Hot cam with turbocharger??
Hot cam with turbocharger?? I have a turbocharged z28 with the lt4 hot cam. Everything is basically stock internal wise execpt for the hot cam. I was wondering how much more horsepower would I see if I replaced the hot cam with a turbocharged cam. 20rwhp?? or more. I already have the hot cam in the car and this past summer had a turbo put on. I think the cam is defently robbing some power - Does anybody know how much I should expect with the right cam - just cam only - Mike
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what makes you think the cam is robbing power, unless you are refering to its duration and lift, in which case yes, you would make more power with a little more lift, and duration.
how much boost are you running? and do you have any numbers (dyno, or track)?
how much boost are you running? and do you have any numbers (dyno, or track)?
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Originally Posted by FIREHAWK#608
Not only the duration and lift, but the 112 LSA is bleeding off boost.
Get something on a 115... but then again, you knew that was coming.
Get something on a 115... but then again, you knew that was coming.
Its a big cam..
I am looking at running a comp 206/212 on 112 but that little of duration has no overlap.
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First of all, a turbo does not "bleed off boost". With more exhaust pressure than intake pressure (99% of turbo's), you actually force exhaust into the intake port during overlap, not the other way around.
That said, the HOT cam has -1 deg of overlap at .050". The cam that I'm running with my turbo set up has +2 deg of overlap at .050". I've seen successful turbo cams with anywhere from -8 deg overlap to +18 deg everlap, so I don't think your 112 LSA HOT cam has too much overlap.
That said, the more boost you run, the more specific-to-turbo's your cam needs to be. For instance, if you were running 2 psi boost with 4 psi backpressure, any ole' NA cam would be fine. However, if you're running 30 psi boost and 60 psi backpressure, the cam might look a little different. At only 5 psi, not enough has changed in the motor to require a specific turbo cam. For instance, compare these cams:
Your HOT cam:
218/228 - 112
Proven turbo cam for 355 cid and 22 psi boost:
218/218 - 114
Not too much different, eh?
Leave the cam alone. You won't gain more than 10 rwhp.
You should focus on improving other area's, like downpipe, intercooler, raise the boost, etc. . . I wouldn't bother changing the cam until you get in the 20+ psi range.
What kind of turbo is it, anyway?
That said, the HOT cam has -1 deg of overlap at .050". The cam that I'm running with my turbo set up has +2 deg of overlap at .050". I've seen successful turbo cams with anywhere from -8 deg overlap to +18 deg everlap, so I don't think your 112 LSA HOT cam has too much overlap.
That said, the more boost you run, the more specific-to-turbo's your cam needs to be. For instance, if you were running 2 psi boost with 4 psi backpressure, any ole' NA cam would be fine. However, if you're running 30 psi boost and 60 psi backpressure, the cam might look a little different. At only 5 psi, not enough has changed in the motor to require a specific turbo cam. For instance, compare these cams:
Your HOT cam:
218/228 - 112
Proven turbo cam for 355 cid and 22 psi boost:
218/218 - 114
Not too much different, eh?
Leave the cam alone. You won't gain more than 10 rwhp.
You should focus on improving other area's, like downpipe, intercooler, raise the boost, etc. . . I wouldn't bother changing the cam until you get in the 20+ psi range.
What kind of turbo is it, anyway?
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FormerVendor
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From: Australia
Not much is understood about turbocharger camshafts by most tuners. The reality is that what works in a normally aspirated engine is generally just as effective in a turbo application. We have several cars running our big single T1000 kit using camshafts as 'boost unfriendly' as 242/244 on 108 LSA with excellent results 
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I agree, Mr. Tuna. After almost 20 years, the Turbo Buick crowd still can't settle on what makes a good turbo cam. The following have all proven to make power:
192/196 - 106 (stock)
206/206 - 106
214/214 - 112
210/205 - 112
210/210 - 112
204/214 - 112
218/226 - 112
Not too many turbo Buick cams are on a 114 LSA. Also, note the lack of consistency.
192/196 - 106 (stock)
206/206 - 106
214/214 - 112
210/205 - 112
210/210 - 112
204/214 - 112
218/226 - 112
Not too many turbo Buick cams are on a 114 LSA. Also, note the lack of consistency.
FormerVendor
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From: Australia
We run the fastest radial tyred Skyline GTR outside of Japan (8.7 @ 163) over here in Aus, and after experimenting with numerous camshafts a combo of 280/272 @ 110 works the best
Too much LS1 cam theory is based on 1927 text books
Too much LS1 cam theory is based on 1927 text books
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Originally Posted by Street Tuna
8.7 @ 163. . . 280/272 @ 110 works the best
Tuna, at what lift is the 280/272 duration taken at?
Mike
You guys worry way too much about cams, stock ones work great. A cam is one of the last things I would worry about in a turbo car unless I was looking for every last bit of power.
My new 370 iron block motor is using a z06 cam.
My new 370 iron block motor is using a z06 cam.
Originally Posted by Street Tuna
Ported heads give very very little gain on a turbocharged LS1. So small in fact that you may not even be able to measure it....
Originally Posted by Street Tuna
Ported heads give very very little gain on a turbocharged LS1. So small in fact that you may not even be able to measure it....
Any data on this? More cfm at the same psi = more power.
FormerVendor
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From: Australia
6psi with a set of stock heads, 6psi with a set of big valve big cfm heads = scarily close to identical power levels. We have seen a handful of horsepower for $1000 plus worth of heads. Better to add a couple of psi and make another 50hp.....
I don't think a lot of lower boost setups will see much of a gain from ported heads.
If you are pushing a combo to make a lot of power, I'd really consider a set of aftermarket castings like ET Performance, AFR, or AllPro. Thicker deck means better clamping force.
If you are pushing a combo to make a lot of power, I'd really consider a set of aftermarket castings like ET Performance, AFR, or AllPro. Thicker deck means better clamping force.
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From: Boise Idaho
Originally Posted by Pro Stock John
I don't think a lot of lower boost setups will see much of a gain from ported heads.
If you are pushing a combo to make a lot of power, I'd really consider a set of aftermarket castings like ET Performance, AFR, or AllPro. Thicker deck means better clamping force.
If you are pushing a combo to make a lot of power, I'd really consider a set of aftermarket castings like ET Performance, AFR, or AllPro. Thicker deck means better clamping force.
I might think this is true on ls1's with great flowing stock heads, but on an lt1, lt4 you should see a noticable gain, not a great gain, but a noticable one.
