up the power on the 18r

[Spanner]

I had plans to put an 18rg in, but they fell through money is tight so im looking at the cheapest way to gain some power.
What can be done to the 18r to increase its proformance and how much power is to be gained by doing it?

cheers

[airfireman1]

Budgets always suck especially when its a small one.
A good set of extractors, helps the engine breath better Pacemaker
Carbies and intake manifolds Can get fairly expensive but the original manifold and carby are designed for economy not power.Single or twin weber and redline manifold
Next is head and camshaft, port and polish, oversize valves and a mild reground cam.
It wont be neck snapping but you will notice a difference
Cheers

[Thomas]

The only thing I could be bothered doing to my old 18R was to whack on some extractors. A bit of a difference compared to original headers (mostly sound-wise) but mate, it still wasn't much. Stick with the RG idea.

[glytch]

Well on my 18R I have gone the cheap on it -
Extractors and 2.25" exhaust - $400+ (shelf bought extractors and mild steel exhaust)
Weber DGV downdraft (off a 2L escort) - $60-100 from wreckers
Performance filter to suit - $50 new
and I run it on 98RON and have advanced the timing to suit. (to about 12-14 degrees IIRC)

Dont know what power it is putting out, but I have a Dyno booked for the 11th.

BTW - I have also pulled off anything that may draw power that I dont need - aircon, clutch fan etc. I have replaced the fan with an electric one.

Hope this helps.

[MWP]

An 18R or 18RC?
The original 18R is quite a good engine, not too far off an 18R-G.
The 18R-C though is pretty damn crappy.

As mentioned above though, extractors and a decent carb help along with a good tune (fuel & timing).
I used a Weber 34ADM (off a ford falcon, can be had cheap at wreckers, mine was $35) carb on my 18R with good results. It did take a while to tune though.

[glytch]

I was of the impression that the 18R was pretty much exactly the same as the 18RC bar a few differences. Take off all the emissions crap and the differences come down to not alot. Still a single overhead cam, not a crossflow, etc etc. Maybe something about unleaded vs LRP only, dont quite remember.

BTW thats another thing to do. Remove all the emissions stuff (assuming you have it) might not do much, but its better than having it.

[RT104GT]

I had plans to put an 18rg in, but they fell through money is tight so im looking at the cheapest way to gain some power.
What can be done to the 18r to increase its proformance and how much power is to be gained by doing it?

cheers

G'day

Re 18R 18RC 8R 8RB its in the combustion chambers.

Some are heart shaped some are hemi, some are oval. depending on year and also size of valves vary from small 1.75 to large 2.25 inlet and 1.00 to 1.5 inch exhaust.
Cam gears changed also from three bolt to dowell especially on the 18RG.


In order 8R 8RB 8RC/8RG then 18R/18RG 18RC/18RGR 18RGU 18RE/18RGEU..

There is a 16R in there somewhere and a 16RB as well.

16RB head would be an interesting choice if you could find one.


I have been shoving 8 R series engines into Coronas since 1974.
1st was an 8RB from the 1900SL using the dual side draft Aisans.
Then I upped the bottom end to an 18R in 1976.
I fitted a single 45 mm weber and an MI cam 24/80 for rallying and the car would do 100 mph at 7000 rpm in 4th gear (no 5 speeds in those days).
Won lots of events in W Vic.
This was an 8RB high comp head on an 18R.
You wont get any better.

Balanced flywheel plus crown clutch plate pressure plate.


So for my money a cam/8RB head/weber and flyhweel, you wont know the car.

Oh and a 4.11 or 4.375 diff.

2 cents.

[glytch]

Had my car run on a Dyno today. This is still the original engine (27 years old) and could be pushing some stupid abount of Kms.

