Which Junkyard Throttle Body to choose

[gregs78cam]

Soooo...... I am getting things and ideas organized in preparation of building a MultiPort Intake, I spent a few hours in SolidWorks, and have some good ideas on runners and plenum, but I wanted to ask everyone what their preferences are on throttle bodies. I want to know what vehicle I need to rob, er uh, acquire one off of. I looked briefly on Feebay, and don't want to spend $150+, but want something that will support the 425HP I have now AND have a compatible flange/bolt pattern for upgrading if/when I add a turbo or two. At this point I am not even considering a 4bbl type. Mostly monoblades.

[RobertISaar]

IIRC, the N* throttle bodies are 75mm units. you'll want a 96-up unit to get away from the ISC motor though.

not sure if that's big enough for you, in theory it should flow ~636cfm.

a twin 52mm TPI/LT1 unit flows ~850-900 cfm. twin 48 are roughly 800.

[1project2many]

Mpfi8.jpg

1100 cfm marine TB with staged blades and GM TPS/ IAC? :)

[EagleMark]

Next time your in town stop by, I have a 4 barrel holly or a big one barrel brand new like jeepsandguns is using.

Ideas I had for mounting fuel rails involved a one piece TBI adapter extended to hold fuel rails in place...

[gregs78cam]

I guess I should add a little more info. My current iteration of this is looking a bit like the RAMJET 502 intake.....with injectors mounted in the valley....

1100cfm from 2bbl. COOL, but I have no idea where to find one.

[EagleMark]

LT1 has an aftermarket 52mm and 58mm
http://www.google.com/products/catal...ed=0CFMQ8wIwAA#

You could probably machine a JY one and make new butterfly's.

[1project2many]

1100cfm from 2bbl. COOL, but I have no idea where to find one.

Why, the boat junkyard of course!

Or...
http://www.ebay.com/itm/MerCruiser-I...228e7d&vxp=mtr

http://www.ebay.com/itm/MerCruiser-T...db1976&vxp=mtr

Cheaper!
http://www.ebay.com/itm/Mercruiser-T...3213fa&vxp=mtr



This looks cool, too.
http://www.ebay.com/itm/Mercury-Raci...7ff0ca&vxp=mtr

And this:
http://www.ebay.com/itm/BBK-03-07-DO...6c617c&vxp=mtr


If you've got the cash, this is a good deal:
http://tampa.craigslist.org/pnl/boa/2852754040.html

Look around the 'net for boat junkyards. They exist. Also check classifieds on marine sites. Sometimes people are selling EFI because they think they can get more power from a carby setup. That TB picture is from a system I have here at the house. I put another into a truck a few years back:
tpitruk3.jpgtpitruk4.jpg

[EagleMark]

There used to be a boat dismanteler in Carlin bay. But around here boats last so long do to short boating seasons and fresh water it is usually old stuff.

I used to buy and sell boats, since we have some very large lakes here we also have some big boats. Do to short boating season and fresh water they were in excellent condition with low hours at 10 plus years old and sold over on the west coast like hot cakes...

[1project2many]

I visited a boat junkyard once and was surprised at how many boats were damaged in the back. "But boats only really travel forward." Then I saw one on a trailer and realized what was happening. It's damage from tailgaters, not damage from boating.

[EagleMark]

That could be apparent! But when boats loose power at sea, or at lake the bow stays in wind and they travel backwards into shore and rocks as well...

[gregs78cam]

So this is what I have been working on this morning. I can redraw the front end to match whatever TB I use.



I have been looking real hard at one of these......
http://www.ebay.com/itm/270932406422...84.m1438.l2649

http://www.ebay.com/itm/102mm-CNC-Th...c57863&vxp=mtr

[EagleMark]

Way to cool!

Could do something completly differant and put a TB on both ends? Rear fed through firewall to cowl area... front CAI somewhere. Don't just put a K&N airfilter on it as it messes with intake air from fan etc...

[gregs78cam]

Way to cool!
Don't just put a K&N airfilter on it as it messes with intake air from fan etc...

Never. That will be routed to fresh cool dense air. OR compressed cooled air, eventually.

[gregs78cam]

Well, it took way too many hours, but this is just about the final model. I still have to decide how to do the back of the plenum, and then the valley, and then the water jacket/neck.....it just doesn't end.

[1project2many]

Whatever you choose, try to ensure it uses a decreasing radius throttle arm. The largest percent changes in airflow through a TB occur at the lowest throttle angles. With a constant radius, especially if it's a fairly small one, this means the engine wants to snap to life when you try to leave a light, or an intersection, or when you're trying to cruise at low speed. Sounds like fun but it can get tiring when you have to constantly work to prevent the tires from breaking free and pay attention to not pushing the throttle too hard.

my $.02.