Anyone ever tried DIY individual throttle bodies?

[Juiced]

ITB's Make it Very HArd to Tune a Car for Street Driving, the loss of manifold vaccum requires tons of fuel to be poured into the motor. If idle at cruising is no object then they are great and almost all GT and GTS and all P1 and P2 LeMans car Run some Sort OF ITB.

[pparaska]

(Opinion alert - I have no real experience with ITB, but some experience with tuning plenum type engines. Below is my understanding of some other ITB vs plenum issues. Of course, my understanding of this could be flawed. But I'm a pretty good student and look to get to the facts. Which is why much of what I believe in engine theory comes from what I read from David Vizard - someone with alot of theoretical technical insight, as well as someone who's been testing those theories on the dyno and race tracks for decades. Anyway, here goes : )

 

Interesting that no one has mentioned a few of the supposed advantages of ITB beyond throttle response: (1) improved midrange torque and (2) the ability to offset the uneven low end that at valve events with large overlap that a plenum design will exhibit.

 

These are related, of course. Overlap of valve events are useful in the exhaust (scavenging helping pull intake air or air/fuel into the chamber) but overlap almost always has a detrimental effect on at least some portions of the rpm range due to "stealing" of air or air/fuel from one cylinder to another. In some cases, the plenum can be made large enough that this may not be a big factor. In fact one way to look at an ITB setup is that the Earth's atmosphere is actually you plenum volume.

 

When you have no communication between cylinders in the intake tract, like with an ITB setup, there are much fewer problems with fuel standoff, lean versus rich cylinders, etc. This is due to each cylinder breathing off of the huge plenum of the atmosphere, each intake runner getting to start with the same initial conditions as any other when the intake valve or throttle plate opens more, etc. I'll quote Vizard on this ("How to Build Horspower, Volume 2," page 97):

As far as drivability and low end ooutput is concerned, especially when a larger cam is used, a system with a butterfly in each runner is preferable to open ports and a plenum situated butterfly. Unless a fuel injection system with port situated butterflies is used, the (ed- IR) carbs will outperform the fuel injection. The reason for this becomes apparent if we study what happens when a common set of butterflies controls the air for a number of cylinders. When the butterflies of a common plenum V8 system are closed, the manifold will be subjected to the vacuum drawn by the induction strokes of the pistons. When an intake valve opens, it will initially be in teh overlap phase, so the exhaust valve will also be open. Since all 8 cylinders are connected to a common plenum, on of the other cylinders will be at peak draw about half way through it's induction stroke. This cylinder will find it easier to draw the exhaust from whichever cylinder is in it's overlap phase, than it will to draw air through the closed butterflies of the plenum air valve (ed- he's referring to the throttle body or carb butterflies at the entrance to the plenum). This means that if low-end output and good manifold vacuum are required, the duration of the cam for a plenum type system must be kept shorter than for a system with port located butterflies (ed - IR system). The need for a shorter cam on such a setup, as for, say, a typical 350 CID V8 can cost as much as 50 horsepower. With a system having a butterfly located in each port, one cylinder cannot influence another. As a result of this the intake valve, in it's early opening phase, experiences far less vacuum than in the case of the common plenum. This allows the engine to use a much bigger cam before low speed drivability becomes unacceptable.

 

Vizard's writes later in the book (page 116):

With an IR system, the vacuum created in the runner, largely exists only when the piston starts it's downward stroke. Prior to this, there is, compared to a plenum type intake, almost no vacuum existing in the intake port during the overlap period. As a result, reduced exhaust pollution of the intake charge occurs from this source. This means that the idle mixture used, can be much leaner as the freshe charge is more easily ignited. Also, the ill effects a big cam (ed - read a lot of overlap) can have on part throttle operation at low RPM, are substatially reduced. It is not uncommon to achieve a smooth 600 rpm idle on a V8 equipped with a moderate race cam.

