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]

1926

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....:rockon:

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/catalog?hl=en&safe=off&q=lt1+throttle+body&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&biw=1280&bih=567&wrapid=tlif133150761472410&um=1&ie=UTF-8&tbm=shop&cid=7680096270378826062&sa=X&ei=pzFdT6CJNJPaiQLtzMGYCw&ved=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-Intake-Plenum-P-N-805240A1-805243A-4-/320648416893?pt=Boat_Parts_Accessories_Gear&hash=item4aa8228e7d&vxp=mtr

http://www.ebay.com/itm/MerCruiser-Throttle-Body-P-N-805243A12-NLA-/290377636214?pt=Boat_Parts_Accessories_Gear&hash=item439bdb1976&vxp=mtr

Cheaper!
http://www.ebay.com/itm/Mercruiser-Throttle-Body-and-Sensors-805243A2-Item998-/190475015162?pt=Boat_Parts_Accessories_Gear&hash=item2c593213fa&vxp=mtr



This looks cool, too.
http://www.ebay.com/itm/Mercury-Racing-Mercruiser-HP500-HP525-TPIS-Mono-Blade-Throttle-Body-/250961981642?pt=Boat_Parts_Accessories_Gear&hash=item3a6e7ff0ca&vxp=mtr

And this:
http://www.ebay.com/itm/BBK-03-07-DOGE-VIPER-67-MM-THROTTLE-BODY-LLMORE-MARINE-1767-/380380143996?pt=Motors_Car_Truck_Parts_Accessories&hash=item58906c617c&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:
19301931

[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.

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1932&d=1331582428

I have been looking real hard at one of these......
http://www.ebay.com/itm/270932406422?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

http://www.ebay.com/itm/102mm-CNC-Throttle-Body-GM-GEN-III-LS2-LS6-/150773004387?pt=Motors_Car_Truck_Parts_Accessories&hash=item231ac57863&vxp=mtr

[EagleMark]

Way to cool! :happy:

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! :happy:
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.
http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1977&d=1331629058http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1983&d=1331629259http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1980&d=1331629058http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1982&d=1331629259

[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.

[JeepsAndGuns]

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.

Heres my findings when I was searching for a TB for my MPI build.

We discussed in this thread several options, and found out a single large blade flows more air than a two smaller ones.
http://www.gearhead-efi.com/Fuel-Injection/showthread.php?301-MPI-throttle-body-options

I took a clear easy to read ruler with me to the pull a part junk yard and measured a few TB's. I found the 99 and older cadillac northstar tb's have a 73mm blade. The 2000 and newer ones have a 75mm blade. I purchased one of the 00 northstar units witch are just a mirror image of the LS1 tb's. After some trial and error, it was just gonne be too much work to use it, with throttle cable being the biggest part.
I measured several 96+ vortec tb's and all the ones from the 4.3 were 73mm, and had a large air deflector on the underside of the blade. I did find one V8 vortec tb, I noticed the air deflector on the underside of it was half the size of the ones on the 4.3. I measured it and the blade was 75mm. I purchased this tb and I'm using it.
The tb itself has a slight taper under the blade, so I had a machine shop remove the taper so its a straight 75mm all the way through. I then removed the deflector from the blade, but was left with two large holes where it was attached. I then saw the unused northstar tb I had laying there and tried the blade out of it, it fit perfectly and had no holes in it. I just had to slightly slot the holes to match the screws in the vortec shaft.
I have a pic of mine in my "getting closer" thread in the gear heads section.

Nice intake btw.

[RobertISaar]

Whatever you choose, try to ensure it uses a decreasing radius throttle arm.

i take it this is the EFI equivalent of a carb with progressive linkage?

[1project2many]

i take it this is the EFI equivalent of a carb with progressive linkage?

Yes, and even more equivalent to progressive with small primaries.

BTW,Greg, any idea how plenum volume compares to engine displacement on this manifold?

[RobertISaar]

http://mysite.verizon.net/vzezeqah/id1.html

that intake article is about the extent of my knowledge for intake design.

