KonnietheGoat

Dan, your results do not surprise me. With out a cam timing adjustment, even with tuning, you wont see much change. The specifics of the cam will determine if you can adjust it, or if you just need a new cam.

DanZ28

iTrader: (5)

230/234 580/590 114 ICL/LSA, straight up. Pretty sure a cam swap was in order. Ive seen cams all over the place on the LS1 engine, just when you think you know what works best, you try something a little or a lot different and it still seems to work. I think in my particular situation a new cam and porting on the Vic Jr were in order just to get me even with the FAST 90 setup. I think my TRex would have worked better with the 110 LSA on a 108 ICL in that comparison. None the less, live and learn .

Dan

Qwiknotch

Yeah, cams are always the mystery power maker. The key is to get the right cam for the combo and even then you could be off. The guys with the engine dynos are the lucky ones that can try several different cams to get the right cam.

KonnietheGoat

Cam design is a black art, one step below necromancy.

1bad lad

i did a test using a head that flowed 360 then puttin on the ls7 intake it only flowed 310cfm soo......on a sf-600 bench then tried the single plane style intake on same head and it flowed 350cfm so with the correct camshaft design theoretically the single plane should make more power...now i understand there is a few more variables so........just a little info

lilmachine

Thats it......kickass heads are useless without an intake that can feed them. LS7 heads are great, but every single person out there running them has heads that are a waste. Until an intake can flow 400+, LS7 heads are useless to buy and expect anywhere near their potential in performance. Just get L92's for close to half price.

Whats the rule-of-thumb??? ~1 hp increase per cfm increase in flow, right? So an LS7 head flowing 400 cfm with an intake flowing 350cfm makes the LS7 heads waste about 50 hp. 365 cfm L92 heads are the better buy and the better head with that 350cfm intake.

njc.corp

nice thread fella's-

STROKER R/T

this is good info !!! now throw out your advertised cfm ...take your heads to get flowed.... match it up to your intake ..then shake the dice on your cam choice...unless you have a killer tuner [ i have ] .... or your tuner has an engine dyno..$$$$$ ...wouldn't it be nice if it was included in the purchase of your build ..reality and the cost will prevent this from coming to life..

lilmachine

Prevent what from coming to life? The LS7 heads with a carb style intake and elbow.......WHY? Is this an over-the-edge combo to try?

Hearing alot of that around this forum...."can't be done", "won't work", "wasting your time". Whats the deal with that?

STROKER R/T

to quote my post i was referring to engine builders testing cam selection on engine dyno before selling NOT HAPPENING !!!

WizeAss

iTrader: (5)

what he is saying is that no one who knows cam specs is speaking and anyone who has tested a single plane intake with the L92/LS7 heads and various cams has not posted results of their efforts. Everything is under wraps because most that go with a carb style intake are looking for serious RPM and peak numbers (that are normally not optimal for everyday street use) and these folks have competitive cars and dont willingly share results.

So all you can do is combine the theories and share with a cam expert to derive at a "assumed" effective solution.

For instance. Considering the I/E Ratio of the heads.... it makes since to go with a wider split. Since short runner Single Plane Carb intakes like really low LSA's it makes since to go with something closer to a 109-111 vs a 112-115 that the composite long runner intakes see.

In my opinion.... all these Vette guys with thier baby cammed L92 projects looking for 500rwhp are ruining any opportunity to really achieve some R&D for those that dont have a chassis or engine dyno or money to install/grind 5 different cams. Most folks that have done this head are the Vette guys.

I am looking for the day when someone else does a stroker, LS3/L92 Head, GMPP Single Plane built for a nice shot of nitrous on a hydrolic roller and has some numbers. If you ask the same for Fast90/90's, ET, TFS or AFR headed strokers you will hear tons of numbers and cam results.

lilmachine

Oh.

KonnietheGoat

Yup, there is no R&D, and most people/shops are being very tight lipped. and it is sad in a way. But, I bet if you call one of the few places that can do a custom cam, and know their stuff, you will get the right cam. There's no dice rolling about it. Cam design is a black art, but the basics are simple, and theres software available that can help narrow down the choices.

