Alternative throttle bodies?
#1
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Alternative throttle bodies?
Has anyone used a throttle body other than the 13b one? I want to find a way to make like a big 65mm or larger work with the 13b. It's for a new intake manifold design I'm working on.
#2
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I've seen people use independent TBs for NAs. I always thought it'd be cool to run a dull turbo/dull intake system. Make each rotor with it's own turbo, intake, and TB. Of course, this would require a lot of plumbing and i don't if it'd fit in the car.
#4
...94% correct.
Thread Starter
Iwant to use something like this:
http://cgi.ebay.com/ebaymotors/ws/eB...category=33558
I'm wanting to do this for TII's. I'm wanting to make a dual "Y" manifold that will wrap over the top of the engine and face the TB towards the front of the car...kinna toward the battery area (easy lumbing for FMIC). It'll have longer, equal length runners and no plenum. I've been wanting to do something like this for a long time.
The TPS is the only problem I can really think of, but it's just activated by the degree at which the buterflies are open. On an axis, no matter how big, 20* is 20*...so I think that I might be able to find a way to mount the stock TPS to it and use that.
http://cgi.ebay.com/ebaymotors/ws/eB...category=33558
I'm wanting to do this for TII's. I'm wanting to make a dual "Y" manifold that will wrap over the top of the engine and face the TB towards the front of the car...kinna toward the battery area (easy lumbing for FMIC). It'll have longer, equal length runners and no plenum. I've been wanting to do something like this for a long time.
The TPS is the only problem I can really think of, but it's just activated by the degree at which the buterflies are open. On an axis, no matter how big, 20* is 20*...so I think that I might be able to find a way to mount the stock TPS to it and use that.
Last edited by Makenzie71; 10-13-04 at 03:34 PM.
#5
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You probably could, or you could go after market ECU and aftermarket TPS. Do you think that TB would be bigger then the 3 ports in the stock TB though?
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#8
If I remember correctly from another thread, people found that going to a single large throttle plate caused insanely touchy low throttle behavior, making around-town driving nearly impossible. Something to consider.
-=Russ=-
-=Russ=-
#10
...94% correct.
Thread Starter
Originally Posted by Mint87RX7
i think our tb is like 90mm anyway, my freinds eclipse has like a 62 and it fits inside mine
The 13b actually has three throttle bodies...30mm a piece. My calculations above are correct. Our 3 throttles have about the same flow as a single 52mm body.
I've never seen a 13b with a single-butterfly tb. Pics or links to people with problems? I can't imagine someone having a problem unless they didn't do it right.
#11
...94% correct.
Thread Starter
Found the perfect donor: MKIII Supra 60mm throttle. It's an easy design to work with and, if need is there, it's easy to find a larger body that will bolt up to a flange made for it.
#12
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Originally Posted by Makenzie71
The 13b actually has three throttle bodies...30mm a piece. My calculations above are correct. Our 3 throttles have about the same flow as a single 52mm body.
I can't imagine someone having a problem unless they didn't do it right.
Last edited by NZConvertible; 10-14-04 at 12:20 AM.
#13
...94% correct.
Thread Starter
Oh....I guess I'll have to find a larger TB then. I thought the ports were only 30mm a piece...picked it from some random thread. And I'm not trying to find a larger one, really...just an adequate one that'll be easy to work with.
Everything that you do for a gain in one area, will be at the sacrafice of something elsewhere. I have my plans.
Everything that you do for a gain in one area, will be at the sacrafice of something elsewhere. I have my plans.
#14
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Originally Posted by Makenzie71
Oh....I guess I'll have to find a larger TB then. I thought the ports were only 30mm a piece...picked it from some random thread. And I'm not trying to find a larger one, really...just an adequate one that'll be easy to work with.
Everything that you do for a gain in one area, will be at the sacrafice of something elsewhere. I have my plans.
Everything that you do for a gain in one area, will be at the sacrafice of something elsewhere. I have my plans.
#16
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Personally I think your proposed manifold design is not a good one. I've been around rotaries for a long time and I've never seen anyone build anything like that for the street or track. There's probably a very good reason for that. Just because a tri-Y design works well for exhaust manifolds doesn't necessarily mean you can flip it around and use it one the intake side.
I'm no expert on intake manifold design, but I know enough to doubt it will be much (if any) better than stock. The reading (yes, actual books) I've done on this topic have shown me that it's a lot more complicated that it looks. If you read Mazda's engineering papers on the DEI and VDI manifolds you'll know what I mean.
I suggest you do a lot more research for yourself, and not just on forums. Books on modern race car design (not old school V8's) would be a good place to start.
I'm no expert on intake manifold design, but I know enough to doubt it will be much (if any) better than stock. The reading (yes, actual books) I've done on this topic have shown me that it's a lot more complicated that it looks. If you read Mazda's engineering papers on the DEI and VDI manifolds you'll know what I mean.
I suggest you do a lot more research for yourself, and not just on forums. Books on modern race car design (not old school V8's) would be a good place to start.
Last edited by NZConvertible; 10-14-04 at 02:25 AM.
#17
...94% correct.
Thread Starter
Oh trust me, I read a lot. Most of everything that supports what I want to do is theory...but on the flip side everything that negates my project is theory. I've only seena couple of manifolds like this, but their build was not documented or tested in any way. I don't even think they were dyno-tuned. I went through very annoying effort to contact 2 different people associated with cars with a mani like this and all I got were "duuuuuuu...it went faster" type responses...bunch of rednecks...
