Lets think bigger turbos!

[valmes]

I am in a process of deciding for a bigger pair of turbos for my VR-4.

After some researching It came down to either pair of GT2530 (which are kind of pricey!) or a pair of “old style” Garrett T3 turbos for a more reasonable amount of money.

Playing with various formulas, turbo matching programs and compressor maps I came to a conclusion that a pair of Garrett T3 (60 or 50 trim and .63 or .48 exhaust A/R) will be quite a good match to our engine. They can provide almost 60~70 Lb/min (900~1000 cfm) of “rated air flow at 2PR” (or roughly at 1 bar boost pressure) and most of the points for our engine lie in the 70% of compressor efficiency for up to 1,5-1,8(!) bar of boost, with 5000-7400 range getting into max compressor efficiency at 1bar (74-75%). The best part of it is price! Remanufactured T3 go for 400-600$! New ones are from 700$ and up… Compare those prices to GT2530 that start from 1500$! *(prices for a single turbocharger)

GT2530
(+): They can provide good amount of airflow and generally believed of being capable of a wider “usable range”, can spool up fast (there are no exact figures… but everyone keeps saying so…). Utilize a new ball bearing design and use a ceramic compressor wheel…
(-):They are hard to repair, and the “new design” is more prone to failures… ceramic compressor wheels are less durable then the old style steel compressor wheels and ball bearing turbos require modifications to oil supply lines, since they are quite “sensitive” to oil pressure and are less tolerant to heavy loads (then old style turbos). Price is also a set off…

T3
(+): Good flow. Can be remanufactured. Cheap. Tolerant to abuses.
(-): Will probably lag more then GT2530 and are not of the “new design”.

PS: Either of those (pair of)turbos can safely produce 450-550 BHP on our engines with a maximum power closer to 700 BHP. That is, if everything else can cope with that kind of power!

PS2: I hope this information could be helpful to someone out there… and hope I didn’t make too many mistakes ! I am no “turbo expert”, so take this information at your own risk .
Looking forward to get input from Real Experts on this matter…

[-LegnumVR4-]

I've been chatting to a turbo guy about a setup for the VR4's. Came up with the Garrett T25's (not sure they are the samething as the GT2530) they are the same ones used on the 300zx. He's said that the T25's are a good turbo u can customize to suit the engine as they have a lot of areas u can move to fit large compressor wheels, bearings etc, and they are compact.

The guys in the US know alot about the Garrett turbos so they can be sourced from there and built to what u want. Maybe jump on a US 300zx fourm to get info.

[enigma]

Very interesting! I too have come across the GT25s as a good match, but as you say they are not cheap! T3s I think are the way to go, just need someone to stop messing around and make a manifold now......... :$

[valmes]

Lack of custom made manifolds is what stopping VR-4s from going up in price!

One place replied with a quote of 800$ per side!!! :rolleyes5 Will have to search more... or fabricate them on my own using either old ones (manifolds) or getting set of extractors from NA 6a13 and welding T3 flanges on them. Have to find a good welder first though...
(May be "BDA fabrication LTD" is up for a job?)

Another option is to use custom made adapter plates (this option seems to be cheaper and easier to implement) to fit those T3 turbos to our stock manifolds... but there could be some "spacing" problems... I/C piping will also require some mods (in either option).

[-LegnumVR4-]

Can u weld to cast iron?

I have a rear manifold here, all u would need to do is trace the outline and holes for the bolts and get it lazer cut. I can get the outline if anyone needs it or even lazer cut.
I also have the gasket for the T25 here, can do the same for that as well to give u and idea of sizing. I would say making the custom manifold wouldn't be very hard at all, big Dave can handle that easy, just sorting out the position where the turbo is to mount to it. I found for the rear turbo u want to keep it close to the engine and towards the brake pump to allow enough room for a 2.5 or even a 3" dump pipe

I haven't spent much time with the front turbo, looks like it wouldn't be too much problem there

U could pick up some cheap second hand turbos and recon them, just as long as the housings etc are fine and not cracked. Make up the oil and coolant lines from braided lines for easy fitting.

[valmes]

Guidelines for Welding Cast Iron

[enigma]

If I was going to make manifolds it would be stainless flanges cut one for the block and one for the turbo, then custom bent stainless tube to make a pretty manifold!

The flanges would be about £75 for the lot and the tube would run to maybe £50. It would be very easy in my opinion and when my engine is out and on the stand in the garage............

[valmes]

So, how much would be the total for custom made VR4 exhaust manifolds (front and back) with T3 flanges with BDA sign on them?

"HKS Stainless Steel tubular turbo exhaust manifolds offer maximum exhaust flow for increased turbo spool up & phenomenal flow capacity. Fabricated of polished SUS304 stainless steel and flanged to mount an HKS wastegate for unsurpassed boost management."

