EFI over Carby???

[Blue23]

Hi

Probably a stupid wuestion but i am in mixed thoguhts.

i currently have a RA23 with an 18RG running Twin Webbers, i have been told that it could be worth my wild sourcing an EFI system and replacing my carbies, would this be a well off idea?

what can be the pros and cons of doing this?

also i have been told that there are two or three different Head set ups that can be placed on and 18RG, i am currently running a Yamaha head BUT are there TWO types one with a higher compression ratio?

any info would be great

cheers

[Joshstix]

What is your aim?

Without knowing what you want to achieve and the running state of the current setup it is difficult to advise on what is a good direction to go in. EG if you're after economy then yeah the EFI is likely to use less fuel but it's going to cost to do the work so probably not worth it. IF you're looking to make good power then the EFI could be good with an aftermarket computer but so could the carbs etc.

[jonathan yee]

hmmm....remeber when i had a big sucker 45webber on my mini. awesome sound.

think the pro's and cons come down to how much you wanna spend. like i guess you'd get improved fuel economy and better power perhaps thru a good and proper setup with quad throttle bodies but is it worth the cost and hassle? prob not.

think the later 18rg's came with EFI at some point and that system would be the easiest to fit and setup but being such an old design efi system prob wont net you the biggest of gains to warrant the cost and hassle of changing everything you've got there running smoothly as it is.

just my opinion tho. EFI would become more usefull the more you mod your eng ie: crazy high comp, lightened and balanced internals, P&P head etc.

[Blue23]

i have just ben looking around, in my opinion i love the carby sound and alot of my mates says "once you go carby you never go back". but i also have been loking into supercharging.

summernats last year, in the Gary Myers tent seen an 18RG Celica EFI system massive suppercharger and basically thought that i wouldnt mind doing that. but with an EFI system does this change it from an 18Rg to 18RGUE is that the only difference between the engine or are there more there?

i roughly pull around 79kw out of the 18rg with the carbs, does or can an EFI system boost the all round power out put, OR will i have to full on rebuild with everything gettin high comp ratios and everything?

[river]

Hi,

EFI will not get you any net power gains than carbs. The power curve may be better with EFI, but it will not make more power than the carbs.

To take advantage of EFI you need to spend a bit of money and get an inlet manidold, injectors, ECU, fuel pump and get it all put together and then tuned. It is not a trivial or cheap exercise.

The 18R-G came out in a few different flavours over its production run. The 18R-G and 18R-GR wer the first models and had the highest compression ratio and also had the highest output. The 18R-G has the 210 head and the 18R-GR has the 230 head. Next came the 18R-GU, which had lower compression ration and anit-pulliton gear on the carbs and it had the 250 head. The final verison was the 18R-GUE which had the 270 head (though I think some had the 250 head.. but I am sure someone will correct me) and EFI. It was a crude EFI compared to the ones you can get today.

The (approx) power outputs are:-

18R-G - 145hp
18R-GR - 140hp
18R-GU - 120hp
18R-GUE - 130hp

Check the head on your engine and see if it is stamped with 210, 230, 250 or 270. This will give you an idea of what you have. However, you can change the heads around. The 270 head has the best flow and biggest valves. The 210 head had the smallest valves, but it had the highest CR and the most agressive cams. So, you can sort of chop and change heads about.

There is no specific Yamaha head. The head of the 18R-G was developed for Toyota by Yamaha. Some heads are stamped Yamaha and others are stamped Toyota... but they are the same head.

If you are going to turbo your engine then the 18G-GU or better still the 18R-GUE are the engines to use, with their better head design and lower CR.

If you just want a nice NA sound and performance, then the 18R-G is the best.

seeyuzz
river

[RAd28]

I run an 18RG with twin DCOE 45 webers and I love it... I've considered going to EFI, but only if i could work out a cheap (really cheap) individual throttle body setup. I believe the benefits from EFI would be easier (cold) starting, and idle smoothness, and over all fuel economy, power will almost certainly increase with a good tune, but there's still plenty of performance applications where carbies are chosen over EFI because they're easier to tune on the cheap, it's just a matter of swapping/drilling jets, where as with EFI you need a laptop or hand controller at the very least to be able to tune at the track or in your garage...

