NA Bridge port/ Peripheral port Dyno sheet
01-14-09, 02:10 PM
#51
His arguemnt is a valid one, but we're compairing apples to oranges again. Sure the choke is a negitive thing when it comes to flow. A choke is exactly that a flow restriction, but there is a velocity increase which is benificial that his arguement ignores. I'm not saying that a 48IDA with 38mm chokes is going to make more power than 48mm ITB's because that's absurde, but a 51.5 IDA with 48mm chokes will allways make more peak power than a 48mm throttle body. That's all I'm saying. With equal flow a carb will make more power than FI.
09-17-09, 09:16 PM
#52
I have seen carbs ICE up bellow the carb bowl due to increased flow....so bad that we had to install heater style sheilds to bring heat from header up to carb....this is due to venturi effects which speeds up fuel/air creating a frost not due to more air initially but because of the nature of a venturi more air speed at the exit should and would create more air flow at the opening...
EFI is ( supposed to be easier) than carbs to set up, but that is just based on operator experience..I have raced /built and tuned PP with webers all my life...I just got inot a haltech EFI project and within 2 weeks of head pounding and pulling hair I am about to try a turbo blow through!!!! I hate EFI standalones...But i am sure there are guys that only know EFI that hate CARBS!!!!
my point is that in the right hands any one of these systems would be a lethal and powerful system...but it is all about your goals and your budget, and of course your experience!!!
that said , I am going to try a IDA blown trhough...never did that before any ideas or advice? I am seriously getting rid of my haltech..it blows...
how do guys control timing under boost these days? MSD? or just running less advance on set up?
BTW this is the perfect thread !!! it was my first search on the topic and should be stickied in my opinion!!!!
ohhh my set up is 13 BP with 91 high comp rotors and RA seals
EFI is ( supposed to be easier) than carbs to set up, but that is just based on operator experience..I have raced /built and tuned PP with webers all my life...I just got inot a haltech EFI project and within 2 weeks of head pounding and pulling hair I am about to try a turbo blow through!!!! I hate EFI standalones...But i am sure there are guys that only know EFI that hate CARBS!!!!
my point is that in the right hands any one of these systems would be a lethal and powerful system...but it is all about your goals and your budget, and of course your experience!!!
that said , I am going to try a IDA blown trhough...never did that before any ideas or advice? I am seriously getting rid of my haltech..it blows...
how do guys control timing under boost these days? MSD? or just running less advance on set up?
BTW this is the perfect thread !!! it was my first search on the topic and should be stickied in my opinion!!!!
ohhh my set up is 13 BP with 91 high comp rotors and RA seals
09-18-09, 12:19 AM
#53
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,844
Received 2,605 Likes
on
1,848 Posts
i should trade you for my weber... instead of pushing a button to tune, its gee lets order this this and this, and wait for it to come in.....
i know this is off topic, but since the PP is such a beast i might have to dyno tune it, so i might have a sheet before the end of the year
i know this is off topic, but since the PP is such a beast i might have to dyno tune it, so i might have a sheet before the end of the year
09-19-09, 11:17 AM
#55
maybe to you rotaygod..being a GOD and all this is very petite..lol........but i actually am enjoying the discussion alot...and I am sure many others too...maybe you can shed some of your godly wisdom on the subject?
i know your going to vote for standalone..over carb right...but staying on point have you seen any comparable dyno sheets to support the advantages of either?
not looking for which is easier or better now .............just if there are any dyno proofs that show major gains in similar builds..
repect to all rotary gods out there
henry
i know your going to vote for standalone..over carb right...but staying on point have you seen any comparable dyno sheets to support the advantages of either?
not looking for which is easier or better now .............just if there are any dyno proofs that show major gains in similar builds..
repect to all rotary gods out there
henry
09-23-09, 02:16 PM
#56
The Doctor
iTrader: (1)
Join Date: Apr 2008
Location: Cedar Rapids, IA
Posts: 1,185
Likes: 0
Received 0 Likes
on
0 Posts
Of my 4 runs, my best was 175 and worst of 166.
Of his 4 runs, his best was 173 and worst of 158.
My mods:
Holley 660 with changed jets
Cut jaytech intake
Homemade 2' to 3' collected exhaust
GSL-SE fuel pump (not regulated)
His mods:
TB mod
CAI with aluminum intake box
Walbro 255
Rtek 2.0
I'm not quite sure what your talking about because carb is proven over and over again to net higher hp than EFI setups for reasons already stated above. How can you argue with computer results...
It's like pissing into the wind...