"V8's with one large plenum feeding all 8
cylinders does not work all that well as far as the
Helmholtz resonator goes, but if this is the case, plenum
volume should be about 40-50% of total cylinder
displacement. "

"If a boost is desired in a higher rpm range, closer
7000-7500 rpm, the plenum will need to be 10-15%
smaller. To get a boost in the 2500-3500 rpm range, it
will need to need about 30% larger. "

[EagleMark]

Wow that is a great article! It's in pdf as well!
http://mysite.verizon.net/vzezeqah/sitebuildercontent/sitebuilderfiles/inductionsystems.pdf

Greg came by and grabbed my 75MM single barrel Vortec/LS type TB. He's going to do some measurements and drawings for future but not sure if he is going to use it. Just about the same thing as jeepandguns ended up using.

[gregs78cam]

WOW, lots of questions......


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.

Yes, I completely agree, I experience this everytime I drive the Camaro. I would like to use one that is progressive opening.


BTW,Greg, any idea how plenum volume compares to engine displacement on this manifold?

Well funny you ask. I have been reading alot over at yellowbullet, and studying John Marcella's manifolds (pure works of art - www.yellowbullet.com/forum/showthread.php?t=127750 (http://www.yellowbullet.com/forum/showthread.php?t=127750) ), and from what I have read, a good rule of thumb is plenum should match engine displacement. As I was finishing it up last night, er, this morning at 1AM, I decided to check the plenum volume and as it is drawn it is 382.49 cu.in., engine is 385. So during the previous changes to the model, when I had changed the inlet to plenum, and added 1/2" at the back to better contain the runners, I ended with it just about spot on. Runner length and volume will depend on whether I blend the runners into the plenum, or leave them all the same length and flare them inside the plenum. I was shooting for about 6" runner length as that is what the RPM AIR-GAP I have now is supposed to be. As they are drawn they will be between 7" and 9".

Thanks for the info. I need to read all these links and go over the formulas for it. But this is what I love about modeling it first, I can combine available parts with what the design needs and can revise it as many times as I need to get it right, before a single piece of aluminum is cut.

[dave w]

Maybe the option of a late 90's Vortec 454 Throttle Body? U-Haul used the same throttle body on the Vortec 8.1 liter truck engines. The pics are from a 99 454 Vortec.

dave w

[EagleMark]

That throttle body looks just like the one he got from me except no hole in the throttle plate. It measured 74.xx bore on intake side.

[dave w]

That throttle body looks just like the one he got from me except no hole in the throttle plate. It measured 74.xx bore on intake side.

Probably is the same throttle body. I posted the pics to show how the factory kept the intake runners long, with a low profile. The pics also show how the factory was able to increase plenum using the lower plenum for some "free" volume.

dave w

[EagleMark]

It's notworthy to mention the throttle body itself is in middle of intake plenum on the vortec, earlier versions like TPI and LT1 are on front! I had suggested earlier that 2 smaller throttle bodies one on each end would be cool since he is making this from scratch, but seeing how technoligy and design has changed over the years with GM it may be more then just a cool design and unique built intake! Since the vortec is fed in middle makes more sense then one end, I really wonder if feeding from both ends would be even a step above just middle?

If you look at some fomula car engines they are all single injector and single throttle blade fed air. But revving up to 14k rpm is another world...

[gregs78cam]

Yup, those are some really long runners. I like the packaging, but I don't know if I want that long of runners. With the setup I have on the car right now, the added plenum volume of the dual TBI adapter did raise the top end of the engine a bit. It pulls easily to 6K now instead of hitting a wall at 5500, and that is what I was hoping for. I think the design I have so far is going to work really well. I am very happy with the runner size, shape, volume, and injector placement. I may need to put more taper in the plenum from front to back. I just wish I could find shorter injectors. I am watching some on Ebay, but wow, they are expensive. It looks like you can't give away 24lb'ers, but I need 40+lbs. Do you happen to know what the 8.1L injectors flow? I haven't found any concrete numbers.

[dave w]

Do you happen to know what the 8.1L injectors flow? I haven't found any concrete numbers.