"DC Sports Turbo manifolds and Competition Pipes are available in 100% T-304-stainless steel only, and are for use on Off-Road vehicles only (not C.A.R.B. exempt)."

Whats 304 stainless steel anyway?

[AllBeItMine]

you guys ever look at the TD04 9 or 13g's as a viable option? They come out of the GTO's (9'gs) and GSR's(13'gs) and in new zealand you can get them second hand for about $200nzd each.

As for manifolds, i would say you would be looking at a complete custom job as you would most likely need to mount the turbos closer to the engine to get them to fit.

[valmes]

Turbos rated at 2PR:

Stock VR-4(6a13) - 275CFM
TD04-9B - 275CFM
TD04-13G - 360CFM
T3 60 trim - 490CFM

None of the last 3 turbos are "bolt on" replacement.
They all would require custom made manifolds and mods to your downpipes.

Apart from just CFM numbers you really have to look at CompressorMaps to get a picture of what to expect from them...

Hope this answers your question. The rest is up to you!

[AllBeItMine]

Turbos rated at 2PR:

Stock VR-4(6a13) - 275CFM
TD04-9B - 275CFM
TD04-13G - 360CFM
T3 60 trim - 490CFM

None of the last 3 turbos are "bolt on" replacement.
They all would require custom made manifolds and mods to your downpipes.

Apart from just CFM numbers you really have to look at CompressorMaps to get a picture of what to expect from them...

Hope this answers your question. The rest is up to you!

You think the TD025's (stock 6A13) and the TD04 9g's flow the same? that can't be right. the TD04's are a visually much bigger turbo, let alone the actually specs.

I would think the TD025's would flow nearly 275cfm at decent boost.

here is a map of the TD04 13g http://www.stealth316.com/images/td04-13g-raw.gif

[valmes]

Look at the CMap of 9bs and plot demand lines/dots for our engine, you will see the how close they are to our stock units.
Some TD04 perform better then TD05, so do overlap other families and brands of turbochargers. So why are you surprised that our TC03 units flow same amount, as bigger 9bs from GTO/3000GT?

There is still no definite answer as to what our turbos are. On 6a12 engine the turbos are clearly marked as TD025 and they do look very much like ours (6a13)... but others (like people in Majestic Turbos) said they are actually TC03 family turbos.

PS: I am not saying this information is 100% correct... use it at your own risk

[-LegnumVR4-]

http://www.pro-art.co.jp/rosso/kouza/legnum.html

Scroll down the bottom u'll see what turbos we use. Can use a translater program to read the other info.

[Mante]

Not to derail any ideas BUT after thinking of a very similar car by nissan that is also 2.5L and AWD..the skyline most owners dump the twin setup for nicely sized Single turbo application. Say if a quick spooling 20g such as the Buschur 20g A single setup would be much cheaper to setup/install and most importantly TUNE.

This specially modified TD05/6 Hybrid 20G is the quickest spooling 500+ HP turbo we have ever run. It has run 10.70's at 130+mph and made 450hp to the wheels with our proven combinations... all without the aid of nitrous! This was the turbo we used to run the first-ever 10sec blast in an AWD DSM! Tym Switzer - 10.98@124.79 1991 Eagle Talon - Full weight, full interior, full exhaust, etc. August 1997 Please see part #'s 60040-BR and 60050-BR on this page for Porting and Clipping options.

[valmes]

Not to derail any ideas BUT after thinking of a very similar car by nissan that is also 2.5L and AWD..the skyline most owners dump the twin setup for nicely sized Single turbo application. Say if a quick spooling 20g such as the Buschur 20g A single setup would be much cheaper to setup/install and most importantly TUNE.

I agree, for I6 (Nissan Inline 6 cylinder twin turbocharged engine - RB26DETT) it is cheaper and easier to go single turbo. What we have (in VR4) is a V6 setup! Twin turbo here looks like a better option! ... at least for me .

PS: On the other hand, FTOLTD went for single turbo due to space restrictions (fitted 6a13 V6 into FTO!!!) and with some great results!!!

[enigma]

Looking at the turbos on the engine that came out of my car, 2 bigger little ones is a better option. I was also thinking you could leave the rear one and go for a bigger front one for sequential boost? :rolleyes5 Its probably best to have a matching pair though!

[Mante]

I agree, for I6 (Nissan Inline 6 cylinder twin turbocharged engine - RB26DETT) it is cheaper and easier to go single turbo. What we have (in VR4) is a V6 setup! Twin turbo here looks like a better option! ... at least for me .

PS: On the other hand, FTOLTD went for single turbo due to space restrictions (fitted 6a13 V6 into FTO!!!) and with some great results!!!

