10k in pocket. New block or EFI ?

[RodKnock]

For better Webers versus Dynatek numbers, as they relate to Dean Lampe's RCR40, I started this thread some time ago.

Dynatek & Dean Lampe's RCR 40 in Kit Car Mag...again

I'm willing to bet that Dean had both his Weber and Dynatek setup operating at or near peak efficiency. The winner was Dynatek. The only negative is cost from what I can see.

[cobrarkc]

I no expert but the Dynatek system will flow 3000cfm and with EFI and a wideband O2 sensor you can infinately adjust the A/F for optimum efficiency the whole rpm range. How could you possible do that with a carb?

[FUNFER2]

I agree. With EFI supporting the cfm and other parameters, with the computer adjusting on the fly, how can a carb. do the same ?

[Cobrabill]

[quote=cobrarkc;. How could you possible do that with a carb?[/QUOTE]

Easy-get a big enough carb.For example:Two Dominators would fill that bill.And what good does a 3K flow capacity do for you if you don't have the intake,cam,heads or exhaust system to utilize it?

Rich-please read what i typed.I said there ARE other benifits to FI.Such as more precise A/F metering.That does not increase peak numbers.

[Cobrabill]

[quote=Great Asp1) Do you know what a T-bone looks like?

2)When someone says that let me know.

3)Gee thanks. I guess a Volkswagon would have been more practical. I'll have to re-think this whole Cobra thing E[/QUOTE]

1)Sure.Another non-sequitur would be nice
2)You did.But not in so many words.
3)Don't get all worked up fer christ sakes.If WE were the pratical type,this board would be a ghost town.And the last time i looked,the FI/carb debate wasn't Cobra specific.


My whole point is that for people chasing the almighty HP,FI isn't the answer.

[Cobrabill]

Originally Posted by FUNFER2

I agree. With EFI supporting the cfm and other parameters, with the computer adjusting on the fly, how can a carb. do the same ?

Keven,does that computer change how much air will fit thru the throttle blades,intake runner or past the valve?

[olddog]

Originally Posted by Cobrabill

Injection is injection.I don't care who's it is.Peak HP is determined by how efficient a air pump the engine is.Fuel delivery system is ALMOST irrelevant.

You can flow a bunch more air down a pipe, at a given delta pressure, than you can air with 8% gasoline mixed with it. Fuel laden air does not flow well in a manifold. So at least in theory, an engine can pump much more air if you don't mix the fuel into the air right at the begining, like a carb or throttle body injection does. Ideally the fuel would go in via direct injection into the cylinder after the intake valve was closed.

By its very nature a carb has to create a low pressure zone to suck the fuel through the jets, creating a flow restriction. EFI does not have this problem.

Now the factory EFI stuff was designed for good emissions and low end torque. On Hp it does not compete with a carb. Most of the aftermarket stuff is patterned off the factory systems and still trying to meet emissions. It would not surprise me at all if an aftermarket EFI system, that was design from the ground up to make power and not care about emissions, made more power than a carb.

[stuartb]

For me it was an easy choice, EFI was the way to go with a change in altitude of about 5000 ft. on my normal drives.

[Fordzilla]

A Hampton Blower was the choice for me. Plenty of flow!!

[Cobrabill]

Originally Posted by olddog

1)You can flow a bunch more air down a pipe, at a given delta pressure, than you can air with 8% gasoline mixed with it. Fuel laden air does not flow well in a manifold. So at least in theory, an engine can pump much more air if you don't mix the fuel into the air right at the begining, like a carb or throttle body injection does. Ideally the fuel would go in via direct injection into the cylinder after the intake valve was closed.

2)By its very nature a carb has to create a low pressure zone to suck the fuel through the jets, creating a flow restriction. EFI does not have this problem.

3)Now the factory EFI stuff was designed for good emissions and low end torque. 4)On Hp it does not compete with a carb. 5)Most of the aftermarket stuff is patterned off the factory systems and still trying to meet emissions. 6)It would not surprise me at all if an aftermarket EFI system, that was design from the ground up to make power and not care about emissions, made more power than a carb.

1)That's why manifold designs(wet vs dry) are different.The amount of air an engine can pump IRRELEVANT to the fuel system.
2)And yet,it(the carb) still makes as much(or more) HP as FI.Go figure
3)Factory EFI was designed for emissions-PERIOD.
4)Yes-it does.Look at all the Viper,Vettes & such.But we aren't talking about factory-are we?
5)False
6)Too ridiculous to respond to.

[Cobrabill]

Originally Posted by stuartb

For me it was an easy choice, EFI was the way to go with a change in altitude of about 5000 ft. on my normal drives.

I was going to mention "your" situation but i thought it would be a digression of sorts.But that is one advantage of the "correct" FI system.

[Great Asp]

Bill,

1) Do you know what a T-bone looks like? "Sure.Another non-sequitur would be nice" Do I have to tell you how to look?

2)When someone says that let me know. "You did.But not in so many words." Thanks clearing that up, you are right, I'm sure

3)Gee thanks. I guess a Volkswagon would have been more practical. I'll have to re-think this whole Cobra thing E "Don't get all worked up fer christ sakes.If WE were the pratical type,this board would be a ghost town.And the last time i looked,the FI/carb debate wasn't Cobra specific." I didn't think it was a big leap to the statement I made based on your comments.

