18rg turbo psi and power

[mscphillips]

hey guys
wha t sort of boost are you running and power are you getting out of a stock 18r bottom end with the yamaha 18rg head, ct26 turbo? efi.

[river]

Hi,

160rwkw, running 14psi with a GT25R turbo. Uses 18R-G stock bottom end, 18R-GUE head, Sard 700cc injectors and Autronics SM4 ECU. Engine built for 23psi, but 14psi is fun on the streets, very responsive and no lag - plus terribly reliable (ie not pushing the engine to its limits). I'm also using stock gaskets, but I'd change them over if I was running more boost. Running ARP head bolts also.

Engine is built to take bigger turbos just by bolt-on, as the injectors and the rest of the engine (except head gasket) is ready for more power..... but OMR isn't.

seeyuzz
river

[mscphillips]

Thanks for your reply,

thats decent power for such an old engine,

you said you bottom end is stock but build for boost?

does it have forged gear? or just the arp head studs?

is the head the std item with standard cams?

[river]

Hi,

Yes, forged internals. It's the standard head. The engine was fully rebuilt from scratch. It's not like I grabbed a second hand engine and whacked on the extra gear and hoped it didn't explode. So, in that respect, it's like a new engine. There's no reason why you shouldn't be able to pull 230-250rwkw with a really well built 18R-GTE. More power again if you go for the rebore/stroker upgrade to get it to 2.4litre capacity.

It's running stock cams. The engine was initially behind an auto, but within a few weeks the gearbox was a tad worn and slipped a lot. So, she's now hooked up to a W58. The stock cams were kept because they are good for low down power, which was a requirement for the auto box. I'm sure a set of modded cams would make a difference, but my car is for cruising and looking cool. It's doesn't do the drags or the track, so it's life is spent on the public roads where the less agressive cams (and smaller turbo) serve it's function perfectly. The car's daily street manners are superb, plus she's got that extra power for the occasional spirited run or burst of power.

seeyuzz
river

[JustenGT8]

Stock pistons don't like det and you'll crack a ring land quick smart if you suffer any. A safe tune should see 150rwkw easy on a totally stock engine.....maybe not with a CT26 though.

[mscphillips]

what turbo is best for these things?? and what injector size is good, mine has a set of toyota surv v6 injectors (small) will try courier injectors they flow quite well

[jabbatron]

I have an 18rgeu running 18psi with stock internals (20r cast pistons), it has had a fresh rebuild. I'm guesstamating its making about 180rwkw going off how fast it is. I'm using the r33 s2 skyline turbo. It has arp rod bolts and head studs. I just blew a head gasket the other day, but other than that its a sweet setup . I've just got to work out how i can prevent another hg failure. Maybe the head studs needed a re-torque after a 1000km's or something. Only crap thing is my mates sr20 pulsar running 15psi is slightly faster than me .

[river]

Hi,

I'm guesstamating its making about 180rwkw going off how fast it is.

LOL!!!! Are you some sort of human dyno-detector? Hehehehe

The stock gasket is good for around 15-16 pound, so if you are pushing more you may need to look at a better gasket.

To answer the previous posters question... turbo and injector size depend a lot on what power you want out of your engine and how you intend to use the vehicle. For zippy, no lag performance a smaller turbo is better. For more power and outright top end performance then you get a bigger turbo. Injectors size is dependant on how much power you intend to wring out of the engine. Also the tuning of the ECU is based upon the injector, so if you get smaller injectors and later on decide to upgrade the turbo and make more power than the injectors can deliver you'll need to spend a bucket load of money on a complete retune. So, put in big injectors if you are thinking or upgrading the power at a later stage as the retune is a lot cheaper and quicker.

Turbos and injectors are just one part of the build. There's also manifolds and the ECU, and the tuning. The stock EFI inlet manifold is good for 200+rwkw. You'll want a well made manifold for the turbo. Get a good ECU that can run your engine properly, and more importantly go to some place that specialises in the ECU you have and get them to tune it.

Some combinations work better than others. In my case we expected around 130-140rwkw from my set-up. The tuner was quite surprised she pulled 160rwkw, which is excellent for the smallish turbo set up (GT25R). I attribute this to the engine build and the custom turbo manifold (which is a beautiful, well designed unit), the injectors and the ECU all working perfectly together. Also the tuner knows his stuff and extracted every poofteenth of power out of the engine. It's running stock cams also, which keeps it nice and tame at lower speeds and she pulls hard even at 50kph in 4th gear. As you can see, my set up is for street use and cruising. I'm not into wrestling a powerful beast of an engine that is designed for the track or drags, when the car is used on the street 99.99% of the time - more so as it's my daily.

But.... it costs. The whole set up was not cheap, but I think its one of the best build/combinations around for an 18R-GTE and its performance and reliability are testament to this. I doubt you'd get the same power by doing a backyard job... though it would be cheaper and, if you're heavily into the mechanical side of things, very rewarding.

The guy who built my engine also built Witzy-babes 18R-GTE, and his engine was built for more performance, so all things being equal it should be a lot more powerful. Of course, if it's not then it may come down to his turbo, injector and ECU choice, plus how it was tuned.... and I will mock him I am keen to see what his engine does <hint... hurry up Witzy!!!!>

If Oman ever finishes his rebuild and it can run for more than 100metres without blowing a gasket or munting a piston then I'd like to see what power he is making also We need more 18R-GTE engines so we can compare our builds and performance etc.

seeyuzz
river

[The Witzl]

My only shortcoming will be the not-so-awesome KKR430 turbo. Basically i am only using this turbo because i have a limited budget (for the moment), so a good quality garrett or borg warner are out of the question for now.

but yes, it should make more power than yours hopefully.... but it also cost a little more to build the engine (i also have custom H-beam rods).

I guess we'll just have to wait and see what it will do.

[jabbatron]

Oh yeah, i'm using what i believe are about 500cc injectors and a megasquirt 2 ecu. The tune was done by myself with a wb02 until it was drivable, then i did some crude road tuning. After that i switched on auto tune in tuner studio. Fantastic results . I couldn't tune the car manually as accurately as the software was doing for me. Once I'm up and running again ill get it on a dyno and see what its actually putting out.

[river]

Hi,

This thread is now closed. We have an 18R-GTE thread for all turbo information and questions regarding the greatest automotive engine ever developed.

seeyuzz
river