They come in a DCNF configuration: http://www.redlineweber.com/SEMA2002/flyers/Throttle_body.htm Image Unavailable, Please Login
Hey Paul and good question. I know you know this stuff but there is no venturi in a throttle bodie it just is not needed because the fuel is being injected. I believe this allows you to use a bigger TB to a comparable carb. I think the big problem for you carb guys is that you have to compromise some what so you can get a good idle and then top end performance due to the venturi effect. I have no idea how you size a TB but Mark E seems to believe some where between 44 to 40mm would work for a 308. My TB are about 38mm and they should work great also. I looked at the throttle bodies you posted pics of and I would go that route but you will easily add 3000 bucks to the bottom line when all is said and done. I paid 275 for my 8 TB with injectors. I believe one IDF or DCNF runs about 350 just for the casting? Then the manifold that will need to be made is certainly more complex than the manifold that will be used for the motorcycle TB(pics above). I know you know all about manifold fabrication. LOL By the way Merry X-mas!! Bill
I really don't know to much about this stuff but am now learning quickly (thanks to Russ and Mike at Pierce). What if your throttle body is too large or too small how do you regulate air flow? As I learned 36mm would be a perfect size for a 308 if it were a perfect 100% Efficient engine but now I am moving to a 34mm. Paul And a Merry Christmas to you as well.
Well I have no idea what would be the perfect size. Bigger is better yea?LOL I do know that a Honda 1000 CBR uses 44 mm TB and makes about 150 to 175hp. I know Mark is the guy who has played around with both systems alot. I am sure he will chime in. You should switch to the dark side of EFI Paul and inject that Bad boy you have. I know you would find more usable hp. Like you will need it. Since you are just about done with your ride you will have plenty of time work on it again. LOL
Most of the faster motorcycle race motors are using shower injectors, where the injectors are placed above the inlet venturi. Would this be an advantage on the F motor? Is there an intrinsic advantage to 8 individual throttle butterflies as opposed to one giant throttle leading into a manifold? I would think the the single throttle body would have less flow restriction.
Shower injectors would be fine, the F1 V10 uses them by the looks of it in pics Ive seen with the intake tub off.
In truth, a single plenum system is probably 'better' than the 8 ITBs, especially if a boosted scenario is in the future. I'll admit that one reason I'm looking at this instead of just machining the existing intake is aesthetics. I don't really like the looks of most EFI 308/328 motors. No matter what I do, the 328 isn't going to be a Z06 killer, so I might as well get the cool velocity stacks Take a look at this set on an Alfa motor. Yummmm The other advantage seems to be price. I've been looking for a 328/QV intake runner set, and everyone's quoting in the 600 range just for the runners. For that price, I can get 2 sets of motorcycle ITBs and a couple of adapters machined. Image Unavailable, Please Login
From what others have said on tis subject I think that one large TB effects throttle response(sluggish). I got this info while discussing intake ideas with Mark E who has done dyno work on both set ups. He said in all cases ITB produced more hp. The shower injection would work great if not for the clearence between the engine and the hood. If you open up the hood like Paul sloan has done then you can do alot of things like increase the velocity stacks to almost any length you want. I am trying to keep the origanal look as best I can. Like Tillman I do not like the current manifold fabrication but it certainly would be better suited for forced induction. Bill
There's a few responses already, but I'll add my thought here too. As Bill pointer out, an EFI throttle body is actually quite different from a carb body ever though they look similar. A TB doesn't have a venturi, just a throttle plate, or the really fancy ones use a flat slide. because there is no venturi, sizing them is different than sizing a carb. With a TB on a performance engine you really can't go too big in most case from a performance stand point. Once it's big enough not to be restricting flow in any way, going bigger doesn't help, but it normally doesn't hurt either unless there is a big step or something where the huge TB sits on a smaller manifold. TBs generally make a touch more hp than carbs just because you can go up that one extra size with a TB that you can't do with a carb...it's general a relatively small gain though. The biggest gain is generally drivability since an engine with a huge TB can still idle like one with a small carb. But if the carb are well sized and set-up they work quite well too. The only problem with going big general is the way the gas pedal feels as far as engine reaction to motion...it can get sensitive. the solution is some form of progressive linkage. On my car, the lever arm (cam really) the cable operates is about 2" long near idle to make the butterfly move very little when the pedal moves because the butterfly is so big, just a small movement changes flow a lot. But near WOT the arm is about 3/4" so the buttery really moves fast though the last 1/3 of it's motion when not much is changing flow wise. It would be nearly undriveable with a standard linear throttle cam on it. On a really well designed system like the new Ferraris the manifold and TB are really just port extensions with about a 4 degree taper from the top of the stack down to the valve, the butterfly is exactly 1/2 way between the valve and top of stack and there is a helmholtz (sp?) resonator on top. A well designed ITB system will generally out perform a single TB plenum system simply because the air makes fewer turns, so the flow is better. BUT a really good manifold/plenum design can and will beat ITB (or multi-weber) set-up that doesn't include a proper resonator chamber on top....but it had to be a good manifold.
