Carbie 4AG

[flamingheads]

Just wondering about the benefits and drawbacks of twins carbies on a 4AGE if theyre tuned properly.

[Dorio86]

Benefits:
Less wiring
If your changing engines 4ac -4ag , its cheaper than converting to EFI


Cons:
More fuel consumption
Regular tuning (you might want to use bike carbs)
Can be a pain to drive through traffic


As they say "OLD-SKOOL"

[Monster]

One of my mates is running twins on his 16v, hes found that fuel consumtion isn't as bad as everyont makes out, but the tuning is... you have to retune them evertime you change altitude so yeah.
Also, putting twins on a EFI engine is very illigal (in NSW anyways)
Linkages can be almost as expensive as getting a manifold, which arn't to hard to find, but speaking from first hand... they are very cool and quick

[decoyslikecurves]

CAN be cheaper if you're lookin at going bigger cams, ported, polished etc etc.


they sound hot.

[flamingheads]

Are there any performance benifits?
And how often do they have to be tuned and what kind of altitude changes do they have to be tuned for?

putting twins on a EFI engine is very illigal (in NSW anyways)[/b] Does anyone know if its the same in QLD?

Can be a pain to drive through traffic[/b] How so?
Also the E in 4AGE is efi isnt it? so would that make it a 4AGC?

[Dorio86]

Originally posted by Loki Boyracer@Dec 5 2005, 11:14 AM
One of my mates is running twins on his 16v, hes found that fuel consumtion isn't as bad as everyont makes out, but the tuning is... you have to retune them evertime you change altitude so yeah.
Also, putting twins on a EFI engine is very illigal (in NSW anyways)
Linkages can be almost as expensive as getting a manifold, which arn't to hard to find, but speaking from first hand... they are very cool and quick
I did not say that the consumption is bad
I said that theres more fuel consunption

I did not say putting twins on EFI
I said that, a 4ac is carby and converting it to 4ag costs around an extra $700 to $900 for all the EFI wiring, but you can run without EFI by installing carbs.


Carbs sound great, but a high reving engines with a Sports injection KIT sounds allot better.

[flamingheads]

The engine Im thinking of is
100kw 4AG
rebuilt to include a ported and polished head
balanced crank and conrods
high compression pistons
electronic fuel pump
Ivan Tighe racing cams
custom made tuned length extractors
twin 42mm side draft Webbers

Apparently it revs out near 9000rpm.

[Dorio86]

You will get more horsepower out of 4ag with this

http://www.toda-racing.jp/product/onemake_e/4ag/4ag-10-2.jpg

[Monster]

I did not say that the consumption is bad
I said that theres more fuel consunption

I did not say putting twins on EFI
I said that, a 4ac is carby and converting it to 4ag costs around an extra $700 to $900 for all the EFI wiring, but you can run without EFI by installing carbs.[/b]

Chill dude, I wasn't having a go.

42mm? Try to find 45mm!!!

Performance benefits, about the same as a well tuned quad efi... the biggest drawback is that in a locked curve, the power band is extremely narrow, so a computer to run the advance can be quite expensive... so in the end, you might as well go quads on EFI

Check this out: Link... (http://www.ae86drivingclub.com.au/forum/index.php?showtopic=1628)

http://www.ae86drivingclub.com.au/forums/emoticons/laugh.gif

[Monster]

I know the intake has alot to do with the HP, but wouldn't the engine specs dictate the HP output?

[Black_Hachi]

I recon that setup you are after would be sweet as. My first car was a KE30 with a worked 2TG motor, bored, stroked, big cams, port n polished, big valves, balanced with twin 45 webbers.
Get someone decent to tune your carbs, they can also trick them up to make them run better. You will notice the power loss in hot weather. On a chilled summer night you will notice more power and awesome throttle response. I remember coming home from the coast at like 3am and popping the bonnet having one side of the engine bay cool with the carbies ice cold and the other side hot from the extractors.
You will need another fuel pump and a regulator. Yes, you will go through a bit of fuel but it all depends how u drive it.

[Bustin_86]

i was looking at doing it, but i decided not to after having a chat with Loki...

