I currently am running Lloyds LE2 heads with a GM847 cam. I was curious if anyone else out there running either the GM847 or cc306 or similar could post reguarding their experiences with rpms below 3k. It seems as though my car is a slug below 3k rpm with this cam, I cant even think about stomping on the gas without having to slip the clutch if I am below 3k rpm, it doesnt matter in what gear. Before with my stock cam I could just hit the gas and the power was there, now with this cam it seems as though it is like a 10lb weight that needs to be turned, once the momentum kicks in then it really flies, but it takes a long time to get it there. Is this just a normal thing with such big cams?

I new it would be slugish, but this is worse than a saturn below 3krpm.

Has anyone done some kind of tuning changes to gain them power down low? I dont have anyone here capable of dyno tuning due to my location (Alaska) or else I would just be doing that.

 

Im guessing you atleast have a mail order tune or something besides the stock tune. I know though that my old cam didnt really get alot of power untill 2800 rpm or so...but i wouldn't have really called it a slug below that.

 

My car has more power down low than I thought it would. Without the MT street ET's I could spin my car to 100+ (sitting still of course). With the MT's I just got to replace my rearend since I broke 7 teeth off the ring gear.... http://img.photobucket.com/albums/v6...0/100_0797.jpg I still have a problem with traction at the track with the MT ET's and only manage a 1.7 60'. It would be 1.6 or probly even 1.5's with more suspenion mods. (coming soon). It's the top end I'm having problems with, it's not bad, just not as good as I hoped for. Of course I have an auto and 3200 stall so it's not exactly the same.

 

I have a mail order tune from Ion. Everything checks out ok with datamaster/freescan. I guess I was just hoping for more. I am going to be replacing my stock catback system thats after my hooker 3" Y pipe with a 3" in/out dynomax muffler/glasspack from thunder racing. Hopefully that will allow a lot more flow and fix some of my downlow struggle. I also get a lot of popping from unburnt fuel from time to time, like when deaccelerating or downshifting.

I filled up yesterday with 92 octane with 10 gallons and I got 140miles out of the tank. So I am getting 14mpg, mostly highway driving. So it seems decent gas milage for the amount of modification this motor has.

 

I got 9MPG last tank! I only use 93 octane. I average 11MPG. I will be tuning mine again with wideband tomorrow or the next day. I'll let you know how that turns out.

 

Thats why the 306 is not liked by many. Although its used a lot on the boards, i think it has a pretty good reputation of being very sluggish at lower rpm's and the power just drops after a certain rpm. Isnt this so?

 

Ive heard that both the 306 and 847 just keep climbing, not just drop off. The xe 230/236 i had just dropped off at 6200 and ive heard most xe cams do. Ill be going with the 306 and hope for better results.


Silvershark what gears are you running in your rear? I would recommend atleast 4.10s with an 847.

 

Ive looked into the 306 and the 847 and some pretty good cam guys are not very fond of these cams especially the 306. This is susposially an older type cam, but obviously does work. But from talking to people i would def go with a custom cam of that size before either of them cams.

 

A custom cam is always the best...im just going with a used 306 and stock heads while i save up for the le3. Most people said the bad things about these cams because the new xe cams were supposed to be so great but they are to aggressive imo and valve float is harder to control at high rpms, hence the fall on there face at 6200, but tha twas with cm612 springs that cm recommended.

Just ask Clint(t/a lt1) he has gone 11.24 with a 306 and some heads that were ported locally and 10.17 on a 200 shot. All this out of a 355 lt1 with ported stock casting heads is pretty good for a "old" cam.

 

I have the stock 3.43 gears in the rear. I think perhaps my exhaust is just bottlenecking me down so much that I am not gettting the power I should.

 

Ya stock exhaust would definetly hurt you, you do have headers dont you? And some 4.10s would definetly help the car from being a slug.