Individual Throttle Bodies

[miragesmack]

Myabe you can put together a kit with instructions. You might have a few buyers here.

[Hjulenx]

That is certainly a possibility. The guys at extrudabody have been hinting for me to do just that. It may be easier though for me to post a parts list with part numbers and just let the Fiat community have at it. There are a couple of different ways you can go about it, and if anyone wanted me to put something together for them I certainly would. I would wait to do that though until I get a nice solid tune on my own vehicle and find out all the bugs. I don't want anyone else to be the ginnie pig for expensive and potentially hazards projects, particularly if my name was to be attached to it.

Though just as a warning to anyone who wants to attempt the same thing. You really have to do your homework otherwise you will get frustrated. Patience is the number 1 virtue in a project like this...

[spiderrey]

once you get this thing done, and the bugs all worked out, im all over it. its the last thing my car needs before i start addressing all the cosmetics.if you could post as much details about the process as possible, it would be appreciated. the only thing i would think about possibly doing differently might be using a side draft set up if the throttle bodies would clear the brake m c.and i would have to find out if they made throttle bodies to fit a dcoe manifold. thanx reyy

[Hjulenx]

Took it on the road last week, pretty sweet. After some initial tuning I got it running well enough to run on the main streets. I am still having some problems with the manifold pressure signal gooning up my tuning resolution, but the car doesn't seem to mind.

The car growls. My initial impressions are that it has slightly less low end torque then the previous setup (however, that will be solved with tuning). Even in the loose tune I have it in now it screams to redline, which definitely was not the case before. I am going to try and track down the MAP issues before I move to the next step, which is acceleration enrichment tuning.

That is the most interesting part of the project in my opinion; there are some pretty cool algorithms that the ECU uses to help out with those. The Tau-X algorithms are the neatest I think because the help calculate fueling in transient engine conditions such as during warmup and accel/deceleration. They do this by estimating the effects of the 'wall wetting phenomenon.' Breaking through the countless SAE papers on the subject, the jist is that not all the fuel injected by the fuel injectors makes it into the cylinders. Some of it pools on the intake manifold walls...the amount that is one the walls is dependent on a few factors....temperature, manifold pressure, and all kinds of other engine specific factors. (The is why you carb guys have accel jets.)

The computer algorithm instead of trial and error breaks down the amount of fuel on the intake wall (x) and the amount of time the fuel stays on the wall before evaporating into the cylinder (Tau). In an acceleration situation the amount of fuel on the walls goes up. Remember how water boils at different temperatures according to pressure? So does fuel. When you stomp on the gas, the pressure in the intake runners shoots up and the 'puddles' of fuel don't evaporate as readily and the mass of the fuel puddling on the walls (x) increases. More of the injected fuel then isn't getting into the cylinders because its on the manifold walls! Hence, if your acceleration enrichments aren't tuning properly you get a lean 'spike' in air to fuel ratio. The opposite is true of deceleration conditions. The pressure in the manifold drops, and the fuel evaporates more readily, the mass of the puddled fuel (x) then drops significantly. Since the newly evaporated fuel has to go somewhere, this has the effect of releasing MORE fuel into the cylinders then you think you are injecting!

Ok, more information then you were looking for, but I am an FI nerd.

[So Cal Mark]

not TMI at all, very interesting stuff. It's really cool to see some of the R&D being done with cameras in the cyls and runners

[Hjulenx]

Sweet. Today I finally got everything how I want it. Throttle linkage feels like stock with two return springs (what a PITA). I finally figured out that I had the cam timing wrong and it was causing me to get a very low vacuum signal. Redid the timing belt and walla! Car drives fantastic now, fantastic low end torque. I haven't really taken it much past 4500 rpm yet as I would like to change the oil, bleed the coolant, and tighten up a few odds and ends first. I am getting a high pitch rattle like sound which I believe to be coming from the timing belt tensioner...though it could be detonation? Doubtful, but I can always pull some timing off just to be safe.

As of right now she pulls from idle in any gear, much more available power down low than before. The cam and throttle bodies are really suppose to open up the top end, so I can't wait tell I start the tuning there! I will try and get a video of the car driving soon, I am showing it at a local cruise in show tonight, so we shall see how people like it!

[miragesmack]

Hjulenx,

So, how did the cruisers like your setup? Any more results?

[Hjulenx]

So far I have been juggling getting ready for a move and my hobbies.

On the hobby side I have been working on tightening up some fuel leaks. The hardline to AN fitting adapters are a little difficult to get right and my fuel pressure regulator was leaking a little bit. I threw a conservative amount of teflon tape on (gas resistant type and being careful to keep the tape away from the innermost threads).

I will try putting the car through its paces and so if I can't find any more leaks.

The car got a lukewarm reception at the cruise-in. Not to say that people didn't love the car, but since they are all mostly Detroit iron fanatics I don't think they really appreciated it that much. Some of the guys with European cars though really liked it.

[Mike_S]

Very impressive.

I added Megasquirt and Motorcycle ITB's to my Spider last year, although it's no where near as pretty as your setup.. I've now got 10,000 miles on the setup and love it.


GSXR Throttle bodies (38mm) mountes on a custom manufactured manifold (oh alright, so its a piece of 1/4" plate with some electrical conduit welded to it.


Edis Wheel and Coil pack, no need to change those point again


My daily driver for the last two years.

[ventura ace]

James,
Rey,
Mike,
Somehow, I've missed out on this thread until I discovered it tonight, and I'm quite impressed at what you've done / are doing. Thanks for sharing the progress. Great job!

Alvon

[Hjulenx]

Mike,

Your setup is slick. The motorcycle throttlebody route was what I was originally going to do, I had even bought some GSXR600 throttles off ebay but I decided it would have taken more fabrication then I had time for (ie I don't know how to weld, so couldn't make a custom intake manifold myself!). The ones I bought had the computer controlled secondary butterflies and would have been a PITA to plug up and such.

The flow on your setup is much more direct into the head which is nice. I also like that those throttles are a little smaller (38mm vice mine which are 40mm) which I think is more appropriately sized for our engines/power level. I kinda wish I was dealing with straight up traditional hose clamps instead of these AN/NPT fittings, but that's because I have never used them before so it takes some getting used to.

I remember seeing pictures of your setup awhile ago. Another thing I think is neat is how you mounted the coil to the dizzy location on the head.

What ECU are you using for tuning and how has that been going for ya? We should trade maps and compare notes.

[racydave]

This stuff is kickass! I did the ignition thing, and had the crank pulley and pick-up made in Texas. First after a long wait, the parts were incorrect. Wasted a whole summer waitin on correct parts... Now, the pick-up for the reluctor is on the bottom. I welded a bracket for the coil pak for the left front, and can use standard Escort plug wires. My ignition map is on the Megajolt site, but the engine is fairly stock, would like to compair the map to someone elses, but it seems pretty good! I also mounted the electronics under the dash. Ill try to post a pic, but if not they are on Flickr...http://flickr.com/photos/wwwfiatspidercom/2231809468/

[lanciahf]

James.

I want to megasquirt my stock Fiat FI maifold. Can you tell me which TPS you used and where you got the TPS tp Manifold adapter bracket.


Thanks,
Ralph