Its a nice idea, but it is NOT a cheaper conversion than EFI, for a engine with all the loom and ECU i am paying around $500, granted that is cheap, but there are bargains out there....if i wanted just a "bare" engine it would still set me back around $400 from the extent of my knowledge...then you have the carbs on top of that ( around $300 i have found) and linkages....manifold....When i was talking to Loki, i think he also said that you would need some sort of spark controller, so in essence you would still have a partial computer controlled car....once again, not to sure if this is all right, but this is just what i have found trhough my research and what i can rememeber.

Personally, i found that staying with EFI and buying some ITB's is a much better aproach, it is slightly more expensive in the short term, but if you dont know how to tune a carby you will be constantly forking out for tune's etc....and with EFI you will have the better consumption etc. Also, the ITB's will ( i think?) make more power, and along with the aftermarket ECU, will basically kick arse http://www.ae86drivingclub.com.au/forums/emoticons/tongue.gif

I may not be right....but thats just my take on it mate, hope it helps!

[nightdevil]

i was very surprised with Johns car. We raced up hill (no corners) to like 0 - 130 with the same final gear (4.3) and it was even as. If anything he had better pick up

[timmeh12]

i will settle this for everyone...

my bigport 4AG has a bit of work done to it (no cams), and has a set of 45mm sidedraft dellortos. with a locked timing curve my car make 100hp@ the wheels. with a timing curve with some advance, the engine will open up an extra 30hp. thats not bad for a very first gen 4AG. i drove this engine before it was rebuilt and worked, and my old 4AC was better... my engine also has an extremely flat torque curve and very progressive power. the engine picks up at any rpm.
regardless of whether it's efi or carby, if there is a seperate throttle body for every cylinder, than it will always make more power than a single throttle body. the difference in peak power output between efi and carby is little to none, the main difference is the driveability... a street car will always be better with efi because of it's tunability, but if it's a racecar where you're at full throttle all day it seriously makes no difference. let me say it again... NO DIFFERENCE IN PEAK POWER. it depends how the engine/intake/exhaust is setup as to how the engine makes its power.
as far as costs are concerned, carbies will be cheaper to set up depending on how you approach it, and how cheap you can find carbies for. but if you cut corners efi can be done for the same price. don't let loki put you astray on the cost, i have all my reciepts. to make a guess the carby setup cost me around $1200, but that was with the carbies reconditioned and rebuilt. there are more bits involved with efi, carbies are a hell of a lot simpler.
one myth about carbies and how they go out of tune... thats not necessarily true at all. i know many will disagree, but if they are set up right the first time, you won't need to touch them again. i can attest to this, my engine builder who tuned the car is GOD. the main problem is, not many people know how to set them and jet them correctly, hench never in tune. and when people fiddle with them or tune by ear, they tend to go further off the mark. my engine runs great all the time.
i have a locked curve which is bad becos i'm still using the 4AG dizzy which is elec. ignition and i have to use a module to get the engine to run. if i want, i could use a computer to run the ignition, but another option is to modify the 4AG one, to a mechanical advance, or modify a magna distributor to fit. that will set you back maybe $300. so there is an expensive way of doing things and a budget way.
take it from someone whose done this - if you want power it doesn't matter if it's efi or carbies. just make sure the intake diameter is a minimum of 45mm and don't go anything smaller, you'll just be holding yourself back. if you go quad throttles or twin carbies make sure you do other stuff to the engine as well, to compliment the engine. i drove a standard 100kw with 20v quadies, and it only sounded good. didn't go well at all...

my engine goes FREAK'N hard, even with the locked timing curve, and the throttle response is nothing but amazing. i definatly didn't go carbies for the cost, as i've spent close to $7K on my engine. the carbies are just one element that makes the engine perform. i seriously find my engine very satisfying.

so there.

[flamingheads]

So youre saying that the twin 42mm Webbers will be better than the standard efi but they should be 45mm for their full potential and that they should give similar performance to the quad throttle bodies, with all the other stuff in the engine, right?

