Hello,

I request you all to give me some advice.

Am trust me am not one of those OP who will ask advice and then do what they fancy. Am here to listen to the best and hey HT Turbo nerds always best in the town.

Well this is the situation:

My setup is:

F23 block - stroke 97mm
H22 head - port matched - decent port work. supertech dual springs and crower cams - hope to get pro 1's later as they seem to work with turbo just fine.
Bore - 86.5mm
Displacement 2256cc
Comp 9.88:1
Turbo Journal bearing GT3782 - Comp inducer dia - 59.10 exducer dia 82
Compressor trim 54 - A/R 0.54
Turbine DIa - 72.50 - Trim 84 - A/R 1.12 - T3 divided

I want to use this for my build. I got the turbo on a deal and took it, not realizing how big these things are. Now I have cold feet and am scared to get this wrong. And selling or trading the turbo is not a choice for me. I want to keep it and live my choices.

I have been trying to find online a spool time calculator, or turbo lag calculation or something of that sort. I could not dont even know if they exist. But i really want to try to guess the closest estimate where i can expect boost on my setup. I dont mind lag but i dont want to see boost at 7000 rpm or something.

My aim is or what would be acceptable to me:

Boost 14-18 psi
RPM - 5000 rpm hope to see 14 psi there.
Power goal: 450-550 hp (maybe more when i go water meth later on)

Choices:

1. GO twin scroll top mount, twin 38mm WG - long runners with my T3 divided A/R 1.12 housing

2. Change housing go A/R 0.89 T3 open and short runner manifold single wastegate.

Which setup you think will get me to my goal of seeing 14 psi at 5000 rpm?

Some ladies for your patience to read my post.




Hope some of you decide to help me choose.

Regards

 

You've got the displacement to make that turbo work, have a divided manifold made and enjoy quick response and a fat, broad torque curve

 

Thanks sir.

I know i troubled you with this before.

Its just on the island where i live, people dont use turbo which are similar to what i got and everyone is just so busy scaring me that it wont work.

last night i had a chap telling me how his 1.3 tiny turbo toyota will leave me behind... I dont see the logic cause even non turbo my low comp lunches his little metal case.... But it does make a person question stuff.

Thanks alot sir.

Regards

 

Any other opinions?

 

Notice I struck out the last part. With that N456 72mm Exhaust wheel, and that Turbine housing, I entirely disagree, as we've used that before on 2.2 litre engines with even more cylinder head efficiency that what you have. DO NOT expect "quick spool" in the slightest, though you will reach the power level that you want.

Although you are right, the Tiny Toyota turbo WILL outperform you for the first 1000 yards with this turbo. I won't advise you to change anything you don't want to, however, the characteristics that you're looking for out of this turbo will likely happen, but not at the boost level and RPM you're looking at.

Unlike Wantboost, I'm not as optimistic, having dealt with this turbo before. The numbers may look right, but.... nah, in actuality not as good as you think.

 

Thank you shodan, your input is vital.

So in my two possible options what would in your opinion will bring me closer to my hopes?

The smaller turbine housing?

Sir, the whole idea to make this thread is that i want to change what i can before its too late.

I cant change the turbo, but will take advice on change whatever parts in it or around it so i at least come closer to what i want.

Regards

 

As in first 900 meters?

 

As in, the point isn't the exact distance. The point is, the smaller turbocharged OEM "tiny" car will accelerate faster more quickly than you, be it in Metric or Standard measurement.

As for changing that housing, turbine wheel measurements need to be made first because it may be that something has to be machined to fit. So you're looking at serious cost for that just to say you have "no other choice" but to keep this turbo.

 

Hello,

I spoke to a garratt supplier turns out that GT3788r and this GT3782 have the same turbine wheel and same turbine housing.

I said i have to keep the turbo, as

1 locally i dont have anyone who would want to buy or trade this turbo from me

and 2 internationally just the shipping cost from my country to the USA if i find a buyer will be worth more than the cost of the turbo.

I know i have made a mistake in my choice of turbo - now i really have two options either i can sit and cry about it or just get on with make the changes i can and live my mistakes.

DO you have a better solution sir?

Regards

 

I never said you couldn't use it. I was simply saying that don't expect what you're asking for from it.... even with the smaller T4 housing.
What you have is very popular with the Cummins 6.7 Turbo diesel crowd, and Ford Powerstroke 6.0 Litre crowd. so yes, it can be sold very well in the U.S. and other countries that use diesel engines.

Here's the problem you have my friend. You can get the entire GT3788R turbocharger cartridge (Compressor cover, compressor wheel, turbine wheel, and center section = Cartridge). You can even get the Stage kits to fit the Cummins and Ford, as well as the WHOLE turbo with smaller turbine housing. You cannot get the turbine housing itself, (at least new, anyway. Ask me how I know this. )

The only other way I can see this to even possibly work is to ask your local dealer about part number 773627-0001 which is the GT37R's T3 .89A/R Turbine housing. I'm not sure however, if the turbine wheel diameter would still fit the same there are about 4 variations of the GT37R, in which you already know the first two, the GT3782 and GT3788R. Your local dealer will need to measure.


Some of us here have several turbos on the shelf... We'll get the other one that fits the correct need, then sell the old one at another time. (like you said, sometimes as a loss, but not a complete loss) That's how we learn from our mistakes.

So yes, the solution is there, but its pretty grim considering that the GT3782 has been discontinued as well as many of the GT3788R family in the way of new parts.

Next time, don't be so frustrated at other people giving suggestions....you never know what people come up with.

Good luck.

 

Sir,

Thank you for your reply.

I will consider all your words very carefully.