The only reason Im being as open on my build as I am is that its a school project, and im also using it to showcase my skills as i begin my job search. I doubt that I ever disclose the full cam specs. But, it is a 110 LSA, dual pattern, asymetric lobe design.

And the reason for everything is to maximize the flow/pulse of the induction system. Aside from the basic general attributes, anything with a number attached to it is going to vary by your head choice, displacement, manifold, power goal, car usage and other factors.

So its really not worth giving out the specs and have them become one of the daily 'which cam' pissing matches that occur on every automotive forum. 95% of cams are picked based on cost or sound anyway. The power they make is ancillary to the average buyer.

For those of us who chase after power like fat kid after cake, I'm certain that some one will eventually market and sell a topend/valve train package for LS motors using a carb manifold. It's a very recent devlopment taht anyone has realized how crippled we are by the plastic intake. Thats why it took almost 10 years for carb inatkes to be marketed for the engines. Everyone thought the plastic **** would be fine/better. Plus it takes alot to retro fit the EFI stuff to carb manifold. You have to figure out connections and locations for MAP, Evap, Vacuum for the brakes/HVAC, PCV, fuel rail mounts, and Injectors (anthough several new models have these as an option). Then you have to find gaskets, which fel-pro has stepped up to make, and you need to have better bolts than what GMPP sends you, IMO. In other words, carb manifold builds are best left to great shops, and the maybe 1% of people who really, really know their **** at this time.

Qwiknotch

Mine will be a carb intake with an HP 750 carb. I am a fan of fuel injection, but for ease of installation and my desire to not have to wire my car, I am going to run the carb with MSD coil packs. I thought about buying the conversion kit to use a ford ditributor, but to hell with that, the coil pack will deliver a far superior spark..

As far as cam specs, I will be completely open with the results, once I start messing with cams. I was going to use a solid roller setup, but for the rpm's I will be spinning (less than 7500) this engine, I have no need for it.

toneloc60

iTrader: (7)

I hate to tell you this and have to follow it up with you'll have to wait to see; but my build should help a lot of people here with questions about the abilities of an LS7 head stroker. I'm still a couple parts short of having my engine together, but I'll post the engine dyno graph when it's done.

The engine:
441 ci LSX block
4.125" Callies Compstar crank
4.125" custom Wiseco pistons for large nitrous shots (300+)
6.125" Lunati Pro Billet Rods
Ported and polished LS7 heads with Ti intake and sodium filled exhaust valves with 65cc chambers
Meziere electric street water pump
LS7 carb intake
double roller timing chain
Melling high volume/high pressure oil pump
1 3/4 QTP long tube headers
MSD coils and wires

will be running a carb tuned for E85
won't have N2O until I come home from Iraq, so all #'s will be NA
will be having a custom grind cam made after the builder ports the intake for the heads and re-flow tests
last flow test on the heads said 370 intake and 256 exhaust CFM @ .700 lift on a 4.000" test bore. Would like to have had a 4.125" test bore.

lilmachine

You need bigger headers. 1 7/8" stepped to 2".

Which LS7 carb style intake are you using? GM?

Big Bird WS6

iTrader: (9)

ok so we all basicaly agree that the carb plate is better then an ls style. well what about with FI. does that change anything?
and second lets say money doesn't matter.
what about a sheet metal intake. like wilson or beck?

WizeAss

iTrader: (5)

yes.... carb is better for FI..... but intakes are not all too important when you are forcing air down a head. Most that go with it are looking for large amounts of boost and they fear the composite/plastic stock style not handling 20psi plus worth of boost.

A sheetmetal owns all. Either wilson or beck... doesnt matter. Those intakes flow as much as the head will allow it to and as much as the engine will injest.

toneloc60

iTrader: (7)

I'm going to test with the 1 3/4 headers and the 1 7/8. I want to see which will have a broader torque band.

The only one I can find right now is the GM LS7 intake. If you have a link to another I'd be happy to check it out.

Qwiknotch

If money is no object and you are not running a class that does not allow sheetmetal intakes, then a sheetmetal would be the best, for carbs or fuel injection.
CFE, Wilson, Hogan's.... any of those also would be a good bet