cam in my blown 383?
06-29-2013, 11:20 AM
#1
cam in my blown 383?
Ok so I have a local shop building, installing and tunning my 1992 for me. I am going with a forged 383 with afr 210 comp port heads and a lt4 intake with all the supporting goodies. i decided to go with 10:5.1 compression because my blower is only a p600b procharger. I am also going with meth injection. My question is in regards to the cam they chose. Its a comp cam 280xfi hr-13. ...has .anybody on here used this cam in their engine and how did it do?
06-29-2013, 11:25 AM
#2
Team Owner
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St. Jude Donor '05
If it were me Id look into a cam that is designed to work specifically in a forced induction app. not saying you cant use what you got.
Being as the air if being forced, not so much as drawn in you can play with timing events to really take advantage of the boost and not have the cons of a cammed NA engine.
Being as the air if being forced, not so much as drawn in you can play with timing events to really take advantage of the boost and not have the cons of a cammed NA engine.
06-29-2013, 12:37 PM
#4
Team Owner
http://www.hitechmotorsport.com/. I believe they will make recommendations based on what you have and custom grind you a cam. That is what they did for me.
06-29-2013, 12:41 PM
#5
http://www.hitechmotorsport.com/. I believe they will make recommendations based on what you have and custom grind you a cam. That is what they did for me.
Thanks. Ill look into it. The shop already has this comp cam and they said they chose it carefully considering everything done. I guess I will go with what they wanna do. Afterall they are the professionals.
06-29-2013, 10:34 PM
#6
Race Director
I have p600b, afr195 comp eliminator, ARH 1 7/8" stepped headers on my 93 vert 6spd.
Im running a lloyd elliot 224/236 114 LSA, .576ish lift (1.6:1 roller rockers).
You want that LSA (lobe sep angle) to be high compared to what you'd choose on a n/a motor because youl lose boost out the exhaust during the overlap phase of the cam.You want to minimize the overlap phase. Also makes exhaust cleaner too (but negated by the higher overall duration of the cam compared to stock).
THe next big trick is make your exhaust as free-flowing as humanly possible. 3" duals, no cats, headers.
This is because during that overlap phase, the boost fights exhaust backpressure to fill the cylinder. So f you make 10 psi boost, but have 8 psi backpressure then you only get 2 psi boost during the overlap phase
Im running a lloyd elliot 224/236 114 LSA, .576ish lift (1.6:1 roller rockers).
You want that LSA (lobe sep angle) to be high compared to what you'd choose on a n/a motor because youl lose boost out the exhaust during the overlap phase of the cam.You want to minimize the overlap phase. Also makes exhaust cleaner too (but negated by the higher overall duration of the cam compared to stock).
THe next big trick is make your exhaust as free-flowing as humanly possible. 3" duals, no cats, headers.
This is because during that overlap phase, the boost fights exhaust backpressure to fill the cylinder. So f you make 10 psi boost, but have 8 psi backpressure then you only get 2 psi boost during the overlap phase
06-29-2013, 11:02 PM
#7
I have p600b, afr195 comp eliminator, ARH 1 7/8" stepped headers on my 93 vert 6spd.
Im running a lloyd elliot 224/236 114 LSA, .576ish lift (1.6:1 roller rockers).
You want that LSA (lobe sep angle) to be high compared to what you'd choose on a n/a motor because youl lose boost out the exhaust during the overlap phase of the cam.You want to minimize the overlap phase. Also makes exhaust cleaner too (but negated by the higher overall duration of the cam compared to stock).
THe next big trick is make your exhaust as free-flowing as humanly possible. 3" duals, no cats, headers.
This is because during that overlap phase, the boost fights exhaust backpressure to fill the cylinder. So f you make 10 psi boost, but have 8 psi backpressure then you only get 2 psi boost during the overlap phase
Im running a lloyd elliot 224/236 114 LSA, .576ish lift (1.6:1 roller rockers).
You want that LSA (lobe sep angle) to be high compared to what you'd choose on a n/a motor because youl lose boost out the exhaust during the overlap phase of the cam.You want to minimize the overlap phase. Also makes exhaust cleaner too (but negated by the higher overall duration of the cam compared to stock).
THe next big trick is make your exhaust as free-flowing as humanly possible. 3" duals, no cats, headers.
This is because during that overlap phase, the boost fights exhaust backpressure to fill the cylinder. So f you make 10 psi boost, but have 8 psi backpressure then you only get 2 psi boost during the overlap phase
I have pretty good exhaust i believe. I am running the same headers as you have with the x pipe and 3 inch magnaflow. But I am also running electronic dumps.
what kind of power do you make to the ground and are you running a stock lower end?
06-30-2013, 06:04 AM
#9
Lol the car will be used at the autox track, road america, and some strip nights. Im no newby to driving. I am getting out of motorcycle racing and taking up a new hobby.
06-30-2013, 08:00 AM
#10
Race Director
Interesting. Ed, my tuner, mentioned that today and said that is why we were going with the 113 lobe sep.
I have pretty good exhaust i believe. I am running the same headers as you have with the x pipe and 3 inch magnaflow. But I am also running electronic dumps.
what kind of power do you make to the ground and are you running a stock lower end?
I have pretty good exhaust i believe. I am running the same headers as you have with the x pipe and 3 inch magnaflow. But I am also running electronic dumps.
what kind of power do you make to the ground and are you running a stock lower end?
There's 400 + rwtq at 3000 rpm, so its funto drive everyday. I had too much downlow spark advance and found that removing 4 degrees of timing in the 2600 to 3400 range actually increased tq/ power by 15 to 20 rwtq. Note that this what not due to knock sensors either as I was monitoring those.
When I added the heads, I got bigger 61cc chambers to drop cr to 9.7:1
Also meth/ water inj
Stock bottom end. Not worried (maybe a little about the cast crank, but the corvette is a light car so stresses there are reduced).
06-30-2013, 08:17 AM
#11
Last year (before the bigger 1 7/8 stepped headers and 3" duals) I was making 510 rwhp at 5400 rpm/ 11 psi boost. I would have ran it higher, but I was being careful as I dialed in afr
There's 400 + rwtq at 3000 rpm, so its funto drive everyday. I had too much downlow spark advance and found that removing 4 degrees of timing in the 2600 to 3400 range actually increased tq/ power by 15 to 20 rwtq. Note that this what not due to knock sensors either as I was monitoring those.
When I added the heads, I got bigger 61cc chambers to drop cr to 9.7:1
Also meth/ water inj
Stock bottom end. Not worried (maybe a little about the cast crank, but the corvette is a light car so stresses there are reduced).
There's 400 + rwtq at 3000 rpm, so its funto drive everyday. I had too much downlow spark advance and found that removing 4 degrees of timing in the 2600 to 3400 range actually increased tq/ power by 15 to 20 rwtq. Note that this what not due to knock sensors either as I was monitoring those.
When I added the heads, I got bigger 61cc chambers to drop cr to 9.7:1
Also meth/ water inj
Stock bottom end. Not worried (maybe a little about the cast crank, but the corvette is a light car so stresses there are reduced).