Turbo sizes

Discuss topics related to the VH41DE, VH45DE, VK45DE, and VK56DE engines.
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LEMHEAD16
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WD what are you doing in the VH forum? I thought you were banished to KA-T long ago?


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LEMHEAD16 wrote:WD what are you doing in the VH forum? I thought you were banished to KA-T long ago?
I'm a boost addict brosef. The only reason I have a KA in my 240 is because I lacked the funds and time to do a V8 swap. This thread popped up on the active topics list and the title got my attention right away. I love discussing turbo's and projects man. Especially boosted V8's. The motors can change but the theory behind adding a turbo remains the same.

Lately I've been contemplating trading in my S14 for either a M45 (earlier model) or a Lincoln MK VIII, both would get a remote mount turbo. Being 35 with 3 kids now...the old S14 just doesn't fit my life style :frown: Something that is very comfortable to drive and can swallow huge chunks of highway at a time is more my speed these days.

WD

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hannibal
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I'm surprised that a T4 turbine works well as a single. I know the compressor can handle it, but I figured the turbine wouldn't. Brian says 4.6 guys also use T4s, so maybe using a T4 as a single isnt as restrictive as I thought.

David, youre right on about two smaller turbos giving a better powerband than that T04Z. Thats why I'm so impressed with that twin T28 build making 500hp and 600lb-ft.

Drftbld, you need two turbos capable of 300-350whp each. I know Brain would suggest a T3/T4 0.48A/R (or 0.63A/R maybe) if you put this on a KA-T, and think a pair would work well on a VH. If you have money for Garrett BB turbos, I'd say the GT3071/3076. They use the same T3 turbine (no 0.48A/R though) and the compressor maps are very similar.

Lem, anything you would have used as single on a under 450whp KA-T will be too small as a single on the VH, but should work well as twins on the VH.

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karay240
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So let me get this straight. A T28 (or whatever's eqivalent) is OK ONLY for a 2~2.4 liter 4 cylinder to make up to (or around) 400HPish, but NOT ok for a 2.25 liter 4 cylinder trying to make 200HPish. It's not enough turbo??? Come on.

LEMHEAD16s' goal is 375-425HP. Most of these suggestions I'm seeing here are for double the power goals. Just think 2.25L 4 cylinder, and it's a pretty anemic little thing barely making 140HP. Just put 2 T25 or T28. Stock S13 turbos will be the cheapest and will EASILY get you 400HP. I would suggest going T28 (used S14 or 15) which is more than enough turbo for your goals, and when you get used to (or outgrow) the power, you can install GT2871s w/o any modification.

The only thing w/ the t25/28 is that at higher rpm, the internal wastegate can't handle the pressure and boost tapers. That's a problem with a little motor like the SR that NEEDS to rev to make power, but think double w/ the VH :chuckle:

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David Steele
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What! I'm not the only ''stupid one'' here ? ;)

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karay240 wrote:So let me get this straight. A T28 (or whatever's eqivalent) is OK ONLY for a 2~2.4 liter 4 cylinder to make up to (or around) 400HPish, but NOT ok for a 2.25 liter 4 cylinder trying to make 200HPish. It's not enough turbo??? Come on.

LEMHEAD16s' goal is 375-425HP. Most of these suggestions I'm seeing here are for double the power goals. Just think 2.25L 4 cylinder, and it's a pretty anemic little thing barely making 140HP. Just put 2 T25 or T28. Stock S13 turbos will be the cheapest and will EASILY get you 400HP. I would suggest going T28 (used S14 or 15) which is more than enough turbo for your goals, and when you get used to (or outgrow) the power, you can install GT2871s w/o any modification.

The only thing w/ the t25/28 is that at higher rpm, the internal wastegate can't handle the pressure and boost tapers. That's a problem with a little motor like the SR that NEEDS to rev to make power, but think double w/ the VH :chuckle:
The T2 flange turbo is a restriction on the KA24DE at anything more then 8 psi. They are better matched to the SR20 or smaller motors. People use them on the KA, but only because of how cheap the manifolds and supporting stuff from China is.

Also, the waste gate isn't what causes the boost to taper off at higher rpm with a T25. It's the tiny compressor not being able to support the volume of air. Which makes me ask, why go to the trouble of setting up a twin turbo intercooled system when you go in knowing that they are to small? I'm not a big fan of fabricating and investing in something that is 100% maxed out upon install. That's never a good plan IMO and running twins complicates the plumbing far more then necessary.