 

I realize that Vizard is talking about a V8 here, but that's because the book is about building SB Chevy V8's. There's no reason this is a V8-only phenomenon.

 

I plan to test this theory in practice - I'll be going from a plenum single plane intake with TBI injection to an old Hilborn mechanical fuel injection manifold with port EFI. Here's the Hilborn injector before:

[blaze73]

Great thread guys...i thought id chime in as, like vvillium3, i am also thinking of making my own intake manifold.

To answer a couple of your questions vvillium3, there have been a couple of centre TB manifolds out there, and ideally the air horn radius should be equal to the redius of the runner. As for the runner taper, length, and plenum size, those are all things i am still wondering about myself.

Phillip aka Blue, has just started an intake design forum on his clubs webpage and there is some great info over there already with lots of pics if anybody is interested. my name is ktzed over there, check it out.

http://www.atlanticz.ca/forum/viewforum.php?f=25

 

As most of this intake talk is geard towards N/A and i am doing a turbo swap, i was wondering what is required for an ideal turbo intake as compared to N/A. are certain things less/more crucial (runner length/taper, ITB vs single TB, plenum size) when designing a manifold for a turbo engine?

[Guest hegan1956]

Hi people, John put me onto this site after I asked about an idea a friend of mine talked to me about. So instead of retyping etc I'll just paste the original Question and let you all discuss it.

 

Hi lads and lasses,

 

I'm a new member on this site and after searching, I find no threads on L28 intake manifolds. I would like to do something with mine, but the lack of sources has left me frustrated. I have even talked with a buddy who thinks that he could build a tube style intake that gives a better airflow that OEM. What he came up with is tuned tubes like headers that would pull from 2 plenums with a balance tube and 2 TBs. He believe it would give it more lower rpm tourqe. He is basing it on an intake he built for a Dodge 225c.i. slant six he built to run modified production years ago. That was with 3-2bl. carbs on a 6" tube length, but he insist that the theory is the same. The way he explained it was the runners would be cut and the tubes tuned for the desired rpm. Has anyone out there tried anything like this or at least considered it?

 

Well here it is. As I understand the physics of airflow the shorter the intake the lower the rpm band. Also if you run individual runners a slick person could run short and long runners to extend the usable rpm band. Chevy did this back during the Can-Am wars with their big and small block configurations from Hilborn. I really like the short runner ITB setups, but I wonder if it would only give a very narrow powerband. Bike engines run at a much higher rpm than cars with a lot less mass. I guess thats one of the reason I liked the idea of a balance tube to help equalize out the airflow.

[Guest hegan1956]

John, I know this is about intakes, etc, but how do you have your water pump setup? The picture looks different than what I'm use to. It looks like a block off plate and piping. Do you have an electric pump system? That was another thing I was looking into.

[technicalninja]

I bet John's car had mind altering/passenger terrifying throttle responce. I believe that it would have been hard to measure the difference that a comparable ITB manifold would have made to his car. It would have increased the fabrication cost substaintially. Proper engine preparation and outfitting has a far greater effect on throttle response than intake design alone.

I also agree with Pete's comments and Vizard is one of my favorite authors for performance information.

Some of the ITB gains will be lost if the entry path to the system have to be worked into a street car application. (ie tight radius bends, air filters, etc)

Pete's manifold (if it is used as it sits) has phenomenal entrys- they are a bit obtrusive though. Wonder what the Police will think of them?

My experience with triple carbs set ups has shown a minor improvement at high end with a manifold design with totally seperate runners. The manifolds that had a connecting plenum between runners had a improved lower end, a better idle, were easier to tune and were less finicky about carb balance. For a street driven car some connection between runners is a definite plus. This feature might be less important in the case of F.I. as the manifold is not carrying an air/fuel mixture.

 

The fabricated plenum manifold would be easier to build and requires less precise machining. Many inexpensive TBs exist. Its not hard to set up a throttle cable system and balance will not be a problem. It will provide a much stronger vacuum signal at idle.

