I'm having a 383 lt1 built for use with a t-trim. I'm considering going with a solid roller cam. Emissions is not an issue. Do you all think it would be wise to go with a solid roller and if so, what specs would you suggest?

BTW, i'll be bolting on fully ported LT4 heads/intake. My goals are around 650rwhp.


[Modified by spraydformula, 7:20 PM 1/31/2002]

 

I posted a reply in the other thread also, but additionally, what kind of RPM are you looking at turning?

 

with a blower, i'll turn 6500 max. but I wanna produce power all the way to redline

 

Solid with a blower - even a small solid - will probably be happier with closer to 7k shift points - is that out of the question?

Chris

 

Thats not out of the question at all. I was questioning the ability off the engine to rev that high with a blower seeing has how thats what I really had in mind anyway. If a solid roller (with a blower) likes to see 7k shift points, then 7k it gets! How crazy do you think i'd be able to get with lift specs before I start getting into overlap? Remember that emmisions is not an issue in my application.

BTW, I was planning on going with a cogged setup on the t-trim. What do you suggest?


[Modified by spraydformula, 1:31 PM 2/1/2002]

 

http://www.cranecams.com/master/apps/chevy35.htm

This is Crane cams line of S.R. Supercharger cams. To get your power level you need to figure out a custom cam on some program like desktop dyno. I would exceed .600 lift and 112 LSA

 

Isn't a 112 LSA to narrow for a blower application? I was thinking of staying around the 114-115 area. That way I wont just blow a bunch of boost right through the exhaust valves. I figured i'd have to either go to or exceed .600 lift which I don't have a problem doing. What springs would you suggest I get?


[Modified by spraydformula, 6:58 PM 2/1/2002]

 

The key word is exceed. That means more than 112. Crane uses 112 on the low end S/C cam. If you look at the valve event numbers for that cam the I'd bet that the overlap is less than 20 degrees. But that cam will never get you 600+ RWHP.

Crane cam cards always have their recomended spring and they give a valve float rpm. IMO always go with more spring pressure and the biggest diameter you can get away with. Presently I have 1.56's with a closed pressure of 195#'s good for up to .700 lift. So I'm not stressing at .635/.644

Give me your valve size and CFM, C/R, c.i, header size, boost psi I could tell you aprox. what cam size DD2000 will say you need. I will tell you right now your heads and intake and probably your exhaust are limiting factors.

 

2.02/1.6 valves, 302 cfm (Fully ported AFR LT4 heads), 9.0:1 C/R, 383 ci, 1 3/4 inch AS&M shorty headers, 15-17 psi of boost through a Vortech t-trim

 

Are you going with an aftermarket computer (SpeedPro/FAST, etc?) If so I would set up everything for shift points around 7200-7300. Cam spec wise I would preferr to see the flow sheet for the heads (and if you have intake/exhaust CC's, discharge coeffecients, etc. that would be great), but initially would look at something in the 242/250 around a 115+3.

You might also consider ditching the shorty headers and going to a good set of longtubes.

 

ChrisB,
Comp told me that my combo would like higher RPM as well. I just have dreaded the thought of pushing that much mass to 7K+. I have the lightweight crank, Oliver billets, and J&E customs, but on the dyno still stopped at 6300. The HP was still climbing, but I was not comfortable to continue. The motor has like 2200 miles, and I am not ready to replace any time soon.

The cam I use is the CC solid roller with 114°, 238/244 @ 0.050, with nearly 0.650" lift. The engine makes in excess of 680RWHP at 11# of boost at 6300. I will say this, when you are rotating the engine over for valve adjustment, those valves sure open a good distance. Heads are AFR215CPs, and I run the MRII with 9.5 scr. The car is very streetable and makes good power at the lower RPMs as well.

Maybe one day I'll try the higher RPMs, but for now I'm satisfied. Besides I need to get it to HRP before I do any additional work.

Aaron

 

Like the other said you really need and honest CFM flow sheet for the heads. I don't see how they can get 302 cfm around 2.02 valves. I couldn't figure out how to change DD2000 to JPEG to post. I ran this with my heads.

I ran the supercharger that gave the most cfm. I'll correct it with your model when you get good CFM numbers. If i change the exhaust the numbers will go up

Chevy 383

1 4.030000
1 3.750000
8
Wedge/Fully Ported, Large Valves

1 2.080000 intake
1 1.600000 exhaust
1 9.000000 C/R

Forced Induction

Gasoline

Centrifugal- Vortech V3-R

1 900 max cfm

1 14.000000 psi


Dual Purpose Street

Roller

Dart215.flw

Wedge/Fully Ported, Large Valves

1 2.080000 intake valve size

1 0.200000
1 0.300000
1 0.400000
1 0.500000 lifts
1 0.550000
1 0.600000
1 0.650000
1 0.700000
1 144.000000
1 193.000000
1 238.000000
1 278.000000 CFM at the above lifts
1 288.000000
1 294.000000
1 302.000000
1 306.000000

1 1.650000 ex valve size

1 0.200000
1 0.300000
1 0.400000
1 0.500000 lifts
1 0.550000
1 0.600000
1 0.650000

1 116.000000
1 155.000000
1 198.000000
1 222.000000 CFM at the above lifts
1 226.000000
1 232.000000
1 232.000000


2000 173.378784 455.119324
2500 236.304565 496.239594
3000 296.432648 518.757141
3500 360.638489 540.957703
4000 425.935272 559.040039
4500 492.829987 574.968323 hp & tq
5000 551.789001 579.378479
5500 602.969543 575.561829
6000 639.817017 559.839844
6500 668.846619 540.222290
7000 682.494873 511.871185
7500 691.706482 484.194519
8000 673.543518 442.012939


Cam @.050 242/254 .600/.650 113.5 lsa intake timing 11/51 ex time 64/10





[Modified by gkull, 8:55 PM 2/1/2002]