Tommy Tucker

Let me know what you have and include the lift and any PtoV clearance issues. Also what you do/don't like about it.
I'm looking to find out how far you can go in this direction without fly cutting.
I have the 5.3 heads.
Tom.

GrannySShifting

iTrader: (10)

Are they milled? What valve size?

Tommy Tucker

Hi GS,
5.3 heads In:2.02 and Ex:1.57 unmilled.

How much extra compression does milling produce? Say 20/30thou.

Ragtop 99

iTrader: (7)

You might define your definition of long duration tight LSA. Some might say a 230/230 112 meets that criteria while you may be thinking 236/242 108.

GrannySShifting

iTrader: (10)

For example a Trex specs to around 243/249 110 LSA. Intake centerline is 108, so that menas full lift of the intake occurs at 108 degrees.

The actual total valve lift, realy has nothing to do at all with piston to valve clearences. The intake valve generaly will hit on th eopening side of the ramp, and the exhaust on the closing side, if Im thinking correctly

CHRISPY

I use 236/242 on 110LSA without problems. I have a 385 though.

Ragtop 99

iTrader: (7)

valve reliefs in your pistons?

Tommy Tucker

Point taken!
For the purposes of this thread I would consider 230+ on a 110 or less.
I know not many guys run tighter LSA than 110/112 but I'm really interested in those that do. I can't find much off the shelf, so I'm wanting to know a bit about their behaviour as well as some spec recommendations. Don't know too many experts on these type of cams in an LS1.

The ramp rate of the lobes will make a significant difference with longer duration, so that's why I was asking about PtoV (i'm sure lift must be important here also) and specific examples.

Grant B

I've been reading this forum a lot, and have noted that people think LSA has a huge effect on drivabliity and idle. Isn't that just because of the overlap? Why would a 224/224 110 be THAT much worse than a 230/230 112? The overlap would be the same, but the valves would stay open longer.

GrannySShifting

iTrader: (10)

From my experience with it, it seems like the idle quality isnt traded off as much as the driveability is. Not that they are not driveable but it takes more work getting them to like being at 1200 rpm pulling away from a light.

Ive done a 239/248 110 LSA on a automatic car, idled at 950 solid, drove very well, got 20+ mpg on the highway. Not much compression in that car though, compresion would have made it even better. Had a little bit of time tuning that car though

DAPSUPRSLO

iTrader: (14)

I run a 230/236 107lsa cam. What do I like about the cam, pretty much everything. What do I not like about the cam, it is deffinately not a sleeper even idleing at 1000 rpm. I used to run this cam with 4.11 gears but have sinced switched to 4.56s with full time bogarts. I am having some transmission issues and loading up at wot issues which I will be addressing this weekend so look for new times with this setup. I'll tell you this. When I put in the 4.56s I ran my friends nitrous 355 lt4 vette. He goes 98mph in the 8th and 123 through the quarter and 11.14-11.4 e.t.s. Up to 100 mph I had a car on him and we were both on sticky tires (him M/T e.t. streets, me hoosier qtp's).

With the 4.11s on nittos and a 3590 raceweight in a m6 I went 11.98 at 119.08 mph on a 1.97 60'. On 16" e.t. streets I went 11.62 at 117.98 mph with a 1.69 60' (raceweight was 3545 for that run).

Tommy Tucker

Thanks Dap.
I'm interested in why you chose that spec? 346ci? Lift? What revs does it pick-up at?

GrannySShifting

iTrader: (10)

I cna actually show you a graph of the cam I was talkign about, vs the cam daily is talking about on the same dyno, 6 speed cars, stock 02 heads on both. If I can dig it up!

DAPSUPRSLO

iTrader: (14)

I wanted to try something on a very tight lsa with more duration but not tight enough to cause p/v issues. At the time I did not have some of the bigger cams available for comparison but you have these cams available now for comparison (TRex). The cam is an animal above 4000 rpm. At 2000 rpm and up it is fairly smooth with just a little break up. I have a true dual exhaust with an x-pipe though. I am also an ls1 edit tuner so this helps me to make this cam run very well on the street. If you are interested in a cam like this let me know. We could come up with something bigger then mine that would deffinately make good power.

When you retard the exhaust lobe by decreasing the lobe separation angle you increase peak torque but hurt rpm potential. I don't know about you but I do not care about spinning my stock 01 shortblock to 7200 rpm. Everyone is different however. So I say make more peak power around the 5500-6500 range, where I race.

RoyO

The cam Im about to take out is a 230/230 on a 110+4. It could use some more tuning but with 4.10s its not bad. It probably gets around 20mpg on the highway. Its only a .573/.573 lift on stock heads so clearance wasnt a problem.

DAPSUPRSLO

iTrader: (14)

Jeff (Granny) if you have my cam dyno I want it badly. My car is an 01 with stock o1 heads. These numbers were through a 12 bolt with 4.11 gears and a posi too pushing 17x11 zr1 replicas (spools will free up some power).

Best rwhp was 392 rwhp and best rwtq was 375-377ish. I dynoed the same day that a cam only car was there with a 226/226 110lsa cam. Through an unlocked auto and a stock 10 bolt he dynoed 362ish.

Ragtop 99

iTrader: (7)

antta:

Based upon the cam threads, I would suggest that straight up would work well. if you really want advance, consider only 1 or 2 degrees of advance.

Tommy Tucker

Yep, the two things I am not interested in are revving past 6500 and crazy lift numbers. I don't plan more than about 0.58 lift in order that I can maintain a relatively stress free valve train even when driving 4K-6K for extended periods. As long as I have the power in that area I don't much need to rev out (not going to need 200mph).
You don't mention lift? Have you got valve-slapping ramps on the lobes?
I'm needing to guage how far you can go on a e.g. 106 before fly cutting is required. Thanks.

DAPSUPRSLO

iTrader: (14)

My lift numbers are 576 on the intake and 573 on the exhaust. I do have the thunder intake 230 lobe so it is pretty agressive. I have been sipping a couple of drinks as of now as it has been a long day at work. I'll get back to tomorow you on the 106 lsa deal based on the TRex dimensions.

GrannySShifting

iTrader: (10)

I was talking about TimGs cam vs yours. His made about 10-15 ft lbs more throughout the whole curve, and 25-30 hp more at peak rpm of 6250. I think some overlap from the exhaust lobe ate into power some though might be why it peaked so early, I think that cam had more then enough exhaust duration

The car your thinking about was crystal, minus a LS6 intake and ASP pulley a 226/226 111 with XE intake lobe and a weird small block chevy lobe on the exhaust (Comp actually sent a lobe other then what I ordered a little too lazy) That setup made 382 locked, and picked up 16 hp next dyno unlocked but it never got dynoed locked again, and crystal being a sissy never raced it. It put a hurtin on burbanmans car with 2.73 gears still in it

If you had ramps exactly what is in the intake lobe of the Trex, a 106 LSA, youd hit the limit at roughly 4 degress smaller then Trex, (its actually a 243.5 intake lobe or something), installed at a 106 intake centerline.

I dont think that given your p/v clearence requirement that the medium duration cam youll be running will be well suited to a pretty tight lobe, unless your running some MILD ramps like the Aussie guys are doing. And then individual TBs, speed density becomes something to look at.