Originally Posted by LS1curious

hmm I think you don't understand highoutput 4cylinder ITB stuff. 90 kpa idle on its best day.

No matter what you do to a carburator it'll never be anything beyond a gas can with a straw sticking out of it period.

You can add a ton of air bleeding and emulsifiying orifices and circuts you can redesign the discharge orifices all day but its doesn't change that fact ever. A carberator is a pressure differential device. No pressure difference no function. Sure a carb can tolerate low idle vacum becuase the venturi it self genrates Some of the signal. but as soon as that fuel hits the plenum it falls right out of suspension.

we have a huge difference between a Electronics guy and someone who does what he talks about for a living. Honestly the EFI system is not holding the EFI pro-mod back. Something else in the system is.Could be the ratting for flow on the TB's honestly. You have one TB with a rating at 1.5 inchs of mercury and another at 28inch of water deprssion. You also have a laminar flow elemnt in the carberator which is the venturi itself the helps drive airflow through the plate.

but I am done with this topic. EFI wins if carbs are so great why is proof is in the pudding. F1 runs EFI. if a carb had an advatage I think the companies spending millions daily to find HP would be all over it.

If you want to talk fankly about fuel atomoization differences between carberators and EFI glad to have that discussion.

Originally Posted by WOTFMAN

Carbs make more power then EFI because of fuel atomization properties. The droplets turn into vapor in a well ported intake and cylinder head. So fine a mist/vapor that you can make the power over EFI.

Originally Posted by stevieturbo

That may be true....

But peak power is only a number.

Id rather have a very wide spread of power, than a simple big number over a narrow rpm band.
If high numbers were all that mattered...maybe we would all run big 2 stroke engines, that make no low end power or torque, but very impressive numbers at the top end.

A carb can maintain good AFR's etc over a limited range of operating conditions, whereas EFI can maintain optimium AFR's under ALL conditions. So generally speaking, in most cases, it will offer better performance.

Originally Posted by stevieturbo

That may be true....

But peak power is only a number.

Id rather have a very wide spread of power, than a simple big number over a narrow rpm band.
If high numbers were all that mattered...maybe we would all run big 2 stroke engines, that make no low end power or torque, but very impressive numbers at the top end.

A carb can maintain good AFR's etc over a limited range of operating conditions, whereas EFI can maintain optimium AFR's under ALL conditions. So generally speaking, in most cases, it will offer better performance.

Originally Posted by LIL SS

This has gotten pretty far off track and turned in to a Carb vs EFI post, not the intended Vizad LSA argument.


I have a few questions based more on the original topic.

Say you have 2 cams specs first one being a popular cam:

Cam 1 (108 icl / 110l lsa)

Intake
.006 - .050 - .200
294 -- 243 -- 164

Exhaust
.006 - .050 - .200
300 -- 250 -- 169

IVO .006 - .050 - .200
------ 39* - 13.5* - (-26) --- BTDC

IVC .006 - .050 - .200
------ 75 --- 49.5 ---10 ----- ABDC

EVO .006 - .050 - .200
------ 82 ----57 ----- 12 ----- BBDC

EVC .006 - .050 - .200
------ 38 ----13 -- (-32) ----- ATDC

26.5* overlap
11.03 SCR - 8.02 DCR





Cam 2 (106icl 108lsa)

Intake
.006 - .050 - .200
286 -- 236 -- 159

Exhaust
.006 - .050 - .200
286 -- 236 -- 159

IVO .006 - .050 - .200
------ 37 -- 12* - (-26.5) --- BTDC

IVC .006 - .050 - .200
------ 69 --- 44 ---5.5 ----- ABDC

EVO .006 - .050 - .200
------ 73 ----48 ----- 9.5 -- BBDC

EVC .006 - .050 - .200
----- 33 ----- 8 --- (-30.5) - ATDC

20* overlap
11.03 SCR - 8.47 DCR




Wouldn't cam #2

Have less chance of reversion?
Make more bottom end TQ?
Carry TQ/RPM just about as far as cam 1?
Be "easier" to tune?

Originally Posted by edcmat-l1

Well, duh. Never said it was. Overlap is nothing more than how long both valves are off their repective seats.

Yeah. And the ability to breathe can be influenced, both positively, and negatively by valve events/overlap.


Not really sure what you mean there. Overlap is ONLY defined as degrees of rotation over which both valves are open. So, thats another DUH statement.
Virtually all of the components and specs you've regarded as meaningless, all have an effect on what cam specs will work best.

Originally Posted by WOTFMAN

Cam # 1 will make the better low end grunt. Cam 2 would have more chance of reversion if the intake and cylinder head ports werent tuned for what that cam will want as far as runner length goes.

Originally Posted by LIL SS

This has gotten pretty far off track and turned in to a Carb vs EFI post, not the intended Vizad LSA argument.

Originally Posted by WOTFMAN

Cam # 1 will make the better low end grunt. Cam 2 would have more chance of reversion if the intake and cylinder head ports werent tuned for what that cam will want as far as runner length goes.