Cam Swap - Lost 80 hp and have lots of issues
05-23-2008, 07:13 PM
#1
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Join Date: May 2008
Posts: 13
Cam Swap - Lost 80 hp and have lots of issues
I have recently switched from a solid roller setup to a hydraulic roller setup. A lifter went bad, and killed my cam, so i have changed out the whole valvetrain with the following:
cc rockers: 1.6
cc hydraulic roller cam: 584/575 242/248@.50 duration
cc pushrods
cc beehive valvesprings
my current setup is as follows:
396ci stroked
lt4 stage 3 heads
58mm throttle body
4.10 gears
255 lph fuel pump
electric water pump
random technology cats
b&b tri-flo exhaust
custom tune
i changed out spark plug wires and spark plugs (msd wires, ngk plugs), air filter, had a custom tune put on it. right now i'm down from 456rwhp to 382rwhp, and my car will intermittently die when coming to a stop or at idle. occasionally upon startup, it will idle at .5 very rough, but will start idling hire as the car runs longer.
my maf sensor is not connected - not sure if it ever was though. the car was tuned around that though. the cam has been degreed, and the valves have been adjusted.
any comments / suggestions will be greatly appreciated.
cc rockers: 1.6
cc hydraulic roller cam: 584/575 242/248@.50 duration
cc pushrods
cc beehive valvesprings
my current setup is as follows:
396ci stroked
lt4 stage 3 heads
58mm throttle body
4.10 gears
255 lph fuel pump
electric water pump
random technology cats
b&b tri-flo exhaust
custom tune
i changed out spark plug wires and spark plugs (msd wires, ngk plugs), air filter, had a custom tune put on it. right now i'm down from 456rwhp to 382rwhp, and my car will intermittently die when coming to a stop or at idle. occasionally upon startup, it will idle at .5 very rough, but will start idling hire as the car runs longer.
my maf sensor is not connected - not sure if it ever was though. the car was tuned around that though. the cam has been degreed, and the valves have been adjusted.
any comments / suggestions will be greatly appreciated.
05-23-2008, 08:14 PM
#3
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Join Date: Jul 2002
Location: Phoenix, AZ
Posts: 1,277
Could you show us the dyno graph? That would help.
What does ".5" mean?
What was your cam before and was the TB adjusted for that particular cam? Sounds like you need to adjust the TB for (I assume) a larger cam.
What does it mean to have a custom tune? Are you sure of the timing and the AFR at WOT?
What does ".5" mean?
What was your cam before and was the TB adjusted for that particular cam? Sounds like you need to adjust the TB for (I assume) a larger cam.
What does it mean to have a custom tune? Are you sure of the timing and the AFR at WOT?
05-23-2008, 08:25 PM
#4
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Join Date: May 2008
Posts: 13
the beehive springs are cc# 26918-16. the specs are as follows:
od: top 1.055" bottom 1.29"
ID: Top .650 bottom .885
Seat pressure: 130lbs @ 1.800"
open pressure: 333 lbs @ 1.150"
Coil Bind: 1.140"
Spring Rate: 313 lbs/in
The cam lobes are:
lobe lift: .3660 / .3630
lobe seperation: 113.0
od: top 1.055" bottom 1.29"
ID: Top .650 bottom .885
Seat pressure: 130lbs @ 1.800"
open pressure: 333 lbs @ 1.150"
Coil Bind: 1.140"
Spring Rate: 313 lbs/in
The cam lobes are:
lobe lift: .3660 / .3630
lobe seperation: 113.0
05-23-2008, 08:37 PM
#6
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Join Date: Apr 2008
Location: Orlando, FL
Posts: 80
waiting for the graph 
The stage 3 LT4's, what size valves are in the heads? The 918's are great springs, but not sure if they are up to the task for that cam (depending on the valve size) if it's a 2.05" intake valve that might be your prob. What are they installed at 1.800"?
The stage 3 LT4's, what size valves are in the heads? The 918's are great springs, but not sure if they are up to the task for that cam (depending on the valve size) if it's a 2.05" intake valve that might be your prob. What are they installed at 1.800"?
05-23-2008, 08:40 PM
#7
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Join Date: May 2008
Posts: 13
http://s129.photobucket.com/albums/p...ent=hydcam.jpg
http://s129.photobucket.com/albums/p...t=solidcam.jpg
http://s129.photobucket.com/albums/p...rent=dyno1.jpg
Here are the links to the old and new cam, along with the dyno sheet.
http://s129.photobucket.com/albums/p...t=solidcam.jpg
http://s129.photobucket.com/albums/p...rent=dyno1.jpg
Here are the links to the old and new cam, along with the dyno sheet.
05-23-2008, 09:06 PM
#9
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Join Date: May 2008
Posts: 13
the car was surging and idleing very low (.5) after the swap - i took it to a shop that tuned it using lt1edit. the WOT was not open all the way the first time i took it to the shop, but i took it back to have them see if they could figure out what was going on, and they noticed that WOT was not open all the way so it was adjusted. this ended up getting me from 360 to 382hp.
and sorry to say, but i put a smaller cam in...
and sorry to say, but i put a smaller cam in...
05-23-2008, 09:13 PM
#10
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Join Date: May 2008
Posts: 13
one more thing i forgot to add -
my gas mileage sucks *** now - with the solid i'd average about 12-14 in town and 22-24 on highway. since the swap, i'm getting 8 freaking mpg. i checked my fuel pressure and it's reading at 36psi.
my gas mileage sucks *** now - with the solid i'd average about 12-14 in town and 22-24 on highway. since the swap, i'm getting 8 freaking mpg. i checked my fuel pressure and it's reading at 36psi.
05-23-2008, 09:17 PM
#11
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Join Date: Apr 2008
Location: Orlando, FL
Posts: 80
You have some issues a little after 6k for sure, but it looks like power is leveling off around there anyways. I had a feeling it would be the 292XFI, that cam has made great power before with other set ups, What exactly was changed from the cam swap? The 918 springs are lookin like they arent enough although I don't know how much that will really help out. On the cam card it says springs recommended are 26986-16's? Thats CRAZY lol, no way would those springs hold that camshaft above 5800 RPM. I would say possibly the K-800 K motion spring or go through the tune very carefully and see what is going on. Obviously something is wrong here, but not sure what's up. What lifters are you running now?
05-23-2008, 09:26 PM
#12
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Join Date: May 2008
Posts: 13
the lifters are cca-850-16. sorry, i should have listed that earlier.
i plugged up my laptop and got readings using datamaster - i'm not sure the best way to post that file though.
i'm new to the whole tuning thing. i'm considering purchasing a copy of lt1edit - i pulled the tune off the pcm using pcmread, but dont have a way to view it, or i'm not sure of a way to view it...
i plugged up my laptop and got readings using datamaster - i'm not sure the best way to post that file though.
i'm new to the whole tuning thing. i'm considering purchasing a copy of lt1edit - i pulled the tune off the pcm using pcmread, but dont have a way to view it, or i'm not sure of a way to view it...
05-23-2008, 09:51 PM
#14
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Join Date: Apr 2008
Location: Orlando, FL
Posts: 80
The 850's aren't the best lifter, but i'm sure they can handle the task. Hmm, i'm not very good at explaining how to upload files, if you do it, send it to me in an email and i'll have my tuner go over it and see what he thinks.