Got 67.1HP - so its pretty much back to its original spec power. You check out the graph here

[Hash_ra23]

i found this site on the 18r engine: http://ourworld.compuserve.com/homep...pho/eng18r.htm
it says that the 18rc has hardened valve seats where as the 18r didnt. 18rc also has the emmissions gear on (pcv and charcoal canister). The only other difference i cud find is that the timing is more advanced on the 18r. So i'm guessing it'd be very easy to convert an rc to an r. Anyone got the power difference between 18r and 18rc?

[thechuckster]

to convert an RC to an R you remove the emissions crap.

[MWP]

The 18R i had in my RT104 Corona (early type) was a pretty powerful engine for a single-cam.
It was much nicer to drive and quicker than the 21R im using now.
Yes, i can compare them very well since they both used the same 34ADM carb and same exst in the same car.

As the 18R's went on in revisions, they dropped the compression ratio to pass emissions.
Hence why the earlier 18R's were quite a bit more powerful than the later 18R-Cs.

BTW, the early 18R's came with charcoal cannisters too.

[Hash_ra23]

As the 18R's went on in revisions, they dropped the compression ratio to pass emissions.
Hence why the earlier 18R's were quite a bit more powerful than the later 18R-Cs.

BTW, the early 18R's came with charcoal cannisters too.

From further research i found this is true. THe 18r has a compression ratio of 8.7:1 and the 18rc has 8.5. Dont know about the 18r's having charcoal cannisters tho.

i guess its not as easy as earlier thought to convert 18rc to 18r specs.

[RT104GT]

i found this site on the 18r engine: http://ourworld.compuserve.com/homep...pho/eng18r.htm
it says that the 18rc has hardened valve seats where as the 18r didnt. 18rc also has the emmissions gear on (pcv and charcoal canister). The only other difference i cud find is that the timing is more advanced on the 18r. So i'm guessing it'd be very easy to convert an rc to an r. Anyone got the power difference between 18r and 18rc?

Correct 18R's ran on Super grade fuel in the days when there was only super and standard.
So did the high comp 8RB's and 1600S 4R's.

ULP only came into being with the 18RE (USA) and 20R 22RE AU.

The 18RC will be an emmision control engine with an air pump if I remember correctly.All the information is available in the Emission Control Yellow booklet from Toyota.

The cylinder head and an 18R and an 18RC were radically different one was heart shaped and one was racecourse/oval.

All TOYOTAS from 1974 had Charcoal canisters for the fuel vapour you can see them on the hand book photos.

TT100 16R
RT102 16R
RT102 16RB h/c
2000 SR/SL RT104 18RE

it is interesting that no JDM used an 18R only 18RE.


2T 100 PS @ 6000 rpm 13.7 kgm@3800
16R 105 PS @ 5600 15kgm@3800
16RB 110PS @ 6000 rpm 15.3kgm@4000
18RE 130PS @ 5300 rpm 17.5kgm@4000
18RG 145PS@ 6400 rpm 18@5300
18RGR 140PS@6400rpm 17.2kgm@4800

So the 18RE has more torque than the 18RG Regular engine.


Interesting PS rating from JDM book so someone has typo'd and attributed the horsepower rating of the 18RG as 145 BHP when in fact it is 145 PS they are different maybe not by much but I think the 160BHP 3TGTE has a lower ps rating 150??


Diff ratios used on 16/18r's are interesting

4.300 (Wagon) 4.111 (2000 GT) 4.100 (1600 and 1800) 3.909 (2 litre 18RE and Aussie 18R) 3.727 (2000SL)

And remember early RT104's with 18R engine were all four speed gearboxes.
They only went to 5 speed in the 18RC engined liftback vehicle in 1979 maybe??

[brett_celicacoupe]

the 1st thing you can do which is essntially free is convert the carby to a mechanical driven secondary.

remove the vacuum pot link and somehow connect the shafts.

i used a piece of wire and its worked fine for now.

power gain was very impressive.

[glytch]

Oh yeah - thats another thing. I did that on my old carby before moving to the weber.

Though mine wasn't vacuum driven. It had a little lever that pushed open the secondary when the primary was open a certain amount, I build up the lever with welds to get the secondary to open sooner.