2tg

[jew086]

can you get a 2tg out to 2ltrs
also want to use quad throttle bodies
haltech
extractors mandrel bent exhaust
ported head and lots of work ie springs
big cam to go 8000+ rpm

any one got any ideas on power atw from this combo?

[styler]

1.
1940cc is the "2 Litre" setup using the 3t crank at 78mm and
3t 89mm off the shelf pistons.

you can go:

90mm custom pistons apparently if you resleeve or grout fill but its very expensive,
some 3tc drag racers in puerto rico do this. for NA or turbo applications.

89mm off the shelf is only recommended for NA applications, results in thin walls.

88mm custom for NA or turbo applications.

87mm is the next off the shelf avaliable size for NA or turbo applications.

however if you have many 2tg blocks and can ultrasonically test the bores
then you might find one that is suitable for a safe bigger overbore than
recommended or you can offset bore the block if its suitable.

however, its not just breaking through the walls that you need to worry about,
its the bore distorting from a thin wall that can also be a problem with loss of
compression, losing more power than the mm extra overbore made.

you need to use the 3t crank and pistons as a combination, you cant use
2tg pistons. this is due to the stroker setup, 2tg pistons on a 3t crank are too
high and would smash up into the head.

also concerning 3t pistons, their compression ratio stated is for a 3t motor
which has a bigger combustion chamber volume 63cc i believe, whereas
a 2tg motor once the head is skimmed flat has only about 52cc. this makes
a big difference when doing compression ratios and check what fuel octanes
are avalaible. get your head chambers cc'd with a burette before buying pistons.

3t turbo pistons are way lower compression but are too low for big cams.
big cams need big static compression reading which with a big cam will
result in decent dynamic compression ratio.

the 3t pistons have to be flycut to clear the valves, aftermarket 3t psitons have
an oversize valve reliefs and dont need to be machined as far as i know,
always check first though.

2.
quad throttle bodies will be ok, it would be a custom set or use weber dcoe carbs as
the throttle bodies with injectors and managment.

3.
aftermarket management is very good provided its tuned properly.
you can go semi diy or full retail setup. remember tuning costs a lot too.

4.
extractors and exhaust fine, many brands of extractors. dont go too big on
the exhaust, you can use some calculations to design an exhaust system for you.
go mild steel pressed, stainless steel mandrel is expensive for what you get.

5.
a set of cams that go past 8000rpm?, id say a set of 320 deg cams
should go from 5000 to 8000+ with a very rough idle and poor drivability but
it does 8000rpm+. not for a daily street car, it would be a pig to drive.

6.
power? with something from the above gear, about 120kw or 160hp at the fly.
2tgs arent dyno queens, they are in lightweight cars with good handling,
and as such, its not all about the peak power, but how you get there that counts.

[jew086]

forgot to mention that this set up will be for a rally car if i like what i hear from the engines. so dont care bout how rough it will idle.

What is the better engine the early 2tg or the later one?

[jeffro ra28]

You dont need very big cams to have a 2tg perform well at 8000rpm
heck i had 252 deg cams on my stroked 2tg and revved it to 8500 rpm with ease.

EFI hardware is the place for your aftermarket throttles. http://www.efihardware.com/efi_throttle.html

[Roscos]

Go and get a 1750cc pistons and a head gasket to match and throw a 3T crank and rods into the 2TG block, that will give you approx 2 litres. You can bore a 2TG out to 2 litres but it won't last long and its not recomended.


Roscos

[styler]

Go and get a 1750cc pistons and a head gasket to match and throw a 3T crank and rods into the 2TG block, that will give you approx 2 litres. You can bore a 2TG out to 2 litres but it won't last long and its not recomended.
Roscos

indeed the 2 litre capacity as in 2000cc is very tempermental if
it can be done on a particular suitable block to start off with.
people seem to say "2 litre" as in 1940cc capacity.

I think you might be a bit mixed up on the pistons, the 1750cc
pistons are used for the "short stroke high rev" build of a 2tg
and are 2tg pistons. they have to be used with a the 70mm stroke
2tg crank.

the "hybrid" / "3tg" / "2tg/3t" / "2tg stroker" build uses a 78mm stroker crank from a 3t with 3t pistons.

you cant use 2tg pistons with a 3t crank. the reason is because
its a stroker crank, it comes up higher and a normal 2tg piston would
be lifted up higher, ie smash up into the head. the 3t pistons have a
higher pin height so they can be lifted up the extra amount but are connected to the rod at a lower height.

