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View Full Version : Sleeving my throttle bodies (lots of pictures)



sid pileski
03-19-2012, 12:25 PM
Many of you have seen my hotrod before:
http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/SIDSCAR-3.jpg

I have eight individule throttle bodies on the engine with EFI for fuel dlivery.

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/SIDSCAR-6.jpg

I think they look very good, fit the character of the car, and they work well after a long (for me) tuning process.
Thats where the issue starts. They work too well! The car is jumpy to drive.
Even with a progressive throttle pedal, when I hit the pedal it wants to jump.
A little background. This is a 514 engine in a 2500 or so pound car. Further, due to the fact that these are individule throttle bodies, one per cylinder, progressive throttles like a traditional four barrel is not possible. With a four barrel most times the "primary" two barrels feed the engine. Only when you really get into it do all four barrels come into play via a vacuum signal or a mechanical progressive linkage. I my case all of the trottle bodies open when the pedal is actuated.
By comparison, a standard "850" Holley carb has about 10,000 sq mm of surface area on the four butterflies. My setup has eight 50mm bores, equating to 15,000 sq mm of surface area.
Again, keep in mind the Holley only uses the primaries most of the time.

So, I thought about how I could tame this car a little. Lets face it, most of the time 99.99 I'm not out racing. This setup was origanally ment for racing applications. Thats what makes it look cool (again, my opinion). Smaller throttle bodies are not available from the manufacturer of these (TWM), and I didn't want to start over by making my own (maybe some day). So, I decided to sleeve these.

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/THROTTLEBODYTOPVIEW.jpg

I started by designing the sleeves, I did have the blanks made at work. I bought the material, they have the CNC lathe. Couple of hours later:

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/SLEEVES.jpg

sid pileski
03-19-2012, 12:31 PM
Next, I drilled the blanks for the butterfly shafts. That was pretty straight forward. The real challange was the injector pockets at a 30 deg angle from the center axis:

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/THROTTLEBODYANDINJECTORPOCKETS.jpg

So I made a fixture to hold the sleeve to bore the pocket:

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/MAKINGINJECTORFIXTURE.jpg

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/FIXTUREANDSLEEVE.jpg
http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/SLEEVEINFIXTURE.jpg

ahidley
03-19-2012, 12:33 PM
iF IT were me. I would make the gas pedal travel farther, via linkage. Not progressive, just move farther.

sid pileski
03-19-2012, 12:37 PM
Next I marked out where the holes should be:

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/MARKINGINJECTORPOCKET.jpg

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/ALIGNINGINJECTORPOCKET.jpg

Boring the pockests:

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/BORINGINJECTORPOCKET.jpg

Done:

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/BOREDINJECTORPOCKET.jpg

sid pileski
03-19-2012, 12:40 PM
The last thing to do was make the new butterflies. I made a fixture to turn these at a 14 deg angle, because that is what they shut off on the inner bore.

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/BLADEFIXTURE.jpg

This imparts the correct angle on the part.

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/36AND50MMBLADES.jpg

The finished product:

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/SLEEVESINSTALLED.jpg

The electronics will have to be retuned, but that should not be that bad to do now that its been done before.
This should make things a little more driveable.
If not, all can be return to the way it was. Thats the beauty of doing it this way.

Sid

EVguru
03-19-2012, 12:57 PM
Does your ECU run Alpha-N or Speed-density?

The earlier Ducati Monsters used Alpha-N and had a poor reputation for ridability (a collegue at work sold his because he couldn't trust it on leaf strewn roads). They used a non linear throttle pot to help smooth things out, but most dealers weren't capable of setting them up right. Swapping the ECU out for one that ran Speed-density solved the problem. They already had a MAP sensor fitted, but only used it for altitude compensation at power-up.

Joe Rogers
03-19-2012, 01:01 PM
Nicely done! I will be interested to see how the tuning and throttle response turns out. Is the drive line manual or automatic? If it is auto a much higher stall speed converter may have served to tame the beast.
Joe

millwrong
03-19-2012, 01:25 PM
You have an amazing car, that is a testament to your skills, and ingenuity! I'm thrilled every time you show it! Thanks!

sid pileski
03-19-2012, 01:26 PM
The TPS is linear. The ECU is from Electromotive. It is a very capable controller (read complicated). But will do a lot of things.

The tranny is a five speed Richmond. Real hotrods have three pedals!

Sid

EddyCurr
03-19-2012, 02:56 PM
Nicely done and a great pictorial.