I checked the website, both GT3782 and GT3788R have the same turbine wheel which is 72.5mm. I do not have a garratt dealer local or i would contact him.

I think i will definately replace the turbine housing for the part number you gave.

After that would you suggest using a small runner turbo manifold so it can help it spool just a tiny bit faster?

What kind of rpm can i hope to see the 14 psi am dreaming off?

Thank you for your time, I hope you will give me some more.

Kind Regards

 

Please see my comments in blue

 

Sir,

I will go A/R 0.89 housing T3. I still have not bought my manifold, i will go for a short one bottom mount.

I hope that would solve my problem?

Regards

 

It will help. (if you would tell me what you consider to be a "short one" manifold).. remember as I said, its the compressor/turbine wheel combination on your engine that's the major issue.

 

Sir,

you are absolutely right, i read the compressor map and thuogh yeah this is great, but i dint consider the turbine at all. stupid me.

For the manifold i was hoping like a mini ram, it is the shortest runners on a tubular manifold. Also i wish to ask how big a Wastegate i should use?

With the small 0.89 a/r t3 housing on the turbo.

Regards

 

Well, you're bleeding off a lot of boost pressure with such a large turbine wheel, I'm a bit more inclined to use either a TiAL 44mm (standard or MV-R) or the Turbosmart 45mm. I'd use a .9bar (12-13psi) in either case.

The smaller one could work, but you're in such middle ground with this turbo that If you were to use a 38mm TiAL (standard or MV-S) or a Turbosmart 40mm, with a spring of about 12psi-13psi (.9bar) you'd be in better shape than a small spring.

 

That turbo is simply too big and will likely have the worst possible characteristics like TheShodan is telling you. I hear you saying that that you can't get rid of it, but IMO if you can't cut your losses and get something more suitable, don't do it at all.

 

Hey sir's,

Thanks for the opinion.

From what i understand this is what is going to happen with both my turbine options:

Turbo will see 14 psi around 4000-4800
Then it will start bleeding boost around 6500

But i will never be boosting 30 psi, the compression of my engine is 9.88:1 and with the crap 92 ron (at best) fuel we get here i wont be able to up the boost more than a hopefull effective comp of 14 or so. Which would be max boost 8-14 psi.

In the future I may rebuild my old engine with a comp of 8.00:1 with that i hope to run around 20 psi of boost, i should see the same numbers.

Even more my car will always be on street tires, we dont get drag radials locally and are not allowed for now to use them in events anyway. Its always street radials. SO now putting down the 450+ hp on street tires is going to be a whole new issue. If am not wrong.

If the turbo is able to provide for that (14-20 psi with lag as in from 4500-5000 rpm upwards), why should i worry about it being too big. I want turbo lag i dont want to have any boost down bottom.

Am i getting this right ? Or losing my mind?

Regards

 

I guess it all depends on your power band you're setting it up for.

I'm also running an 86.5x97mm F23 block with 10:1 pistons but with a much smaller T3/T4 57 trim turbo. I'm also using a stock F23 top end, so my power band is is limited to below 7,000rpm. That' that's just fine for me because it makes endless torque below the curve, and power is smooth and strong right off idle.

The H22 head is going to let you carry torque higher, which means you'll make your 450hp goal at higher rpm. With a turbo that large making the boost you need to hit your goal above 5,000rpm, I'd speculate that your powerband will be very peaky and brief.

If you're after a well mannered car that doesn't rip the tires loose right as it's time to shift gears, then you absolutely don't want to run that turbo.

 

1.12 hotside is going to spool so damn slow dude.

even with a really really nice Twin scroll manifold, we are talking 5k+ just to start spooling.

I had a 1.00 AR hotside on a 2.0 and saw spools above 5k rpm.
I didn't see 20+psi on that turbo until after 6k RPM. and that hotside was SMALLER than yours.

get a smaller hotside or you are going to hate it.

1.12 doesn't sound like alot, but it's ******* huge.

you will have to shift as soon as you hit full boost I promise.

 

OK guys,

As i can see, most of your think this turbo is a loss.

And wel i have already bought it and everything - i think this course of action makes best sense. CHime in say what u think???

Course of action:
- Twin scroll setup - twin 38mm WG's with 0.9 bar springs.
- run the big 1.12 a/r turbo as it is with the twin scroll
- see how it works out, when it spools etc.
- if am not happy - at a later stage i switch turbo go for a smaller turbo with twin scroll.

They way i see it, if this turbo is going to sleep in the wall like the shodan said - all of us have a few reminding us of mistakes - it might as well do some working before i retire it on the wall.

And a twin scroll setup will work on a smaller turbo also, so i just have to slap a different turbo when am fed up with my big slow spooling a/r.

What do u guys say?

 

I say theories are completely off on how these divided housings will work. I guess have to give a bi-annual reminder of the differences between a twin-scroll vs. a divided housing.

As well as how you think you WANT lag in lower rpm range.. But you'll figure it out.
Stick to the original plan with the smaller housing. 2 wastegates is completely asinine.

 

OK OK Big boss,

dont blow a top captain.

So manifold chioce - Mini ram un equal runner or Ram horn with equal runners?

Regards

PS: God i am bugging you guys, sorry.

 

Where I come from, a custom equal length manifold and two wastegates can easily be twice the cost of what it would take to replace that turbo of yours.

I think you're being far too optimistic of the improvement in spool you'll get by going with a twin scroll setup, and the car is going to behave exactly how you DON'T want it to.

 

AFA - sir

I have read your build so many times, big fan. Took all my bearing ideas and building the F23 block idea from you.

Na will follow you big boys, go for the smaller housing with simple single gate manifold see what happens.

Regards