924Board.org

[dreamgts]

Hi Guys. Iv been going thru the posts a lot lately and noted that some guys here fit bike throttle bodies to the 924. This setup has to be EFI I pressume. I am interesting in knowing more on this subject since this could be a future project for me.

Have any of you guys fitted bike throttle bodies (ONLY) and if so , are they any good when compared to lets say Jenvey or Extrabuddy stuff. I think Martijnus has fitted some to his 924. Are there any other members who fitted bike throttles to their car, I would like to know. Does anyone know of any other cars which use throttle bodies as factory fit, I hear some Jap cars have them as factory fit, anyone know which ones, Id like to take a look at the set up.

thanks
dreamgts
_________________
2 PORSCHE 924 (CURRENT PROJECTS)
2 CLASSIC CORTINAS (FINISHED)
1 CLASSIC FIAT(FINISHED)
1 CLASSIC FIAT 132 2000CC(JUST PURCHASED)
4 SUV'S
2 SEDANS
1 OPEL PANEL VAN
WIFES SUZUKI ALTO

[fiat22turbo]

Pretty simple really. Each cylinder gets its own throttle body with a common shaft. One side usually has a throttle position sensor and the other has the throttle lever (sometimes the lever is in the middle) Some have injectors built in, others don't.

Keep in mind that many bike carbs are sized to flow enough air volume to keep a relatively small motor filled that is spinning at high rpms, so our slower spinning, larger motor can balance that equation out a bit.

To learn a bunch about sizing and the like, hit up TWM-Induction's website, then do some research on other ITB solutions. Google is thy friend in this situation. The 924 motor is just another motor when it comes to the sizing calculations, don't be afraid to do some "back of the napkin" calculations

If it were me, I'd buy a sidedraft weber intake, build a set of adapters to mount up a set of bike ITB's, since the bike ITB's usually mount using rubber tubing.

Hope this helps!
_________________
Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[dreamgts]

Thanks for this info fiat22turbo, I have seen that a member here chose to use 4 single GSXR1000 K2 throttle bodies, these seem to have fittings for injectors, although I cannot understand how he said he would use a 'rubber' type fuel rail, is this possible? I think they were 38mm which seems more than enough for a turbo 924.

Another question which comes to mind is the throttle bodie size, is 38mm more than enough? Can one use throttle bodies from smaller engined bikes?

Since this would be something in the future and at present I am decided on using the factory inlet and throttle body with a fuel rail, selected injectors and mega squirt,while also experimenting settings etc with this system layout, I was wondering if I could hold on to my fuel rail, fit the throttles in the future and just plug the throttle body injector holes, or would it be more pro and approriate to plug the existing injector holes and fit decent injectors in the selected throttle bodies. If the latter is chosen I will have to start all over again researching wht best injectors to fit to the throttle bodies.

As for a weber side draft inlet manifold, im not sure if this would take the rubber seals directly and as you said adaptors would have to be fabricated.I have an inlet manifold for the 924 which I am holding on to, but most probably I will try to fabricate an inlet manifold from scratch for the throttles. Im sure iv seen someone who supplies items for the fabrication of inlets and also fuel rails.

I wil also look into TWM-Induction since I have no knowledge of this site and see what it has to offer as info.

I would like to hear from other members though if they used such throttles and which way they went about it, certain minor details can only be obtained from persons who already have experience in such areas.