Personally I'd say stick with the carbies... if you've got DCOE40's then upgrade to 45's you'll notice a pretty distinct difference just there.

[Blue23]

cheers all

i guess what i want to get is more power but naturally aspirated power i dont want to head down to turboing or supercharging (that will be at a later date)

yer well i love the carbies, from the word go when i bought the celica and she was running like a bag of poo, until i spent some time (and alot of money) and got her tuned she is running pretty mean at the moment.

so from what im gettin here and what i have re-searched, there are a few more things that i can do with the set up i have now. would my best option be to see what head i am currently running, lets say that i have the 18R-G head (210), what would be the best head to source and replace this one with? because i am gathering higher compression ratio more power (sorry i no these are a bit of noob questions but when it come to heads i dont know much im just trying to suck it all in).

now also are there any advantages of gettin a port and polish done? when i had my car tuned i had my carbies over hauled, floats, cam, basically everything rehashed and she is running better now, but was wondering whether or not a port and polish is really worth the time and money?

[parrot]

If it is a daily driver then EFI is great. Start first time every time, smooth power delivery etc. But that is assuming you have set it up properly. If you go factory you need to ensure you have all the relevent sensors, idle up etc and that they all function as they are meant to, which may mean sourcing or making appropriate looms. My experience is with 4AGE's on factory computers. It runs so much better with every sensor operating and taliking to the computer via the correct looms. The disadvantage is that you will potentialy be limited by fuelling maps and camshaft duration.

You could also go aftermarket. Either way it will cost plenty.

I once had a hot 2T with twin webers and I grew a bit tired of cold start problems, having to turn back dizzy's to start it and so on.

Nowadays, I have EFI for everyday, and I will be building up a carbed 3TG for my fun car. If you want to sell your solexes, let me know!

The number one rule is that the EFI needs to be properly sorted, but then so do carbs.

[Talasas]

Yeah pretty much everything has been covered here, carbs still offer an excellent way of making narrowband power but the issue will always be they operate within a narrow range of engine conditions and ambient temperatures (albeit well).

If you want the reliable all-weather starting of a factory EFI system, you will have to make sure you research the setup well, I've found many of those complaining about poor EFI setups are results of poor setup and/or poor tuning (no different with carbies really). The first rule is always never go overkill with the fuel system, people seem to believe that somehow a bigger carby/injectors/everything without any further work will yield awesome power when in fact it's often detrimental to performance and reliability.

It's not done often where they are tuned well for daily driving, those that achieve that with aftermarket tuning deserve a pat on the back.

[Blue23]

I run an 18RG with twin DCOE 45 webers and I love it... I've considered going to EFI, but only if i could work out a cheap (really cheap) individual throttle body setup. I believe the benefits from EFI would be easier (cold) starting, and idle smoothness, and over all fuel economy, power will almost certainly increase with a good tune, but there's still plenty of performance applications where carbies are chosen over EFI because they're easier to tune on the cheap, it's just a matter of swapping/drilling jets, where as with EFI you need a laptop or hand controller at the very least to be able to tune at the track or in your garage...

Personally I'd say stick with the carbies... if you've got DCOE40's then upgrade to 45's you'll notice a pretty distinct difference just there.

well on closer inspection this afternoon it looks like im sitting on the 270 head with the DCOE45's. So..... if i could source a 210 head would this give me higher compression ratio? on that is there any room to upgrade internals, eg, cams, pistons ect?

[RAd28]

From what i've read in the past the 210 head is of lesser quality in the port design compared with the 273 head, and as river mentioned, smaller valves which means a more responsive engine, but less top end.

