a stop it has no prob's, then throw it back in drive when the light goes green. I dont know how much tuning this thing needs, but i'll give it one last try before i swap it out. im getting a obdI cable so i can get some datalogging then email Alvin@PCMforLess see if he can fix it, if its still no go then im getting another cam.

 

I think you are having other problems besides the camshaft. Who did your mail order tune, or do you even have one? A mail order tune should have that thing driving NICELY, IF all your other stuff is in order.

EDIT: Oh yeah, if your SCR is 11.5-11.8, I'd be very careful how small of a cam I put in there. Might drive your DCR through the roof.

 

Do you at least have a mail order tune?

Marshall is right in saying your compression ratio might be a little too hight for such a small cam.

 

I have a mailorder tune from Alvin@PCMforLess, and boy did that make a night and day difference from my old tune for the xe230/236. the idled way better and before you really had to get on the gas or the car would die. I still have problems with this but its a little more managable. somtimes if the rpm's go too low like when im reversing and turning at the same time the car will just start surging like it wants to die. with the gas pedal slammed down it will just sputter for like 10 seconds and then all of a sudden its fine again as long as the pedal is nailed, or it will die and an SES light comes on. usually its a MAP code for low vacuum, but ive replaced every sensor on the damn engine so i have ruled them out. i guess the cam is too big and needs some fine tuning through a wideband to catch every problem area.

3 opti's, 4 coils, 2 ICM's, 3 sets of wire, 7 sets of plugs TR55/TR6/AC delco platinums, Knock sensor, MAP sensor, coolant temp sensor, IAT, and a partridge on a pear tree...LOL!!! that rules all those out, and no one can help me tune/datalog because no one runs LT1's down here everyone got on the LS1 bandwagon .

since im running impala gaskets then i can just go with a thicker one to drop my SCR to 10.9 or so. how small of a cam can i go with before the cr becomes a problem.

 

I'm running a small solid roller in my 381. The idea was to build a very streetable engine that would pass NJ rolling emissions, but be stout enough to support a 300-shot of nitrous at over 7,000rpm. Cam specs are 230/242 114LSA 0.590/0.590. Street friendly, used to pass emissions (haven't bothered to try in the last few years), even got decent mileage when it was street driven. SCR is 10.8:1. You give up some peak HP with the 114 LSA, but it uses the nitrous very effectively.

 

My 846 loved nitrous....