When a turbo is added to the system the ITBs therotical higher flow is no longer an issue. Total system obstrutions is the more important factor. 1 medium size throttle shaft and blade versus 6 smaller blades. The ITBs also create 6 times the leak potential and still have the throttle balance issues.

Reducing the throttle shaft obstruction is important enough that the latest BMW 8 cylinder engine has NO throttle blade (wide open intake-like a diesel) and uses intake valve manipulation to throttle the engine. This decrease in intake pumping losses was worth both power and fuel economy.

 

An easy way to fab up a ITB F.I. setup would be to take an old set of triples, Gut the carbs (sell the insides to defray costs) and mount injectors in the maniflod. only fab work would be injector mounts, fuel rails, and TPS.

 

I currently have a Mikuni triple manifold and 3 TWM 50 mm ITBs (2 injectors per barrel) for a turbo project engine. It would sure look neat but I will probably go for a hand built intake like John's for it's simplicity and fabrication ease.

Interesting thread- Hope it continues to grow.

 

Pete - where are the tennis balls? That intake requires tennis ball "covers"

 

Rick

[fl327]

ITBs are just frekin cool.

[johnc]

John, I know this is about intakes, etc, but how do you have your water pump setup? The picture looks different than what I'm use to. It looks like a block off plate and piping. Do you have an electric pump system? That was another thing I was looking into.

 

Nope, nothing that special. I ran a C&R double pass radiator and the outlets were on the driver's side of the radiator. I had it made that way on purpose so the oil heat exchanger was on the passenger side and the oil lines would be as short as possible. I had to fab a long aluminum tube for the bottom outlet to get it back over to the water pump inlet.

[johnc]

I bet John's car had mind altering/passenger terrifying throttle responce.

 

All as a result of a highly modified 35lb crank, low pressure valve springs, 2.5lb flyweel/flexplate, and a Quartermaster 5.5" OD double disk clutch. The intake was just along for the ride.

[pparaska]

Pete's manifold (if it is used as it sits) has phenomenal entrys- they are a bit obtrusive though. Wonder what the Police will think of them?

 

Well' date=' that's the setup as I bought it off of ebay. Obviously a race-only kind of setup . I bought some shorter stacks just like in this auction

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4544016801

(about 6" long) and plan to shorten them a bit as well as angle cut them on the bottom so they stick up at an angle so the will fit. This may not work well without a scoop of some kind. But in Vizards book, he shows some results of research on ram tube designs, including exponential flares like the ones in that auction, and lesser flares with 270degree rolled entrances (very important detail!), and then a very short eliptical shape that also flows as well as the longer flared ones. Not as much bling, but the FUNCTION.

 

I'd never put the long tubes through the hood, but I might use short ones under the hood. A buddy wants me to do that latter, and cut a hole in the hood and replace the steel removed with a clear plastic, like some of the old Ferarri's.

 

Pete - where are the tennis balls? That intake requires tennis ball "covers"

 

Yeah, those will be needed for the cruise ins and shows . Different colored ones, no doubt! Talk about old school bling! I guess I need fuzzy dice on the rear view mirror too! NOT!

[Guest iskone]

Nnja: 2 injectors. What are the locations distance from the back of the intake valve. Where you trying to pick up low end with the second injector?

 

Pete: What kind of engine are you building? for what porpouse?

 

 

I'm a Vizard student too (hard to tell when I can't even get a sprocket on)

I'm all for ITB's on a NA engine. In a boosted/blown engine they are not needed.

 

I think it would be possible to setup ITB's on a street ride and still have all the benefits of the ITB's Mid & high range, throtle reponse, larger cam (duration), intake pulse tuning.