09-23-09, 02:36 PM
#58
The Doctor
iTrader: (1)
Join Date: Apr 2008
Location: Cedar Rapids, IA
Posts: 1,185
Likes: 0
Received 0 Likes
on
0 Posts
Whops. Its a RB header & presilencer, Bonez cat, and some aftermarket catback that he doesn't know the name of. It came with the car. He pretty much bought it with all the mods and I went with him to get it tuned where I put down better #'s than him.
The stock turtle would make his car put down like 150-160 tops, lol.
The stock turtle would make his car put down like 150-160 tops, lol.
09-23-09, 03:11 PM
#59
Really? Because I ran back to back dynos with my S5 N/A carb'd with my friend who has a S5 N/A with a Rtek and consistently put down better # than him. On a block with 130k+ none the less!
Of my 4 runs, my best was 175 and worst of 166.
Of his 4 runs, his best was 173 and worst of 158.
My mods:
Holley 660 with changed jets
Cut jaytech intake
Homemade 2' to 3' collected exhaust
GSL-SE fuel pump (not regulated)
His mods:
TB mod
CAI with aluminum intake box
Walbro 255
Rtek 2.0
I'm not quite sure what your talking about because carb is proven over and over again to net higher hp than EFI setups for reasons already stated above. How can you argue with computer results...
It's like pissing into the wind...
Of my 4 runs, my best was 175 and worst of 166.
Of his 4 runs, his best was 173 and worst of 158.
My mods:
Holley 660 with changed jets
Cut jaytech intake
Homemade 2' to 3' collected exhaust
GSL-SE fuel pump (not regulated)
His mods:
TB mod
CAI with aluminum intake box
Walbro 255
Rtek 2.0
I'm not quite sure what your talking about because carb is proven over and over again to net higher hp than EFI setups for reasons already stated above. How can you argue with computer results...
It's like pissing into the wind...
09-23-09, 03:17 PM
#60
The Doctor
iTrader: (1)
Join Date: Apr 2008
Location: Cedar Rapids, IA
Posts: 1,185
Likes: 0
Received 0 Likes
on
0 Posts
I'll see if I can track down the papers for it but I'm sure no one wants to see stock port N/A sheets.
09-23-09, 05:04 PM
#61
The Doctor
iTrader: (1)
Join Date: Apr 2008
Location: Cedar Rapids, IA
Posts: 1,185
Likes: 0
Received 0 Likes
on
0 Posts
Hmmm... Looks like the back yard mechanics are having non of this mumbo jumbo science talk, eh? I sometimes think some people like carbs because they will at least work even if tuned poorly and that creates something to talk about. EFI doesn't work well unless you tune it right and that takes understanding the whole thing a lot more scientifically. You have to be at least somewhat good with graphs and tables and all that. Perhaps a bit much for some?
Saying that you and Joe went to the dyno and he had EFI and you had carbs and you made more power is what's called "anectdotal evidence". Its an interesting story or anecdote, but not very meaningful. Further, even if the comparison were done scientifically and yielded the same results for peak power, it only shows a 1.5% improvement in peak power and I assure you that the powerband of the EFI car would show a lot more power over a broader range and the carb guys would have to agree, since they've already conceded that argument in this thread.
I think that its far more convincing that nobody in road racing uses carbs. Deductive reasoning suggests its because EFI produces more power and has other benefits. I don't know who does use carbs these days in racing and of course no production cars have them. And, carbs are certainly no recently discovered secret to making more power. We all used nothing but carbs for as long as I can remember. When EFI became available, everybody switched.
Somebody added the observation that the reason racing teams don't use carbs is because they would have to rejet them for different tracks. Can anyone point to any article or writeup somewhere that in any way supports that? Racing teams used to do rejet their carbs for different conditions for the first 40-50 years of racing, when they had one tenth the budget and staff, and nobody ever complained. If carbs worked better, I assure you all the teams would be using them today.
Gordon
Saying that you and Joe went to the dyno and he had EFI and you had carbs and you made more power is what's called "anectdotal evidence". Its an interesting story or anecdote, but not very meaningful. Further, even if the comparison were done scientifically and yielded the same results for peak power, it only shows a 1.5% improvement in peak power and I assure you that the powerband of the EFI car would show a lot more power over a broader range and the carb guys would have to agree, since they've already conceded that argument in this thread.
I think that its far more convincing that nobody in road racing uses carbs. Deductive reasoning suggests its because EFI produces more power and has other benefits. I don't know who does use carbs these days in racing and of course no production cars have them. And, carbs are certainly no recently discovered secret to making more power. We all used nothing but carbs for as long as I can remember. When EFI became available, everybody switched.
