TURBO Q & A FORUM

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Grinder
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Re: TURBO Q & A FORUM

Postby Grinder » 29 Jan 2010 23:40

L24 510 wrote:Yeah! I finally got thew the 19 pages of thread and get to post my questions that have not been answered yet. I have always been interested in turbos and want to build a draw threw turbo set up. I learned heaps of information from reading this but still need to go get a good turbo book, that ill do tomorrow. So here's my plan I want to build a LZ22 (L20 block Z22 crank) With ported u67 head. This is in a street car and i guess i want to get about 7lbs of boost. My goal is about 175 power. what compression is recomended 8:1 :?: I plan to fab all the piping my self as to make it compact and custom. But im wondering what is the reason that all turbos i see are mounted horizontally :?: In my setup I want to mount it vertically with the turbine outlet facing down so i can put a carb right on top of the inlet. Is this possible or is there some reason because oil flow that a newb like me doesnt know :?: Also from most of what i read i get the feeling that people are using weber style carbs. I was thinking i could just get a 300-400 CFM holley and plop it on top of the turbo :?: Then jetting and such are easy as pie because for a holly there is a hole mess of different parts. I look forward to your responses and cant wait to start building this thing.
Scott


If you are looking for a good turbo book I'm just reading Corky Bell's "Maximum Boost". Its an excellent reference to get you a good solid understanding of turbo systems. It helps he's Datsun born too ;)

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Wicked Saint
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Re: TURBO Q & A FORUM

Postby Wicked Saint » 03 Feb 2010 07:05

I am trying to get together a setup for my L16 and I have found by reading that I will need a rising rate fuel pressure reg so as not to drain the bowl dry and lean out as poost rises. My question is this, I see fixed 1:1 ratio regs and adjustable. Whould I conceivably need an adjustable for my L-series or if I transplant a KA in the future?

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Re: TURBO Q & A FORUM

Postby 510rob » 03 Feb 2010 10:23

DON'T use a rising rate regulator - you don't want any mechanical gain in the system. The carb needs to see a constant pressure differential between atmospheric pressure and fuel pressure. For an example Weber DGV, the fuel pressure needs to be 3.5psi above whatever atmospheric air pressure you surround the carb with ("inside the box" pressure).

Also, a blow-through L16 turbo setup is sooooo different than what a KA24 EFI setup needs, that they aren't really even comparable... ...I am forced to assume you are talking carbs on the L-series because it's such a pain in the ass to fuel inject an L-series, and I am also forced to assume you are referring to a fuel injected KA because why would you put carbs on an already fuel injected motor, right? (sorry Duke, sorry Julian)

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Wicked Saint
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Re: TURBO Q & A FORUM

Postby Wicked Saint » 03 Feb 2010 11:24

510rob wrote:DON'T use a rising rate regulator - you don't want any mechanical gain in the system. The carb needs to see a constant pressure differential between atmospheric pressure and fuel pressure. For an example Weber DGV, the fuel pressure needs to be 3.5psi above whatever atmospheric air pressure you surround the carb with ("inside the box" pressure).

Also, a blow-through L16 turbo setup is sooooo different than what a KA24 EFI setup needs, that they aren't really even comparable... ...I am forced to assume you are talking carbs on the L-series because it's such a pain in the ass to fuel inject an L-series, and I am also forced to assume you are referring to a fuel injected KA because why would you put carbs on an already fuel injected motor, right? (sorry Duke, sorry Julian)


This will be for a single Weber 40DCOE draw through system. I thought if your fuel pressure was too high at idle you would flood your bowl and spew gas and if you did not have that rising rate in place that as the boost rises your fuel pressure would not be adequate to flow enough gas to keep up with demand. So the plan in my mind was to team the rirsing rate reg with an electric inline pump ensuring I will have enough fuel at all times. As far as the KA swap is concerned I just want to be able to use as many components as I can minimizing long term costs. I know the fuel pump would be reused but I know nothing about fuel regulation. If I have the all backwards please let me know. I look forward to your input.

