2.0 EFI turbo build

[boxdogracing]

I'am getting ready to install a turbo on my 83 spider. I think I have the ignition and fuel sorted out, but have a couple questions. First the turbo requires oil feed and drain back lines. Previous turbo builds I've done, I picked up the oil feed at the oil press sender, the Fiat has some odd (probably metric) threads at the sender I cant seem to match. Unless I find another option I plan to drill and tap the oil filter mount. Also I will be running the Bosch L-Jetronic EFI for now, and need to make sure the computer doesn't lean out under boost. I have heard to run a hobbs switch to disconnect the o2 sensor under boost. My thought is to use the hobbs switch to close the WOT contacts on the TPS, to trick the computer into thinking anything less than 1-3hg of vacuum is WOT. Any thoughts or ideas appreciated.

[pastaroni34]

I make a part to fix your oil issue. I call it a Fiat Oil Block Sandwich Plate. Check it out. Its simply a part that bolts between the oil filter block and the engine block. Other than that you just need an oil drain back into the sump.

As for fueling, I've had success using a switch to turn on an extra injector (can be your already existing cold start injector) during boost. Its pretty crude though. You could use a hobbs switch but since I was using Megajolt, I just used one of the optional outputs because it already has MAP input. Megajolt also does well with retarding the ignition timing. If you use the stock distributor you wont have much choice but to retard the overall advance curve, regardless of what your boost level is.

[Zmatt]

I know that a lot of guys who run nitrous will add another injector in the intake somewhere and will turn it on when nos is added. You could try something similar under boost. Again, it's kind of crude. L-Jetronic isn't made for turbos. You should probably go for a standalone replacement sometime down the road.

[boxdogracing]

Update build in progress. I just finished my turbo header, currently mocked up on the car with a new t3/t4 hanging off it. Above that I mounted a 40mm external wast gate. I will be running a liquid to air intercooler, with a front mounted heat exchanger. As of right now I have a exponential rising rate fuel pressure regulator, and an adjustable primary regulator along with the hobbs switch connected to the TS. I have a set of 420cc injectors, and Megasquirt in the works.


some pics of progress
http://s1124.photobucket.com/home/rustf ... ng77/index

[htchevyii]

Here's a link to a low budget turbo build:


http://users.chartertn.net/jseabolt/80spider.htm

[Zmatt]

Update build in progress. I just finished my turbo header, currently mocked up on the car with a new t3/t4 hanging off it. Above that I mounted a 40mm external wast gate. I will be running a liquid to air intercooler, with a front mounted heat exchanger. As of right now I have a exponential rising rate fuel pressure regulator, and an adjustable primary regulator along with the hobbs switch connected to the TS. I have a set of 420cc injectors, and Megasquirt in the works.


some pics of progress
http://s1124.photobucket.com/home/rustf ... ng77/index

regarding your setup, I noticed you have what appears to be a custom intake manifold as well. Is that an all new unit or a modified FI spider one? Also, what sensors are you running to megasquirt? Are you going to monitor everything or just the bare essentials?

[boxdogracing]

Zmatt I'am guessing you where looking at the liquid to air intercooler, The intake in the pictures is completely stock. My original plan was to run the L-jet EFI, as shown in the pictures the only mod needed to the intake is to remove/relocate the crankcase breather tube just ahead of the throttle body. I may still run the L-jet for a short time while I sort out the rest of the mechanical install. However boost will have to be very limited 6-8psi, I'am guessing, maybe less.

As for the megasquirt install I have a different intake manifold that has an intake air temp sensor where the crankcase vent used to be, I also cut the throttle plate shaft on the TPS side and added a plate to fit a throttle position sensor from a Cadillac catera (Fiat only used a switch). The cold start injector has been removed. I have also fitted this manifold with 40lb injectors, and a knock sensor. For the sensors ect. I'am using GM parts just for ease of availability, and I'am most familiar with them. Megasquirt is nice that you can use any sensors you want, but each one requires research and programing specific to that component. Components for my build include: TPS (sensor), intake air and coolant temp sensors, an Innovate wide band O2, a modified Jeep 4.0 IAC, a GM LT1 knock sensor, and a GM 7-pin HEI module. The addition of these parts should eliminate the need to limit boost due to a weak fuel system, and see how far you can take a fiat on boost. BTW any one got a short block near Wash. DC for when I find I've gone to far?

[Zmatt]

Thanks for the reply, are you using a modified fiat intake or is this a custom job? Any indepth writeup would be very useful. i'm currently researching the cost/feasibility/possibility of doing this as well so any information is helpful.

[fiatfactory]

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[boxdogracing]

Thanks for the advice I definitely will look into bigger less restrictive oil drain. I had not thought of the issues you mentioned on that one. The exhaust in the pic is 2.5", and the little pipe is my temp solution for PVC. The wast gate has a 2" dump pipe not shown in pics. Everything is subject to change as solutions are required, and I will add pics of problems and solutions as they come. I also noticed the clearance to the engine mount, heat shields will come at some point, hell right now the intercooler is mounted right over the header with nothing between them.

I did fire it up yesterday did not move yet, I found and fixed a oil leak, and was able to heat cycle the header and turbo ect. Right now the exhaust is just dumping behind the front wheel, man it sounds cool (neighbors called it loud). I have a few little things left, maybe drive a little tomorrow.

[boxdogracing]

Up and running! Still using the L-jet for now basically just to see if I can make it work. so far I have been able to maintain 7-8psi boost, WOW it's like a different car. At these boost levels I'am over 80psi on the fuel injectors, they seem to be holding up fine so far. I still have bugs to work out, and I can't justify much more time or money in tuning with the L-jet when I have Megasquirt waiting.

Driving impressions now are completely different than before the turbo. Most obvious is that the turbo will push air past the throttle butterfly, so very little peddle and vacuum drops and boost builds. I'am happily surprised that boost comes on very fast, just 2K rpm and 1/2 throttle results in boost almost instantly. I'am still babying it so far. I haven't tried to run boost anywhere near red line, but 2-3k it pulls like a much larger motor, and over 3k it really starts to come alive. I tend to chicken out soon after 4K. I have come to far to grenade it now. Man this is fun.

[Raze]

When you go MS, one of the nice things you can do is run much larger injectors w/o having to run higher fuel pressure as long as you dial in your PW and allow duty cycle overhead. Depending on which MS versions you get MS-I/II/III proc you'll have different VE table size (later processors have larger tables) which will help you adjust drive-ability, especially off-idle and part-power with much larger injectors. My buddies and I setup a MS-I on a v3.0 board w/MSnS extra code on our XR4Ti which only has 10x10 table size or something like that and went from 35#/hr injectors to 75#/hr injectors as we went from running 15psi through the stock T3 to 30psi through a Holset HY35 (i.e. we didn't just turn up the boost, we turned up the flow rate too!). Needless to say we were concerned about drive-ability as we do drive it to the track and back. Even with a smaller table we were able to dial it in nicely. There are table calculators online to determine how much duty cycle you will be running at a given flow rate for a given injector. We went conservative knowing we'd turn up the boost to the limits of the turbo/motor combo so we sized it so we would never go beyond 75% duty cycle. Older injectors (or cheaper ones) tend to lock at high fuel pressures and duty cycles which = kaboom.