[OBE353]

interesting thread, i am still waiting to put my motor in due to finances but it is a 7 rib block with ported n polished big port head, been re-honed, ringed all new internals basically, custom manifold with twin solex sidedrafts. I am good friends with the engine rebuilders who work next door to me (we do work for eachother) and they built the motor for a kit car they r goin to race but restrictions in the racing catagory wont allow this motor so i got it for 1500 i no people r getting EFI versions for less than half the price but considering it came with 4 into 1 tuned length extractors, alternator and dizzy and warranty i think its a steal. I'm also assuming it shuold b able to beat quad throttles....not sure though as i havnt driven it yet but it will b quick.

[mattysshop]

just like to add that 45mm carbs, and 42mm carbs.. brand new there like 1G a Pop..and you have to choke them down to at lest 35mm anyway.. then a manifold...tuning..don't forget the stand alone electronic ignition you must have to sort out from scratch.. i have looked at this option..best in my opinion to go efi.. i have 43mm silvertop qauds on mine.. thats 43mm at the smallest point..factory ecu..and she idles like a stock corolla.. http://www.ae86drivingclub.com.au/forums/emoticons/smile.gif tap the loud pedal and the response is phenominal!!

[Monster]

don't let loki put you astray on the cost, i have all my reciepts[/b]

Yeah, thanks John. What I was getting at is that people are miss led into thinking that simply because the technology is older than EFI or the fact that there is no computer needed (techniclaly) that it is a cheaper option than quads to EFI

[timmeh12]

yeah thats right 'flaming heads'. to give you an idea, the N2 racing hachis used 48mm sidedrafts with 41mm venturis, which are pretty damn big! that was to make big power high up in the rpm tho. i'm talking 220hp out of a 1st gen bigport in n/a form, revving up to 10,000rpm.
with 45's, going to a 35mm venturi will produce a lot of air velocity to give you strong low end power. but a 40mm with a 35mm or smaller venturi will give you less velocity compared to the 45's due to the volume of air being sucked in, hench less potential for power. anything smaller than 45's and you're holding yourself back. the same if you don't do any additional work to the motor. you'll have this mad motor with a totally non-restrictive intake, but becos the motor isn't up to pace with the intake, it won't be efficient and again you'll be holding yourself back.

everything will cost you money, and brand new carbies are very expensive... but a custom quad throttle efi can be just as expensive. it really depends on how you source your bits as to how much. pretty much everyone goes efi, and there's nothing wrong with that. but there is nothing wrong with carbies either.

it is really something that you have to be comfortable with. if you're umming and ahhing, just go efi. it'll be easier to putt around in on the street.

obe353, engine sounds like it'll be awesome!

i wish i could show everyone what my engine was like... my car is f***ed at the mo... frikk'n wet corners... frikk'n barriers...

[mattysshop]

thats my setup.. runs suprisingly great, with factory AE82 ecu and injectors..no piggyback anything..revs like crazy and responsive like all hell..

[mattysshop]

thats my setup.. runs suprisingly great, with factory AE82 ecu and injectors..no piggyback anything..revs like crazy and responsive like all hell..all up..the technotoy tuning manifold.. was $250 USD..the silvertop 20V quads were $200AU..the ecu etc i already had, but you can get from any wrecker or someone off here for no more than $100.. someone to wire it up..varies between $200-$300..some vaccume lines and t-peices...away you go!

Matty

[crazy86]

Originally posted by Mattysshop@Dec 6 2005, 11:34 PM
the ecu etc i already had, but you can get from any wrecker or someone off here for no more than $100..
What do you mean, It uses a stock 20v ecu? I thought you would have to go aftermarket?

[mattysshop]

nope..i am using a stock ADM AE82 rolla ecu..nothing special..it's all in the setup..you do it like me and it works just fine.. http://www.ae86drivingclub.com.au/forums/emoticons/wink.gif thats the way there running at the moment..no air filters or box even http://www.ae86drivingclub.com.au/forums/emoticons/smile.gif

the motor is a smallport motor with heaps of port work, and high compression..with quads.. and yes it runs like a dream on the factory AE82 bigport ecu.. don't worry, i have proven many people wrong, and suprised alot more http://www.ae86drivingclub.com.au/forums/emoticons/smile.gif

[Monster]

Can anyone say... Vaccum Chamber?

[mattysshop]

i can..but the way i have hooked mine up, it doesn't seem to need one!

[eastcoastdrifter]

Shinji Minowa uses a FCR Carborator (from a motorbike) for his 4AG