Big Cam=Poor choice= poor result.
Thread Starter
Teching In
Joined: Mar 2007
Posts: 41
Likes: 0
From: West Australia
Im not real bothered with its HP output more its bucking down low and driveability. After 2000rpm its smooth sailing. So far it seems the only way to lose the surging and pick up the low down is to fit a smaller cam. the dip around 3500-4000 isnt even noticeable on the road.
Im not real bothered with its HP output more its bucking down low and driveability. After 2000rpm its smooth sailing. So far it seems the only way to lose the surging and pick up the low down is to fit a smaller cam. the dip around 3500-4000 isnt even noticeable on the road.
The concern isn't that the dip isn't noticable. The concern is whether or not the dip is caused by a lean condition in the A/F mix during wide open throttle. If this is the case, your engine will like it much less than you do. Those type of dips are often caused by the knock sensors pulling timing due to a lean A/F mix. If it were my engine, I'd surely want it evaluated + there's the benefit of more "under the curve" power.
Thread Starter
Teching In
Joined: Mar 2007
Posts: 41
Likes: 0
From: West Australia
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
You say it is a dog down low, retarding the cam will not do anything but make that worse.
Did you degree the cam in your motor?
Your issues are purely tuning unless you have a mechanical issue, like intake leak, sticky TB sensor, faulty cam sensor etc...
Did you degree the cam in your motor?
Your issues are purely tuning unless you have a mechanical issue, like intake leak, sticky TB sensor, faulty cam sensor etc...
Thread Starter
Teching In
Joined: Mar 2007
Posts: 41
Likes: 0
From: West Australia
Its got an adjustable set , but just what do I adjust it to? I have sent a request off to Patrick G to have a new more street friendly cam spec'd up, I think I was a bit over zealous in going for a cam of this size.
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Although I am curious how this turns out for you!
R32WA, that doesn't sound right at all... not sure what your issue is, but just to compare...
I've got a 364c.i., with a 224/224 .581 114lsa cam, and AFR 205cc heads, BBK LT's, BBK ORY, BBK IM, BBK TB...
this was also tuned on a Dyno Dynamics and I made 446rwhp/416rwtq
I've got a 364c.i., with a 224/224 .581 114lsa cam, and AFR 205cc heads, BBK LT's, BBK ORY, BBK IM, BBK TB...
this was also tuned on a Dyno Dynamics and I made 446rwhp/416rwtq
I think you need to open it up and make SURE the cam is timed correctly with a degree wheel. then go through everything else in the valvetrain with a fine tooth comb.
who assembled your engine and who ground the cam for you?
On The Tree
Joined: Oct 2003
Posts: 150
Likes: 0
From: harrisburg PA
It's not the cam... And I would be curious of your super dooper aussie tuner. Not to throw stones...but things are different on the south side of the planet.
I just finished a 264/270 @ .050 - .714/.744 108 ICL / 112 LS cam combo for a school teacher. This is on a 346" shortblock with very big heads. I can't get him to stop driving it!!!
Get someone to tune it properly! Or find the vac. leak!
I just finished a 264/270 @ .050 - .714/.744 108 ICL / 112 LS cam combo for a school teacher. This is on a 346" shortblock with very big heads. I can't get him to stop driving it!!!
Get someone to tune it properly! Or find the vac. leak!
I concur, I bet it's running on 7. I put a motor together not long ago, a budget 346 with a lazy-lobe 240/244-110+2 and it idles fine, lopey, but with little rocking, and it pulls fine from well below 2000rpm without surging. Made nearly 500rw, too. And that's a 346! A properly running 383 WILL behave more mildly with a similar cam.
Just the bit where he said it rocks around badly when idling to me is the most profound evidence - a 383 with that cam should have a mild lope, but it should NOT shake badly. If it shakes as badly as he claims, it's either idling at 500rpm or it's down a cylinder!
Just the bit where he said it rocks around badly when idling to me is the most profound evidence - a 383 with that cam should have a mild lope, but it should NOT shake badly. If it shakes as badly as he claims, it's either idling at 500rpm or it's down a cylinder!
Last edited by drz; Apr 10, 2008 at 10:53 PM.
Man I am running a motor almost identical to yours in every way except it is 347 cubic inches. My cam is very similar as far as duration it is 239/242 spec'd out and ground by Allan Futral. Mine runs and drives great. Heres what you need to do before WASTING money on a new cam...
-Degree your cam and get that bastard set right (because I would bet money that it isn't!)
-If that doesn't help go over your valvetrain with a fine tooth comb and your ignition system
-If that doesn't resolve the issue FIND A NEW TUNER!
-Degree your cam and get that bastard set right (because I would bet money that it isn't!)
-If that doesn't help go over your valvetrain with a fine tooth comb and your ignition system
-If that doesn't resolve the issue FIND A NEW TUNER!
The concern isn't that the dip isn't noticable. The concern is whether or not the dip is caused by a lean condition in the A/F mix during wide open throttle. If this is the case, your engine will like it much less than you do. Those type of dips are often caused by the knock sensors pulling timing due to a lean A/F mix. If it were my engine, I'd surely want it evaluated + there's the benefit of more "under the curve" power.
TECH Enthusiast
Joined: Apr 2007
Posts: 629
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From: Charlotte, NC
See this thread for a prime example:
https://ls1tech.com/forums/showthrea...824&highlight=
I've had my car on a DD and it made more than it did on a dynoject, BUT the shop already had some crazy +14% figure added to it to make it "READ" like local dynojets.