18R/RG performance

[kingmick]

well you would the ports and chamber spot on with 12.5-1 in a sprintcar! sprint cars have diffrent loading from cicuit and drag racing! a well built sprint motor makes a good circuit motor but there are diffrences.
points are fine at 7500rpm if you have the spark energy from something like a 6a msd!

[o_man_ra23]

well you would the ports and chamber spot on with 12.5-1 in a sprintcar!

me no understand you english... did you mean you would want the ports and chamber to be spot on??

Also, having not had much experience with sprintcars, my understanding is that their greatest limitation is heat, due to the fact that you dont want an exposed radiator collecting other driver's debris. fuel mixture would make more of a difference in a higher compression motor with regards to chamber temperature wouldnt it?? also alcohol cooling could have power gains with that kind of compression without resorting to a full methanol system.

If im wrong about that, please feel free to shoot me down in flames.

Cheers, Owen

[kingmick]

will not shot you down at all! if you dont know you dont know. yes i ment the ports and chamber had to be spot on{ im hopeless typing} and sprint cars have diffrent loading from circuit,drag and street. much more noticable in smaller lower torque engines. heating can be a problem if the system is not setup properly but if it is the lower speens and the protection you have to give the radiator dosnt really matter. yes meth has a good cooling effect in the chamber but the octane is what is needed. i dont know how you would run 12.5-1 reliabley in a non crossflow engine on pulp when we are on 12.5-1 on big dollar crossflow race engines! it would be ok for drag racing as you are only going a few hundred revolutions but in circuit or sprint you would be lucky to get away with it.

[kingmick]

lol god sorry! im trying to help the kids paint and answer! i speak goodly english bestly!

[OSJ]

The 8R-B with factory 10:1 high comp pistons and twin S.U type carbs out of the 1969 RT72 1900SL made 124HP @ 6000RPM,so similar mods to the 18R,some head work and a cam should get close to 130-140 range.Boy those early MK2's were great cars!

[The Witzl]

i would have thought that for the cost of building such an 18R (OHC) with the whole methanol setup and custom camshaft etc etc... you could have just gone and bought an 18RG complete!

There's two on ebay at the moment... one really clean looking one for $1100 buy-it-now... and there's even one in a 4wd hilux!!

I've just recently rebuilt my 18R-G with 18R-GEU fuel injection, 0.5mm o/s 9.7:1 comp pistons (oem), decked block + head, balanced/machined/checked/inspected everything.... and i would put the power easily over the 150hp mark. I ran the previous engine (EFI, 8.7:1 pistons) on the dyno and scored 72rwkW on just 3 cylinders, thanks to a bend no.4 exhaust valve......
.... this just goes to show how strong the 18R-G really is.

In your situation, if you are going to BUILD an engine, then i would start with an 18R-G. If you need one in pieces that you can go ahead and rebuild to your specs - then I am the man to speak to, I have FIVE 18R-Gs at home!!
... and rebuilding one to stock spec with 9.7:1 pistons and re-using a few "good enough" parts (eg. timing chain slippers/dampeners etc) should cost around $1000-2000 depending on what you go for

oh... and despite what people say - the Solex Mikuni carbies are GUN. Why did TRD recommend and use them religiously??

[The Witzl]

lol god sorry! im trying to help the kids paint and answer! i speak goodly english bestly!

[Screamn_Sleeka]

I've just recently rebuilt my 18R-G with 18R-GEU fuel injection, 0.5mm o/s 9.7:1 comp pistons (oem), decked block + head, balanced/machined/checked/inspected everything.... and i would put the power easily over the 150hp mark. I ran the previous engine (EFI, 8.7:1 pistons) on the dyno and scored 72rwkW on just 3 cylinders, thanks to a bend no.4 exhaust valve......
.... this just goes to show how strong the 18R-G really is.

