Just how far can you go with a 2TG?

[river]

Hi,

Carbies are more of a compromise than EFI. A well tuned EFI setup will always out perform a well tuned carb setup. If you take DCOE webers for example the compromise starts when you choose a venturi size. To get good bottom end drivability you have to sacrifice top end airflow. Then consider the weber has three main "points" it can be tuned for. Idle, transition and the main jets. A good EFI setup can be tuned down to every 10rpm or nearly an infinite number of points. Don't get me wrong I love my webers and wouldn't change them for anything. But for drivability performance and economy a well tuned EFI system is a better. Otherwise the F1 boys would still be using them.

I have no arguments regarding the carbs being more of a compromise than EFI. The point I was trying to make was that too many people have old, badly tuned carbs and seem to think that's the norm for carby engines, when it clearly isn't if the carbs are maintained and tuned. Yes, carbs are more finicky, they require more work, they go out of tune and require some effort to keep them running at their best. But they do perform well, and you can really get your engine singing when they've been tuned to perfection.

It comes down to what you like and what your perecption of old school is, and for me it's chrome bumpers and carbs.

For me, it's more fun and skill in keeping a nice set of carbs in peak tune than letting some processor do all the work. I certainly don't discount the marvel of engineering that makes the modern EFI so wonderful, and what it can do for an engine - but when your're talking about old 2T-G and 18R-G engines, I'll take the carbs anyday.

F1 is a racing application, and I am not discussing carbs for racing applications, but for street use.

I too apologise for the hijack. But it's aonly a little detour.

seeyuzz
river

[Billzilla]

Hi,

All this talk of driveability of EFI in regards to carbs is amusing.

It appears that the great majority of people think that carbs are useless and don't make your engine work. This is of course certainly true, if your carbs are not tuned. It's also true if your EFI isn't set up properly.

Do you really think that when these engines came out all those years ago that they spluttered, ran rough, and were poor to start, and all the other myriad of problems that people associate with carbs? Well, let me tell you, they didn't. If they did - and this is for all engines for street use, whether EFI or carb - the cars would be lemons, there'd be complaints and recalls and all sorts of consumer complaints.

These old carby engines are perfect when their carbs are properly tuned. They start and drive and rev like they were designed to.

I'll have to disagree with you there.
There is simply no way on Earth that any carby ever made will ever be half as good as a reasonable engine management system.
'Feel' has little to do with how an engine runs - you can still have the mixtures wildy out and the engine will still run just fine, you won't feel a thing. To state the obvious, with a decent ECU such as a Motec, you can extremely accurately schedule the fuel to get the mixtures to within 0.1 lambda at any point.
And it will compensate for altitude, air temp, (so air density in total) water temp, etc. A carby will do none of that.
A carby simply cannot have all the fine management needed to meet the require missions standards, nor maintain a good mixture (lambda again) under all conditions. You can adjust every variable you can think of, and many more. With options, they'll also constantly use feedback from the lambda probe to keep the mixtures more accurate again.
They constantly control the spark timing to within 0.1deg on each individual cylinder, again under all conditions with compensation tables.
There's so many positives to a good engine management system (which can be had for around $1,000 these days) that the only reasons you'd consider using carbies these days is if the rules require it, you're very poor, or are nostalgic.
The only possible advantage that carbies have is that they're more tolerant of changes such as cam timing and so on, that EFI is.

[jeffro ra28]

To state the obvious, with a decent ECU such as a Motec, you can extremely accurately schedule the fuel to get the mixtures to within 0.1 lambda at any point.

Sure its not .01 lambda?
pretty sure i can tune a carby to maintain .1 of a lambda no worries.

[river]

Hi,

For sure, I'm nostalgic.

I like to tinker and play with the carbs, and an EFI just doesn't hold that sort of appeal. I am not really interested in 0.1 lambdas, and for the way I drive and probably most street cars, it makes little difference. If I have a perfect automated fuel delivery system to make sure my engine is always getting the optimum mixture, spark and timing, then I may was well go the next step and put in a nice automatic gearbox that can change the gears at the perfect time for me, and then so on.....

To me, the whole vehicle owning experience means there's got to be things that need tinkering and adjusting and fiddling. I guess that's why I like the old cars, sort of like I prefer old steam engines over electric or diesel trains, and old piston engine planes as opposed to turbines, and assembler over Java... well, you get the picture.

seeyuzz
river

[Billzilla]

Sure its not .01 lambda?
pretty sure i can tune a carby to maintain .1 of a lambda no worries.