I did a homemade flow test of the Vortec 454 injectors using a stop watch and a large cc syringe, and came up with about 19 lbs at 45 psi (3 samples on each of the 8 injectors). The '7730 ECM I used to run the Vortech 454 on the stand seemed to like about 20 ~ 21 lbs for injector flow. I don't know what the 8.1 liter used.

dave w

[JeepsAndGuns]

While on the subject of dual TB's, ever pay attention to the gen 1 vipers V10? They had two TB's, one on each side feeding each cyl bank, and they were tied together with a shaft to make them both open equily.

[gregs78cam]

While on the subject of dual TB's, ever pay attention to the gen 1 vipers V10? They had two TB's, one on each side feeding each cyl bank, and they were tied together with a shaft to make them both open equily.

The Nissan VG30DE in my avatar was the same way. It adds to the complexity but may be cheaper to get two smaller TB's from pullNsave.

[EagleMark]

Well you seem to do everything dual? :rockon:

How about 8 one barrel TBI units hooked to a LT1 sequential PCM? No plenum!

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=2009&stc=1&d=1331946901

[RobertISaar]

it also looks infinitely more awesome. :)

[EagleMark]

This may give the idea, it was a post by Six Shooter and would cover our DIY Dyno as well...


http://youtu.be/5OS_k0V8Bvw

Injectors on top of velocity stacks?


http://youtu.be/h2jTKNHNr8g

[RobertISaar]

1. that is ridiculous, and i want SO BAD!!!

2. i bet the injectors above the throttles is due to a couple of reasons, #1 being it won't mess with an optimal intake tract. #2 i would assume it would allow better use of the engine's fuel as a coolant for the air charge. possibly better atomization?

[EagleMark]

If you noticed later in video it is all enclosed, well bottom half of air cleaner is there to cover it all.

[Six_Shooter]

The only reason injectors are placed close to the valves is for driveability and emissions. For high power and high RPM applications placing the injector higher in the runner (without a lot of bends) will get the fuel suspended more evenly in the intake charge.

I still love that video of the guy "driving" the engine, in the test cell.

Now they have computers that run the engines to simulate being on a track:

http://www.youtube.com/watch?v=o_QyUD6V5_I

[1project2many]

The only reason injectors are placed close to the valves is for driveability and emissions.

Yep. Low rpm operation allows more time for fuel to be heated and subsequently to vaporize. When fuel vaporizes it expands and as it expands the gas tends to displace oxygen needed for combustion. The complications of wet flow manifolds haven't really disappeared. Placing injectors in the plenum of a large intake, away from the runners can cause the manifold to become fuel saturated at idle and low speed and can cause it to behave like an old carby engine with the float level too high. Additionally vapor handling is a big deal for OEM applications and a plenum with unburned fuel hot soaking in the summer sun is going to require a well thought out strategy to prevent excess evaporative emissions unlike a race car used offroad only. At 6k plus rpm fuel delivered by an injector is drawn into the cylinder in very short time, vapor handling isn't as important, and race manifolds can usually have injectors placed wherever they choose. But for us street guys it's usually safer to select a location closer to the valves.

I've always liked listening to this one:
http://www.youtube.com/watch?v=aRMpi1esjoQ

[EagleMark]

:laugh: I could only take 50 seconds of that and was laughing so hard I woke the wife up... WOT was great!

So it's the low RPM, that's why the F1 cars idle in pits at like 6000 RPM... guess there's no issue with manifold getting wet at 12,000 or so RPM. One video said piston was traveling 300 times per second!

[daleulan]

My dyno lab isn't quite as nice looking but that's basically how I have my lab set up - the computer drives the engine. For steady-state calibration I can do it manually. For emissions testing on the three cycles I test on (HDDT, WHTC, ETC) the setpoint data is at 1 Hz; it looks like about 20Hz setpoint data on this dyno to get the time resolution down for those fast gear shifts. That's quite an impressive fuel cloud above the injectors.