[Rodger]

Joe,

I'll add my comments and hence subscribe.

Heading in the right direction except for rally it is all about good mid range torque. A peeky motor will not be managble on the dirt.

Capacity by adding stroke and bore adds torque. Compression also aids torque. So for the motor I reccomend (reiterating some of the above).

89mm bore pistons to suit 3T with modified flycuts to suit the different 'G' valve angles. I think Wisco make the set you need, or ask Specialise Piston Services in Melbourne. Aim for 11 or 12:1 compression ratio about the limits of PULP.

Of course the 3T crank.

The 2T-G OEM Manifold can hold a set of "DOCE" style EFI throttle bodies. Also check Meridian Motorsport.

Light flywheel. This will give you a lot of benifits and will allow the engine to respond (speed up and slow down) much quicker.

Talk to Dean Tighe at Tighe Cams for suitable rally spec cams. You are looking for torque and hence power between 3600 rpm and 7500 rpm.

Look for head mods that make for faster air speed and make the combined intact tract length as long as practical. Use OEM stuff and the longest Ram tubes that clear to the Strut towers. Assuming you go tandom brake master cylinders and no booster.

[Hurricane]

im building a 2ltr 3t right now its costing me $640 to sleave it, so not really that much, and im runing 89mm 12 to 1 arias pistions, losts of people told me that i can get away with just boring but i would rather just sleave it as its not that much more.

cheers, dan

[jew086]

by 2ltr i mean 1940cc set up.

[pro_k]

Rodger has made some valid points.

Speak to Wade Cams about a suitable grind...around 280 deg is what you are looking for.

Its all about Torque if you want to rally.

Dont use a lightened flywheel not good if you want to make use of your Torque.

You are looking at around 7000RPM, dont need anymore. Aim for a flat torque curve from 3000-3500rpm onwards.

Clean up head but leave as close to standard as possible - you need reliability. Start with a very good head.

Use Forged pistons if budget allows. Make SURE its Balanced very well.

Then just enjoy...if built right they are a tough motor and one of the best sounds in the forest on a cold night.

BTW - What car will this go into?

[Rodger]

There you go. Two different opinions on flywheel weights.

I suppose my argument for a lighter flywheel is simply: throttle and thus engine response. So going off throttle the engine drops and provides engine braking and then on throttle it picks up quickly. Higher speed sections where a sensitive right foot matches a sensitive engine allowing faster weight transfers on and off throttle faster change of road speed.
And I suppose less power loss from turning the flywheel. 1kg off a flywheel running at engine speeds is equivalent to a performace increase (in acceleration) of taking 15kg off the vehicle.

Found my reference: Chassis Engineering, Herb Adams, HP Books, Berkley Publishing Group, New York, 1993, Chapter 15, Rotating Inertia

Regards

Rodger

[jew086]

this will be going into a TA22 celica.

[pro_k]

Rodger - Yes true on a race car but on a rally car the engine seems to spin up too fast (if you know what I mean). Remember we are looking for a nice spread of torque rather than free revving top end power. The "3TG" by nature in not a highly strung motor. In blind events we are usually in 2nd and 3rd (mostly) and maybe 4th (close ratio box). Would be worse in a normal box. I guess it has to be felt. Ultimately depends on driver preference and style.

Jew086 - Speak to ppl who have owned rally TA22's as for set up of car. You will save lots of time and money in R&D this way. Make sure you build the engine right the first time. Then you can concentrate on other areas without fear of engine rebuilds etc.

[Rodger]

Yep good idea Pro-K, speak to people that do a lot of rallying particularly ones running in in similar cars, Escorts, Datsuns, Geminis, Galants etc.
Most of my experience is, admittedly, on the track but I also personally like the quick engine response also on the dirt, for me it gives me better car control.

Either way a 1940 cc 3T with good compression will "pull stumps" all through the mid range and as Pro-K is saying, right where you need it. Almost a "tractor engine"

Regards

Rodger