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okayfine
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Re: TURBO Q & A FORUM

Postby okayfine » 03 Feb 2010 12:21

510rob wrote:a fuel injected KA because why would you put carbs on an already fuel injected motor, right? (sorry Duke, sorry Julian)


Hey, don't look at me, I have a carb'ed SR! :lol:

ROB EDIT - yeah, exactly - you took off the EFI!!! LOLWTFBBQ!!!?!?!?


Wicked Saint wrote:As far as the KA swap is concerned I just want to be able to use as many components as I can minimizing long term costs. I know the fuel pump would be reused but I know nothing about fuel regulation.


The EFI KA will need a high-pressure fuel pump (43psi). Likely not what you're going to use for an carb'ed L-series turbo. If you're going KA, why the intermediate stop at an L16T?
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson

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Wicked Saint
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Re: TURBO Q & A FORUM

Postby Wicked Saint » 03 Feb 2010 12:52

okayfine wrote:The EFI KA will need a high-pressure fuel pump (43psi). Likely not what you're going to use for an carb'ed L-series turbo. If you're going KA, why the intermediate stop at an L16T?


When I 1st got the car about a year ago I found a turbo manifold, turbo, and carb for sale on Craigslist but had never finished gathering goods to finish it. I plan on a swap down the road but I figured if I could set it all up and get it running then when I do make the swap I could sell the turbo system as a working kit and have some fun in the mean time.

Or if you prefer the short answer.

I didn't plan ahead and now I have a half completed project. :roll:

p.s would a Walbro 255 not suffice for both applications?

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okayfine
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Re: TURBO Q & A FORUM

Postby okayfine » 03 Feb 2010 13:23

Wicked Saint wrote:Or if you prefer the short answer.


Long answer is always better. Getting your setup running to sell as "known good" is the smart way to go.

Wicked Saint wrote:p.s would a Walbro 255 not suffice for both applications?


For the high-pressure EFI application, yes. For a low-pressure application, I don't think so. A high pressure pump may not be happy regulated down so far, though if you can contact Walbro and see, you could be good to go (though you'll need to add a fuel pressure regulator).

Low pressures relative to L-series carbs are no greater than 3-4psi. EFI runs 43psi.
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson

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McShagger510
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Re: TURBO Q & A FORUM

Postby McShagger510 » 03 Feb 2010 20:51

The old set up I used on my blow through L18 was this:

- 280ZX turbo pump - mounted in the back (first tried the noisy Holley Blue pump - no good)
- modifided Holley regulator - heavy spring, top screw removed for a brass 90 for a manifold pressure line,
regulator is set for 3.5 psi, pressure on demand when boost rises
- 32/36 Weber carb - plastic float, big inlet valve and secondary jet
- return line back to tank - in line 'pill' restrictor with small hole installed just before the tank

example: If you run 10psi boost you will need to supply 13.5psi for the system to work.

This combo worked with some sorting and help from Keith, to produce 185 HP at the wheels! :lol:
Nothing ventured, nothing grained! - Benjamin Franklin

'72 2dr. 510 Turbo
'73 240Z all stock
'71 2dr. 510 stock......for now
'91 Nissan truck
'78 Kawasaki Z1-R
'84 Kawasaki GPZ750 Turbo
'99 Kawasaki ZRX1100

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bertvorgon
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Re: TURBO Q & A FORUM

Postby bertvorgon » 03 Feb 2010 21:26

If you are using a DRAW through system, as long as the VOLUME of whatever fuel pump and lines are adequate, a normal fuel pressure regulator for that carb is all that you need.

A draw through system is just like any naturally apsirated motor, requiring the normal VOLUME of fuel delivery, that any high performance motor would need. Volume of fuel delivered, is usually the culprit when upping the anty on power, and that is where the trouble comes from. You MAY, want to go up one size in needle and seat, but, I would just sneak up on things. I WOULD get a good wide band A/F meter...THAT will just save you so much time, and, possibly a motor.

