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Location:
Brisbane
Registered:
November 2002
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Turbo manifold design
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Thu, 06 May 2004 23:41
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Hi guys
I have a 1JZGTE for which I am getting a custom turbo manifold made up. I am using a CT26 due to fitment and budget reasons. This will be hiflowed down the track, with the aim of getting approx 420-450hp crank.
I was just wondering what people's thoughts were on manifold design in this specific situation.
I have not really dealt with this much, but my general understanding is that larger diameter or longer runners suit top end, and smaller diameter or shorter runners are better for response. Please correct me if I'm wrong, as I said I'm a bit of a newbie on this particular topic. Also I'm sure that's a little bit too general... how big is 'big' and how short is 'short'
The car is actually using an automatic gearbox, so I have no real concerns about it being a little sluggish to build boost. Main thing is that I don't want to compromise top-end performance, as I want the thing to rev out to redline with no dramas (anyone with a 1JZ will know that the stock twins start to lose puff at about 14psi and 6100rpm).
If anyone has examples (pictures would be helpful), suggestions or theory on the subject, please let me know!
I am also considering doing an 'upside-down' manifold, I was wondering if anyone had experience with this. A friend was going to do it but was concerned it might trap heat in the general turbo area.
Cheers
Leigh
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Location:
nz
Registered:
July 2003
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Re: Turbo manifold design
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Fri, 07 May 2004 00:41
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hi i did the same thing to my supra 1jz sum time ago I have to say i really dnt think a ct26 turbo is suited to a 1jz even when h/flwd they are 2 small on the exhaust side when i made my manifold i used 1.5 inch steam pipe and equal lenght runners of about 200mm each on refection 1.25 may have been better if u are on a budget make a 2 into 1 adapter frm fact manifolds as short as pos but with smooth intergration to collector 4 ct26 I recomend using apair of t28 of rb20s or twin tdo4 turbos with adaptors from fact manifolds these should be cheaply availible and provide descent flow and responce from 4000 rpm onwards having said all that if u want 420+ hp the fact twins with custom dump pipes and good tuning are capable of this if boost is kept to about 1bar they last ok aswell I think that in the long run u wont be happy with the result the ct26 will give hp that helps
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Location:
On your mum!
Registered:
May 2002
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Re: Turbo manifold design
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Fri, 07 May 2004 05:00
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1 1/4 steam bends or 1 1/4 stainless mandrel bends will be good for response. You wont be wanting for too much response though as the turbo that you are running is very small (IMHO) for the 1J.
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Location:
Adelaide, SA
Registered:
May 2002
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Re: Turbo manifold design
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Fri, 07 May 2004 05:37
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Leigh since you have a manifold already (bit rudimentry but workable), and a flange for a mazda series 5 exhaust housing I'd suggest doing what Sean and I had planned for that mainfold - clean up the ports, weld in a split pulse divider (S5 housing is split-pulse) and weld the S5 flange onto the existing CT26 one.
Mazda Series 5 turbos are cheap, have a BIG exhaust housing that is still internally wastegated and can be rebuilt with T04 parts fairly cheaply (for a turbo anyway...). As long as you don't get one with a back-cut exhaust wheel the response should be good and you can fit a T04 front cover and compressor wheel on them.
You can find them pretty cheaply on the ausrotary forums.
It'll have more lag than the twins, but with the right exhaust wheel probably less than a CT26, and far more opportunity for flow at the top end. I actually bought a near new hybridised turbo with this setup (but a ford sierra turbine wheel) rated at 500-600Hp but sold it as I'm selling my car. This turbo is now on a 250 ford motor and boosts almost off-idle.
Cheers,
Caelum
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Location:
On your mum!
Registered:
May 2002
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Re: Turbo manifold design
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Fri, 07 May 2004 05:42
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I doubt if you will get less lag than the CT26, they are (in my exerience) very quick in the response dept. I do however agree that you should be looking in the direction of a larger turbo.
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Location:
Adelaide, SA
Registered:
May 2002
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Re: Turbo manifold design
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Fri, 07 May 2004 06:32
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OK less lag was a bit ambitious  Although if you get the right turbine wheel design and size you could do a lot to reduce the lag.