Anyways...basically my theory goes...on an N/A engine this wouldn't do crap. It would probably be more of a hinderence, not having a vacuum plenum and all. But on a turbo car, a gradual seperation for each runner would benefit flow...actually I'm tired and reading over what I'm writing it doesn't describe what's in my head adequately. I'll have to wait to the coffee kicks in...
The big thing is, though, that I like building things and I've enver seen this done on a 13T...so I thought I'd give it a shot. If it flops, it'll be fun in the mean time....
Anyways...basically my theory goes...on an N/A engine this wouldn't do crap. It would probably be more of a hinderence, not having a vacuum plenum and all. But on a turbo car, a gradual seperation for each runner would benefit flow...actually I'm tired and reading over what I'm writing it doesn't describe what's in my head adequately. I'll have to wait to the coffee kicks in...
The big thing is, though, that I like building things and I've enver seen this done on a 13T...so I thought I'd give it a shot. If it flops, it'll be fun in the mean time....
#18
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This is about as big and easy to work with as they get... http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW
#19
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Here's my redneck response. I ran a 75mm Mustang throttlebody on a very heavily modified S5 intake. You need to remember that adding the total area of 3 throttle plates and comparing it to one large one does not mean the same flow. The single plate will flow more but only because of one very important fact. The plenum (dynamic chamber) is a dual plane design. You have 1 throttle plate feeding 2 ports and the other 2 throttle plates feeding 2 (or technically 4) other ports. You will hit a restriction in the primary side before you do on the secondaries. This is really more applicable in practice on a high power forced induction car as the n/a just doesn't make enough power to justify the extra airflow.
What I found in drivability was that throttle response was very touchy. It took very liitle throttle to get moving alot faster. This isn't necessarily a good thing. The top end was better though but the low end was much worse. It was a big tradeoff. You really need a much smaller throttlebody if you plan to use a single plate. A 65 mm would be better. It will still flow enough provided that you have a single plane plenum. If you just want to adapt a single plate to the stock dynamic chamber, you are wasting your time. Although I ran it nonturbo, I had actually built it for use with a big single turbo and a huge port job. It was a play car so I didn't care a whole lot about daily drivability. Your gas mileage will go down. For street use this isn't a good idea. The only reason that a single throttle plate works on the RX-8 is because other valves close different runners off depending on rpm so velocity stays high. Their throttle body is not a 75 mm either. It is smaller. If you do this to your car, make sure you have a standalone ecu first. It does run with the stock ecu but once I got the Haltech on it, it took off.
What I found in drivability was that throttle response was very touchy. It took very liitle throttle to get moving alot faster. This isn't necessarily a good thing. The top end was better though but the low end was much worse. It was a big tradeoff. You really need a much smaller throttlebody if you plan to use a single plate. A 65 mm would be better. It will still flow enough provided that you have a single plane plenum. If you just want to adapt a single plate to the stock dynamic chamber, you are wasting your time. Although I ran it nonturbo, I had actually built it for use with a big single turbo and a huge port job. It was a play car so I didn't care a whole lot about daily drivability. Your gas mileage will go down. For street use this isn't a good idea. The only reason that a single throttle plate works on the RX-8 is because other valves close different runners off depending on rpm so velocity stays high. Their throttle body is not a 75 mm either. It is smaller. If you do this to your car, make sure you have a standalone ecu first. It does run with the stock ecu but once I got the Haltech on it, it took off.
#22
trying to build a racecar
I think one potential problem will be with TPS compatability. There is no guarantee that the output voltage will be the same between the two (new VS original) for a given degree of rotation.
I think you will unnecessarily sacrifice low end driveability with out a plenum. With out an air chamber to pull from the throttle could be very touchy.
Also, just because there is an plenum doesn't mean it will have bad flow. I think you will end up with competing pulse waves from the two rotors. A plenum will damp those out and allow for individual runner tuning.
All IMHO, of course.
I was thinking of using an LS1 throttle body on a custom manifold. After upgrading, those guys will give them away. A quick search on ebay found one for $5.
Good luck
I think you will unnecessarily sacrifice low end driveability with out a plenum. With out an air chamber to pull from the throttle could be very touchy.
Also, just because there is an plenum doesn't mean it will have bad flow. I think you will end up with competing pulse waves from the two rotors. A plenum will damp those out and allow for individual runner tuning.
All IMHO, of course.
I was thinking of using an LS1 throttle body on a custom manifold. After upgrading, those guys will give them away. A quick search on ebay found one for $5.
Good luck
#24
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Originally Posted by Makenzie71
3 X 30 mm = 2129.5 sqmm
1 X 75 mm = 4415.6 sqmm
...holy crap that math seems WAY off...
1 X 75 mm = 4415.6 sqmm
...holy crap that math seems WAY off...
It is pretty close.
Area of a Circle = PI x r^2
3 x 3.1415 x 15^2 = 2120.51 sqmm
3.1415 x 37.5^2 = 4417.73 sqmm
#25
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I think there's a lot that can be done with the original TB without sacrificing drivability/mileage. Mazda went to a fair bit of trouble for a fully divided primary/secondary intake path. Why not keep those benefits?
BTW, here are some pics of what a little time and some (fairly) simple tools can get you. Power increase was quite noticeable in my NA, and throttle response is immediate. The primary still opens first, so mileage/drivability is still good. However, since I knife-edged the butterflies there is a bit more airflow at a smaller throttle opening making the car feel like it has a bit more torque.
BTW, here are some pics of what a little time and some (fairly) simple tools can get you. Power increase was quite noticeable in my NA, and throttle response is immediate. The primary still opens first, so mileage/drivability is still good. However, since I knife-edged the butterflies there is a bit more airflow at a smaller throttle opening making the car feel like it has a bit more torque.