Thanks

dreamgts
_________________
2 PORSCHE 924 (CURRENT PROJECTS)
2 CLASSIC CORTINAS (FINISHED)
1 CLASSIC FIAT(FINISHED)
1 CLASSIC FIAT 132 2000CC(JUST PURCHASED)
4 SUV'S
2 SEDANS
1 OPEL PANEL VAN
WIFES SUZUKI ALTO

[Cedric]

If i remember correctly Joakim.S ITB manifold is based on bike throttle bodies, he is in the regions close to 400hp, so they should be enough for you to. Could they be gixxers? I dont remember, but i think it was from a 1000cc bike.
_________________
1980 924 Turbo
www.instagram.com/garagecedric/

[dreamgts]

[dreamgts]

If im seeing right, Joakims throttle bodie is situated on his plenum seen just above his alternator. it seems he is using a fuel rail with injectors fitted in the factory style position. correct me if im wrong.

dreamgts
_________________
2 PORSCHE 924 (CURRENT PROJECTS)
2 CLASSIC CORTINAS (FINISHED)
1 CLASSIC FIAT(FINISHED)
1 CLASSIC FIAT 132 2000CC(JUST PURCHASED)
4 SUV'S
2 SEDANS
1 OPEL PANEL VAN
WIFES SUZUKI ALTO

[fiat22turbo]

I was just thinking of using the sidedraft manifold would be easier since it could provide a nice flat surface with round holes that could be used to more easily adapt to a throttle body.

To do the adaptation, you'd need to have some adapter flanges made. Basically a flat flange with a matching diameter hose bib welded to it. Sort of like an Airhorn, only without the horn part, or the tapered piping.



DCOE mating flange CAD drawings are available online (I think TWM's site even has them)

Otherwise you'd likely have to cut the stock manifold off at the runners and deal with the relatively oblong runners, etc. Or build a custom manifold from scratch to mate to the throttle bodies.

Placement of the injectors doesn't matter too much for your situation. If the throttle bodies have the injectors built into them, then I'd use that location.

Rubber fuel rail basically means that each injector gets a fuel hose run to it from a distribution block, just like the original CIS system. This is instead of being fed via fuel rail. Slightly different way to do the same things.
_________________
Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[dreamgts]

Yes that would be a good set up using a weber inlet im sure. These guys www.rossmachineracing.com seem to have various bits and pieces to build throttle bodie plenum etc, just have a look at their home page for stuff. Iv been doing a lot of searching for info and its adding up. They also have an adaptor for throttle bodies which take a Mustang 75mm throttle bodie to it, I wonder if that would be ok, since one could purchase a diy kit for it, does anyone know anything about this Mustang throttle bodie, adaptors exist for 75mm and 90 mm. What do you think. Im willing to sacrifice some cash to experiment on this system on the(experimental) MG and see how it goes, Im not sure I understand you when you say using a CIS type distribution boxm are these dizzys available or does one have to fabricate it too. Thanks

dreamgts
_________________
2 PORSCHE 924 (CURRENT PROJECTS)
2 CLASSIC CORTINAS (FINISHED)
1 CLASSIC FIAT(FINISHED)
1 CLASSIC FIAT 132 2000CC(JUST PURCHASED)
4 SUV'S
2 SEDANS
1 OPEL PANEL VAN
WIFES SUZUKI ALTO

[fiat22turbo]

Yeah Ross' is pretty cool. Thinking about using their fuel rail stock and plenums on a few of my own projects.

The 75mm throttle body is huge for a SOHC 2.0L motor. The guys using those have motors that can flow that much air (dual camshafts, multiple valves, large lift camshafts or large cylinders to fill). Ours doesn't, sorry but it is sad but true. That large a throttle body could make the engine a little touchy on throttle inputs depending on the size of the plenum used, the work done to the head, the camshaft used, etc.

I would stick to throttle bodies around the 60-62mm size for a single throttle body solution with a plenum behind it if you're driving on the street or road racing/slalom racing. You might give up a little power on the top end to gain some drivability at the bottom end of the power curve.

Sort of like using an aluminum flywheel or a steel one that has been lightened over a stock flywheel. The aluminum would be faster once at speed, but can be a pain to get going at a stop light. The lightened steel would be somewhere in the middle and the stock is easiest to get away from the line but the engine won't change speed as quickly.

