Schantin

iTrader: (6)

After a week of reading threads and sticky's, using the Ve calculator, etc, etc. Here's what I've got:

1. Have stock LS1 heads being poted/milled a bit/flow tested at Va Speed. Guessing I'll end out w/ a 65cc chamber volume. Had dual springs installed w/ it.

2. Started looking for a cam to match these heads. To get a DCR of around 8.5 it seems that the duration needs to be very short. Seems contrary to all the big monster cams running about (MS3, Vindicator, TRex, etc). Put the specs for a Vindicator into the Ve calculator and got a DCR in the low 7's. Shouldn't that make the car run like a dog till 5K RPM or so? Even a "small" TR224 cam only gives a DCR of 8.21 w/ the heads listed above, which I thought was not optimal.

3. Looked into smaller cc heads. AFR's at 62.5cc's mathmatically will be monstor w/ the TR224 112LSA cam I have sitting in the garage right now.

Decided to see what I could run w/ 59cc Patriot heads.....came out w/ a 228/230 112LSA combo as an ideal 8.5ish DCR.

So.......based on the "math" I've done, how the hell are the big cams making such big power? How important is DCR then vs other factors (overlap, lift)?

My goal is for 420ish RWHP (through a Moser 9" and 4.10's) w/ very good torque in the 2200-5000RPM band. Also have LT's, GMMG, K&N FIPK2, 60lb injectors, aftermarket rails, etc. BTW (as this is important), I'm not looking to spool the car past 6400 on a daily basis.

So....the more reading I do the more Q's I get. Any $0.02 would be greatly appreciated, as I'd like to do this right the first time.

brad8266

iTrader: (23)

Building a motor around DCR is stupid IMO.

I do like your final combo though except for the 60Lb injectors, that too biug for a 420HP car.

ZL1Killa

iTrader: (17)

60lb injectors.. you won't need those unless you are going to be making WAY OVER 550HP Naturally aspirated.

this isn't the boosted world anymore if you are going N/A, a LOT of things change. why you get rid of boost?

Schantin

iTrader: (6)

Well, that's a start So, aside from the 59cc heads and 228/230 combo, what would you recommend? Again, the more research I do.....the more Q's I'm having.

BTW, I've had the MotoTron 60's in the car for over a year now. They run fine even w/ the current H/C "no-turbo" setup. No sense getting rid of them since they're doing their job...........besides, the ARP studs and adjustable return-style fuel system are overkill for N/A too

Redlinez

iTrader: (5)

Their 228 cam should do you just fine. What I've been seeing work well is a 224-228 ish cam 600 or less lift 111-114 plus a few ground in on XER lobes. That cam just seems to do it all quite well, especially for a street car. Now a car that sees a lot of track time and one you don't care so much about bottom end and driveability, that opens a whole nother can of worms.

35th SS

iTrader: (2)

what casting# are those stock ls1 heads your having ported and milled if I may ask.

Schantin

iTrader: (6)

Whatever came w/ my 02 Z28 from the factory Rex. I replaced them w/ the Patriot Stage 2.5 LQ9 heads when I had the STS turbo. Was getting the stock ones ported for a friends car. He doesn't want them now....but am still getting them redone to possibly use on mine. Whether or not I use them will depend on the final flow #'s and compression ratio.........

35th SS

iTrader: (2)

that would be 241s I believe same that came off my 35th.if you could get a hold of a pair of 243s it would be a step up with a vlv. job also.

WeathermanShawn

iTrader: (1)

Schantin:

I'll be a little easier on you here.

Determining various cam and head options can be quite confusing, complex, and like you have had more questions than answers at times.

The first approach to any problem-solving challenge, is to respectfully sort and separate all the various opinions from sound facts.

It is true that building a sound engine capable of producing the HP/TQ you want, involves more than just DCR computations alone.

However, after spending nearly a year reading, studying, and listening I became a true believer in the DCR principle.

Hitting that 8.4-8.7 DCR range, almost always produces great throttle response, power under the curve, and that great feeling of explosive low to upper middle range TQ that most people want.

I agree that a cam in 224-228 range with a 62cc head, is a sound decision.

My combination (DCR ~8.54) has been a blast on the street, and even at Denver's high altitude/DA has netted some very respectable trap speeds.

One note; when I calculated the DCR of your proposed 228/230 cam with the 59cc head, I came up with ~8.74 DCR. That's calculating with a +2 advance. Might want to check that out. I use the Pat Kelley calculator.

Being out west there are not that many LS1 speed shops in the area. But, I have been impressed by many of VA Speed's results and their general approach in engine building. I would think they would be of great help to you.

Apologize for the long response, but many of us have been exactly at the same point you are at.

Good luck.

..WeathermanShawn..

00pooterSS

iTrader: (40)

I would think that cam and small chambered head would work better without the advance in the cam, should bring the DCR down a bit without the advance.

Schantin

iTrader: (6)

Thanks for the great info. BTW, I didn't calculate an advance when I did the 228/230 computation

00pooterSS

iTrader: (40)

That advance will be important because it will change the valve open/closing timing.

Patrick G

iTrader: (14)

Don't choose a cam based on DCR. Choose a cam based on achieving your performance goals based around your mods. Overlap is the most important factor. Have to use enough, but not too much. Drivability and rpm range is second most important. Match all this to your total mods will determine the proper valve events. LSA and DCR are just by-products of those valve events. The proper valve events are what you shoot for. Not LSA or DCR.

Schantin

iTrader: (6)

Appreciate the honest and helpful responses I've received. Finally made a decision/purchase today. Here's what the new combo will be:

243 Casting heads ported by Va Speed w/ Patriot Dual Gold Springs.
228/232 .600/.600 111LSA cam
Hardened pushrods to fit the heads/cam (7.450 I think..........)

Already have LS6 intake, DynaTech 1 3/4" headers, GMMG exhaust, K&N FIPK2, MotoTron 60's, Racetronix pump, ARP studs, Textalia clutch, Moser 9" w/ 4.11's, SD tune, and a bunch o' other crap.

Should be fun once done The price was pretty good too

Hoping to have some track times on it w/in a month.

WeathermanShawn

iTrader: (1)

Yes, Patrick G put it best. Great description of cam theory and application.

Very informative post.

Schantin, looks like a good cam choice. Lets us know how it goes.

Good luck.

..WeathermanShawn..

Patrick G

iTrader: (14)

Very good heads and cam choice. Va. Speed has their act together.

JPH

iTrader: (2)

Good answer Pat.