Yeah sorry, 0.01 lambda.
And no, you can't get a carby that good. Change the air pressure, air temp, water temp, etc, and they'll be off again.
This is why people still don't understand the difference thing - They say, and they're right, that a carby engine will make as much power as a EFI engine. Of course they will, but they will still never have as good a driveability under all real-world conditions.
A real example - A guy I know builds good Formula Atlantic engines. When I talked to him in 1998 he told me that the best power he got from Webers was 238hp, and the best on EFI was 242hp. That's close to dyno error, it's not a lot of difference.
But he said that he liked the EFI because he got 20hp MORE at 6,000rpm than with the carbies. You just can't get a carby to follow the bumps and dips in fuel flow than a twin-cam multi-valve engine has.

[Billzilla]

Hi,

For sure, I'm nostalgic.

I like to tinker and play with the carbs, and an EFI just doesn't hold that sort of appeal. I am not really interested in 0.1 lambdas, and for the way I drive and probably most street cars, it makes little difference. If I have a perfect automated fuel delivery system to make sure my engine is always getting the optimum mixture, spark and timing, then I may was well go the next step and put in a nice automatic gearbox that can change the gears at the perfect time for me, and then so on.....

To me, the whole vehicle owning experience means there's got to be things that need tinkering and adjusting and fiddling. I guess that's why I like the old cars, sort of like I prefer old steam engines over electric or diesel trains, and old piston engine planes as opposed to turbines, and assembler over Java... well, you get the picture.

seeyuzz
river

Oh lah-de-dah.
I like coherant focused radiation three-stage fusion bombs.

[river]

Hi,

..... and no one likes a smart arse!

myuk nyuk nyuk

seeyuzz
river

[mrshin]

Port injection isn't exactly new material anyway - remember, it was optional on both VK Commodore and XE Falcon, neither of which were exactly advanced at their time, and their time passed well over 20 years ago. Stratified charge direct injection has many advantages in control, emissions and economy over port fuel injection, but nobody was talking about adding that to a 2T! All I guess I'm getting at is that EFI can still actually be quite old school

15 years ago an XY GTHO, Torana XU1 or a Charger could be considered 'old school muscle cars' - what does this make them now? Also remember that the people that had wet dreams about these cars when new are now all sporting a notable cookie duster, large gut and statistically at risk of heart disease.

[oldcorollas]

15 years ago an XY GTHO, Torana XU1 or a Charger could be considered 'old school muscle cars' - what does this make them now? Also remember that the people that had wet dreams about these cars when new are now all sporting a notable cookie duster, large gut and statistically at risk of heart disease.

and paying half a million bickies for one that hasn't been creamed on by all the other old fat businessmen

[sam-131]

the cost of the motec/injectors,manifolds,wiring,tuning and so on is crazy when you compare it to carbs cosidering you could have a full house 45 dcoe set up fo around the 1k to 2.5k set up,rebuilt,tuned and blinged up

consider it this way carbs buy a holley/carter pump some fuel line and the manfold/carbs bolt it all up set the fuel pressure fiddle around with the jets and your done you might not have cold start or automatic priming or automatic shoe buffing but it does it's job bloddy well good enough and nothing beats the sound of a nicely set carb system nor the drive of one

2.5k would bearly pay for the motec let lone the other shanigans plus any half decent mind can tune a carb all thats needed is a flat head screw driver and a brain

that said for turbo setups or anything looking for every last drop of power nothing beats efi

[TheToyman75]

Yeah sorry, 0.01 lambda.
And no, you can't get a carby that good. Change the air pressure, air temp, water temp, etc, and they'll be off again.
This is why people still don't understand the difference thing - They say, and they're right, that a carby engine will make as much power as a EFI engine. Of course they will, but they will still never have as good a driveability under all real-world conditions.
A real example - A guy I know builds good Formula Atlantic engines. When I talked to him in 1998 he told me that the best power he got from Webers was 238hp, and the best on EFI was 242hp. That's close to dyno error, it's not a lot of difference.
But he said that he liked the EFI because he got 20hp MORE at 6,000rpm than with the carbies. You just can't get a carby to follow the bumps and dips in fuel flow than a twin-cam multi-valve engine has.

Bill,

I don't actually remember the last time I agreed with you but when your right your right. For a pure performace perspective Top End EFI (Autronic or Motec) with Inividual throttle bodies and the right support and tune is the cream of cream. For some people tho like River and Fonzy (And me depending on the car in question) The sight and sound and the nostalga of it can be more important. Its a persoanl choice depending on what you really want from the car.


Justin K,

200rwhp is possible form a 2/3TG hybrid, Sean Maloney Builds a cranky T series Race engine as does Graham Wilkins. It won't be what most people class as Streetable and it will be a pig to drive in any sort of Traffic. By the time you get to your power curve of around 6K plus your grandmothers Nikki 750 will be at the next set of lights wonder what was wrong with the noisey shitbox she passed. For a street car Big HP doesn't always = a fast car. Race cars don't need to run well in traffic or pull off from the lights on a steep hill behind a school bus with a hat wearing Volvo driver behind them.