E

[olddog]

Bill I likely agree with you on more things than I would disagree.

I take it that your point of view is that if the air fuel ratio is 12.5:1, it makes absolutely no differance how it got there. The fuel system is irrelevant. All that matters is how good an air pump is the engine. Not trying to put words in your mouth, but that is my interpretation of what you said.

If you could conveniently totally seperate AFR and flow, I would absolutely agree. However the fuel delivery can affect the air flow into the pump (engine). Look at a dual plane verses a signle plane intake or what a carb spacer can do to flow. Now is it so hard to fathem that where the fuel is introduced could impact how much air can flow into the engine?

Last I was on Edelbrocks web site they were advertising several of their engines with both carb and EFI, and they claimed the EFI version would make more Hp. Ridiculous I guess.

Edit: I just checked Edelbrocks site and it no longer lists different Hp for carb verses EFI. Don't know what to make of that.

Edit 2: Well it depends on how you get there. If you look at the chevy 555 cid Pat Musi engine 650 hp is the carb version and 675 hp is the EFI version. Same cam and heads. Different induction systems. EFI torque looks to be higher both low and high rpms. Both engines peak 650 lb-ft @4500 rpm.

[ZOERA-SC7XX]

I don't wanna highjack the thread, but how would the Dynatek EFI improve a medium HP engine like mine (428 10:1 CR, iron heads, maybe 400/425 HP). I like the idea of improved torque and HP, but at 5G's, it ain't cheap. Any thoughts?

[Barry_R]

I have run the same 505 inch, 676 horsepower FE engine on a dyno with both multiport EFI and a carb. Documented in Hot Rod magazine in 2004.

Same intake - a converted Dove single four barrel. We never touched a thing on the package - unbolted the throttle body and bolted on a 950HP, unplugged the injector wiring from the harness and hooked up fuel to the carb.

Based purely on airflow the EFI throttle body should have won. It didn't. A statistical dead heat - but the carb had single digit higher peaks on both torque and horsepower.

Testing done at Wheel to Wheel Powertrain - at the time one of the foremost EFI tuning facilities in the country. The EFI is better at almost every non-WOT and transient driving parameter - but peak power is not one of them.

[Great Asp]

Originally Posted by ZOERA-SC7XX

I don't wanna highjack the thread, but how would the Dynatek EFI improve a medium HP engine like mine (428 10:1 CR, iron heads, maybe 400/425 HP). I like the idea of improved torque and HP, but at 5G's, it ain't cheap. Any thoughts?

Rather than us telling you how, call the guys at DynaTek and ask them. They gave me hard dyno numbers to back up their claims. I think the big incease would be in torque.

Your right, it's not cheap.

I have not taken delivery of my car (yet), so I can not speak of how well it drives. But I will be posting late Friday night on my build thread as I am going to Plano to see the chassis dyno, and drive the car.

E

[Fordzilla]

Originally Posted by Barry_R

Based purely on airflow the EFI throttle body should have won. It didn't. A statistical dead heat - but the carb had single digit higher peaks on both torque and horsepower.

Very Interesting. Thanks Barry

[olddog]

Originally Posted by Barry_R

I have run the same 505 inch, 676 horsepower FE engine on a dyno with both multiport EFI and a carb. Documented in Hot Rod magazine in 2004.

Same intake - a converted Dove single four barrel. We never touched a thing on the package - unbolted the throttle body and bolted on a 950HP, unplugged the injector wiring from the harness and hooked up fuel to the carb.

Based purely on airflow the EFI throttle body should have won. It didn't. A statistical dead heat - but the carb had single digit higher peaks on both torque and horsepower.

Testing done at Wheel to Wheel Powertrain - at the time one of the foremost EFI tuning facilities in the country. The EFI is better at almost every non-WOT and transient driving parameter - but peak power is not one of them.

Barry - I'm not trying to argue the point, but would like to learn from your extreamily interesting (to me) test. Was the intake manifold dual plane or single plane? Was there a measure on the AFR to see if that could explain the difference? Was the timing exactly the same?

I have a MassFlow on a 347 stroker, which uses an Edel Vic Jr carb intake with EFI bungs welded into the ports. MassFlow claims that it will only work on a single plane intake, and that with no fuel in the manifold that the typical poor low end torque does not happen. Maybe, but it seems to me that an intake designed for a wet air stream would not work as well as one designed to run dry from the get go.

Also the webber look alike with individual throttle plates that close to the head ports is a whole different ball game.

[Barry_R]

Single plane 4150 flange

A/F was monitored in both cases via the O2 sensors in the exhaust.

Timing was identical - the FAST system was still plugged in and running ignition and some data could still be retrieved to back up the dyno - obviously not fuel.

The Weber deal would indeed be different. Most if not all carbed Weber deals suffer from inadequate airflow - no shared volume from the non-existant plenum. Ford's abbreviated Boss 302 IR effort used two Dominators. Anything that adds airflow in an IR package will show a gain - but the gain is because of the additional air and not the management system.

[cobrarkc]

Ok I am a little confused here. If carbs are so good why aren't they using them in Top Fuel and Formula 1?