And u have no idea how much me, and a lot of other ppl, want to know how much it is pushing to make that easy 15.8

[o_man_ra23]

i dont know how you would run 12.5-1 reliabley in a non crossflow engine on pulp

Neither do i... that is why i suggested doing it to an 18RG, and tried detering the use of an 18R or 18RC non crossflow(OHC)

Twincam or bust i say, the 18RG was designed for high compression, high rpm race use, and should be the weapon of choice for anyone building a race R series motor.

Cheers, Owen

[kingmick]

hahahaha thats not even close! Try fresh painted walls that now look like prohart has gone to town on them because i dashed outside to measure up the new intake on a car! lmao
god it took me two hours to scrub the walls!

[kingmick]

Neither do i... that is why i suggested doing it to an 18RG, and tried detering the use of an 18R or 18RC non crossflow(OHC)

Twincam or bust i say, the 18RG was designed for high compression, high rpm race use, and should be the weapon of choice for anyone building a race R series motor.

Cheers, Owen

sorry im half reading things while i try and get work and other things done!

[o_man_ra23]

As you do, dont you just love slaving away??

[kingmick]

lol think a year off from the stress of racing was replaced by the stress of looking after 4 kids under 7 and trying to do car work!lmao i tell you what i look at mums in a diffrent light after doing it for awhile! god i would have killed me as a kid!hahahahaha

[dale30]

i would have thought that for the cost of building such an 18R (OHC) with the whole methanol setup and custom camshaft etc etc... you could have just gone and bought an 18RG complete!

There's two on ebay at the moment... one really clean looking one for $1100 buy-it-now... and there's even one in a 4wd hilux!!

I've just recently rebuilt my 18R-G with 18R-GEU fuel injection, 0.5mm o/s 9.7:1 comp pistons (oem), decked block + head, balanced/machined/checked/inspected everything.... and i would put the power easily over the 150hp mark. I ran the previous engine (EFI, 8.7:1 pistons) on the dyno and scored 72rwkW on just 3 cylinders, thanks to a bend no.4 exhaust valve......
.... this just goes to show how strong the 18R-G really is.

In your situation, if you are going to BUILD an engine, then i would start with an 18R-G. If you need one in pieces that you can go ahead and rebuild to your specs - then I am the man to speak to, I have FIVE 18R-Gs at home!!
... and rebuilding one to stock spec with 9.7:1 pistons and re-using a few "good enough" parts (eg. timing chain slippers/dampeners etc) should cost around $1000-2000 depending on what you go for

oh... and despite what people say - the Solex Mikuni carbies are GUN. Why did TRD recommend and use them religiously??

Well i feel like a leper only having one camshaft,But thats all i got.
I thank everyone for all your suggestions

I allready have a fresh race prepped R and cant afford to start again.
It has performed well in its class this season but is moving up to a bigger class.
I ran it in this class last meeting and ran 6th out of 25 cars, most of which are 300+hp falcons and commodores.Corona is small and nimble amongst these cars and naturally handles better and It gets every ounce of hp down to the track.
The stock cam wont pull past 6600 so we just hold it flat.
A new cam will fix that and a big head shave for comp.
Not quite sure what i was asking for, Maybe some magic tricks.( eg: this head has smaller.chambers or flows better etc: )
Dont blame anyone for not experimenting with these things,Just thought i would ask.

Do have another question though.
what is a good strong diff thats the right width for the XT130.Dont mind changing the mounts so leaf or coil is good. If it had about 3.7 oe 4.4 ratios available that would be better.

[o_man_ra23]

try an F series or a G series. F series is lighter, G is stronger. Also G you can get ratios anywhere between about 2.7 and 5.2 or so. RN40 hilux G series diff should be the right width. Brett_Celicacoupe seems to be the diff expert, so you should bug him.

The only head that will fit on the 18R which has good flows and is worth bothering with is the 18RG head. All else is POOOOOOOOOOO and putting an 18RG head on an 18R block is harder than race preppin an 18RG.

Cheers, Owen