I enjoyed seeing details of the various fixtures used to perform
the modifications. Some thought and preparation went into
those.

.

sid pileski
03-19-2012, 04:13 PM
Eddy-

Thanks! I have everything layed out in cad, as I do with most things. Saves a lot of mistakes and time IMO. A lot easier to make mistakes and changes dealing with electrons vs. aluminum!

bob_s
03-19-2012, 04:14 PM
Instead of sleeving the throttle bodies, could you not have made a compound butterfly? Would behave in similar fashion to conventional four barrel carburetor.

sid pileski
03-19-2012, 04:25 PM
Bob- What do you mean a compound butterfly?

DICKEYBIRD
03-19-2012, 04:31 PM
Awesome post & pics of your very tidy workmanship and design work, thanks!:)

No fair draping towels everywhere to hide the rest of your shop though.:p

sid pileski
03-19-2012, 04:48 PM
Dickey, I just add the towel for a non-distracting background.
My shop is equally clean and organized. I'm a bit of a neat freak.

http://img.photobucket.com/albums/v108/sids32/Image008.jpg
http://img.photobucket.com/albums/v108/sids32/Image174.jpg

QSIMDO
03-19-2012, 05:44 PM
NASCAR restrictor plates?

Absolutely beautiful car BTW.

sasquatch
03-19-2012, 06:23 PM
Sid, great rod, and want to thank you for posting these very interesting pics!!

Hope the summer produces some great rides and cruises for ya!!

A.K. Boomer
03-19-2012, 06:32 PM
Boy Sid u really do go through the pains,,, hope it turns out good, was wondering about progressive actuators on the throttle body's themselves along with your pedal would have made some diff.

They need to have a new TV show called "machine shop swap"

it's kinda like wife swap except two guys swap out very "different" shops and try to work on stuff there --- U and Sir john could kick off the season and neither of u would find anything - would be fun to watch SJ cussing up a storm:p and u spend the first week cleaning. lol

sid pileski
03-19-2012, 06:50 PM
Well, here's the thing. With eight barrels opening at the same time, even a small crack of the eight of them is like opening up a single, say 80mm throttle body, a lot. What would that feel like in a new Mustang or Camaro (choose your brand)?

Anyway, I think I could work with John. The difference is, while my shop is a money making endeavor, I have a 8hr+ day job (engineer). I would guess that John's shop is a full time shop. If your cleaning, your not making money.

Maybe we could teach each other a few things!

Sid

Forestgnome
03-19-2012, 06:58 PM
Actually your cfm math is a little off. With a carb, depending on whether you're running a dual or single plane manifold, each cylinder "sees" 50% or 100% of the available bore area. Running one bore per cylinder as in your setup each cylinder sees considerably less intake area. That might be why you have such good throttle response. WOT would be suffer vs. a carb. You could be exacerbating the problem by decreasing the bore. Beautiful rod by the way!

Black_Moons
03-19-2012, 07:23 PM
I guess it does not matter much since you would have to be crazy to go WOT in something that awesome, But it seems like a shame to do a modification to decrease overall performance just to lower the performance just off the idle pedal position.

My truck has a similar problem.. I have seen it accelerate to 45kph just idling on a cold day before the engine warmed up (automatic, accelerates until it shifts into 3rd gear just idling on flat road), And just touching the gas pedal is the difference between a quiet idle and a roaring motor that is catching up on whatever car is in front of me.. I honestly only use the first 10% of travel even when accelerating, Maybe the next 20% if I am doing a merge on a fast highway. WOT is... Just scary.

Seems to me that the correct solution would be to alter the throttle linkages to be less linear, Such that we actually use the first half or so of the pedal travel during daily driving, as opposed to the 10% or so we are using now.

sid pileski
03-19-2012, 08:29 PM
This is something I made last year to also help the drivability of this car. I call it a balancing manifold:

http://img.photobucket.com/albums/v108/sids32/BALANCER%20CONSTRUCTION/BALANCER23.jpg
http://img.photobucket.com/albums/v108/sids32/BALANCER%20CONSTRUCTION/BALANCER20.jpg
http://img.photobucket.com/albums/v108/sids32/BALANCER%20CONSTRUCTION/BALANCER17.jpg

It is placed between the throttle bodies and the intake manifold. It helped the drivability a LOT. This also made the balancing of the TB to each other a mute point.
There is a reason you don't see this type of setup on the street much, and you do see them on the track where just off idle is not that big a deal.
I think this in conjunction with the sleeved TB will be another step in the right direction.

