Big Cam=Poor choice= poor result.
Do you remember what the duty cycle of injectors were doing or where they were at? If it was "missing" it would throw a code. Sounds like it could be down on fuel. For example we did a 346 with cam that should make 360-370rwhp but with a bad MAF cause fuel delivery problem duty cycles were crazy and the first dyno pull was 234rwhp, after 9 more pulls below 300rwhp changed the MAF, tuned the tables then first pull went 350rwhp. Just sharing my mishap with you. The MAF caused us 100+rwhp, so fuel delivery could be a problem, a good tuner should be able to tell you if he knows what he is looking at it should b obvious at WOT by looking at duty cycles, o2's, and wideband o2.
Thread Starter
Teching In
Joined: Mar 2007
Posts: 41
Likes: 0
From: West Australia
Dan said it was over cammed and thats what causes the low down surging due to the intake reversion, Ive been over it, it runs on all eight, valve train is all up to spec and there isnt any other tuner that I'd trust to tune it, I have a new cam on the way courtesy of Patrick so I'll slide that in and it should be happy days with more low down to boot.
Launching!
Joined: Apr 2008
Posts: 245
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I dont think your over cammed. I had a 240/244 112+4 LSA in a stock cube LS2 and allthough the bottom end was a little rough it screemed on the top. I didnt read the whole thread but did you change the maf to a larger one? Is it tuned speed density?
I think the computer is trying to adjust but the maf cant keep up with the needs of the motor.
I think the computer is trying to adjust but the maf cant keep up with the needs of the motor.
Thread Starter
Teching In
Joined: Mar 2007
Posts: 41
Likes: 0
From: West Australia
its got no maf tuned in speed density, it pulls like a train up top and screams to the limiter but below 2k rpm its a pig to drive and I do a bit of traffic driving so I cant have a pig.
well one thing I dont think people have brought up is that everyones opinion on low engine speed driveability will be different. what feels like a flat low rpm power band could feel totally normal to me. I agree forget about the HP #, take it to the track and see the ET'S and more importantly the trap speed.
but it IS very possible the cam is retarded already and could be causing no torque down low but would feel fine in the mid/upper rpms. same for a vacuum leak. Ive heard of people not getting something right on the assembly of the fast intake and having internal vacuum leaks.
all that said, Im goin to agree with everyone else here, that cam should not be that hard to tune in a 383. might not have the characteristics you like, since you mentioned its a driver that sits in traffic all day long, but should be smooth reving, even from idle. with a very noticible lope to it at idle.
who installed the cam? if your tuner did it, then he should know how to degree a cam right? you mentioned you bought the adj. timing chain, but never responded to anyone asking if the cam has been degreed in, to make sure all the parts are 1 installed correctly, 2 the parts are machined correctly. wouldnt be very uncommon for it to be a couple degrees off, with some bad ones as much as 4 of 5 degree's off. sometimes it could be the cam, it could be the timing chain, or it could be a tooth off during the assembly.
if you do end up swapping cams, let us know how it all goes.
chris
but it IS very possible the cam is retarded already and could be causing no torque down low but would feel fine in the mid/upper rpms. same for a vacuum leak. Ive heard of people not getting something right on the assembly of the fast intake and having internal vacuum leaks.
all that said, Im goin to agree with everyone else here, that cam should not be that hard to tune in a 383. might not have the characteristics you like, since you mentioned its a driver that sits in traffic all day long, but should be smooth reving, even from idle. with a very noticible lope to it at idle.
who installed the cam? if your tuner did it, then he should know how to degree a cam right? you mentioned you bought the adj. timing chain, but never responded to anyone asking if the cam has been degreed in, to make sure all the parts are 1 installed correctly, 2 the parts are machined correctly. wouldnt be very uncommon for it to be a couple degrees off, with some bad ones as much as 4 of 5 degree's off. sometimes it could be the cam, it could be the timing chain, or it could be a tooth off during the assembly.
if you do end up swapping cams, let us know how it all goes.
chris