But considering the modify-ability and exhaust housing size of the series 5 rx7 turbo I think it is a much better choice than the CT-26.
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I supported Toymods
Location:
melbourne.victoria.austra...
Registered:
June 2002
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Re: Turbo manifold design
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Fri, 07 May 2004 07:01
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ok, ideally the smaller the dia of the pipe, the faster the response. i'm using schedule 40 1.25" steam pipe for mine - i got a 90 degree bends and half a meter of pipe to go with it for $45 - good value.
ideally a well cut header plate is a good idea also. respective flanges for the turbos can be had from several places, mine cost $40 for a t03 style flange for my rb20 turbo.
i'm not sure of the logic on a 6, but my 4AGE collects 2 and 3 and 1 and 4 - i'm working near a simple log design because of space constraints and the weld els are hard to work with also.
you could look at a stainless steel setup - remember to factor for the different expansion rate of the stainless - example the outer studs to hold the manifold to the head make the holes slightly larger otherwise you'll crack them.
ideally you want to also go for equal length runners, whilst you won't notice it really on the street by the looks of things you're looking for hi rpm so this will help somewhat ; again only marginally but every bit counts depends on how much room you have to work with and turbo mounting position - again stainless would be easier to work with here. equal length runners will also help with heat dissipation, typically the exhaust temps increase as the gases are collected together 1 to 2 to 3 to 4 - for example, by the time the gas is at cylinder 4 its prolly 600 degrees (example) hotter than the exhaust gas at cylinder 1.
um, try and keep the turbo drain pipe straight down OR go against no more of an angle that 30 degrees - otherwise you could end up with flow back to the sump issues. remember the restrictor in the banjo bolt for the oil feed - as turboes don't need much oil pressure for lubrication - 1 - 1.2mm seems to be the ideal for my rb20bb turbo.
i'm not sure on your upside down idea though, do you want to hang the turbo off the flange plate (facing down) or do you want your flange plate facing upwards?
hope my waffle has helped.
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Location:
On your mum!
Registered:
May 2002
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Re: Turbo manifold design
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Fri, 07 May 2004 07:18
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GCG have told me that they can fit the GT30 internals into the CT26 - that's pretty modifiable. I would rather go and get the whole turbo than modify the bejeezus out of the Toyota/Hitachi item.
Just my thoughts anyway.
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Location:
Brisbane
Registered:
June 2003
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Location:
Adelaide, SA
Registered:
May 2002
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Re: Turbo manifold design
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Fri, 07 May 2004 13:31
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FYI slylux on these forums has put a stock and hiflowed CT26 on a 1jz and detailed his results somewhere.
If you were going to the bother of getting a complete turbo manifold built, you'll need to decide internal or external wastegate as well. It may be cheaper in the long run to buy a complete single turbo "kit" for the 1jz - manifold, turbo and wastegate rather than muck around with bits'n'pieces.
What about the single turbo's off a VVti 1jz? They're cheap, and if you change either compressor or turbine wheel (memory fails as to which one right now) will develop some good Hp on the 1jz.
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Location:
Brisbane
Registered:
November 2002
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Re: Turbo manifold design
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Sat, 08 May 2004 04:19
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Hi guys,
Thank you for your suggestions. The reason I am not using the twin-single manifold I already had (and have since sold) is that, due to the placement of my steering, I am unable to run an exhaust. At all 
While I am making a custom manifold, I am still operating on a budget. I'm sick of fucking around and am just after something simple that will provide a bit of a laugh. I already own the CT26, so this is the turbo that I will be using for now.
Additionally, I've had nothing but problems with cars in the past, so I just want something modest. I could get 600hp out of a 1JZ without so much as a problem, but it is neither a practical nor financially sound idea.
Think of it this way:
* My Supra ran consistent high 13's
* It was running a CT26
* It was bolted to a tractor engine
* The Supra was 1600kg
Now:
* I want the Mark II to run consistent high 13's
* It will be running the same turbocharger
* It will be bolted to a modern engine
* The Mark II is over 200kg lighter
Applying a bit of common sense suggests that I will most likely achieve my aims - possibly even before the turbo is hiflowed or I need to upgrade the injectors.
