Turbo what size? need suggestions

With Turbo and Super charging you can create massive horsepower with vw motors.

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WLD419
Posts: 79
Joined: Tue Nov 08, 2005 12:09 pm
Location: suburbs of miami fl.

Turbo what size? need suggestions

Post by WLD419 » Fri Dec 29, 2017 11:42 am

Hello ,
This is my first turbo build ,
I've been collecting parts for a type 4 Turbo , when it comes to figuring out what Turbo to get, I could use some help input , I've been reading (maybe to much :lol: ) still can't figure out what I need :shock: , I'm thinking 10-12lbs boost :?: ,so I say at moment :lol: , I'm thinking 9.0 CR +- ? ,water meth inj. or maybe E85 , plus air to air intercooler (easier to setup)
this is going into a 914 , I'm looking for turbo that will come on boost after 3800 ( don't want to cruise on boost/cruise is 3200-3500 ) maybe I'm thinking this wrong ?
I have collected so far ( 5+ years collecting or hoarding :lol: parts )

2.5 litre
100mm nickies with JE pistons
80mm 4340 forged crank ( was 71mm chevy jour./picked up an aa 80mm on black friday :) )
cb 5.325 h-beam rods chevy journal
1700 W case (decked ,machined for cylinders,drilled for 1/2" bolts ,& a few other mods )<br/><br/>
1700 heads with 42x36 ss valves (vw650 springs & ti retainers) plus machined step groove between cyl. & head

1-7/8 4-2-1 CFR Tangerine exaust , will modify with flange coupling for turbo ( its probably to big but its what I have to work with ,its on my running 2.8 ) dont want to hack it, still using it,

pauter cam K8O3 on 110* LC, in. 288* adv. /255@.050 x .384 lobe lift , ex.296* adv. /268@.050 x .398 lobe lift
type 4 rockers 1.3 with porsche adj.

putting together a HORIZONTAL fan shroud system (I picked up a incomplete kit )
MS2extra with twin 48mm throttle bodies

Turbo ?
waste gate ?
thanks in advance Bill D.
Bill DeWitt
2800cc 914-4
TwinPlugs & MegaSquirted
Weekend Therapy :D

Clonebug
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Joined: Fri Feb 16, 2007 12:28 am

Re: Turbo what size? need suggestions

Post by Clonebug » Fri Dec 29, 2017 1:47 pm

What is your hp target????
What is the hp of that engine N/A????
What is the max rpm you plan on turning it???

Turbos only boost when under load for the most part so not wanting boost until 3800 rpm is not a good match for the street.
The last thing you want is to have to rev the crap out of it to get boost.
Getting a little boost at 2400-2800 rpm is sweet because that is where most VW engines like to run. It really improves mid range torque and that is what you want on a street driven car.

You want to size the turbo for your targeted hp at the rpm and airflow required to support it. If you go too big with the turbo then you will have lag at the lower end. Get too small of a turbo and you will not reach your targeted hp or reach the new targeted hp because you keep turning up the boost from your newfound addiction........Ask me how I know......... :roll: :wink:

I use this calculator to figure out how much hp I want and the airflow required......once you know that you can pick a turbo from either the junkyard, Craigslist, swap meet or Ebay and make it work for you.
You can also order one from the experts if so desired.

http://www.rbracing-rsr.com/calcboost.html

So...lets punch in some numbers. I found the defaults are off slightly but they are close enough to get started.

fill in the blanks on the turbo calculator as follows

Peak hp 300
AFR 12
BSFC .55 this is a default number YMMV
Charge temp 130* F.
VE. .95 Also default
Peak RPM 5600 I guessed at this for you
Disp in CI. 153 your engine

Boost required is 17.96 lbs.
33 lbs. /min of air is required for the 300 hp
408.94 CFM for desired hp.

If you want to change any of the boxes go ahead......see what changes it makes with different rpm, air temps or peak hp.

Now you know you need a turbo that puts out over 400 cfm......every turbo seller will know the flow capability of each and every turbo.....if they don't....walk away....with a quickness

My turbo will flow 394 CFM and 270-290 hp so it is on the small side for you. A Subie STI turbo would be just about perfect if you could find one in good shape for cheap.....they are available when those guys need to upgrade due to their addiction issues.
STI turbos are good for about 350 hp.

My turbo has an upgrade available that will move it to 330 plus hp support by replacing the compressor wheel and housing with a -19T wheel.
If you can find a WRX turbo cheap and then get that upgrade at $250.00 you would be set.