Had some toys arrive in the mail today. Pics below. These are the 36mm versions off of a GSXR 600. Perhaps not the best for top end power but I want to make sure driveability stays good. I have 2 choices, A) break apart the TBs and create custom fuel rails, linkages, etc. B) Create a manifold with curving runners to mate the TBs to the intake ports. I was going to go with A, but the 2nd pic shows that curved runners wouldn't be too different than what the factory did. If I go that way, I get to use the factory fuel rails and rail mounts, and throttle linkages. Hmmmm... Opinions? I'm sure this bunch has some No work on this until after the 15th, then we'll see. Image Unavailable, Please Login Image Unavailable, Please Login
The stock 600 injectors flow at a purported 240cc/min (22.9 lb/hr) @ 45 psi (I'm trying to verify these numbers), and according to the Megasquirt manual that's enough to fuel just over 300 HP with 8 injectors. It's a bit close though, I may go with a bit higher fuel pressure or alternatively there's a 315 cc Toyota injector that fits with minor tweaks to the fuel rail. Obviously if I go to custom spacing and fuel rails, almost anything can be made to work. The GSXR 750 and 1000 actually share the same injectors.
No permanent mod's to the manifold were required. I also got the fuel rail to fit under the throttle body. Sean. Image Unavailable, Please Login Image Unavailable, Please Login
I like tillmans set up and luckydynes, I would prefer to get outside air though rather than above the header, much better than the CIS im sure.
Cool. I've got a set of 38mm off a 750 that Bill (harta320) sent me to make a simple intake for. He's going to re-space them re-do the fuel rail so the intake is very simple and straight with room for stacks or a plenum on top. If you decide to go the curved runner root, you may have trouble with hood clearance, unless you put some real bents in them.
Runs and sounds great in the garage!!! There's a few loose ends I need to tie up before doing anything out of the local hood. I will ultimately feed fresh air . . . just couldn't wait to start and drive it with efi!!! Sean
Care to describe what you did, especially with the injector ports? How are you retaining the injectors and the fuel line? Thanks t
It looks good Sean. What did you end-up using for an ECU? Also, are the injectors retained in the manifold or just pushed in? I ask because if I recall you were considering forced induction as a next step weren't you?
The injectors are held in threaded "adapters" by a seperate retainer which locks on a "step" on the injector body . . . the lines are held on to the injector via a wire thru a groove in the injector body . . . I spent a lot of time making it all fit and will gladly make some more for fellow chatters . . . I only just fired her up so there could be gremlins lurking though. I know . . . pic's must follow. Sean
Haltech E6x ECU . . . I'm thinking nitrous next for some instant gratification (for the car that is) . . . the efi was a long time coming. Sean
Well, now that you have EFI, the possibilities are endless. How are you finding the haltech to setup and tune? Ive always though they are about the easiest, but I know other find them confusing .maybe just a question of what you learn on.
I found it pretty easy to set up, but I do have quite a bit of control system exprience. I have a wideband O2 system which has also been a big help. Thanks again to everyone (especially you Mark) for sharing info and expriences on the forum . . . Sean
For the record, the original converter bungs shown in the first post do not work with the 3.2 intake. When things get settled around here I'm going to take some measurements and send them to the designer. He seemed interested in creating something plug-n-play for the 328