To be honest, i think you'd be dissappointed if you went to the effort of changing heads alone... you almost certainly won't get a notable power increase... if you notice anything it would probably come down to other things you'll play with in the process of swapping heads...

again, from what i've read (not 1st hand experience) Port and polish are worth doing if you've got the head off, but not if your gonna take the head off just to do it... I'm planning on embarking on a top end rebuild in the not too distant future, part of the plan is to fit new timing chains and guides, do a port and polish, head shave maybe and drop in some hot cams. That i expect will yield some nice gains. In your case, i'd suggest checking out your bottom end because the 18RG cam with several compression ratios (governed mainly by the pistons). from 8.2:1 up to 9.7:1. probably more again if you consider the ones that started life as an 18R-C. I've only driven my 18RG which has 9.7:1 bottom end and i love it, but i don't know how much of a difference a lower comp ratio engine would see...

Check out the 18RG thread "life and times of a tractor engine" HERE. There's not much info about the 18RGs that isn't on that thread. It'll answer all your questions and probably a few more...

[Brad-KE35]

EFI for lyfe.

[RA23]

well on closer inspection this afternoon it looks like im sitting on the 270 head with the DCOE45's. So..... if i could source a 210 head would this give me higher compression ratio? on that is there any room to upgrade internals, eg, cams, pistons ect?

You have already got a head with large valves, stick with it. Swap pistons for higher C/R (from 210 engine - hard to find, or aftermarket)
Read through the 18RG thread, there is good stuff there.

[river]

Hi,

Agreed. If you got a 270 head then keep it, as it was the last of the heads, and had the best features. Besides, 210 heads are getting very hard to find.

Maybe shave the head a fraction and, as mentioned, put in higher comp pistons to get the CR up to 9.7 - 10:1.

You call always try some more agressive cams. I'd like to know how 210 cams go in a 270 head engine. It would give you the best cams with the best head, but I am not sure if you'll notice a huge difference.

Furthermore, if you get too aggressive with the cams then you'll find the engine rather lethargic at lower revs, and this detracts from the drive-ability of the car. Sure, if it is for track work or hill climbs, then you can have an angry NA 18R-G, but for general road use you need to compromise so it is more docile for the daily haul.

The carbs you got are plenty big enough for what you want, and some more. So, you could always get the engine re-bored out to 2.2litre. Your carbs will be fine with this size, but it is not cheap to get this work done, plus new pistons to suit.

The next step is to then stroke it, which will get you from 2.2litre (assuming you bored it out) to 2.4litre. Your carbs "should" be fine with this size, but may need to go 48mm. Stroking means you'll need a 22R crank and 16R rods. The 22R crank isn't a problem but 16R rods are like hens teeth. I do not think the performance gain, in stroking, is worth the cost - especially for NA engine.

Also, as mentioned, both EFI and carbs need to be set-up properly. EFI, once set, shuold be fine for ever, assuming sensors and injectors etc do not fail. Carbs require constant re-tuning and fiddling. I love both for that very reason. I like to play and tune and tweak the carbs and it is fun to get them singing perfectly, but it takes time. EFI is good because if the induction system is all too technical for you, then having it set and forget is a great bonus. I can assure you, that most carb problems stem from poor tuning, as a well tuned set of carbs will start your car in the coldest and the hottest of weather, and run without mishap or problem through the entire rev range. But, the carbs need to be kept in top tune to do that. Many people cannot do this, so resort to EFI, and I don't blame them because tuning all those carbs is a dying art and takes some skill. But... it is fun.. tuning them.. sort of like working on an old steam engine.. there is something nostalgic and charmingly old school.

However, as much as I love carbs, the only way you'll make a lot more power and have an engine that will deliver power across a large rev range, is to go turbo - which means you'll need injection and an ECU. And, it will cost less than spending huge wads of money on an NA engine. That's why I have a NA 210-head 18R-G and getting a turbo'd 270-head 18R-GUE, so I can have the best of both, but using the same classic engine - the indefatigable 18R-G.

seeyuzz
river

[Blue23]

well thankyou all very much, i really appreciate the help.

i have been looking through that other thread and theres is some good information there, thanks.

im not looking to go all out nuts for a NA 18RG, from what i have read it is alot of $$$ for not a great big bang. but i would just like to get it a bit snappier, so from what you guys have said i might look into a more aggresive cam and up grade the pistons.

so can an 18RG be turbo'd? is this worth it? i was always under the inpression that they couldnt be turbo'd? i have seen a suppercharged one but never a turbo'd


cheers