This is all based on if your target hp is 300 plus or minus.
That 914 would be a handful at that power output.
In fact.....I almost guarantee you would be happy as a pig in mud with that combo......
Keep in touch when you get closer.......I seem to collect the WRX turbos.
Where are you located in this big world???
Stripped66 wrote:The point wasn't to argue air temps with the current world record holder, but to dispel the claim that the K03 is wrapped up at 150 HP. It's not.

carsten bb
Posts: 34
Joined: Sat May 19, 2007 3:00 pm

Re: Turbo what size? need suggestions

Post by carsten bb » Fri Dec 29, 2017 3:37 pm

Hi
Nice combo.
Is the cam specs correct? Maybe backwards?

You could have å nice 500hp engine with the correct turbo.
I would look into Precision turbos, and not junkyard turbos.
Go large on the wastegate, if you get a modern turbo.

Carsten

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theKbStockpiler
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Re: Turbo what size? need suggestions

Post by theKbStockpiler » Fri Feb 23, 2018 6:56 pm

Clonebug wrote:
Fri Dec 29, 2017 1:47 pm

My turbo will flow 394 CFM and 270-290 hp so it is on the small side for you. A Subie STI turbo would be just about perfect if you could find one in good shape for cheap.....they are available when those guys need to upgrade due to their addiction issues.
STI turbos are good for about 350 hp.

My turbo has an upgrade available that will move it to 330 plus hp support by replacing the compressor wheel and housing with a -19T wheel.
If you can find a WRX turbo cheap and then get that upgrade at $250.00 you would be set.

I thought you were using a T3/T4?

I was looking into a TD04hl-15 but the consensous is that is drops off a lot after 5,000 RPM. Do you find that this is true?
Super beetle with attitude

Clonebug
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Re: Turbo what size? need suggestions

Post by Clonebug » Fri Feb 23, 2018 8:10 pm

I do not have a T3/T4.

I have the TD04L-13T....not the TD04HL.

They are somewhat the same but still different.

The turbine wheels are different and I think the center section might be a little different too.......
I have only run the Subaru turbos.
2 IHI turbos from the older Gen 86-87 GL-10 Wagons and the current 2002-2007 WRX/Forster turbo I now have.

I'm not up on what the TD04HL turbos come on or what hp they will support. I think Volvo used that turbo and most Volvo turbos have a Recirc BOV built into them and won't reclock very well.
I used the 32# injectors off a 94 Turbo Volvo and they were good to 230 hp at 100% DC so I would assume the turbo was able to support about the same amount and maybe a little bit more if all OEM's are the same and not overbuild their vehicles.
I have maxed them out and now run 45# injectors at about 73%.

I have had my TD04L at 24.3 lbs boost but after putting an intercooler on it we could only get it to put out a max of 20.5 lbs boost when on the dyno.
I haven't had a chance to explore that issue due to it being a buggy and the weather going to pot since then. I also have driven through the Stage I clutch and need to upgrade to a Stage II.

I plan on putting in a new clutch in the next few weeks but it's too cold in the garage to mess with it right now.
Last edited by Clonebug on Fri Feb 23, 2018 10:07 pm, edited 1 time in total.
Stripped66 wrote:The point wasn't to argue air temps with the current world record holder, but to dispel the claim that the K03 is wrapped up at 150 HP. It's not.

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buguy
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Location: Port Orange, FL

Re: Turbo what size? need suggestions

Post by buguy » Fri Feb 23, 2018 10:02 pm

I think when I was researching it the HL was larger than the L like we have. Here is a thread I found when I was looking that showed some of the differences. You have to scroll down a bit to get to it. http://www.superturbodiesel.com/std/sho ... p?tid=4043

Clonebug
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Re: Turbo what size? need suggestions

Post by Clonebug » Fri Feb 23, 2018 10:28 pm

buguy wrote:
Fri Feb 23, 2018 10:02 pm
I think when I was researching it the HL was larger than the L like we have. Here is a thread I found when I was looking that showed some of the differences. You have to scroll down a bit to get to it. http://www.superturbodiesel.com/std/sho ... p?tid=4043
I have researched so many OEM turbos I can't remember exactly what each one flows. If I remember correctly the TD04Hl-15 was about the same flow numbers as my turbo but it has a heavier turbine wheel and therefore will spool a little slower....along with the slightly larger -15 compressor wheel it might put out slightly more CFM but is not worth it for me due to slower spool and loss of lower end torque and power for the slight gain in top end.

The TD04L-13T will support 270 hp. I assume that is crank hp due to most WRX's being listed as about 215-220 whp max at stock settings.

There is a lot of info if you just type in the specific name of the turbo you want to research. Take your pick.... :wink:

As I said...I only look into Subaru turbos due to the excellent results I have gotten from them. Until those turbos won't supply my needs I plan on sticking with them......I still can try an STI turbo which will support 350 hp.
Once I have exhausted their capabilities I plan on trying a Holset turbo.....If I ever go that far...... :? 8)
Stripped66 wrote:The point wasn't to argue air temps with the current world record holder, but to dispel the claim that the K03 is wrapped up at 150 HP. It's not.

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