jkilroy
03-19-2012, 08:32 PM
I am afraid that taking the bore down smaller is going to increase bottom end response and make the car even more "jumpy". First thing I would do is modify your spark advance and take a bunch of initial advance out, say cut it by 4 degrees and go from there. After that I would enrich the injector pulse right off idle, this will soften it a bit more but sure won't help *mileage* (lol I know)

If you want to stick to metal working projects work out a progressive linkage that would slow down throttle movement at off idle a lot, up to about 20% open, after that it doesn't matter, might as well be WOT by then. I am sure that car would get you thrown in jail way before 20% throttle.

justanengineer
03-19-2012, 09:10 PM
Nice clean work, and beautiful ride, but I would handle things a bit differently.

I would start by dialing down the fuel pressure regulator (assuming you have one), and consider switching to a smaller injector, as both tend to be oversized in "racing" applications. I would also then go do a bit of re-mapping, as once again "racing" applications tend to be heavily on the rich side of stoich. Lean it out a bit, back off the spark a bit, and I think you will have a nice cruising street car.

I also dont see why you couldnt simply stagger the throttle bodies, but I dont wanna start an argument in a gloat/project thread.

Hope to see you at the Syracuse Nats this year. Nice ride.

sid pileski
03-19-2012, 09:11 PM
Look at the first photo of the balancer. The black anodized pulley in the middle is going to become an eccentric one. That will also help the cause.

Another thing in the plan. If I have to open the bores more, I can down the road. Unfortunately, I don't have a dyno, so testing is seat up the pants and theory.
I've talked with a few throttle body manufacturers, when I explained what I had in mind to one about the sleeving he wanted to record the conversation.
He said everybody always wants the biggest TB they can get. He was pleased to hear what I was doing.
So, we still have a few months up here in the north east before I can get the car back out, and I'm doing some other modifications to it also.

The proof will be in the drive.

sid pileski
03-19-2012, 09:23 PM
Engineer- I've been there every year from the start. They are in my backyard. (Syracuse Nationals).

Do you bring a car?

The staggered TB thing is not really an option. Even with the balancing manifold I think there would be an imbalance between cylinders.
Keep in mind that these are siamese TBs. They are a 4 x 2 configuration.

murph64
03-19-2012, 09:34 PM
The tranny is a five speed Richmond. Real hotrods have three pedals!

Sid


And the congrgation says amen ...The congregation also says "holy sch!tt that's a nice car!" :D

BTW I was up in your neck of the woods two or three years ago, the wife had a week long conference at Welch Allyn.

Andy

sid pileski
03-19-2012, 09:39 PM
Well Murph what a coincidence, that's where I work.
Was she at the "Lodge"?

Thanks- Sid

justanengineer
03-19-2012, 10:23 PM
Ive been to the Nats every year since 2007, and went to one of the early ones (2000 or 01 maybe?). Im rather amazed at how it seems to keep growing, even given the economy. Honestly, Ive never had an old enough car I felt was worth entering in a show with that large of an attendance. Shows like that are better left to classic rides like yours, and while I would love to (and will one day) build a 20s or early 30s roadster, Ive never had the money, I cant stand rusty rat rods (other than the guy w/the International pickup sporting the Farmall grill), and newer vehicles like my 99 Firebird seem out of place (outside of the many local cruise nights). I never fail to find a friend or relative to ride in with tho... :)

Thinking about it a bit more, the way your intake is laid out it would be more of a pain than anything to stagger the throttle bodies and probably not covered in ECU tuning software. You would need to stagger every other cylinder, front+back in, center out, or some other such nonsense, and there are too many other ways to settle it down. Where do you take air measurements at in this system btw? Just curious if you have a MAF in each TB, or another setup. Being that you have an aftermarket ECU, the possiblities are almost endless, but the PITA tuning factor increases exponentially for each I/O added.

Think Imma go make a sign to hang on my Firebird, "Will trade for early hot rod."

EVguru
03-20-2012, 05:53 AM
The TPS is linear. The ECU is from Electromotive. It is a very capable controller (read complicated). But will do a lot of things.
It doesn't look like you're running a MAP sensor, which means you're running Alpha-N. That uses throttle angle and rpm to determine the fuel map. Like with the Ducati Monster, that's going to be a significant part of your problem.