Somebody added the observation that the reason racing teams don't use carbs is because they would have to rejet them for different tracks. Can anyone point to any article or writeup somewhere that in any way supports that? Racing teams used to do rejet their carbs for different conditions for the first 40-50 years of racing, when they had one tenth the budget and staff, and nobody ever complained. If carbs worked better, I assure you all the teams would be using them today.
Gordon
And their not used in big race motors?
09-23-09, 06:36 PM
#63
spoon!
Hate to break it to you sparky, but there's no carburetors in that picture. Tell you what, go between a Holley on a Jaytech manifold and a Holley pattern throttlebody on a Jaytech manifold. If you think comparing an actually decent intake manifold to an OEM one is a reasonable way to compare EFI and carburetion, you're nuts.
Hell, why am I bothering... oh well, screw it. I'm in the mood of beating my head against a brick wall for a bit.
Carburetors are actually pretty ******* interesting devices. I play with stuff built to SCCA EProd rules, so I have to run one... and so I'm working on understanding how it works.
Food for thought though... and this is all stuff you can find out on your own with some research. But an efficient booster venturi isn't vaporizing the fuel at high RPM; it's nebulizing it. The difference? Well no, you don't actually want it completely vaporized at that point in the intake tract; liquid fuel takes up a lot less volume so actually completely vaporized gasoline at that point means you're actually hurting your volumetric efficiency a bit. Bit of a balancing act because yeah, the vaporizing fuel does cool the intake charge a bit; Rolls Royce played with that on the Merlins back in the day. The thing is though that depending on where and how you inject fuel, you can get the same effect to any extent you want. Done a lot on sportbikes lately (all this talk of 'showerhead' injectors) and various race motors. Look at pics of where the old GTU / Camel Lights motors injected for example.
Part of the problem with carburetors from an efficiency point of view *is* the ******* venturis. Yeah, okay, the air intake charge is colder from the pressure drop too... simple thermodynamics. Except that the pressure goes back up after the venturi, for pretty obvious reasons... well, mostly up. Non-recoverable pressure losses in any restriction in the intake tract and that is exactly what venturis are. Restrictions. The other thing is that if you look at it from an energy balance point of view... for a while yeah, the intake tract is colder because of the pressure drop and the vaporizing fuel earlier than might be ideal. But because it's colder, voila, bigger heat differential, and more heat energy going into things. And if you think the gasoline injected on an EFI setup isn't cooling the intake charge at some point you're missing the point; it's still vaporizing at some point, otherwise it wouldn't even be able to burn.
Another point on the evolution of injection vs. carburetion... top level race cars stopped using carburetion in the *60*s. So no, it's not "becaue they would have to retune as they went to various tracks around the world and it's easier with EFI". They moved to Lucas / Bosch / Kugelfisher / Hilborn /etc mechanical fuel injection... because it worked better despite the headaches.
Hell, why am I bothering... oh well, screw it. I'm in the mood of beating my head against a brick wall for a bit.
Carburetors are actually pretty ******* interesting devices. I play with stuff built to SCCA EProd rules, so I have to run one... and so I'm working on understanding how it works.
Food for thought though... and this is all stuff you can find out on your own with some research. But an efficient booster venturi isn't vaporizing the fuel at high RPM; it's nebulizing it. The difference? Well no, you don't actually want it completely vaporized at that point in the intake tract; liquid fuel takes up a lot less volume so actually completely vaporized gasoline at that point means you're actually hurting your volumetric efficiency a bit. Bit of a balancing act because yeah, the vaporizing fuel does cool the intake charge a bit; Rolls Royce played with that on the Merlins back in the day. The thing is though that depending on where and how you inject fuel, you can get the same effect to any extent you want. Done a lot on sportbikes lately (all this talk of 'showerhead' injectors) and various race motors. Look at pics of where the old GTU / Camel Lights motors injected for example.
Part of the problem with carburetors from an efficiency point of view *is* the ******* venturis. Yeah, okay, the air intake charge is colder from the pressure drop too... simple thermodynamics. Except that the pressure goes back up after the venturi, for pretty obvious reasons... well, mostly up. Non-recoverable pressure losses in any restriction in the intake tract and that is exactly what venturis are. Restrictions. The other thing is that if you look at it from an energy balance point of view... for a while yeah, the intake tract is colder because of the pressure drop and the vaporizing fuel earlier than might be ideal. But because it's colder, voila, bigger heat differential, and more heat energy going into things. And if you think the gasoline injected on an EFI setup isn't cooling the intake charge at some point you're missing the point; it's still vaporizing at some point, otherwise it wouldn't even be able to burn.