For the record, the T28's that make 400 whp on any motor in singular form cost about $1300 and have a T4 compressor. There are 100's of trims available for almost any combination but we're talking about what works well vs what can be thrown together. Especially if you're ok with buying a used turbo, the options are limitless for very good prices. Hell 2 RB25 T3 turbo's would be WAY better then SR T25's if you're stuck on twins.

Point being, there are so many great turbo's available right now, used, why not choose the best one (or 2) for the job?

WD

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WDRacing wrote:
darinz wrote:OK expert, I have a T04z ar 1.06. It is running 10psi. It has 2 psi at 2000rpm and hits 10 before 3000rpm and the boost creeps fractionally to about 10.5 by the current redline which is only 6000rpm as still on factory injectors and they are at 87% then. When the rev limit is reached the dyno graph is still basically a striaght line, boost is still constant and it has 375rwhp (at 6000 rpm without VVT switched either)
So here is a turbo spec'd for 850hp yet is providing very driveable power at under 600hp (flywheel).
So in your opinion I have an overly sized turbo that is a dog to drive. Funny that in reality it is extremely drivable with good power from 2000 rpm through to redline. It has a power band of 3500 rpm purely because I need to fit bigger injectors but can't as I've run out of money. Once it has new injectors

Power goal! What a load of crap. A power goal is for people who want to talk about how much power they have. What is impoerant is power derlivery and actual performance. My setup was spec'd with the goal of having power before 3000rpm and no restriction at 7500rpm. I argued that a turbo capable of 850hp was way too big and would give too much lag. BUT I listened to people who new far more about this stuff than I do and fitted this oversized turbo. All the books say it is too big but experience said it would work and it does. I have plenty of power and it is predictable and controlable. There is no surging, minimal lag and no restriction at the topend. (On the dyno it flew to over 7000rpm before we put limits on it)
So sure this is a competition vehicle but it is for offroad racing where power derlivery and control is far more important than outright power.

So before you start 'us guys' that we are just fitted randon turbo's, I suggest you read a few more books or actually listen to what people who have actually done it discover.
Slow your role dude. The power goals are very important when deciding on the turbo size and anyone that says different is simply ignorant. That's 100% Fact.

When you take into account the power goals you can match the compressor and exhaust housing sizes and wheel trims to give you the most power within your most driven rpm band. Ease up on the attitude and explain yourself like an adult and you'll find people actually listen vs just think you're a douche bag.

WD
Fair coment! I was a little hyped after reading several posts that just told everyone how great he is and basically no one else knows anything. So yeah I should have stopped and taken a breath before posting :blush:

So yes power goal is very important for specing the turbo (of course) but how the power is delivered ultimately is the important thing. eg no one wants a lag monster but equally you don't want the turbo to run out either.

My coments around power goal are to do with people who build dyno queens that look great on paper but in real world driving or competition, are real dogs.

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My car is used almost exclusively for Autocross, so any lag at all is not something I am interested in. I think a the T3/4 .50 trim that the KA guys use would be great for a twin turbo set up but I don't want to go that route just because of the complexity of plumbing everything twice.

Ideally I'd punch the motor out a bit, raise the compression a bit and slap a pair of heads on similar to Gerry's and have a solid NA machine. Either way turbo or NA, all these mods put me in a prepared/mod class that I would fail to be competitive in. I can't decide what I want more, a competitive car or a whole lot of horsepower. I'd like to run in ASP or BSP in the next few years but this car will never qualify for those classes.

I've also really been thinking about building a Locost lately.

thanks all for the input.

Josh

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darinz wrote: So yes power goal is very important for specing the turbo (of course) but how the power is delivered ultimately is the important thing.
That is probably the most accurate way to describe the perfect trim turbo. What unit(s) will provide the best power curve the most efficiently. For me a slight bit of lag can easily be sacrificed for a more efficient turbo when dealing with a V8 application. The immediate "out of the hole" torque is already present.

But if you don't want more power down the road the HC1 will probably work great for 8 psi as long as you have a waste gate large enough to keep the boost from spiking. No lag always brings a big smile ;)

If it was given to me I'd do it :dblthumb:

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David Steele
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WDRacing wrote: The T2 flange turbo is a restriction on the KA24DE at anything more then 8 psi. They are better matched to the SR20 or smaller motors. People use them on the KA, but only because of how cheap the manifolds and supporting stuff from China is.