The only other thing I would consider is, instead of using a CT26, to purchase a 450hp Garrett GT28 (internally gated). Again, this would not use a 1JZ to it's full capabilities, but response should be awesome along with 400-450hp at top end.
These are about $2300 - if I sold the CT26 for $300 and put aside the $950ish for the hiflow, it would really only be an extra $1,000 for this upgrade (given that I'm already getting the custom manifold, exhaust, etc).
Again, budget comes into play.. is this $1,000 worth spending?
Leigh
[Updated on: Sat, 08 May 2004 04:21]
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Location:
Australia
Registered:
September 2002
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Re: Turbo manifold design
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Sat, 08 May 2004 06:17
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I know where you can get a nice hi flow CT-26 from in the near future:-)
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: Turbo manifold design
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Sat, 08 May 2004 07:48
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"anyone with a 1JZ will know that the stock twins start to lose puff at about 14psi and 6100rpm"
on stock twins I ran 16psi of boost, and it happily made power until 7400rpm!
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Toymods Board Member
I supported Toymods
Location:
Turramurra, Sydney.
Registered:
May 2002
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Re: Turbo manifold design
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Sat, 08 May 2004 08:45
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If consistant high 13s are what your aiming for, why get rid of the stock turbos? In a MkII I would expect high 13s with a stock standard 1j, & mid to low with exhaust & 'cooler plus a little boost.
With just the exhaust & big intercooler a bargearse cressida can do consistant high 13s.
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: Turbo manifold design
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Sat, 08 May 2004 09:12
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I believe the engine was bought without the stock turbos, which is the reason for the ct26 (uber-cheap turbo).
that said, I'd be tempted to look for a set of stock twin, which seem to come up for sale fairly regularly as people dump big turbos on their 1jzs
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Location:
newcastle
Registered:
June 2002
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Re: Turbo manifold design
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Sat, 08 May 2004 10:49
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i cant agree more with stock twins a good diff and a good boost controller  intercooler .the corona could easily run into the high 12s.
surley you can pick up a set of stock twins for around $500 or less in good cond .
i agree a turbo upgrade would be better but considering the budget . you really cant go past stock twins
ill be running my wifes cressdia on the quater in next few weeks and expect to be able to run high 12's with the cressida weighing 1580kg. the corona would easily do this .
special ed has run 13.3 with similar mods and a manual in a jza70 Supra
Just a thought anyway
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Location:
u.s.a. south
Registered:
April 2004
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Re: Turbo manifold design
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Sat, 08 May 2004 18:24
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ct26 with 10 or 15° clipped turbine wheel regularly put down 450hp with garret 60 trim or 60-1 compressor wheels in machined ct26 comp housing. The internal wastegate regulates fine. A common low cost upgrade.
I'd think it would do about the same on a 1j as it does on the 7m.
I make runners short as possible and converge to the collector. 1.25" steam pipes, no cracking. I try to avoid any 90° bends.
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Location:
On your mum!
Registered:
May 2002
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Re: Turbo manifold design
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Sat, 08 May 2004 23:50
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Internal wastegate will control boost fine - if you are running lots of boost. If you are trying to regulate it at lower boost pressures (ie every day) you will most likely find that the small internal gate of the CT26 will struggle.
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Location:
Brisbane
Registered:
November 2002
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Location:
Brisbane
Registered:
November 2002
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Re: Turbo manifold design
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Sun, 09 May 2004 06:19
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Unfortunately it is impossible to fit the stock twins as the rear turbo will foul the steering box.
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I have just been looking at the car, and for the first time looked into the engine bay with the wheels at full lock to the driver's side... where the f_ck does your exhaust go Dave??
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: Turbo manifold design
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Sun, 09 May 2004 06:58
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It goes out between the steering box shaft and the block - really high! There's enough room for 2 2" pipes. You may have to ovalise your dump pipe, or posssibly run it a long way back, almost behind the steering box.
I'll take some pics (from above and below) and email them to you - is the turbosupras.com email addy still good?
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Location:
Brisbane
Registered:
November 2002
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Re: Turbo manifold design
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Sun, 09 May 2004 07:23
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Interested to see
Check your PM...
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