Yes I know very well we have a V config lol..jeez give me some credit :-D and I was also thinking of ftoltd's good setup when thinking of switching to the single setup but using a more effective turbo and the idea of not having to use nitrous to spool it. Im considering the br20 for one reason, well two 1. its the quickest spooling 20g that i have come across and 2. while being well into the eff. range it will produce upwards of 450 whp. All figures were taking from the eclipse 4g63T (2.0L I4) Guesstimating having a 6a13 at the same would be pretty easy...

[zentac]

Look at the CMap of 9bs and plot demand lines/dots for our engine, you will see the how close they are to our stock units.
Some TD04 perform better then TD05, so do overlap other families and brands of turbochargers. So why are you surprised that our TC03 units flow same amount, as bigger 9bs from GTO/3000GT?

There is still no definite answer as to what our turbos are. On 6a12 engine the turbos are clearly marked as TD025 and they do look very much like ours (6a13)... but others (like people in Majestic Turbos) said they are actually TC03 family turbos.

PS: I am not saying this information is 100% correct... use it at your own risk

Before fitting my engine I checked the numbers on my turbos they are definatly TC03-06A

[valmes]

Yes I know very well we have a V config lol..jeez give me some credit :-D and I was also thinking of ftoltd's good setup when thinking of switching to the single setup but using a more effective turbo and the idea of not having to use nitrous to spool it. Im considering the br20 for one reason, well two 1. its the quickest spooling 20g that i have come across and 2. while being well into the eff. range it will produce upwards of 450 whp. All figures were taking from the eclipse 4g63T (2.0L I4) Guesstimating having a 6a13 at the same would be pretty easy...

Didn't mean to offend anyone. Sorry if it sounded this way.
We just have plenty of cars here with 1JZ-GTE, 2JZ-GTE and some RB26DETT who are also going single turbo setup from twin turbo, 'cause it's easier to setup on an "inline" engine. As I was told, placing turbos closer to cylinders is essential to getting hotter exhaust gases with more velocity, hence more power can be utilized!!! With single turbo on any V shaped engine exhaust manifold will have a pretty long runners(extractors) - which is a downside!
FTOLTD sure did make a good single turbo system out of 6a13 engine, but I am sure somebody will eventually come up with at least similar or even better performing twin turbo setup! Again our engine bay is a little less space restrictive than that on a FTO. IMO... BTW can you give a link to "Buschur 20g" CMap?

I was also thinking you could leave the rear one and go for a bigger front one for sequential boost? Its probably best to have a matching pair though!

Won't running differently sized turbos of different engine cylinders unbalance the engine? Different amount of load on front and rear(of V shaped engine) due to different exhaust restrictions?
Sequential turbo is also more complex design, since you have to figure out how to make one turbo switch over to another one... Like with fuel pumps - running differently sized fuel pumps in parallel setup is not recommeded...

Here is what RX-7 owners (who have stock sequential twin turbo) say about benefits of converting to non-sequential twin turbo:
"- There will be considerably less vacuum lines to worry about, and you will no longer need the 2 black vacuum and pressure tanks which will provide larger paths for air to flow around the engine cooling it more and helping to prevent the baking of underhood vacuum lines and components.
- A smooth consistant, predictable boost curve that will come on strong and stay there through redline unlike the stock 10-8-10 PSI mess. This smooth boost curve means you no longer have to worry about the transition point occurring during a corner (which could and sometimes does send the car into a tailspin)
- Less restrictive exhaust path, which ultimately results in less backpressure being seen by the engine (IE more power, and less internal heat)
It will become trivial instead of impossible to troubleshoot problems with the turbo system (if you have any "
some relevant info


2 zentac - One more in favor of TC03!!! :-D

[Slimshady]

Whats 304 stainless steel anyway?

304 Stainless is the grade (this is related to the amount of carbon atoms and also the amount of chrome used in the manufacturing of the steel)

304 Stainless is basically a bog standard stainless & almost oxidisation free (note almost) all steels will oxidise - leave this and the same in conventional steel at the bottom of an ocean and both will oxidise (rust over time) – the 304 will last considerably longer but will oxidise over a long period of time.

The best stainless you can buy for money is 316 – this is basically surgical steel and if looked after, will not oxidise (unless you leave it at the bottom of an ocean for a lot longer than the other two).

Note 316 is a fair bit more expensive but worth it if you are in the medical trade (in fact I am not sure if you can use anything else)

Be very careful when ordering stainless steels – the surface grain quality is appalling (unless you order BA sheet) I certainly would not use it as a bulk head or gasket – if so I would specify polished finish or BA sheet if this is applicable for the application – note this will cost lots and lots. Also be careful if you are laser cutting stainless, the edge finish can also be bad – water or plasma cutting can give a better finish but will also cost more. Specify a clean and de-burred finish.

Also if you are not sure if it’s stainless – get a magnet – if it sticks its mild steel


Well if your still awake - that’s enough of metrology 101 for now – more soon


Slim