Modified throttle bodies survey/thoughts
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Modified throttle bodies survey/thoughts
I am thinking of offering a service to enlarge throttle bodies by 2mm including new flappers which would allow for more aire flow. cost should be in the $125-$140 range plus return shipping. Thoughts?? Brucey please chime in.
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
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Re: Modified throttle bodies survey/thoughts
I would be interested in knowing if this either makes for a meaningful increase in power by itself, or is more of an 'enabler' so that you get more value out of other tuning changes. Everything makes a difference of course (all the flow resistances adds up) but the single biggest restriction is the valve time/lift of the standard camshafts. With a revised camshaft very healthy gains in power are possible, even without other changes, albeit that they come with less low rpm torque too.
I suspect that the TB being the size it is was originally because without at least a slight choke to the flow, there wouldn't be a good vacuum signal (esp near WOT) to control the ignition timing when using a distributor with vacuum advance.
IIRC the casting is pretty thin walled; I'm not sure if there is a real danger of breaking through or not. But overall it is one of those things that could do some good and (with the possible exception of breaking through the casting) oughtn't do any harm.
cheers
I suspect that the TB being the size it is was originally because without at least a slight choke to the flow, there wouldn't be a good vacuum signal (esp near WOT) to control the ignition timing when using a distributor with vacuum advance.
IIRC the casting is pretty thin walled; I'm not sure if there is a real danger of breaking through or not. But overall it is one of those things that could do some good and (with the possible exception of breaking through the casting) oughtn't do any harm.
cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Re: Modified throttle bodies survey/thoughts
"Jordanmilos" used to modify TBs. Lots of info. if you do a search.
I think he bored it out by around 4mm. I had one on MILI before I sold it. Can't find the pic now.
I think he bored it out by around 4mm. I had one on MILI before I sold it. Can't find the pic now.
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Re: Modified throttle bodies survey/thoughts
I have one of Jordan Milos' TB's on my car now, which hasn't been fired yet. I believe he was only taking them out 2MM but when I get over to where the car is I can throw a caliper on it and compare it to a stock unit. Jordan was also charging $250 per.
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
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Re: Modified throttle bodies survey/thoughts
This comment from the E9 forum..."Had a modified one on a Porsche, also on the 3.5 that was originally in my e9. Both improved responsiveness."
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
flickr.com/photos/bertsphotos.
Re: Modified throttle bodies survey/thoughts
Bert, I might be interested in that, also have a few extra, early throttle bodies if you need some to play around with!
Klaus
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Re: Modified throttle bodies survey/thoughts
Hi Klaus,Been a while. When I go to my machinist in a week or so to pick up my spin on oil filter adapters, I will bring him an extra Motronic body I have and we can measure it up and figure out what we can take out of it. He has been doing this to corvette TB's so knows what he is doing. Anyway, once we figure it out I will post up some more info. I bought mine years ago from another fellow that was doing them, but he was charging $250 for the same thing.Go figure!! Anyway, I will keep everyone in the loop
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
flickr.com/photos/bertsphotos.
Re: Modified throttle bodies survey/thoughts
I would have thought that the highest airflow restriction would be at the Air Flow Meter not at the Throttle Body.
Dave
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Re: Modified throttle bodies survey/thoughts
Read the comment from an E9 member 3 posts up
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Re: Modified throttle bodies survey/thoughts
Would taking off that extra 2/4mm apply to only late model TB or would this also apply to early models too?
Anyone have pictures of this? or a link?
Anyone have pictures of this? or a link?
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Re: Modified throttle bodies survey/thoughts
It will only be 2mm. First one is at the machinist being done at his liesure. We decided going any bigger is pushing it.that is on a Motronic TB
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.
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Re: Modified throttle bodies survey/thoughts
I don't recall ever charging $250 for a throttle body. Even the ones that I powder coated and upgraded the linkage on, I think the most I ever got for one was $200. Stock throttles were in the $165 range with shipping included and no core. There is a good amount of work to get a throttle to seal properly, which includes machining the throttle body while following the original bore as it was machined from the DVG factory.
2mm is not anywhere near the limit of the throttle body if you set up the axial runout properly.
2mm is not anywhere near the limit of the throttle body if you set up the axial runout properly.
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Re: Modified throttle bodies survey/thoughts
Jordan This seems to be turning into a pissing contest of some sort. i got my throttle body from you somewhere around 8 years ago . We exchanged parts for them and the value on the parts I traded to you, if I was to sell them, they were parts I was producing them at the time, was $250 as that is what I would have sold them for. Now maybe you figured them at a lesser value as the price you put on your throttle bodies was a lesser value so each one of us had a different idea of value at that point. Surely not something to debate when you take that into consideration. Usually in any kind of a trade each person has a different idea of value on their side. Same as in a car deal!
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
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Re: Modified throttle bodies survey/thoughts
It seems that every time you chine in on something having to do with my transactions, your facts are skewed to make yourself look like whatever it is you feel you need to look like.
Post by bpoliakoff » Wed Jul 16, 2014 4:50 pm
Rubber not available separately. Years ago, I was having identical,die extruded rubber to match the originals. I ran out of them and never had more made. I was the only source doing this world wide.
I have to order them in quantities of 10 sets. So if 10 guys step up, I will do them for $150 a pair providing the fellow who made the dies for me still has the dies and and extrusion machinery and is still "kicking"
I gave factual info on the bore size and expalined to anyone who was willing to read and get that information, that the inflated value of what you claimed I charged was simply false.