 

I've been looking into a way I could do ITB's on my future engine. I'm seriously researching a 331 ford. I'm hoping for a lot by going with an ITB setup. I am trying to build an enigne that can turn to 7000 -7500rpm, killer throttle response, wide power band, and some streetablity along the same lines as my current setup. I'm trying to build a motor that will have it all, doable in a 2400# 240Z.

 

I havn't made to much progress with the ITB setup. I don't know how I'm gonna do it yet but it looks like I'll need a standalone for sure. I think if I use the stand alone to cotrol the fuel with o2 sensors it might work.

[pparaska]

Copied from my HybridZ Garage page:

 

"My SECOND V8 for the Z - 400 Chevy

* OK - so the 327 was fun! The cam (Comp Cams Xtreme XS274S-10) has a nice lope, breathes well from 2200-6400 rpm. But cruising in 5th at 65 mph is not very much fun. Bottom of the torque curve at cruise. Sure, I could have backed off on the cam duration/overlap, but then I'd have less power - and I have gotten used to the power as it is. The acceleration at the top end just isn't in the "scary" region where I want it.

* I did add a 700 cfm Holley Projection TBI setup to the engine, and now I can cruise even down at 1500 rpm, and it pulls much better from a 2000 rpm cruise.

* Oh, another problem developed. My ignorance, bad luck and some severely leaking (into the manifold) Holley carbs (into the manifold) caused the cylinders on the 327 to get fuel-washed. So now the 327 is an oil burner. A quart of 10W40 every 500 miles. After 4000 miles, it's a lost cause - worn rings and/or cylinder scuffing.

* So what does a gear head do? Get another engine! And of course, it has to be bigger and better than the last one! MORE POWER!!

* I've come to realize that how fast an engine revs has more to do with the torque it's putting out over the rpm band than the stroke of the engine. Sure, the 327 has a shorter stroke, so you'd think it'd rev quicker than a 400, but the 400 has a bunch more torque to accelerate the car. Plus it breathes better (larger bore). If you're happy with a 6300rpm redline (I am) then a 400 will do that - with a bunch more torque and power.

* Dave Williams at "Maximum Overdrive Racing Engines" had a 2 bolt 400 "509" casting (high nickel content) block that was standard bore. He took that and built a balanced and blueprinted shortblock that'll work out to 10.5:1 with 65 cc heads...

* Well, the old 461 casting "camel hump" heads just wouldn't do the 406 justice. So a set of 215cc intake runner Canfield heads were ordered... These are similar to the 220cc heads, but don't require offset rocker arms.

* Oh, that problem with washing down the cylinders with the Holley? Fixed with a good 650 DP carb. But that's going by the wayside since I bought a used 700 cfm Holley Pro-jection 4D throttle body injection kit. The 4D computer will be replaced with a Megasquirt computer in the future.

* The Specs: http://alteredz.com/EngineInfo.htm

- 2 Bolt 400 block, "509" high Nickel content", bored .030" over (4.155" bore), +.005" decked (pistons .005" above deck)

- Scat 9000 383, (6.0" rod) crank (PN 9-350-3750-6000), 3.750" Stroke x 6.000" x 2.100" Rod - Lightweight - Internal Balance, with 350-to-400 bearing spacers

- Probe Industries 15cc dished forged pistons (PN 1302-12341-030). Hastings 0.035" oversize rings custom gapped to 0.014".

- 5140 I beam 6" connecting rods, ARP bolts

- ARP main studs, head studs

- Canfield 215cc intake port, 65cc chamber Aluminum 23 degree heads (PN 23-550), 2.08/1.60 valves, Bowl ported (exhaust only)

- Comp Cams Pro Magnum 7/16" 1.52:1 ratio steel roller rockers. 7/16" screw in studs and guide plates. 0.040" Felpro 1014 head gaskets

- (Click here for quoted, out-of-box, and ported (exhaust) flow data) This combination gives about 10.5:1 compression ratio.