The problem for street use is that at small throttle openings, very small changes in butterfly angle mean large changes in air flow. You need very good resolution on the throttle angle sensor and in an application like yours no flex in the actuating mechanism leading to delays between some butterflies and others.

Speed-density in contrast uses Manifold Absolute Pressure (MAP) which changes a lot with butterfly angle at small throttle opening. This is much better for street use.

MAP doesn't change much at larger throttle openings, so Alpha-N is better there which is why it's usually used in racing applications. Some ECUs can swap between the algorithms with the flick of a switch and some can even blend from one to the other giving you the best of both methods.

Doozer
03-20-2012, 07:58 AM
1. Retard the heck out of the ignition timing at idle, have it get into advance with a 2 or 3 second delay after opening the throttle.
2. Try drive by wire. I like the pedal conneceted to the butterflys too, but by wire would solve your problem.

--Doozer

sid pileski
03-20-2012, 08:25 AM
This system uses a MAP sensor. I have it set up for batch fire too.
But with the addition of a cam sensor it can do sequential fire.

Sid

A.K. Boomer
03-20-2012, 10:26 AM
2. Try drive by wire. I like the pedal conneceted to the butterflys too, but by wire would solve your problem.

--Doozer

It would not solve anything -
He doesn't have direct injection - its conventional multi-port, he still needs the butterflies or some kinda means to shut the air flow down and open it back up...

Doozer
03-20-2012, 10:36 AM
Drive by wire has a servo motor that moves the butterflys for you.
The gas pedal is only a potentiometer that gives electrical input.

-Doozer

EVguru
03-20-2012, 10:40 AM
It would not solve anything -
He doesn't have direct injection - its conventional multi-port, he still needs the butterflies or some kinda means to shut the air flow down and open it back up...

Sensor on pedal.

Servo on butterflies.

Algorithm maps pedal position to servo to give torque control, or speed control, or whatever is desired.

F1 and Moto GP both used that system until banned.

sid pileski
03-20-2012, 11:01 AM
Well- Drive by wire is now coming into the hotrod world. I just saw an article about an after market pedal assy being offered. Opening one TB with it's spring return is one thing. Opening up eight of these might be another?
Does the servo both open and close or do they rely on return spring(s)?
How much torque can they provide?
I'm probably not looking to make that type of change right now anyway. But, who knows in the future? Thats the nature of this hobby. At leaset for me.
Every year I usually make some change or improvment.

Sid

A.K. Boomer
03-20-2012, 11:23 AM
Drive by wire has a servo motor that moves the butterflys for you.
The gas pedal is only a potentiometer that gives electrical input.

-Doozer


And your still going to have to deal with "ratio" control --- so why not just take care of it mechanically.

Like on my old 62.5 mpg tercel, Nip it in the bud mechanically - it's right in front of your face, -------- before;

http://i146.photobucket.com/albums/r249/AK_Boomer/DSC00377.jpg

After;

http://i146.photobucket.com/albums/r249/AK_Boomer/DSC00388.jpg


still not enough? then build a custom throttle pedal and you can change the ratios 4 fold off the start and still get full throttle when u really tromp down on it - and it turns out to be a beautiful thing with the throttle spring resistance also --- very light for fine tuning off the start and if you do want full throttle you have to apply allot of pressure, perfect....

Note; With Sids talents he could build a custom set up for almost nothing at all -- and what do u think a drive by wire conversion would cost --- and one that would work properly for his "unique" multi- TB's? (that's if they even make a potentiometer pedal with that kind of a ramp scale, if not then you backed yourself into a corner and your hands are tied) it would be through the roof and not as cool...

Doozer
03-20-2012, 11:30 AM
A mechanical progressive linkage was mentioned early on in the thread. I was posing drive by wire as a new and alternative idea.
I like you setup though. A 62 mpg Yoda is very cool. Much the rason the new 50 mpg hybrids do not impress me.
--Doozer

A.K. Boomer
03-20-2012, 11:49 AM
It's all simple leverage ratio's, he may have screwed the pooch a little with his initial 14 degree butterfly angle - a lesser angle to start with would have totally mellowed things out - but that just means he needs to change the ratio elsewhere --- and he could do it very refined - not like in my crude (but effective) ratio change. if he want's to get beautifully radical he could go eccentric gear to gear for starters...

