Big boost turbo's

[GARRICK.CLARK1]

Think I read the TEE pipe was best for draw through in the turbo mania book.

[V8Nate]

I thought I remembered reading as well that somebody did some testing and found that a Y would unevenly pressurize one side vs the other which really doesn't make much sense but I like you buguy do remember reading that

[Steve Arndt]

It isn't the pressure. On draw through the Y causes uneven fuel distribution. The T mixes and distributes the A/F more evenly.

[V8Nate]

Makes sense:)

[GARRICK.CLARK1]

Went to the turbo shop today to see how my hybrid turbo job is doing.
He did find an oil leak into the exhaust housing so is fixing that with an updated seal kit. The cold side wheel is bigger than the old one, maybe 10mm bigger, was hoping for something bigger really, the housing is a better 1 than I have as it has the anti surge channels built into it, Just hoping its gunna be a successful power upgrade, at least the oil leak will be done.
The 10mm wheel increase must equate to a 25% size increase which must be 25% more air. I'll look at the part number to see what it is, pick it up on Thursday.

[buguy]

Just have to give it a try. Might be perfect for you!

[GARRICK.CLARK1]

Hey up dub tuners, does anyone port the cold side aluminum casing Inside diameter out pipe. My new casting is 42 mm and the Tee pipe is 51 mm. I should be able to take it to 48 mm at least. Or does it not matter.

[bug66]

If the Y is straight after a bend it won’t work, someone can google it, but I think you need ~15 inches after a bend for the air to distribute itself inside the pipe

[slowsixtyduece]

Hey up dub tuners, does anyone port the cold side aluminum casing Inside diameter out pipe. My new casting is 42 mm and the Tee pipe is 51 mm. I should be able to take it to 48 mm at least. Or does it not matter.

As long as there are no places that need to be smoothed that would restrict air flow, I would leave it. If I’m understanding it right, it’s not creating any sort of ‘disturbance’ like it would be if it was the other way around (ie: air flowing from large pipe to small pipe with a step).

Mine is the same way - the turbo housing ID is about 43mm, and the pipe to the intercooler ID is 50mm. There might be a slight pressure loss due to this jump but it’s so negligible it’s not worth the extra time.


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[GARRICK.CLARK1]

Ok roger that guys I'll leave it, I do have a TEE pipe which is being replace by a smooth flow Y pipe, There is a straight pipe leading up to the Y pipe so that's good.
I also have the 2" boost pipes going in the hats HORIZONTAL, motor runs fine but wondering if boost blowing DOWN from the top would be better.

[buguy]

I wondered the same thing when I was building my plenums. Only advantage I heard about is being able to bias the flow to one of the cylinders over the other. I'm not convinced it makes any difference either way. At least at my performance level.

[GARRICK.CLARK1]

So Tuning for more power.
Been reading more on it , and it seams to me once all is done to your motor its then all down to CFM. probably all down to CFM from the get go.
Starting at the turbo, If the turbo hasn't got the CFM capabilities then upping the boost psi is pointless. Next is the intake ( if using carbs ) What CFM the carbs will flow
Then on a type 4 anyway , what the exhaust ports will flow as the inlet ports are already good at flowing air.
If I was to do it all again ,I'd pick the turbo 1st then get the heads, intake , exhaust to be capable of flowing the air that the turbo can produce.
The CFM TO HP EQUATION IS
1 HP PER 1.45 CFM, so if I want 400hp the intake needs to flow 580 cfm and the turbo needs to flow the same amount of air as well.
40 dells flow 266 cfm. IS this number per butterfly, and at what vent size
If per butterfly , and with there being 4 of them, that's 1064 cfm in total. Seams a lot. If this is correct 40mm carbs are more than enough for most VW engines

[buguy]

There is definitely some voodoo in figuring this stuff out. Someone has the math, but I don't know it. It seems to me you have to have a goal in mind with what you want. As you said, it all has to work together. Also dependent on how you want the power. You certainly could get a turbo that flows 1000 cfm, and get heads that match, and make a intake with the volume needed, but it might need to spin 8000 rpm to be in the right range to make power. If it's a road car, you might want power to come on quicker and have to run a smaller turbo etc.. Figuring out the balance has to be tough.
And I agree. With dual carbs or dual TB's they always seem like they are way bigger than necessary. I may be looking at it wrong though?!

[GARRICK.CLARK1]

So, bit disappointed really, Got my turbo back from having it rebuilt and modified. The original size was
45 - 60
NOW ITS 45 -61
To be fare its the biggest cold air housing that was compatible with my old one.
So not really a big jump up on the cold size. Cold wheel is about 25% bigger.
The cold housing is a better one with a 3" inlet ,the old one was a 2" inlet. Also has a proper threaded boost fitting for the wastegate.
Its got a V CLAMP fitting on the out pipe ,are there universal clamps and flanges to buy ,like just measure the size and go from there.
He has fixed the oil leaking into the exhaust so that's good

[gbaker770]

I went from a Y to a T and found no difference in AFR’s. Pretty much identical according to the LM-2. I also went from end castings to plenums on my big motor years ago and found it had a little worse throttle response.
The older I get the less I care about little things like that. Usually a small twist of the boost knob makes up for stuff.