Converting 1GGTE from Twin Turbo to Single Turbo

[1GSupramanGTE]

Hey guys,
So I own a 1986.5 GA70 Supra with a 1gen 1GGTE powering this heavy body, Well The engine is currently pushing about 261hp since my last dyno run just after doing these modifications:

Apexi S-AFC Neo
600x300 Intercooler
3" Cat back
and set boost to 12psi on stock CT12 twins.

The car runs well, nice and strong since I got her tuned, she was over fuelling like there was no tomorrow, without the S-AFC tuned she ran horrible, Anyhow so I have a Hitachi HT-18-II Single turbo direct bolt onto the 1G manifold sitting at home looking all pretty, cute and useless, with this Turbo I have a 3inch dump pipe sitting next to it all snuggled up knowing there is no fumes running through it, so it has come to the stage where these two things are about to receive some activity.

Now I've heard that you can push the HT-18-II to around 15 psi or so? Im not sure but this is what I've Heard, anyway the reason why I am posting this thread is because I want to know what are you're thoughts on this conversion, So please post them.

Also what do you guys reckon I will push with this turbo and Dump pipe on?

Thanks Guys!

[rustalot]

Hi I'm running a stock gen1 1G with the water cooler and stock ecu, when you say tuned are you running a stock ecu injectors etc. besides
playing with the timing is it worth getting a dyno tune for improvement for myself can you play with the air flow meter i haven't got a boost controller yet thats still to come..
any info would be great thanks

[1GSupramanGTE]

Hi I'm running a stock gen1 1G with the water cooler and stock ecu, when you say tuned are you running a stock ecu injectors etc. besides
playing with the timing is it worth getting a dyno tune for improvement for myself can you play with the air flow meter i haven't got a boost controller yet thats still to come..
any info would be great thanks

One thing that i will advise when it comes to the gen1 ECU is, when ever you play with the airflow (aftermarket Intercooler, Upping boost, ETC..) you will need to either get a stand alone ECU or some type of Air Flow Management as the gen1 ECU seems to overfuel the engine upon detecting anymore airflow than the stock amount, I am currently using the Apexi SAFC, works very well and was a cheapish fix, here is an exmaple of what happened to me.

On my first dyno 100% stock engine, stock boost, stock everything, my gen1 1g ran 198.9rwhp, so after that i installed 3inch catback exhaust, 600x300 intercooler and upped boost from stock to 12 psi, i then ran the dyno again, and only ran 191.6rwhp.

Short answer: Overfueling
Long Answer: The tuner told me that the ECU was overfueling the engine due to airflow modifications I did. He then offered me a redwolf ecu, quoted 3k purchase, i told him im not interested as i knew what to do streight out - Apexi SAFC!

Ever since the AFC was tuned.. my cars power and response is just amazing.

All internals are still stock on the engine.

[rustalot]

Thanks for the info very helpfull i'll be looking to purchase a neo and do some necesary plumbing mods.If any one can recomend in sydney a dyno tuner experienced using the apexi i'm all ears..thanks

[1GSupramanGTE]

Thanks for the info very helpfull i'll be looking to purchase a neo and do some necesary plumbing mods.If any one can recomend in sydney a dyno tuner experienced using the apexi i'm all ears..thanks

No worries, Hope it all goes well, It is nice to see that some people are willing to give the 1g a chance.

[Magnm76]

Interesting thread mate I have a gen3 1G GTE in my ra23 running stock ct12 @ 12psi. I had it dynod , it made 204rwhp. Do u think I have the same over fuelling issue ? It seems to run rich. It runs a wolf v500 ecu tho . No one in wa will touch it.

[1GSupramanGTE]

@magnm76

My car is currently running 201.1rwhp after tuned, so i would say you have a pretty good tune already, the stand alone ECU i was offered was a Red Wolf ECU and they would only touch the Red Wolf ECU's, But i go the Piggy Back instead, besides Stand alone ECU's are much better than Piggy backs.

with 12 psi from stock turbos on a 1G i would say 204rwhp is pretty good

Will be converting to the Single in the next 2 months, ill keep you posted

[Magnm76]

Yeah please do mate. Are you getting the manifold custom made? Are you goin for forged pistons ect as well? i have been tossing up modding the 1g or save the coin for a 1j

[1GSupramanGTE]

The turbo is a direct bolt on for this manifold, it was previously on a 1G but it got stickerd, so the turbo was only in use for a few weeks, maybe later on ill consider a Y manifold, i just want to see how this turbo will go on this engine. Forged pistons? maybe a little later as I am currently focusing on a turbo upgrade.