Also, the waste gate isn't what causes the boost to taper off at higher rpm with a T25. It's the tiny compressor not being able to support the volume of air. Which makes me ask, why go to the trouble of setting up a twin turbo intercooled system when you go in knowing that they are to small? I'm not a big fan of fabricating and investing in something that is 100% maxed out upon install. That's never a good plan IMO and running twins complicates the plumbing far more then necessary.

For the record, the T28's that make 400 whp on any motor in singular form cost about $1300 and have a T4 compressor. There are 100's of trims available for almost any combination but we're talking about what works well vs what can be thrown together. Especially if you're ok with buying a used turbo, the options are limitless for very good prices. Hell 2 RB25 T3 turbo's would be WAY better then SR T25's if you're stuck on twins.

Point being, there are so many great turbo's available right now, used, why not choose the best one (or 2) for the job?

WD
You just hit peak power much sooner t28's they can do 270 whp and peak out at what 16 psi....that's stupid driveable.

Design the manifolds to see total exhaust pressure with an external w/g as opposed to some shallow angle and you're set.

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What T28's are we referring to just for reference? For the record I'm not against using a T2 flanged turbo on each side, I just prefer room to grow. I suppose the use of larger external waste gates will keep the boost from spiking. I'd have to know what T28 we're using in order to see how much volume the compressor will support. I mean if we're talking about the GT2876R then I'd be all about running twins, but those are over $1000 each.

Personally I'm a big fan of the single design and setup. A properly spec'd single will come on boost very quickly and provide more then enough room to grow. The simplicity factor also drives my preference. But that's just me.

WD

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David Steele
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I actually meant T25 not T28. (this is really pushing that turbo) of off a stock S13.

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Yeah I would never use T25's. The compressor is far to small and will be the very inefficient which will raise the output temps of the charge air quite a bit. The exhaust housing and AR size will definitely be a restriction at almost any amount of boost. If you're going to bother with running twins then you really should use something a little bigger.

There are way better options available then the SR T25.

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Yea, the SR20 turbos are not the end-all-be-all by any stretch of the imagination; however, it is the motor that probably has the most bolt-on applications on the market. Just about every major manufacturer (Garrett, IHI, Mitsubishi, and I think KKK) has their version of a bolt-on for the SR. I've installed many different turbos on KA's and SR's, and if you're not concerned about going passed 400rwhp (let's be conservative and say 600-700hp on a VH), then T28's are great. A little lacking in top-end, but incredible midrange.

That being said, you just can't beat the top-end from an externally wastegated system w/ a larger turbo. If 800+ is your goal, then the T28 is definitely not the turbo for you. If your goal is around 400 (as stated on the first post), and you have space constraints as most VH powered cars do, then the Tee-Too-Small is a very viable option. I'm not trying to say that the T25/8 is a "better" option, just saying that due to the space constraints, a relatively small internally wastegated twin set-up would be relatively easy and plentiful w/ room to grow.

BTW, I don't really get how ppl argue that the single turbo set-up is less complex. I'd rather rout charge piping around the engine bay than exhaust piping around the engine and other vital components worrying whether or not it'll get too hot.

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David Steele
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karay240 wrote: BTW, I don't really get how ppl argue that the single turbo set-up is less complex. I'd rather rout charge piping around the engine bay than exhaust piping around the engine and other vital components worrying whether or not it'll get too hot.
Unless you've done this conversion you'll find out that there is space there isn't anything to harm. Jeff Taylor used/uses a single turbo setup.

You'll find that domestic v8 turbo users use the simple '' cross over tube'' all the time in their setups.

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Bart
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I got 2 GT3071R's, good response but havnt dynoed yet. The SR20 guys use these, and the VH being almost 2 SR's it makes sense

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You might hit boost earlier with a turbo that is to small, but a properly sized turbo will make gobs more power with less boost.

Also...you don't use turbo's that have no top end on ANY racetrack.

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David Steele
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WDRacing wrote:You might hit boost earlier with a turbo that is to small, but a properly sized turbo will make gobs more power with less boost.
You are going against your earlier post.

Also...you don't use turbo's that have no top end on ANY racetrack.
Let's stop using sayings here that can get out of hand. Simply, if you want an X amount of HP you use ''this'' turbo.