By all means Go EFI Quad throttle bodies and the 3T crank, The extra cubes will do wonders for your torque and mid range. If you do decide for massive cams and hogged out ports EFI is not going to fix your low air speed, low RPM lack of performace. It may improve it compared to carbies but you can't tune out mechanical inefficiency.

[oldcorollas]

in other words...

choose your rpm range.
then tune every component to work well within that rev range.

if you want a cranky race motor with nothing below 5000rpm.. fine.. if you want something fast on the street between 3000 and 6000 fine..

but choose what you want first and optimise everything else.
althought you might have "all the right bits" now, if they aren't working well together, all you have is a collection of pretty parts

oh, and EFI does not have to be expensive.. dagnabbit.... under 1K for full system is easy to do. (fuel and ECU)

[Billzilla]

Just remember something today that should be a pretty good example of how you can't 'feel' mixtures, but in reality they can make a lot of difference.
Last November we got the racing car tuned with the new flat-slide Mikuni's. We decided to try those as we have tried for years to get rid of the mid-range rich spot that the Webers have, but could not cure.
Turned out that the Mikuni's were even worse, and we had no time to work on the problem. They ran far too rich below 5,000rpm, then the engine would suddenly light up big-time and spin the wheels in 4th gear on the dyno.
Below about 5,000rpm, the mixtures were richer than about 9:1. Between ~5,000rpm and the 8,000rpm limit though, the mixture varied from about 10:1 to 15:1.
On the track I couldn't feel anything odd at all. But we know if we can get the mixtures right there's more power in it, and we will be spending time on the dyno to do just that.
Here's the vid of the car at Oran Park, with the mixture varying between about 9:1 and 15:1 ...
http://www.youtube.com/watch?v=78JzQAs4CSw

At the lower revs you can jsut hear the engine spluttering as it tries to spit the fuel out.


Here's the car with the Webers, and again you can hear it sputtering from running rich in the lower revs ->
http://www.youtube.com/watch?v=WKu5-c6708M

[JUSTIN K]

Wow ! this thread got out of control quick - just wanted to know how far you could go with the 2tg. I enjoy the sound fo carbs as much as anyone but there really is no arguement over what is best. As far as what's fastest on the street - that's up to the driver if you have no issue with droppong the clutch at 5000 rpm - no problem. You can gain the same results but driving appropriatly for the tune as you can from changing it. Is it sensable - no!
Do we drive fast cars because it's smart - no. I love an engine that's engineered to within an inch of it's life for thoughs rare moments when nothing else will do. I have had TVR's big boost Seirra's and a sucession of Grp A rally cars as road cars and most where pigs on the road but every now and then when the moment arises.... I've rallied both here and abroad and should know better but stock road cars bore the piss out of me.
I bought my rolla as a in between car while i was back studying but I just can't part with it and that being the case - time to get silly. I really appreciate everyones input and can't believe the passion for cars demonstated on this site. Thanks guys. buy the way - i've heard Mr Malony has retired but does anyone have the contact details for the other chap mentioned?

[Turdinator]

Wow ! this thread got out of control quick - just wanted to know how far you could go with the 2tg. I enjoy the sound fo carbs as much as anyone but there really is no arguement over what is best. As far as what's fastest on the street - that's up to the driver if you have no issue with droppong the clutch at 5000 rpm - no problem. You can gain the same results but driving appropriatly for the tune as you can from changing it. Is it sensable - no!
Do we drive fast cars because it's smart - no. I love an engine that's engineered to within an inch of it's life for thoughs rare moments when nothing else will do. I have had TVR's big boost Seirra's and a sucession of Grp A rally cars as road cars and most where pigs on the road but every now and then when the moment arises.... I've rallied both here and abroad and should know better but stock road cars bore the piss out of me.
I bought my rolla as a in between car while i was back studying but I just can't part with it and that being the case - time to get silly. I really appreciate everyones input and can't believe the passion for cars demonstated on this site. Thanks guys. buy the way - i've heard Mr Malony has retired but does anyone have the contact details for the other chap mentioned?

Talk to Sheepers as when he was in melbourne recently he spoke of wanting to catch up with Sean. He would most likely be able to get you in contact with him if anyone on here can.

And i agree completely about modified cars. Its not smart or logical to drive one but i couldn't go back to a stocker. There's no challenge in driving them...

River i do believe that old school cars, especially performance ones, should be on carbs. You just can't beet the sound and feel. But i would never claim they are better than EFI.