I'm turbocharging a 455 CID/7.4 liter Buick! There is no replacement for displacement! Here's the link to my old ProStreet car, http://www.thedinosaurgang.com My lawyer said I had to sell it and give my Ex-wife 1/2 the money about 15 years ago, I sold it to the guy that helped me build all the cars we raced and got out of cars all togather until now. I was driving it on the street with a stock engine and sold him the car and all the parts for $1000USD. I paid over $1200USD for just the two tires and rims on the back. he still has it, it was in primer when he got it. It has a tube frame from the firewall back and a roll cage complete with 5 point harnesses for seat belts. I had Power steering,A/C, tilt whell and was adding cruise control when we split up. I also was starting on a twin turbo 455/7.4L engine for it then. I'm presently working on doing the same to a 1970 Buick Electra 225, basicaly what I call a land barge. I plan to install 21.5 x 33 tires on the rear like my old car and drive it for an everyday street car.

 

Does Suzuki still make a tiny car with a 3 cylinder turbo'd engine?
Does the SMART "car" (I call it a toy car) have a turbo on its tiny diesel engine?

__________________
Uncle $crooge

 

I'm not sure they are supposed to start selling the Smart Car in The US later this year I think.

 

We have the tiny SMART car in Canada now. It sells for the same price as a "normal small (much bigger) car". I laugh when I see one.

__________________
Uncle $crooge

 

Yes, all the Smart Fortwo cars are 3-cylinder turbos (petrol and diesel variants).

 

Err... Two questions:

1. Are you controlling supplementary fuel injectors or are these solenoids going to bleed boost? Just want to be certain, for issue 2:

2. O2 sensors on startup will read 0V as if it's running really lean. O2 sensors in closed loop/idle can possibly hit fairly low voltage when operating normally. Are you going to inject more fuel or bleed boost in these situations?

Optoisolators are really weak. You may have to use another external transistor (or darlingtons as posted earlier, which is the same thing) to amplify the signal a bit so that enough base current is drawn from the TIP42 to fully turn on the solenoids. But I'm thinking there's another, better way to hook up these power transistors for solenoids without the (expensive, and probably completely unnecessary) optoisolators here. However with the first two questions I don't know yet...

Oh, I guess since people are going off topic here, I'm a DSM'er and a WRX'er... though my faith in 4G63T has diminished due to my DSM's state...

 

Ans for 1 &2
Supplemental fuel added under Full throttle w/boost w/engine O2 sensors heated at operating temp.
Someone metioned using MOSFETs, how can I wired these instead of the
TIP42s? I'm looking at the data sheets for a FDS6685 Made by Fairchild, would something like this work better? They said they work off voltage unlike transistors that work off current. How might I connect one of these for switching the load? I'll check back later today, I've got to read a chapter on PLCs and get to school. catch you guys later, Floyd.

 

Confidence is something you get before you fully understand the situation... I see your issue now. The biggest problem is that your LEDs are adjustable brightness, and that complicates things. The Optoisolators is probably the easiest solution after all, since now you're decoupled from current and voltage (not saying there aren't other solutions.)

You will need to have multiple stages of amplification, it looks like the 4N25 can't really sink enough current to fight the pulldown. I'd probably use a secondary transistor - so 3 transistors total. Optoisolator, a GP transistor, say 2N3904, and the (crappy hFE=40) TIP42 all in common-emitter configuration (tip42 being PNP, E=VCC). The Optoisolator has a pullup of about 10K, Collector connects to base of the 2N3904. The 2N3904's collector will pull the TIP42's base down through a 390 ohm resistor, providing the current needed to saturate that transistor.

Sorry for a text description of how to connect but I think this should turn on a typical solenoid at saturation whenever the opto is "dark".

 

The LEDs are not adjustable brightness per say, the adjustment on the PCB is to get the 0-1V signal dialed in so the .5V signal is at the middle of the LEDs #1-#10 on the outputs going to the Optos and to compensate for the O2 sensor input. I do see what you mean abot the OPTOs though. I'm going to do a liitle more research into the Mosfets and maybe FETs and see if they might work better. I'll look around here and see if I have some 2N3904 laying around or can take some out of something. I've become a bit of a pack rat scavanger for electonic parts. I had a school mate over and he said I had more than Radio Shack. (US hobby electronics vendor)
Basicaly it sounds like what I need to do from what you are saying is use the 2N3904 sort of like what I'm trying to do with the TIP42 for the injector, but apply the load to the base of the added transistors because the OPTO cannot carry enough load to the base of the TIP42 I have now?

 

Transistors have current gain. A small base current makes a high collector current.
Your injectors are 14 ohms so they need 12V/14 ohms= 857mA of current.
The 1.6k resistor causes a base current of 11.3V/1.6k= 7mA.
But the minimum gain of a TIP42 is only about 20.
The TIP42 amplifies it at least 20 times to only 140ma.

As i said before, use TIP125 PNP darlington transistors that have a minimum current gain of 1000. Then the circuit will be exactly the same as you have now but the injectors will operate at full current. A darlington transistor has two transistors inside connected to boost the current.

__________________
Uncle $crooge

 

All the ones I've seen are petrol.

They are supposed have good fuel economy I've heard aroung 60MPG but they're slow and have a top speed of only 85MPH. I'd rather stick with my bike which will do 120MPH and is just as good on fuel.

__________________
I also post at the following sites:
http://www.stop-microsoft.org http://www.heated-debates.com
Screen name: Aloone_Jonez
And http://www.silicontronics.com, same screen name as here.

 

Well the maximum speed in the UK is 70mph!

But they are basically a car for around town, easy to drive and cheap to run, pretty nippy but no high top speed. I've never driven one, but they are semi-automatic I think?.

As suggested they are a bit pricey though, but aren't they something to do with Mercedes?.

Obviously a four stroke!.

I've had a couple of Suzuki's in the past, a 350cc (twin) and a 380cc (triple), both two strokes, and both seriously fast acceleration - top speeds about 110mph. Fuel consumption though! - you might make 30mph on a good day!

An old friend of mine used to have a BMW, 900cc horizontally opposed twin, before that he bought a Yamaha 750cc four cylinder. We were talking one day and he said the Yamaha was absolutely rubbish - it didn't perform very well for a 750, and it had poor fuel economy. As a result he changed it for the BMW - this would cruise all day at 120mph, and no matter what you did still returned 75-80mph - pretty impressive machine!.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

The max allowed speed in Canada is 100km/h but I had my turbo car doing over double that and it was still accellerating. I didn't get caught speeding.
My new cars have a darn governor set to the tire spec's. It is dangerous to pass on a two-lane road when a big truck is coming at you and the governor cuts off the engine.

__________________
Uncle $crooge

 

Thanks, that's put pretty simple that I can understand, I'll see if I have some around here if not I'll get some and try it. When looking at specs on a data sheet for something like this what do I need to compare? Just get a TIP125 and a TIP42 sheet and see what the differance is?

 

It is obvious that the TIP125 darlington transistor has a current gain that is at least 50 times more than the TIP42 transistor.

Attached Images

TIP comparison.PNG (5.2 KB, 7 views)

__________________
Uncle $crooge