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David Steele wrote:
WDRacing wrote:You might hit boost earlier with a turbo that is to small, but a properly sized turbo will make gobs more power with less boost.
You are going against your earlier post.

Also...you don't use turbo's that have no top end on ANY racetrack.
Let's stop using sayings here that can get out of hand. Simply, if you want an X amount of HP you use ''this'' turbo.
No, you're just not comprehending my point.

You go right ahead and use the SR T25's on the VH, IMHO it's far to small, not just on the exhaust housing side but the tiny compressor will be a heat pump. That's a bad thing. You'll heat soak your intercooler(s) very quickly. If you're lapping on a track you'll maybe make one full lap before the coolers are useless. Then you're either going to suffer from knock or you'll have to retard the timing a ton.

It's not as simple as X = #. There are lots of factors involved and frankly if you're going to invest a substantial amount of time and money into something you should do it right. Just because you can do something doesn't mean you should.

Everyone has there own idea's and whatnot. Personally I think the T25 is a very pour choice considering what the intended use of this vehicle is and the readily available alternatives.

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My experienses with turbo on the lexus 4 litre v8:

A friend of mine runs the uz engine with a hks t51r turbo with the biggest exhaust a/r availiable.
It spools up extremly fast, and har a ton of torque alredy at 2500-3000rpms.
Its the most drivable engine I,ve ever experienced, and thats a BIG turbo.

Another guy here in norway runs tvin gt 2871 turbos on the 1uz and has even better spoolup (off course)

But the engine hits a wall at 6000rpms due to small turbines...

If you put a gt2871 turbo on a sr20 engine it will give you a real blast up to at least 7500rpms,
but it doesent work the same way with two turbos on a engine twice the sr20 size...

This is based on my experience, and not my technical knowledge with turbos.


Right now Im building a JDM VH41 egine for turbo, and its getting a single 4094 with the biggest ex a/r avaliable.

Im 100% sure this turbo will give me a very responsive engine with a wide powerband up to 7500-8000rpm.
I actually traded in my new 4088r 82ar for 4094 1,16ar.
Atp turbo and Mazworx told me that the 4088 would only give good power to approx 6500 due to the small ar housing.

You can run two t25s with the vh45 and it will super responsive, but if you want to run the engine effective over 5000rpm
you will get dissapointed...

Run a big turbo or turbos and you will still get a responsive engine and a good powerband up to 7-8000rpm,s.


No matter if you,re running 5psi 400whp, or 25psi 700whp BIG will be the best solution.

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Carl H
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strap on the 'small' gt42...equivalent to the hks t51r kai.
did the math and its BEAUTIFUL on the VH.

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Carl H wrote:strap on the 'small' gt42...equivalent to the hks t51r kai.
did the math and its BEAUTIFUL on the VH.
The compressor is probably perfect, what exhaust housing size were you looking at?

Side note...while looking for info on the GT42 I came across some "Dang that's sweet" new stuff from Garret. I need to remember to keep up because there are some new compressor wheels and housings that look awesome and promise way more efficiency for their size.

Damn things are all over $1500 though :facepalm:

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t3/t4 50 trim x2 =fun

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^ :yesnod

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LEMHEAD16 wrote:t3/t4 50 trim x2 =fun

I had looked at that! Liked what I saw too! :)

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so would a pair of gt30r work well @ 600hp @ 7500rpm or would gt28r be better?

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I have a T04z with 1.15 rear housing on my vh45 it works well.
A friend of mine has a vh45 with gt3540 Australian ford falcon xr6 turbo internally gated and his made 440bhp on 8psi.
Hope this helps

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Carl H wrote:strap on the 'small' gt42...equivalent to the hks t51r kai.
did the math and its BEAUTIFUL on the VH.

Sorry to bump this thread, but its better than starting a new one. I'm looking at a gt4294r same as the gt42 Carl H suggested for my stock vh45. Im able to get one new for a very good price but the a/r is 1.44

I know its been said in this thread to go the biggest a/r you can but is 1.44 to big?

Thanks Guys

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Ok so bear with me here so make some log manifolds that drop the turbos down rather than right next to the block is there room otherwise where is threre room To hide them mabey where aiv used to be im determined here im searching for anything but a front mount

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A single turbo mounted remotely would solve all of your underhood space problems.


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