guys, the car is up and running now w. a comp camps solid roller cam that is 248/254 @ .050, .577/.583 lift on 114. the car lacks low end torque and idles fairly rough, the cam ended up being for a supercharged application. the car is a '69 camaro convertible, weighs 3900 lbs. the engine has brodix track 1 heads, 225 int ports, victor jr intake, qft 750 blow thru carb, 9:1 compression, twin t3/t4 turbos. car currently has a tremec 5 spd and 4.10's(which will be changed to 3.55). comp is trying to make this rite and initially recommended a 214 at .050 duration/.540 lift/112 center, which i felt was too small, now they are recommending 224 at .050/.550 lift/112 center. i also contacted bullet, they recomend a 244 duration, .560 lift, 114 center. the car is mostly street driven and goes to the track 3x/ year. i'm more confused now then ever!!!! i run 10 psi boost, happy w/ wot performance but not the rest!!!! thanks!!!!

 

5spd, big heads, VicJr, only 9:1, heavy car... Go with the smaller cam, it'll make a world of difference in the low end and probably won't hurt the top end enough to notice.

 

:agree:

 

thanks guys, i was getting a headache from all of this!! even crane and crower sugested cams in the 238-244 range as well ground on a 114 center

 

Its all about the combo . You cant go wrong with Mark at Bullet . Sit down and give him a call . I say sit down because he will talk your ear off about this stuff . Great guy to deal with , and this guy knows turbo cams !



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If comp is trying to make it right and seeing you have a solid roller here's what I had them grind for my 383 on E85. I installed it straight up @ 114icl and on the engine dyno it made over 700 ft. lbs from 4000 and up and 810 hp @ 6000 with only 10psi. Also at 19psi it made 1058hp@6000 still climbing but the fuel pump wasn't up to the task on the dyno so thats where we had to quit. I don't think you need anything bigger than this. Idle is barely noticable and drives great too.

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what is the rest of the combos on the 383 and lt1? thanks!!!

 

My 383 is as follows

Dart little m block, eagle crank and rods, custom CP pistons 9:1 compression
AFR 210 comp ported heads, Cam as above, vic jr intake
CSU 850 blowthrough, twin Mp t70's .96 a/r turbines, no intercooler
In my 4200lb GMC truck it ran 10.80s with 10 psi on a slippery track on gas.

 

The LT1 on the cam spec is because I'm using a Dart SHP block and it has provisions for a cam retainer plate .


383ci sbc
9:1 Diamond pistons
Eagle 4340 crank and H beam rods
Vc Jr intake
AFR195 street heads 75cc chambers , AFR-8019 springs 155lb / 412lb
Comp Pro Mag steel rockers , Comp Pro Mag Hyd roller lifters
750cfm blow-thru carb
S480 turbo 22psi
Hyd Roller cam , specs above

4450lbs
TH400
3.73 gear
31" slick

 

Keep in mind the OP's got two little .63 T3/stage3 turbines...

You know, I'm a little surprised that setup doesn't start making boost at 1/4 throttle and around 15-1800rpm. :hmm:

 

missed that .

 

I think the point to be made was made by what Blown385 and I posted on our combos. If we only need 236@ .050 to make over 1k the op's combo wouldn't need that much let alone a solid roller cam. Those turbines are a gross mismatch to everything listed no matter how you look at it and will be the limiting factor in any decision made.

Actmobar, if there is any way possible to put something with t4 turbines in there you would be much happier. The rest of you're engine dictates this and would prbably be much better all around.

Just my opinion however.

 

is there anything i can use in a t3 flange style or do i need to cut the flanges off?

 

I'm still curious why it's not making boost at more or less just above idle. Like, say you're in 4th gear, 30mph, very light throttle. Roll into it somewhere between 1/4-1/2 throttle and hold it there... how long does it take to spool up? What RPM?

 

in 5th it'll go into boost around 23oo rpm, what about a gt35? my taget hp is 750-800 hp. this cam that is in the car has 10 deg more exhaust duration then the intake duration, was wondering if that was why it is slow to go into boost and the motor is lazy

 

the reason i mentioned the gt35 is that it appears they make it w/ a t3 exh flange, so it wouldn't take alot of modification to fit everything

 

I ran a hydraulic flat cam that was 234º/244º in a 9.5:1 377 SBC and it worked well. The split duration should not be hurting you IMO. The cam I am running now is in the 25Xº @ 0.050 and it is strong AFTER 20 psi. It seems sluggish and lazy anywhere before that.

 

The engine fails to make boost instantly because of the engine's lack of airflow at lower rpms due to the camshaft being way too big in duration. This is shown by the lack of low end torque. With an automatic and a loose converter it would hide a lot more of the problem. Just because the turbines are small doesn't mean fast spool if there is a big mismatch of parts.

Put that 224@ .050 cam in your first post in there and it should make some torque and spool should be instant. It should be night and day from what you have now. Should be able to make power to 5500 with that cam however the turbines may hold it back up top.

 

Have you ever had a motor with that size cam or duration figures in the past? Honestly that cam isn't way over large but given your tiny turbo's it is. If it were an NA motor with 10.8:1 comp it would be fine, but you do weigh over 4000 pounds with you in it right? I have a cam like that in a solid type same duration and very slightly less lift and I love it. I'll take a rough idle any day over one that lopes or plain ole smooth, its a hotrod and its supposed to be a bada**ed ride.

 

w/ me in it it weighs 4k lbs, maybe w/ the vette clip and aluminum heads on the new engine(and no blower) it weighs 3800, i'm thinking i need to do the cam first and then deal w/ the turbos, i figured i'd reach my target 750-800 hp w/ the turbos that are on it