For transient fuel control, injecting right by the intake valve is nice. Not only for emissions but to make transient calibration easier. For starting, though, I liked throttle body injection. It was much more forgiving. I recall being frustrated when I first needed to do gasoline start calibration at -40 with multipoint - lots of wet plugs during the calibration. I resorted to firing the plugs a dozen times per TDC to keep them dry 'till I got the calibration close. Much more spark than that and the engine runs on electricity... I could only do three cold starts in a day because it was just in a cold room. Probably should have rented a glycol chiller and forced the issue. For natural gas (the fuel I mostly tune to) multipoint is only an emissions and backfire advantage - basically the feedback from the O2 sensor is faster because of reduced transit delay and there's less fuel to ignite in the intake for when it decides it wants to spit back. That last point is especially important if you have a plastic intake manifold. I punched a pretty big hole through one of those plastic GM Vortec truck manifolds one time. If you have fuel film issues with natural gas then you have other difficulties in getting the engine to start - like oil viscosity.

[1project2many]

:laugh: I could only take 50 seconds of that and was laughing so hard I woke the wife up... WOT was great!

lol. Hope you weren't drinking the morning coffee when it started.


there's less fuel to ignite in the intake for when it decides it wants to spit back. That last point is especially important if you have a plastic intake manifold. I punched a pretty big hole through one of those plastic GM Vortec truck manifolds one time.

The aftermarket supercharger kits that have a supplemental injector at the TB can do the same thing, and for the same reason. I once worked on a truck which had been modified for more airflow and the aftermarket injector controller was no longer supplying enough fuel. Snapping the throttle at low boost resulted in a pop which was small enough, luckily, to blow the plastic plug out of the back of the intake without additional damage. I never found the original plug though.

I once spent a month trying to work out a cold start issue on TBI with a customer's car back in my beginning days. The engine had to sit for almost 6 hrs before it would occur, and it never happened above 10 degrees. I had only the weather for cooling so I got one start in the morning and one in the evening. No WB display back then, NB wasn't warmed up, 160 baud ecm, and much less understanding of the code than these days. What a long and frustrating job that was. I would have given up my toolbox for a cold room. :)

[gregs78cam]

So to run this thing I am thinking I want a '94 or '95 PCM, as that will be able to do both sequential fire and control the 4L80E. Would it also be possible to do DIS? I guess I need to re-read the DIS thread. I think it would be sweet to have a cam sensor mounted where the distributor "used to be", and have the DIS coils mounted above that at the back of the manifold. A crank trigger would be easy to work in.

EDIT:

I don't know why it didn't occur to me earlier, but I already have the perfect setup for doing DIS???? Electric water pump that I can space off the block however far I need to. A nice 1" thick chunk of aluminum that is my alternator belt tensioner mount sitting right next to the crank, and a JESEL belt drive with my camshaft spinning right there in plain sight.

[JeepsAndGuns]

Witch PCM specificly are you talking about? The 7427?
It will do batch fire, but wont do sequencial. It can also do DIS from what I read. Thats my next project after my mpfi.

[Six_Shooter]

DIS is just a few offset settings away.

Technically any of the common Delco ECM/PCM could control a DIS set-up.

[gregs78cam]

It will do batch fire, but wont do sequencial. It can also do DIS from what I read.
This I know...


It can also do DIS from what I read.

This I didn't. Thank you both for the clarification.

I was discussing using a '7727 I think, or whatever came in the '94-95 F, B, bodies.

[EagleMark]

I was discussing using a '7727 I think, or whatever came in the '94-95 F, B, bodies.16188051 and 16181333 $EE is what came in them. No chip, Flash through ALDL port PCM, SFI, Optispark Distributor. like my wrecked LT1 woody Wagon...

[RobertISaar]

hmm.... you could probably run DIS on it, but it might possibly be unnecessarily complicated.

i'm not too up to date on the PCM end of the 94-95 LT1 stuff, but if the high-res portion of the optispark can be tuned out, you could use a northstar-style crank trigger and ICM, that would generate the 4X signal the PCM uses for the main calculations.

not sure how well the LT1 PCM would like the lack of the 180X signal though...

otherwise, could used the optispark unit to grab reference signals (4X and 180X), then use the ignition control circuit of the PCM to trigger a northstar ICM that has a northstar style crank trigger to read(since it needs at least that to know which cylinders to fire).



but like i said, potentially complex.