- Cam Motion PN 2442-2501-12-4 Solid Roller "Low Lash" Camshaft : 274/280 Advertised Duration, .577"/.570" lift (1.5:1), 244/251 @ 0.050" tappet lift, 112 degrees lobe separation, Isky Redzone lifters with pressurized roller oiling, Cloyes True Roller timing set, Scoggin-Dickey / Bo Laws 3 piece timing cover (PN SD60004)

- Edelbrock Victor Jr. PN 2975, single plane intake manifold

- Holley 700 cfm Pro-Jection 4D Throttle Body Fuel Injection (to be upgraded to a Megasquirt fuel injection computer).

- Recurved HEI distributor, HEI BruteThunder Coil, MSD Soft Touch Rev Limiter, MSD 8.5mm Super Conductor Plug Wires, Accel 734 plugs.

- Hooker Block Hugger Headers. Stainless Steel/Ceramic coated (along with most of the entire exhaust system ) (May go to full length tuned headers, 1-3/4" or 1-7/8" primary, 3" collector)

- Melling High Pressure SB pump, Canton Road Race oil pan and pickup, System 1 one quart filter.

- Based on the above data (assuming the long tube headers and mufflers), Desktop Dyno 2000 gives the following estimate: 535 lbft @ 4500 rpm 525 hp @ 5700 rpm. If I get 85% of that, I'll be more than satisfied!"

 

The use is 99% street cruising/ego-bruising, 0.5% Drags, 0.5% track days.

 

I want to move beyond TBI, plus the Holley 700cfm TBI I have will be too small for the 406 once I get that in.

 

I looked at the "packages" and their prices for port EFI - you know Holley, etc. $2500 for a single plane with injectors, air door, harness, sensors, ECU seems like too much to me. I found that I could get an old Hilborn on Ebay for ~$500 pretty easily (once I learned that everyone was using sniping software on these bids), and that putting in injector bungs, making fuel rails (or using fittings on the injectors and using braided hose and a distribution block), was not all that expensive. Then using Megasquirt and making your own harness, and buying som GM sensors and a Ford PWM idle solenoid would add maybe $500-$600 more.

 

So for less money, but more DIY work, I can have IR, which should make for a wider power band (use a lumpy cam for mid and top rpm range, but not hurt low end as much due to IR). That and be a bit diffferent than all the LT1, manifold and single carb, etc. setups that are so common.

 

I plan on making a 5 sided air box that includes a bottom that seals around the IR tubes, 4 vertical sides, all attached to the engine. Then have a flexible seal at the top of the 4 vertical sides that seals against the hood. Intake air to the box will be piped into the front or side vertical sides of the box, to the radiator support, with cone filters infront of the radiator support. That way I can pop the hood at a show and have the ram tube showing, except for tennis balls, or something else over them to keep the french fries, bugs, and small animals out of them . Also, I feel that many of the filters you see on the tubes probably screw up the flow characteristics of the ram tubes, and having a large plenum box that is fed by filtered air is better for performance.

 

The issue I see with doing the L6 with IR is that the brake booster gets in the way, as does the strut tower, but with the correct ram tube geometry, they can be much shorter and not be restrictive like a long, slightly flared tube.

[Guest iskone]

Pete, Have you thought about an ignition setup with out an HEI Dist.?

For Chevy's I've been looking into LS1 coil pack conversions but it gets damn pricey. For Fords I've been looking into the EDIS even EDIS on Chevy's has crossed my mind.

 

Any thoughts?

 

Isk

[pparaska]

Yes. I have a V2.2 Megasquirt computer (not running it yet) that I hope to hook to the Pro-Jection 4D harness in the car now, during this week.

 

I plan on going to MSnS-Extra to add EDIS later. I have a 36-1 tooth sprocket to mount on the crank, and all the EDIS-8 stuff from a 4.6L engine (bought from boostengineering.com for about $160 used).

 

After MS2 is released and the codebase moves toward the MSnS-Extra code, I may move to that.