Post by bpoliakoff » Wed Jul 16, 2014 4:50 pm
Rubber not available separately. Years ago, I was having identical,die extruded rubber to match the originals. I ran out of them and never had more made. I was the only source doing this world wide.
I have to order them in quantities of 10 sets. So if 10 guys step up, I will do them for $150 a pair providing the fellow who made the dies for me still has the dies and and extrusion machinery and is still "kicking"
I gave factual info on the bore size and expalined to anyone who was willing to read and get that information, that the inflated value of what you claimed I charged was simply false.
Last edited by Jordanmilos on Mon Jan 21, 2019 1:24 pm, edited 1 time in total.
Big Bore Throttle Bodies, Gauge Kits, and more.... No more actually.
Re: Modified throttle bodies survey/thoughts
I would like to chime in regarding the increase in bore. Since I am on a path of increasing flow to the head I have done some research regarding boring. I would first concentrate on Throttle body Bore size as a velocity is vital in atomization. There is research and Real world results that show that converting a throttle body to a shafless unit will increase flow by up to 12 percent when you get rid of the "hump" in the butterfly. It's more complex to convert BUT as I am working on this now I may be able to help later with input.
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Re: Modified throttle bodies survey/thoughts
With this being said I would be interested in being apart of the group of 10.Jordanmilos wrote: ↑Sun Jan 20, 2019 2:20 am It seems that every time you chine in on something having to do with my transactions, your facts are skewed to make yourself look like whatever it is you feel you need to look like.
Post by bpoliakoff » Wed Jul 16, 2014 4:50 pm
Rubber not available separately. Years ago, I was having identical,die extruded rubber to match the originals. I ran out of them and never had more made. I was the only source doing this world wide.
I have to order them in quantities of 10 sets. So if 10 guys step up, I will do them for $150 a pair providing the fellow who made the dies for me still has the dies and and extrusion machinery and is still "kicking"
I gave factual info on the bore size and expalined to anyone who was willing to read and get that information, that the inflated value of what you claimed I charged was simply false.
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Re: Modified throttle bodies survey/thoughts
TBM, I not only agree but I also value your input on the subject of removing the shaft hump from the scenario of obstructing volumetric flow. Have you tried this setup on your car yet? Anything noticeable?TBM wrote: ↑Sun Jan 20, 2019 2:59 am I would like to chime in regarding the increase in bore. Since I am on a path of increasing flow to the head I have done some research regarding boring. I would first concentrate on Throttle body Bore size as a velocity is vital in atomization. There is research and Real world results that show that converting a throttle body to a shafless unit will increase flow by up to 12 percent when you get rid of the "hump" in the butterfly. It's more complex to convert BUT as I am working on this now I may be able to help later with input.
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Re: Modified throttle bodies survey/thoughts
I'm in the process of setting it up. My results will be hard to quantify unless I run back to back with Original ITB's when we flow the head.. I will try but not sure if I will have the chance.Kurtamine_ wrote: ↑Fri Jan 25, 2019 12:23 amTBM, I not only agree but I also value your input on the subject of removing the shaft hump from the scenario of obstructing volumetric flow. Have you tried this setup on your car yet? Anything noticeable?TBM wrote: ↑Sun Jan 20, 2019 2:59 am I would like to chime in regarding the increase in bore. Since I am on a path of increasing flow to the head I have done some research regarding boring. I would first concentrate on Throttle body Bore size as a velocity is vital in atomization. There is research and Real world results that show that converting a throttle body to a shafless unit will increase flow by up to 12 percent when you get rid of the "hump" in the butterfly. It's more complex to convert BUT as I am working on this now I may be able to help later with input.
AT-Power .jpg
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Re: Modified throttle bodies survey/thoughts
Just curious why everyone wants to stick with the OEM TB?? There are plenty of generic, Honda and mustang throttle bodies out there for 50-150$ all day long new and used. These range from 65-105mm depending on the application. All you need is a simple four bolt adapter made from 1” aluminum plate. Pretty easy to make even on a manual machine. The mustang 5.0L BBK 70mm unit I got for 75 on eBay even has the idle air control and TPS.
A little research and the plug on the mustang IAC is the same as the motoronic one. The tps would require some fab to use the stock one but I’m going to be running Megasquirt.
I suspect that anyone needing a larger TB to this magnitude won’t have issues with these minor fabrication tasks.
A little research and the plug on the mustang IAC is the same as the motoronic one. The tps would require some fab to use the stock one but I’m going to be running Megasquirt.
I suspect that anyone needing a larger TB to this magnitude won’t have issues with these minor fabrication tasks.
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Re: Modified throttle bodies survey/thoughts
It comes down to a matter of cost. You’ll be likely to spend twice as much getting a different throttle body on the car, and then you have to open the manifold to match any higher bores.
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Re: Modified throttle bodies survey/thoughts
I'd be very interested to hear how your installation works out!TBM wrote: ↑Sun Jan 20, 2019 2:59 am I would like to chime in regarding the increase in bore. Since I am on a path of increasing flow to the head I have done some research regarding boring. I would first concentrate on Throttle body Bore size as a velocity is vital in atomization. There is research and Real world results that show that converting a throttle body to a shafless unit will increase flow by up to 12 percent when you get rid of the "hump" in the butterfly. It's more complex to convert BUT as I am working on this now I may be able to help later with input.