Another point on the evolution of injection vs. carburetion... top level race cars stopped using carburetion in the *60*s. So no, it's not "becaue they would have to retune as they went to various tracks around the world and it's easier with EFI". They moved to Lucas / Bosch / Kugelfisher / Hilborn /etc mechanical fuel injection... because it worked better despite the headaches.
09-23-09, 07:47 PM
#64
It's all in the timing.
Join Date: Jun 2009
Location: Australia
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
09-23-09, 09:04 PM
#65
Welcome to the 21st century. Anyone using a carb anymore is either scared of efi (lazy) or too poor to use anything else. Then again carbs aren't exactly cheap if you are converting over a formerly fuel injected engine. Especially an RX-7. Then again the same people that complain that efi is too complicated who go carb still typically never get great results as they still try to use what someone else told them to use. Learn how to tune your own damn car or sell it to someone smarter!!! Sometimes they are happy based on recommendations but even then I guarantee that they are still not getting what they could out of it. As a tip, anyone reading this that has a Weber IDA or DCOE, look into cross jetting it. You'll find a couple more hp.
Race cars used to rejet at EVERY track. They'd even change between practice rounds and the actual race. Guess what? Fuel injected race cars are constantly changing their tuning too. Nothing has changed in that regards except of course that they have far more control over fuel and ignition, they're faster, cleaner, and more fuel efficient. Aside from that... A carb is a step backwards from fuel injection when it comes to technology. I could care less what drag racer from Puerto Rico has on his 6 second 17 lb rotary powered Datsun 510. If he had efi and it was done properly he could be making more power! That country is a testament to how fast mistakes and complete junk can be when it weighs nothing. That sentance should **** some people off but they'll get over it. Drag racing doesn't impress me anyways.
I can't think of a way to make a carb superior to good efi. I take that back. It wins on the grounds of simplicity. Unfortunately while simple is good, efi is still better!
Race cars used to rejet at EVERY track. They'd even change between practice rounds and the actual race. Guess what? Fuel injected race cars are constantly changing their tuning too. Nothing has changed in that regards except of course that they have far more control over fuel and ignition, they're faster, cleaner, and more fuel efficient. Aside from that... A carb is a step backwards from fuel injection when it comes to technology. I could care less what drag racer from Puerto Rico has on his 6 second 17 lb rotary powered Datsun 510. If he had efi and it was done properly he could be making more power! That country is a testament to how fast mistakes and complete junk can be when it weighs nothing. That sentance should **** some people off but they'll get over it. Drag racing doesn't impress me anyways.
I can't think of a way to make a carb superior to good efi. I take that back. It wins on the grounds of simplicity. Unfortunately while simple is good, efi is still better!
09-23-09, 09:26 PM
#66
LAZY? POOR? NOT SMART ENOUGH?
wow rotarygod, your pretty good with words....I woudl use a carb anyday and it has nothing to do with any of those small minded comments you made dude, it simply has to do with what I am comofrtable with and have knowledge of...
I am neither lazy since i work 15 hour days, nor poor, nor dumb, UNLESS of course a hon degree in automotive engineering is a easy push over degree ,
While I fully aggree with some comments such as ease of use once you understand it, and some people have the fear of efi, and that it is more fuel efficient than most carbs. I totally dont aggree with it being a waste of time, or a step backwards. A carb can be as efficient as efi, loook at old hondas that got 35 mpg back in the early 80s? the only thing is efi is superior in emmisions..and to some extent control...
what does it matter if a guy chooses carb to make same power as a guy who chooses efi? really? none in my book, more power to anyone who does it!!!
if your into racing cars power is power, who gives a crap how you get it!!!
further more it seems to me that any one that is actually endorsing efi is either a tuner or knows nothing about carbs because they are from this new generation of efi kids...my 2 pennies....
wow rotarygod, your pretty good with words....I woudl use a carb anyday and it has nothing to do with any of those small minded comments you made dude, it simply has to do with what I am comofrtable with and have knowledge of...