Doozer
03-20-2012, 12:01 PM
"- a lesser angle to start with would have totally mellowed things out - "

Had not thought of that. Great idea and easy to remake the throttle plates.
I once made 12 buttrerflys using the eliptical wobble method in the lathe for a friend with a V6 Mercury Cogar. Some drive by wire intermediate manifold runner control (IMRC) that went from short intake runners for high rpm to long intake runners for low rpm. I bored out the 12 throttle bodies on the Bridgeport and made new butterflies on the lathe. I used 12 degrees, only because what is what they were origionally.

Yes, I would try flatter (less eliptical) throttle butterflys.

--Doozer

sid pileski
03-20-2012, 12:02 PM
AK- The need for the 14 deg is so you have a reasonable shutoff surface and so that they don't stick in the bores. The 14 deg angle I ripped off directly from Kinsler. They offer a variety of butterflies of various diameters.

Sid

A.K. Boomer
03-20-2012, 01:02 PM
I once made 12 buttrerflys using the eliptical wobble method in the lathe for a friend with a V6 Mercury Cogar. Some drive by wire intermediate manifold runner control (IMRC) that went from short intake runners for high rpm to long intake runners for low rpm. I bored out the 12 throttle bodies on the Bridgeport and made new butterflies on the lathe. I used 12 degrees, only because what is what they were origionally.

--Doozer


Very cool and very involved --- u are more familiar with DBW than I as iv never heard of such a system...

A.K. Boomer
03-20-2012, 01:06 PM
AK- The need for the 14 deg is so you have a reasonable shutoff surface and so that they don't stick in the bores. The 14 deg angle I ripped off directly from Kinsler. They offer a variety of butterflies of various diameters.

Sid


I can understand that Sid to some "degree" - but that's why they make adjustable stops --- I wonder what the minimum that u can get away with without being "sticky" is??? (say on something like a 50mm bore)

murph64
03-20-2012, 02:03 PM
Well Murph what a coincidence, that's where I work.
Was she at the "Lodge"?

Thanks- Sid


Yup.. REAL swanky. The conference was for NYS school nurses, a LOT different than they are used to :) I had the kids (5 and 3) out on the deck looking for fish in the pond for hours...



Andy

Peter.
03-20-2012, 02:14 PM
Sid if your ECU is capable you might want to try running speed-density up to about 10-12% throttle then alpha-n from then up. This should help your lurching issues a lot. Many motorbikes use this method, as you can imagine you don't need low-throttle lurches on a leaned-over sportsbike.

A.K. Boomer
03-20-2012, 04:39 PM
there's so many ways to skin this catfish I do find it interesting - from progressive linkage and roller cams to even hydraulic --- imagine having a two stage hydraulic throttle to show off, very safe - if it does ever get air it leans to the side of no response - internal springing at the two stage master (piston inside of a piston) and external at the slave, whats not to luv?

imagine all the gawkers at the car show where im sure Sid already gets his fair share finding out about the car with the two stage hydraulic throttle:)

sid pileski
03-20-2012, 08:48 PM
I've been working with this set up for a while to get it perfected. If it was a single TB it would be pretty much plug and play. Everyone dose that now.
Kind of like putting a small block chevy in a hot rod (Oh boy, I stepped in it now!!) Really, to each his own. Anyway, I like that it looks different and if it takes some time to get it perfect, that's OK. All part of the fun!
Look at the attached screen shot. The pulley in the middle is next to be modified. I'm going to design and make a progressive pulley for this. Some have you have suggested this (honestly it was on the list anyway!).

http://img.photobucket.com/albums/v108/sids32/THROTTLE%20BODYS/3-20-20125-21-34PM.jpg

scooterman
03-20-2012, 09:36 PM
Sid, nice ride and great workmanship,if I may, in years past (1960's, moving forward) and having used forced induction systems and direct port (mechanical fuel injection systems) on hot rods, drag cars, the key to usual success was the absolute timing of the fuel/to air ratio, which was usually the fuel pressure(sleeve metering, port timing, etc) being in time with the butterfly going open. On the mechanical side, camshaft duration and overlap would play a very important phase in performance. Not knowing what you are are using in the way of camshaft selection and its performance to "feed" the cylinders, perhaps by sleeving down the throttle bodies you have created a negative AFR which I think would account for a tamer throttle response, until you firewall the loud pedal and there would be a "stall" or lag. With individual port delivery, with out a penulem effect such as a manifold the induction system,MAS,FRC, tunning gets pretty difficult,, just a thought, then again, thats why we build stuff!