 

Yeah, the HEI is going by the wayside. I'm REALLY tired of burned through rotors, irrepeatable mechanical advance, etc. The MSnS-E with EDIS will give me distributorless ignition cheap and fairly easy. Ford parts to run a Chevy Engine! What a mongrel!!! Yeah, whatever works - the parts don't know what engine they came from . Plus, that HEI won't fit with the Hilborn

[Guest iskone]

Sweet I'm glad to hear you've been thinking the same thing. So far your planning to do the exact same thing I intend to do when I start my Small block build (after the summer). For me I want to run the EDIS so I can move the SBC back further. I was thinking I'd go with a SBF but there is so little info on that swap but more importantly it would cost me more to get my 400hp in a ford. I mean when a Vortec SBC makes 400hp no prob cheap it really makes the Ford look bad. I think I'm scaling back my desired prm range too, just more reson to go SBC.

 

Are you going to upgrade the EDIS coil packs? I've read they can only do to about 6800. I know you won't go that high but you still may want a more reliable spark.

 

Keep us updated about your EDIS/SBC progress!!! Anything I learn I'll be glad to share but I hope you beat me to it so it's easier on me

 

Isk

[Tony D]

"Ford parts to run a Chevy Engine! What a mongrel!!!"

 

Wouldn't that be a Hybrid?

 

"There is not any room for purisim here!"

 

LOL

[randy 77zt]

i have a set of throttle bodies from a 2003 yamaha r1 1000cc sportbike.the reason they dont stumble is becuase there are vacuem operated slides in front of the throttle blades.kind of like an su with a injector behind it.throttle bores are 39mm.if i could find another set you could dissassemble them and make a row of 6.the map sensor has a vacuem line from all the cylinders.fuel rail is on bottem.

[tfreer85]

Okay I know its an old thread but I have some questions about this or another setup.

 

An easy way to fab up a ITB F.I. setup would be to take an old set of triples, Gut the carbs (sell the insides to defray costs) and mount injectors in the maniflod. only fab work would be injector mounts, fuel rails, and TPS.

 

I'm looking into dropping my E31 head on to my FI 78 L28 motor to have some fun with while I gather parts and money for my RB swap. Now with the prices of tripple carbs and TWM ITB's being upwards of 1200 plus, I kinda wanted to mess around with a cheap alternative preferably FI.

 

Now I was looking at the Motocycle 4 Throttle bodies that you can find on ebay for CHEAP and wondered if I would have to run 6 throttle bodies for this to work or if I could run say 2 runners off of the outer throttle bodies.

1 TB x 2 runners

1 TB x 1 runner

1 TB x 1 runner

1 TB x 2 runners in the order.

 

Now another option is get 2 Throttle bodies and run 3 runners from 1

throttle body.

1 TB x 3 Runners

1 TB x 3 Runners

 

However there is the option mentioned above I can get a set of Triple Carbs minus the Intake Manifold for $500 and then convert it to FI. Which option would be easiest, netting the most power? Or should I just buy the Carbs and find a manifold and run them. I just wanted to stay away from the original FI system. I plan on running Mega-Squirt to control everything. Thanks for any help or input.

 

Tyson

[PUSHER]

Wouldnt that defeat the point of ITBs? Also seems like youd have a tuning nightmare with the outer injectors and that they wouldnt be seeing as much air flow as the ones with 1 throttle body. If you can get them for cheap off ebay might as well get 2 sets of 4 and chop them up. If you got fab skills and tools that seems like the best route. For the carb triples where would you weld up the bungs for the injectors? If you do it in the stock location you could just get one of those 90$ fuel rails on ebay.

[tfreer85]

Yeah you have a point, that gets rid of using the set of 4 ITB setup. Any opinion on running 2 TB's with 3 runners? I'm really curious about converting the Triples to FI seems like it would require the least amount modification.

 

Tyson