For an ITB solution you'd probably need a diameter only maybe half that size and a plenum would have to be designed to match the outlet of the turbo (or intercooler) so the inlet of the plenum would be as large as the diameter of the outlet of the intercooler/turbo, any larger wouldn't gain you anything since the piping diameter and the inlet of the turbo scroll limits the amount of air getting to the plenum and throttle bodies.

Keep in mind that the size or the volume of the plenum is just as important as the size of the throttle body feeding it, you really have to consider what your end goal is and how the entire system will work together. The bigger is better method doesn't always work in this situation and be prepared to do some experimentation after looking up some of the calculations used to determine components used in an engine project such as this.
_________________
Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[dreamgts]

I got the message regarding tube sizing, plenum sizing etc. I was thinking of a throttle bodie size of 60mm for single throttle yet if i use individual throttles I might be thinking of 36mm/38mm, I just have to research more about this.

I am aware that a larger capacity in plenum wont do any good, in fact I was thinking of moderate sized plenum, but this still has to be research. I might even use the factory inlet/plenum for research on capacity, I might get a good idea here I think.

So as you are saying does the tubing from the intercooler have to be the exact size diameter of the throttle bodie used if 1 throttle is used or can it differ by a little.

The best solution therefore would be to use 4 single throttles and fabricating the inlet size of the plenum the exact size of the intercooler piping or as near as possible.

My experimental plenum/throttle bodies are to be fitted to an NA engine of 2 lit which is fitted on a fibreglass bodied mg midget, in this case I cannot experiment fully (no turbo) yet I still can get the satisfaction of fabricating it and having the knowledge of what would be needed etc.

My goal since Iv decided to go for it is to prepare the engine for as much BHP as I can get using euro spec pistons, balanced lower end, lightened flywheel(but not too much) EFI, ECU, turbo. keeping boost etc under control and slowly upgrading to throttles, clutch, gear box etc. since I know the clutch and gearbox wont handle more than 215BHP, as i say to myself I think I would be happy with 215BHP on a road car but on a race car, it just wont do. I have made some changes in my engine plans since Iv joined the forum and at a time I was even going for NA/weber install again but tthat I think would have left me unsatisfied in my goals. Although the D prod look is to stay. I guess Ill just have to call the car the 933 DP-T

I have never tried to tune up a 924 before and this is new territory for me, I do have experience tuning 2 lit pinto engines but thats another story.

I would like to know if anyone has the info of what type dizzy is used to feed the injectors thru rubber piping instead of a fuel rail, so if anyone knows please post your knowledge. I tried search but nothing came up . checked up to page 19 in performance upgrades and still searching.

thanks

dreamgts


_________________
2 PORSCHE 924 (CURRENT PROJECTS)
2 CLASSIC CORTINAS (FINISHED)
1 CLASSIC FIAT(FINISHED)
1 CLASSIC FIAT 132 2000CC(JUST PURCHASED)
4 SUV'S
2 SEDANS
1 OPEL PANEL VAN
WIFES SUZUKI ALTO

[Martijnus]

[dreamgts]

Yes martijnus it was you I was refering to, pretty good job too. So you plugged the throttle bodie injector seating and used the 924 factory injector seating. I was actually thinking of doing that since to my calculations using whatever as throttles, injectors wont have to be replaced by new specs, therefore also saving a few euros on that. Only thing needed here might be some fiddling with the ECU.

Did you use a dizzy to send fuel to your fuel pipe or did you just connect the fuel feed to the filter/ pump?

When saying that you wont be using spacing, do you mean that you will be directly attaching the throttles to shorter inlet manifold?

Is it possible to post or send me a pic of the fuel pipe. Im very interested in seeing how you made this work.

Thanks

dreamgts
_________________
2 PORSCHE 924 (CURRENT PROJECTS)
2 CLASSIC CORTINAS (FINISHED)
1 CLASSIC FIAT(FINISHED)
1 CLASSIC FIAT 132 2000CC(JUST PURCHASED)
4 SUV'S
2 SEDANS
1 OPEL PANEL VAN
WIFES SUZUKI ALTO