Our blow through systems are a whole different ball game, when boost comes up.

You will set your static fuel pressure, at whatever is recomended for that carb. My sponsor on my Datsun had a "killer colt" suck through motor, on his Datsun 1200, which made 300 Hp at the time. It used the Holley 500 CFM carb.

I used to run against a fellow that had a converatble 510, with a suck through a Weber 2.0 l. It was dead simple, made reasonable power, and had the simplest of water injection on it.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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Wicked Saint
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Re: TURBO Q & A FORUM

Postby Wicked Saint » 04 Feb 2010 06:58

Great info, Thanks guys.

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heirfaus
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Re: TURBO Q & A FORUM

Postby heirfaus » 11 Mar 2010 14:32

So I'm finally going to make an attempt at getting these final steps in my turbo project done. I need to buy a wastegate and am not sure how to choose the sizing. Any ideas on how to decide what is best for an application?
"An intercooler...has never been, nor should ever be, considered icing on the cake. A proper intercooler is more cake."
Corky Bell, Maximum Boost

"one of the little things that add up"
-defdes

510rob
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Re: TURBO Q & A FORUM

Postby 510rob » 11 Mar 2010 15:25

Hi Chris,
fast answer...

big turbo, big boost = small wastegate is fine...
big turbo, small boost = you need a BIG wastegate...

if the turbo itself isn't killer huge, then you shouldn't need a big wastegate.

Most guys are running 35mm or 38mm wastegates.

Keith and James both use the Turbonetics Deltagate II (with a 35mm valve)

If I were to buy a wastegate right now, I'd get a Tial MV-S simply because they are very compact, and v-flanges are nicer than multi-bolt flanges...

http://www.tialsport.com/NewHotness.html (scroll down to the MV-S Wastegate)
http://www.pfabrications.com/inc/sdetail/1336 (good picture of the wastegate)

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heirfaus
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Re: TURBO Q & A FORUM

Postby heirfaus » 11 Mar 2010 16:29

510rob wrote:big turbo, big boost = small wastegate is fine...
big turbo, small boost = you need a BIG wastegate...


Wait, what? :?

Doesn't that seem counterintuitive? Wouldn't a large turbo and large boost need a large WG. Did you type that correctly. I bet you did, I just don't quite understand that.

T3 60 trim planning for 5-10 psi

Edit:

I think it just hit me. A big turbo with low boost means it has to dump ALOT, right?
"An intercooler...has never been, nor should ever be, considered icing on the cake. A proper intercooler is more cake."
Corky Bell, Maximum Boost

"one of the little things that add up"
-defdes

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heirfaus
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Re: TURBO Q & A FORUM

Postby heirfaus » 15 Apr 2010 13:20

Well I think I almost have all the parts for my turbo setup. My question is about intercooler piping. I have some aluminum 4" piping I was going to use, but then I realized the turbo output is about 2 inches and throttle boddy is about 3 inches. Should I really use a big diameter pipe and use a reducer? Isn't this counterproductive? won't the air have to re-compress? Wouldn't it be better to buy some piping that is the same diameter as the throttle body?
"An intercooler...has never been, nor should ever be, considered icing on the cake. A proper intercooler is more cake."
Corky Bell, Maximum Boost

"one of the little things that add up"
-defdes

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bertvorgon
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Re: TURBO Q & A FORUM

Postby bertvorgon » 15 Apr 2010 13:55

Actually, I would use 6" sewer pipe....that way it will take a week to build boost...and you will not scare yourself.....

I have always felt, that keeping the piping about the same size, just keeps the volume to be pressurized as minimal as possible. I use the 2" out of my turbo to the intercooler, then 3" into my air box( which is a stupidly short run anyhow). Not like we all have some sort of high boost, full race motor, that really only needs to see the Mulsanne straight at 150+ MPH.

What is the discharge size coming out of the intercooler?
Attachments
turbo3 (Medium).jpg
2" in, 3" out
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer


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