Hello!

Does anybody have a boost log for 3sgte with garrett gt28r?

PS or appx. revs for 0.7 and 1 bar boost?

Thanks in advance

Do you mean GT28R like in GT2560R, or the GT28RS(GT2860)?

I have no logs of this turbo on a 3sgte, but it has trumendous spool and air for about 310hp.

Especially the Gen 3 and the GT2860 is a great combo for fast spool is stock condition.

Lots of info on that turbo on a 3sgte on this site.

http://www.mr2oc.com

Have a look.

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ST185 CS #1845

i'm asking about gt28 because it have "big" enough compressor and low response with 2ltr engine (may be rumors). Of course stock gen3 turbocharger suits well, but i already have custom exhaust manifold with T3 flange. My object is to build something similar to boostlogic compound turbo system, cause i feel bored with high revs and torque after 5000 rpm.

The GT28 should spool early. From various compressor maps it should be hitting it's stride about 25-2600 rpm with a bar of boost available by 3000rpm. You'll need to push it quite hard to get mush over 350 bhp though

An alternative is the internally gated 28 hotside with a gt30 compressor using a large extrenal wastegate (i'e do not use the internal wastegate). This should still spool well due to the small hotside but the large WG should help alleviate choke
I hope so anyway..........

i have KKK29 already installed, it's operates with huge lag, and the idea is to make KKK compressor operate only at 13psi and let it blow through GT28 compressor (with intercooling of course) while 28's turbo will get energy directly from engine and then pass it to KKK turbo making good low response. So at the gt28’s entrance will be not very big volumetric flow but with higher density. So in this case this flow will be in good efficiency zone of compressor map of 28's, but ~twice denser. You can find in internet this type of setup (one DSM forum, 2jz engine, etc)

sheme:



what i have for today:

Space is obviously the big issue with that setup

But with your (Greddy?) manifold shifting the big turbo like that it's a bit better

I keep looking at the place where the AC pump normally lives and thinking that a little rootes style supercharger would work there

There's a few examples of twincharged setups like that about. The large turbo blows into the supercharger giving you (in theory) the best of both worlds. Boost from idle due to the supercharger and a good kick from the turbo later

There's a huge thread about it on the interweb somewhere by a guy in Australia building a twincharged sprint car. Can't find it at the moment

I think you'll get restricted by trying to get all the air of the big turbo through the small turbo's housing.

But the consept looks exiting.

Thought they use this setup in tractor pulling.

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ST185 CS #1845

This thread is a good read (along with some of the linked posts)
http://www.toymods.net/forums/showthread.php?t=9303

cameron_datto, who posts in the thread, is the guy I was thinking of

http://www.turbophile.com/feature_cars/ ... _1200.html

two_OH_five
in my opinion mechanical compressor and turbocharger setup is much more complicated by intake side, plus more stress to crankshaft. With sequental turbo setup (according to drawing) the problem only with underhood area. But for st205 we have a lot of space in front of engine.
I think it is possible to place second turbocharger to the left of existing. Problem only with second IC and i see two ways - make "doubledecker" or place second one horizontally in the front of car between engine and boby.

ST185pinjo
no restrictions if you will choose right sizes for each turbocharger. I already wrote main idea - volumetric flow is low, density high, so you just rising up pressure ratio. Goal is - you have ~30psi in intake with lets say ~25 in exhaust and also goal in multiplying of pressure ratio at all rpm range.

to the left from turbocharger a lot of space:



exhaust

The GT28 is probably overkill in that role.

Something small like a gt25 might be a better bet. It will spool even earlier and requires even less space

In fact with two turbos I'd be looking at something along the lines of a tiny GT15 sized thing and a GT3071

Plumbing is quite a headache though. The 2jz uses a load of bypasses and valves to achieve sequenial operation

i am agree with you about GT30 and GT25, but to change existing turbocharger and buy two new "ball-bearings" - additional expences and GT30 will make limitation with ~500hp, but 553 already reached.
Also i can find GT28 with T3 flange, so my expences only in GT28, one additional most biggest WG, smallsize IC (may be half from mmc evo) and pipework. Fuel system is efficient enough - 4*1000cc and two pumps.
For now i have quite different opinions about GT28 spool up, somebody tells me 1bar@4000, somebode 1bar@3500....

PS i afraid, that GT25 compressor is not big enough and will be a bit restrictive

You could consider a two in one out intercooler. It simplifies pluming quite a lot

Something like THIS



Someone like Pace, Forge or Docking engineering in the UK could create such a thing with a different split. I'm sure you've got local people who could do the same!

two_OH_five
thanks, i called this "doubledecker" sorry for my english

I don't think a small hotside on the first turbo matters too much

As long as the wastegate on that is Large then it should not restrict the exhaust gas

I have wondered if it would be possible to run a small turbo off of an external wastegate port from the main downpipe. The little turbo would run without a wastegate relying on chokeing to divert flow down through the main turbo

It's a bit of a crazy idea though, not one I'd recommend

Hi,

the idea is not so bad, but i think you have the wrong engine
lancia located the exhaust valves diagonal to put 2 small turbos against one big in his rally cars, but these engine is developed from buttom to the head for such a setup

the ex.manifold is a thermodynamic catastrophe, and you also will lose energy in the first turbo, i give this idea no chance (on a 3S-GTE)

you better use one turbo and develop them to your specs (use of titan & magnesium, etc.)

greetz

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