I am neither lazy since i work 15 hour days, nor poor, nor dumb, UNLESS of course a hon degree in automotive engineering is a easy push over degree ,
While I fully aggree with some comments such as ease of use once you understand it, and some people have the fear of efi, and that it is more fuel efficient than most carbs. I totally dont aggree with it being a waste of time, or a step backwards. A carb can be as efficient as efi, loook at old hondas that got 35 mpg back in the early 80s? the only thing is efi is superior in emmisions..and to some extent control...
what does it matter if a guy chooses carb to make same power as a guy who chooses efi? really? none in my book, more power to anyone who does it!!!
if your into racing cars power is power, who gives a crap how you get it!!!
further more it seems to me that any one that is actually endorsing efi is either a tuner or knows nothing about carbs because they are from this new generation of efi kids...my 2 pennies....
-
ouccchhh!
09-23-09, 09:44 PM
#68
-
Yes i agree with rotorgodd ,but lets not forget ,it all depends on budget ,and experience!For a street N/A screemers or low budget build carbys are not to bad!!!!!!!!!!!! Even some HI HP builds but has to be done right! Also prefrence ,EFI is by far your best bet to get the most HP & fine tuning,jet changin etc......As for PR drag cars not all are under weight !but pound for pounda hand full of them Island boys make **** work with very little!Proven fact,last your aplication should determine what set-up to go with ,i have a 13b-PP 58mm weber,Nitrious full body 2,278lb car 9.01@148mph consistent! 5.6@117mph 1/8mile
giving them EFI guys a runn for their $$$
giving them EFI guys a runn for their $$$
09-23-09, 09:57 PM
#69
as i said ..without trying to insult anyone in the process.....it is based on peoples own choice and preference...why are some people on here dead set on banging people down because they mention the word carburetor? I just dont get it? so what if someone wants to use a carb...did they pass a new law against it? nope dint think so......
anyway inspite of my efi ignorance I am not bad mouthing efi I am actually in the middle of a frustrating learning curve on halteck..lol so there I am nnot like the efi people on here that get all **** over what people want to use,,,...LOL
to each his own i say
POWER IS POWER !! DOES IT MATTER HOW I GET IT? NOPE!! POWER IS POWER!!!
anyway inspite of my efi ignorance I am not bad mouthing efi I am actually in the middle of a frustrating learning curve on halteck..lol so there I am nnot like the efi people on here that get all **** over what people want to use,,,...LOL
to each his own i say
POWER IS POWER !! DOES IT MATTER HOW I GET IT? NOPE!! POWER IS POWER!!!
09-23-09, 10:00 PM
#70
It's all in the timing.
Join Date: Jun 2009
Location: Australia
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
welcome to the 21st century. Anyone using a carb anymore is either scared of efi (lazy) or too poor to use anything else. Then again carbs aren't exactly cheap if you are converting over a formerly fuel injected engine. Especially an rx-7. Then again the same people that complain that efi is too complicated who go carb still typically never get great results as they still try to use what someone else told them to use. Learn how to tune your own damn car or sell it to someone smarter!!! Sometimes they are happy based on recommendations but even then i guarantee that they are still not getting what they could out of it. As a tip, anyone reading this that has a weber ida or dcoe, look into cross jetting it. You'll find a couple more hp.
Race cars used to rejet at every track. They'd even change between practice rounds and the actual race. Guess what? Fuel injected race cars are constantly changing their tuning too. Nothing has changed in that regards except of course that they have far more control over fuel and ignition, they're faster, cleaner, and more fuel efficient. Aside from that... A carb is a step backwards from fuel injection when it comes to technology. I could care less what drag racer from puerto rico has on his 6 second 17 lb rotary powered datsun 510. If he had efi and it was done properly he could be making more power! That country is a testament to how fast mistakes and complete junk can be when it weighs nothing. That sentance should **** some people off but they'll get over it. Drag racing doesn't impress me anyways.
I can't think of a way to make a carb superior to good efi. I take that back. It wins on the grounds of simplicity. Unfortunately while simple is good, efi is still better!
Race cars used to rejet at every track. They'd even change between practice rounds and the actual race. Guess what? Fuel injected race cars are constantly changing their tuning too. Nothing has changed in that regards except of course that they have far more control over fuel and ignition, they're faster, cleaner, and more fuel efficient. Aside from that... A carb is a step backwards from fuel injection when it comes to technology. I could care less what drag racer from puerto rico has on his 6 second 17 lb rotary powered datsun 510. If he had efi and it was done properly he could be making more power! That country is a testament to how fast mistakes and complete junk can be when it weighs nothing. That sentance should **** some people off but they'll get over it. Drag racing doesn't impress me anyways.
I can't think of a way to make a carb superior to good efi. I take that back. It wins on the grounds of simplicity. Unfortunately while simple is good, efi is still better!
^ + 1
09-23-09, 10:05 PM
#71
spoon!
